Release v0.28.0

Fixes bug where certain input values for top/left parameters
in composite can conflict with clipping logic, resulting in
inaccurate alignment in output.

.cirrus.yml

@@ -0,0 +1,15 @@
+freebsd_instance:
+  image_family: freebsd-13-0-snap
+
+task:
+  name: FreeBSD 13.0
+  env:
+    IGNORE_OSVERSION: yes
+  prerequisites_script:
+    - pkg update -f
+    - pkg upgrade -y
+    - pkg install -y pkgconf vips node npm
+  install_script:
+    - npm install --build-from-source --unsafe-perm
+  test_script:
+    - npm test

.editorconfig

@@ -0,0 +1,12 @@
+# http://editorconfig.org
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false

.gitattributes

@@ -0,0 +1 @@
+src/libvips/* linguist-vendored

.github/CONTRIBUTING.md

@@ -0,0 +1,97 @@
+# Contributing to sharp
+
+Hello, thank you for your interest in helping!
+
+## Submit a new bug report
+
+Please create a [new issue](https://github.com/lovell/sharp/issues/new) containing the steps to reproduce the problem.
+
+If you're having installation problems, please include the output of running `npm install --verbose sharp`.
+
+New bugs are assigned a `triage` label whilst under investigation.
+
+## Submit a new feature request
+
+If a [similar request](https://github.com/lovell/sharp/labels/enhancement) exists,
+it's probably fastest to add a comment to it about your requirement.
+
+Implementation is usually straightforward if libvips
+[already supports](https://libvips.github.io/libvips/API/current/func-list.html)
+the feature you need.
+
+## Submit a Pull Request to fix a bug
+
+Thank you! To prevent the problem occurring again, please add unit tests that would have failed.
+
+Please select the `master` branch as the destination for your Pull Request so your fix can be included in the next minor release.
+
+Please squash your changes into a single commit using a command like `git rebase -i upstream/master`.
+
+To test C++ changes, you can compile the module using `npm install --build-from-source` and then run the tests using `npm test`.
+
+## Submit a Pull Request with a new feature
+
+Please add JavaScript [unit tests](https://github.com/lovell/sharp/tree/master/test/unit) to cover your new feature.
+A test coverage report for the JavaScript code is generated in the `coverage/lcov-report` directory.
+
+Where possible, the functional tests use gradient-based perceptual hashes
+based on [dHash](http://www.hackerfactor.com/blog/index.php?/archives/529-Kind-of-Like-That.html)
+to compare expected vs actual images.
+
+You deserve to add your details to the [list of contributors](https://github.com/lovell/sharp/blob/master/package.json#L5).
+
+Any change that modifies the existing public API should be added to the relevant work-in-progress branch for inclusion in the next major release.
+
+Please squash your changes into a single commit using a command like `git rebase -i upstream/<wip-branch>`.
+
+### Add a new public method
+
+The API tries to be as fluent as possible.
+Image processing concepts follow the naming conventions from libvips and, to a lesser extent, ImageMagick.
+
+Most methods have optional parameters and assume sensible defaults.
+Please ensure backwards compatibility where possible.
+
+Feel free to create a [new issue](https://github.com/lovell/sharp/issues/new) to gather feedback on a potential API change.
+
+### Remove an existing public method
+
+A method to be removed should be deprecated in the next major version then removed in the following major version.
+
+By way of example, the `background()` method present in v0.20.0 was deprecated in v0.21.0 and removed in v0.22.0.
+
+## Documentation
+
+The public API is documented with [JSDoc](http://usejsdoc.org/) annotated comments.
+
+These can be converted to Markdown by running:
+```sh
+npm run docs-build
+```
+
+Please include documentation updates in any Pull Request that modifies the public API.
+
+## Run the tests
+
+### Functional tests and static code analysis
+
+```sh
+npm test
+```
+
+### Memory leak tests
+
+Requires [Valgrind](http://valgrind.org/).
+
+```sh
+npm run test-leak
+```
+
+## Finally
+
+Please feel free to ask any questions via a
+[new issue](https://github.com/lovell/sharp/issues/new).
+
+If you're unable to post details publicly, please
+[e-mail](https://github.com/lovell/sharp/blob/master/package.json#L5)
+for private, paid consulting.

.github/FUNDING.yml

@@ -0,0 +1 @@
+open_collective: libvips

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,5 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Documentation
+    url: https://sharp.pixelplumbing.com/
+    about: Installation instructions, complete API documentation with examples, changelog

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,16 @@
+---
+name: Feature request
+about: Suggest an idea
+labels: enhancement
+
+---
+
+What are you trying to achieve?
+
+Have you searched for similar feature requests?
+
+What would you expect the API to look like?
+
+What alternatives have you considered?
+
+Is there a sample image that helps explain?

.github/ISSUE_TEMPLATE/installation.md

@@ -0,0 +1,22 @@
+---
+name: Installation
+about: Something went wrong during either 'npm install sharp' or 'require("sharp")'
+labels: installation
+
+---
+
+Did you see the [documentation relating to installation](https://sharp.pixelplumbing.com/install)?
+
+Have you ensured the architecture and platform of Node.js used for `npm install` is the same as the architecture and platform of Node.js used at runtime?
+
+Are you using the latest version? Is the version currently in use as reported by `npm ls sharp` the same as the latest version as reported by `npm view sharp dist-tags.latest`?
+
+If you are using npm v6 or earlier and installing as a `root` or `sudo` user, have you tried with the `npm install --unsafe-perm` flag?
+
+If you are using npm v7, does the user running `npm install` own the directory it is run in?
+
+If you are using the `ignore-scripts` feature of `npm`, have you tried with the `npm install --ignore-scripts=false` flag?
+
+What is the complete output of running `npm install --verbose sharp`? Have you checked this output for useful error messages?
+
+What is the output of running `npx envinfo --binaries --system`?

.github/ISSUE_TEMPLATE/possible-bug.md

@@ -0,0 +1,20 @@
+---
+name: Possible bug
+about: Installation of sharp was successful but then something unexpected occurred using one of its features
+labels: triage
+
+---
+
+<!-- If this issue relates to installation, please use https://github.com/lovell/sharp/issues/new?labels=installation&template=installation.md instead. -->
+
+Are you using the latest version? Is the version currently in use as reported by `npm ls sharp` the same as the latest version as reported by `npm view sharp dist-tags.latest`?
+
+What are the steps to reproduce?
+
+What is the expected behaviour?
+
+Are you able to provide a minimal, standalone code sample, without other dependencies, that demonstrates this problem?
+
+Are you able to provide a sample image that helps explain the problem?
+
+What is the output of running `npx envinfo --binaries --system`?

.github/ISSUE_TEMPLATE/question.md

@@ -0,0 +1,16 @@
+---
+name: Question
+about: For help understanding an existing feature
+labels: question
+
+---
+
+<!-- If this issue relates to installation, please use https://github.com/lovell/sharp/issues/new?labels=installation&template=installation.md instead. -->
+
+What are you trying to achieve?
+
+Have you searched for similar questions?
+
+Are you able to provide a minimal, standalone code sample that demonstrates this question?
+
+Are you able to provide a sample image that helps explain the question?

.github/workflows/ci.yml

@@ -0,0 +1,87 @@
+on:
+  - push
+  - pull_request
+jobs:
+  CI:
+    runs-on: ${{ matrix.os }}
+    container: ${{ matrix.container }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: ubuntu-20.04
+            container: centos:7
+            nodejs_version: 10
+            coverage: true
+            prebuild: true
+          - os: ubuntu-20.04
+            container: centos:7
+            nodejs_version: 12
+          - os: ubuntu-20.04
+            container: centos:7
+            nodejs_version: 14
+          - os: ubuntu-20.04
+            container: centos:7
+            nodejs_version: 15
+          - os: ubuntu-20.04
+            container: node:10-alpine3.11
+            prebuild: true
+          - os: ubuntu-20.04
+            container: node:12-alpine3.11
+          - os: ubuntu-20.04
+            container: node:14-alpine3.11
+          - os: ubuntu-20.04
+            container: node:14-alpine3.13
+          - os: ubuntu-20.04
+            container: node:15-alpine3.11
+          - os: macos-10.15
+            nodejs_version: 10
+            prebuild: true
+          - os: macos-10.15
+            nodejs_version: 12
+          - os: macos-10.15
+            nodejs_version: 14
+          - os: macos-10.15
+            nodejs_version: 15
+          - os: windows-2019
+            nodejs_version: 10
+            prebuild: true
+          - os: windows-2019
+            nodejs_version: 12
+          - os: windows-2019
+            nodejs_version: 14
+          - os: windows-2019
+            nodejs_version: 15
+    steps:
+      - name: Dependencies (Linux glibc)
+        if: contains(matrix.container, 'centos')
+        run: |
+          curl -sL https://rpm.nodesource.com/setup_${{ matrix.nodejs_version }}.x | bash -
+          yum install -y gcc-c++ make git python3 nodejs
+      - name: Dependencies (Linux musl)
+        if: contains(matrix.container, 'alpine')
+        run: apk add build-base git python3 --update-cache
+      - name: Dependencies (macOS, Windows)
+        if: contains(matrix.os, 'macos') || contains(matrix.os, 'windows')
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.nodejs_version }}
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Fix working directory ownership
+        if: matrix.container
+        run: chown root.root .
+      - name: Install
+        run: npm install --build-from-source --unsafe-perm
+      - name: Test
+        run: npm test
+      - name: Coverage
+        if: matrix.coverage
+        uses: coverallsapp/github-action@v1.1.2
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+      - name: Prebuild
+        if: matrix.prebuild && startsWith(github.ref, 'refs/tags/')
+        env:
+          prebuild_upload: ${{ secrets.GITHUB_TOKEN }}
+        run: npx prebuild --runtime napi --target 3

.gitignore

@@ -1,15 +1,18 @@
-lib-cov
-*.seed
-*.log
-*.csv
-*.dat
-*.out
-*.pid
-*.gz
-
-pids
-logs
-results
 build
 node_modules
-tests/fixtures/output.*
+/coverage
+test/bench/node_modules
+test/fixtures/output*
+test/leak/libvips.supp
+test/saliency/report.json
+test/saliency/Image*
+test/saliency/[Uu]serData*
+!test/saliency/userData.js
+vendor
+.gitattributes
+.DS_Store
+.nyc_output
+.vscode/
+package-lock.json
+.idea
+.firebase

.npmignore

@@ -1,18 +0,0 @@
-lib-cov
-*.seed
-*.log
-*.csv
-*.dat
-*.out
-*.pid
-*.gz
-
-pids
-logs
-results
-build
-node_modules
-
-.gitignore
-tests
-.travis.yml

.prebuildrc

@@ -0,0 +1,4 @@
+{
+  "include-regex": "(sharp\\.node|libvips-cpp\\.dll)",
+  "strip": true
+}

.travis.yml

@@ -1,17 +1,108 @@
-language: node_js
-node_js:
-  - "0.10"
-  - "0.11"
-before_install:
-  - sudo add-apt-repository ppa:lyrasis/precise-backports -y
-  - sudo apt-get update -qq
-  - sudo apt-get install -qq automake gobject-introspection gtk-doc-tools libfftw3-dev libglib2.0-dev libjpeg-turbo8-dev libpng12-dev libwebp-dev libtiff4-dev libexif-dev libxml2-dev swig graphicsmagick libmagick++-dev
-  - git clone https://github.com/jcupitt/libvips.git
-  - cd libvips
-  - git checkout 7.38
-  - ./bootstrap.sh
-  - ./configure --enable-debug=no --enable-cxx=yes --without-orc --without-python
-  - make
-  - sudo make install
-  - sudo ldconfig
-  - cd $TRAVIS_BUILD_DIR
+jobs:
+  include:
+    - name: "Linux ARM64v8 (Debian 11, glibc 2.29) - Node.js 10"
+      arch: arm64
+      os: linux
+      dist: bionic
+      language: shell
+      before_install:
+        - sudo docker run -dit --name sharp --volume "${PWD}:/mnt/sharp" --workdir /mnt/sharp arm64v8/debian:bullseye
+        - sudo docker exec sharp sh -c "apt-get update && apt-get install -y build-essential git python3 curl"
+        - sudo docker exec sharp sh -c "curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add -"
+        - sudo docker exec sharp sh -c "echo 'deb https://deb.nodesource.com/node_10.x sid main' >/etc/apt/sources.list.d/nodesource.list"
+        - sudo docker exec sharp sh -c "apt-get update && apt-get install -y nodejs=10.*"
+      install: sudo docker exec sharp sh -c "npm install --build-from-source --unsafe-perm"
+      script: sudo docker exec sharp sh -c "npm test"
+      after_success: "[[ -n $TRAVIS_TAG ]] && sudo docker exec --env prebuild_upload sharp sh -c \"npx prebuild --runtime napi --target 3\""
+
+    - name: "Linux ARM64v8 (Debian 11, glibc 2.29) - Node.js 12"
+      arch: arm64
+      os: linux
+      dist: bionic
+      language: shell
+      before_install:
+        - sudo docker run -dit --name sharp --volume "${PWD}:/mnt/sharp" --workdir /mnt/sharp arm64v8/debian:bullseye
+        - sudo docker exec sharp sh -c "apt-get update && apt-get install -y build-essential git python3 curl"
+        - sudo docker exec sharp sh -c "curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add -"
+        - sudo docker exec sharp sh -c "echo 'deb https://deb.nodesource.com/node_12.x sid main' >/etc/apt/sources.list.d/nodesource.list"
+        - sudo docker exec sharp sh -c "apt-get update && apt-get install -y nodejs"
+      install: sudo docker exec sharp sh -c "npm install --build-from-source --unsafe-perm"
+      script: sudo docker exec sharp sh -c "npm test"
+
+    - name: "Linux ARM64v8 (Debian 11, glibc 2.29) - Node.js 14"
+      arch: arm64
+      os: linux
+      dist: bionic
+      language: shell
+      before_install:
+        - sudo docker run -dit --name sharp --volume "${PWD}:/mnt/sharp" --workdir /mnt/sharp arm64v8/debian:bullseye
+        - sudo docker exec sharp sh -c "apt-get update && apt-get install -y build-essential git python3 curl"
+        - sudo docker exec sharp sh -c "curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add -"
+        - sudo docker exec sharp sh -c "echo 'deb https://deb.nodesource.com/node_14.x sid main' >/etc/apt/sources.list.d/nodesource.list"
+        - sudo docker exec sharp sh -c "apt-get update && apt-get install -y nodejs"
+      install: sudo docker exec sharp sh -c "npm install --build-from-source --unsafe-perm"
+      script: sudo docker exec sharp sh -c "npm test"
+
+    - name: "Linux ARM64v8 (Debian 11, glibc 2.29) - Node.js 15"
+      arch: arm64
+      os: linux
+      dist: bionic
+      language: shell
+      before_install:
+        - sudo chown 0.0 ${PWD}
+        - sudo docker run -dit --name sharp --volume "${PWD}:/mnt/sharp" --workdir /mnt/sharp arm64v8/debian:bullseye
+        - sudo docker exec sharp sh -c "apt-get update && apt-get install -y build-essential git python3 curl"
+        - sudo docker exec sharp sh -c "curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add -"
+        - sudo docker exec sharp sh -c "echo 'deb https://deb.nodesource.com/node_15.x sid main' >/etc/apt/sources.list.d/nodesource.list"
+        - sudo docker exec sharp sh -c "apt-get update && apt-get install -y nodejs"
+      install: sudo docker exec sharp sh -c "npm install --build-from-source --unsafe-perm"
+      script: sudo docker exec sharp sh -c "npm test"
+
+    - name: "Linux ARM64v8 (Alpine 3.11, musl 1.1.24) - Node.js 10"
+      arch: arm64
+      os: linux
+      dist: focal
+      language: shell
+      before_install:
+        - sudo docker run -dit --name sharp --volume "${PWD}:/mnt/sharp" --workdir /mnt/sharp node:10-alpine3.11
+        - sudo docker exec sharp sh -c "apk add build-base git python3 --update-cache"
+      install: sudo docker exec sharp sh -c "npm install --build-from-source --unsafe-perm"
+      script: sudo docker exec sharp sh -c "npm test"
+      after_success: "[[ -n $TRAVIS_TAG ]] && sudo docker exec --env prebuild_upload sharp sh -c \"npx prebuild --runtime napi --target 3\""
+
+    - name: "Linux ARM64v8 (Alpine 3.11, musl 1.1.24) - Node.js 12"
+      arch: arm64
+      os: linux
+      dist: focal
+      language: shell
+      before_install:
+        - sudo docker run -dit --name sharp --volume "${PWD}:/mnt/sharp" --workdir /mnt/sharp node:12-alpine3.11
+        - sudo docker exec sharp sh -c "apk add build-base git python3 --update-cache"
+      install: sudo docker exec sharp sh -c "npm install --build-from-source --unsafe-perm"
+      script: sudo docker exec sharp sh -c "npm test"
+
+    - name: "Linux ARM64v8 (Alpine 3.11, musl 1.1.24) - Node.js 14"
+      arch: arm64
+      os: linux
+      dist: focal
+      language: shell
+      before_install:
+        - sudo docker run -dit --name sharp --volume "${PWD}:/mnt/sharp" --workdir /mnt/sharp node:14-alpine3.11
+        - sudo docker exec sharp sh -c "apk add build-base git python3 --update-cache"
+      install: sudo docker exec sharp sh -c "npm install --build-from-source --unsafe-perm"
+      script: sudo docker exec sharp sh -c "npm test"
+
+    - name: "Linux ARM64v8 (Alpine 3.11, musl 1.1.24) - Node.js 15"
+      arch: arm64
+      os: linux
+      dist: focal
+      language: shell
+      before_install:
+        - sudo chown 0.0 ${PWD}
+        - sudo docker run -dit --name sharp --volume "${PWD}:/mnt/sharp" --workdir /mnt/sharp node:15-alpine3.11
+        - sudo docker exec sharp sh -c "apk add build-base git python3 --update-cache"
+      install: sudo docker exec sharp sh -c "npm install --build-from-source --unsafe-perm"
+      script: sudo docker exec sharp sh -c "npm test"
+
+cache:
+  npm: false

README.md

@@ -1,326 +1,114 @@
 # sharp
 
-* [Installation](https://github.com/lovell/sharp#installation)
-* [Usage examples](https://github.com/lovell/sharp#usage-examples)
-* [API](https://github.com/lovell/sharp#api)
-* [Testing](https://github.com/lovell/sharp#testing)
-* [Performance](https://github.com/lovell/sharp#performance)
-* [Licence](https://github.com/lovell/sharp#licence)
+<img src="https://cdn.jsdelivr.net/gh/lovell/sharp@master/docs/image/sharp-logo.svg" width="160" height="160" alt="sharp logo" align="right">
 
-The typical use case for this high speed Node.js module is to convert large images of many formats to smaller, web-friendly JPEG, PNG and WebP images of varying dimensions.
+The typical use case for this high speed Node.js module
+is to convert large images in common formats to
+smaller, web-friendly JPEG, PNG, WebP and AVIF images of varying dimensions.
 
-The performance of JPEG resizing is typically 8x faster than ImageMagick and GraphicsMagick, based mainly on the number of CPU cores available. Everything remains non-blocking thanks to _libuv_ and Promises/A+ are supported.
+Resizing an image is typically 4x-5x faster than using the
+quickest ImageMagick and GraphicsMagick settings
+due to its use of [libvips](https://github.com/libvips/libvips).
 
-This module supports reading and writing images of JPEG, PNG and WebP to and from both Buffer objects and the filesystem. It also supports reading images of many other types from the filesystem via libmagick++ or libgraphicsmagick++ if present.
+Colour spaces, embedded ICC profiles and alpha transparency channels are all handled correctly.
+Lanczos resampling ensures quality is not sacrificed for speed.
 
-When generating JPEG output all metadata is removed and Huffman tables optimised without having to use separate command line tools like [jpegoptim](https://github.com/tjko/jpegoptim) and [jpegtran](http://jpegclub.org/jpegtran/).
+As well as image resizing, operations such as
+rotation, extraction, compositing and gamma correction are available.
 
-Anyone who has used the Node.js bindings for [GraphicsMagick](https://github.com/aheckmann/gm) will find the API similarly fluent.
+Most modern macOS, Windows and Linux systems running Node.js v10+
+do not require any additional install or runtime dependencies.
 
-This module is powered by the blazingly fast [libvips](https://github.com/jcupitt/libvips) image processing library, originally created in 1989 at Birkbeck College and currently maintained by John Cupitt.
+## Documentation
 
-## Installation
+Visit [sharp.pixelplumbing.com](https://sharp.pixelplumbing.com/) for complete
+[installation instructions](https://sharp.pixelplumbing.com/install),
+[API documentation](https://sharp.pixelplumbing.com/api-constructor),
+[benchmark tests](https://sharp.pixelplumbing.com/performance) and
+[changelog](https://sharp.pixelplumbing.com/changelog).
 
-	npm install sharp
+## Examples
 
-### Prerequisites
-
-* Node.js v0.10+
-* [libvips](https://github.com/jcupitt/libvips) v7.38.5+
-
-_libvips_ can take advantage of [liborc](http://code.entropywave.com/orc/) if present. Warning: versions of _liborc_ prior to 0.4.19 suffer [memory leaks](https://github.com/lovell/sharp/issues/21#issuecomment-42367306) and version 0.4.19 suffers [buffer overflows](https://github.com/lovell/sharp/issues/21#issuecomment-44813498).
-
-### Install libvips on Mac OS
-
-	brew install homebrew/science/vips --with-webp --with-graphicsmagick
-
-The _gettext_ dependency of _libvips_ [can lead](https://github.com/lovell/sharp/issues/9) to a `library not found for -lintl` error. If so, please try:
-
-	brew link gettext --force
-
-### Install libvips on Ubuntu Linux
-
-#### Ubuntu 14.x
-
-	sudo apt-get install libvips-dev
-
-#### Ubuntu 13.x
-
-Compiling from source is recommended:
-
-	sudo apt-get install automake build-essential git gobject-introspection gtk-doc-tools libfftw3-dev libglib2.0-dev libjpeg-turbo8-dev libpng12-dev libwebp-dev libtiff5-dev libexif-dev libxml2-dev swig
-	git clone https://github.com/jcupitt/libvips.git
-	cd libvips
-	git checkout 7.38
-	./bootstrap.sh
-	./configure --enable-debug=no --enable-cxx=yes --without-python --without-orc
-	make
-	sudo make install
-	sudo ldconfig
-
-#### Ubuntu 12.x
-
-Requires `libtiff4-dev` instead of `libtiff5-dev` and has [a bug](https://bugs.launchpad.net/ubuntu/+source/libwebp/+bug/1108731) in the libwebp package. Work around these problems by running these commands first:
-
-	sudo add-apt-repository ppa:lyrasis/precise-backports
-	sudo apt-get update
-	sudo apt-get install libtiff4-dev
-
-Then follow Ubuntu 13.x instructions.
-
-## Usage examples
-
-```javascript
-var sharp = require('sharp');
+```sh
+npm install sharp
 ```
 
 ```javascript
-sharp('input.jpg').resize(300, 200).toFile('output.jpg', function(err) {
-  if (err) {
-    throw err;
+const sharp = require('sharp');
+```
+
+### Callback
+
+```javascript
+sharp(inputBuffer)
+  .resize(320, 240)
+  .toFile('output.webp', (err, info) => { ... });
+```
+
+### Promise
+
+```javascript
+sharp('input.jpg')
+  .rotate()
+  .resize(200)
+  .jpeg({ mozjpeg: true })
+  .toBuffer()
+  .then( data => { ... })
+  .catch( err => { ... });
+```
+
+### Async/await
+
+```javascript
+const semiTransparentRedPng = await sharp({
+  create: {
+    width: 48,
+    height: 48,
+    channels: 4,
+    background: { r: 255, g: 0, b: 0, alpha: 0.5 }
   }
-  // output.jpg is a 300 pixels wide and 200 pixels high image
-  // containing a scaled and cropped version of input.jpg
-});
+})
+  .png()
+  .toBuffer();
 ```
 
+### Stream
+
 ```javascript
-sharp('input.jpg').rotate().resize(null, 200).progressive().toBuffer(function(err, outputBuffer) {
-  if (err) {
-    throw err;
-  }
-  // outputBuffer contains 200px high progressive JPEG image data, auto-rotated using EXIF Orientation tag
-});
+const roundedCorners = Buffer.from(
+  '<svg><rect x="0" y="0" width="200" height="200" rx="50" ry="50"/></svg>'
+);
+
+const roundedCornerResizer =
+  sharp()
+    .resize(200, 200)
+    .composite([{
+      input: roundedCorners,
+      blend: 'dest-in'
+    }])
+    .png();
+
+readableStream
+  .pipe(roundedCornerResizer)
+  .pipe(writableStream);
 ```
 
-```javascript
-sharp('input.png').rotate(180).resize(300).sharpen().quality(90).webp().then(function(outputBuffer) {
-  // outputBuffer contains 300px wide, upside down, sharpened, 90% quality WebP image data
-});
-```
+## Contributing
 
-```javascript
-sharp(inputBuffer).resize(200, 300).bicubicInterpolation().embedWhite().toFile('output.tiff').then(function() {
-  // output.tiff is a 200 pixels wide and 300 pixels high image containing a bicubic scaled
-  // version, embedded on a white canvas, of the image data in buffer
-});
-```
+A [guide for contributors](https://github.com/lovell/sharp/blob/master/.github/CONTRIBUTING.md)
+covers reporting bugs, requesting features and submitting code changes.
 
-```javascript
-sharp('input.gif').resize(200, 300).embedBlack().webp(function(err, outputBuffer) {
-  if (err) {
-    throw err;
-  }
-  // outputBuffer contains WebP image data of a 200 pixels wide and 300 pixels high
-  // containing a scaled version, embedded on a black canvas, of input.gif
-});
-```
+[![Test Coverage](https://coveralls.io/repos/lovell/sharp/badge.svg?branch=master)](https://coveralls.io/r/lovell/sharp?branch=master)
+[![N-API v3](https://img.shields.io/badge/N--API-v3-green.svg)](https://nodejs.org/dist/latest/docs/api/n-api.html#n_api_n_api_version_matrix)
 
-```javascript
-sharp(inputBuffer).resize(200, 200).max().jpeg().then(function(outputBuffer) {
-  // outputBuffer contains JPEG image data no wider than 200 pixels and no higher
-  // than 200 pixels regardless of the inputBuffer image dimensions
-});
-```
+## Licensing
 
-## API
-
-### sharp(input)
-
-Constructor to which further methods are chained. `input` can be one of:
-
-* Buffer containing JPEG, PNG or WebP image data, or
-* String containing the filename of an image, with most major formats supported.
-
-### resize(width, [height])
-
-Scale output to `width` x `height`. By default, the resized image is cropped to the exact size specified.
-
-`width` is the Number of pixels wide the resultant image should be. Use `null` or `undefined` to auto-scale the width to match the height.
-
-`height` is the Number of pixels high the resultant image should be. Use `null` or `undefined` to auto-scale the height to match the width.
-
-### crop()
-
-Crop the resized image to the exact size specified, the default behaviour.
-
-### max()
-
-Preserving aspect ratio, resize the image to the maximum width or height specified.
-
-Both `width` and `height` must be provided via `resize` otherwise the behaviour will default to `crop`.
-
-### embedWhite()
-
-Embed the resized image on a white background of the exact size specified.
-
-### embedBlack()
-
-Embed the resized image on a black background of the exact size specified.
-
-### rotate([angle])
-
-Rotate the output image by either an explicit angle or auto-orient based on the EXIF `Orientation` tag. Mirroring is not supported.
-
-`angle`, if present, is a Number with a value of `0`, `90`, `180` or `270`.
-
-Use this method without `angle` to determine the angle from EXIF data.
-
-### withoutEnlargement()
-
-Do not enlarge the output image if the input image width *or* height are already less than the required dimensions.
-
-This is equivalent to GraphicsMagick's `>` geometry option: "change the dimensions of the image only if its width or height exceeds the geometry specification".
-
-### sharpen()
-
-Perform a mild sharpen of the resultant image. This typically reduces performance by 30%.
-
-### bilinearInterpolation()
-
-Use [bilinear interpolation](http://en.wikipedia.org/wiki/Bilinear_interpolation) for image resizing, the default (and fastest) interpolation if none is specified.
-
-### bicubicInterpolation()
-
-Use [bicubic interpolation](http://en.wikipedia.org/wiki/Bicubic_interpolation) for image resizing. This typically reduces performance by 5%.
-
-### nohaloInterpolation()
-
-Use [Nohalo interpolation](http://eprints.soton.ac.uk/268086/) for image resizing. This typically reduces performance by a factor of 2.
-
-### progressive()
-
-Use progressive (interlace) scan for JPEG and PNG output. This typically reduces compression performance by 30% but results in an image that can be rendered sooner when decompressed.
-
-### quality(quality)
-
-The output quality to use for lossy JPEG, WebP and TIFF output formats. The default quality is `80`.
-
-`quality` is a Number between 1 and 100.
-
-### compressionLevel(compressionLevel)
-
-An advanced setting for the _zlib_ compression level of the lossless PNG output format. The default level is `6`.
-
-`compressionLevel` is a Number between -1 and 9.
-
-### sequentialRead()
-
-An advanced setting that switches the libvips access method to `VIPS_ACCESS_SEQUENTIAL`. This will reduce memory usage and can improve performance on some systems.
-
-### toFile(filename, [callback])
-
-`filename` is a String containing the filename to write the image data to. The format is inferred from the extension, with JPEG, PNG, WebP and TIFF supported.
-
-`callback`, if present, is called with a single argument `(err)` containing an error message, if any.
-
-A Promises/A+ promise is returned when `callback` is not provided.
-
-### toBuffer([callback])
-
-Write image data to a Buffer, the format of which will match the input image. JPEG, PNG and WebP are supported.
-
-`callback`, if present, gets two arguments `(err, buffer)` where `err` is an error message, if any, and `buffer` is the resultant image data.
-
-A Promises/A+ promise is returned when `callback` is not provided.
-
-### jpeg([callback])
-
-Write JPEG image data to a Buffer.
-
-`callback`, if present, gets two arguments `(err, buffer)` where `err` is an error message, if any, and `buffer` is the resultant JPEG image data.
-
-A Promises/A+ promise is returned when `callback` is not provided.
-
-### png([callback])
-
-Write PNG image data to a Buffer.
-
-`callback`, if present, gets two arguments `(err, buffer)` where `err` is an error message, if any, and `buffer` is the resultant PNG image data.
-
-A Promises/A+ promise is returned when `callback` is not provided.
-
-### webp([callback])
-
-Write WebP image data to a Buffer.
-
-`callback`, if present, gets two arguments `(err, buffer)` where `err` is an error message, if any, and `buffer` is the resultant WebP image data.
-
-A Promises/A+ promise is returned when `callback` is not provided.
-
-### sharp.cache([limit])
-
-If `limit` is provided, set the (soft) limit of _libvips_ working/cache memory to this value in MB. The default value is 100.
-
-This method always returns cache statistics, useful for determining how much working memory is required for a particular task.
-
-Warnings such as _Application transferred too many scanlines_ are a good indicator you've set this value too low.
-
-```javascript
-var stats = sharp.cache(); // { current: 98, high: 115, limit: 100 }
-sharp.cache(200); // { current: 98, high: 115, limit: 200 }
-sharp.cache(50); // { current: 49, high: 115, limit: 50 }
-```
-
-## Testing
-
-[![Build Status](https://travis-ci.org/lovell/sharp.png?branch=master)](https://travis-ci.org/lovell/sharp)
-
-	npm test
-
-Running the tests requires both ImageMagick and GraphicsMagick plus one of either libmagick++-dev or libgraphicsmagick++.
-
-	brew install imagemagick
-	brew install graphicsmagick
-
-	sudo apt-get install imagemagick graphicsmagick libmagick++-dev
-
-## Performance
-
-### Test environment
-
-* Intel Xeon [L5520](http://ark.intel.com/products/40201/Intel-Xeon-Processor-L5520-8M-Cache-2_26-GHz-5_86-GTs-Intel-QPI) 2.27GHz 8MB cache
-* Ubuntu 13.10
-* libvips 7.38.5
-
-### The contenders
-
-* [imagemagick-native](https://github.com/mash/node-imagemagick-native) - Supports Buffers only and blocks main V8 thread whilst processing.
-* [imagemagick](https://github.com/rsms/node-imagemagick) - Supports filesystem only and "has been unmaintained for a long time".
-* [gm](https://github.com/aheckmann/gm) - Fully featured wrapper around GraphicsMagick.
-* sharp - Caching within libvips disabled to ensure a fair comparison.
-
-### The task
-
-Decompress a 2725x2225 JPEG image, resize and crop to 720x480, then compress to JPEG.
-
-### Results
-
-| Module                | Input  | Output | Ops/sec | Speed-up |
-| :-------------------- | :----- | :----- | ------: | -------: |
-| imagemagick-native    | buffer | buffer |    0.97 |        1 |
-| imagemagick           | file   | file   |    2.49 |      2.6 |
-| gm                    | buffer | file   |    3.72 |      3.8 |
-| gm                    | buffer | buffer |    3.80 |      3.9 |
-| gm                    | file   | file   |    3.67 |      3.8 |
-| gm                    | file   | buffer |    3.67 |      3.8 |
-| sharp                 | buffer | file   |   13.62 |     14.0 |
-| sharp                 | buffer | buffer |   12.43 |     12.8 |
-| sharp                 | file   | file   |   13.02 |     13.4 |
-| sharp                 | file   | buffer |   11.15 |     11.5 |
-| sharp +sharpen        | file   | buffer |   10.26 |     10.6 |
-| sharp +progressive    | file   | buffer |    9.44 |      9.7 |
-| sharp +sequentialRead | file   | buffer |   11.94 |     12.3 |
-
-You can expect much greater performance with caching enabled (default) and using 16+ core machines.
-
-## Licence
-
-Copyright 2013, 2014 Lovell Fuller and Pierre Inglebert
+Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021 Lovell Fuller and contributors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
-You may obtain a copy of the License at [http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0.html)
+You may obtain a copy of the License at
+[https://www.apache.org/licenses/LICENSE-2.0](https://www.apache.org/licenses/LICENSE-2.0)
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,

appveyor.yml

@@ -0,0 +1,18 @@
+os: Visual Studio 2019
+version: "{build}"
+build: off
+platform: x86
+environment:
+  matrix:
+  - nodejs_version: "10"
+    prebuild: true
+  - nodejs_version: "12"
+  - nodejs_version: "14"
+  - nodejs_version: "15"
+install:
+  - ps: Update-NodeJsInstallation (Get-NodeJsLatestBuild $env:nodejs_version)
+  - npm install --build-from-source
+test_script:
+  - npm test
+on_success:
+  - if [%prebuild%] == [true] if [%APPVEYOR_REPO_TAG%] == [true] npx prebuild --runtime napi --target 3

binding.gyp

@@ -1,18 +1,230 @@
 {
+  'variables': {
+    'vips_version': '<!(node -p "require(\'./lib/libvips\').minimumLibvipsVersion")',
+    'sharp_vendor_dir': '<(module_root_dir)/vendor/<(vips_version)'
+  },
   'targets': [{
+    'target_name': 'libvips-cpp',
+    'conditions': [
+      ['OS == "win"', {
+        # Build libvips C++ binding for Windows due to MSVC std library ABI changes
+        'type': 'shared_library',
+        'defines': [
+          'VIPS_CPLUSPLUS_EXPORTS',
+          '_ALLOW_KEYWORD_MACROS'
+        ],
+        'sources': [
+          'src/libvips/cplusplus/VError.cpp',
+          'src/libvips/cplusplus/VConnection.cpp',
+          'src/libvips/cplusplus/VInterpolate.cpp',
+          'src/libvips/cplusplus/VImage.cpp'
+        ],
+        'include_dirs': [
+          '<(sharp_vendor_dir)/include',
+          '<(sharp_vendor_dir)/include/glib-2.0',
+          '<(sharp_vendor_dir)/lib/glib-2.0/include'
+        ],
+        'link_settings': {
+          'library_dirs': ['<(sharp_vendor_dir)/lib'],
+          'libraries': [
+            'libvips.lib',
+            'libglib-2.0.lib',
+            'libgobject-2.0.lib'
+          ],
+        },
+        'configurations': {
+          'Release': {
+            'msvs_settings': {
+              'VCCLCompilerTool': {
+                'ExceptionHandling': 1,
+                'WholeProgramOptimization': 'true'
+              },
+              'VCLibrarianTool': {
+                'AdditionalOptions': [
+                  '/LTCG:INCREMENTAL'
+                ]
+              },
+              'VCLinkerTool': {
+                'ImageHasSafeExceptionHandlers': 'false',
+                'OptimizeReferences': 2,
+                'EnableCOMDATFolding': 2,
+                'LinkIncremental': 1,
+                'AdditionalOptions': [
+                  '/LTCG:INCREMENTAL'
+                ]
+              }
+            },
+            'msvs_disabled_warnings': [
+              4275
+            ]
+          }
+        }
+      }, {
+        # Ignore this target for non-Windows
+        'type': 'none'
+      }]
+    ]
+  }, {
     'target_name': 'sharp',
-    'sources': ['src/sharp.cc'],
+    'defines': [
+      'NAPI_VERSION=3'
+    ],
+    'dependencies': [
+      '<!(node -p "require(\'node-addon-api\').gyp")',
+      'libvips-cpp'
+    ],
     'variables': {
-      'PKG_CONFIG_PATH': '<!(which brew >/dev/null 2>&1 && eval $(brew --env) && echo $PKG_CONFIG_LIBDIR || true):$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig:/usr/lib/pkgconfig'
+      'runtime_link%': 'shared',
+      'conditions': [
+        ['OS != "win"', {
+          'pkg_config_path': '<!(node -p "require(\'./lib/libvips\').pkgConfigPath()")',
+          'use_global_libvips': '<!(node -p "Boolean(require(\'./lib/libvips\').useGlobalLibvips()).toString()")'
+        }, {
+          'pkg_config_path': '',
+          'use_global_libvips': ''
+        }]
+      ]
     },
-    'libraries': [
-      '<!(PKG_CONFIG_PATH="<(PKG_CONFIG_PATH)" pkg-config --libs vips)'
+    'sources': [
+      'src/common.cc',
+      'src/metadata.cc',
+      'src/stats.cc',
+      'src/operations.cc',
+      'src/pipeline.cc',
+      'src/utilities.cc',
+      'src/sharp.cc'
     ],
     'include_dirs': [
-      '<!(PKG_CONFIG_PATH="<(PKG_CONFIG_PATH)" pkg-config --cflags vips glib-2.0)',
-      '<!(node -e "require(\'nan\')")'
+      '<!(node -p "require(\'node-addon-api\').include_dir")',
     ],
-    'cflags': ['-fexceptions', '-pedantic', '-Wall', '-O3'],
-    'cflags_cc': ['-fexceptions', '-pedantic', '-Wall', '-O3']
+    'conditions': [
+      ['use_global_libvips == "true"', {
+        # Use pkg-config for include and lib
+        'include_dirs': ['<!@(PKG_CONFIG_PATH="<(pkg_config_path)" pkg-config --cflags-only-I vips-cpp vips glib-2.0 | sed s\/-I//g)'],
+        'conditions': [
+          ['runtime_link == "static"', {
+            'libraries': ['<!@(PKG_CONFIG_PATH="<(pkg_config_path)" pkg-config --libs --static vips-cpp)']
+          }, {
+            'libraries': ['<!@(PKG_CONFIG_PATH="<(pkg_config_path)" pkg-config --libs vips-cpp)']
+          }],
+          ['OS == "linux"', {
+            'defines': [
+              # Inspect libvips-cpp.so to determine which C++11 ABI version was used and set _GLIBCXX_USE_CXX11_ABI accordingly. This is quite horrible.
+              '_GLIBCXX_USE_CXX11_ABI=<!(if readelf -Ws "$(PKG_CONFIG_PATH="<(pkg_config_path)" pkg-config --variable libdir vips-cpp)/libvips-cpp.so" | c++filt | grep -qF __cxx11;then echo "1";else echo "0";fi)'
+            ]
+          }]
+        ]
+      }, {
+        # Use pre-built libvips stored locally within node_modules
+        'include_dirs': [
+          '<(sharp_vendor_dir)/include',
+          '<(sharp_vendor_dir)/include/glib-2.0',
+          '<(sharp_vendor_dir)/lib/glib-2.0/include'
+        ],
+        'conditions': [
+          ['OS == "win"', {
+            'defines': [
+              '_ALLOW_KEYWORD_MACROS',
+              '_FILE_OFFSET_BITS=64'
+            ],
+            'link_settings': {
+              'library_dirs': ['<(sharp_vendor_dir)/lib'],
+              'libraries': [
+                'libvips.lib',
+                'libglib-2.0.lib',
+                'libgobject-2.0.lib'
+              ]
+            }
+          }],
+          ['OS == "mac"', {
+            'link_settings': {
+              'library_dirs': ['<(sharp_vendor_dir)/lib'],
+              'libraries': [
+                'libvips-cpp.42.dylib'
+              ]
+            },
+            'xcode_settings': {
+              'OTHER_LDFLAGS': [
+                # Ensure runtime linking is relative to sharp.node
+                '-Wl,-rpath,\'@loader_path/../../vendor/<(vips_version)/lib\''
+              ]
+            }
+          }],
+          ['OS == "linux"', {
+            'defines': [
+              '_GLIBCXX_USE_CXX11_ABI=1'
+            ],
+            'link_settings': {
+              'library_dirs': ['<(sharp_vendor_dir)/lib'],
+              'libraries': [
+                '-l:libvips-cpp.so.42'
+              ],
+              'ldflags': [
+                # Ensure runtime linking is relative to sharp.node
+                '-Wl,-s -Wl,--disable-new-dtags -Wl,-rpath=\'$$ORIGIN/../../vendor/<(vips_version)/lib\''
+              ]
+            }
+          }]
+        ]
+      }]
+    ],
+    'cflags_cc': [
+      '-std=c++0x',
+      '-fexceptions',
+      '-Wall',
+      '-O3'
+    ],
+    'xcode_settings': {
+      'CLANG_CXX_LANGUAGE_STANDARD': 'c++11',
+      'MACOSX_DEPLOYMENT_TARGET': '10.9',
+      'GCC_ENABLE_CPP_EXCEPTIONS': 'YES',
+      'GCC_ENABLE_CPP_RTTI': 'YES',
+      'OTHER_CPLUSPLUSFLAGS': [
+        '-fexceptions',
+        '-Wall',
+        '-O3'
+      ]
+    },
+    'configurations': {
+      'Release': {
+        'conditions': [
+          ['OS == "linux"', {
+            'cflags_cc': [
+              '-Wno-cast-function-type'
+            ]
+          }],
+          ['target_arch == "arm"', {
+            'cflags_cc': [
+              '-Wno-psabi'
+            ]
+          }],
+          ['OS == "win"', {
+            'msvs_settings': {
+              'VCCLCompilerTool': {
+                'ExceptionHandling': 1,
+                'WholeProgramOptimization': 'true'
+              },
+              'VCLibrarianTool': {
+                'AdditionalOptions': [
+                  '/LTCG:INCREMENTAL'
+                ]
+              },
+              'VCLinkerTool': {
+                'ImageHasSafeExceptionHandlers': 'false',
+                'OptimizeReferences': 2,
+                'EnableCOMDATFolding': 2,
+                'LinkIncremental': 1,
+                'AdditionalOptions': [
+                  '/LTCG:INCREMENTAL'
+                ]
+              }
+            },
+            'msvs_disabled_warnings': [
+              4275
+            ]
+          }]
+        ]
+      }
+    },
   }]
 }

docs/README.md

@@ -0,0 +1,84 @@
+# sharp
+
+<img src="https://cdn.jsdelivr.net/gh/lovell/sharp@master/docs/image/sharp-logo.svg" width="160" height="160" alt="sharp logo" align="right">
+
+The typical use case for this high speed Node.js module
+is to convert large images in common formats to
+smaller, web-friendly JPEG, PNG, AVIF and WebP images of varying dimensions.
+
+Resizing an image is typically 4x-5x faster than using the
+quickest ImageMagick and GraphicsMagick settings
+due to its use of [libvips](https://github.com/libvips/libvips).
+
+Colour spaces, embedded ICC profiles and alpha transparency channels are all handled correctly.
+Lanczos resampling ensures quality is not sacrificed for speed.
+
+As well as image resizing, operations such as
+rotation, extraction, compositing and gamma correction are available.
+
+Most modern macOS, Windows and Linux systems running Node.js v10+
+do not require any additional install or runtime dependencies.
+
+### Formats
+
+This module supports reading JPEG, PNG, WebP, AVIF, TIFF, GIF and SVG images.
+
+Output images can be in JPEG, PNG, WebP, AVIF and TIFF formats as well as uncompressed raw pixel data.
+
+Streams, Buffer objects and the filesystem can be used for input and output.
+
+A single input Stream can be split into multiple processing pipelines and output Streams.
+
+Deep Zoom image pyramids can be generated,
+suitable for use with "slippy map" tile viewers like
+[OpenSeadragon](https://github.com/openseadragon/openseadragon).
+
+### Fast
+
+This module is powered by the blazingly fast
+[libvips](https://github.com/libvips/libvips) image processing library,
+originally created in 1989 at Birkbeck College
+and currently maintained by a small team led by
+[John Cupitt](https://github.com/jcupitt).
+
+Only small regions of uncompressed image data
+are held in memory and processed at a time,
+taking full advantage of multiple CPU cores and L1/L2/L3 cache.
+
+Everything remains non-blocking thanks to _libuv_,
+no child processes are spawned and Promises/async/await are supported.
+
+### Optimal
+
+The features of `mozjpeg` and `pngquant` can be used
+to optimise the file size of JPEG and PNG images respectively,
+without having to invoke separate `imagemin` processes.
+
+Huffman tables are optimised when generating JPEG output images
+without having to use separate command line tools like
+[jpegoptim](https://github.com/tjko/jpegoptim) and
+[jpegtran](http://jpegclub.org/jpegtran/).
+
+PNG filtering is disabled by default,
+which for diagrams and line art often produces the same result
+as [pngcrush](https://pmt.sourceforge.io/pngcrush/).
+
+### Contributing
+
+A [guide for contributors](https://github.com/lovell/sharp/blob/master/.github/CONTRIBUTING.md)
+covers reporting bugs, requesting features and submitting code changes.
+
+### Licensing
+
+Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021 Lovell Fuller and contributors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+[https://www.apache.org/licenses/LICENSE-2.0](https://www.apache.org/licenses/LICENSE-2.0)
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

docs/api-channel.md

@@ -0,0 +1,120 @@
+<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
+
+## removeAlpha
+
+Remove alpha channel, if any. This is a no-op if the image does not have an alpha channel.
+
+### Examples
+
+```javascript
+sharp('rgba.png')
+  .removeAlpha()
+  .toFile('rgb.png', function(err, info) {
+    // rgb.png is a 3 channel image without an alpha channel
+  });
+```
+
+Returns **Sharp** 
+
+## ensureAlpha
+
+Ensure alpha channel, if missing. The added alpha channel will be fully opaque. This is a no-op if the image already has an alpha channel.
+
+### Examples
+
+```javascript
+sharp('rgb.jpg')
+  .ensureAlpha()
+  .toFile('rgba.png', function(err, info) {
+    // rgba.png is a 4 channel image with a fully opaque alpha channel
+  });
+```
+
+Returns **Sharp** 
+
+**Meta**
+
+-   **since**: 0.21.2
+
+## extractChannel
+
+Extract a single channel from a multi-channel image.
+
+### Parameters
+
+-   `channel` **([number][1] \| [string][2])** zero-indexed channel/band number to extract, or `red`, `green`, `blue` or `alpha`.
+
+### Examples
+
+```javascript
+sharp(input)
+  .extractChannel('green')
+  .toColourspace('b-w')
+  .toFile('green.jpg', function(err, info) {
+    // info.channels === 1
+    // green.jpg is a greyscale image containing the green channel of the input
+   });
+```
+
+-   Throws **[Error][3]** Invalid channel
+
+Returns **Sharp** 
+
+## joinChannel
+
+Join one or more channels to the image.
+The meaning of the added channels depends on the output colourspace, set with `toColourspace()`.
+By default the output image will be web-friendly sRGB, with additional channels interpreted as alpha channels.
+Channel ordering follows vips convention:
+
+-   sRGB: 0: Red, 1: Green, 2: Blue, 3: Alpha.
+-   CMYK: 0: Magenta, 1: Cyan, 2: Yellow, 3: Black, 4: Alpha.
+
+Buffers may be any of the image formats supported by sharp.
+For raw pixel input, the `options` object should contain a `raw` attribute, which follows the format of the attribute of the same name in the `sharp()` constructor.
+
+### Parameters
+
+-   `images` **([Array][4]&lt;([string][2] \| [Buffer][5])> | [string][2] \| [Buffer][5])** one or more images (file paths, Buffers).
+-   `options` **[Object][6]** image options, see `sharp()` constructor.
+
+
+-   Throws **[Error][3]** Invalid parameters
+
+Returns **Sharp** 
+
+## bandbool
+
+Perform a bitwise boolean operation on all input image channels (bands) to produce a single channel output image.
+
+### Parameters
+
+-   `boolOp` **[string][2]** one of `and`, `or` or `eor` to perform that bitwise operation, like the C logic operators `&`, `|` and `^` respectively.
+
+### Examples
+
+```javascript
+sharp('3-channel-rgb-input.png')
+  .bandbool(sharp.bool.and)
+  .toFile('1-channel-output.png', function (err, info) {
+    // The output will be a single channel image where each pixel `P = R & G & B`.
+    // If `I(1,1) = [247, 170, 14] = [0b11110111, 0b10101010, 0b00001111]`
+    // then `O(1,1) = 0b11110111 & 0b10101010 & 0b00001111 = 0b00000010 = 2`.
+  });
+```
+
+-   Throws **[Error][3]** Invalid parameters
+
+Returns **Sharp** 
+
+[1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array
+
+[5]: https://nodejs.org/api/buffer.html
+
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object

docs/api-colour.md

@@ -0,0 +1,87 @@
+<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
+
+## tint
+
+Tint the image using the provided chroma while preserving the image luminance.
+An alpha channel may be present and will be unchanged by the operation.
+
+### Parameters
+
+-   `rgb` **([string][1] \| [Object][2])** parsed by the [color][3] module to extract chroma values.
+
+
+-   Throws **[Error][4]** Invalid parameter
+
+Returns **Sharp** 
+
+## greyscale
+
+Convert to 8-bit greyscale; 256 shades of grey.
+This is a linear operation. If the input image is in a non-linear colour space such as sRGB, use `gamma()` with `greyscale()` for the best results.
+By default the output image will be web-friendly sRGB and contain three (identical) color channels.
+This may be overridden by other sharp operations such as `toColourspace('b-w')`,
+which will produce an output image containing one color channel.
+An alpha channel may be present, and will be unchanged by the operation.
+
+### Parameters
+
+-   `greyscale` **[Boolean][5]**  (optional, default `true`)
+
+Returns **Sharp** 
+
+## grayscale
+
+Alternative spelling of `greyscale`.
+
+### Parameters
+
+-   `grayscale` **[Boolean][5]**  (optional, default `true`)
+
+Returns **Sharp** 
+
+## toColourspace
+
+Set the output colourspace.
+By default output image will be web-friendly sRGB, with additional channels interpreted as alpha channels.
+
+### Parameters
+
+-   `colourspace` **[string][1]?** output colourspace e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...][6]
+
+### Examples
+
+```javascript
+// Output 16 bits per pixel RGB
+await sharp(input)
+ .toColourspace('rgb16')
+ .toFile('16-bpp.png')
+```
+
+-   Throws **[Error][4]** Invalid parameters
+
+Returns **Sharp** 
+
+## toColorspace
+
+Alternative spelling of `toColourspace`.
+
+### Parameters
+
+-   `colorspace` **[string][1]?** output colorspace.
+
+
+-   Throws **[Error][4]** Invalid parameters
+
+Returns **Sharp** 
+
+[1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[3]: https://www.npmjs.org/package/color
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[6]: https://github.com/libvips/libvips/blob/master/libvips/iofuncs/enumtypes.c#L568

docs/api-composite.md

@@ -0,0 +1,86 @@
+<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
+
+## composite
+
+Composite image(s) over the processed (resized, extracted etc.) image.
+
+The images to composite must be the same size or smaller than the processed image.
+If both `top` and `left` options are provided, they take precedence over `gravity`.
+
+The `blend` option can be one of `clear`, `source`, `over`, `in`, `out`, `atop`,
+`dest`, `dest-over`, `dest-in`, `dest-out`, `dest-atop`,
+`xor`, `add`, `saturate`, `multiply`, `screen`, `overlay`, `darken`, `lighten`,
+`colour-dodge`, `color-dodge`, `colour-burn`,`color-burn`,
+`hard-light`, `soft-light`, `difference`, `exclusion`.
+
+More information about blend modes can be found at
+[https://libvips.github.io/libvips/API/current/libvips-conversion.html#VipsBlendMode][1]
+and [https://www.cairographics.org/operators/][2]
+
+### Parameters
+
+-   `images` **[Array][3]&lt;[Object][4]>** Ordered list of images to composite
+    -   `images[].input` **([Buffer][5] \| [String][6])?** Buffer containing image data, String containing the path to an image file, or Create object (see below)
+        -   `images[].input.create` **[Object][4]?** describes a blank overlay to be created.
+            -   `images[].input.create.width` **[Number][7]?** 
+            -   `images[].input.create.height` **[Number][7]?** 
+            -   `images[].input.create.channels` **[Number][7]?** 3-4
+            -   `images[].input.create.background` **([String][6] \| [Object][4])?** parsed by the [color][8] module to extract values for red, green, blue and alpha.
+    -   `images[].blend` **[String][6]** how to blend this image with the image below. (optional, default `'over'`)
+    -   `images[].gravity` **[String][6]** gravity at which to place the overlay. (optional, default `'centre'`)
+    -   `images[].top` **[Number][7]?** the pixel offset from the top edge.
+    -   `images[].left` **[Number][7]?** the pixel offset from the left edge.
+    -   `images[].tile` **[Boolean][9]** set to true to repeat the overlay image across the entire image with the given `gravity`. (optional, default `false`)
+    -   `images[].premultiplied` **[Boolean][9]** set to true to avoid premultipling the image below. Equivalent to the `--premultiplied` vips option. (optional, default `false`)
+    -   `images[].density` **[Number][7]** number representing the DPI for vector overlay image. (optional, default `72`)
+    -   `images[].raw` **[Object][4]?** describes overlay when using raw pixel data.
+        -   `images[].raw.width` **[Number][7]?** 
+        -   `images[].raw.height` **[Number][7]?** 
+        -   `images[].raw.channels` **[Number][7]?** 
+
+### Examples
+
+```javascript
+sharp('input.png')
+  .rotate(180)
+  .resize(300)
+  .flatten( { background: '#ff6600' } )
+  .composite([{ input: 'overlay.png', gravity: 'southeast' }])
+  .sharpen()
+  .withMetadata()
+  .webp( { quality: 90 } )
+  .toBuffer()
+  .then(function(outputBuffer) {
+    // outputBuffer contains upside down, 300px wide, alpha channel flattened
+    // onto orange background, composited with overlay.png with SE gravity,
+    // sharpened, with metadata, 90% quality WebP image data. Phew!
+  });
+```
+
+-   Throws **[Error][10]** Invalid parameters
+
+Returns **Sharp** 
+
+**Meta**
+
+-   **since**: 0.22.0
+
+[1]: https://libvips.github.io/libvips/API/current/libvips-conversion.html#VipsBlendMode
+
+[2]: https://www.cairographics.org/operators/
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[5]: https://nodejs.org/api/buffer.html
+
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[8]: https://www.npmjs.org/package/color
+
+[9]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[10]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error

docs/api-constructor.md

@@ -0,0 +1,214 @@
+<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
+
+## Sharp
+
+Constructor factory to create an instance of `sharp`, to which further methods are chained.
+
+JPEG, PNG, WebP, AVIF or TIFF format image data can be streamed out from this object.
+When using Stream based output, derived attributes are available from the `info` event.
+
+Non-critical problems encountered during processing are emitted as `warning` events.
+
+Implements the [stream.Duplex][1] class.
+
+### Parameters
+
+-   `input` **([Buffer][2] \| [Uint8Array][3] \| [Uint8ClampedArray][4] \| [string][5])?** if present, can be
+     a Buffer / Uint8Array / Uint8ClampedArray containing JPEG, PNG, WebP, AVIF, GIF, SVG, TIFF or raw pixel image data, or
+     a String containing the filesystem path to an JPEG, PNG, WebP, AVIF, GIF, SVG or TIFF image file.
+     JPEG, PNG, WebP, AVIF, GIF, SVG, TIFF or raw pixel image data can be streamed into the object when not present.
+-   `options` **[Object][6]?** if present, is an Object with optional attributes.
+    -   `options.failOnError` **[boolean][7]** by default halt processing and raise an error when loading invalid images.
+         Set this flag to `false` if you'd rather apply a "best effort" to decode images, even if the data is corrupt or invalid. (optional, default `true`)
+    -   `options.limitInputPixels` **([number][8] \| [boolean][7])** Do not process input images where the number of pixels
+         (width x height) exceeds this limit. Assumes image dimensions contained in the input metadata can be trusted.
+         An integral Number of pixels, zero or false to remove limit, true to use default limit of 268402689 (0x3FFF x 0x3FFF). (optional, default `268402689`)
+    -   `options.sequentialRead` **[boolean][7]** Set this to `true` to use sequential rather than random access where possible.
+         This can reduce memory usage and might improve performance on some systems. (optional, default `false`)
+    -   `options.density` **[number][8]** number representing the DPI for vector images in the range 1 to 100000. (optional, default `72`)
+    -   `options.pages` **[number][8]** number of pages to extract for multi-page input (GIF, WebP, AVIF, TIFF, PDF), use -1 for all pages. (optional, default `1`)
+    -   `options.page` **[number][8]** page number to start extracting from for multi-page input (GIF, WebP, AVIF, TIFF, PDF), zero based. (optional, default `0`)
+    -   `options.level` **[number][8]** level to extract from a multi-level input (OpenSlide), zero based. (optional, default `0`)
+    -   `options.animated` **[boolean][7]** Set to `true` to read all frames/pages of an animated image (equivalent of setting `pages` to `-1`). (optional, default `false`)
+    -   `options.raw` **[Object][6]?** describes raw pixel input image data. See `raw()` for pixel ordering.
+        -   `options.raw.width` **[number][8]?** integral number of pixels wide.
+        -   `options.raw.height` **[number][8]?** integral number of pixels high.
+        -   `options.raw.channels` **[number][8]?** integral number of channels, between 1 and 4.
+    -   `options.create` **[Object][6]?** describes a new image to be created.
+        -   `options.create.width` **[number][8]?** integral number of pixels wide.
+        -   `options.create.height` **[number][8]?** integral number of pixels high.
+        -   `options.create.channels` **[number][8]?** integral number of channels, either 3 (RGB) or 4 (RGBA).
+        -   `options.create.background` **([string][5] \| [Object][6])?** parsed by the [color][9] module to extract values for red, green, blue and alpha.
+        -   `options.create.noise` **[Object][6]?** describes a noise to be created.
+            -   `options.create.noise.type` **[string][5]?** type of generated noise, currently only `gaussian` is supported.
+            -   `options.create.noise.mean` **[number][8]?** mean of pixels in generated noise.
+            -   `options.create.noise.sigma` **[number][8]?** standard deviation of pixels in generated noise.
+
+### Examples
+
+```javascript
+sharp('input.jpg')
+  .resize(300, 200)
+  .toFile('output.jpg', function(err) {
+    // output.jpg is a 300 pixels wide and 200 pixels high image
+    // containing a scaled and cropped version of input.jpg
+  });
+```
+
+```javascript
+// Read image data from readableStream,
+// resize to 300 pixels wide,
+// emit an 'info' event with calculated dimensions
+// and finally write image data to writableStream
+var transformer = sharp()
+  .resize(300)
+  .on('info', function(info) {
+    console.log('Image height is ' + info.height);
+  });
+readableStream.pipe(transformer).pipe(writableStream);
+```
+
+```javascript
+// Create a blank 300x200 PNG image of semi-transluent red pixels
+sharp({
+  create: {
+    width: 300,
+    height: 200,
+    channels: 4,
+    background: { r: 255, g: 0, b: 0, alpha: 0.5 }
+  }
+})
+.png()
+.toBuffer()
+.then( ... );
+```
+
+```javascript
+// Convert an animated GIF to an animated WebP
+await sharp('in.gif', { animated: true }).toFile('out.webp');
+```
+
+```javascript
+// Read a raw array of pixels and save it to a png
+const input = Uint8Array.from([255, 255, 255, 0, 0, 0]); // or Uint8ClampedArray
+const image = sharp(input, {
+  // because the input does not contain its dimensions or how many channels it has
+  // we need to specify it in the constructor options
+  raw: {
+    width: 2,
+    height: 1,
+    channels: 3
+  }
+});
+await image.toFile('my-two-pixels.png');
+```
+
+```javascript
+// Generate RGB Gaussian noise
+await sharp({
+  create: {
+    width: 300,
+    height: 200,
+    channels: 3,
+    noise: {
+      type: 'gaussian',
+      mean: 128,
+      sigma: 30
+    }
+ }
+}).toFile('noise.png');
+```
+
+-   Throws **[Error][10]** Invalid parameters
+
+Returns **[Sharp][11]** 
+
+## clone
+
+Take a "snapshot" of the Sharp instance, returning a new instance.
+Cloned instances inherit the input of their parent instance.
+This allows multiple output Streams and therefore multiple processing pipelines to share a single input Stream.
+
+### Examples
+
+```javascript
+const pipeline = sharp().rotate();
+pipeline.clone().resize(800, 600).pipe(firstWritableStream);
+pipeline.clone().extract({ left: 20, top: 20, width: 100, height: 100 }).pipe(secondWritableStream);
+readableStream.pipe(pipeline);
+// firstWritableStream receives auto-rotated, resized readableStream
+// secondWritableStream receives auto-rotated, extracted region of readableStream
+```
+
+```javascript
+// Create a pipeline that will download an image, resize it and format it to different files
+// Using Promises to know when the pipeline is complete
+const fs = require("fs");
+const got = require("got");
+const sharpStream = sharp({
+  failOnError: false
+});
+
+const promises = [];
+
+promises.push(
+  sharpStream
+    .clone()
+    .jpeg({ quality: 100 })
+    .toFile("originalFile.jpg")
+);
+
+promises.push(
+  sharpStream
+    .clone()
+    .resize({ width: 500 })
+    .jpeg({ quality: 80 })
+    .toFile("optimized-500.jpg")
+);
+
+promises.push(
+  sharpStream
+    .clone()
+    .resize({ width: 500 })
+    .webp({ quality: 80 })
+    .toFile("optimized-500.webp")
+);
+
+// https://github.com/sindresorhus/got#gotstreamurl-options
+got.stream("https://www.example.com/some-file.jpg").pipe(sharpStream);
+
+Promise.all(promises)
+  .then(res => { console.log("Done!", res); })
+  .catch(err => {
+    console.error("Error processing files, let's clean it up", err);
+    try {
+      fs.unlinkSync("originalFile.jpg");
+      fs.unlinkSync("optimized-500.jpg");
+      fs.unlinkSync("optimized-500.webp");
+    } catch (e) {}
+  });
+```
+
+Returns **[Sharp][11]** 
+
+[1]: http://nodejs.org/api/stream.html#stream_class_stream_duplex
+
+[2]: https://nodejs.org/api/buffer.html
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[8]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[9]: https://www.npmjs.org/package/color
+
+[10]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[11]: #sharp

docs/api-input.md

@@ -0,0 +1,109 @@
+<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
+
+## metadata
+
+Fast access to (uncached) image metadata without decoding any compressed image data.
+A `Promise` is returned when `callback` is not provided.
+
+-   `format`: Name of decoder used to decompress image data e.g. `jpeg`, `png`, `webp`, `gif`, `svg`
+-   `size`: Total size of image in bytes, for Stream and Buffer input only
+-   `width`: Number of pixels wide (EXIF orientation is not taken into consideration)
+-   `height`: Number of pixels high (EXIF orientation is not taken into consideration)
+-   `space`: Name of colour space interpretation e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...][1]
+-   `channels`: Number of bands e.g. `3` for sRGB, `4` for CMYK
+-   `depth`: Name of pixel depth format e.g. `uchar`, `char`, `ushort`, `float` [...][2]
+-   `density`: Number of pixels per inch (DPI), if present
+-   `chromaSubsampling`: String containing JPEG chroma subsampling, `4:2:0` or `4:4:4` for RGB, `4:2:0:4` or `4:4:4:4` for CMYK
+-   `isProgressive`: Boolean indicating whether the image is interlaced using a progressive scan
+-   `pages`: Number of pages/frames contained within the image, with support for TIFF, HEIF, PDF, animated GIF and animated WebP
+-   `pageHeight`: Number of pixels high each page in a multi-page image will be.
+-   `loop`: Number of times to loop an animated image, zero refers to a continuous loop.
+-   `delay`: Delay in ms between each page in an animated image, provided as an array of integers.
+-   `pagePrimary`: Number of the primary page in a HEIF image
+-   `levels`: Details of each level in a multi-level image provided as an array of objects, requires libvips compiled with support for OpenSlide
+-   `hasProfile`: Boolean indicating the presence of an embedded ICC profile
+-   `hasAlpha`: Boolean indicating the presence of an alpha transparency channel
+-   `orientation`: Number value of the EXIF Orientation header, if present
+-   `exif`: Buffer containing raw EXIF data, if present
+-   `icc`: Buffer containing raw [ICC][3] profile data, if present
+-   `iptc`: Buffer containing raw IPTC data, if present
+-   `xmp`: Buffer containing raw XMP data, if present
+-   `tifftagPhotoshop`: Buffer containing raw TIFFTAG_PHOTOSHOP data, if present
+
+### Parameters
+
+-   `callback` **[Function][4]?** called with the arguments `(err, metadata)`
+
+### Examples
+
+```javascript
+const image = sharp(inputJpg);
+image
+  .metadata()
+  .then(function(metadata) {
+    return image
+      .resize(Math.round(metadata.width / 2))
+      .webp()
+      .toBuffer();
+  })
+  .then(function(data) {
+    // data contains a WebP image half the width and height of the original JPEG
+  });
+```
+
+Returns **([Promise][5]&lt;[Object][6]> | Sharp)** 
+
+## stats
+
+Access to pixel-derived image statistics for every channel in the image.
+A `Promise` is returned when `callback` is not provided.
+
+-   `channels`: Array of channel statistics for each channel in the image. Each channel statistic contains
+    -   `min` (minimum value in the channel)
+    -   `max` (maximum value in the channel)
+    -   `sum` (sum of all values in a channel)
+    -   `squaresSum` (sum of squared values in a channel)
+    -   `mean` (mean of the values in a channel)
+    -   `stdev` (standard deviation for the values in a channel)
+    -   `minX` (x-coordinate of one of the pixel where the minimum lies)
+    -   `minY` (y-coordinate of one of the pixel where the minimum lies)
+    -   `maxX` (x-coordinate of one of the pixel where the maximum lies)
+    -   `maxY` (y-coordinate of one of the pixel where the maximum lies)
+-   `isOpaque`: Is the image fully opaque? Will be `true` if the image has no alpha channel or if every pixel is fully opaque.
+-   `entropy`: Histogram-based estimation of greyscale entropy, discarding alpha channel if any (experimental)
+-   `sharpness`: Estimation of greyscale sharpness based on the standard deviation of a Laplacian convolution, discarding alpha channel if any (experimental)
+-   `dominant`: Object containing most dominant sRGB colour based on a 4096-bin 3D histogram (experimental)
+
+### Parameters
+
+-   `callback` **[Function][4]?** called with the arguments `(err, stats)`
+
+### Examples
+
+```javascript
+const image = sharp(inputJpg);
+image
+  .stats()
+  .then(function(stats) {
+     // stats contains the channel-wise statistics array and the isOpaque value
+  });
+```
+
+```javascript
+const { entropy, sharpness, dominant } = await sharp(input).stats();
+const { r, g, b } = dominant;
+```
+
+Returns **[Promise][5]&lt;[Object][6]>** 
+
+[1]: https://libvips.github.io/libvips/API/current/VipsImage.html#VipsInterpretation
+
+[2]: https://libvips.github.io/libvips/API/current/VipsImage.html#VipsBandFormat
+
+[3]: https://www.npmjs.com/package/icc
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise
+
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object

docs/api-operation.md

@@ -0,0 +1,409 @@
+<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
+
+## rotate
+
+Rotate the output image by either an explicit angle
+or auto-orient based on the EXIF `Orientation` tag.
+
+If an angle is provided, it is converted to a valid positive degree rotation.
+For example, `-450` will produce a 270deg rotation.
+
+When rotating by an angle other than a multiple of 90,
+the background colour can be provided with the `background` option.
+
+If no angle is provided, it is determined from the EXIF data.
+Mirroring is supported and may infer the use of a flip operation.
+
+The use of `rotate` implies the removal of the EXIF `Orientation` tag, if any.
+
+Method order is important when both rotating and extracting regions,
+for example `rotate(x).extract(y)` will produce a different result to `extract(y).rotate(x)`.
+
+### Parameters
+
+-   `angle` **[number][1]** angle of rotation. (optional, default `auto`)
+-   `options` **[Object][2]?** if present, is an Object with optional attributes.
+    -   `options.background` **([string][3] \| [Object][2])** parsed by the [color][4] module to extract values for red, green, blue and alpha. (optional, default `"#000000"`)
+
+### Examples
+
+```javascript
+const pipeline = sharp()
+  .rotate()
+  .resize(null, 200)
+  .toBuffer(function (err, outputBuffer, info) {
+    // outputBuffer contains 200px high JPEG image data,
+    // auto-rotated using EXIF Orientation tag
+    // info.width and info.height contain the dimensions of the resized image
+  });
+readableStream.pipe(pipeline);
+```
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+## flip
+
+Flip the image about the vertical Y axis. This always occurs after rotation, if any.
+The use of `flip` implies the removal of the EXIF `Orientation` tag, if any.
+
+### Parameters
+
+-   `flip` **[Boolean][6]**  (optional, default `true`)
+
+Returns **Sharp** 
+
+## flop
+
+Flop the image about the horizontal X axis. This always occurs after rotation, if any.
+The use of `flop` implies the removal of the EXIF `Orientation` tag, if any.
+
+### Parameters
+
+-   `flop` **[Boolean][6]**  (optional, default `true`)
+
+Returns **Sharp** 
+
+## affine
+
+Perform an affine transform on an image. This operation will always occur after resizing, extraction and rotation, if any.
+
+You must provide an array of length 4 or a 2x2 affine transformation matrix.
+By default, new pixels are filled with a black background. You can provide a background color with the `background` option.
+A particular interpolator may also be specified. Set the `interpolator` option to an attribute of the `sharp.interpolator` Object e.g. `sharp.interpolator.nohalo`.
+
+In the case of a 2x2 matrix, the transform is:
+
+-   X = `matrix[0, 0]` \* (x + `idx`) + `matrix[0, 1]` \* (y + `idy`) + `odx`
+-   Y = `matrix[1, 0]` \* (x + `idx`) + `matrix[1, 1]` \* (y + `idy`) + `ody`
+
+where:
+
+-   x and y are the coordinates in input image.
+-   X and Y are the coordinates in output image.
+-   (0,0) is the upper left corner.
+
+### Parameters
+
+-   `matrix` **([Array][7]&lt;[Array][7]&lt;[number][1]>> | [Array][7]&lt;[number][1]>)** affine transformation matrix
+-   `options` **[Object][2]?** if present, is an Object with optional attributes.
+    -   `options.background` **([String][3] \| [Object][2])** parsed by the [color][4] module to extract values for red, green, blue and alpha. (optional, default `"#000000"`)
+    -   `options.idx` **[Number][1]** input horizontal offset (optional, default `0`)
+    -   `options.idy` **[Number][1]** input vertical offset (optional, default `0`)
+    -   `options.odx` **[Number][1]** output horizontal offset (optional, default `0`)
+    -   `options.ody` **[Number][1]** output vertical offset (optional, default `0`)
+    -   `options.interpolator` **[String][3]** interpolator (optional, default `sharp.interpolators.bicubic`)
+
+### Examples
+
+```javascript
+const pipeline = sharp()
+  .affine([[1, 0.3], [0.1, 0.7]], {
+     background: 'white',
+     interpolate: sharp.interpolators.nohalo
+  })
+  .toBuffer((err, outputBuffer, info) => {
+     // outputBuffer contains the transformed image
+     // info.width and info.height contain the new dimensions
+  });
+
+inputStream
+  .pipe(pipeline);
+```
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+**Meta**
+
+-   **since**: 0.27.0
+
+## sharpen
+
+Sharpen the image.
+When used without parameters, performs a fast, mild sharpen of the output image.
+When a `sigma` is provided, performs a slower, more accurate sharpen of the L channel in the LAB colour space.
+Separate control over the level of sharpening in "flat" and "jagged" areas is available.
+
+### Parameters
+
+-   `sigma` **[number][1]?** the sigma of the Gaussian mask, where `sigma = 1 + radius / 2`.
+-   `flat` **[number][1]** the level of sharpening to apply to "flat" areas. (optional, default `1.0`)
+-   `jagged` **[number][1]** the level of sharpening to apply to "jagged" areas. (optional, default `2.0`)
+
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+## median
+
+Apply median filter.
+When used without parameters the default window is 3x3.
+
+### Parameters
+
+-   `size` **[number][1]** square mask size: size x size (optional, default `3`)
+
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+## blur
+
+Blur the image.
+When used without parameters, performs a fast, mild blur of the output image.
+When a `sigma` is provided, performs a slower, more accurate Gaussian blur.
+
+### Parameters
+
+-   `sigma` **[number][1]?** a value between 0.3 and 1000 representing the sigma of the Gaussian mask, where `sigma = 1 + radius / 2`.
+
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+## flatten
+
+Merge alpha transparency channel, if any, with a background, then remove the alpha channel.
+
+### Parameters
+
+-   `options` **[Object][2]?** 
+    -   `options.background` **([string][3] \| [Object][2])** background colour, parsed by the [color][4] module, defaults to black. (optional, default `{r:0,g:0,b:0}`)
+
+### Examples
+
+```javascript
+await sharp(rgbaInput)
+  .flatten('#F0A703')
+  .toBuffer();
+```
+
+Returns **Sharp** 
+
+## gamma
+
+Apply a gamma correction by reducing the encoding (darken) pre-resize at a factor of `1/gamma`
+then increasing the encoding (brighten) post-resize at a factor of `gamma`.
+This can improve the perceived brightness of a resized image in non-linear colour spaces.
+JPEG and WebP input images will not take advantage of the shrink-on-load performance optimisation
+when applying a gamma correction.
+
+Supply a second argument to use a different output gamma value, otherwise the first value is used in both cases.
+
+### Parameters
+
+-   `gamma` **[number][1]** value between 1.0 and 3.0. (optional, default `2.2`)
+-   `gammaOut` **[number][1]?** value between 1.0 and 3.0. (optional, defaults to same as `gamma`)
+
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+## negate
+
+Produce the "negative" of the image.
+
+### Parameters
+
+-   `negate` **[Boolean][6]**  (optional, default `true`)
+
+Returns **Sharp** 
+
+## normalise
+
+Enhance output image contrast by stretching its luminance to cover the full dynamic range.
+
+### Parameters
+
+-   `normalise` **[Boolean][6]**  (optional, default `true`)
+
+Returns **Sharp** 
+
+## normalize
+
+Alternative spelling of normalise.
+
+### Parameters
+
+-   `normalize` **[Boolean][6]**  (optional, default `true`)
+
+Returns **Sharp** 
+
+## convolve
+
+Convolve the image with the specified kernel.
+
+### Parameters
+
+-   `kernel` **[Object][2]** 
+    -   `kernel.width` **[number][1]** width of the kernel in pixels.
+    -   `kernel.height` **[number][1]** width of the kernel in pixels.
+    -   `kernel.kernel` **[Array][7]&lt;[number][1]>** Array of length `width*height` containing the kernel values.
+    -   `kernel.scale` **[number][1]** the scale of the kernel in pixels. (optional, default `sum`)
+    -   `kernel.offset` **[number][1]** the offset of the kernel in pixels. (optional, default `0`)
+
+### Examples
+
+```javascript
+sharp(input)
+  .convolve({
+    width: 3,
+    height: 3,
+    kernel: [-1, 0, 1, -2, 0, 2, -1, 0, 1]
+  })
+  .raw()
+  .toBuffer(function(err, data, info) {
+    // data contains the raw pixel data representing the convolution
+    // of the input image with the horizontal Sobel operator
+  });
+```
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+## threshold
+
+Any pixel value greater than or equal to the threshold value will be set to 255, otherwise it will be set to 0.
+
+### Parameters
+
+-   `threshold` **[number][1]** a value in the range 0-255 representing the level at which the threshold will be applied. (optional, default `128`)
+-   `options` **[Object][2]?** 
+    -   `options.greyscale` **[Boolean][6]** convert to single channel greyscale. (optional, default `true`)
+    -   `options.grayscale` **[Boolean][6]** alternative spelling for greyscale. (optional, default `true`)
+
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+## boolean
+
+Perform a bitwise boolean operation with operand image.
+
+This operation creates an output image where each pixel is the result of
+the selected bitwise boolean `operation` between the corresponding pixels of the input images.
+
+### Parameters
+
+-   `operand` **([Buffer][8] \| [string][3])** Buffer containing image data or string containing the path to an image file.
+-   `operator` **[string][3]** one of `and`, `or` or `eor` to perform that bitwise operation, like the C logic operators `&`, `|` and `^` respectively.
+-   `options` **[Object][2]?** 
+    -   `options.raw` **[Object][2]?** describes operand when using raw pixel data.
+        -   `options.raw.width` **[number][1]?** 
+        -   `options.raw.height` **[number][1]?** 
+        -   `options.raw.channels` **[number][1]?** 
+
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+## linear
+
+Apply the linear formula a \* input + b to the image (levels adjustment)
+
+### Parameters
+
+-   `a` **[number][1]** multiplier (optional, default `1.0`)
+-   `b` **[number][1]** offset (optional, default `0.0`)
+
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+## recomb
+
+Recomb the image with the specified matrix.
+
+### Parameters
+
+-   `inputMatrix` **[Array][7]&lt;[Array][7]&lt;[number][1]>>** 3x3 Recombination matrix
+
+### Examples
+
+```javascript
+sharp(input)
+  .recomb([
+   [0.3588, 0.7044, 0.1368],
+   [0.2990, 0.5870, 0.1140],
+   [0.2392, 0.4696, 0.0912],
+  ])
+  .raw()
+  .toBuffer(function(err, data, info) {
+    // data contains the raw pixel data after applying the recomb
+    // With this example input, a sepia filter has been applied
+  });
+```
+
+-   Throws **[Error][5]** Invalid parameters
+
+Returns **Sharp** 
+
+**Meta**
+
+-   **since**: 0.21.1
+
+## modulate
+
+Transforms the image using brightness, saturation and hue rotation.
+
+### Parameters
+
+-   `options` **[Object][2]?** 
+    -   `options.brightness` **[number][1]?** Brightness multiplier
+    -   `options.saturation` **[number][1]?** Saturation multiplier
+    -   `options.hue` **[number][1]?** Degrees for hue rotation
+
+### Examples
+
+```javascript
+sharp(input)
+  .modulate({
+    brightness: 2 // increase lightness by a factor of 2
+  });
+
+sharp(input)
+  .modulate({
+    hue: 180 // hue-rotate by 180 degrees
+  });
+
+// decreate brightness and saturation while also hue-rotating by 90 degrees
+sharp(input)
+  .modulate({
+    brightness: 0.5,
+    saturation: 0.5,
+    hue: 90
+  });
+```
+
+Returns **Sharp** 
+
+**Meta**
+
+-   **since**: 0.22.1
+
+[1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[4]: https://www.npmjs.org/package/color
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array
+
+[8]: https://nodejs.org/api/buffer.html

docs/api-output.md

@@ -0,0 +1,470 @@
+<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
+
+## toFile
+
+Write output image data to a file.
+
+If an explicit output format is not selected, it will be inferred from the extension,
+with JPEG, PNG, WebP, AVIF, TIFF, DZI, and libvips' V format supported.
+Note that raw pixel data is only supported for buffer output.
+
+By default all metadata will be removed, which includes EXIF-based orientation.
+See [withMetadata][1] for control over this.
+
+A `Promise` is returned when `callback` is not provided.
+
+### Parameters
+
+-   `fileOut` **[string][2]** the path to write the image data to.
+-   `callback` **[Function][3]?** called on completion with two arguments `(err, info)`.
+    `info` contains the output image `format`, `size` (bytes), `width`, `height`,
+    `channels` and `premultiplied` (indicating if premultiplication was used).
+    When using a crop strategy also contains `cropOffsetLeft` and `cropOffsetTop`.
+
+### Examples
+
+```javascript
+sharp(input)
+  .toFile('output.png', (err, info) => { ... });
+```
+
+```javascript
+sharp(input)
+  .toFile('output.png')
+  .then(info => { ... })
+  .catch(err => { ... });
+```
+
+-   Throws **[Error][4]** Invalid parameters
+
+Returns **[Promise][5]&lt;[Object][6]>** when no callback is provided
+
+## toBuffer
+
+Write output to a Buffer.
+JPEG, PNG, WebP, AVIF, TIFF and raw pixel data output are supported.
+
+If no explicit format is set, the output format will match the input image, except GIF and SVG input which become PNG output.
+
+By default all metadata will be removed, which includes EXIF-based orientation.
+See [withMetadata][1] for control over this.
+
+`callback`, if present, gets three arguments `(err, data, info)` where:
+
+-   `err` is an error, if any.
+-   `data` is the output image data.
+-   `info` contains the output image `format`, `size` (bytes), `width`, `height`,
+    `channels` and `premultiplied` (indicating if premultiplication was used).
+    When using a crop strategy also contains `cropOffsetLeft` and `cropOffsetTop`.
+
+A `Promise` is returned when `callback` is not provided.
+
+### Parameters
+
+-   `options` **[Object][6]?** 
+    -   `options.resolveWithObject` **[boolean][7]?** Resolve the Promise with an Object containing `data` and `info` properties instead of resolving only with `data`.
+-   `callback` **[Function][3]?** 
+
+### Examples
+
+```javascript
+sharp(input)
+  .toBuffer((err, data, info) => { ... });
+```
+
+```javascript
+sharp(input)
+  .toBuffer()
+  .then(data => { ... })
+  .catch(err => { ... });
+```
+
+```javascript
+sharp(input)
+  .toBuffer({ resolveWithObject: true })
+  .then(({ data, info }) => { ... })
+  .catch(err => { ... });
+```
+
+```javascript
+const { data, info } = await sharp('my-image.jpg')
+  // output the raw pixels
+  .raw()
+  .toBuffer({ resolveWithObject: true });
+
+// create a more type safe way to work with the raw pixel data
+// this will not copy the data, instead it will change `data`s underlying ArrayBuffer
+// so `data` and `pixelArray` point to the same memory location
+const pixelArray = new Uint8ClampedArray(data.buffer);
+
+// When you are done changing the pixelArray, sharp takes the `pixelArray` as an input
+const { width, height, channels } = info;
+await sharp(pixelArray, { raw: { width, height, channels } })
+  .toFile('my-changed-image.jpg');
+```
+
+Returns **[Promise][5]&lt;[Buffer][8]>** when no callback is provided
+
+## withMetadata
+
+Include all metadata (EXIF, XMP, IPTC) from the input image in the output image.
+This will also convert to and add a web-friendly sRGB ICC profile unless a custom
+output profile is provided.
+
+The default behaviour, when `withMetadata` is not used, is to convert to the device-independent
+sRGB colour space and strip all metadata, including the removal of any ICC profile.
+
+### Parameters
+
+-   `options` **[Object][6]?** 
+    -   `options.orientation` **[number][9]?** value between 1 and 8, used to update the EXIF `Orientation` tag.
+    -   `options.icc` **[string][2]?** filesystem path to output ICC profile, defaults to sRGB.
+
+### Examples
+
+```javascript
+sharp('input.jpg')
+  .withMetadata()
+  .toFile('output-with-metadata.jpg')
+  .then(info => { ... });
+```
+
+-   Throws **[Error][4]** Invalid parameters
+
+Returns **Sharp** 
+
+## toFormat
+
+Force output to a given format.
+
+### Parameters
+
+-   `format` **([string][2] \| [Object][6])** as a string or an Object with an 'id' attribute
+-   `options` **[Object][6]** output options
+
+### Examples
+
+```javascript
+// Convert any input to PNG output
+const data = await sharp(input)
+  .toFormat('png')
+  .toBuffer();
+```
+
+-   Throws **[Error][4]** unsupported format or options
+
+Returns **Sharp** 
+
+## jpeg
+
+Use these JPEG options for output image.
+
+### Parameters
+
+-   `options` **[Object][6]?** output options
+    -   `options.quality` **[number][9]** quality, integer 1-100 (optional, default `80`)
+    -   `options.progressive` **[boolean][7]** use progressive (interlace) scan (optional, default `false`)
+    -   `options.chromaSubsampling` **[string][2]** set to '4:4:4' to prevent chroma subsampling otherwise defaults to '4:2:0' chroma subsampling (optional, default `'4:2:0'`)
+    -   `options.optimiseCoding` **[boolean][7]** optimise Huffman coding tables (optional, default `true`)
+    -   `options.optimizeCoding` **[boolean][7]** alternative spelling of optimiseCoding (optional, default `true`)
+    -   `options.mozjpeg` **[boolean][7]** use mozjpeg defaults, equivalent to `{ trellisQuantisation: true, overshootDeringing: true, optimiseScans: true, quantisationTable: 3 }` (optional, default `false`)
+    -   `options.trellisQuantisation` **[boolean][7]** apply trellis quantisation (optional, default `false`)
+    -   `options.overshootDeringing` **[boolean][7]** apply overshoot deringing (optional, default `false`)
+    -   `options.optimiseScans` **[boolean][7]** optimise progressive scans, forces progressive (optional, default `false`)
+    -   `options.optimizeScans` **[boolean][7]** alternative spelling of optimiseScans (optional, default `false`)
+    -   `options.quantisationTable` **[number][9]** quantization table to use, integer 0-8 (optional, default `0`)
+    -   `options.quantizationTable` **[number][9]** alternative spelling of quantisationTable (optional, default `0`)
+    -   `options.force` **[boolean][7]** force JPEG output, otherwise attempt to use input format (optional, default `true`)
+
+### Examples
+
+```javascript
+// Convert any input to very high quality JPEG output
+const data = await sharp(input)
+  .jpeg({
+    quality: 100,
+    chromaSubsampling: '4:4:4'
+  })
+  .toBuffer();
+```
+
+```javascript
+// Use mozjpeg to reduce output JPEG file size (slower)
+const data = await sharp(input)
+  .jpeg({ mozjpeg: true })
+  .toBuffer();
+```
+
+-   Throws **[Error][4]** Invalid options
+
+Returns **Sharp** 
+
+## png
+
+Use these PNG options for output image.
+
+By default, PNG output is full colour at 8 or 16 bits per pixel.
+Indexed PNG input at 1, 2 or 4 bits per pixel is converted to 8 bits per pixel.
+Set `palette` to `true` for slower, indexed PNG output.
+
+### Parameters
+
+-   `options` **[Object][6]?** 
+    -   `options.progressive` **[boolean][7]** use progressive (interlace) scan (optional, default `false`)
+    -   `options.compressionLevel` **[number][9]** zlib compression level, 0 (fastest, largest) to 9 (slowest, smallest) (optional, default `6`)
+    -   `options.adaptiveFiltering` **[boolean][7]** use adaptive row filtering (optional, default `false`)
+    -   `options.palette` **[boolean][7]** quantise to a palette-based image with alpha transparency support (optional, default `false`)
+    -   `options.quality` **[number][9]** use the lowest number of colours needed to achieve given quality, sets `palette` to `true` (optional, default `100`)
+    -   `options.colours` **[number][9]** maximum number of palette entries, sets `palette` to `true` (optional, default `256`)
+    -   `options.colors` **[number][9]** alternative spelling of `options.colours`, sets `palette` to `true` (optional, default `256`)
+    -   `options.dither` **[number][9]** level of Floyd-Steinberg error diffusion, sets `palette` to `true` (optional, default `1.0`)
+    -   `options.force` **[boolean][7]** force PNG output, otherwise attempt to use input format (optional, default `true`)
+
+### Examples
+
+```javascript
+// Convert any input to full colour PNG output
+const data = await sharp(input)
+  .png()
+  .toBuffer();
+```
+
+```javascript
+// Convert any input to indexed PNG output (slower)
+const data = await sharp(input)
+  .png({ palette: true })
+  .toBuffer();
+```
+
+-   Throws **[Error][4]** Invalid options
+
+Returns **Sharp** 
+
+## webp
+
+Use these WebP options for output image.
+
+### Parameters
+
+-   `options` **[Object][6]?** output options
+    -   `options.quality` **[number][9]** quality, integer 1-100 (optional, default `80`)
+    -   `options.alphaQuality` **[number][9]** quality of alpha layer, integer 0-100 (optional, default `100`)
+    -   `options.lossless` **[boolean][7]** use lossless compression mode (optional, default `false`)
+    -   `options.nearLossless` **[boolean][7]** use near_lossless compression mode (optional, default `false`)
+    -   `options.smartSubsample` **[boolean][7]** use high quality chroma subsampling (optional, default `false`)
+    -   `options.reductionEffort` **[number][9]** level of CPU effort to reduce file size, integer 0-6 (optional, default `4`)
+    -   `options.pageHeight` **[number][9]?** page height for animated output
+    -   `options.loop` **[number][9]** number of animation iterations, use 0 for infinite animation (optional, default `0`)
+    -   `options.delay` **[Array][10]&lt;[number][9]>?** list of delays between animation frames (in milliseconds)
+    -   `options.force` **[boolean][7]** force WebP output, otherwise attempt to use input format (optional, default `true`)
+
+### Examples
+
+```javascript
+// Convert any input to lossless WebP output
+const data = await sharp(input)
+  .webp({ lossless: true })
+  .toBuffer();
+```
+
+-   Throws **[Error][4]** Invalid options
+
+Returns **Sharp** 
+
+## gif
+
+Use these GIF options for output image.
+
+Requires libvips compiled with support for ImageMagick or GraphicsMagick.
+The prebuilt binaries do not include this - see
+[installing a custom libvips][11].
+
+### Parameters
+
+-   `options` **[Object][6]?** output options
+    -   `options.pageHeight` **[number][9]?** page height for animated output
+    -   `options.loop` **[number][9]** number of animation iterations, use 0 for infinite animation (optional, default `0`)
+    -   `options.delay` **[Array][10]&lt;[number][9]>?** list of delays between animation frames (in milliseconds)
+    -   `options.force` **[boolean][7]** force GIF output, otherwise attempt to use input format (optional, default `true`)
+
+
+-   Throws **[Error][4]** Invalid options
+
+Returns **Sharp** 
+
+## tiff
+
+Use these TIFF options for output image.
+
+### Parameters
+
+-   `options` **[Object][6]?** output options
+    -   `options.quality` **[number][9]** quality, integer 1-100 (optional, default `80`)
+    -   `options.force` **[boolean][7]** force TIFF output, otherwise attempt to use input format (optional, default `true`)
+    -   `options.compression` **[string][2]** compression options: lzw, deflate, jpeg, ccittfax4 (optional, default `'jpeg'`)
+    -   `options.predictor` **[string][2]** compression predictor options: none, horizontal, float (optional, default `'horizontal'`)
+    -   `options.pyramid` **[boolean][7]** write an image pyramid (optional, default `false`)
+    -   `options.tile` **[boolean][7]** write a tiled tiff (optional, default `false`)
+    -   `options.tileWidth` **[number][9]** horizontal tile size (optional, default `256`)
+    -   `options.tileHeight` **[number][9]** vertical tile size (optional, default `256`)
+    -   `options.xres` **[number][9]** horizontal resolution in pixels/mm (optional, default `1.0`)
+    -   `options.yres` **[number][9]** vertical resolution in pixels/mm (optional, default `1.0`)
+    -   `options.bitdepth` **[number][9]** reduce bitdepth to 1, 2 or 4 bit (optional, default `8`)
+
+### Examples
+
+```javascript
+// Convert SVG input to LZW-compressed, 1 bit per pixel TIFF output
+sharp('input.svg')
+  .tiff({
+    compression: 'lzw',
+    bitdepth: 1
+  })
+  .toFile('1-bpp-output.tiff')
+  .then(info => { ... });
+```
+
+-   Throws **[Error][4]** Invalid options
+
+Returns **Sharp** 
+
+## avif
+
+Use these AVIF options for output image.
+
+Whilst it is possible to create AVIF images smaller than 16x16 pixels,
+most web browsers do not display these properly.
+
+### Parameters
+
+-   `options` **[Object][6]?** output options
+    -   `options.quality` **[number][9]** quality, integer 1-100 (optional, default `50`)
+    -   `options.lossless` **[boolean][7]** use lossless compression (optional, default `false`)
+    -   `options.speed` **[number][9]** CPU effort vs file size, 0 (slowest/smallest) to 8 (fastest/largest) (optional, default `5`)
+    -   `options.chromaSubsampling` **[string][2]** set to '4:4:4' to prevent chroma subsampling otherwise defaults to '4:2:0' chroma subsampling, requires libvips v8.11.0 (optional, default `'4:2:0'`)
+
+
+-   Throws **[Error][4]** Invalid options
+
+Returns **Sharp** 
+
+**Meta**
+
+-   **since**: 0.27.0
+
+## heif
+
+Use these HEIF options for output image.
+
+Support for patent-encumbered HEIC images requires the use of a
+globally-installed libvips compiled with support for libheif, libde265 and x265.
+
+### Parameters
+
+-   `options` **[Object][6]?** output options
+    -   `options.quality` **[number][9]** quality, integer 1-100 (optional, default `50`)
+    -   `options.compression` **[string][2]** compression format: av1, hevc (optional, default `'av1'`)
+    -   `options.lossless` **[boolean][7]** use lossless compression (optional, default `false`)
+    -   `options.speed` **[number][9]** CPU effort vs file size, 0 (slowest/smallest) to 8 (fastest/largest) (optional, default `5`)
+    -   `options.chromaSubsampling` **[string][2]** set to '4:4:4' to prevent chroma subsampling otherwise defaults to '4:2:0' chroma subsampling, requires libvips v8.11.0 (optional, default `'4:2:0'`)
+
+
+-   Throws **[Error][4]** Invalid options
+
+Returns **Sharp** 
+
+**Meta**
+
+-   **since**: 0.23.0
+
+## raw
+
+Force output to be raw, uncompressed, 8-bit unsigned integer (unit8) pixel data.
+Pixel ordering is left-to-right, top-to-bottom, without padding.
+Channel ordering will be RGB or RGBA for non-greyscale colourspaces.
+
+### Examples
+
+```javascript
+// Extract raw RGB pixel data from JPEG input
+const { data, info } = await sharp('input.jpg')
+  .raw()
+  .toBuffer({ resolveWithObject: true });
+```
+
+```javascript
+// Extract alpha channel as raw pixel data from PNG input
+const data = await sharp('input.png')
+  .ensureAlpha()
+  .extractChannel(3)
+  .toColourspace('b-w')
+  .raw()
+  .toBuffer();
+```
+
+Returns **Sharp** 
+
+## tile
+
+Use tile-based deep zoom (image pyramid) output.
+Set the format and options for tile images via the `toFormat`, `jpeg`, `png` or `webp` functions.
+Use a `.zip` or `.szi` file extension with `toFile` to write to a compressed archive file format.
+
+Warning: multiple sharp instances concurrently producing tile output can expose a possible race condition in some versions of libgsf.
+
+### Parameters
+
+-   `options` **[Object][6]?** 
+    -   `options.size` **[number][9]** tile size in pixels, a value between 1 and 8192. (optional, default `256`)
+    -   `options.overlap` **[number][9]** tile overlap in pixels, a value between 0 and 8192. (optional, default `0`)
+    -   `options.angle` **[number][9]** tile angle of rotation, must be a multiple of 90. (optional, default `0`)
+    -   `options.background` **([string][2] \| [Object][6])** background colour, parsed by the [color][12] module, defaults to white without transparency. (optional, default `{r:255,g:255,b:255,alpha:1}`)
+    -   `options.depth` **[string][2]?** how deep to make the pyramid, possible values are `onepixel`, `onetile` or `one`, default based on layout.
+    -   `options.skipBlanks` **[number][9]** threshold to skip tile generation, a value 0 - 255 for 8-bit images or 0 - 65535 for 16-bit images (optional, default `-1`)
+    -   `options.container` **[string][2]** tile container, with value `fs` (filesystem) or `zip` (compressed file). (optional, default `'fs'`)
+    -   `options.layout` **[string][2]** filesystem layout, possible values are `dz`, `iiif`, `zoomify` or `google`. (optional, default `'dz'`)
+    -   `options.centre` **[boolean][7]** centre image in tile. (optional, default `false`)
+    -   `options.center` **[boolean][7]** alternative spelling of centre. (optional, default `false`)
+    -   `options.id` **[string][2]** when `layout` is `iiif`, sets the `@id` attribute of `info.json` (optional, default `'https://example.com/iiif'`)
+
+### Examples
+
+```javascript
+sharp('input.tiff')
+  .png()
+  .tile({
+    size: 512
+  })
+  .toFile('output.dz', function(err, info) {
+    // output.dzi is the Deep Zoom XML definition
+    // output_files contains 512x512 tiles grouped by zoom level
+  });
+```
+
+-   Throws **[Error][4]** Invalid parameters
+
+Returns **Sharp** 
+
+[1]: #withmetadata
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise
+
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[8]: https://nodejs.org/api/buffer.html
+
+[9]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[10]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array
+
+[11]: https://sharp.pixelplumbing.com/install#custom-libvips
+
+[12]: https://www.npmjs.org/package/color

docs/api-resize.md

@@ -0,0 +1,258 @@
+<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
+
+## resize
+
+Resize image to `width`, `height` or `width x height`.
+
+When both a `width` and `height` are provided, the possible methods by which the image should **fit** these are:
+
+-   `cover`: (default) Preserving aspect ratio, ensure the image covers both provided dimensions by cropping/clipping to fit.
+-   `contain`: Preserving aspect ratio, contain within both provided dimensions using "letterboxing" where necessary.
+-   `fill`: Ignore the aspect ratio of the input and stretch to both provided dimensions.
+-   `inside`: Preserving aspect ratio, resize the image to be as large as possible while ensuring its dimensions are less than or equal to both those specified.
+-   `outside`: Preserving aspect ratio, resize the image to be as small as possible while ensuring its dimensions are greater than or equal to both those specified.
+
+Some of these values are based on the [object-fit][1] CSS property.
+
+When using a `fit` of `cover` or `contain`, the default **position** is `centre`. Other options are:
+
+-   `sharp.position`: `top`, `right top`, `right`, `right bottom`, `bottom`, `left bottom`, `left`, `left top`.
+-   `sharp.gravity`: `north`, `northeast`, `east`, `southeast`, `south`, `southwest`, `west`, `northwest`, `center` or `centre`.
+-   `sharp.strategy`: `cover` only, dynamically crop using either the `entropy` or `attention` strategy.
+
+Some of these values are based on the [object-position][2] CSS property.
+
+The experimental strategy-based approach resizes so one dimension is at its target length
+then repeatedly ranks edge regions, discarding the edge with the lowest score based on the selected strategy.
+
+-   `entropy`: focus on the region with the highest [Shannon entropy][3].
+-   `attention`: focus on the region with the highest luminance frequency, colour saturation and presence of skin tones.
+
+Possible interpolation kernels are:
+
+-   `nearest`: Use [nearest neighbour interpolation][4].
+-   `cubic`: Use a [Catmull-Rom spline][5].
+-   `mitchell`: Use a [Mitchell-Netravali spline][6].
+-   `lanczos2`: Use a [Lanczos kernel][7] with `a=2`.
+-   `lanczos3`: Use a Lanczos kernel with `a=3` (the default).
+
+### Parameters
+
+-   `width` **[number][8]?** pixels wide the resultant image should be. Use `null` or `undefined` to auto-scale the width to match the height.
+-   `height` **[number][8]?** pixels high the resultant image should be. Use `null` or `undefined` to auto-scale the height to match the width.
+-   `options` **[Object][9]?** 
+    -   `options.width` **[String][10]?** alternative means of specifying `width`. If both are present this take priority.
+    -   `options.height` **[String][10]?** alternative means of specifying `height`. If both are present this take priority.
+    -   `options.fit` **[String][10]** how the image should be resized to fit both provided dimensions, one of `cover`, `contain`, `fill`, `inside` or `outside`. (optional, default `'cover'`)
+    -   `options.position` **[String][10]** position, gravity or strategy to use when `fit` is `cover` or `contain`. (optional, default `'centre'`)
+    -   `options.background` **([String][10] \| [Object][9])** background colour when using a `fit` of `contain`, parsed by the [color][11] module, defaults to black without transparency. (optional, default `{r:0,g:0,b:0,alpha:1}`)
+    -   `options.kernel` **[String][10]** the kernel to use for image reduction. (optional, default `'lanczos3'`)
+    -   `options.withoutEnlargement` **[Boolean][12]** do not enlarge if the width _or_ height are already less than the specified dimensions, equivalent to GraphicsMagick's `>` geometry option. (optional, default `false`)
+    -   `options.fastShrinkOnLoad` **[Boolean][12]** take greater advantage of the JPEG and WebP shrink-on-load feature, which can lead to a slight moiré pattern on some images. (optional, default `true`)
+
+### Examples
+
+```javascript
+sharp(input)
+  .resize({ width: 100 })
+  .toBuffer()
+  .then(data => {
+    // 100 pixels wide, auto-scaled height
+  });
+```
+
+```javascript
+sharp(input)
+  .resize({ height: 100 })
+  .toBuffer()
+  .then(data => {
+    // 100 pixels high, auto-scaled width
+  });
+```
+
+```javascript
+sharp(input)
+  .resize(200, 300, {
+    kernel: sharp.kernel.nearest,
+    fit: 'contain',
+    position: 'right top',
+    background: { r: 255, g: 255, b: 255, alpha: 0.5 }
+  })
+  .toFile('output.png')
+  .then(() => {
+    // output.png is a 200 pixels wide and 300 pixels high image
+    // containing a nearest-neighbour scaled version
+    // contained within the north-east corner of a semi-transparent white canvas
+  });
+```
+
+```javascript
+const transformer = sharp()
+  .resize({
+    width: 200,
+    height: 200,
+    fit: sharp.fit.cover,
+    position: sharp.strategy.entropy
+  });
+// Read image data from readableStream
+// Write 200px square auto-cropped image data to writableStream
+readableStream
+  .pipe(transformer)
+  .pipe(writableStream);
+```
+
+```javascript
+sharp(input)
+  .resize(200, 200, {
+    fit: sharp.fit.inside,
+    withoutEnlargement: true
+  })
+  .toFormat('jpeg')
+  .toBuffer()
+  .then(function(outputBuffer) {
+    // outputBuffer contains JPEG image data
+    // no wider and no higher than 200 pixels
+    // and no larger than the input image
+  });
+```
+
+```javascript
+const scaleByHalf = await sharp(input)
+  .metadata()
+  .then(({ width }) => sharp(input)
+    .resize(Math.round(width * 0.5))
+    .toBuffer()
+  );
+```
+
+-   Throws **[Error][13]** Invalid parameters
+
+Returns **Sharp** 
+
+## extend
+
+Extends/pads the edges of the image with the provided background colour.
+This operation will always occur after resizing and extraction, if any.
+
+### Parameters
+
+-   `extend` **([number][8] \| [Object][9])** single pixel count to add to all edges or an Object with per-edge counts
+    -   `extend.top` **[number][8]**  (optional, default `0`)
+    -   `extend.left` **[number][8]**  (optional, default `0`)
+    -   `extend.bottom` **[number][8]**  (optional, default `0`)
+    -   `extend.right` **[number][8]**  (optional, default `0`)
+    -   `extend.background` **([String][10] \| [Object][9])** background colour, parsed by the [color][11] module, defaults to black without transparency. (optional, default `{r:0,g:0,b:0,alpha:1}`)
+
+### Examples
+
+```javascript
+// Resize to 140 pixels wide, then add 10 transparent pixels
+// to the top, left and right edges and 20 to the bottom edge
+sharp(input)
+  .resize(140)
+  .extend({
+    top: 10,
+    bottom: 20,
+    left: 10,
+    right: 10,
+    background: { r: 0, g: 0, b: 0, alpha: 0 }
+  })
+  ...
+```
+
+```javascript
+// Add a row of 10 red pixels to the bottom
+sharp(input)
+  .extend({
+    bottom: 10,
+    background: 'red'
+  })
+  ...
+```
+
+-   Throws **[Error][13]** Invalid parameters
+
+Returns **Sharp** 
+
+## extract
+
+Extract/crop a region of the image.
+
+-   Use `extract` before `resize` for pre-resize extraction.
+-   Use `extract` after `resize` for post-resize extraction.
+-   Use `extract` before and after for both.
+
+### Parameters
+
+-   `options` **[Object][9]** describes the region to extract using integral pixel values
+    -   `options.left` **[number][8]** zero-indexed offset from left edge
+    -   `options.top` **[number][8]** zero-indexed offset from top edge
+    -   `options.width` **[number][8]** width of region to extract
+    -   `options.height` **[number][8]** height of region to extract
+
+### Examples
+
+```javascript
+sharp(input)
+  .extract({ left: left, top: top, width: width, height: height })
+  .toFile(output, function(err) {
+    // Extract a region of the input image, saving in the same format.
+  });
+```
+
+```javascript
+sharp(input)
+  .extract({ left: leftOffsetPre, top: topOffsetPre, width: widthPre, height: heightPre })
+  .resize(width, height)
+  .extract({ left: leftOffsetPost, top: topOffsetPost, width: widthPost, height: heightPost })
+  .toFile(output, function(err) {
+    // Extract a region, resize, then extract from the resized image
+  });
+```
+
+-   Throws **[Error][13]** Invalid parameters
+
+Returns **Sharp** 
+
+## trim
+
+Trim "boring" pixels from all edges that contain values similar to the top-left pixel.
+Images consisting entirely of a single colour will calculate "boring" using the alpha channel, if any.
+
+The `info` response Object, obtained from callback of `.toFile()` or `.toBuffer()`,
+will contain `trimOffsetLeft` and `trimOffsetTop` properties.
+
+### Parameters
+
+-   `threshold` **[number][8]** the allowed difference from the top-left pixel, a number greater than zero. (optional, default `10`)
+
+
+-   Throws **[Error][13]** Invalid parameters
+
+Returns **Sharp** 
+
+[1]: https://developer.mozilla.org/en-US/docs/Web/CSS/object-fit
+
+[2]: https://developer.mozilla.org/en-US/docs/Web/CSS/object-position
+
+[3]: https://en.wikipedia.org/wiki/Entropy_%28information_theory%29
+
+[4]: http://en.wikipedia.org/wiki/Nearest-neighbor_interpolation
+
+[5]: https://en.wikipedia.org/wiki/Centripetal_Catmull%E2%80%93Rom_spline
+
+[6]: https://www.cs.utexas.edu/~fussell/courses/cs384g-fall2013/lectures/mitchell/Mitchell.pdf
+
+[7]: https://en.wikipedia.org/wiki/Lanczos_resampling#Lanczos_kernel
+
+[8]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[9]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[10]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[11]: https://www.npmjs.org/package/color
+
+[12]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[13]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error

docs/api-utility.md

@@ -0,0 +1,189 @@
+<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
+
+## format
+
+An Object containing nested boolean values representing the available input and output formats/methods.
+
+### Examples
+
+```javascript
+console.log(sharp.format);
+```
+
+Returns **[Object][1]** 
+
+## interpolators
+
+An Object containing the available interpolators and their proper values
+
+Type: [string][2]
+
+### nearest
+
+[Nearest neighbour interpolation][3]. Suitable for image enlargement only.
+
+### bilinear
+
+[Bilinear interpolation][4]. Faster than bicubic but with less smooth results.
+
+### bicubic
+
+[Bicubic interpolation][5] (the default).
+
+### locallyBoundedBicubic
+
+[LBB interpolation][6]. Prevents some "[acutance][7]" but typically reduces performance by a factor of 2.
+
+### nohalo
+
+[Nohalo interpolation][8]. Prevents acutance but typically reduces performance by a factor of 3.
+
+### vertexSplitQuadraticBasisSpline
+
+[VSQBS interpolation][9]. Prevents "staircasing" when enlarging.
+
+## versions
+
+An Object containing the version numbers of libvips and its dependencies.
+
+### Examples
+
+```javascript
+console.log(sharp.versions);
+```
+
+## cache
+
+Gets or, when options are provided, sets the limits of _libvips'_ operation cache.
+Existing entries in the cache will be trimmed after any change in limits.
+This method always returns cache statistics,
+useful for determining how much working memory is required for a particular task.
+
+### Parameters
+
+-   `options` **([Object][1] \| [boolean][10])** Object with the following attributes, or boolean where true uses default cache settings and false removes all caching (optional, default `true`)
+    -   `options.memory` **[number][11]** is the maximum memory in MB to use for this cache (optional, default `50`)
+    -   `options.files` **[number][11]** is the maximum number of files to hold open (optional, default `20`)
+    -   `options.items` **[number][11]** is the maximum number of operations to cache (optional, default `100`)
+
+### Examples
+
+```javascript
+const stats = sharp.cache();
+```
+
+```javascript
+sharp.cache( { items: 200 } );
+sharp.cache( { files: 0 } );
+sharp.cache(false);
+```
+
+Returns **[Object][1]** 
+
+## concurrency
+
+Gets or, when a concurrency is provided, sets
+the number of threads _libvips'_ should create to process each image.
+
+The default value is the number of CPU cores,
+except when using glibc-based Linux without jemalloc,
+where the default is `1` to help reduce memory fragmentation.
+
+A value of `0` will reset this to the number of CPU cores.
+
+The maximum number of images that can be processed in parallel
+is limited by libuv's `UV_THREADPOOL_SIZE` environment variable.
+
+This method always returns the current concurrency.
+
+### Parameters
+
+-   `concurrency` **[number][11]?** 
+
+### Examples
+
+```javascript
+const threads = sharp.concurrency(); // 4
+sharp.concurrency(2); // 2
+sharp.concurrency(0); // 4
+```
+
+Returns **[number][11]** concurrency
+
+## queue
+
+An EventEmitter that emits a `change` event when a task is either:
+
+-   queued, waiting for _libuv_ to provide a worker thread
+-   complete
+
+### Examples
+
+```javascript
+sharp.queue.on('change', function(queueLength) {
+  console.log('Queue contains ' + queueLength + ' task(s)');
+});
+```
+
+## counters
+
+Provides access to internal task counters.
+
+-   queue is the number of tasks this module has queued waiting for _libuv_ to provide a worker thread from its pool.
+-   process is the number of resize tasks currently being processed.
+
+### Examples
+
+```javascript
+const counters = sharp.counters(); // { queue: 2, process: 4 }
+```
+
+Returns **[Object][1]** 
+
+## simd
+
+Get and set use of SIMD vector unit instructions.
+Requires libvips to have been compiled with liborc support.
+
+Improves the performance of `resize`, `blur` and `sharpen` operations
+by taking advantage of the SIMD vector unit of the CPU, e.g. Intel SSE and ARM NEON.
+
+### Parameters
+
+-   `simd` **[boolean][10]**  (optional, default `true`)
+
+### Examples
+
+```javascript
+const simd = sharp.simd();
+// simd is `true` if the runtime use of liborc is currently enabled
+```
+
+```javascript
+const simd = sharp.simd(false);
+// prevent libvips from using liborc at runtime
+```
+
+Returns **[boolean][10]** 
+
+[1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[3]: http://en.wikipedia.org/wiki/Nearest-neighbor_interpolation
+
+[4]: http://en.wikipedia.org/wiki/Bilinear_interpolation
+
+[5]: http://en.wikipedia.org/wiki/Bicubic_interpolation
+
+[6]: https://github.com/jcupitt/libvips/blob/master/libvips/resample/lbb.cpp#L100
+
+[7]: http://en.wikipedia.org/wiki/Acutance
+
+[8]: http://eprints.soton.ac.uk/268086/
+
+[9]: https://github.com/jcupitt/libvips/blob/master/libvips/resample/vsqbs.cpp#L48
+
+[10]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[11]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number

docs/build.js

@@ -0,0 +1,25 @@
+'use strict';
+
+const fs = require('fs').promises;
+const path = require('path');
+const documentation = require('documentation');
+
+[
+  'constructor',
+  'input',
+  'resize',
+  'composite',
+  'operation',
+  'colour',
+  'channel',
+  'output',
+  'utility'
+].forEach(async (m) => {
+  const input = path.join('lib', `${m}.js`);
+  const output = path.join('docs', `api-${m}.md`);
+
+  const ast = await documentation.build(input, { shallow: true });
+  const markdown = await documentation.formats.md(ast, { markdownToc: false });
+
+  await fs.writeFile(output, markdown);
+});

docs/firebase.json

@@ -0,0 +1,118 @@
+{
+  "hosting": {
+    "site": "pixelplumbing-sharp",
+    "public": ".",
+    "ignore": [
+      ".*",
+      "build.js",
+      "firebase.json",
+      "*.md",
+      "image/**",
+      "search-index/**"
+    ],
+    "headers": [
+      {
+        "source": "**",
+        "headers": [
+          {
+            "key": "Cache-Control",
+            "value": "max-age=86400"
+          }
+        ]
+      }
+    ],
+    "redirects": [
+      {
+        "source": "**/install/**",
+        "destination": "/install",
+        "type": 301
+      },
+      {
+        "source": "/page/install",
+        "destination": "/install",
+        "type": 301
+      },
+      {
+        "source": "**/api-constructor/**",
+        "destination": "/api-constructor",
+        "type": 301
+      },
+      {
+        "source": "**/api-input/**",
+        "destination": "/api-input",
+        "type": 301
+      },
+      {
+        "source": "**/api-output/**",
+        "destination": "/api-output",
+        "type": 301
+      },
+      {
+        "source": "**/api-resize/**",
+        "destination": "/api-resize",
+        "type": 301
+      },
+      {
+        "source": "**/api-compsite/**",
+        "destination": "/api-compsite",
+        "type": 301
+      },
+      {
+        "source": "**/api-operation/**",
+        "destination": "/api-operation",
+        "type": 301
+      },
+      {
+        "source": "**/api-colour/**",
+        "destination": "/api-colour",
+        "type": 301
+      },
+      {
+        "source": "**/api-channel/**",
+        "destination": "/api-channel",
+        "type": 301
+      },
+      {
+        "source": "**/api-utility/**",
+        "destination": "/api-utility",
+        "type": 301
+      },
+      {
+        "source": "/page/api",
+        "destination": "/api-constructor",
+        "type": 301
+      },
+      {
+        "source": "**/performance/**",
+        "destination": "/performance",
+        "type": 301
+      },
+      {
+        "source": "/page/performance",
+        "destination": "/performance",
+        "type": 301
+      },
+      {
+        "source": "**/changelog/**",
+        "destination": "/changelog",
+        "type": 301
+      },
+      {
+        "source": "/page/changelog",
+        "destination": "/changelog",
+        "type": 301
+      },
+      {
+        "source": "/en/**",
+        "destination": "/",
+        "type": 301
+      }
+    ],
+    "rewrites": [
+      {
+        "source": "**",
+        "destination": "/index.html"
+      }
+    ]
+  }
+}

docs/humans.txt

@@ -0,0 +1,211 @@
+/* THANKS */
+
+Name: John Cupitt
+GitHub: https://github.com/jcupitt
+
+Name: Pierre Inglebert
+GitHub: https://github.com/pierreinglebert
+
+Name: Jonathan Ong
+GitHub: https://github.com/jonathanong
+
+Name: Chanon Sajjamanochai
+GitHub: https://github.com/chanon
+
+Name: Juliano Julio
+GitHub: https://github.com/julianojulio
+
+Name: Daniel Gasienica
+GitHub: https://github.com/gasi
+
+Name: Julian Walker
+GitHub: https://github.com/julianwa
+
+Name: Amit Pitaru
+GitHub: https://github.com/apitaru
+
+Name: Brandon Aaron
+GitHub: https://github.com/brandonaaron
+
+Name: Andreas Lind
+GitHub: https://github.com/papandreouGitHub:
+
+Name: Maurus Cuelenaere
+GitHub: https://github.com/mcuelenaere
+
+Name: Linus Unnebäck
+GitHub: https://github.com/LinusU
+
+Name: Victor Mateevitsi
+GitHub: https://github.com/mvictoras
+
+Name: Alaric Holloway
+GitHub: https://github.com/skedastik
+
+Name: Bernhard K. Weisshuhn
+GitHub: https://github.com/bkw
+
+Name: David A. Carley
+GitHub: https://github.com/dacarley
+
+Name: John Tobin
+GitHub: https://github.com/jtobinisaniceguy
+
+Name: Kenton Gray
+GitHub: https://github.com/kentongray
+
+Name: Felix Bünemann
+GitHub: https://github.com/felixbuenemann
+
+Name: Samy Al Zahrani
+GitHub: https://github.com/salzhrani
+
+Name: Chintan Thakkar
+GitHub: https://github.com/lemnisk8
+
+Name: F. Orlando Galashan
+GitHub: https://github.com/frulo
+
+Name: Kleis Auke Wolthuizen
+GitHub: https://github.com/kleisauke
+
+Name: Matt Hirsch
+GitHub: https://github.com/mhirsch
+
+Name: Rahul Nanwani
+GitHub: https://github.com/rnanwani
+
+Name: Matthias Thoemmes
+GitHub: https://github.com/cmtt
+
+Name: Patrick Paskaris
+GitHub: https://github.com/ppaskaris
+
+Name: Jérémy Lal
+GitHub: https://github.com/kapouer
+
+Name: Alice Monday
+GitHub: https://github.com/alice0meta
+
+Name: Kristo Jorgenson
+GitHub: https://github.com/kristojorg
+
+Name: Yves Bos
+GitHub: https://github.com/YvesBos
+
+Name: Nicolas Coden
+GitHub: https://github.com/ncoden
+
+Name: Matt Parrish
+GitHub: https://github.com/pbomb
+
+Name: Matthew McEachen
+GitHub: https://github.com/mceachen
+
+Name: Jarda Kotěšovec
+GitHub: https://github.com/jardakotesovec
+
+Name: Kenric D'Souza
+GitHub: https://github.com/AzureByte
+
+Name: Oleh Aleinyk
+GitHub: https://github.com/oaleynik
+
+Name: Marcel Bretschneider
+GitHub: https://github.com/3epnm
+
+Name: Andrea Bianco
+GitHub: https://github.com/BiancoA
+
+Name: Rik Heywood
+GitHub: https://github.com/rikh42
+
+Name: Thomas Parisot
+GitHub: https://github.com/oncletom
+
+Name: Nathan Graves
+GitHub: https://github.com/woolite64
+
+Name: Tom Lokhorst
+GitHub: https://github.com/tomlokhorst
+
+Name: Espen Hovlandsdal
+GitHub: https://github.com/rexxars
+
+Name: Sylvain Dumont
+GitHub: https://github.com/sylvaindumont
+
+Name: Alun Davies
+GitHub: https://github.com/alundavies
+
+Name: Aidan Hoolachan
+GitHub: https://github.com/ajhool
+
+Name: Axel Eirola
+GitHub: https://github.com/aeirola
+
+Name: Freezy
+GitHub: https://github.com/freezy
+
+Name: Julian Aubourg
+GitHub: https://github.com/jaubourg
+
+Name: Keith Belovay
+GitHub: https://github.com/fromkeith
+
+Name: Michael B. Klein
+GitHub: https://github.com/mbklein
+
+Name: Jakub Michálek
+GitHub: https://github.com/Goues
+
+Name: Ilya Ovdin
+GitHub: https://github.com/iovdin
+
+Name: Andargor
+GitHub: https://github.com/Andargor
+
+Name: Nicolas Stepien
+GitHub: https://github.com/MayhemYDG
+
+Name: Paul Neave
+GitHub: https://github.com/neave
+
+Name: Brendan Kennedy
+GitHub: https://github.com/rustyguts
+
+Name: Brychan Bennett-Odlum
+GitHub: https://github.com/BrychanOdlum
+
+Name: Edward Silverton
+GitHub: https://github.com/edsilv
+
+Name: Dumitru Deveatii
+GitHub: https://github.com/dimadeveatii
+
+Name: Roland Asmann
+GitHub: https://github.com/malice00
+
+Name: Roman Malieiev
+GitHub: https://github.com/romaleev
+
+Name: Jerome Vouillon
+GitHub: https://github.com/vouillon
+
+Name: Tomáš Szabo
+GitHub: https://github.com/deftomat
+
+Name: Robert O'Rourke
+GitHub: https://github.com/roborourke
+
+Name: Denis Soldatov
+GitHub: https://github.com/derom
+
+Name: Stefan Probst
+GitHub: https://github.com/stefanprobst
+
+Name: Thomas Beiganz
+GitHub: https://github.com/beig
+
+Name: Florian Busch
+GitHub: https://github.com/florian-busch

docs/image/sharp-logo-mono.svg

@@ -0,0 +1,11 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="86 86 550 550">
+<!-- Creative Commons CC0 1.0 Universal Public Domain Dedication -->
+  <defs>
+    <mask id="c">
+      <path fill="none" stroke="#fff" stroke-width="80" d="M258.411 285.777l200.176-26.8M244.113 466.413L451.44 438.66m.001 0V238.484m0-150.121v171.572l178.725-23.917m-359.843 19.584V477.22m2.387 156.95V462.591L93.984 486.515"/>
+      <path fill="none" stroke="#000" stroke-width="112" d="M451.441 610.246V438.66l178.725-23.91M269.688 112.59v171.58L90.964 308.093"/>
+    </mask>
+  </defs>
+  <path mask="url(#c)" fill="none" stroke="#000" stroke-width="80" d="M258.411 285.777l200.176-26.8M244.113 466.413L451.44 438.66m.001 0V238.484m0-150.121v171.572l178.725-23.917m-359.843 19.584V477.22m2.387 156.95V462.591L93.984 486.515"/>
+  <path fill="none" stroke="#000" stroke-width="80" d="M451.441 610.246V438.66l178.725-23.91M269.688 112.59v171.58L90.964 308.093"/>
+</svg>

docs/image/sharp-logo.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="86 86 550 550">
+<!-- Creative Commons CC0 1.0 Universal Public Domain Dedication -->
+<path fill="none" stroke="#9c0" stroke-width="80" d="M258.411 285.777l200.176-26.8M244.113 466.413L451.44 438.66M451.441 438.66V238.484M451.441 88.363v171.572l178.725-23.917M270.323 255.602V477.22M272.71 634.17V462.591L93.984 486.515"/>
+<path fill="none" stroke="#090" stroke-width="80" d="M451.441 610.246V438.66l178.725-23.91M269.688 112.59v171.58L90.964 308.093"/>
+</svg>

docs/install.md

@@ -0,0 +1,242 @@
+# Installation
+
+```sh
+npm install sharp
+```
+
+```sh
+yarn add sharp
+```
+
+## Prerequisites
+
+* Node.js v10+
+
+## Prebuilt binaries
+
+Ready-compiled sharp and libvips binaries are provided for use with
+Node.js v10+ on the most common platforms:
+
+* macOS x64 (>= 10.13)
+* Linux x64 (glibc >= 2.17, musl >= 1.1.24)
+* Linux ARM64 (glibc >= 2.29, musl >= 1.1.24)
+* Windows x64
+* Windows x86
+
+An ~7.5MB tarball containing libvips and its most commonly used dependencies
+is downloaded via HTTPS and stored within `node_modules/sharp/vendor` during `npm install`.
+
+This provides support for the
+JPEG, PNG, WebP, AVIF, TIFF, GIF (input) and SVG (input) image formats.
+
+The following platforms have prebuilt libvips but not sharp:
+
+* macOS ARM64
+* Linux ARMv6
+* Linux ARMv7 (glibc >= 2.28)
+* Windows ARM64
+
+The following platforms require compilation of both libvips and sharp from source:
+
+* Linux x86
+* Linux x64 (glibc <= 2.16, includes RHEL/CentOS 6)
+* Linux ARM64 (glibc <= 2.28)
+* Linux PowerPC
+* FreeBSD
+* OpenBSD
+
+## Common problems
+
+The architecture and platform of Node.js used for `npm install`
+must be the same as the architecture and platform of Node.js used at runtime.
+
+When using npm v6 or earlier, the `npm install --unsafe-perm` flag must be used when installing as `root` or a `sudo` user.
+
+When using npm v7, the user running `npm install` must own the directory it is run in.
+
+The `npm install --ignore-scripts=false` flag must be used when `npm` has been configured to ignore installation scripts.
+
+Check the output of running `npm install --verbose sharp` for useful error messages.
+
+## Apple M1
+
+Prebuilt libvips binaries are provided for macOS on ARM64 (since sharp v0.28.0).
+
+During `npm install` sharp will be built locally,
+which requires Xcode and Python - see
+[building from source](#building-from-source).
+
+When this new ARM64 CPU is made freely available
+to open source projects via a CI service
+then prebuilt sharp binaries can also be provided.
+
+## Custom libvips
+
+To use a custom, globally-installed version of libvips instead of the provided binaries,
+make sure it is at least the version listed under `config.libvips` in the `package.json` file
+and that it can be located using `pkg-config --modversion vips-cpp`.
+
+For help compiling libvips from source, please see
+[https://libvips.github.io/libvips/install.html#building-libvips-from-a-source-tarball](https://libvips.github.io/libvips/install.html#building-libvips-from-a-source-tarball).
+
+The use of a globally-installed libvips is unsupported on Windows.
+
+## Building from source
+
+This module will be compiled from source at `npm install` time when:
+
+* a globally-installed libvips is detected (set the `SHARP_IGNORE_GLOBAL_LIBVIPS` environment variable to skip this),
+* prebuilt sharp binaries do not exist for the current platform, or
+* when the `npm install --build-from-source` flag is used.
+
+Building from source requires:
+
+* C++11 compiler
+* [node-gyp](https://github.com/nodejs/node-gyp#installation) and its dependencies
+
+## Custom prebuilt binaries
+
+This is an advanced approach that most people will not require.
+
+To install the prebuilt sharp binaries from a custom URL,
+set the `sharp_binary_host` npm config option
+or the `npm_config_sharp_binary_host` environment variable.
+
+To install the prebuilt libvips binaries from a custom URL,
+set the `sharp_libvips_binary_host` npm config option
+or the `npm_config_sharp_libvips_binary_host` environment variable.
+
+The version subpath and file name are appended to these. There should be tarballs available
+that are compressed with both gzip and Brotli, as the format downloaded will vary depending
+on whether the user's version of Node supports Brotli decompression (Node.js v10.16.0+)
+
+For example, if `sharp_libvips_binary_host` is set to `https://hostname/path`
+and the libvips version is `1.2.3` then the resultant URL will be
+`https://hostname/path/v1.2.3/libvips-1.2.3-platform-arch.tar.br` or 
+`https://hostname/path/v1.2.3/libvips-1.2.3-platform-arch.tar.gz`.
+
+See the Chinese mirror below for a further example.
+
+## Chinese mirror
+
+Alibaba provide a mirror site based in China containing binaries for both sharp and libvips.
+
+To use this either set the following configuration:
+
+```sh
+npm config set sharp_binary_host "https://npm.taobao.org/mirrors/sharp"
+npm config set sharp_libvips_binary_host "https://npm.taobao.org/mirrors/sharp-libvips"
+npm install sharp
+```
+
+or set the following environment variables:
+
+```sh
+npm_config_sharp_binary_host="https://npm.taobao.org/mirrors/sharp" \
+  npm_config_sharp_libvips_binary_host="https://npm.taobao.org/mirrors/sharp-libvips" \
+  npm install sharp
+```
+
+## FreeBSD
+
+The `vips` package must be installed before `npm install` is run.
+
+```sh
+pkg install -y pkgconf vips
+```
+
+```sh
+cd /usr/ports/graphics/vips/ && make install clean
+```
+
+## Linux memory allocator
+
+The default memory allocator on most glibc-based Linux systems
+(e.g. Debian, Red Hat) is unsuitable for long-running, multi-threaded
+processes that involve lots of small memory allocations.
+
+For this reason, by default, sharp will limit the use of thread-based
+[concurrency](api-utility#concurrency) when the glibc allocator is
+detected at runtime.
+
+To help avoid fragmentation and improve performance on these systems,
+the use of an alternative memory allocator such as
+[jemalloc](https://github.com/jemalloc/jemalloc) is recommended.
+
+Those using musl-based Linux (e.g. Alpine) and non-Linux systems are
+unaffected.
+
+## Heroku
+
+Add the
+[jemalloc buildpack](https://github.com/gaffneyc/heroku-buildpack-jemalloc)
+to reduce the effects of memory fragmentation.
+
+Set
+[NODE_MODULES_CACHE](https://devcenter.heroku.com/articles/nodejs-support#cache-behavior)
+to `false` when using the `yarn` package manager.
+
+## AWS Lambda
+
+Set the Lambda runtime to `nodejs12.x`.
+
+The binaries in the `node_modules` directory of the
+[deployment package](https://docs.aws.amazon.com/lambda/latest/dg/nodejs-package.html)
+must be for the Linux x64 platform.
+
+When building your deployment package on machines other than Linux x64 (glibc),
+run the following commands:
+
+macOS:
+```sh
+rm -rf node_modules/sharp
+SHARP_IGNORE_GLOBAL_LIBVIPS=1 npm install --arch=x64 --platform=linux sharp
+```
+
+Windows:
+```sh
+rmdir /s /q node_modules/sharp
+npm install --arch=x64 --platform=linux sharp
+```
+
+Alternatively a Docker container closely matching the Lambda runtime can be used:
+
+```sh
+rm -rf node_modules/sharp
+docker run -v "$PWD":/var/task lambci/lambda:build-nodejs12.x npm install sharp
+```
+
+To get the best performance select the largest memory available.
+A 1536 MB function provides ~12x more CPU time than a 128 MB function.
+
+## Webpack
+
+Ensure sharp is added to the
+[externals](https://webpack.js.org/configuration/externals/)
+configuration.
+
+```js
+externals: {
+  'sharp': 'commonjs sharp'
+}
+```
+
+## Worker threads
+
+The main thread must call `require('sharp')`
+before worker threads are created
+to ensure shared libraries remain loaded in memory
+until after all threads are complete.
+
+## Known conflicts
+
+### Canvas and Windows
+
+The prebuilt binaries provided by `canvas` for Windows depend on the unmaintained GTK 2, last updated in 2011.
+
+These conflict with the modern, up-to-date binaries provided by sharp.
+
+If both modules are used in the same Windows process, the following error will occur:
+```
+The specified procedure could not be found.
+```

docs/performance.md

@@ -0,0 +1,68 @@
+# Performance
+
+A test to benchmark the performance of this module relative to alternatives.
+
+## The contenders
+
+* [jimp](https://www.npmjs.com/package/jimp) v0.16.1 - Image processing in pure JavaScript. Provides bicubic interpolation.
+* [mapnik](https://www.npmjs.org/package/mapnik) v4.5.6 - Whilst primarily a map renderer, Mapnik contains bitmap image utilities.
+* [imagemagick](https://www.npmjs.com/package/imagemagick) v0.1.3 - Supports filesystem only and "*has been unmaintained for a long time*".
+* [gm](https://www.npmjs.com/package/gm) v1.23.1 - Fully featured wrapper around GraphicsMagick's `gm` command line utility.
+* sharp v0.28.0 / libvips v8.10.6 - Caching within libvips disabled to ensure a fair comparison.
+
+## The task
+
+Decompress a 2725x2225 JPEG image,
+resize to 720x588 using Lanczos 3 resampling (where available),
+then compress to JPEG at a "quality" setting of 80.
+
+## Test environment
+
+* AWS EC2 eu-west-1 [c5ad.xlarge](https://aws.amazon.com/ec2/instance-types/c5/) (4x AMD EPYC 7R32)
+* Ubuntu 20.10 (ami-03f10415e8b0bfb86)
+* Node.js v14.16.0
+
+## Results
+
+| Module             | Input  | Output | Ops/sec | Speed-up |
+| :----------------- | :----- | :----- | ------: | -------: |
+| jimp               | buffer | buffer |    0.78 |      1.0 |
+| mapnik             | buffer | buffer |    3.39 |      4.3 |
+| gm                 | buffer | buffer |    7.84 |     10.1 |
+| gm                 | file   | file   |    9.24 |     11.8 |
+| imagemagick        | file   | file   |    9.37 |     12.0 |
+| sharp              | stream | stream |   26.84 |     34.4 |
+| sharp              | file   | file   |   29.76 |     38.2 |
+| sharp              | buffer | buffer |   31.60 |     40.5 |
+
+Greater libvips performance can be expected with caching enabled (default)
+and using 8+ core machines, especially those with larger L1/L2 CPU caches.
+
+The I/O limits of the relevant (de)compression library will generally determine maximum throughput.
+
+## Running the benchmark test
+
+Requires _ImageMagick_, _GraphicsMagick_ and _Mapnik_:
+
+```sh
+brew install imagemagick
+brew install graphicsmagick
+brew install mapnik
+```
+
+```sh
+sudo apt-get install build-essential imagemagick libmagick++-dev graphicsmagick libmapnik-dev
+```
+
+```sh
+sudo yum install ImageMagick-devel ImageMagick-c++-devel GraphicsMagick mapnik-devel
+```
+
+```sh
+git clone https://github.com/lovell/sharp.git
+cd sharp
+npm install --build-from-source
+cd test/bench
+npm install
+npm test
+```

docs/robots.txt

@@ -0,0 +1,2 @@
+User-agent: *
+Disallow:

docs/search-index/build.js

@@ -0,0 +1,60 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const { extractDescription, extractKeywords } = require('./extract');
+
+const searchIndex = [];
+
+// Install
+const contents = fs.readFileSync(path.join(__dirname, '..', 'install.md'), 'utf8');
+const matches = contents.matchAll(
+  /## (?<title>[A-Za-z0-9 ]+)\n\n(?<body>[^#]+)/gs
+);
+for (const match of matches) {
+  const { title, body } = match.groups;
+  const description = extractDescription(body);
+
+  searchIndex.push({
+    t: title,
+    d: description,
+    k: extractKeywords(`${title} ${description}`),
+    l: `/install#${title.toLowerCase().replace(/ /g, '-')}`
+  });
+}
+
+// API
+[
+  'constructor',
+  'input',
+  'output',
+  'resize',
+  'composite',
+  'operation',
+  'channel',
+  'colour',
+  'utility'
+].forEach((section) => {
+  const contents = fs.readFileSync(path.join(__dirname, '..', `api-${section}.md`), 'utf8');
+  const matches = contents.matchAll(
+    /\n## (?<title>[A-Za-z]+)\n\n(?<firstparagraph>.+?)\n\n/gs
+  );
+  for (const match of matches) {
+    const { title, firstparagraph } = match.groups;
+    const description = firstparagraph.startsWith('###')
+      ? 'Constructor'
+      : extractDescription(firstparagraph);
+
+    searchIndex.push({
+      t: title,
+      d: description,
+      k: extractKeywords(`${title} ${description}`),
+      l: `/api-${section}#${title.toLowerCase()}`
+    });
+  }
+});
+
+fs.writeFileSync(
+  path.join(__dirname, '..', 'search-index.json'),
+  JSON.stringify(searchIndex)
+);

docs/search-index/extract.js

@@ -0,0 +1,24 @@
+'use strict';
+
+const stopWords = require('./stop-words');
+
+const extractDescription = (str) =>
+  str
+    .replace(/\(http[^)]+/g, '')
+    .replace(/\s+/g, ' ')
+    .replace(/[^A-Za-z0-9_/\-,. ]/g, '')
+    .replace(/\s+/g, ' ')
+    .substr(0, 180)
+    .trim();
+
+const extractKeywords = (str) =>
+  [
+    ...new Set(
+      str
+        .split(/[ -/]/)
+        .map((word) => word.toLowerCase().replace(/[^a-z]/g, ''))
+        .filter((word) => word.length > 2 && word.length < 15 && !stopWords.includes(word))
+    )
+  ].join(' ');
+
+module.exports = { extractDescription, extractKeywords };

docs/search-index/stop-words.js

@@ -0,0 +1,92 @@
+'use strict';
+
+module.exports = [
+  'about',
+  'after',
+  'all',
+  'allows',
+  'already',
+  'also',
+  'alternative',
+  'always',
+  'and',
+  'any',
+  'are',
+  'based',
+  'been',
+  'before',
+  'both',
+  'call',
+  'can',
+  'containing',
+  'default',
+  'does',
+  'each',
+  'either',
+  'ensure',
+  'etc',
+  'every',
+  'for',
+  'from',
+  'get',
+  'gets',
+  'given',
+  'has',
+  'have',
+  'how',
+  'image',
+  'involve',
+  'its',
+  'least',
+  'lots',
+  'may',
+  'more',
+  'most',
+  'much',
+  'must',
+  'non',
+  'not',
+  'occur',
+  'occurs',
+  'options',
+  'over',
+  'perform',
+  'performs',
+  'provide',
+  'provided',
+  'ready',
+  'same',
+  'see',
+  'set',
+  'sets',
+  'should',
+  'since',
+  'spelling',
+  'such',
+  'support',
+  'supported',
+  'sure',
+  'take',
+  'that',
+  'the',
+  'their',
+  'there',
+  'therefore',
+  'these',
+  'this',
+  'under',
+  'unless',
+  'until',
+  'use',
+  'used',
+  'using',
+  'value',
+  'values',
+  'when',
+  'which',
+  'while',
+  'will',
+  'with',
+  'without',
+  'you'
+];

index.js

@@ -1,241 +0,0 @@
-/*jslint node: true */
-'use strict';
-
-var Promise = require('bluebird');
-var sharp = require('./build/Release/sharp');
-
-var Sharp = function(input) {
-  if (!(this instanceof Sharp)) {
-    return new Sharp(input);
-  }
-  this.options = {
-    width: -1,
-    height: -1,
-    canvas: 'c',
-    angle: 0,
-    withoutEnlargement: false,
-    sharpen: false,
-    interpolator: 'bilinear',
-    progressive: false,
-    sequentialRead: false,
-    quality: 80,
-    compressionLevel: 6,
-    output: '__jpeg'
-  };
-  if (typeof input === 'string') {
-    this.options.fileIn = input;
-  } else if (typeof input ==='object' && input instanceof Buffer) {
-    if (input.length > 0) {
-      this.options.bufferIn = input;
-    } else {
-      throw new Error('Buffer is empty');
-    }
-  } else {
-    throw new Error('Unsupported input ' + typeof input);
-  }
-  return this;
-};
-module.exports = Sharp;
-
-Sharp.prototype.crop = function() {
-  this.options.canvas = 'c';
-  return this;
-};
-
-Sharp.prototype.embedWhite = function() {
-  this.options.canvas = 'w';
-  return this;
-};
-
-Sharp.prototype.embedBlack = function() {
-  this.options.canvas = 'b';
-  return this;
-};
-
-Sharp.prototype.max = function() {
-  this.options.canvas = 'm';
-  return this;
-};
-
-/*
-  Rotate output image by 0, 90, 180 or 270 degrees
-  Auto-rotation based on the EXIF Orientation tag is represented by an angle of -1
-*/
-Sharp.prototype.rotate = function(angle) {
-  if (typeof angle === 'undefined') {
-    this.options.angle = -1;
-  } else if (!Number.isNaN(angle) && [0, 90, 180, 270].indexOf(angle) !== -1) {
-    this.options.angle = angle;
-  } else {
-    throw new Error('Unsupported angle (0, 90, 180, 270) ' + angle);
-  }
-  return this;
-};
-
-/*
-  Do not enlarge the output if the input width *or* height are already less than the required dimensions
-  This is equivalent to GraphicsMagick's ">" geometry option:
-    "change the dimensions of the image only if its width or height exceeds the geometry specification"
-*/
-Sharp.prototype.withoutEnlargement = function(withoutEnlargement) {
-  this.options.withoutEnlargement = (typeof withoutEnlargement === 'boolean') ? withoutEnlargement : true;
-  return this;
-};
-
-Sharp.prototype.sharpen = function(sharpen) {
-  this.options.sharpen = (typeof sharpen === 'boolean') ? sharpen : true;
-  return this;
-};
-
-/*
-  Use bilinear interpolation for the affine transformation (fastest, default)
-*/
-Sharp.prototype.bilinearInterpolation = function() {
-  this.options.interpolator = 'bilinear';
-  return this;
-};
-
-/*
-  Use bicubic interpolation for the affine transformation
-*/
-Sharp.prototype.bicubicInterpolation = function() {
-  this.options.interpolator = 'bicubic';
-  return this;
-};
-
-/*
-  Use Nohalo interpolation for the affine transformation
-*/
-Sharp.prototype.nohaloInterpolation = function() {
-  this.options.interpolator = 'nohalo';
-  return this;
-};
-
-Sharp.prototype.progressive = function(progressive) {
-  this.options.progressive = (typeof progressive === 'boolean') ? progressive : true;
-  return this;
-};
-
-Sharp.prototype.sequentialRead = function(sequentialRead) {
-  this.options.sequentialRead = (typeof sequentialRead === 'boolean') ? sequentialRead : true;
-  return this;
-};
-
-Sharp.prototype.quality = function(quality) {
-  if (!Number.isNaN(quality) && quality >= 1 && quality <= 100) {
-    this.options.quality = quality;
-  } else {
-    throw new Error('Invalid quality (1 to 100) ' + quality);
-  }
-  return this;
-};
-
-Sharp.prototype.compressionLevel = function(compressionLevel) {
-  if (!Number.isNaN(compressionLevel) && compressionLevel >= -1 && compressionLevel <= 9) {
-    this.options.compressionLevel = compressionLevel;
-  } else {
-    throw new Error('Invalid compressionLevel (-1 to 9) ' + compressionLevel);
-  }
-  return this;
-};
-
-Sharp.prototype.resize = function(width, height) {
-  if (!width) {
-    this.options.width = -1;
-  } else {
-    if (!Number.isNaN(width)) {
-      this.options.width = width;
-    } else {
-      throw new Error('Invalid width ' + width);
-    }
-  }
-  if (!height) {
-    this.options.height = -1;
-  } else {
-    if (!Number.isNaN(height)) {
-      this.options.height = height;
-    } else {
-      throw new Error('Invalid height ' + height);
-    }
-  }
-  return this;
-};
-
-/*
-  Write output image data to a file
-*/
-Sharp.prototype.toFile = function(output, callback) {
-  if (!output || output.length === 0) {
-    var errOutputInvalid = new Error('Invalid output');
-    if (typeof callback === 'function') {
-      callback(errOutputInvalid);
-    } else {
-      return Promise.reject(errOutputInvalid);
-    }
-  } else {
-    if (this.options.fileIn === output) {
-      var errOutputIsInput = new Error('Cannot use same file for input and output');
-      if (typeof callback === 'function') {
-        callback(errOutputIsInput);
-      } else {
-        return Promise.reject(errOutputIsInput);
-      }
-    } else {
-      return this._sharp(output, callback);
-    }
-  }
-  return this;
-};
-
-// Deprecated to make way for future stream support - remove in v0.6.0
-Sharp.prototype.write = require('util').deprecate(
-  Sharp.prototype.toFile,
-  '.write() is deprecated and will be removed in v0.6.0. Use .toFile() instead.'
-);
-
-Sharp.prototype.toBuffer = function(callback) {
-  return this._sharp('__input', callback);
-};
-
-Sharp.prototype.jpeg = function(callback) {
-  return this._sharp('__jpeg', callback);
-};
-
-Sharp.prototype.png = function(callback) {
-  return this._sharp('__png', callback);
-};
-
-Sharp.prototype.webp = function(callback) {
-  return this._sharp('__webp', callback);
-};
-
-/*
-  Invoke the C++ image processing pipeline
-  Supports callback and promise variants
-*/
-Sharp.prototype._sharp = function(output, callback) {
-  if (typeof callback === 'function') {
-    // I like callbacks
-    sharp.resize(this.options, output, callback);
-    return this;
-  } else {
-    // I like promises
-    var options = this.options;
-    return new Promise(function(resolve, reject) {
-      sharp.resize(options, output, function(err, data) {
-        if (err) {
-          reject(err);
-        } else {
-          resolve(data);
-        }
-      });
-    });
-  }
-};
-
-module.exports.cache = function(limit) {
-  if (Number.isNaN(limit)) {
-    limit = null;
-  }
-  return sharp.cache(limit);
-};

install/dll-copy.js

@@ -0,0 +1,37 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+const libvips = require('../lib/libvips');
+
+const minimumLibvipsVersion = libvips.minimumLibvipsVersion;
+
+const platform = process.env.npm_config_platform || process.platform;
+if (platform === 'win32') {
+  const buildDir = path.join(__dirname, '..', 'build');
+  const buildReleaseDir = path.join(buildDir, 'Release');
+  libvips.log(`Creating ${buildReleaseDir}`);
+  try {
+    libvips.mkdirSync(buildDir);
+    libvips.mkdirSync(buildReleaseDir);
+  } catch (err) {}
+  const vendorLibDir = path.join(__dirname, '..', 'vendor', minimumLibvipsVersion, 'lib');
+  libvips.log(`Copying DLLs from ${vendorLibDir} to ${buildReleaseDir}`);
+  try {
+    fs
+      .readdirSync(vendorLibDir)
+      .filter(function (filename) {
+        return /\.dll$/.test(filename);
+      })
+      .forEach(function (filename) {
+        fs.copyFileSync(
+          path.join(vendorLibDir, filename),
+          path.join(buildReleaseDir, filename)
+        );
+      });
+  } catch (err) {
+    libvips.log(err);
+    process.exit(1);
+  }
+}

install/libvips.js

@@ -0,0 +1,168 @@
+'use strict';
+
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+const stream = require('stream');
+const zlib = require('zlib');
+
+const detectLibc = require('detect-libc');
+const semver = require('semver');
+const simpleGet = require('simple-get');
+const tarFs = require('tar-fs');
+
+const agent = require('../lib/agent');
+const libvips = require('../lib/libvips');
+const platform = require('../lib/platform');
+
+const minimumGlibcVersionByArch = {
+  arm: '2.28',
+  arm64: '2.29',
+  x64: '2.17'
+};
+
+const hasSharpPrebuild = [
+  'darwin-x64',
+  'linux-arm64',
+  'linux-x64',
+  'linuxmusl-x64',
+  'linuxmusl-arm64',
+  'win32-ia32',
+  'win32-x64'
+];
+
+const { minimumLibvipsVersion, minimumLibvipsVersionLabelled } = libvips;
+const distHost = process.env.npm_config_sharp_libvips_binary_host || 'https://github.com/lovell/sharp-libvips/releases/download';
+const distBaseUrl = process.env.npm_config_sharp_dist_base_url || process.env.SHARP_DIST_BASE_URL || `${distHost}/v${minimumLibvipsVersionLabelled}/`;
+const supportsBrotli = ('BrotliDecompress' in zlib);
+
+const fail = function (err) {
+  libvips.log(err);
+  if (err.code === 'EACCES') {
+    libvips.log('Are you trying to install as a root or sudo user? Try again with the --unsafe-perm flag');
+  }
+  libvips.log('Attempting to build from source via node-gyp but this may fail due to the above error');
+  libvips.log('Please see https://sharp.pixelplumbing.com/install for required dependencies');
+  process.exit(1);
+};
+
+const extractTarball = function (tarPath, platformAndArch) {
+  const vendorPath = path.join(__dirname, '..', 'vendor');
+  libvips.mkdirSync(vendorPath);
+  const versionedVendorPath = path.join(vendorPath, minimumLibvipsVersion);
+  libvips.mkdirSync(versionedVendorPath);
+
+  const ignoreVendorInclude = hasSharpPrebuild.includes(platformAndArch) && !process.env.npm_config_build_from_source;
+  const ignore = function (name) {
+    return ignoreVendorInclude && name.includes('include/');
+  };
+
+  stream.pipeline(
+    fs.createReadStream(tarPath),
+    supportsBrotli ? new zlib.BrotliDecompress() : new zlib.Gunzip(),
+    tarFs.extract(versionedVendorPath, { ignore }),
+    function (err) {
+      if (err) {
+        if (/unexpected end of file/.test(err.message)) {
+          fail(new Error(`Please delete ${tarPath} as it is not a valid tarball`));
+        }
+        fail(err);
+      }
+    }
+  );
+};
+
+try {
+  const useGlobalLibvips = libvips.useGlobalLibvips();
+
+  if (useGlobalLibvips) {
+    const globalLibvipsVersion = libvips.globalLibvipsVersion();
+    libvips.log(`Detected globally-installed libvips v${globalLibvipsVersion}`);
+    libvips.log('Building from source via node-gyp');
+    process.exit(1);
+  } else if (libvips.hasVendoredLibvips()) {
+    libvips.log(`Using existing vendored libvips v${minimumLibvipsVersion}`);
+  } else {
+    // Is this arch/platform supported?
+    const arch = process.env.npm_config_arch || process.arch;
+    const platformAndArch = platform();
+    if (arch === 'ia32' && !platformAndArch.startsWith('win32')) {
+      throw new Error(`Intel Architecture 32-bit systems require manual installation of libvips >= ${minimumLibvipsVersion}`);
+    }
+    if (platformAndArch === 'darwin-arm64') {
+      throw new Error("Please run 'brew install vips' to install libvips on Apple M1 (ARM64) systems");
+    }
+    if (platformAndArch === 'freebsd-x64' || platformAndArch === 'openbsd-x64' || platformAndArch === 'sunos-x64') {
+      throw new Error(`BSD/SunOS systems require manual installation of libvips >= ${minimumLibvipsVersion}`);
+    }
+    if (detectLibc.family === detectLibc.GLIBC && detectLibc.version) {
+      if (semver.lt(`${detectLibc.version}.0`, `${minimumGlibcVersionByArch[arch]}.0`)) {
+        throw new Error(`Use with glibc ${detectLibc.version} requires manual installation of libvips >= ${minimumLibvipsVersion}`);
+      }
+    }
+    if (detectLibc.family === detectLibc.MUSL && detectLibc.version) {
+      if (semver.lt(detectLibc.version, '1.1.24')) {
+        throw new Error(`Use with musl ${detectLibc.version} requires manual installation of libvips >= ${minimumLibvipsVersion}`);
+      }
+    }
+
+    const supportedNodeVersion = process.env.npm_package_engines_node || require('../package.json').engines.node;
+    if (!semver.satisfies(process.versions.node, supportedNodeVersion)) {
+      throw new Error(`Expected Node.js version ${supportedNodeVersion} but found ${process.versions.node}`);
+    }
+
+    const extension = supportsBrotli ? 'br' : 'gz';
+
+    // Download to per-process temporary file
+    const tarFilename = ['libvips', minimumLibvipsVersion, platformAndArch].join('-') + '.tar.' + extension;
+    const tarPathCache = path.join(libvips.cachePath(), tarFilename);
+    if (fs.existsSync(tarPathCache)) {
+      libvips.log(`Using cached ${tarPathCache}`);
+      extractTarball(tarPathCache, platformAndArch);
+    } else {
+      const url = distBaseUrl + tarFilename;
+      libvips.log(`Downloading ${url}`);
+      simpleGet({ url: url, agent: agent() }, function (err, response) {
+        if (err) {
+          fail(err);
+        } else if (response.statusCode === 404) {
+          fail(new Error(`Prebuilt libvips ${minimumLibvipsVersion} binaries are not yet available for ${platformAndArch}`));
+        } else if (response.statusCode !== 200) {
+          fail(new Error(`Status ${response.statusCode} ${response.statusMessage}`));
+        } else {
+          const tarPathTemp = path.join(os.tmpdir(), `${process.pid}-${tarFilename}`);
+          const tmpFileStream = fs.createWriteStream(tarPathTemp);
+          response
+            .on('error', function (err) {
+              tmpFileStream.destroy(err);
+            })
+            .on('close', function () {
+              if (!response.complete) {
+                tmpFileStream.destroy(new Error('Download incomplete (connection was terminated)'));
+              }
+            })
+            .pipe(tmpFileStream);
+          tmpFileStream
+            .on('error', function (err) {
+              // Clean up temporary file
+              fs.unlinkSync(tarPathTemp);
+              fail(err);
+            })
+            .on('close', function () {
+              try {
+                // Attempt to rename
+                fs.renameSync(tarPathTemp, tarPathCache);
+              } catch (err) {
+                // Fall back to copy and unlink
+                fs.copyFileSync(tarPathTemp, tarPathCache);
+                fs.unlinkSync(tarPathTemp);
+              }
+              extractTarball(tarPathCache);
+            });
+        }
+      });
+    }
+  }
+} catch (err) {
+  fail(err);
+}

lib/agent.js

@@ -0,0 +1,40 @@
+'use strict';
+
+const url = require('url');
+const tunnelAgent = require('tunnel-agent');
+
+const is = require('./is');
+
+const proxies = [
+  'HTTPS_PROXY',
+  'https_proxy',
+  'HTTP_PROXY',
+  'http_proxy',
+  'npm_config_https_proxy',
+  'npm_config_proxy'
+];
+
+function env (key) {
+  return process.env[key];
+}
+
+module.exports = function () {
+  try {
+    const proxy = new url.URL(proxies.map(env).find(is.string));
+    const tunnel = proxy.protocol === 'https:'
+      ? tunnelAgent.httpsOverHttps
+      : tunnelAgent.httpsOverHttp;
+    const proxyAuth = proxy.username && proxy.password
+      ? `${proxy.username}:${proxy.password}`
+      : null;
+    return tunnel({
+      proxy: {
+        port: Number(proxy.port),
+        host: proxy.hostname,
+        proxyAuth
+      }
+    });
+  } catch (err) {
+    return null;
+  }
+};

lib/channel.js

@@ -0,0 +1,147 @@
+'use strict';
+
+const is = require('./is');
+
+/**
+ * Boolean operations for bandbool.
+ * @private
+ */
+const bool = {
+  and: 'and',
+  or: 'or',
+  eor: 'eor'
+};
+
+/**
+ * Remove alpha channel, if any. This is a no-op if the image does not have an alpha channel.
+ *
+ * @example
+ * sharp('rgba.png')
+ *   .removeAlpha()
+ *   .toFile('rgb.png', function(err, info) {
+ *     // rgb.png is a 3 channel image without an alpha channel
+ *   });
+ *
+ * @returns {Sharp}
+ */
+function removeAlpha () {
+  this.options.removeAlpha = true;
+  return this;
+}
+
+/**
+ * Ensure alpha channel, if missing. The added alpha channel will be fully opaque. This is a no-op if the image already has an alpha channel.
+ *
+ * @since 0.21.2
+ *
+ * @example
+ * sharp('rgb.jpg')
+ *   .ensureAlpha()
+ *   .toFile('rgba.png', function(err, info) {
+ *     // rgba.png is a 4 channel image with a fully opaque alpha channel
+ *   });
+ *
+ * @returns {Sharp}
+ */
+function ensureAlpha () {
+  this.options.ensureAlpha = true;
+  return this;
+}
+
+/**
+ * Extract a single channel from a multi-channel image.
+ *
+ * @example
+ * sharp(input)
+ *   .extractChannel('green')
+ *   .toColourspace('b-w')
+ *   .toFile('green.jpg', function(err, info) {
+ *     // info.channels === 1
+ *     // green.jpg is a greyscale image containing the green channel of the input
+ *    });
+ *
+ * @param {number|string} channel - zero-indexed channel/band number to extract, or `red`, `green`, `blue` or `alpha`.
+ * @returns {Sharp}
+ * @throws {Error} Invalid channel
+ */
+function extractChannel (channel) {
+  const channelMap = { red: 0, green: 1, blue: 2, alpha: 3 };
+  if (Object.keys(channelMap).includes(channel)) {
+    channel = channelMap[channel];
+  }
+  if (is.integer(channel) && is.inRange(channel, 0, 4)) {
+    this.options.extractChannel = channel;
+  } else {
+    throw is.invalidParameterError('channel', 'integer or one of: red, green, blue, alpha', channel);
+  }
+  return this;
+}
+
+/**
+ * Join one or more channels to the image.
+ * The meaning of the added channels depends on the output colourspace, set with `toColourspace()`.
+ * By default the output image will be web-friendly sRGB, with additional channels interpreted as alpha channels.
+ * Channel ordering follows vips convention:
+ * - sRGB: 0: Red, 1: Green, 2: Blue, 3: Alpha.
+ * - CMYK: 0: Magenta, 1: Cyan, 2: Yellow, 3: Black, 4: Alpha.
+ *
+ * Buffers may be any of the image formats supported by sharp.
+ * For raw pixel input, the `options` object should contain a `raw` attribute, which follows the format of the attribute of the same name in the `sharp()` constructor.
+ *
+ * @param {Array<string|Buffer>|string|Buffer} images - one or more images (file paths, Buffers).
+ * @param {Object} options - image options, see `sharp()` constructor.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function joinChannel (images, options) {
+  if (Array.isArray(images)) {
+    images.forEach(function (image) {
+      this.options.joinChannelIn.push(this._createInputDescriptor(image, options));
+    }, this);
+  } else {
+    this.options.joinChannelIn.push(this._createInputDescriptor(images, options));
+  }
+  return this;
+}
+
+/**
+ * Perform a bitwise boolean operation on all input image channels (bands) to produce a single channel output image.
+ *
+ * @example
+ * sharp('3-channel-rgb-input.png')
+ *   .bandbool(sharp.bool.and)
+ *   .toFile('1-channel-output.png', function (err, info) {
+ *     // The output will be a single channel image where each pixel `P = R & G & B`.
+ *     // If `I(1,1) = [247, 170, 14] = [0b11110111, 0b10101010, 0b00001111]`
+ *     // then `O(1,1) = 0b11110111 & 0b10101010 & 0b00001111 = 0b00000010 = 2`.
+ *   });
+ *
+ * @param {string} boolOp - one of `and`, `or` or `eor` to perform that bitwise operation, like the C logic operators `&`, `|` and `^` respectively.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function bandbool (boolOp) {
+  if (is.string(boolOp) && is.inArray(boolOp, ['and', 'or', 'eor'])) {
+    this.options.bandBoolOp = boolOp;
+  } else {
+    throw is.invalidParameterError('boolOp', 'one of: and, or, eor', boolOp);
+  }
+  return this;
+}
+
+/**
+ * Decorate the Sharp prototype with channel-related functions.
+ * @private
+ */
+module.exports = function (Sharp) {
+  Object.assign(Sharp.prototype, {
+    // Public instance functions
+    removeAlpha,
+    ensureAlpha,
+    extractChannel,
+    joinChannel,
+    bandbool
+  });
+  // Class attributes
+  Sharp.bool = bool;
+};

lib/colour.js

@@ -0,0 +1,130 @@
+'use strict';
+
+const color = require('color');
+const is = require('./is');
+
+/**
+ * Colourspaces.
+ * @private
+ */
+const colourspace = {
+  multiband: 'multiband',
+  'b-w': 'b-w',
+  bw: 'b-w',
+  cmyk: 'cmyk',
+  srgb: 'srgb'
+};
+
+/**
+ * Tint the image using the provided chroma while preserving the image luminance.
+ * An alpha channel may be present and will be unchanged by the operation.
+ *
+ * @param {string|Object} rgb - parsed by the [color](https://www.npmjs.org/package/color) module to extract chroma values.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameter
+ */
+function tint (rgb) {
+  const colour = color(rgb);
+  this.options.tintA = colour.a();
+  this.options.tintB = colour.b();
+  return this;
+}
+
+/**
+ * Convert to 8-bit greyscale; 256 shades of grey.
+ * This is a linear operation. If the input image is in a non-linear colour space such as sRGB, use `gamma()` with `greyscale()` for the best results.
+ * By default the output image will be web-friendly sRGB and contain three (identical) color channels.
+ * This may be overridden by other sharp operations such as `toColourspace('b-w')`,
+ * which will produce an output image containing one color channel.
+ * An alpha channel may be present, and will be unchanged by the operation.
+ * @param {Boolean} [greyscale=true]
+ * @returns {Sharp}
+ */
+function greyscale (greyscale) {
+  this.options.greyscale = is.bool(greyscale) ? greyscale : true;
+  return this;
+}
+
+/**
+ * Alternative spelling of `greyscale`.
+ * @param {Boolean} [grayscale=true]
+ * @returns {Sharp}
+ */
+function grayscale (grayscale) {
+  return this.greyscale(grayscale);
+}
+
+/**
+ * Set the output colourspace.
+ * By default output image will be web-friendly sRGB, with additional channels interpreted as alpha channels.
+ *
+ * @example
+ * // Output 16 bits per pixel RGB
+ * await sharp(input)
+ *  .toColourspace('rgb16')
+ *  .toFile('16-bpp.png')
+ *
+ * @param {string} [colourspace] - output colourspace e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...](https://github.com/libvips/libvips/blob/master/libvips/iofuncs/enumtypes.c#L568)
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function toColourspace (colourspace) {
+  if (!is.string(colourspace)) {
+    throw is.invalidParameterError('colourspace', 'string', colourspace);
+  }
+  this.options.colourspace = colourspace;
+  return this;
+}
+
+/**
+ * Alternative spelling of `toColourspace`.
+ * @param {string} [colorspace] - output colorspace.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function toColorspace (colorspace) {
+  return this.toColourspace(colorspace);
+}
+
+/**
+ * Update a colour attribute of the this.options Object.
+ * @private
+ * @param {string} key
+ * @param {string|Object} value
+ * @throws {Error} Invalid value
+ */
+function _setBackgroundColourOption (key, value) {
+  if (is.defined(value)) {
+    if (is.object(value) || is.string(value)) {
+      const colour = color(value);
+      this.options[key] = [
+        colour.red(),
+        colour.green(),
+        colour.blue(),
+        Math.round(colour.alpha() * 255)
+      ];
+    } else {
+      throw is.invalidParameterError('background', 'object or string', value);
+    }
+  }
+}
+
+/**
+ * Decorate the Sharp prototype with colour-related functions.
+ * @private
+ */
+module.exports = function (Sharp) {
+  Object.assign(Sharp.prototype, {
+    // Public
+    tint,
+    greyscale,
+    grayscale,
+    toColourspace,
+    toColorspace,
+    // Private
+    _setBackgroundColourOption
+  });
+  // Class attributes
+  Sharp.colourspace = colourspace;
+  Sharp.colorspace = colourspace;
+};

lib/composite.js

@@ -0,0 +1,176 @@
+'use strict';
+
+const is = require('./is');
+
+/**
+ * Blend modes.
+ * @member
+ * @private
+ */
+const blend = {
+  clear: 'clear',
+  source: 'source',
+  over: 'over',
+  in: 'in',
+  out: 'out',
+  atop: 'atop',
+  dest: 'dest',
+  'dest-over': 'dest-over',
+  'dest-in': 'dest-in',
+  'dest-out': 'dest-out',
+  'dest-atop': 'dest-atop',
+  xor: 'xor',
+  add: 'add',
+  saturate: 'saturate',
+  multiply: 'multiply',
+  screen: 'screen',
+  overlay: 'overlay',
+  darken: 'darken',
+  lighten: 'lighten',
+  'colour-dodge': 'colour-dodge',
+  'color-dodge': 'colour-dodge',
+  'colour-burn': 'colour-burn',
+  'color-burn': 'colour-burn',
+  'hard-light': 'hard-light',
+  'soft-light': 'soft-light',
+  difference: 'difference',
+  exclusion: 'exclusion'
+};
+
+/**
+ * Composite image(s) over the processed (resized, extracted etc.) image.
+ *
+ * The images to composite must be the same size or smaller than the processed image.
+ * If both `top` and `left` options are provided, they take precedence over `gravity`.
+ *
+ * The `blend` option can be one of `clear`, `source`, `over`, `in`, `out`, `atop`,
+ * `dest`, `dest-over`, `dest-in`, `dest-out`, `dest-atop`,
+ * `xor`, `add`, `saturate`, `multiply`, `screen`, `overlay`, `darken`, `lighten`,
+ * `colour-dodge`, `color-dodge`, `colour-burn`,`color-burn`,
+ * `hard-light`, `soft-light`, `difference`, `exclusion`.
+ *
+ * More information about blend modes can be found at
+ * https://libvips.github.io/libvips/API/current/libvips-conversion.html#VipsBlendMode
+ * and https://www.cairographics.org/operators/
+ *
+ * @since 0.22.0
+ *
+ * @example
+ * sharp('input.png')
+ *   .rotate(180)
+ *   .resize(300)
+ *   .flatten( { background: '#ff6600' } )
+ *   .composite([{ input: 'overlay.png', gravity: 'southeast' }])
+ *   .sharpen()
+ *   .withMetadata()
+ *   .webp( { quality: 90 } )
+ *   .toBuffer()
+ *   .then(function(outputBuffer) {
+ *     // outputBuffer contains upside down, 300px wide, alpha channel flattened
+ *     // onto orange background, composited with overlay.png with SE gravity,
+ *     // sharpened, with metadata, 90% quality WebP image data. Phew!
+ *   });
+ *
+ * @param {Object[]} images - Ordered list of images to composite
+ * @param {Buffer|String} [images[].input] - Buffer containing image data, String containing the path to an image file, or Create object (see below)
+ * @param {Object} [images[].input.create] - describes a blank overlay to be created.
+ * @param {Number} [images[].input.create.width]
+ * @param {Number} [images[].input.create.height]
+ * @param {Number} [images[].input.create.channels] - 3-4
+ * @param {String|Object} [images[].input.create.background] - parsed by the [color](https://www.npmjs.org/package/color) module to extract values for red, green, blue and alpha.
+ * @param {String} [images[].blend='over'] - how to blend this image with the image below.
+ * @param {String} [images[].gravity='centre'] - gravity at which to place the overlay.
+ * @param {Number} [images[].top] - the pixel offset from the top edge.
+ * @param {Number} [images[].left] - the pixel offset from the left edge.
+ * @param {Boolean} [images[].tile=false] - set to true to repeat the overlay image across the entire image with the given `gravity`.
+ * @param {Boolean} [images[].premultiplied=false] - set to true to avoid premultipling the image below. Equivalent to the `--premultiplied` vips option.
+ * @param {Number} [images[].density=72] - number representing the DPI for vector overlay image.
+ * @param {Object} [images[].raw] - describes overlay when using raw pixel data.
+ * @param {Number} [images[].raw.width]
+ * @param {Number} [images[].raw.height]
+ * @param {Number} [images[].raw.channels]
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function composite (images) {
+  if (!Array.isArray(images)) {
+    throw is.invalidParameterError('images to composite', 'array', images);
+  }
+  this.options.composite = images.map(image => {
+    if (!is.object(image)) {
+      throw is.invalidParameterError('image to composite', 'object', image);
+    }
+    const inputOptions = this._inputOptionsFromObject(image);
+    const composite = {
+      input: this._createInputDescriptor(image.input, inputOptions, { allowStream: false }),
+      blend: 'over',
+      tile: false,
+      left: 0,
+      top: 0,
+      hasOffset: false,
+      gravity: 0,
+      premultiplied: false
+    };
+    if (is.defined(image.blend)) {
+      if (is.string(blend[image.blend])) {
+        composite.blend = blend[image.blend];
+      } else {
+        throw is.invalidParameterError('blend', 'valid blend name', image.blend);
+      }
+    }
+    if (is.defined(image.tile)) {
+      if (is.bool(image.tile)) {
+        composite.tile = image.tile;
+      } else {
+        throw is.invalidParameterError('tile', 'boolean', image.tile);
+      }
+    }
+    if (is.defined(image.left)) {
+      if (is.integer(image.left)) {
+        composite.left = image.left;
+      } else {
+        throw is.invalidParameterError('left', 'integer', image.left);
+      }
+    }
+    if (is.defined(image.top)) {
+      if (is.integer(image.top)) {
+        composite.top = image.top;
+      } else {
+        throw is.invalidParameterError('top', 'integer', image.top);
+      }
+    }
+    if (is.defined(image.top) !== is.defined(image.left)) {
+      throw new Error('Expected both left and top to be set');
+    } else {
+      composite.hasOffset = is.integer(image.top) && is.integer(image.left);
+    }
+    if (is.defined(image.gravity)) {
+      if (is.integer(image.gravity) && is.inRange(image.gravity, 0, 8)) {
+        composite.gravity = image.gravity;
+      } else if (is.string(image.gravity) && is.integer(this.constructor.gravity[image.gravity])) {
+        composite.gravity = this.constructor.gravity[image.gravity];
+      } else {
+        throw is.invalidParameterError('gravity', 'valid gravity', image.gravity);
+      }
+    }
+    if (is.defined(image.premultiplied)) {
+      if (is.bool(image.premultiplied)) {
+        composite.premultiplied = image.premultiplied;
+      } else {
+        throw is.invalidParameterError('premultiplied', 'boolean', image.premultiplied);
+      }
+    }
+
+    return composite;
+  });
+  return this;
+}
+
+/**
+ * Decorate the Sharp prototype with composite-related functions.
+ * @private
+ */
+module.exports = function (Sharp) {
+  Sharp.prototype.composite = composite;
+  Sharp.blend = blend;
+};

lib/constructor.js

@@ -0,0 +1,384 @@
+'use strict';
+
+const util = require('util');
+const stream = require('stream');
+const is = require('./is');
+
+require('./libvips').hasVendoredLibvips();
+
+/* istanbul ignore next */
+try {
+  require('../build/Release/sharp.node');
+} catch (err) {
+  // Bail early if bindings aren't available
+  const help = ['', 'Something went wrong installing the "sharp" module', '', err.message, ''];
+  if (/NODE_MODULE_VERSION/.test(err.message)) {
+    help.push('- Ensure the version of Node.js used at install time matches that used at runtime');
+  } else if (/invalid ELF header/.test(err.message)) {
+    help.push(`- Ensure "${process.platform}" is used at install time as well as runtime`);
+  } else if (/dylib/.test(err.message) && /Incompatible library version/.test(err.message)) {
+    help.push('- Run "brew update && brew upgrade vips"');
+  } else {
+    help.push(
+      '- Remove the "node_modules/sharp" directory then run',
+      '  "npm install --ignore-scripts=false --verbose sharp" and look for errors'
+    );
+  }
+  help.push(
+    '- Consult the installation documentation at https://sharp.pixelplumbing.com/install',
+    '- Search for this error at https://github.com/lovell/sharp/issues', ''
+  );
+  const error = help.join('\n');
+  throw new Error(error);
+}
+
+// Use NODE_DEBUG=sharp to enable libvips warnings
+const debuglog = util.debuglog('sharp');
+
+/**
+ * Constructor factory to create an instance of `sharp`, to which further methods are chained.
+ *
+ * JPEG, PNG, WebP, AVIF or TIFF format image data can be streamed out from this object.
+ * When using Stream based output, derived attributes are available from the `info` event.
+ *
+ * Non-critical problems encountered during processing are emitted as `warning` events.
+ *
+ * Implements the [stream.Duplex](http://nodejs.org/api/stream.html#stream_class_stream_duplex) class.
+ *
+ * @constructs Sharp
+ *
+ * @emits Sharp#info
+ * @emits Sharp#warning
+ *
+ * @example
+ * sharp('input.jpg')
+ *   .resize(300, 200)
+ *   .toFile('output.jpg', function(err) {
+ *     // output.jpg is a 300 pixels wide and 200 pixels high image
+ *     // containing a scaled and cropped version of input.jpg
+ *   });
+ *
+ * @example
+ * // Read image data from readableStream,
+ * // resize to 300 pixels wide,
+ * // emit an 'info' event with calculated dimensions
+ * // and finally write image data to writableStream
+ * var transformer = sharp()
+ *   .resize(300)
+ *   .on('info', function(info) {
+ *     console.log('Image height is ' + info.height);
+ *   });
+ * readableStream.pipe(transformer).pipe(writableStream);
+ *
+ * @example
+ * // Create a blank 300x200 PNG image of semi-transluent red pixels
+ * sharp({
+ *   create: {
+ *     width: 300,
+ *     height: 200,
+ *     channels: 4,
+ *     background: { r: 255, g: 0, b: 0, alpha: 0.5 }
+ *   }
+ * })
+ * .png()
+ * .toBuffer()
+ * .then( ... );
+ *
+ * @example
+ * // Convert an animated GIF to an animated WebP
+ * await sharp('in.gif', { animated: true }).toFile('out.webp');
+ *
+ * @example
+ * // Read a raw array of pixels and save it to a png
+ * const input = Uint8Array.from([255, 255, 255, 0, 0, 0]); // or Uint8ClampedArray
+ * const image = sharp(input, {
+ *   // because the input does not contain its dimensions or how many channels it has
+ *   // we need to specify it in the constructor options
+ *   raw: {
+ *     width: 2,
+ *     height: 1,
+ *     channels: 3
+ *   }
+ * });
+ * await image.toFile('my-two-pixels.png');
+ *
+ * @example
+ * // Generate RGB Gaussian noise
+ * await sharp({
+ *   create: {
+ *     width: 300,
+ *     height: 200,
+ *     channels: 3,
+ *     noise: {
+ *       type: 'gaussian',
+ *       mean: 128,
+ *       sigma: 30
+ *     }
+ *  }
+ * }).toFile('noise.png');
+ *
+ * @param {(Buffer|Uint8Array|Uint8ClampedArray|string)} [input] - if present, can be
+ *  a Buffer / Uint8Array / Uint8ClampedArray containing JPEG, PNG, WebP, AVIF, GIF, SVG, TIFF or raw pixel image data, or
+ *  a String containing the filesystem path to an JPEG, PNG, WebP, AVIF, GIF, SVG or TIFF image file.
+ *  JPEG, PNG, WebP, AVIF, GIF, SVG, TIFF or raw pixel image data can be streamed into the object when not present.
+ * @param {Object} [options] - if present, is an Object with optional attributes.
+ * @param {boolean} [options.failOnError=true] - by default halt processing and raise an error when loading invalid images.
+ *  Set this flag to `false` if you'd rather apply a "best effort" to decode images, even if the data is corrupt or invalid.
+ * @param {number|boolean} [options.limitInputPixels=268402689] - Do not process input images where the number of pixels
+ *  (width x height) exceeds this limit. Assumes image dimensions contained in the input metadata can be trusted.
+ *  An integral Number of pixels, zero or false to remove limit, true to use default limit of 268402689 (0x3FFF x 0x3FFF).
+ * @param {boolean} [options.sequentialRead=false] - Set this to `true` to use sequential rather than random access where possible.
+ *  This can reduce memory usage and might improve performance on some systems.
+ * @param {number} [options.density=72] - number representing the DPI for vector images in the range 1 to 100000.
+ * @param {number} [options.pages=1] - number of pages to extract for multi-page input (GIF, WebP, AVIF, TIFF, PDF), use -1 for all pages.
+ * @param {number} [options.page=0] - page number to start extracting from for multi-page input (GIF, WebP, AVIF, TIFF, PDF), zero based.
+ * @param {number} [options.level=0] - level to extract from a multi-level input (OpenSlide), zero based.
+ * @param {boolean} [options.animated=false] - Set to `true` to read all frames/pages of an animated image (equivalent of setting `pages` to `-1`).
+ * @param {Object} [options.raw] - describes raw pixel input image data. See `raw()` for pixel ordering.
+ * @param {number} [options.raw.width] - integral number of pixels wide.
+ * @param {number} [options.raw.height] - integral number of pixels high.
+ * @param {number} [options.raw.channels] - integral number of channels, between 1 and 4.
+ * @param {Object} [options.create] - describes a new image to be created.
+ * @param {number} [options.create.width] - integral number of pixels wide.
+ * @param {number} [options.create.height] - integral number of pixels high.
+ * @param {number} [options.create.channels] - integral number of channels, either 3 (RGB) or 4 (RGBA).
+ * @param {string|Object} [options.create.background] - parsed by the [color](https://www.npmjs.org/package/color) module to extract values for red, green, blue and alpha.
+ * @param {Object} [options.create.noise] - describes a noise to be created.
+ * @param {string} [options.create.noise.type] - type of generated noise, currently only `gaussian` is supported.
+ * @param {number} [options.create.noise.mean] - mean of pixels in generated noise.
+ * @param {number} [options.create.noise.sigma] - standard deviation of pixels in generated noise.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+const Sharp = function (input, options) {
+  if (arguments.length === 1 && !is.defined(input)) {
+    throw new Error('Invalid input');
+  }
+  if (!(this instanceof Sharp)) {
+    return new Sharp(input, options);
+  }
+  stream.Duplex.call(this);
+  this.options = {
+    // resize options
+    topOffsetPre: -1,
+    leftOffsetPre: -1,
+    widthPre: -1,
+    heightPre: -1,
+    topOffsetPost: -1,
+    leftOffsetPost: -1,
+    widthPost: -1,
+    heightPost: -1,
+    width: -1,
+    height: -1,
+    canvas: 'crop',
+    position: 0,
+    resizeBackground: [0, 0, 0, 255],
+    useExifOrientation: false,
+    angle: 0,
+    rotationAngle: 0,
+    rotationBackground: [0, 0, 0, 255],
+    rotateBeforePreExtract: false,
+    flip: false,
+    flop: false,
+    extendTop: 0,
+    extendBottom: 0,
+    extendLeft: 0,
+    extendRight: 0,
+    extendBackground: [0, 0, 0, 255],
+    withoutEnlargement: false,
+    affineMatrix: [],
+    affineBackground: [0, 0, 0, 255],
+    affineIdx: 0,
+    affineIdy: 0,
+    affineOdx: 0,
+    affineOdy: 0,
+    affineInterpolator: this.constructor.interpolators.bilinear,
+    kernel: 'lanczos3',
+    fastShrinkOnLoad: true,
+    // operations
+    tintA: 128,
+    tintB: 128,
+    flatten: false,
+    flattenBackground: [0, 0, 0],
+    negate: false,
+    medianSize: 0,
+    blurSigma: 0,
+    sharpenSigma: 0,
+    sharpenFlat: 1,
+    sharpenJagged: 2,
+    threshold: 0,
+    thresholdGrayscale: true,
+    trimThreshold: 0,
+    gamma: 0,
+    gammaOut: 0,
+    greyscale: false,
+    normalise: false,
+    brightness: 1,
+    saturation: 1,
+    hue: 0,
+    booleanBufferIn: null,
+    booleanFileIn: '',
+    joinChannelIn: [],
+    extractChannel: -1,
+    removeAlpha: false,
+    ensureAlpha: false,
+    colourspace: 'srgb',
+    composite: [],
+    // output
+    fileOut: '',
+    formatOut: 'input',
+    streamOut: false,
+    withMetadata: false,
+    withMetadataOrientation: -1,
+    withMetadataIcc: '',
+    resolveWithObject: false,
+    // output format
+    jpegQuality: 80,
+    jpegProgressive: false,
+    jpegChromaSubsampling: '4:2:0',
+    jpegTrellisQuantisation: false,
+    jpegOvershootDeringing: false,
+    jpegOptimiseScans: false,
+    jpegOptimiseCoding: true,
+    jpegQuantisationTable: 0,
+    pngProgressive: false,
+    pngCompressionLevel: 6,
+    pngAdaptiveFiltering: false,
+    pngPalette: false,
+    pngQuality: 100,
+    pngColours: 256,
+    pngDither: 1,
+    webpQuality: 80,
+    webpAlphaQuality: 100,
+    webpLossless: false,
+    webpNearLossless: false,
+    webpSmartSubsample: false,
+    webpReductionEffort: 4,
+    tiffQuality: 80,
+    tiffCompression: 'jpeg',
+    tiffPredictor: 'horizontal',
+    tiffPyramid: false,
+    tiffBitdepth: 8,
+    tiffTile: false,
+    tiffTileHeight: 256,
+    tiffTileWidth: 256,
+    tiffXres: 1.0,
+    tiffYres: 1.0,
+    heifQuality: 50,
+    heifLossless: false,
+    heifCompression: 'av1',
+    heifSpeed: 5,
+    heifChromaSubsampling: '4:2:0',
+    tileSize: 256,
+    tileOverlap: 0,
+    tileContainer: 'fs',
+    tileLayout: 'dz',
+    tileFormat: 'last',
+    tileDepth: 'last',
+    tileAngle: 0,
+    tileSkipBlanks: -1,
+    tileBackground: [255, 255, 255, 255],
+    tileCentre: false,
+    tileId: 'https://example.com/iiif',
+    linearA: 1,
+    linearB: 0,
+    // Function to notify of libvips warnings
+    debuglog: warning => {
+      this.emit('warning', warning);
+      debuglog(warning);
+    },
+    // Function to notify of queue length changes
+    queueListener: function (queueLength) {
+      Sharp.queue.emit('change', queueLength);
+    }
+  };
+  this.options.input = this._createInputDescriptor(input, options, { allowStream: true });
+  return this;
+};
+util.inherits(Sharp, stream.Duplex);
+
+/**
+ * Take a "snapshot" of the Sharp instance, returning a new instance.
+ * Cloned instances inherit the input of their parent instance.
+ * This allows multiple output Streams and therefore multiple processing pipelines to share a single input Stream.
+ *
+ * @example
+ * const pipeline = sharp().rotate();
+ * pipeline.clone().resize(800, 600).pipe(firstWritableStream);
+ * pipeline.clone().extract({ left: 20, top: 20, width: 100, height: 100 }).pipe(secondWritableStream);
+ * readableStream.pipe(pipeline);
+ * // firstWritableStream receives auto-rotated, resized readableStream
+ * // secondWritableStream receives auto-rotated, extracted region of readableStream
+ *
+ * @example
+ * // Create a pipeline that will download an image, resize it and format it to different files
+ * // Using Promises to know when the pipeline is complete
+ * const fs = require("fs");
+ * const got = require("got");
+ * const sharpStream = sharp({
+ *   failOnError: false
+ * });
+ *
+ * const promises = [];
+ *
+ * promises.push(
+ *   sharpStream
+ *     .clone()
+ *     .jpeg({ quality: 100 })
+ *     .toFile("originalFile.jpg")
+ * );
+ *
+ * promises.push(
+ *   sharpStream
+ *     .clone()
+ *     .resize({ width: 500 })
+ *     .jpeg({ quality: 80 })
+ *     .toFile("optimized-500.jpg")
+ * );
+ *
+ * promises.push(
+ *   sharpStream
+ *     .clone()
+ *     .resize({ width: 500 })
+ *     .webp({ quality: 80 })
+ *     .toFile("optimized-500.webp")
+ * );
+ *
+ * // https://github.com/sindresorhus/got#gotstreamurl-options
+ * got.stream("https://www.example.com/some-file.jpg").pipe(sharpStream);
+ *
+ * Promise.all(promises)
+ *   .then(res => { console.log("Done!", res); })
+ *   .catch(err => {
+ *     console.error("Error processing files, let's clean it up", err);
+ *     try {
+ *       fs.unlinkSync("originalFile.jpg");
+ *       fs.unlinkSync("optimized-500.jpg");
+ *       fs.unlinkSync("optimized-500.webp");
+ *     } catch (e) {}
+ *   });
+ *
+ * @returns {Sharp}
+ */
+function clone () {
+  // Clone existing options
+  const clone = this.constructor.call();
+  clone.options = Object.assign({}, this.options);
+  // Pass 'finish' event to clone for Stream-based input
+  if (this._isStreamInput()) {
+    this.on('finish', () => {
+      // Clone inherits input data
+      this._flattenBufferIn();
+      clone.options.bufferIn = this.options.bufferIn;
+      clone.emit('finish');
+    });
+  }
+  return clone;
+}
+Object.assign(Sharp.prototype, { clone });
+
+/**
+ * Export constructor.
+ * @private
+ */
+module.exports = Sharp;

lib/index.js

@@ -0,0 +1,13 @@
+'use strict';
+
+const Sharp = require('./constructor');
+require('./input')(Sharp);
+require('./resize')(Sharp);
+require('./composite')(Sharp);
+require('./operation')(Sharp);
+require('./colour')(Sharp);
+require('./channel')(Sharp);
+require('./output')(Sharp);
+require('./utility')(Sharp);
+
+module.exports = Sharp;

lib/input.js

@@ -0,0 +1,413 @@
+'use strict';
+
+const color = require('color');
+const is = require('./is');
+const sharp = require('../build/Release/sharp.node');
+
+/**
+ * Extract input options, if any, from an object.
+ * @private
+ */
+function _inputOptionsFromObject (obj) {
+  const { raw, density, limitInputPixels, sequentialRead, failOnError, animated, page, pages } = obj;
+  return [raw, density, limitInputPixels, sequentialRead, failOnError, animated, page, pages].some(is.defined)
+    ? { raw, density, limitInputPixels, sequentialRead, failOnError, animated, page, pages }
+    : undefined;
+}
+
+/**
+ * Create Object containing input and input-related options.
+ * @private
+ */
+function _createInputDescriptor (input, inputOptions, containerOptions) {
+  const inputDescriptor = {
+    failOnError: true,
+    limitInputPixels: Math.pow(0x3FFF, 2),
+    sequentialRead: false
+  };
+  if (is.string(input)) {
+    // filesystem
+    inputDescriptor.file = input;
+  } else if (is.buffer(input)) {
+    // Buffer
+    inputDescriptor.buffer = input;
+  } else if (is.uint8Array(input)) {
+    // Uint8Array or Uint8ClampedArray
+    inputDescriptor.buffer = Buffer.from(input.buffer);
+  } else if (is.plainObject(input) && !is.defined(inputOptions)) {
+    // Plain Object descriptor, e.g. create
+    inputOptions = input;
+    if (_inputOptionsFromObject(inputOptions)) {
+      // Stream with options
+      inputDescriptor.buffer = [];
+    }
+  } else if (!is.defined(input) && !is.defined(inputOptions) && is.object(containerOptions) && containerOptions.allowStream) {
+    // Stream without options
+    inputDescriptor.buffer = [];
+  } else {
+    throw new Error(`Unsupported input '${input}' of type ${typeof input}${
+      is.defined(inputOptions) ? ` when also providing options of type ${typeof inputOptions}` : ''
+    }`);
+  }
+  if (is.object(inputOptions)) {
+    // Fail on error
+    if (is.defined(inputOptions.failOnError)) {
+      if (is.bool(inputOptions.failOnError)) {
+        inputDescriptor.failOnError = inputOptions.failOnError;
+      } else {
+        throw is.invalidParameterError('failOnError', 'boolean', inputOptions.failOnError);
+      }
+    }
+    // Density
+    if (is.defined(inputOptions.density)) {
+      if (is.inRange(inputOptions.density, 1, 100000)) {
+        inputDescriptor.density = inputOptions.density;
+      } else {
+        throw is.invalidParameterError('density', 'number between 1 and 100000', inputOptions.density);
+      }
+    }
+    // limitInputPixels
+    if (is.defined(inputOptions.limitInputPixels)) {
+      if (is.bool(inputOptions.limitInputPixels)) {
+        inputDescriptor.limitInputPixels = inputOptions.limitInputPixels
+          ? Math.pow(0x3FFF, 2)
+          : 0;
+      } else if (is.integer(inputOptions.limitInputPixels) && inputOptions.limitInputPixels >= 0) {
+        inputDescriptor.limitInputPixels = inputOptions.limitInputPixels;
+      } else {
+        throw is.invalidParameterError('limitInputPixels', 'integer >= 0', inputOptions.limitInputPixels);
+      }
+    }
+    // sequentialRead
+    if (is.defined(inputOptions.sequentialRead)) {
+      if (is.bool(inputOptions.sequentialRead)) {
+        inputDescriptor.sequentialRead = inputOptions.sequentialRead;
+      } else {
+        throw is.invalidParameterError('sequentialRead', 'boolean', inputOptions.sequentialRead);
+      }
+    }
+    // Raw pixel input
+    if (is.defined(inputOptions.raw)) {
+      if (
+        is.object(inputOptions.raw) &&
+        is.integer(inputOptions.raw.width) && inputOptions.raw.width > 0 &&
+        is.integer(inputOptions.raw.height) && inputOptions.raw.height > 0 &&
+        is.integer(inputOptions.raw.channels) && is.inRange(inputOptions.raw.channels, 1, 4)
+      ) {
+        inputDescriptor.rawWidth = inputOptions.raw.width;
+        inputDescriptor.rawHeight = inputOptions.raw.height;
+        inputDescriptor.rawChannels = inputOptions.raw.channels;
+      } else {
+        throw new Error('Expected width, height and channels for raw pixel input');
+      }
+    }
+    // Multi-page input (GIF, TIFF, PDF)
+    if (is.defined(inputOptions.animated)) {
+      if (is.bool(inputOptions.animated)) {
+        inputDescriptor.pages = inputOptions.animated ? -1 : 1;
+      } else {
+        throw is.invalidParameterError('animated', 'boolean', inputOptions.animated);
+      }
+    }
+    if (is.defined(inputOptions.pages)) {
+      if (is.integer(inputOptions.pages) && is.inRange(inputOptions.pages, -1, 100000)) {
+        inputDescriptor.pages = inputOptions.pages;
+      } else {
+        throw is.invalidParameterError('pages', 'integer between -1 and 100000', inputOptions.pages);
+      }
+    }
+    if (is.defined(inputOptions.page)) {
+      if (is.integer(inputOptions.page) && is.inRange(inputOptions.page, 0, 100000)) {
+        inputDescriptor.page = inputOptions.page;
+      } else {
+        throw is.invalidParameterError('page', 'integer between 0 and 100000', inputOptions.page);
+      }
+    }
+    // Multi-level input (OpenSlide)
+    if (is.defined(inputOptions.level)) {
+      if (is.integer(inputOptions.level) && is.inRange(inputOptions.level, 0, 256)) {
+        inputDescriptor.level = inputOptions.level;
+      } else {
+        throw is.invalidParameterError('level', 'integer between 0 and 256', inputOptions.level);
+      }
+    }
+    // Create new image
+    if (is.defined(inputOptions.create)) {
+      if (
+        is.object(inputOptions.create) &&
+        is.integer(inputOptions.create.width) && inputOptions.create.width > 0 &&
+        is.integer(inputOptions.create.height) && inputOptions.create.height > 0 &&
+        is.integer(inputOptions.create.channels)
+      ) {
+        inputDescriptor.createWidth = inputOptions.create.width;
+        inputDescriptor.createHeight = inputOptions.create.height;
+        inputDescriptor.createChannels = inputOptions.create.channels;
+        // Noise
+        if (is.defined(inputOptions.create.noise)) {
+          if (!is.object(inputOptions.create.noise)) {
+            throw new Error('Expected noise to be an object');
+          }
+          if (!is.inArray(inputOptions.create.noise.type, ['gaussian'])) {
+            throw new Error('Only gaussian noise is supported at the moment');
+          }
+          if (!is.inRange(inputOptions.create.channels, 1, 4)) {
+            throw is.invalidParameterError('create.channels', 'number between 1 and 4', inputOptions.create.channels);
+          }
+          inputDescriptor.createNoiseType = inputOptions.create.noise.type;
+          if (is.number(inputOptions.create.noise.mean) && is.inRange(inputOptions.create.noise.mean, 0, 10000)) {
+            inputDescriptor.createNoiseMean = inputOptions.create.noise.mean;
+          } else {
+            throw is.invalidParameterError('create.noise.mean', 'number between 0 and 10000', inputOptions.create.noise.mean);
+          }
+          if (is.number(inputOptions.create.noise.sigma) && is.inRange(inputOptions.create.noise.sigma, 0, 10000)) {
+            inputDescriptor.createNoiseSigma = inputOptions.create.noise.sigma;
+          } else {
+            throw is.invalidParameterError('create.noise.sigma', 'number between 0 and 10000', inputOptions.create.noise.sigma);
+          }
+        } else if (is.defined(inputOptions.create.background)) {
+          if (!is.inRange(inputOptions.create.channels, 3, 4)) {
+            throw is.invalidParameterError('create.channels', 'number between 3 and 4', inputOptions.create.channels);
+          }
+          const background = color(inputOptions.create.background);
+          inputDescriptor.createBackground = [
+            background.red(),
+            background.green(),
+            background.blue(),
+            Math.round(background.alpha() * 255)
+          ];
+        } else {
+          throw new Error('Expected valid noise or background to create a new input image');
+        }
+        delete inputDescriptor.buffer;
+      } else {
+        throw new Error('Expected valid width, height and channels to create a new input image');
+      }
+    }
+  } else if (is.defined(inputOptions)) {
+    throw new Error('Invalid input options ' + inputOptions);
+  }
+  return inputDescriptor;
+}
+
+/**
+ * Handle incoming Buffer chunk on Writable Stream.
+ * @private
+ * @param {Buffer} chunk
+ * @param {string} encoding - unused
+ * @param {Function} callback
+ */
+function _write (chunk, encoding, callback) {
+  /* istanbul ignore else */
+  if (Array.isArray(this.options.input.buffer)) {
+    /* istanbul ignore else */
+    if (is.buffer(chunk)) {
+      if (this.options.input.buffer.length === 0) {
+        this.on('finish', () => {
+          this.streamInFinished = true;
+        });
+      }
+      this.options.input.buffer.push(chunk);
+      callback();
+    } else {
+      callback(new Error('Non-Buffer data on Writable Stream'));
+    }
+  } else {
+    callback(new Error('Unexpected data on Writable Stream'));
+  }
+}
+
+/**
+ * Flattens the array of chunks accumulated in input.buffer.
+ * @private
+ */
+function _flattenBufferIn () {
+  if (this._isStreamInput()) {
+    this.options.input.buffer = Buffer.concat(this.options.input.buffer);
+  }
+}
+
+/**
+ * Are we expecting Stream-based input?
+ * @private
+ * @returns {boolean}
+ */
+function _isStreamInput () {
+  return Array.isArray(this.options.input.buffer);
+}
+
+/**
+ * Fast access to (uncached) image metadata without decoding any compressed image data.
+ * A `Promise` is returned when `callback` is not provided.
+ *
+ * - `format`: Name of decoder used to decompress image data e.g. `jpeg`, `png`, `webp`, `gif`, `svg`
+ * - `size`: Total size of image in bytes, for Stream and Buffer input only
+ * - `width`: Number of pixels wide (EXIF orientation is not taken into consideration)
+ * - `height`: Number of pixels high (EXIF orientation is not taken into consideration)
+ * - `space`: Name of colour space interpretation e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...](https://libvips.github.io/libvips/API/current/VipsImage.html#VipsInterpretation)
+ * - `channels`: Number of bands e.g. `3` for sRGB, `4` for CMYK
+ * - `depth`: Name of pixel depth format e.g. `uchar`, `char`, `ushort`, `float` [...](https://libvips.github.io/libvips/API/current/VipsImage.html#VipsBandFormat)
+ * - `density`: Number of pixels per inch (DPI), if present
+ * - `chromaSubsampling`: String containing JPEG chroma subsampling, `4:2:0` or `4:4:4` for RGB, `4:2:0:4` or `4:4:4:4` for CMYK
+ * - `isProgressive`: Boolean indicating whether the image is interlaced using a progressive scan
+ * - `pages`: Number of pages/frames contained within the image, with support for TIFF, HEIF, PDF, animated GIF and animated WebP
+ * - `pageHeight`: Number of pixels high each page in a multi-page image will be.
+ * - `loop`: Number of times to loop an animated image, zero refers to a continuous loop.
+ * - `delay`: Delay in ms between each page in an animated image, provided as an array of integers.
+ * - `pagePrimary`: Number of the primary page in a HEIF image
+ * - `levels`: Details of each level in a multi-level image provided as an array of objects, requires libvips compiled with support for OpenSlide
+ * - `hasProfile`: Boolean indicating the presence of an embedded ICC profile
+ * - `hasAlpha`: Boolean indicating the presence of an alpha transparency channel
+ * - `orientation`: Number value of the EXIF Orientation header, if present
+ * - `exif`: Buffer containing raw EXIF data, if present
+ * - `icc`: Buffer containing raw [ICC](https://www.npmjs.com/package/icc) profile data, if present
+ * - `iptc`: Buffer containing raw IPTC data, if present
+ * - `xmp`: Buffer containing raw XMP data, if present
+ * - `tifftagPhotoshop`: Buffer containing raw TIFFTAG_PHOTOSHOP data, if present
+ *
+ * @example
+ * const image = sharp(inputJpg);
+ * image
+ *   .metadata()
+ *   .then(function(metadata) {
+ *     return image
+ *       .resize(Math.round(metadata.width / 2))
+ *       .webp()
+ *       .toBuffer();
+ *   })
+ *   .then(function(data) {
+ *     // data contains a WebP image half the width and height of the original JPEG
+ *   });
+ *
+ * @param {Function} [callback] - called with the arguments `(err, metadata)`
+ * @returns {Promise<Object>|Sharp}
+ */
+function metadata (callback) {
+  if (is.fn(callback)) {
+    if (this._isStreamInput()) {
+      this.on('finish', () => {
+        this._flattenBufferIn();
+        sharp.metadata(this.options, callback);
+      });
+    } else {
+      sharp.metadata(this.options, callback);
+    }
+    return this;
+  } else {
+    if (this._isStreamInput()) {
+      return new Promise((resolve, reject) => {
+        this.on('finish', () => {
+          this._flattenBufferIn();
+          sharp.metadata(this.options, (err, metadata) => {
+            if (err) {
+              reject(err);
+            } else {
+              resolve(metadata);
+            }
+          });
+        });
+      });
+    } else {
+      return new Promise((resolve, reject) => {
+        sharp.metadata(this.options, (err, metadata) => {
+          if (err) {
+            reject(err);
+          } else {
+            resolve(metadata);
+          }
+        });
+      });
+    }
+  }
+}
+
+/**
+ * Access to pixel-derived image statistics for every channel in the image.
+ * A `Promise` is returned when `callback` is not provided.
+ *
+ * - `channels`: Array of channel statistics for each channel in the image. Each channel statistic contains
+ *     - `min` (minimum value in the channel)
+ *     - `max` (maximum value in the channel)
+ *     - `sum` (sum of all values in a channel)
+ *     - `squaresSum` (sum of squared values in a channel)
+ *     - `mean` (mean of the values in a channel)
+ *     - `stdev` (standard deviation for the values in a channel)
+ *     - `minX` (x-coordinate of one of the pixel where the minimum lies)
+ *     - `minY` (y-coordinate of one of the pixel where the minimum lies)
+ *     - `maxX` (x-coordinate of one of the pixel where the maximum lies)
+ *     - `maxY` (y-coordinate of one of the pixel where the maximum lies)
+ * - `isOpaque`: Is the image fully opaque? Will be `true` if the image has no alpha channel or if every pixel is fully opaque.
+ * - `entropy`: Histogram-based estimation of greyscale entropy, discarding alpha channel if any (experimental)
+ * - `sharpness`: Estimation of greyscale sharpness based on the standard deviation of a Laplacian convolution, discarding alpha channel if any (experimental)
+ * - `dominant`: Object containing most dominant sRGB colour based on a 4096-bin 3D histogram (experimental)
+ *
+ * @example
+ * const image = sharp(inputJpg);
+ * image
+ *   .stats()
+ *   .then(function(stats) {
+ *      // stats contains the channel-wise statistics array and the isOpaque value
+ *   });
+ *
+ * @example
+ * const { entropy, sharpness, dominant } = await sharp(input).stats();
+ * const { r, g, b } = dominant;
+ *
+ * @param {Function} [callback] - called with the arguments `(err, stats)`
+ * @returns {Promise<Object>}
+ */
+function stats (callback) {
+  if (is.fn(callback)) {
+    if (this._isStreamInput()) {
+      this.on('finish', () => {
+        this._flattenBufferIn();
+        sharp.stats(this.options, callback);
+      });
+    } else {
+      sharp.stats(this.options, callback);
+    }
+    return this;
+  } else {
+    if (this._isStreamInput()) {
+      return new Promise((resolve, reject) => {
+        this.on('finish', function () {
+          this._flattenBufferIn();
+          sharp.stats(this.options, (err, stats) => {
+            if (err) {
+              reject(err);
+            } else {
+              resolve(stats);
+            }
+          });
+        });
+      });
+    } else {
+      return new Promise((resolve, reject) => {
+        sharp.stats(this.options, (err, stats) => {
+          if (err) {
+            reject(err);
+          } else {
+            resolve(stats);
+          }
+        });
+      });
+    }
+  }
+}
+
+/**
+ * Decorate the Sharp prototype with input-related functions.
+ * @private
+ */
+module.exports = function (Sharp) {
+  Object.assign(Sharp.prototype, {
+    // Private
+    _inputOptionsFromObject,
+    _createInputDescriptor,
+    _write,
+    _flattenBufferIn,
+    _isStreamInput,
+    // Public
+    metadata,
+    stats
+  });
+};

lib/is.js

@@ -0,0 +1,129 @@
+'use strict';
+
+/**
+ * Is this value defined and not null?
+ * @private
+ */
+const defined = function (val) {
+  return typeof val !== 'undefined' && val !== null;
+};
+
+/**
+ * Is this value an object?
+ * @private
+ */
+const object = function (val) {
+  return typeof val === 'object';
+};
+
+/**
+ * Is this value a plain object?
+ * @private
+ */
+const plainObject = function (val) {
+  return Object.prototype.toString.call(val) === '[object Object]';
+};
+
+/**
+ * Is this value a function?
+ * @private
+ */
+const fn = function (val) {
+  return typeof val === 'function';
+};
+
+/**
+ * Is this value a boolean?
+ * @private
+ */
+const bool = function (val) {
+  return typeof val === 'boolean';
+};
+
+/**
+ * Is this value a Buffer object?
+ * @private
+ */
+const buffer = function (val) {
+  return val instanceof Buffer;
+};
+
+/**
+ * Is this value a Uint8Array or Uint8ClampedArray object?
+ * @private
+ */
+const uint8Array = function (val) {
+  // allow both since Uint8ClampedArray simply clamps the values between 0-255
+  return val instanceof Uint8Array || val instanceof Uint8ClampedArray;
+};
+
+/**
+ * Is this value a non-empty string?
+ * @private
+ */
+const string = function (val) {
+  return typeof val === 'string' && val.length > 0;
+};
+
+/**
+ * Is this value a real number?
+ * @private
+ */
+const number = function (val) {
+  return typeof val === 'number' && !Number.isNaN(val);
+};
+
+/**
+ * Is this value an integer?
+ * @private
+ */
+const integer = function (val) {
+  return Number.isInteger(val);
+};
+
+/**
+ * Is this value within an inclusive given range?
+ * @private
+ */
+const inRange = function (val, min, max) {
+  return val >= min && val <= max;
+};
+
+/**
+ * Is this value within the elements of an array?
+ * @private
+ */
+const inArray = function (val, list) {
+  return list.includes(val);
+};
+
+/**
+ * Create an Error with a message relating to an invalid parameter.
+ *
+ * @param {string} name - parameter name.
+ * @param {string} expected - description of the type/value/range expected.
+ * @param {*} actual - the value received.
+ * @returns {Error} Containing the formatted message.
+ * @private
+ */
+const invalidParameterError = function (name, expected, actual) {
+  return new Error(
+    `Expected ${expected} for ${name} but received ${actual} of type ${typeof actual}`
+  );
+};
+
+module.exports = {
+  defined: defined,
+  object: object,
+  plainObject: plainObject,
+  fn: fn,
+  bool: bool,
+  buffer: buffer,
+  uint8Array: uint8Array,
+  string: string,
+  number: number,
+  integer: integer,
+  inRange: inRange,
+  inArray: inArray,
+  invalidParameterError: invalidParameterError
+};

lib/libvips.js

@@ -0,0 +1,121 @@
+'use strict';
+
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+const spawnSync = require('child_process').spawnSync;
+const semver = require('semver');
+const platform = require('./platform');
+
+const env = process.env;
+const minimumLibvipsVersionLabelled = env.npm_package_config_libvips || /* istanbul ignore next */
+  require('../package.json').config.libvips;
+const minimumLibvipsVersion = semver.coerce(minimumLibvipsVersionLabelled).version;
+
+const spawnSyncOptions = {
+  encoding: 'utf8',
+  shell: true
+};
+
+const mkdirSync = function (dirPath) {
+  try {
+    fs.mkdirSync(dirPath);
+  } catch (err) {
+    /* istanbul ignore if */
+    if (err.code !== 'EEXIST') {
+      throw err;
+    }
+  }
+};
+
+const cachePath = function () {
+  const npmCachePath = env.npm_config_cache || /* istanbul ignore next */
+    (env.APPDATA ? path.join(env.APPDATA, 'npm-cache') : path.join(os.homedir(), '.npm'));
+  mkdirSync(npmCachePath);
+  const libvipsCachePath = path.join(npmCachePath, '_libvips');
+  mkdirSync(libvipsCachePath);
+  return libvipsCachePath;
+};
+
+const log = function (item) {
+  if (item instanceof Error) {
+    console.error(`sharp: ${item.message}`);
+  } else {
+    console.log(`sharp: ${item}`);
+  }
+};
+
+const isRosetta = function () {
+  /* istanbul ignore next */
+  if (process.platform === 'darwin' && process.arch === 'x64') {
+    const translated = spawnSync('sysctl sysctl.proc_translated', spawnSyncOptions).stdout;
+    return (translated || '').trim() === 'sysctl.proc_translated: 1';
+  }
+  return false;
+};
+
+const globalLibvipsVersion = function () {
+  if (process.platform !== 'win32') {
+    const globalLibvipsVersion = spawnSync(`PKG_CONFIG_PATH="${pkgConfigPath()}" pkg-config --modversion vips-cpp`, spawnSyncOptions).stdout;
+    /* istanbul ignore next */
+    return (globalLibvipsVersion || '').trim();
+  } else {
+    return '';
+  }
+};
+
+const hasVendoredLibvips = function () {
+  const currentPlatformId = platform();
+  const vendorPath = path.join(__dirname, '..', 'vendor', minimumLibvipsVersion);
+  let vendorPlatformId;
+  try {
+    vendorPlatformId = require(path.join(vendorPath, 'platform.json'));
+  } catch (err) {}
+  /* istanbul ignore else */
+  if (vendorPlatformId) {
+    /* istanbul ignore else */
+    if (currentPlatformId === vendorPlatformId) {
+      return true;
+    } else {
+      throw new Error(`'${vendorPlatformId}' binaries cannot be used on the '${currentPlatformId}' platform. Please remove the 'node_modules/sharp' directory and run 'npm install' on the '${currentPlatformId}' platform.`);
+    }
+  } else {
+    return false;
+  }
+};
+
+const pkgConfigPath = function () {
+  if (process.platform !== 'win32') {
+    const brewPkgConfigPath = spawnSync('which brew >/dev/null 2>&1 && eval $(brew --env) && echo $PKG_CONFIG_LIBDIR', spawnSyncOptions).stdout || '';
+    return [brewPkgConfigPath.trim(), env.PKG_CONFIG_PATH, '/usr/local/lib/pkgconfig', '/usr/lib/pkgconfig']
+      .filter(function (p) { return !!p; })
+      .join(':');
+  } else {
+    return '';
+  }
+};
+
+const useGlobalLibvips = function () {
+  if (Boolean(env.SHARP_IGNORE_GLOBAL_LIBVIPS) === true) {
+    return false;
+  }
+  /* istanbul ignore next */
+  if (isRosetta()) {
+    return false;
+  }
+  const globalVipsVersion = globalLibvipsVersion();
+  return !!globalVipsVersion && /* istanbul ignore next */
+    semver.gte(globalVipsVersion, minimumLibvipsVersion);
+};
+
+module.exports = {
+  minimumLibvipsVersion,
+  minimumLibvipsVersionLabelled,
+  cachePath,
+  log,
+  globalLibvipsVersion,
+  hasVendoredLibvips,
+  pkgConfigPath,
+  useGlobalLibvips,
+  mkdirSync
+};

lib/operation.js

@@ -0,0 +1,604 @@
+'use strict';
+
+const color = require('color');
+const is = require('./is');
+
+/**
+ * Rotate the output image by either an explicit angle
+ * or auto-orient based on the EXIF `Orientation` tag.
+ *
+ * If an angle is provided, it is converted to a valid positive degree rotation.
+ * For example, `-450` will produce a 270deg rotation.
+ *
+ * When rotating by an angle other than a multiple of 90,
+ * the background colour can be provided with the `background` option.
+ *
+ * If no angle is provided, it is determined from the EXIF data.
+ * Mirroring is supported and may infer the use of a flip operation.
+ *
+ * The use of `rotate` implies the removal of the EXIF `Orientation` tag, if any.
+ *
+ * Method order is important when both rotating and extracting regions,
+ * for example `rotate(x).extract(y)` will produce a different result to `extract(y).rotate(x)`.
+ *
+ * @example
+ * const pipeline = sharp()
+ *   .rotate()
+ *   .resize(null, 200)
+ *   .toBuffer(function (err, outputBuffer, info) {
+ *     // outputBuffer contains 200px high JPEG image data,
+ *     // auto-rotated using EXIF Orientation tag
+ *     // info.width and info.height contain the dimensions of the resized image
+ *   });
+ * readableStream.pipe(pipeline);
+ *
+ * @param {number} [angle=auto] angle of rotation.
+ * @param {Object} [options] - if present, is an Object with optional attributes.
+ * @param {string|Object} [options.background="#000000"] parsed by the [color](https://www.npmjs.org/package/color) module to extract values for red, green, blue and alpha.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function rotate (angle, options) {
+  if (!is.defined(angle)) {
+    this.options.useExifOrientation = true;
+  } else if (is.integer(angle) && !(angle % 90)) {
+    this.options.angle = angle;
+  } else if (is.number(angle)) {
+    this.options.rotationAngle = angle;
+    if (is.object(options) && options.background) {
+      const backgroundColour = color(options.background);
+      this.options.rotationBackground = [
+        backgroundColour.red(),
+        backgroundColour.green(),
+        backgroundColour.blue(),
+        Math.round(backgroundColour.alpha() * 255)
+      ];
+    }
+  } else {
+    throw is.invalidParameterError('angle', 'numeric', angle);
+  }
+  return this;
+}
+
+/**
+ * Flip the image about the vertical Y axis. This always occurs after rotation, if any.
+ * The use of `flip` implies the removal of the EXIF `Orientation` tag, if any.
+ * @param {Boolean} [flip=true]
+ * @returns {Sharp}
+ */
+function flip (flip) {
+  this.options.flip = is.bool(flip) ? flip : true;
+  return this;
+}
+
+/**
+ * Flop the image about the horizontal X axis. This always occurs after rotation, if any.
+ * The use of `flop` implies the removal of the EXIF `Orientation` tag, if any.
+ * @param {Boolean} [flop=true]
+ * @returns {Sharp}
+ */
+function flop (flop) {
+  this.options.flop = is.bool(flop) ? flop : true;
+  return this;
+}
+
+/**
+ * Perform an affine transform on an image. This operation will always occur after resizing, extraction and rotation, if any.
+ *
+ * You must provide an array of length 4 or a 2x2 affine transformation matrix.
+ * By default, new pixels are filled with a black background. You can provide a background color with the `background` option.
+ * A particular interpolator may also be specified. Set the `interpolator` option to an attribute of the `sharp.interpolator` Object e.g. `sharp.interpolator.nohalo`.
+ *
+ * In the case of a 2x2 matrix, the transform is:
+ * - X = `matrix[0, 0]` \* (x + `idx`) + `matrix[0, 1]` \* (y + `idy`) + `odx`
+ * - Y = `matrix[1, 0]` \* (x + `idx`) + `matrix[1, 1]` \* (y + `idy`) + `ody`
+ *
+ * where:
+ * - x and y are the coordinates in input image.
+ * - X and Y are the coordinates in output image.
+ * - (0,0) is the upper left corner.
+ *
+ * @since 0.27.0
+ *
+ * @example
+ * const pipeline = sharp()
+ *   .affine([[1, 0.3], [0.1, 0.7]], {
+ *      background: 'white',
+ *      interpolate: sharp.interpolators.nohalo
+ *   })
+ *   .toBuffer((err, outputBuffer, info) => {
+ *      // outputBuffer contains the transformed image
+ *      // info.width and info.height contain the new dimensions
+ *   });
+ *
+ * inputStream
+ *   .pipe(pipeline);
+ *
+ * @param {Array<Array<number>>|Array<number>} matrix - affine transformation matrix
+ * @param {Object} [options] - if present, is an Object with optional attributes.
+ * @param {String|Object} [options.background="#000000"] - parsed by the [color](https://www.npmjs.org/package/color) module to extract values for red, green, blue and alpha.
+ * @param {Number} [options.idx=0] - input horizontal offset
+ * @param {Number} [options.idy=0] - input vertical offset
+ * @param {Number} [options.odx=0] - output horizontal offset
+ * @param {Number} [options.ody=0] - output vertical offset
+ * @param {String} [options.interpolator=sharp.interpolators.bicubic] - interpolator
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function affine (matrix, options) {
+  const flatMatrix = [].concat(...matrix);
+  if (flatMatrix.length === 4 && flatMatrix.every(is.number)) {
+    this.options.affineMatrix = flatMatrix;
+  } else {
+    throw is.invalidParameterError('matrix', '1x4 or 2x2 array', matrix);
+  }
+
+  if (is.defined(options)) {
+    if (is.object(options)) {
+      this._setBackgroundColourOption('affineBackground', options.background);
+      if (is.defined(options.idx)) {
+        if (is.number(options.idx)) {
+          this.options.affineIdx = options.idx;
+        } else {
+          throw is.invalidParameterError('options.idx', 'number', options.idx);
+        }
+      }
+      if (is.defined(options.idy)) {
+        if (is.number(options.idy)) {
+          this.options.affineIdy = options.idy;
+        } else {
+          throw is.invalidParameterError('options.idy', 'number', options.idy);
+        }
+      }
+      if (is.defined(options.odx)) {
+        if (is.number(options.odx)) {
+          this.options.affineOdx = options.odx;
+        } else {
+          throw is.invalidParameterError('options.odx', 'number', options.odx);
+        }
+      }
+      if (is.defined(options.ody)) {
+        if (is.number(options.ody)) {
+          this.options.affineOdy = options.ody;
+        } else {
+          throw is.invalidParameterError('options.ody', 'number', options.ody);
+        }
+      }
+      if (is.defined(options.interpolator)) {
+        if (is.inArray(options.interpolator, Object.values(this.constructor.interpolators))) {
+          this.options.affineInterpolator = options.interpolator;
+        } else {
+          throw is.invalidParameterError('options.interpolator', 'valid interpolator name', options.interpolator);
+        }
+      }
+    } else {
+      throw is.invalidParameterError('options', 'object', options);
+    }
+  }
+
+  return this;
+}
+
+/**
+ * Sharpen the image.
+ * When used without parameters, performs a fast, mild sharpen of the output image.
+ * When a `sigma` is provided, performs a slower, more accurate sharpen of the L channel in the LAB colour space.
+ * Separate control over the level of sharpening in "flat" and "jagged" areas is available.
+ *
+ * @param {number} [sigma] - the sigma of the Gaussian mask, where `sigma = 1 + radius / 2`.
+ * @param {number} [flat=1.0] - the level of sharpening to apply to "flat" areas.
+ * @param {number} [jagged=2.0] - the level of sharpening to apply to "jagged" areas.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function sharpen (sigma, flat, jagged) {
+  if (!is.defined(sigma)) {
+    // No arguments: default to mild sharpen
+    this.options.sharpenSigma = -1;
+  } else if (is.bool(sigma)) {
+    // Boolean argument: apply mild sharpen?
+    this.options.sharpenSigma = sigma ? -1 : 0;
+  } else if (is.number(sigma) && is.inRange(sigma, 0.01, 10000)) {
+    // Numeric argument: specific sigma
+    this.options.sharpenSigma = sigma;
+    // Control over flat areas
+    if (is.defined(flat)) {
+      if (is.number(flat) && is.inRange(flat, 0, 10000)) {
+        this.options.sharpenFlat = flat;
+      } else {
+        throw is.invalidParameterError('flat', 'number between 0 and 10000', flat);
+      }
+    }
+    // Control over jagged areas
+    if (is.defined(jagged)) {
+      if (is.number(jagged) && is.inRange(jagged, 0, 10000)) {
+        this.options.sharpenJagged = jagged;
+      } else {
+        throw is.invalidParameterError('jagged', 'number between 0 and 10000', jagged);
+      }
+    }
+  } else {
+    throw is.invalidParameterError('sigma', 'number between 0.01 and 10000', sigma);
+  }
+  return this;
+}
+
+/**
+ * Apply median filter.
+ * When used without parameters the default window is 3x3.
+ * @param {number} [size=3] square mask size: size x size
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function median (size) {
+  if (!is.defined(size)) {
+    // No arguments: default to 3x3
+    this.options.medianSize = 3;
+  } else if (is.integer(size) && is.inRange(size, 1, 1000)) {
+    // Numeric argument: specific sigma
+    this.options.medianSize = size;
+  } else {
+    throw is.invalidParameterError('size', 'integer between 1 and 1000', size);
+  }
+  return this;
+}
+
+/**
+ * Blur the image.
+ * When used without parameters, performs a fast, mild blur of the output image.
+ * When a `sigma` is provided, performs a slower, more accurate Gaussian blur.
+ * @param {number} [sigma] a value between 0.3 and 1000 representing the sigma of the Gaussian mask, where `sigma = 1 + radius / 2`.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function blur (sigma) {
+  if (!is.defined(sigma)) {
+    // No arguments: default to mild blur
+    this.options.blurSigma = -1;
+  } else if (is.bool(sigma)) {
+    // Boolean argument: apply mild blur?
+    this.options.blurSigma = sigma ? -1 : 0;
+  } else if (is.number(sigma) && is.inRange(sigma, 0.3, 1000)) {
+    // Numeric argument: specific sigma
+    this.options.blurSigma = sigma;
+  } else {
+    throw is.invalidParameterError('sigma', 'number between 0.3 and 1000', sigma);
+  }
+  return this;
+}
+
+/**
+ * Merge alpha transparency channel, if any, with a background, then remove the alpha channel.
+ *
+ * @example
+ * await sharp(rgbaInput)
+ *   .flatten('#F0A703')
+ *   .toBuffer();
+ *
+ * @param {Object} [options]
+ * @param {string|Object} [options.background={r: 0, g: 0, b: 0}] - background colour, parsed by the [color](https://www.npmjs.org/package/color) module, defaults to black.
+ * @returns {Sharp}
+ */
+function flatten (options) {
+  this.options.flatten = is.bool(options) ? options : true;
+  if (is.object(options)) {
+    this._setBackgroundColourOption('flattenBackground', options.background);
+  }
+  return this;
+}
+
+/**
+ * Apply a gamma correction by reducing the encoding (darken) pre-resize at a factor of `1/gamma`
+ * then increasing the encoding (brighten) post-resize at a factor of `gamma`.
+ * This can improve the perceived brightness of a resized image in non-linear colour spaces.
+ * JPEG and WebP input images will not take advantage of the shrink-on-load performance optimisation
+ * when applying a gamma correction.
+ *
+ * Supply a second argument to use a different output gamma value, otherwise the first value is used in both cases.
+ *
+ * @param {number} [gamma=2.2] value between 1.0 and 3.0.
+ * @param {number} [gammaOut] value between 1.0 and 3.0. (optional, defaults to same as `gamma`)
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function gamma (gamma, gammaOut) {
+  if (!is.defined(gamma)) {
+    // Default gamma correction of 2.2 (sRGB)
+    this.options.gamma = 2.2;
+  } else if (is.number(gamma) && is.inRange(gamma, 1, 3)) {
+    this.options.gamma = gamma;
+  } else {
+    throw is.invalidParameterError('gamma', 'number between 1.0 and 3.0', gamma);
+  }
+  if (!is.defined(gammaOut)) {
+    // Default gamma correction for output is same as input
+    this.options.gammaOut = this.options.gamma;
+  } else if (is.number(gammaOut) && is.inRange(gammaOut, 1, 3)) {
+    this.options.gammaOut = gammaOut;
+  } else {
+    throw is.invalidParameterError('gammaOut', 'number between 1.0 and 3.0', gammaOut);
+  }
+  return this;
+}
+
+/**
+ * Produce the "negative" of the image.
+ * @param {Boolean} [negate=true]
+ * @returns {Sharp}
+ */
+function negate (negate) {
+  this.options.negate = is.bool(negate) ? negate : true;
+  return this;
+}
+
+/**
+ * Enhance output image contrast by stretching its luminance to cover the full dynamic range.
+ * @param {Boolean} [normalise=true]
+ * @returns {Sharp}
+ */
+function normalise (normalise) {
+  this.options.normalise = is.bool(normalise) ? normalise : true;
+  return this;
+}
+
+/**
+ * Alternative spelling of normalise.
+ * @param {Boolean} [normalize=true]
+ * @returns {Sharp}
+ */
+function normalize (normalize) {
+  return this.normalise(normalize);
+}
+
+/**
+ * Convolve the image with the specified kernel.
+ *
+ * @example
+ * sharp(input)
+ *   .convolve({
+ *     width: 3,
+ *     height: 3,
+ *     kernel: [-1, 0, 1, -2, 0, 2, -1, 0, 1]
+ *   })
+ *   .raw()
+ *   .toBuffer(function(err, data, info) {
+ *     // data contains the raw pixel data representing the convolution
+ *     // of the input image with the horizontal Sobel operator
+ *   });
+ *
+ * @param {Object} kernel
+ * @param {number} kernel.width - width of the kernel in pixels.
+ * @param {number} kernel.height - width of the kernel in pixels.
+ * @param {Array<number>} kernel.kernel - Array of length `width*height` containing the kernel values.
+ * @param {number} [kernel.scale=sum] - the scale of the kernel in pixels.
+ * @param {number} [kernel.offset=0] - the offset of the kernel in pixels.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function convolve (kernel) {
+  if (!is.object(kernel) || !Array.isArray(kernel.kernel) ||
+      !is.integer(kernel.width) || !is.integer(kernel.height) ||
+      !is.inRange(kernel.width, 3, 1001) || !is.inRange(kernel.height, 3, 1001) ||
+      kernel.height * kernel.width !== kernel.kernel.length
+  ) {
+    // must pass in a kernel
+    throw new Error('Invalid convolution kernel');
+  }
+  // Default scale is sum of kernel values
+  if (!is.integer(kernel.scale)) {
+    kernel.scale = kernel.kernel.reduce(function (a, b) {
+      return a + b;
+    }, 0);
+  }
+  // Clip scale to a minimum value of 1
+  if (kernel.scale < 1) {
+    kernel.scale = 1;
+  }
+  if (!is.integer(kernel.offset)) {
+    kernel.offset = 0;
+  }
+  this.options.convKernel = kernel;
+  return this;
+}
+
+/**
+ * Any pixel value greater than or equal to the threshold value will be set to 255, otherwise it will be set to 0.
+ * @param {number} [threshold=128] - a value in the range 0-255 representing the level at which the threshold will be applied.
+ * @param {Object} [options]
+ * @param {Boolean} [options.greyscale=true] - convert to single channel greyscale.
+ * @param {Boolean} [options.grayscale=true] - alternative spelling for greyscale.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function threshold (threshold, options) {
+  if (!is.defined(threshold)) {
+    this.options.threshold = 128;
+  } else if (is.bool(threshold)) {
+    this.options.threshold = threshold ? 128 : 0;
+  } else if (is.integer(threshold) && is.inRange(threshold, 0, 255)) {
+    this.options.threshold = threshold;
+  } else {
+    throw is.invalidParameterError('threshold', 'integer between 0 and 255', threshold);
+  }
+  if (!is.object(options) || options.greyscale === true || options.grayscale === true) {
+    this.options.thresholdGrayscale = true;
+  } else {
+    this.options.thresholdGrayscale = false;
+  }
+  return this;
+}
+
+/**
+ * Perform a bitwise boolean operation with operand image.
+ *
+ * This operation creates an output image where each pixel is the result of
+ * the selected bitwise boolean `operation` between the corresponding pixels of the input images.
+ *
+ * @param {Buffer|string} operand - Buffer containing image data or string containing the path to an image file.
+ * @param {string} operator - one of `and`, `or` or `eor` to perform that bitwise operation, like the C logic operators `&`, `|` and `^` respectively.
+ * @param {Object} [options]
+ * @param {Object} [options.raw] - describes operand when using raw pixel data.
+ * @param {number} [options.raw.width]
+ * @param {number} [options.raw.height]
+ * @param {number} [options.raw.channels]
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function boolean (operand, operator, options) {
+  this.options.boolean = this._createInputDescriptor(operand, options);
+  if (is.string(operator) && is.inArray(operator, ['and', 'or', 'eor'])) {
+    this.options.booleanOp = operator;
+  } else {
+    throw is.invalidParameterError('operator', 'one of: and, or, eor', operator);
+  }
+  return this;
+}
+
+/**
+ * Apply the linear formula a * input + b to the image (levels adjustment)
+ * @param {number} [a=1.0] multiplier
+ * @param {number} [b=0.0] offset
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function linear (a, b) {
+  if (!is.defined(a)) {
+    this.options.linearA = 1.0;
+  } else if (is.number(a)) {
+    this.options.linearA = a;
+  } else {
+    throw is.invalidParameterError('a', 'numeric', a);
+  }
+  if (!is.defined(b)) {
+    this.options.linearB = 0.0;
+  } else if (is.number(b)) {
+    this.options.linearB = b;
+  } else {
+    throw is.invalidParameterError('b', 'numeric', b);
+  }
+  return this;
+}
+
+/**
+ * Recomb the image with the specified matrix.
+ *
+ * @since 0.21.1
+ *
+ * @example
+ * sharp(input)
+ *   .recomb([
+ *    [0.3588, 0.7044, 0.1368],
+ *    [0.2990, 0.5870, 0.1140],
+ *    [0.2392, 0.4696, 0.0912],
+ *   ])
+ *   .raw()
+ *   .toBuffer(function(err, data, info) {
+ *     // data contains the raw pixel data after applying the recomb
+ *     // With this example input, a sepia filter has been applied
+ *   });
+ *
+ * @param {Array<Array<number>>} inputMatrix - 3x3 Recombination matrix
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function recomb (inputMatrix) {
+  if (!Array.isArray(inputMatrix) || inputMatrix.length !== 3 ||
+      inputMatrix[0].length !== 3 ||
+      inputMatrix[1].length !== 3 ||
+      inputMatrix[2].length !== 3
+  ) {
+    // must pass in a kernel
+    throw new Error('Invalid recombination matrix');
+  }
+  this.options.recombMatrix = [
+    inputMatrix[0][0], inputMatrix[0][1], inputMatrix[0][2],
+    inputMatrix[1][0], inputMatrix[1][1], inputMatrix[1][2],
+    inputMatrix[2][0], inputMatrix[2][1], inputMatrix[2][2]
+  ].map(Number);
+  return this;
+}
+
+/**
+ * Transforms the image using brightness, saturation and hue rotation.
+ *
+ * @since 0.22.1
+ *
+ * @example
+ * sharp(input)
+ *   .modulate({
+ *     brightness: 2 // increase lightness by a factor of 2
+ *   });
+ *
+ * sharp(input)
+ *   .modulate({
+ *     hue: 180 // hue-rotate by 180 degrees
+ *   });
+ *
+ * // decreate brightness and saturation while also hue-rotating by 90 degrees
+ * sharp(input)
+ *   .modulate({
+ *     brightness: 0.5,
+ *     saturation: 0.5,
+ *     hue: 90
+ *   });
+ *
+ * @param {Object} [options]
+ * @param {number} [options.brightness] Brightness multiplier
+ * @param {number} [options.saturation] Saturation multiplier
+ * @param {number} [options.hue] Degrees for hue rotation
+ * @returns {Sharp}
+ */
+function modulate (options) {
+  if (!is.plainObject(options)) {
+    throw is.invalidParameterError('options', 'plain object', options);
+  }
+  if ('brightness' in options) {
+    if (is.number(options.brightness) && options.brightness >= 0) {
+      this.options.brightness = options.brightness;
+    } else {
+      throw is.invalidParameterError('brightness', 'number above zero', options.brightness);
+    }
+  }
+  if ('saturation' in options) {
+    if (is.number(options.saturation) && options.saturation >= 0) {
+      this.options.saturation = options.saturation;
+    } else {
+      throw is.invalidParameterError('saturation', 'number above zero', options.saturation);
+    }
+  }
+  if ('hue' in options) {
+    if (is.integer(options.hue)) {
+      this.options.hue = options.hue % 360;
+    } else {
+      throw is.invalidParameterError('hue', 'number', options.hue);
+    }
+  }
+  return this;
+}
+
+/**
+ * Decorate the Sharp prototype with operation-related functions.
+ * @private
+ */
+module.exports = function (Sharp) {
+  Object.assign(Sharp.prototype, {
+    rotate,
+    flip,
+    flop,
+    affine,
+    sharpen,
+    median,
+    blur,
+    flatten,
+    gamma,
+    negate,
+    normalise,
+    normalize,
+    convolve,
+    threshold,
+    boolean,
+    linear,
+    recomb,
+    modulate
+  });
+};

lib/output.js

@@ -0,0 +1,983 @@
+'use strict';
+
+const is = require('./is');
+const sharp = require('../build/Release/sharp.node');
+
+const formats = new Map([
+  ['heic', 'heif'],
+  ['heif', 'heif'],
+  ['avif', 'avif'],
+  ['jpeg', 'jpeg'],
+  ['jpg', 'jpeg'],
+  ['png', 'png'],
+  ['raw', 'raw'],
+  ['tiff', 'tiff'],
+  ['webp', 'webp'],
+  ['gif', 'gif']
+]);
+
+const errMagickSave = new Error('GIF output requires libvips with support for ImageMagick');
+
+/**
+ * Write output image data to a file.
+ *
+ * If an explicit output format is not selected, it will be inferred from the extension,
+ * with JPEG, PNG, WebP, AVIF, TIFF, DZI, and libvips' V format supported.
+ * Note that raw pixel data is only supported for buffer output.
+ *
+ * By default all metadata will be removed, which includes EXIF-based orientation.
+ * See {@link withMetadata} for control over this.
+ *
+ * A `Promise` is returned when `callback` is not provided.
+ *
+ * @example
+ * sharp(input)
+ *   .toFile('output.png', (err, info) => { ... });
+ *
+ * @example
+ * sharp(input)
+ *   .toFile('output.png')
+ *   .then(info => { ... })
+ *   .catch(err => { ... });
+ *
+ * @param {string} fileOut - the path to write the image data to.
+ * @param {Function} [callback] - called on completion with two arguments `(err, info)`.
+ * `info` contains the output image `format`, `size` (bytes), `width`, `height`,
+ * `channels` and `premultiplied` (indicating if premultiplication was used).
+ * When using a crop strategy also contains `cropOffsetLeft` and `cropOffsetTop`.
+ * @returns {Promise<Object>} - when no callback is provided
+ * @throws {Error} Invalid parameters
+ */
+function toFile (fileOut, callback) {
+  let err;
+  if (!is.string(fileOut)) {
+    err = new Error('Missing output file path');
+  } else if (this.options.input.file === fileOut) {
+    err = new Error('Cannot use same file for input and output');
+  } else if (this.options.formatOut === 'input' && fileOut.toLowerCase().endsWith('.gif') && !this.constructor.format.magick.output.file) {
+    err = errMagickSave;
+  }
+  if (err) {
+    if (is.fn(callback)) {
+      callback(err);
+    } else {
+      return Promise.reject(err);
+    }
+  } else {
+    this.options.fileOut = fileOut;
+    return this._pipeline(callback);
+  }
+  return this;
+}
+
+/**
+ * Write output to a Buffer.
+ * JPEG, PNG, WebP, AVIF, TIFF and raw pixel data output are supported.
+ *
+ * If no explicit format is set, the output format will match the input image, except GIF and SVG input which become PNG output.
+ *
+ * By default all metadata will be removed, which includes EXIF-based orientation.
+ * See {@link withMetadata} for control over this.
+ *
+ * `callback`, if present, gets three arguments `(err, data, info)` where:
+ * - `err` is an error, if any.
+ * - `data` is the output image data.
+ * - `info` contains the output image `format`, `size` (bytes), `width`, `height`,
+ * `channels` and `premultiplied` (indicating if premultiplication was used).
+ * When using a crop strategy also contains `cropOffsetLeft` and `cropOffsetTop`.
+ *
+ * A `Promise` is returned when `callback` is not provided.
+ *
+ * @example
+ * sharp(input)
+ *   .toBuffer((err, data, info) => { ... });
+ *
+ * @example
+ * sharp(input)
+ *   .toBuffer()
+ *   .then(data => { ... })
+ *   .catch(err => { ... });
+ *
+ * @example
+ * sharp(input)
+ *   .toBuffer({ resolveWithObject: true })
+ *   .then(({ data, info }) => { ... })
+ *   .catch(err => { ... });
+ *
+ * @example
+ * const { data, info } = await sharp('my-image.jpg')
+ *   // output the raw pixels
+ *   .raw()
+ *   .toBuffer({ resolveWithObject: true });
+ *
+ * // create a more type safe way to work with the raw pixel data
+ * // this will not copy the data, instead it will change `data`s underlying ArrayBuffer
+ * // so `data` and `pixelArray` point to the same memory location
+ * const pixelArray = new Uint8ClampedArray(data.buffer);
+ *
+ * // When you are done changing the pixelArray, sharp takes the `pixelArray` as an input
+ * const { width, height, channels } = info;
+ * await sharp(pixelArray, { raw: { width, height, channels } })
+ *   .toFile('my-changed-image.jpg');
+ *
+ * @param {Object} [options]
+ * @param {boolean} [options.resolveWithObject] Resolve the Promise with an Object containing `data` and `info` properties instead of resolving only with `data`.
+ * @param {Function} [callback]
+ * @returns {Promise<Buffer>} - when no callback is provided
+ */
+function toBuffer (options, callback) {
+  if (is.object(options)) {
+    this._setBooleanOption('resolveWithObject', options.resolveWithObject);
+  } else if (this.options.resolveWithObject) {
+    this.options.resolveWithObject = false;
+  }
+  return this._pipeline(is.fn(options) ? options : callback);
+}
+
+/**
+ * Include all metadata (EXIF, XMP, IPTC) from the input image in the output image.
+ * This will also convert to and add a web-friendly sRGB ICC profile unless a custom
+ * output profile is provided.
+ *
+ * The default behaviour, when `withMetadata` is not used, is to convert to the device-independent
+ * sRGB colour space and strip all metadata, including the removal of any ICC profile.
+ *
+ * @example
+ * sharp('input.jpg')
+ *   .withMetadata()
+ *   .toFile('output-with-metadata.jpg')
+ *   .then(info => { ... });
+ *
+ * @param {Object} [options]
+ * @param {number} [options.orientation] value between 1 and 8, used to update the EXIF `Orientation` tag.
+ * @param {string} [options.icc] filesystem path to output ICC profile, defaults to sRGB.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function withMetadata (options) {
+  this.options.withMetadata = is.bool(options) ? options : true;
+  if (is.object(options)) {
+    if (is.defined(options.orientation)) {
+      if (is.integer(options.orientation) && is.inRange(options.orientation, 1, 8)) {
+        this.options.withMetadataOrientation = options.orientation;
+      } else {
+        throw is.invalidParameterError('orientation', 'integer between 1 and 8', options.orientation);
+      }
+    }
+    if (is.defined(options.icc)) {
+      if (is.string(options.icc)) {
+        this.options.withMetadataIcc = options.icc;
+      } else {
+        throw is.invalidParameterError('icc', 'string filesystem path to ICC profile', options.icc);
+      }
+    }
+  }
+  return this;
+}
+
+/**
+ * Force output to a given format.
+ *
+ * @example
+ * // Convert any input to PNG output
+ * const data = await sharp(input)
+ *   .toFormat('png')
+ *   .toBuffer();
+ *
+ * @param {(string|Object)} format - as a string or an Object with an 'id' attribute
+ * @param {Object} options - output options
+ * @returns {Sharp}
+ * @throws {Error} unsupported format or options
+ */
+function toFormat (format, options) {
+  const actualFormat = formats.get((is.object(format) && is.string(format.id) ? format.id : format).toLowerCase());
+  if (!actualFormat) {
+    throw is.invalidParameterError('format', `one of: ${[...formats.keys()].join(', ')}`, format);
+  }
+  return this[actualFormat](options);
+}
+
+/**
+ * Use these JPEG options for output image.
+ *
+ * @example
+ * // Convert any input to very high quality JPEG output
+ * const data = await sharp(input)
+ *   .jpeg({
+ *     quality: 100,
+ *     chromaSubsampling: '4:4:4'
+ *   })
+ *   .toBuffer();
+ *
+ * @example
+ * // Use mozjpeg to reduce output JPEG file size (slower)
+ * const data = await sharp(input)
+ *   .jpeg({ mozjpeg: true })
+ *   .toBuffer();
+ *
+ * @param {Object} [options] - output options
+ * @param {number} [options.quality=80] - quality, integer 1-100
+ * @param {boolean} [options.progressive=false] - use progressive (interlace) scan
+ * @param {string} [options.chromaSubsampling='4:2:0'] - set to '4:4:4' to prevent chroma subsampling otherwise defaults to '4:2:0' chroma subsampling
+ * @param {boolean} [options.optimiseCoding=true] - optimise Huffman coding tables
+ * @param {boolean} [options.optimizeCoding=true] - alternative spelling of optimiseCoding
+ * @param {boolean} [options.mozjpeg=false] - use mozjpeg defaults, equivalent to `{ trellisQuantisation: true, overshootDeringing: true, optimiseScans: true, quantisationTable: 3 }`
+ * @param {boolean} [options.trellisQuantisation=false] - apply trellis quantisation
+ * @param {boolean} [options.overshootDeringing=false] - apply overshoot deringing
+ * @param {boolean} [options.optimiseScans=false] - optimise progressive scans, forces progressive
+ * @param {boolean} [options.optimizeScans=false] - alternative spelling of optimiseScans
+ * @param {number} [options.quantisationTable=0] - quantization table to use, integer 0-8
+ * @param {number} [options.quantizationTable=0] - alternative spelling of quantisationTable
+ * @param {boolean} [options.force=true] - force JPEG output, otherwise attempt to use input format
+ * @returns {Sharp}
+ * @throws {Error} Invalid options
+ */
+function jpeg (options) {
+  if (is.object(options)) {
+    if (is.defined(options.quality)) {
+      if (is.integer(options.quality) && is.inRange(options.quality, 1, 100)) {
+        this.options.jpegQuality = options.quality;
+      } else {
+        throw is.invalidParameterError('quality', 'integer between 1 and 100', options.quality);
+      }
+    }
+    if (is.defined(options.progressive)) {
+      this._setBooleanOption('jpegProgressive', options.progressive);
+    }
+    if (is.defined(options.chromaSubsampling)) {
+      if (is.string(options.chromaSubsampling) && is.inArray(options.chromaSubsampling, ['4:2:0', '4:4:4'])) {
+        this.options.jpegChromaSubsampling = options.chromaSubsampling;
+      } else {
+        throw is.invalidParameterError('chromaSubsampling', 'one of: 4:2:0, 4:4:4', options.chromaSubsampling);
+      }
+    }
+    const optimiseCoding = is.bool(options.optimizeCoding) ? options.optimizeCoding : options.optimiseCoding;
+    if (is.defined(optimiseCoding)) {
+      this._setBooleanOption('jpegOptimiseCoding', optimiseCoding);
+    }
+    if (is.defined(options.mozjpeg)) {
+      if (is.bool(options.mozjpeg)) {
+        if (options.mozjpeg) {
+          this.options.jpegTrellisQuantisation = true;
+          this.options.jpegOvershootDeringing = true;
+          this.options.jpegOptimiseScans = true;
+          this.options.jpegProgressive = true;
+          this.options.jpegQuantisationTable = 3;
+        }
+      } else {
+        throw is.invalidParameterError('mozjpeg', 'boolean', options.mozjpeg);
+      }
+    }
+    const trellisQuantisation = is.bool(options.trellisQuantization) ? options.trellisQuantization : options.trellisQuantisation;
+    if (is.defined(trellisQuantisation)) {
+      this._setBooleanOption('jpegTrellisQuantisation', trellisQuantisation);
+    }
+    if (is.defined(options.overshootDeringing)) {
+      this._setBooleanOption('jpegOvershootDeringing', options.overshootDeringing);
+    }
+    const optimiseScans = is.bool(options.optimizeScans) ? options.optimizeScans : options.optimiseScans;
+    if (is.defined(optimiseScans)) {
+      this._setBooleanOption('jpegOptimiseScans', optimiseScans);
+      if (optimiseScans) {
+        this.options.jpegProgressive = true;
+      }
+    }
+    const quantisationTable = is.number(options.quantizationTable) ? options.quantizationTable : options.quantisationTable;
+    if (is.defined(quantisationTable)) {
+      if (is.integer(quantisationTable) && is.inRange(quantisationTable, 0, 8)) {
+        this.options.jpegQuantisationTable = quantisationTable;
+      } else {
+        throw is.invalidParameterError('quantisationTable', 'integer between 0 and 8', quantisationTable);
+      }
+    }
+  }
+  return this._updateFormatOut('jpeg', options);
+}
+
+/**
+ * Use these PNG options for output image.
+ *
+ * By default, PNG output is full colour at 8 or 16 bits per pixel.
+ * Indexed PNG input at 1, 2 or 4 bits per pixel is converted to 8 bits per pixel.
+ * Set `palette` to `true` for slower, indexed PNG output.
+ *
+ * @example
+ * // Convert any input to full colour PNG output
+ * const data = await sharp(input)
+ *   .png()
+ *   .toBuffer();
+ *
+ * @example
+ * // Convert any input to indexed PNG output (slower)
+ * const data = await sharp(input)
+ *   .png({ palette: true })
+ *   .toBuffer();
+ *
+ * @param {Object} [options]
+ * @param {boolean} [options.progressive=false] - use progressive (interlace) scan
+ * @param {number} [options.compressionLevel=6] - zlib compression level, 0 (fastest, largest) to 9 (slowest, smallest)
+ * @param {boolean} [options.adaptiveFiltering=false] - use adaptive row filtering
+ * @param {boolean} [options.palette=false] - quantise to a palette-based image with alpha transparency support
+ * @param {number} [options.quality=100] - use the lowest number of colours needed to achieve given quality, sets `palette` to `true`
+ * @param {number} [options.colours=256] - maximum number of palette entries, sets `palette` to `true`
+ * @param {number} [options.colors=256] - alternative spelling of `options.colours`, sets `palette` to `true`
+ * @param {number} [options.dither=1.0] - level of Floyd-Steinberg error diffusion, sets `palette` to `true`
+ * @param {boolean} [options.force=true] - force PNG output, otherwise attempt to use input format
+ * @returns {Sharp}
+ * @throws {Error} Invalid options
+ */
+function png (options) {
+  if (is.object(options)) {
+    if (is.defined(options.progressive)) {
+      this._setBooleanOption('pngProgressive', options.progressive);
+    }
+    if (is.defined(options.compressionLevel)) {
+      if (is.integer(options.compressionLevel) && is.inRange(options.compressionLevel, 0, 9)) {
+        this.options.pngCompressionLevel = options.compressionLevel;
+      } else {
+        throw is.invalidParameterError('compressionLevel', 'integer between 0 and 9', options.compressionLevel);
+      }
+    }
+    if (is.defined(options.adaptiveFiltering)) {
+      this._setBooleanOption('pngAdaptiveFiltering', options.adaptiveFiltering);
+    }
+    if (is.defined(options.palette)) {
+      this._setBooleanOption('pngPalette', options.palette);
+    } else if (is.defined(options.quality) || is.defined(options.colours || options.colors) || is.defined(options.dither)) {
+      this._setBooleanOption('pngPalette', true);
+    }
+    if (this.options.pngPalette) {
+      if (is.defined(options.quality)) {
+        if (is.integer(options.quality) && is.inRange(options.quality, 0, 100)) {
+          this.options.pngQuality = options.quality;
+        } else {
+          throw is.invalidParameterError('quality', 'integer between 0 and 100', options.quality);
+        }
+      }
+      const colours = options.colours || options.colors;
+      if (is.defined(colours)) {
+        if (is.integer(colours) && is.inRange(colours, 2, 256)) {
+          this.options.pngColours = colours;
+        } else {
+          throw is.invalidParameterError('colours', 'integer between 2 and 256', colours);
+        }
+      }
+      if (is.defined(options.dither)) {
+        if (is.number(options.dither) && is.inRange(options.dither, 0, 1)) {
+          this.options.pngDither = options.dither;
+        } else {
+          throw is.invalidParameterError('dither', 'number between 0.0 and 1.0', options.dither);
+        }
+      }
+    }
+  }
+  return this._updateFormatOut('png', options);
+}
+
+/**
+ * Use these WebP options for output image.
+ *
+ * @example
+ * // Convert any input to lossless WebP output
+ * const data = await sharp(input)
+ *   .webp({ lossless: true })
+ *   .toBuffer();
+ *
+ * @param {Object} [options] - output options
+ * @param {number} [options.quality=80] - quality, integer 1-100
+ * @param {number} [options.alphaQuality=100] - quality of alpha layer, integer 0-100
+ * @param {boolean} [options.lossless=false] - use lossless compression mode
+ * @param {boolean} [options.nearLossless=false] - use near_lossless compression mode
+ * @param {boolean} [options.smartSubsample=false] - use high quality chroma subsampling
+ * @param {number} [options.reductionEffort=4] - level of CPU effort to reduce file size, integer 0-6
+ * @param {number} [options.pageHeight] - page height for animated output
+ * @param {number} [options.loop=0] - number of animation iterations, use 0 for infinite animation
+ * @param {number[]} [options.delay] - list of delays between animation frames (in milliseconds)
+ * @param {boolean} [options.force=true] - force WebP output, otherwise attempt to use input format
+ * @returns {Sharp}
+ * @throws {Error} Invalid options
+ */
+function webp (options) {
+  if (is.object(options) && is.defined(options.quality)) {
+    if (is.integer(options.quality) && is.inRange(options.quality, 1, 100)) {
+      this.options.webpQuality = options.quality;
+    } else {
+      throw is.invalidParameterError('quality', 'integer between 1 and 100', options.quality);
+    }
+  }
+  if (is.object(options) && is.defined(options.alphaQuality)) {
+    if (is.integer(options.alphaQuality) && is.inRange(options.alphaQuality, 0, 100)) {
+      this.options.webpAlphaQuality = options.alphaQuality;
+    } else {
+      throw is.invalidParameterError('alphaQuality', 'integer between 0 and 100', options.alphaQuality);
+    }
+  }
+  if (is.object(options) && is.defined(options.lossless)) {
+    this._setBooleanOption('webpLossless', options.lossless);
+  }
+  if (is.object(options) && is.defined(options.nearLossless)) {
+    this._setBooleanOption('webpNearLossless', options.nearLossless);
+  }
+  if (is.object(options) && is.defined(options.smartSubsample)) {
+    this._setBooleanOption('webpSmartSubsample', options.smartSubsample);
+  }
+  if (is.object(options) && is.defined(options.reductionEffort)) {
+    if (is.integer(options.reductionEffort) && is.inRange(options.reductionEffort, 0, 6)) {
+      this.options.webpReductionEffort = options.reductionEffort;
+    } else {
+      throw is.invalidParameterError('reductionEffort', 'integer between 0 and 6', options.reductionEffort);
+    }
+  }
+
+  trySetAnimationOptions(options, this.options);
+  return this._updateFormatOut('webp', options);
+}
+
+/**
+ * Use these GIF options for output image.
+ *
+ * Requires libvips compiled with support for ImageMagick or GraphicsMagick.
+ * The prebuilt binaries do not include this - see
+ * {@link https://sharp.pixelplumbing.com/install#custom-libvips installing a custom libvips}.
+ *
+ * @param {Object} [options] - output options
+ * @param {number} [options.pageHeight] - page height for animated output
+ * @param {number} [options.loop=0] - number of animation iterations, use 0 for infinite animation
+ * @param {number[]} [options.delay] - list of delays between animation frames (in milliseconds)
+ * @param {boolean} [options.force=true] - force GIF output, otherwise attempt to use input format
+ * @returns {Sharp}
+ * @throws {Error} Invalid options
+ */
+/* istanbul ignore next */
+function gif (options) {
+  if (!this.constructor.format.magick.output.buffer) {
+    throw errMagickSave;
+  }
+  trySetAnimationOptions(options, this.options);
+  return this._updateFormatOut('gif', options);
+}
+
+/**
+ * Set animation options if available.
+ * @private
+ *
+ * @param {Object} [source] - output options
+ * @param {number} [source.pageHeight] - page height for animated output
+ * @param {number} [source.loop=0] - number of animation iterations, use 0 for infinite animation
+ * @param {number[]} [source.delay] - list of delays between animation frames (in milliseconds)
+ * @param {Object} [target] - target object for valid options
+ * @throws {Error} Invalid options
+ */
+function trySetAnimationOptions (source, target) {
+  if (is.object(source) && is.defined(source.pageHeight)) {
+    if (is.integer(source.pageHeight) && source.pageHeight > 0) {
+      target.pageHeight = source.pageHeight;
+    } else {
+      throw is.invalidParameterError('pageHeight', 'integer larger than 0', source.pageHeight);
+    }
+  }
+  if (is.object(source) && is.defined(source.loop)) {
+    if (is.integer(source.loop) && is.inRange(source.loop, 0, 65535)) {
+      target.loop = source.loop;
+    } else {
+      throw is.invalidParameterError('loop', 'integer between 0 and 65535', source.loop);
+    }
+  }
+  if (is.object(source) && is.defined(source.delay)) {
+    if (
+      Array.isArray(source.delay) &&
+      source.delay.every(is.integer) &&
+      source.delay.every(v => is.inRange(v, 0, 65535))) {
+      target.delay = source.delay;
+    } else {
+      throw is.invalidParameterError('delay', 'array of integers between 0 and 65535', source.delay);
+    }
+  }
+}
+
+/**
+ * Use these TIFF options for output image.
+ *
+ * @example
+ * // Convert SVG input to LZW-compressed, 1 bit per pixel TIFF output
+ * sharp('input.svg')
+ *   .tiff({
+ *     compression: 'lzw',
+ *     bitdepth: 1
+ *   })
+ *   .toFile('1-bpp-output.tiff')
+ *   .then(info => { ... });
+ *
+ * @param {Object} [options] - output options
+ * @param {number} [options.quality=80] - quality, integer 1-100
+ * @param {boolean} [options.force=true] - force TIFF output, otherwise attempt to use input format
+ * @param {string} [options.compression='jpeg'] - compression options: lzw, deflate, jpeg, ccittfax4
+ * @param {string} [options.predictor='horizontal'] - compression predictor options: none, horizontal, float
+ * @param {boolean} [options.pyramid=false] - write an image pyramid
+ * @param {boolean} [options.tile=false] - write a tiled tiff
+ * @param {number} [options.tileWidth=256] - horizontal tile size
+ * @param {number} [options.tileHeight=256] - vertical tile size
+ * @param {number} [options.xres=1.0] - horizontal resolution in pixels/mm
+ * @param {number} [options.yres=1.0] - vertical resolution in pixels/mm
+ * @param {number} [options.bitdepth=8] - reduce bitdepth to 1, 2 or 4 bit
+ * @returns {Sharp}
+ * @throws {Error} Invalid options
+ */
+function tiff (options) {
+  if (is.object(options)) {
+    if (is.defined(options.quality)) {
+      if (is.integer(options.quality) && is.inRange(options.quality, 1, 100)) {
+        this.options.tiffQuality = options.quality;
+      } else {
+        throw is.invalidParameterError('quality', 'integer between 1 and 100', options.quality);
+      }
+    }
+    if (is.defined(options.bitdepth)) {
+      if (is.integer(options.bitdepth) && is.inArray(options.bitdepth, [1, 2, 4, 8])) {
+        this.options.tiffBitdepth = options.bitdepth;
+      } else {
+        throw is.invalidParameterError('bitdepth', '1, 2, 4 or 8', options.bitdepth);
+      }
+    }
+    // tiling
+    if (is.defined(options.tile)) {
+      this._setBooleanOption('tiffTile', options.tile);
+    }
+    if (is.defined(options.tileWidth)) {
+      if (is.integer(options.tileWidth) && options.tileWidth > 0) {
+        this.options.tiffTileWidth = options.tileWidth;
+      } else {
+        throw is.invalidParameterError('tileWidth', 'integer greater than zero', options.tileWidth);
+      }
+    }
+    if (is.defined(options.tileHeight)) {
+      if (is.integer(options.tileHeight) && options.tileHeight > 0) {
+        this.options.tiffTileHeight = options.tileHeight;
+      } else {
+        throw is.invalidParameterError('tileHeight', 'integer greater than zero', options.tileHeight);
+      }
+    }
+    // pyramid
+    if (is.defined(options.pyramid)) {
+      this._setBooleanOption('tiffPyramid', options.pyramid);
+    }
+    // resolution
+    if (is.defined(options.xres)) {
+      if (is.number(options.xres) && options.xres > 0) {
+        this.options.tiffXres = options.xres;
+      } else {
+        throw is.invalidParameterError('xres', 'number greater than zero', options.xres);
+      }
+    }
+    if (is.defined(options.yres)) {
+      if (is.number(options.yres) && options.yres > 0) {
+        this.options.tiffYres = options.yres;
+      } else {
+        throw is.invalidParameterError('yres', 'number greater than zero', options.yres);
+      }
+    }
+    // compression
+    if (is.defined(options.compression)) {
+      if (is.string(options.compression) && is.inArray(options.compression, ['lzw', 'deflate', 'jpeg', 'ccittfax4', 'none'])) {
+        this.options.tiffCompression = options.compression;
+      } else {
+        throw is.invalidParameterError('compression', 'one of: lzw, deflate, jpeg, ccittfax4, none', options.compression);
+      }
+    }
+    // predictor
+    if (is.defined(options.predictor)) {
+      if (is.string(options.predictor) && is.inArray(options.predictor, ['none', 'horizontal', 'float'])) {
+        this.options.tiffPredictor = options.predictor;
+      } else {
+        throw is.invalidParameterError('predictor', 'one of: none, horizontal, float', options.predictor);
+      }
+    }
+  }
+  return this._updateFormatOut('tiff', options);
+}
+
+/**
+ * Use these AVIF options for output image.
+ *
+ * Whilst it is possible to create AVIF images smaller than 16x16 pixels,
+ * most web browsers do not display these properly.
+ *
+ * @since 0.27.0
+ *
+ * @param {Object} [options] - output options
+ * @param {number} [options.quality=50] - quality, integer 1-100
+ * @param {boolean} [options.lossless=false] - use lossless compression
+ * @param {number} [options.speed=5] - CPU effort vs file size, 0 (slowest/smallest) to 8 (fastest/largest)
+ * @param {string} [options.chromaSubsampling='4:2:0'] - set to '4:4:4' to prevent chroma subsampling otherwise defaults to '4:2:0' chroma subsampling, requires libvips v8.11.0
+ * @returns {Sharp}
+ * @throws {Error} Invalid options
+ */
+function avif (options) {
+  return this.heif({ ...options, compression: 'av1' });
+}
+
+/**
+ * Use these HEIF options for output image.
+ *
+ * Support for patent-encumbered HEIC images requires the use of a
+ * globally-installed libvips compiled with support for libheif, libde265 and x265.
+ *
+ * @since 0.23.0
+ *
+ * @param {Object} [options] - output options
+ * @param {number} [options.quality=50] - quality, integer 1-100
+ * @param {string} [options.compression='av1'] - compression format: av1, hevc
+ * @param {boolean} [options.lossless=false] - use lossless compression
+ * @param {number} [options.speed=5] - CPU effort vs file size, 0 (slowest/smallest) to 8 (fastest/largest)
+ * @param {string} [options.chromaSubsampling='4:2:0'] - set to '4:4:4' to prevent chroma subsampling otherwise defaults to '4:2:0' chroma subsampling, requires libvips v8.11.0
+ * @returns {Sharp}
+ * @throws {Error} Invalid options
+ */
+function heif (options) {
+  if (is.object(options)) {
+    if (is.defined(options.quality)) {
+      if (is.integer(options.quality) && is.inRange(options.quality, 1, 100)) {
+        this.options.heifQuality = options.quality;
+      } else {
+        throw is.invalidParameterError('quality', 'integer between 1 and 100', options.quality);
+      }
+    }
+    if (is.defined(options.lossless)) {
+      if (is.bool(options.lossless)) {
+        this.options.heifLossless = options.lossless;
+      } else {
+        throw is.invalidParameterError('lossless', 'boolean', options.lossless);
+      }
+    }
+    if (is.defined(options.compression)) {
+      if (is.string(options.compression) && is.inArray(options.compression, ['av1', 'hevc'])) {
+        this.options.heifCompression = options.compression;
+      } else {
+        throw is.invalidParameterError('compression', 'one of: av1, hevc', options.compression);
+      }
+    }
+    if (is.defined(options.speed)) {
+      if (is.integer(options.speed) && is.inRange(options.speed, 0, 8)) {
+        this.options.heifSpeed = options.speed;
+      } else {
+        throw is.invalidParameterError('speed', 'integer between 0 and 8', options.speed);
+      }
+    }
+    if (is.defined(options.chromaSubsampling)) {
+      if (is.string(options.chromaSubsampling) && is.inArray(options.chromaSubsampling, ['4:2:0', '4:4:4'])) {
+        this.options.heifChromaSubsampling = options.chromaSubsampling;
+      } else {
+        throw is.invalidParameterError('chromaSubsampling', 'one of: 4:2:0, 4:4:4', options.chromaSubsampling);
+      }
+    }
+  }
+  return this._updateFormatOut('heif', options);
+}
+
+/**
+ * Force output to be raw, uncompressed, 8-bit unsigned integer (unit8) pixel data.
+ * Pixel ordering is left-to-right, top-to-bottom, without padding.
+ * Channel ordering will be RGB or RGBA for non-greyscale colourspaces.
+ *
+ * @example
+ * // Extract raw RGB pixel data from JPEG input
+ * const { data, info } = await sharp('input.jpg')
+ *   .raw()
+ *   .toBuffer({ resolveWithObject: true });
+ *
+ * @example
+ * // Extract alpha channel as raw pixel data from PNG input
+ * const data = await sharp('input.png')
+ *   .ensureAlpha()
+ *   .extractChannel(3)
+ *   .toColourspace('b-w')
+ *   .raw()
+ *   .toBuffer();
+ *
+ * @returns {Sharp}
+ */
+function raw () {
+  return this._updateFormatOut('raw');
+}
+
+/**
+ * Use tile-based deep zoom (image pyramid) output.
+ * Set the format and options for tile images via the `toFormat`, `jpeg`, `png` or `webp` functions.
+ * Use a `.zip` or `.szi` file extension with `toFile` to write to a compressed archive file format.
+ *
+ * Warning: multiple sharp instances concurrently producing tile output can expose a possible race condition in some versions of libgsf.
+ *
+ * @example
+ *  sharp('input.tiff')
+ *   .png()
+ *   .tile({
+ *     size: 512
+ *   })
+ *   .toFile('output.dz', function(err, info) {
+ *     // output.dzi is the Deep Zoom XML definition
+ *     // output_files contains 512x512 tiles grouped by zoom level
+ *   });
+ *
+ * @param {Object} [options]
+ * @param {number} [options.size=256] tile size in pixels, a value between 1 and 8192.
+ * @param {number} [options.overlap=0] tile overlap in pixels, a value between 0 and 8192.
+ * @param {number} [options.angle=0] tile angle of rotation, must be a multiple of 90.
+ * @param {string|Object} [options.background={r: 255, g: 255, b: 255, alpha: 1}] - background colour, parsed by the [color](https://www.npmjs.org/package/color) module, defaults to white without transparency.
+ * @param {string} [options.depth] how deep to make the pyramid, possible values are `onepixel`, `onetile` or `one`, default based on layout.
+ * @param {number} [options.skipBlanks=-1] threshold to skip tile generation, a value 0 - 255 for 8-bit images or 0 - 65535 for 16-bit images
+ * @param {string} [options.container='fs'] tile container, with value `fs` (filesystem) or `zip` (compressed file).
+ * @param {string} [options.layout='dz'] filesystem layout, possible values are `dz`, `iiif`, `zoomify` or `google`.
+ * @param {boolean} [options.centre=false] centre image in tile.
+ * @param {boolean} [options.center=false] alternative spelling of centre.
+ * @param {string} [options.id='https://example.com/iiif'] when `layout` is `iiif`, sets the `@id` attribute of `info.json`
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function tile (options) {
+  if (is.object(options)) {
+    // Size of square tiles, in pixels
+    if (is.defined(options.size)) {
+      if (is.integer(options.size) && is.inRange(options.size, 1, 8192)) {
+        this.options.tileSize = options.size;
+      } else {
+        throw is.invalidParameterError('size', 'integer between 1 and 8192', options.size);
+      }
+    }
+    // Overlap of tiles, in pixels
+    if (is.defined(options.overlap)) {
+      if (is.integer(options.overlap) && is.inRange(options.overlap, 0, 8192)) {
+        if (options.overlap > this.options.tileSize) {
+          throw is.invalidParameterError('overlap', `<= size (${this.options.tileSize})`, options.overlap);
+        }
+        this.options.tileOverlap = options.overlap;
+      } else {
+        throw is.invalidParameterError('overlap', 'integer between 0 and 8192', options.overlap);
+      }
+    }
+    // Container
+    if (is.defined(options.container)) {
+      if (is.string(options.container) && is.inArray(options.container, ['fs', 'zip'])) {
+        this.options.tileContainer = options.container;
+      } else {
+        throw is.invalidParameterError('container', 'one of: fs, zip', options.container);
+      }
+    }
+    // Layout
+    if (is.defined(options.layout)) {
+      if (is.string(options.layout) && is.inArray(options.layout, ['dz', 'google', 'iiif', 'zoomify'])) {
+        this.options.tileLayout = options.layout;
+      } else {
+        throw is.invalidParameterError('layout', 'one of: dz, google, iiif, zoomify', options.layout);
+      }
+    }
+    // Angle of rotation,
+    if (is.defined(options.angle)) {
+      if (is.integer(options.angle) && !(options.angle % 90)) {
+        this.options.tileAngle = options.angle;
+      } else {
+        throw is.invalidParameterError('angle', 'positive/negative multiple of 90', options.angle);
+      }
+    }
+    // Background colour
+    this._setBackgroundColourOption('tileBackground', options.background);
+    // Depth of tiles
+    if (is.defined(options.depth)) {
+      if (is.string(options.depth) && is.inArray(options.depth, ['onepixel', 'onetile', 'one'])) {
+        this.options.tileDepth = options.depth;
+      } else {
+        throw is.invalidParameterError('depth', 'one of: onepixel, onetile, one', options.depth);
+      }
+    }
+    // Threshold to skip blank tiles
+    if (is.defined(options.skipBlanks)) {
+      if (is.integer(options.skipBlanks) && is.inRange(options.skipBlanks, -1, 65535)) {
+        this.options.tileSkipBlanks = options.skipBlanks;
+      } else {
+        throw is.invalidParameterError('skipBlanks', 'integer between -1 and 255/65535', options.skipBlanks);
+      }
+    } else if (is.defined(options.layout) && options.layout === 'google') {
+      this.options.tileSkipBlanks = 5;
+    }
+    // Center image in tile
+    const centre = is.bool(options.center) ? options.center : options.centre;
+    if (is.defined(centre)) {
+      this._setBooleanOption('tileCentre', centre);
+    }
+    // @id attribute for IIIF layout
+    if (is.defined(options.id)) {
+      if (is.string(options.id)) {
+        this.options.tileId = options.id;
+      } else {
+        throw is.invalidParameterError('id', 'string', options.id);
+      }
+    }
+  }
+  // Format
+  if (is.inArray(this.options.formatOut, ['jpeg', 'png', 'webp'])) {
+    this.options.tileFormat = this.options.formatOut;
+  } else if (this.options.formatOut !== 'input') {
+    throw is.invalidParameterError('format', 'one of: jpeg, png, webp', this.options.formatOut);
+  }
+  return this._updateFormatOut('dz');
+}
+
+/**
+ * Update the output format unless options.force is false,
+ * in which case revert to input format.
+ * @private
+ * @param {string} formatOut
+ * @param {Object} [options]
+ * @param {boolean} [options.force=true] - force output format, otherwise attempt to use input format
+ * @returns {Sharp}
+ */
+function _updateFormatOut (formatOut, options) {
+  if (!(is.object(options) && options.force === false)) {
+    this.options.formatOut = formatOut;
+  }
+  return this;
+}
+
+/**
+ * Update a boolean attribute of the this.options Object.
+ * @private
+ * @param {string} key
+ * @param {boolean} val
+ * @throws {Error} Invalid key
+ */
+function _setBooleanOption (key, val) {
+  if (is.bool(val)) {
+    this.options[key] = val;
+  } else {
+    throw is.invalidParameterError(key, 'boolean', val);
+  }
+}
+
+/**
+ * Called by a WriteableStream to notify us it is ready for data.
+ * @private
+ */
+function _read () {
+  /* istanbul ignore else */
+  if (!this.options.streamOut) {
+    this.options.streamOut = true;
+    this._pipeline();
+  }
+}
+
+/**
+ * Invoke the C++ image processing pipeline
+ * Supports callback, stream and promise variants
+ * @private
+ */
+function _pipeline (callback) {
+  if (typeof callback === 'function') {
+    // output=file/buffer
+    if (this._isStreamInput()) {
+      // output=file/buffer, input=stream
+      this.on('finish', () => {
+        this._flattenBufferIn();
+        sharp.pipeline(this.options, callback);
+      });
+    } else {
+      // output=file/buffer, input=file/buffer
+      sharp.pipeline(this.options, callback);
+    }
+    return this;
+  } else if (this.options.streamOut) {
+    // output=stream
+    if (this._isStreamInput()) {
+      // output=stream, input=stream
+      this.once('finish', () => {
+        this._flattenBufferIn();
+        sharp.pipeline(this.options, (err, data, info) => {
+          if (err) {
+            this.emit('error', err);
+          } else {
+            this.emit('info', info);
+            this.push(data);
+          }
+          this.push(null);
+        });
+      });
+      if (this.streamInFinished) {
+        this.emit('finish');
+      }
+    } else {
+      // output=stream, input=file/buffer
+      sharp.pipeline(this.options, (err, data, info) => {
+        if (err) {
+          this.emit('error', err);
+        } else {
+          this.emit('info', info);
+          this.push(data);
+        }
+        this.push(null);
+      });
+    }
+    return this;
+  } else {
+    // output=promise
+    if (this._isStreamInput()) {
+      // output=promise, input=stream
+      return new Promise((resolve, reject) => {
+        this.once('finish', () => {
+          this._flattenBufferIn();
+          sharp.pipeline(this.options, (err, data, info) => {
+            if (err) {
+              reject(err);
+            } else {
+              if (this.options.resolveWithObject) {
+                resolve({ data, info });
+              } else {
+                resolve(data);
+              }
+            }
+          });
+        });
+      });
+    } else {
+      // output=promise, input=file/buffer
+      return new Promise((resolve, reject) => {
+        sharp.pipeline(this.options, (err, data, info) => {
+          if (err) {
+            reject(err);
+          } else {
+            if (this.options.resolveWithObject) {
+              resolve({ data: data, info: info });
+            } else {
+              resolve(data);
+            }
+          }
+        });
+      });
+    }
+  }
+}
+
+/**
+ * Decorate the Sharp prototype with output-related functions.
+ * @private
+ */
+module.exports = function (Sharp) {
+  Object.assign(Sharp.prototype, {
+    // Public
+    toFile,
+    toBuffer,
+    withMetadata,
+    toFormat,
+    jpeg,
+    png,
+    webp,
+    tiff,
+    avif,
+    heif,
+    gif,
+    raw,
+    tile,
+    // Private
+    _updateFormatOut,
+    _setBooleanOption,
+    _read,
+    _pipeline
+  });
+};

lib/platform.js

@@ -0,0 +1,25 @@
+'use strict';
+
+const detectLibc = require('detect-libc');
+
+const env = process.env;
+
+module.exports = function () {
+  const arch = env.npm_config_arch || process.arch;
+  const platform = env.npm_config_platform || process.platform;
+  /* istanbul ignore next */
+  const libc = (platform === 'linux' && detectLibc.isNonGlibcLinux) ? detectLibc.family : '';
+
+  const platformId = [`${platform}${libc}`];
+
+  if (arch === 'arm') {
+    const fallback = process.versions.electron ? '7' : '6';
+    platformId.push(`armv${env.npm_config_arm_version || process.config.variables.arm_version || fallback}`);
+  } else if (arch === 'arm64') {
+    platformId.push(`arm64v${env.npm_config_arm_version || '8'}`);
+  } else {
+    platformId.push(arch);
+  }
+
+  return platformId.join('-');
+};

lib/resize.js

@@ -0,0 +1,454 @@
+'use strict';
+
+const is = require('./is');
+
+/**
+ * Weighting to apply when using contain/cover fit.
+ * @member
+ * @private
+ */
+const gravity = {
+  center: 0,
+  centre: 0,
+  north: 1,
+  east: 2,
+  south: 3,
+  west: 4,
+  northeast: 5,
+  southeast: 6,
+  southwest: 7,
+  northwest: 8
+};
+
+/**
+ * Position to apply when using contain/cover fit.
+ * @member
+ * @private
+ */
+const position = {
+  top: 1,
+  right: 2,
+  bottom: 3,
+  left: 4,
+  'right top': 5,
+  'right bottom': 6,
+  'left bottom': 7,
+  'left top': 8
+};
+
+/**
+ * Strategies for automagic cover behaviour.
+ * @member
+ * @private
+ */
+const strategy = {
+  entropy: 16,
+  attention: 17
+};
+
+/**
+ * Reduction kernels.
+ * @member
+ * @private
+ */
+const kernel = {
+  nearest: 'nearest',
+  cubic: 'cubic',
+  mitchell: 'mitchell',
+  lanczos2: 'lanczos2',
+  lanczos3: 'lanczos3'
+};
+
+/**
+ * Methods by which an image can be resized to fit the provided dimensions.
+ * @member
+ * @private
+ */
+const fit = {
+  contain: 'contain',
+  cover: 'cover',
+  fill: 'fill',
+  inside: 'inside',
+  outside: 'outside'
+};
+
+/**
+ * Map external fit property to internal canvas property.
+ * @member
+ * @private
+ */
+const mapFitToCanvas = {
+  contain: 'embed',
+  cover: 'crop',
+  fill: 'ignore_aspect',
+  inside: 'max',
+  outside: 'min'
+};
+
+/**
+ * @private
+ */
+function isRotationExpected (options) {
+  return (options.angle % 360) !== 0 || options.useExifOrientation === true || options.rotationAngle !== 0;
+}
+
+/**
+ * Resize image to `width`, `height` or `width x height`.
+ *
+ * When both a `width` and `height` are provided, the possible methods by which the image should **fit** these are:
+ * - `cover`: (default) Preserving aspect ratio, ensure the image covers both provided dimensions by cropping/clipping to fit.
+ * - `contain`: Preserving aspect ratio, contain within both provided dimensions using "letterboxing" where necessary.
+ * - `fill`: Ignore the aspect ratio of the input and stretch to both provided dimensions.
+ * - `inside`: Preserving aspect ratio, resize the image to be as large as possible while ensuring its dimensions are less than or equal to both those specified.
+ * - `outside`: Preserving aspect ratio, resize the image to be as small as possible while ensuring its dimensions are greater than or equal to both those specified.
+ *
+ * Some of these values are based on the [object-fit](https://developer.mozilla.org/en-US/docs/Web/CSS/object-fit) CSS property.
+ *
+ * When using a `fit` of `cover` or `contain`, the default **position** is `centre`. Other options are:
+ * - `sharp.position`: `top`, `right top`, `right`, `right bottom`, `bottom`, `left bottom`, `left`, `left top`.
+ * - `sharp.gravity`: `north`, `northeast`, `east`, `southeast`, `south`, `southwest`, `west`, `northwest`, `center` or `centre`.
+ * - `sharp.strategy`: `cover` only, dynamically crop using either the `entropy` or `attention` strategy.
+ *
+ * Some of these values are based on the [object-position](https://developer.mozilla.org/en-US/docs/Web/CSS/object-position) CSS property.
+ *
+ * The experimental strategy-based approach resizes so one dimension is at its target length
+ * then repeatedly ranks edge regions, discarding the edge with the lowest score based on the selected strategy.
+ * - `entropy`: focus on the region with the highest [Shannon entropy](https://en.wikipedia.org/wiki/Entropy_%28information_theory%29).
+ * - `attention`: focus on the region with the highest luminance frequency, colour saturation and presence of skin tones.
+ *
+ * Possible interpolation kernels are:
+ * - `nearest`: Use [nearest neighbour interpolation](http://en.wikipedia.org/wiki/Nearest-neighbor_interpolation).
+ * - `cubic`: Use a [Catmull-Rom spline](https://en.wikipedia.org/wiki/Centripetal_Catmull%E2%80%93Rom_spline).
+ * - `mitchell`: Use a [Mitchell-Netravali spline](https://www.cs.utexas.edu/~fussell/courses/cs384g-fall2013/lectures/mitchell/Mitchell.pdf).
+ * - `lanczos2`: Use a [Lanczos kernel](https://en.wikipedia.org/wiki/Lanczos_resampling#Lanczos_kernel) with `a=2`.
+ * - `lanczos3`: Use a Lanczos kernel with `a=3` (the default).
+ *
+ * @example
+ * sharp(input)
+ *   .resize({ width: 100 })
+ *   .toBuffer()
+ *   .then(data => {
+ *     // 100 pixels wide, auto-scaled height
+ *   });
+ *
+ * @example
+ * sharp(input)
+ *   .resize({ height: 100 })
+ *   .toBuffer()
+ *   .then(data => {
+ *     // 100 pixels high, auto-scaled width
+ *   });
+ *
+ * @example
+ * sharp(input)
+ *   .resize(200, 300, {
+ *     kernel: sharp.kernel.nearest,
+ *     fit: 'contain',
+ *     position: 'right top',
+ *     background: { r: 255, g: 255, b: 255, alpha: 0.5 }
+ *   })
+ *   .toFile('output.png')
+ *   .then(() => {
+ *     // output.png is a 200 pixels wide and 300 pixels high image
+ *     // containing a nearest-neighbour scaled version
+ *     // contained within the north-east corner of a semi-transparent white canvas
+ *   });
+ *
+ * @example
+ * const transformer = sharp()
+ *   .resize({
+ *     width: 200,
+ *     height: 200,
+ *     fit: sharp.fit.cover,
+ *     position: sharp.strategy.entropy
+ *   });
+ * // Read image data from readableStream
+ * // Write 200px square auto-cropped image data to writableStream
+ * readableStream
+ *   .pipe(transformer)
+ *   .pipe(writableStream);
+ *
+ * @example
+ * sharp(input)
+ *   .resize(200, 200, {
+ *     fit: sharp.fit.inside,
+ *     withoutEnlargement: true
+ *   })
+ *   .toFormat('jpeg')
+ *   .toBuffer()
+ *   .then(function(outputBuffer) {
+ *     // outputBuffer contains JPEG image data
+ *     // no wider and no higher than 200 pixels
+ *     // and no larger than the input image
+ *   });
+ *
+ * @example
+ * const scaleByHalf = await sharp(input)
+ *   .metadata()
+ *   .then(({ width }) => sharp(input)
+ *     .resize(Math.round(width * 0.5))
+ *     .toBuffer()
+ *   );
+ *
+ * @param {number} [width] - pixels wide the resultant image should be. Use `null` or `undefined` to auto-scale the width to match the height.
+ * @param {number} [height] - pixels high the resultant image should be. Use `null` or `undefined` to auto-scale the height to match the width.
+ * @param {Object} [options]
+ * @param {String} [options.width] - alternative means of specifying `width`. If both are present this take priority.
+ * @param {String} [options.height] - alternative means of specifying `height`. If both are present this take priority.
+ * @param {String} [options.fit='cover'] - how the image should be resized to fit both provided dimensions, one of `cover`, `contain`, `fill`, `inside` or `outside`.
+ * @param {String} [options.position='centre'] - position, gravity or strategy to use when `fit` is `cover` or `contain`.
+ * @param {String|Object} [options.background={r: 0, g: 0, b: 0, alpha: 1}] - background colour when using a `fit` of `contain`, parsed by the [color](https://www.npmjs.org/package/color) module, defaults to black without transparency.
+ * @param {String} [options.kernel='lanczos3'] - the kernel to use for image reduction.
+ * @param {Boolean} [options.withoutEnlargement=false] - do not enlarge if the width *or* height are already less than the specified dimensions, equivalent to GraphicsMagick's `>` geometry option.
+ * @param {Boolean} [options.fastShrinkOnLoad=true] - take greater advantage of the JPEG and WebP shrink-on-load feature, which can lead to a slight moiré pattern on some images.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function resize (width, height, options) {
+  if (is.defined(width)) {
+    if (is.object(width) && !is.defined(options)) {
+      options = width;
+    } else if (is.integer(width) && width > 0) {
+      this.options.width = width;
+    } else {
+      throw is.invalidParameterError('width', 'positive integer', width);
+    }
+  } else {
+    this.options.width = -1;
+  }
+  if (is.defined(height)) {
+    if (is.integer(height) && height > 0) {
+      this.options.height = height;
+    } else {
+      throw is.invalidParameterError('height', 'positive integer', height);
+    }
+  } else {
+    this.options.height = -1;
+  }
+  if (is.object(options)) {
+    // Width
+    if (is.defined(options.width)) {
+      if (is.integer(options.width) && options.width > 0) {
+        this.options.width = options.width;
+      } else {
+        throw is.invalidParameterError('width', 'positive integer', options.width);
+      }
+    }
+    // Height
+    if (is.defined(options.height)) {
+      if (is.integer(options.height) && options.height > 0) {
+        this.options.height = options.height;
+      } else {
+        throw is.invalidParameterError('height', 'positive integer', options.height);
+      }
+    }
+    // Fit
+    if (is.defined(options.fit)) {
+      const canvas = mapFitToCanvas[options.fit];
+      if (is.string(canvas)) {
+        this.options.canvas = canvas;
+      } else {
+        throw is.invalidParameterError('fit', 'valid fit', options.fit);
+      }
+    }
+    // Position
+    if (is.defined(options.position)) {
+      const pos = is.integer(options.position)
+        ? options.position
+        : strategy[options.position] || position[options.position] || gravity[options.position];
+      if (is.integer(pos) && (is.inRange(pos, 0, 8) || is.inRange(pos, 16, 17))) {
+        this.options.position = pos;
+      } else {
+        throw is.invalidParameterError('position', 'valid position/gravity/strategy', options.position);
+      }
+    }
+    // Background
+    this._setBackgroundColourOption('resizeBackground', options.background);
+    // Kernel
+    if (is.defined(options.kernel)) {
+      if (is.string(kernel[options.kernel])) {
+        this.options.kernel = kernel[options.kernel];
+      } else {
+        throw is.invalidParameterError('kernel', 'valid kernel name', options.kernel);
+      }
+    }
+    // Without enlargement
+    if (is.defined(options.withoutEnlargement)) {
+      this._setBooleanOption('withoutEnlargement', options.withoutEnlargement);
+    }
+    // Shrink on load
+    if (is.defined(options.fastShrinkOnLoad)) {
+      this._setBooleanOption('fastShrinkOnLoad', options.fastShrinkOnLoad);
+    }
+  }
+  return this;
+}
+
+/**
+ * Extends/pads the edges of the image with the provided background colour.
+ * This operation will always occur after resizing and extraction, if any.
+ *
+ * @example
+ * // Resize to 140 pixels wide, then add 10 transparent pixels
+ * // to the top, left and right edges and 20 to the bottom edge
+ * sharp(input)
+ *   .resize(140)
+ *   .extend({
+ *     top: 10,
+ *     bottom: 20,
+ *     left: 10,
+ *     right: 10,
+ *     background: { r: 0, g: 0, b: 0, alpha: 0 }
+ *   })
+ *   ...
+ *
+* @example
+ * // Add a row of 10 red pixels to the bottom
+ * sharp(input)
+ *   .extend({
+ *     bottom: 10,
+ *     background: 'red'
+ *   })
+ *   ...
+ *
+ * @param {(number|Object)} extend - single pixel count to add to all edges or an Object with per-edge counts
+ * @param {number} [extend.top=0]
+ * @param {number} [extend.left=0]
+ * @param {number} [extend.bottom=0]
+ * @param {number} [extend.right=0]
+ * @param {String|Object} [extend.background={r: 0, g: 0, b: 0, alpha: 1}] - background colour, parsed by the [color](https://www.npmjs.org/package/color) module, defaults to black without transparency.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+*/
+function extend (extend) {
+  if (is.integer(extend) && extend > 0) {
+    this.options.extendTop = extend;
+    this.options.extendBottom = extend;
+    this.options.extendLeft = extend;
+    this.options.extendRight = extend;
+  } else if (is.object(extend)) {
+    if (is.defined(extend.top)) {
+      if (is.integer(extend.top) && extend.top >= 0) {
+        this.options.extendTop = extend.top;
+      } else {
+        throw is.invalidParameterError('top', 'positive integer', extend.top);
+      }
+    }
+    if (is.defined(extend.bottom)) {
+      if (is.integer(extend.bottom) && extend.bottom >= 0) {
+        this.options.extendBottom = extend.bottom;
+      } else {
+        throw is.invalidParameterError('bottom', 'positive integer', extend.bottom);
+      }
+    }
+    if (is.defined(extend.left)) {
+      if (is.integer(extend.left) && extend.left >= 0) {
+        this.options.extendLeft = extend.left;
+      } else {
+        throw is.invalidParameterError('left', 'positive integer', extend.left);
+      }
+    }
+    if (is.defined(extend.right)) {
+      if (is.integer(extend.right) && extend.right >= 0) {
+        this.options.extendRight = extend.right;
+      } else {
+        throw is.invalidParameterError('right', 'positive integer', extend.right);
+      }
+    }
+    this._setBackgroundColourOption('extendBackground', extend.background);
+  } else {
+    throw is.invalidParameterError('extend', 'integer or object', extend);
+  }
+  return this;
+}
+
+/**
+ * Extract/crop a region of the image.
+ *
+ * - Use `extract` before `resize` for pre-resize extraction.
+ * - Use `extract` after `resize` for post-resize extraction.
+ * - Use `extract` before and after for both.
+ *
+ * @example
+ * sharp(input)
+ *   .extract({ left: left, top: top, width: width, height: height })
+ *   .toFile(output, function(err) {
+ *     // Extract a region of the input image, saving in the same format.
+ *   });
+ * @example
+ * sharp(input)
+ *   .extract({ left: leftOffsetPre, top: topOffsetPre, width: widthPre, height: heightPre })
+ *   .resize(width, height)
+ *   .extract({ left: leftOffsetPost, top: topOffsetPost, width: widthPost, height: heightPost })
+ *   .toFile(output, function(err) {
+ *     // Extract a region, resize, then extract from the resized image
+ *   });
+ *
+ * @param {Object} options - describes the region to extract using integral pixel values
+ * @param {number} options.left - zero-indexed offset from left edge
+ * @param {number} options.top - zero-indexed offset from top edge
+ * @param {number} options.width - width of region to extract
+ * @param {number} options.height - height of region to extract
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function extract (options) {
+  const suffix = this.options.width === -1 && this.options.height === -1 ? 'Pre' : 'Post';
+  ['left', 'top', 'width', 'height'].forEach(function (name) {
+    const value = options[name];
+    if (is.integer(value) && value >= 0) {
+      this.options[name + (name === 'left' || name === 'top' ? 'Offset' : '') + suffix] = value;
+    } else {
+      throw is.invalidParameterError(name, 'integer', value);
+    }
+  }, this);
+  // Ensure existing rotation occurs before pre-resize extraction
+  if (suffix === 'Pre' && isRotationExpected(this.options)) {
+    this.options.rotateBeforePreExtract = true;
+  }
+  return this;
+}
+
+/**
+ * Trim "boring" pixels from all edges that contain values similar to the top-left pixel.
+ * Images consisting entirely of a single colour will calculate "boring" using the alpha channel, if any.
+ *
+ * The `info` response Object, obtained from callback of `.toFile()` or `.toBuffer()`,
+ * will contain `trimOffsetLeft` and `trimOffsetTop` properties.
+ *
+ * @param {number} [threshold=10] the allowed difference from the top-left pixel, a number greater than zero.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function trim (threshold) {
+  if (!is.defined(threshold)) {
+    this.options.trimThreshold = 10;
+  } else if (is.number(threshold) && threshold > 0) {
+    this.options.trimThreshold = threshold;
+  } else {
+    throw is.invalidParameterError('threshold', 'number greater than zero', threshold);
+  }
+  if (this.options.trimThreshold && isRotationExpected(this.options)) {
+    this.options.rotateBeforePreExtract = true;
+  }
+  return this;
+}
+
+/**
+ * Decorate the Sharp prototype with resize-related functions.
+ * @private
+ */
+module.exports = function (Sharp) {
+  Object.assign(Sharp.prototype, {
+    resize,
+    extend,
+    extract,
+    trim
+  });
+  // Class attributes
+  Sharp.gravity = gravity;
+  Sharp.strategy = strategy;
+  Sharp.kernel = kernel;
+  Sharp.fit = fit;
+  Sharp.position = position;
+};

lib/utility.js

@@ -0,0 +1,179 @@
+'use strict';
+
+const events = require('events');
+const detectLibc = require('detect-libc');
+
+const is = require('./is');
+const sharp = require('../build/Release/sharp.node');
+
+/**
+ * An Object containing nested boolean values representing the available input and output formats/methods.
+ * @member
+ * @example
+ * console.log(sharp.format);
+ * @returns {Object}
+ */
+const format = sharp.format();
+
+/**
+ * An Object containing the available interpolators and their proper values
+ * @readonly
+ * @enum {string}
+ */
+const interpolators = {
+  /** [Nearest neighbour interpolation](http://en.wikipedia.org/wiki/Nearest-neighbor_interpolation). Suitable for image enlargement only. */
+  nearest: 'nearest',
+  /** [Bilinear interpolation](http://en.wikipedia.org/wiki/Bilinear_interpolation). Faster than bicubic but with less smooth results. */
+  bilinear: 'bilinear',
+  /** [Bicubic interpolation](http://en.wikipedia.org/wiki/Bicubic_interpolation) (the default). */
+  bicubic: 'bicubic',
+  /** [LBB interpolation](https://github.com/jcupitt/libvips/blob/master/libvips/resample/lbb.cpp#L100). Prevents some "[acutance](http://en.wikipedia.org/wiki/Acutance)" but typically reduces performance by a factor of 2. */
+  locallyBoundedBicubic: 'lbb',
+  /** [Nohalo interpolation](http://eprints.soton.ac.uk/268086/). Prevents acutance but typically reduces performance by a factor of 3. */
+  nohalo: 'nohalo',
+  /** [VSQBS interpolation](https://github.com/jcupitt/libvips/blob/master/libvips/resample/vsqbs.cpp#L48). Prevents "staircasing" when enlarging. */
+  vertexSplitQuadraticBasisSpline: 'vsqbs'
+};
+
+/**
+ * An Object containing the version numbers of libvips and its dependencies.
+ * @member
+ * @example
+ * console.log(sharp.versions);
+ */
+let versions = {
+  vips: sharp.libvipsVersion()
+};
+try {
+  versions = require(`../vendor/${versions.vips}/versions.json`);
+} catch (err) {}
+
+/**
+ * Gets or, when options are provided, sets the limits of _libvips'_ operation cache.
+ * Existing entries in the cache will be trimmed after any change in limits.
+ * This method always returns cache statistics,
+ * useful for determining how much working memory is required for a particular task.
+ *
+ * @example
+ * const stats = sharp.cache();
+ * @example
+ * sharp.cache( { items: 200 } );
+ * sharp.cache( { files: 0 } );
+ * sharp.cache(false);
+ *
+ * @param {Object|boolean} [options=true] - Object with the following attributes, or boolean where true uses default cache settings and false removes all caching
+ * @param {number} [options.memory=50] - is the maximum memory in MB to use for this cache
+ * @param {number} [options.files=20] - is the maximum number of files to hold open
+ * @param {number} [options.items=100] - is the maximum number of operations to cache
+ * @returns {Object}
+ */
+function cache (options) {
+  if (is.bool(options)) {
+    if (options) {
+      // Default cache settings of 50MB, 20 files, 100 items
+      return sharp.cache(50, 20, 100);
+    } else {
+      return sharp.cache(0, 0, 0);
+    }
+  } else if (is.object(options)) {
+    return sharp.cache(options.memory, options.files, options.items);
+  } else {
+    return sharp.cache();
+  }
+}
+cache(true);
+
+/**
+ * Gets or, when a concurrency is provided, sets
+ * the number of threads _libvips'_ should create to process each image.
+ *
+ * The default value is the number of CPU cores,
+ * except when using glibc-based Linux without jemalloc,
+ * where the default is `1` to help reduce memory fragmentation.
+ *
+ * A value of `0` will reset this to the number of CPU cores.
+ *
+ * The maximum number of images that can be processed in parallel
+ * is limited by libuv's `UV_THREADPOOL_SIZE` environment variable.
+ *
+ * This method always returns the current concurrency.
+ *
+ * @example
+ * const threads = sharp.concurrency(); // 4
+ * sharp.concurrency(2); // 2
+ * sharp.concurrency(0); // 4
+ *
+ * @param {number} [concurrency]
+ * @returns {number} concurrency
+ */
+function concurrency (concurrency) {
+  return sharp.concurrency(is.integer(concurrency) ? concurrency : null);
+}
+/* istanbul ignore next */
+if (detectLibc.family === detectLibc.GLIBC && !sharp._isUsingJemalloc()) {
+  // Reduce default concurrency to 1 when using glibc memory allocator
+  sharp.concurrency(1);
+}
+
+/**
+ * An EventEmitter that emits a `change` event when a task is either:
+ * - queued, waiting for _libuv_ to provide a worker thread
+ * - complete
+ * @member
+ * @example
+ * sharp.queue.on('change', function(queueLength) {
+ *   console.log('Queue contains ' + queueLength + ' task(s)');
+ * });
+ */
+const queue = new events.EventEmitter();
+
+/**
+ * Provides access to internal task counters.
+ * - queue is the number of tasks this module has queued waiting for _libuv_ to provide a worker thread from its pool.
+ * - process is the number of resize tasks currently being processed.
+ *
+ * @example
+ * const counters = sharp.counters(); // { queue: 2, process: 4 }
+ *
+ * @returns {Object}
+ */
+function counters () {
+  return sharp.counters();
+}
+
+/**
+ * Get and set use of SIMD vector unit instructions.
+ * Requires libvips to have been compiled with liborc support.
+ *
+ * Improves the performance of `resize`, `blur` and `sharpen` operations
+ * by taking advantage of the SIMD vector unit of the CPU, e.g. Intel SSE and ARM NEON.
+ *
+ * @example
+ * const simd = sharp.simd();
+ * // simd is `true` if the runtime use of liborc is currently enabled
+ * @example
+ * const simd = sharp.simd(false);
+ * // prevent libvips from using liborc at runtime
+ *
+ * @param {boolean} [simd=true]
+ * @returns {boolean}
+ */
+function simd (simd) {
+  return sharp.simd(is.bool(simd) ? simd : null);
+}
+simd(true);
+
+/**
+ * Decorate the Sharp class with utility-related functions.
+ * @private
+ */
+module.exports = function (Sharp) {
+  Sharp.cache = cache;
+  Sharp.concurrency = concurrency;
+  Sharp.counters = counters;
+  Sharp.simd = simd;
+  Sharp.format = format;
+  Sharp.interpolators = interpolators;
+  Sharp.versions = versions;
+  Sharp.queue = queue;
+};

package.json

@@ -1,16 +1,100 @@
 {
   "name": "sharp",
-  "version": "0.5.1",
+  "description": "High performance Node.js image processing, the fastest module to resize JPEG, PNG, WebP, AVIF and TIFF images",
+  "version": "0.28.0",
   "author": "Lovell Fuller <npm@lovell.info>",
+  "homepage": "https://github.com/lovell/sharp",
   "contributors": [
     "Pierre Inglebert <pierre.inglebert@gmail.com>",
-    "Jonathan Ong <jonathanrichardong@gmail.com>"
+    "Jonathan Ong <jonathanrichardong@gmail.com>",
+    "Chanon Sajjamanochai <chanon.s@gmail.com>",
+    "Juliano Julio <julianojulio@gmail.com>",
+    "Daniel Gasienica <daniel@gasienica.ch>",
+    "Julian Walker <julian@fiftythree.com>",
+    "Amit Pitaru <pitaru.amit@gmail.com>",
+    "Brandon Aaron <hello.brandon@aaron.sh>",
+    "Andreas Lind <andreas@one.com>",
+    "Maurus Cuelenaere <mcuelenaere@gmail.com>",
+    "Linus Unnebäck <linus@folkdatorn.se>",
+    "Victor Mateevitsi <mvictoras@gmail.com>",
+    "Alaric Holloway <alaric.holloway@gmail.com>",
+    "Bernhard K. Weisshuhn <bkw@codingforce.com>",
+    "Chris Riley <criley@primedia.com>",
+    "David Carley <dacarley@gmail.com>",
+    "John Tobin <john@limelightmobileinc.com>",
+    "Kenton Gray <kentongray@gmail.com>",
+    "Felix Bünemann <Felix.Buenemann@gmail.com>",
+    "Samy Al Zahrani <samyalzahrany@gmail.com>",
+    "Chintan Thakkar <lemnisk8@gmail.com>",
+    "F. Orlando Galashan <frulo@gmx.de>",
+    "Kleis Auke Wolthuizen <info@kleisauke.nl>",
+    "Matt Hirsch <mhirsch@media.mit.edu>",
+    "Matthias Thoemmes <thoemmes@gmail.com>",
+    "Patrick Paskaris <patrick@paskaris.gr>",
+    "Jérémy Lal <kapouer@melix.org>",
+    "Rahul Nanwani <r.nanwani@gmail.com>",
+    "Alice Monday <alice0meta@gmail.com>",
+    "Kristo Jorgenson <kristo.jorgenson@gmail.com>",
+    "YvesBos <yves_bos@outlook.com>",
+    "Guy Maliar <guy@tailorbrands.com>",
+    "Nicolas Coden <nicolas@ncoden.fr>",
+    "Matt Parrish <matt.r.parrish@gmail.com>",
+    "Marcel Bretschneider <marcel.bretschneider@gmail.com>",
+    "Matthew McEachen <matthew+github@mceachen.org>",
+    "Jarda Kotěšovec <jarda.kotesovec@gmail.com>",
+    "Kenric D'Souza <kenric.dsouza@gmail.com>",
+    "Oleh Aleinyk <oleg.aleynik@gmail.com>",
+    "Marcel Bretschneider <marcel.bretschneider@gmail.com>",
+    "Andrea Bianco <andrea.bianco@unibas.ch>",
+    "Rik Heywood <rik@rik.org>",
+    "Thomas Parisot <hi@oncletom.io>",
+    "Nathan Graves <nathanrgraves+github@gmail.com>",
+    "Tom Lokhorst <tom@lokhorst.eu>",
+    "Espen Hovlandsdal <espen@hovlandsdal.com>",
+    "Sylvain Dumont <sylvain.dumont35@gmail.com>",
+    "Alun Davies <alun.owain.davies@googlemail.com>",
+    "Aidan Hoolachan <ajhoolachan21@gmail.com>",
+    "Axel Eirola <axel.eirola@iki.fi>",
+    "Freezy <freezy@xbmc.org>",
+    "Daiz <taneli.vatanen@gmail.com>",
+    "Julian Aubourg <j@ubourg.net>",
+    "Keith Belovay <keith@picthrive.com>",
+    "Michael B. Klein <mbklein@gmail.com>",
+    "Jordan Prudhomme <jordan@raboland.fr>",
+    "Ilya Ovdin <iovdin@gmail.com>",
+    "Andargor <andargor@yahoo.com>",
+    "Paul Neave <paul.neave@gmail.com>",
+    "Brendan Kennedy <brenwken@gmail.com>",
+    "Brychan Bennett-Odlum <git@brychan.io>",
+    "Edward Silverton <e.silverton@gmail.com>",
+    "Roman Malieiev <aromaleev@gmail.com>",
+    "Tomas Szabo <tomas.szabo@deftomat.com>",
+    "Robert O'Rourke <robert@o-rourke.org>",
+    "Guillermo Alfonso Varela Chouciño <guillevch@gmail.com>",
+    "Christian Flintrup <chr@gigahost.dk>",
+    "Manan Jadhav <manan@motionden.com>",
+    "Leon Radley <leon@radley.se>",
+    "alza54 <alza54@thiocod.in>"
   ],
-  "description": "High performance Node.js module to resize JPEG, PNG and WebP images using the libvips library",
   "scripts": {
-    "test": "node tests/unit && node tests/perf"
+    "install": "(node install/libvips && node install/dll-copy && prebuild-install) || (node-gyp rebuild && node install/dll-copy)",
+    "clean": "rm -rf node_modules/ build/ vendor/ .nyc_output/ coverage/ test/fixtures/output.*",
+    "test": "semistandard && cpplint && npm run test-unit && npm run test-licensing",
+    "test-unit": "nyc --reporter=lcov --branches=99 mocha --slow=1000 --timeout=60000 ./test/unit/*.js",
+    "test-licensing": "license-checker --production --summary --onlyAllow=\"Apache-2.0;BSD;ISC;MIT\"",
+    "test-coverage": "./test/coverage/report.sh",
+    "test-leak": "./test/leak/leak.sh",
+    "docs-build": "documentation lint lib && node docs/build && node docs/search-index/build",
+    "docs-serve": "cd docs && npx serve",
+    "docs-publish": "cd docs && npx firebase-tools deploy --project pixelplumbing --only hosting:pixelplumbing-sharp"
   },
-  "main": "index.js",
+  "main": "lib/index.js",
+  "files": [
+    "binding.gyp",
+    "install/**",
+    "lib/**",
+    "src/**"
+  ],
   "repository": {
     "type": "git",
     "url": "git://github.com/lovell/sharp"
@@ -19,31 +103,70 @@
     "jpeg",
     "png",
     "webp",
+    "avif",
     "tiff",
     "gif",
+    "svg",
+    "dzi",
+    "image",
     "resize",
     "thumbnail",
-    "sharpen",
     "crop",
     "embed",
     "libvips",
-    "vips",
-    "fast",
-    "buffer"
+    "vips"
   ],
   "dependencies": {
-    "nan": "^1.2.0",
-    "bluebird": "^2.1.2"
+    "color": "^3.1.3",
+    "detect-libc": "^1.0.3",
+    "node-addon-api": "^3.1.0",
+    "prebuild-install": "^6.0.1",
+    "semver": "^7.3.5",
+    "simple-get": "^3.1.0",
+    "tar-fs": "^2.1.1",
+    "tunnel-agent": "^0.6.0"
   },
   "devDependencies": {
-    "imagemagick": "^0.1.3",
-    "imagemagick-native": "^1.1.1",
-    "gm": "^1.16.0",
-    "async": "^0.9.0",
-    "benchmark": "^1.0.0"
+    "async": "^3.2.0",
+    "cc": "^3.0.1",
+    "decompress-zip": "^0.3.3",
+    "documentation": "^13.2.0",
+    "exif-reader": "^1.0.3",
+    "icc": "^2.0.0",
+    "license-checker": "^25.0.1",
+    "mocha": "^8.3.2",
+    "mock-fs": "^4.13.0",
+    "nyc": "^15.1.0",
+    "prebuild": "^10.0.1",
+    "rimraf": "^3.0.2",
+    "semistandard": "^16.0.0"
+  },
+  "license": "Apache-2.0",
+  "config": {
+    "libvips": "8.10.6",
+    "runtime": "napi",
+    "target": 3
   },
-  "license": "Apache 2.0",
   "engines": {
-    "node": ">=0.10"
+    "node": ">=10"
+  },
+  "funding": {
+    "url": "https://opencollective.com/libvips"
+  },
+  "binary": {
+    "napi_versions": [
+      3
+    ]
+  },
+  "semistandard": {
+    "env": [
+      "mocha"
+    ]
+  },
+  "cc": {
+    "linelength": "120",
+    "filter": [
+      "build/include"
+    ]
   }
 }

src/common.cc

@@ -0,0 +1,810 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <cstdlib>
+#include <string>
+#include <string.h>
+#include <vector>
+#include <queue>
+#include <map>
+#include <mutex>  // NOLINT(build/c++11)
+
+#include <napi.h>
+#include <vips/vips8>
+
+#include "common.h"
+
+using vips::VImage;
+
+namespace sharp {
+
+  // Convenience methods to access the attributes of a Napi::Object
+  bool HasAttr(Napi::Object obj, std::string attr) {
+    return obj.Has(attr);
+  }
+  std::string AttrAsStr(Napi::Object obj, std::string attr) {
+    return obj.Get(attr).As<Napi::String>();
+  }
+  uint32_t AttrAsUint32(Napi::Object obj, std::string attr) {
+    return obj.Get(attr).As<Napi::Number>().Uint32Value();
+  }
+  int32_t AttrAsInt32(Napi::Object obj, std::string attr) {
+    return obj.Get(attr).As<Napi::Number>().Int32Value();
+  }
+  int32_t AttrAsInt32(Napi::Object obj, unsigned int const attr) {
+    return obj.Get(attr).As<Napi::Number>().Int32Value();
+  }
+  double AttrAsDouble(Napi::Object obj, std::string attr) {
+    return obj.Get(attr).As<Napi::Number>().DoubleValue();
+  }
+  double AttrAsDouble(Napi::Object obj, unsigned int const attr) {
+    return obj.Get(attr).As<Napi::Number>().DoubleValue();
+  }
+  bool AttrAsBool(Napi::Object obj, std::string attr) {
+    return obj.Get(attr).As<Napi::Boolean>().Value();
+  }
+  std::vector<double> AttrAsVectorOfDouble(Napi::Object obj, std::string attr) {
+    Napi::Array napiArray = obj.Get(attr).As<Napi::Array>();
+    std::vector<double> vectorOfDouble(napiArray.Length());
+    for (unsigned int i = 0; i < napiArray.Length(); i++) {
+      vectorOfDouble[i] = AttrAsDouble(napiArray, i);
+    }
+    return vectorOfDouble;
+  }
+  std::vector<int32_t> AttrAsInt32Vector(Napi::Object obj, std::string attr) {
+    Napi::Array array = obj.Get(attr).As<Napi::Array>();
+    std::vector<int32_t> vector(array.Length());
+    for (unsigned int i = 0; i < array.Length(); i++) {
+      vector[i] = AttrAsInt32(array, i);
+    }
+    return vector;
+  }
+
+  // Create an InputDescriptor instance from a Napi::Object describing an input image
+  InputDescriptor* CreateInputDescriptor(Napi::Object input) {
+    InputDescriptor *descriptor = new InputDescriptor;
+    if (HasAttr(input, "file")) {
+      descriptor->file = AttrAsStr(input, "file");
+    } else if (HasAttr(input, "buffer")) {
+      Napi::Buffer<char> buffer = input.Get("buffer").As<Napi::Buffer<char>>();
+      descriptor->bufferLength = buffer.Length();
+      descriptor->buffer = buffer.Data();
+      descriptor->isBuffer = TRUE;
+    }
+    descriptor->failOnError = AttrAsBool(input, "failOnError");
+    // Density for vector-based input
+    if (HasAttr(input, "density")) {
+      descriptor->density = AttrAsDouble(input, "density");
+    }
+    // Raw pixel input
+    if (HasAttr(input, "rawChannels")) {
+      descriptor->rawChannels = AttrAsUint32(input, "rawChannels");
+      descriptor->rawWidth = AttrAsUint32(input, "rawWidth");
+      descriptor->rawHeight = AttrAsUint32(input, "rawHeight");
+    }
+    // Multi-page input (GIF, TIFF, PDF)
+    if (HasAttr(input, "pages")) {
+      descriptor->pages = AttrAsInt32(input, "pages");
+    }
+    if (HasAttr(input, "page")) {
+      descriptor->page = AttrAsUint32(input, "page");
+    }
+    // Multi-level input (OpenSlide)
+    if (HasAttr(input, "level")) {
+      descriptor->level = AttrAsUint32(input, "level");
+    }
+    // Create new image
+    if (HasAttr(input, "createChannels")) {
+      descriptor->createChannels = AttrAsUint32(input, "createChannels");
+      descriptor->createWidth = AttrAsUint32(input, "createWidth");
+      descriptor->createHeight = AttrAsUint32(input, "createHeight");
+      if (HasAttr(input, "createNoiseType")) {
+        descriptor->createNoiseType = AttrAsStr(input, "createNoiseType");
+        descriptor->createNoiseMean = AttrAsDouble(input, "createNoiseMean");
+        descriptor->createNoiseSigma = AttrAsDouble(input, "createNoiseSigma");
+      } else {
+        descriptor->createBackground = AttrAsVectorOfDouble(input, "createBackground");
+      }
+    }
+    // Limit input images to a given number of pixels, where pixels = width * height
+    descriptor->limitInputPixels = AttrAsUint32(input, "limitInputPixels");
+    // Allow switch from random to sequential access
+    descriptor->access = AttrAsBool(input, "sequentialRead") ? VIPS_ACCESS_SEQUENTIAL : VIPS_ACCESS_RANDOM;
+    return descriptor;
+  }
+
+  // How many tasks are in the queue?
+  volatile int counterQueue = 0;
+
+  // How many tasks are being processed?
+  volatile int counterProcess = 0;
+
+  // Filename extension checkers
+  static bool EndsWith(std::string const &str, std::string const &end) {
+    return str.length() >= end.length() && 0 == str.compare(str.length() - end.length(), end.length(), end);
+  }
+  bool IsJpeg(std::string const &str) {
+    return EndsWith(str, ".jpg") || EndsWith(str, ".jpeg") || EndsWith(str, ".JPG") || EndsWith(str, ".JPEG");
+  }
+  bool IsPng(std::string const &str) {
+    return EndsWith(str, ".png") || EndsWith(str, ".PNG");
+  }
+  bool IsWebp(std::string const &str) {
+    return EndsWith(str, ".webp") || EndsWith(str, ".WEBP");
+  }
+  bool IsGif(std::string const &str) {
+    return EndsWith(str, ".gif") || EndsWith(str, ".GIF");
+  }
+  bool IsTiff(std::string const &str) {
+    return EndsWith(str, ".tif") || EndsWith(str, ".tiff") || EndsWith(str, ".TIF") || EndsWith(str, ".TIFF");
+  }
+  bool IsHeic(std::string const &str) {
+    return EndsWith(str, ".heic") || EndsWith(str, ".HEIC");
+  }
+  bool IsHeif(std::string const &str) {
+    return EndsWith(str, ".heif") || EndsWith(str, ".HEIF") || IsHeic(str) || IsAvif(str);
+  }
+  bool IsAvif(std::string const &str) {
+    return EndsWith(str, ".avif") || EndsWith(str, ".AVIF");
+  }
+  bool IsDz(std::string const &str) {
+    return EndsWith(str, ".dzi") || EndsWith(str, ".DZI");
+  }
+  bool IsDzZip(std::string const &str) {
+    return EndsWith(str, ".zip") || EndsWith(str, ".ZIP") || EndsWith(str, ".szi") || EndsWith(str, ".SZI");
+  }
+  bool IsV(std::string const &str) {
+    return EndsWith(str, ".v") || EndsWith(str, ".V") || EndsWith(str, ".vips") || EndsWith(str, ".VIPS");
+  }
+
+  /*
+    Provide a string identifier for the given image type.
+  */
+  std::string ImageTypeId(ImageType const imageType) {
+    std::string id;
+    switch (imageType) {
+      case ImageType::JPEG: id = "jpeg"; break;
+      case ImageType::PNG: id = "png"; break;
+      case ImageType::WEBP: id = "webp"; break;
+      case ImageType::TIFF: id = "tiff"; break;
+      case ImageType::GIF: id = "gif"; break;
+      case ImageType::SVG: id = "svg"; break;
+      case ImageType::HEIF: id = "heif"; break;
+      case ImageType::PDF: id = "pdf"; break;
+      case ImageType::MAGICK: id = "magick"; break;
+      case ImageType::OPENSLIDE: id = "openslide"; break;
+      case ImageType::PPM: id = "ppm"; break;
+      case ImageType::FITS: id = "fits"; break;
+      case ImageType::EXR: id = "exr"; break;
+      case ImageType::VIPS: id = "vips"; break;
+      case ImageType::RAW: id = "raw"; break;
+      case ImageType::UNKNOWN: id = "unknown"; break;
+      case ImageType::MISSING: id = "missing"; break;
+    }
+    return id;
+  }
+
+  /**
+   * Regenerate this table with something like:
+   *
+   * $ vips -l foreign | grep -i load | awk '{ print $2, $1; }'
+   *
+   * Plus a bit of editing.
+   */
+  std::map<std::string, ImageType> loaderToType = {
+    { "VipsForeignLoadJpegFile", ImageType::JPEG },
+    { "VipsForeignLoadJpegBuffer", ImageType::JPEG },
+    { "VipsForeignLoadPngFile", ImageType::PNG },
+    { "VipsForeignLoadPngBuffer", ImageType::PNG },
+    { "VipsForeignLoadWebpFile", ImageType::WEBP },
+    { "VipsForeignLoadWebpBuffer", ImageType::WEBP },
+    { "VipsForeignLoadTiffFile", ImageType::TIFF },
+    { "VipsForeignLoadTiffBuffer", ImageType::TIFF },
+    { "VipsForeignLoadGifFile", ImageType::GIF },
+    { "VipsForeignLoadGifBuffer", ImageType::GIF },
+    { "VipsForeignLoadNsgifFile", ImageType::GIF },
+    { "VipsForeignLoadNsgifBuffer", ImageType::GIF },
+    { "VipsForeignLoadSvgFile", ImageType::SVG },
+    { "VipsForeignLoadSvgBuffer", ImageType::SVG },
+    { "VipsForeignLoadHeifFile", ImageType::HEIF },
+    { "VipsForeignLoadHeifBuffer", ImageType::HEIF },
+    { "VipsForeignLoadPdfFile", ImageType::PDF },
+    { "VipsForeignLoadPdfBuffer", ImageType::PDF },
+    { "VipsForeignLoadMagickFile", ImageType::MAGICK },
+    { "VipsForeignLoadMagickBuffer", ImageType::MAGICK },
+    { "VipsForeignLoadOpenslide", ImageType::OPENSLIDE },
+    { "VipsForeignLoadPpmFile", ImageType::PPM },
+    { "VipsForeignLoadFits", ImageType::FITS },
+    { "VipsForeignLoadOpenexr", ImageType::EXR },
+    { "VipsForeignLoadVips", ImageType::VIPS },
+    { "VipsForeignLoadRaw", ImageType::RAW }
+  };
+
+  /*
+    Determine image format of a buffer.
+  */
+  ImageType DetermineImageType(void *buffer, size_t const length) {
+    ImageType imageType = ImageType::UNKNOWN;
+    char const *load = vips_foreign_find_load_buffer(buffer, length);
+    if (load != nullptr) {
+      auto it = loaderToType.find(load);
+      if (it != loaderToType.end()) {
+        imageType = it->second;
+      }
+    }
+    return imageType;
+  }
+
+  /*
+    Determine image format, reads the first few bytes of the file
+  */
+  ImageType DetermineImageType(char const *file) {
+    ImageType imageType = ImageType::UNKNOWN;
+    char const *load = vips_foreign_find_load(file);
+    if (load != nullptr) {
+      auto it = loaderToType.find(load);
+      if (it != loaderToType.end()) {
+        imageType = it->second;
+      }
+    } else {
+      if (EndsWith(vips::VError().what(), " does not exist\n")) {
+        imageType = ImageType::MISSING;
+      }
+    }
+    return imageType;
+  }
+
+  /*
+    Does this image type support multiple pages?
+  */
+  bool ImageTypeSupportsPage(ImageType imageType) {
+    return
+      imageType == ImageType::WEBP ||
+      imageType == ImageType::MAGICK ||
+      imageType == ImageType::GIF ||
+      imageType == ImageType::TIFF ||
+      imageType == ImageType::HEIF ||
+      imageType == ImageType::PDF;
+  }
+
+  /*
+    Open an image from the given InputDescriptor (filesystem, compressed buffer, raw pixel data)
+  */
+  std::tuple<VImage, ImageType> OpenInput(InputDescriptor *descriptor) {
+    VImage image;
+    ImageType imageType;
+    if (descriptor->isBuffer) {
+      if (descriptor->rawChannels > 0) {
+        // Raw, uncompressed pixel data
+        image = VImage::new_from_memory(descriptor->buffer, descriptor->bufferLength,
+          descriptor->rawWidth, descriptor->rawHeight, descriptor->rawChannels, VIPS_FORMAT_UCHAR);
+        if (descriptor->rawChannels < 3) {
+          image.get_image()->Type = VIPS_INTERPRETATION_B_W;
+        } else {
+          image.get_image()->Type = VIPS_INTERPRETATION_sRGB;
+        }
+        imageType = ImageType::RAW;
+      } else {
+        // Compressed data
+        imageType = DetermineImageType(descriptor->buffer, descriptor->bufferLength);
+        if (imageType != ImageType::UNKNOWN) {
+          try {
+            vips::VOption *option = VImage::option()
+              ->set("access", descriptor->access)
+              ->set("fail", descriptor->failOnError);
+            if (imageType == ImageType::SVG) {
+              option->set("unlimited", TRUE);
+            }
+            if (imageType == ImageType::SVG || imageType == ImageType::PDF) {
+              option->set("dpi", descriptor->density);
+            }
+            if (imageType == ImageType::MAGICK) {
+              option->set("density", std::to_string(descriptor->density).data());
+            }
+            if (ImageTypeSupportsPage(imageType)) {
+              option->set("n", descriptor->pages);
+              option->set("page", descriptor->page);
+            }
+            if (imageType == ImageType::OPENSLIDE) {
+              option->set("level", descriptor->level);
+            }
+            image = VImage::new_from_buffer(descriptor->buffer, descriptor->bufferLength, nullptr, option);
+            if (imageType == ImageType::SVG || imageType == ImageType::PDF || imageType == ImageType::MAGICK) {
+              image = SetDensity(image, descriptor->density);
+            }
+          } catch (vips::VError const &err) {
+            throw vips::VError(std::string("Input buffer has corrupt header: ") + err.what());
+          }
+        } else {
+          throw vips::VError("Input buffer contains unsupported image format");
+        }
+      }
+    } else {
+      if (descriptor->createChannels > 0) {
+        // Create new image
+        if (descriptor->createNoiseType == "gaussian") {
+          int const channels = descriptor->createChannels;
+          image = VImage::new_matrix(descriptor->createWidth, descriptor->createHeight);
+          std::vector<VImage> bands = {};
+          bands.reserve(channels);
+          for (int _band = 0; _band < channels; _band++) {
+            bands.push_back(image.gaussnoise(
+              descriptor->createWidth,
+              descriptor->createHeight,
+              VImage::option()->set("mean", descriptor->createNoiseMean)->set("sigma", descriptor->createNoiseSigma)));
+          }
+          image = image.bandjoin(bands);
+          image = image.cast(VipsBandFormat::VIPS_FORMAT_UCHAR);
+          if (channels < 3) {
+            image = image.colourspace(VIPS_INTERPRETATION_B_W);
+          } else {
+            image = image.colourspace(VIPS_INTERPRETATION_sRGB);
+          }
+        } else {
+          std::vector<double> background = {
+            descriptor->createBackground[0],
+            descriptor->createBackground[1],
+            descriptor->createBackground[2]
+          };
+          if (descriptor->createChannels == 4) {
+            background.push_back(descriptor->createBackground[3]);
+          }
+          image = VImage::new_matrix(descriptor->createWidth, descriptor->createHeight).new_from_image(background);
+        }
+        image.get_image()->Type = VIPS_INTERPRETATION_sRGB;
+        imageType = ImageType::RAW;
+      } else {
+        // From filesystem
+        imageType = DetermineImageType(descriptor->file.data());
+        if (imageType == ImageType::MISSING) {
+          throw vips::VError("Input file is missing");
+        }
+        if (imageType != ImageType::UNKNOWN) {
+          try {
+            vips::VOption *option = VImage::option()
+              ->set("access", descriptor->access)
+              ->set("fail", descriptor->failOnError);
+            if (imageType == ImageType::SVG) {
+              option->set("unlimited", TRUE);
+            }
+            if (imageType == ImageType::SVG || imageType == ImageType::PDF) {
+              option->set("dpi", descriptor->density);
+            }
+            if (imageType == ImageType::MAGICK) {
+              option->set("density", std::to_string(descriptor->density).data());
+            }
+            if (ImageTypeSupportsPage(imageType)) {
+              option->set("n", descriptor->pages);
+              option->set("page", descriptor->page);
+            }
+            if (imageType == ImageType::OPENSLIDE) {
+              option->set("level", descriptor->level);
+            }
+            image = VImage::new_from_file(descriptor->file.data(), option);
+            if (imageType == ImageType::SVG || imageType == ImageType::PDF || imageType == ImageType::MAGICK) {
+              image = SetDensity(image, descriptor->density);
+            }
+          } catch (vips::VError const &err) {
+            throw vips::VError(std::string("Input file has corrupt header: ") + err.what());
+          }
+        } else {
+          throw vips::VError("Input file contains unsupported image format");
+        }
+      }
+    }
+    // Limit input images to a given number of pixels, where pixels = width * height
+    if (descriptor->limitInputPixels > 0 &&
+      static_cast<uint64_t>(image.width() * image.height()) > static_cast<uint64_t>(descriptor->limitInputPixels)) {
+      throw vips::VError("Input image exceeds pixel limit");
+    }
+    return std::make_tuple(image, imageType);
+  }
+
+  /*
+    Does this image have an embedded profile?
+  */
+  bool HasProfile(VImage image) {
+    return (image.get_typeof(VIPS_META_ICC_NAME) != 0) ? TRUE : FALSE;
+  }
+
+  /*
+    Does this image have an alpha channel?
+    Uses colour space interpretation with number of channels to guess this.
+  */
+  bool HasAlpha(VImage image) {
+    return image.has_alpha();
+  }
+
+  /*
+    Get EXIF Orientation of image, if any.
+  */
+  int ExifOrientation(VImage image) {
+    int orientation = 0;
+    if (image.get_typeof(VIPS_META_ORIENTATION) != 0) {
+      orientation = image.get_int(VIPS_META_ORIENTATION);
+    }
+    return orientation;
+  }
+
+  /*
+    Set EXIF Orientation of image.
+  */
+  VImage SetExifOrientation(VImage image, int const orientation) {
+    VImage copy = image.copy();
+    copy.set(VIPS_META_ORIENTATION, orientation);
+    return copy;
+  }
+
+  /*
+    Remove EXIF Orientation from image.
+  */
+  VImage RemoveExifOrientation(VImage image) {
+    VImage copy = image.copy();
+    copy.remove(VIPS_META_ORIENTATION);
+    return copy;
+  }
+
+  /*
+    Set animation properties if necessary.
+    Non-provided properties will be loaded from image.
+  */
+  VImage SetAnimationProperties(VImage image, int pageHeight, std::vector<int> delay, int loop) {
+    bool hasDelay = delay.size() != 1 || delay.front() != -1;
+
+    if (pageHeight == 0 && image.get_typeof(VIPS_META_PAGE_HEIGHT) == G_TYPE_INT) {
+      pageHeight = image.get_int(VIPS_META_PAGE_HEIGHT);
+    }
+
+    if (!hasDelay && image.get_typeof("delay") == VIPS_TYPE_ARRAY_INT) {
+      delay = image.get_array_int("delay");
+      hasDelay = true;
+    }
+
+    if (loop == -1 && image.get_typeof("loop") == G_TYPE_INT) {
+      loop = image.get_int("loop");
+    }
+
+    if (pageHeight == 0) return image;
+
+    // It is necessary to create the copy as otherwise, pageHeight will be ignored!
+    VImage copy = image.copy();
+
+    copy.set(VIPS_META_PAGE_HEIGHT, pageHeight);
+    if (hasDelay) copy.set("delay", delay);
+    if (loop != -1) copy.set("loop", loop);
+
+    return copy;
+  }
+
+  /*
+    Does this image have a non-default density?
+  */
+  bool HasDensity(VImage image) {
+    return image.xres() > 1.0;
+  }
+
+  /*
+    Get pixels/mm resolution as pixels/inch density.
+  */
+  int GetDensity(VImage image) {
+    return static_cast<int>(round(image.xres() * 25.4));
+  }
+
+  /*
+    Set pixels/mm resolution based on a pixels/inch density.
+  */
+  VImage SetDensity(VImage image, const double density) {
+    const double pixelsPerMm = density / 25.4;
+    VImage copy = image.copy();
+    copy.set("Xres", pixelsPerMm);
+    copy.set("Yres", pixelsPerMm);
+    copy.set(VIPS_META_RESOLUTION_UNIT, "in");
+    return copy;
+  }
+
+  /*
+    Check the proposed format supports the current dimensions.
+  */
+  void AssertImageTypeDimensions(VImage image, ImageType const imageType) {
+    const int height = image.get_typeof(VIPS_META_PAGE_HEIGHT) == G_TYPE_INT
+      ? image.get_int(VIPS_META_PAGE_HEIGHT)
+      : image.height();
+    if (imageType == ImageType::JPEG) {
+      if (image.width() > 65535 || height > 65535) {
+        throw vips::VError("Processed image is too large for the JPEG format");
+      }
+    } else if (imageType == ImageType::WEBP) {
+      if (image.width() > 16383 || height > 16383) {
+        throw vips::VError("Processed image is too large for the WebP format");
+      }
+    } else if (imageType == ImageType::GIF) {
+      if (image.width() > 65535 || height > 65535) {
+        throw vips::VError("Processed image is too large for the GIF format");
+      }
+    }
+  }
+
+  /*
+    Called when a Buffer undergoes GC, required to support mixed runtime libraries in Windows
+  */
+  std::function<void(void*, char*)> FreeCallback = [](void*, char* data) {
+    g_free(data);
+  };
+
+  /*
+    Temporary buffer of warnings
+  */
+  std::queue<std::string> vipsWarnings;
+  std::mutex vipsWarningsMutex;
+
+  /*
+    Called with warnings from the glib-registered "VIPS" domain
+  */
+  void VipsWarningCallback(char const* log_domain, GLogLevelFlags log_level, char const* message, void* ignore) {
+    std::lock_guard<std::mutex> lock(vipsWarningsMutex);
+    vipsWarnings.emplace(message);
+  }
+
+  /*
+    Pop the oldest warning message from the queue
+  */
+  std::string VipsWarningPop() {
+    std::string warning;
+    std::lock_guard<std::mutex> lock(vipsWarningsMutex);
+    if (!vipsWarnings.empty()) {
+      warning = vipsWarnings.front();
+      vipsWarnings.pop();
+    }
+    return warning;
+  }
+
+  /*
+    Calculate the (left, top) coordinates of the output image
+    within the input image, applying the given gravity during an embed.
+
+    @Azurebyte: We are basically swapping the inWidth and outWidth, inHeight and outHeight from the CalculateCrop function.
+  */
+  std::tuple<int, int> CalculateEmbedPosition(int const inWidth, int const inHeight,
+    int const outWidth, int const outHeight, int const gravity) {
+
+    int left = 0;
+    int top = 0;
+    switch (gravity) {
+      case 1:
+        // North
+        left = (outWidth - inWidth) / 2;
+        break;
+      case 2:
+        // East
+        left = outWidth - inWidth;
+        top = (outHeight - inHeight) / 2;
+        break;
+      case 3:
+        // South
+        left = (outWidth - inWidth) / 2;
+        top = outHeight - inHeight;
+        break;
+      case 4:
+        // West
+        top = (outHeight - inHeight) / 2;
+        break;
+      case 5:
+        // Northeast
+        left = outWidth - inWidth;
+        break;
+      case 6:
+        // Southeast
+        left = outWidth - inWidth;
+        top = outHeight - inHeight;
+        break;
+      case 7:
+        // Southwest
+        top = outHeight - inHeight;
+        break;
+      case 8:
+        // Northwest
+        // Which is the default is 0,0 so we do not assign anything here.
+        break;
+      default:
+        // Centre
+        left = (outWidth - inWidth) / 2;
+        top = (outHeight - inHeight) / 2;
+    }
+    return std::make_tuple(left, top);
+  }
+
+  /*
+    Calculate the (left, top) coordinates of the output image
+    within the input image, applying the given gravity during a crop.
+  */
+  std::tuple<int, int> CalculateCrop(int const inWidth, int const inHeight,
+    int const outWidth, int const outHeight, int const gravity) {
+
+    int left = 0;
+    int top = 0;
+    switch (gravity) {
+      case 1:
+        // North
+        left = (inWidth - outWidth + 1) / 2;
+        break;
+      case 2:
+        // East
+        left = inWidth - outWidth;
+        top = (inHeight - outHeight + 1) / 2;
+        break;
+      case 3:
+        // South
+        left = (inWidth - outWidth + 1) / 2;
+        top = inHeight - outHeight;
+        break;
+      case 4:
+        // West
+        top = (inHeight - outHeight + 1) / 2;
+        break;
+      case 5:
+        // Northeast
+        left = inWidth - outWidth;
+        break;
+      case 6:
+        // Southeast
+        left = inWidth - outWidth;
+        top = inHeight - outHeight;
+        break;
+      case 7:
+        // Southwest
+        top = inHeight - outHeight;
+        break;
+      case 8:
+        // Northwest
+        break;
+      default:
+        // Centre
+        left = (inWidth - outWidth + 1) / 2;
+        top = (inHeight - outHeight + 1) / 2;
+    }
+    return std::make_tuple(left, top);
+  }
+
+  /*
+    Calculate the (left, top) coordinates of the output image
+    within the input image, applying the given x and y offsets.
+  */
+  std::tuple<int, int> CalculateCrop(int const inWidth, int const inHeight,
+    int const outWidth, int const outHeight, int const x, int const y) {
+
+    // default values
+    int left = 0;
+    int top = 0;
+
+    // assign only if valid
+    if (x < (inWidth - outWidth)) {
+      left = x;
+    } else if (x >= (inWidth - outWidth)) {
+      left = inWidth - outWidth;
+    }
+
+    if (y < (inHeight - outHeight)) {
+      top = y;
+    } else if (y >= (inHeight - outHeight)) {
+      top = inHeight - outHeight;
+    }
+
+    return std::make_tuple(left, top);
+  }
+
+  /*
+    Are pixel values in this image 16-bit integer?
+  */
+  bool Is16Bit(VipsInterpretation const interpretation) {
+    return interpretation == VIPS_INTERPRETATION_RGB16 || interpretation == VIPS_INTERPRETATION_GREY16;
+  }
+
+  /*
+    Return the image alpha maximum. Useful for combining alpha bands. scRGB
+    images are 0 - 1 for image data, but the alpha is 0 - 255.
+  */
+  double MaximumImageAlpha(VipsInterpretation const interpretation) {
+    return Is16Bit(interpretation) ? 65535.0 : 255.0;
+  }
+
+  /*
+    Get boolean operation type from string
+  */
+  VipsOperationBoolean GetBooleanOperation(std::string const opStr) {
+    return static_cast<VipsOperationBoolean>(
+      vips_enum_from_nick(nullptr, VIPS_TYPE_OPERATION_BOOLEAN, opStr.data()));
+  }
+
+  /*
+    Get interpretation type from string
+  */
+  VipsInterpretation GetInterpretation(std::string const typeStr) {
+    return static_cast<VipsInterpretation>(
+      vips_enum_from_nick(nullptr, VIPS_TYPE_INTERPRETATION, typeStr.data()));
+  }
+
+  /*
+    Convert RGBA value to another colourspace
+  */
+  std::vector<double> GetRgbaAsColourspace(std::vector<double> const rgba, VipsInterpretation const interpretation) {
+    int const bands = static_cast<int>(rgba.size());
+    if (bands < 3 || interpretation == VIPS_INTERPRETATION_sRGB || interpretation == VIPS_INTERPRETATION_RGB) {
+      return rgba;
+    } else {
+      VImage pixel = VImage::new_matrix(1, 1);
+      pixel.set("bands", bands);
+      pixel = pixel.new_from_image(rgba);
+      pixel = pixel.colourspace(interpretation, VImage::option()->set("source_space", VIPS_INTERPRETATION_sRGB));
+      return pixel(0, 0);
+    }
+  }
+
+  /*
+    Apply the alpha channel to a given colour
+  */
+  std::tuple<VImage, std::vector<double>> ApplyAlpha(VImage image, std::vector<double> colour) {
+    // Scale up 8-bit values to match 16-bit input image
+    double const multiplier = sharp::Is16Bit(image.interpretation()) ? 256.0 : 1.0;
+    // Create alphaColour colour
+    std::vector<double> alphaColour;
+    if (image.bands() > 2) {
+      alphaColour = {
+        multiplier * colour[0],
+        multiplier * colour[1],
+        multiplier * colour[2]
+      };
+    } else {
+      // Convert sRGB to greyscale
+      alphaColour = { multiplier * (
+        0.2126 * colour[0] +
+        0.7152 * colour[1] +
+        0.0722 * colour[2])
+      };
+    }
+    // Add alpha channel to alphaColour colour
+    if (colour[3] < 255.0 || HasAlpha(image)) {
+      alphaColour.push_back(colour[3] * multiplier);
+    }
+    // Ensure alphaColour colour uses correct colourspace
+    alphaColour = sharp::GetRgbaAsColourspace(alphaColour, image.interpretation());
+    // Add non-transparent alpha channel, if required
+    if (colour[3] < 255.0 && !HasAlpha(image)) {
+      image = image.bandjoin(
+        VImage::new_matrix(image.width(), image.height()).new_from_image(255 * multiplier));
+    }
+    return std::make_tuple(image, alphaColour);
+  }
+
+  /*
+    Removes alpha channel, if any.
+  */
+  VImage RemoveAlpha(VImage image) {
+    if (HasAlpha(image)) {
+      image = image.extract_band(0, VImage::option()->set("n", image.bands() - 1));
+    }
+    return image;
+  }
+
+  /*
+    Ensures alpha channel, if missing.
+  */
+  VImage EnsureAlpha(VImage image) {
+    if (!HasAlpha(image)) {
+      std::vector<double> alpha;
+      alpha.push_back(sharp::MaximumImageAlpha(image.interpretation()));
+      image = image.bandjoin_const(alpha);
+    }
+    return image;
+  }
+}  // namespace sharp

src/common.h

@@ -0,0 +1,303 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef SRC_COMMON_H_
+#define SRC_COMMON_H_
+
+#include <string>
+#include <tuple>
+#include <vector>
+
+#include <napi.h>
+#include <vips/vips8>
+
+// Verify platform and compiler compatibility
+
+#if (VIPS_MAJOR_VERSION < 8) || \
+  (VIPS_MAJOR_VERSION == 8 && VIPS_MINOR_VERSION < 10) || \
+  (VIPS_MAJOR_VERSION == 8 && VIPS_MINOR_VERSION == 10 && VIPS_MICRO_VERSION < 6)
+#error "libvips version 8.10.6+ is required - please see https://sharp.pixelplumbing.com/install"
+#endif
+
+#if ((!defined(__clang__)) && defined(__GNUC__) && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)))
+#error "GCC version 4.6+ is required for C++11 features - please see https://sharp.pixelplumbing.com/install"
+#endif
+
+#if (defined(__clang__) && defined(__has_feature))
+#if (!__has_feature(cxx_range_for))
+#error "clang version 3.0+ is required for C++11 features - please see https://sharp.pixelplumbing.com/install"
+#endif
+#endif
+
+using vips::VImage;
+
+namespace sharp {
+
+  struct InputDescriptor {  // NOLINT(runtime/indentation_namespace)
+    std::string name;
+    std::string file;
+    char *buffer;
+    bool failOnError;
+    int limitInputPixels;
+    VipsAccess access;
+    size_t bufferLength;
+    bool isBuffer;
+    double density;
+    int rawChannels;
+    int rawWidth;
+    int rawHeight;
+    int pages;
+    int page;
+    int level;
+    int createChannels;
+    int createWidth;
+    int createHeight;
+    std::vector<double> createBackground;
+    std::string createNoiseType;
+    double createNoiseMean;
+    double createNoiseSigma;
+
+    InputDescriptor():
+      buffer(nullptr),
+      failOnError(TRUE),
+      limitInputPixels(0x3FFF * 0x3FFF),
+      access(VIPS_ACCESS_RANDOM),
+      bufferLength(0),
+      isBuffer(FALSE),
+      density(72.0),
+      rawChannels(0),
+      rawWidth(0),
+      rawHeight(0),
+      pages(1),
+      page(0),
+      level(0),
+      createChannels(0),
+      createWidth(0),
+      createHeight(0),
+      createBackground{ 0.0, 0.0, 0.0, 255.0 },
+      createNoiseMean(0.0),
+      createNoiseSigma(0.0) {}
+  };
+
+  // Convenience methods to access the attributes of a Napi::Object
+  bool HasAttr(Napi::Object obj, std::string attr);
+  std::string AttrAsStr(Napi::Object obj, std::string attr);
+  uint32_t AttrAsUint32(Napi::Object obj, std::string attr);
+  int32_t AttrAsInt32(Napi::Object obj, std::string attr);
+  int32_t AttrAsInt32(Napi::Object obj, unsigned int const attr);
+  double AttrAsDouble(Napi::Object obj, std::string attr);
+  double AttrAsDouble(Napi::Object obj, unsigned int const attr);
+  bool AttrAsBool(Napi::Object obj, std::string attr);
+  std::vector<double> AttrAsVectorOfDouble(Napi::Object obj, std::string attr);
+  std::vector<int32_t> AttrAsInt32Vector(Napi::Object obj, std::string attr);
+
+  // Create an InputDescriptor instance from a Napi::Object describing an input image
+  InputDescriptor* CreateInputDescriptor(Napi::Object input);
+
+  enum class ImageType {
+    JPEG,
+    PNG,
+    WEBP,
+    TIFF,
+    GIF,
+    SVG,
+    HEIF,
+    PDF,
+    MAGICK,
+    OPENSLIDE,
+    PPM,
+    FITS,
+    EXR,
+    VIPS,
+    RAW,
+    UNKNOWN,
+    MISSING
+  };
+
+  // How many tasks are in the queue?
+  extern volatile int counterQueue;
+
+  // How many tasks are being processed?
+  extern volatile int counterProcess;
+
+  // Filename extension checkers
+  bool IsJpeg(std::string const &str);
+  bool IsPng(std::string const &str);
+  bool IsWebp(std::string const &str);
+  bool IsGif(std::string const &str);
+  bool IsTiff(std::string const &str);
+  bool IsHeic(std::string const &str);
+  bool IsHeif(std::string const &str);
+  bool IsAvif(std::string const &str);
+  bool IsDz(std::string const &str);
+  bool IsDzZip(std::string const &str);
+  bool IsV(std::string const &str);
+
+  /*
+    Provide a string identifier for the given image type.
+  */
+  std::string ImageTypeId(ImageType const imageType);
+
+  /*
+    Determine image format of a buffer.
+  */
+  ImageType DetermineImageType(void *buffer, size_t const length);
+
+  /*
+    Determine image format of a file.
+  */
+  ImageType DetermineImageType(char const *file);
+
+  /*
+    Does this image type support multiple pages?
+  */
+  bool ImageTypeSupportsPage(ImageType imageType);
+
+  /*
+    Open an image from the given InputDescriptor (filesystem, compressed buffer, raw pixel data)
+  */
+  std::tuple<VImage, ImageType> OpenInput(InputDescriptor *descriptor);
+
+  /*
+    Does this image have an embedded profile?
+  */
+  bool HasProfile(VImage image);
+
+  /*
+    Does this image have an alpha channel?
+    Uses colour space interpretation with number of channels to guess this.
+  */
+  bool HasAlpha(VImage image);
+
+  /*
+    Get EXIF Orientation of image, if any.
+  */
+  int ExifOrientation(VImage image);
+
+  /*
+    Set EXIF Orientation of image.
+  */
+  VImage SetExifOrientation(VImage image, int const orientation);
+
+  /*
+    Remove EXIF Orientation from image.
+  */
+  VImage RemoveExifOrientation(VImage image);
+
+  /*
+    Set animation properties if necessary.
+    Non-provided properties will be loaded from image.
+  */
+  VImage SetAnimationProperties(VImage image, int pageHeight, std::vector<int> delay, int loop);
+
+  /*
+    Does this image have a non-default density?
+  */
+  bool HasDensity(VImage image);
+
+  /*
+    Get pixels/mm resolution as pixels/inch density.
+  */
+  int GetDensity(VImage image);
+
+  /*
+    Set pixels/mm resolution based on a pixels/inch density.
+  */
+  VImage SetDensity(VImage image, const double density);
+
+  /*
+    Check the proposed format supports the current dimensions.
+  */
+  void AssertImageTypeDimensions(VImage image, ImageType const imageType);
+
+  /*
+    Called when a Buffer undergoes GC, required to support mixed runtime libraries in Windows
+  */
+  extern std::function<void(void*, char*)> FreeCallback;
+
+  /*
+    Called with warnings from the glib-registered "VIPS" domain
+  */
+  void VipsWarningCallback(char const* log_domain, GLogLevelFlags log_level, char const* message, void* ignore);
+
+  /*
+    Pop the oldest warning message from the queue
+  */
+  std::string VipsWarningPop();
+
+  /*
+    Calculate the (left, top) coordinates of the output image
+    within the input image, applying the given gravity during an embed.
+  */
+  std::tuple<int, int> CalculateEmbedPosition(int const inWidth, int const inHeight,
+    int const outWidth, int const outHeight, int const gravity);
+
+  /*
+    Calculate the (left, top) coordinates of the output image
+    within the input image, applying the given gravity.
+  */
+  std::tuple<int, int> CalculateCrop(int const inWidth, int const inHeight,
+    int const outWidth, int const outHeight, int const gravity);
+
+  /*
+    Calculate the (left, top) coordinates of the output image
+    within the input image, applying the given x and y offsets of the output image.
+  */
+  std::tuple<int, int> CalculateCrop(int const inWidth, int const inHeight,
+    int const outWidth, int const outHeight, int const x, int const y);
+
+  /*
+    Are pixel values in this image 16-bit integer?
+  */
+  bool Is16Bit(VipsInterpretation const interpretation);
+
+  /*
+    Return the image alpha maximum. Useful for combining alpha bands. scRGB
+    images are 0 - 1 for image data, but the alpha is 0 - 255.
+  */
+  double MaximumImageAlpha(VipsInterpretation const interpretation);
+
+  /*
+    Get boolean operation type from string
+  */
+  VipsOperationBoolean GetBooleanOperation(std::string const opStr);
+
+  /*
+    Get interpretation type from string
+  */
+  VipsInterpretation GetInterpretation(std::string const typeStr);
+
+  /*
+    Convert RGBA value to another colourspace
+  */
+  std::vector<double> GetRgbaAsColourspace(std::vector<double> const rgba, VipsInterpretation const interpretation);
+
+  /*
+    Apply the alpha channel to a given colour
+   */
+  std::tuple<VImage, std::vector<double>> ApplyAlpha(VImage image, std::vector<double> colour);
+
+  /*
+    Removes alpha channel, if any.
+  */
+  VImage RemoveAlpha(VImage image);
+
+  /*
+    Ensures alpha channel, if missing.
+  */
+  VImage EnsureAlpha(VImage image);
+
+}  // namespace sharp
+
+#endif  // SRC_COMMON_H_

src/libvips/cplusplus/VConnection.cpp

@@ -0,0 +1,178 @@
+/* Object part of the VSource and VTarget class
+ */
+
+/*
+
+    Copyright (C) 1991-2001 The National Gallery
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+    02110-1301  USA
+
+ */
+
+/*
+
+    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
+
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /*HAVE_CONFIG_H*/
+#include <vips/intl.h>
+
+#include <vips/vips8>
+
+#include <vips/debug.h>
+
+/*
+#define VIPS_DEBUG
+#define VIPS_DEBUG_VERBOSE
+ */
+
+VIPS_NAMESPACE_START
+
+VSource 
+VSource::new_from_descriptor( int descriptor )
+{
+	VipsSource *input;
+
+	if( !(input = vips_source_new_from_descriptor( descriptor )) )
+		throw VError();
+
+	VSource out( input ); 
+
+	return( out ); 
+}
+
+VSource 
+VSource::new_from_file( const char *filename )
+{
+	VipsSource *input;
+
+	if( !(input = vips_source_new_from_file( filename )) )
+		throw VError();
+
+	VSource out( input ); 
+
+	return( out ); 
+}
+
+VSource 
+VSource::new_from_blob( VipsBlob *blob )
+{
+	VipsSource *input;
+
+	if( !(input = vips_source_new_from_blob( blob )) )
+		throw VError();
+
+	VSource out( input ); 
+
+	return( out ); 
+}
+
+VSource 
+VSource::new_from_memory( const void *data, 
+	size_t size )
+{
+	VipsSource *input;
+
+	if( !(input = vips_source_new_from_memory( data, size )) )
+		throw VError();
+
+	VSource out( input ); 
+
+	return( out ); 
+}
+
+VSource 
+VSource::new_from_options( const char *options )
+{
+	VipsSource *input;
+
+	if( !(input = vips_source_new_from_options( options )) )
+		throw VError();
+
+	VSource out( input ); 
+
+	return( out ); 
+}
+
+VOption *
+VOption::set( const char *name, const VSource value )
+{
+	Pair *pair = new Pair( name );
+
+	pair->input = true;
+	g_value_init( &pair->value, VIPS_TYPE_SOURCE );
+	g_value_set_object( &pair->value, value.get_source() );
+	options.push_back( pair );
+
+	return( this );
+}
+
+VTarget 
+VTarget::new_to_descriptor( int descriptor )
+{
+	VipsTarget *output;
+
+	if( !(output = vips_target_new_to_descriptor( descriptor )) )
+		throw VError();
+
+	VTarget out( output ); 
+
+	return( out ); 
+}
+
+VTarget 
+VTarget::new_to_file( const char *filename )
+{
+	VipsTarget *output;
+
+	if( !(output = vips_target_new_to_file( filename )) )
+		throw VError();
+
+	VTarget out( output ); 
+
+	return( out ); 
+}
+
+VTarget 
+VTarget::new_to_memory()
+{
+	VipsTarget *output;
+
+	if( !(output = vips_target_new_to_memory()) )
+		throw VError();
+
+	VTarget out( output ); 
+
+	return( out ); 
+}
+
+VOption *
+VOption::set( const char *name, const VTarget value )
+{
+	Pair *pair = new Pair( name );
+
+	pair->input = true;
+	g_value_init( &pair->value, VIPS_TYPE_TARGET );
+	g_value_set_object( &pair->value, value.get_target() );
+	options.push_back( pair );
+
+	return( this );
+}
+
+VIPS_NAMESPACE_END

src/libvips/cplusplus/VError.cpp

@@ -0,0 +1,50 @@
+// Code for error type
+
+/*
+
+    Copyright (C) 1991-2001 The National Gallery
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+    02110-1301  USA
+
+ */
+
+/*
+
+    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
+
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /*HAVE_CONFIG_H*/
+#include <vips/intl.h>
+
+#include <vips/vips8>
+
+VIPS_NAMESPACE_START
+
+std::ostream &operator<<( std::ostream &file, const VError &err )
+{
+	err.ostream_print( file );
+	return( file );
+}
+
+void VError::ostream_print( std::ostream &file ) const
+{
+	file << _what;
+}
+
+VIPS_NAMESPACE_END

src/libvips/cplusplus/VInterpolate.cpp

@@ -0,0 +1,76 @@
+/* Object part of VInterpolate class
+ */
+
+/*
+
+    Copyright (C) 1991-2001 The National Gallery
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+    02110-1301  USA
+
+ */
+
+/*
+
+    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
+
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /*HAVE_CONFIG_H*/
+#include <vips/intl.h>
+
+#include <vips/vips8>
+
+#include <vips/debug.h>
+
+/*
+#define VIPS_DEBUG
+#define VIPS_DEBUG_VERBOSE
+ */
+
+VIPS_NAMESPACE_START
+
+VInterpolate 
+VInterpolate::new_from_name( const char *name, VOption *options )
+{
+	VipsInterpolate *interp;
+
+	if( !(interp = vips_interpolate_new( name )) ) {
+		delete options; 
+		throw VError(); 
+	}
+	delete options; 
+
+	VInterpolate out( interp ); 
+
+	return( out ); 
+}
+
+VOption *
+VOption::set( const char *name, const VInterpolate value )
+{
+	Pair *pair = new Pair( name );
+
+	pair->input = true;
+	g_value_init( &pair->value, VIPS_TYPE_INTERPOLATE );
+	g_value_set_object( &pair->value, value.get_interpolate() );
+	options.push_back( pair );
+
+	return( this );
+}
+
+VIPS_NAMESPACE_END

src/metadata.cc

@@ -0,0 +1,265 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <numeric>
+#include <vector>
+
+#include <napi.h>
+#include <vips/vips8>
+
+#include "common.h"
+#include "metadata.h"
+
+class MetadataWorker : public Napi::AsyncWorker {
+ public:
+  MetadataWorker(Napi::Function callback, MetadataBaton *baton, Napi::Function debuglog) :
+    Napi::AsyncWorker(callback), baton(baton), debuglog(Napi::Persistent(debuglog)) {}
+  ~MetadataWorker() {}
+
+  void Execute() {
+    // Decrement queued task counter
+    g_atomic_int_dec_and_test(&sharp::counterQueue);
+
+    vips::VImage image;
+    sharp::ImageType imageType = sharp::ImageType::UNKNOWN;
+    try {
+      std::tie(image, imageType) = OpenInput(baton->input);
+    } catch (vips::VError const &err) {
+      (baton->err).append(err.what());
+    }
+    if (imageType != sharp::ImageType::UNKNOWN) {
+      // Image type
+      baton->format = sharp::ImageTypeId(imageType);
+      // VipsImage attributes
+      baton->width = image.width();
+      baton->height = image.height();
+      baton->space = vips_enum_nick(VIPS_TYPE_INTERPRETATION, image.interpretation());
+      baton->channels = image.bands();
+      baton->depth = vips_enum_nick(VIPS_TYPE_BAND_FORMAT, image.format());
+      if (sharp::HasDensity(image)) {
+        baton->density = sharp::GetDensity(image);
+      }
+      if (image.get_typeof("jpeg-chroma-subsample") == VIPS_TYPE_REF_STRING) {
+        baton->chromaSubsampling = image.get_string("jpeg-chroma-subsample");
+      }
+      if (image.get_typeof("interlaced") == G_TYPE_INT) {
+        baton->isProgressive = image.get_int("interlaced") == 1;
+      }
+      if (image.get_typeof("palette-bit-depth") == G_TYPE_INT) {
+        baton->paletteBitDepth = image.get_int("palette-bit-depth");
+      }
+      if (image.get_typeof(VIPS_META_N_PAGES) == G_TYPE_INT) {
+        baton->pages = image.get_int(VIPS_META_N_PAGES);
+      }
+      if (image.get_typeof(VIPS_META_PAGE_HEIGHT) == G_TYPE_INT) {
+        baton->pageHeight = image.get_int(VIPS_META_PAGE_HEIGHT);
+      }
+      if (image.get_typeof("loop") == G_TYPE_INT) {
+        baton->loop = image.get_int("loop");
+      }
+      if (image.get_typeof("delay") == VIPS_TYPE_ARRAY_INT) {
+        baton->delay = image.get_array_int("delay");
+      }
+      if (image.get_typeof("heif-primary") == G_TYPE_INT) {
+        baton->pagePrimary = image.get_int("heif-primary");
+      }
+      if (image.get_typeof("heif-compression") == VIPS_TYPE_REF_STRING) {
+        baton->compression = image.get_string("heif-compression");
+      }
+      if (image.get_typeof("openslide.level-count") == VIPS_TYPE_REF_STRING) {
+        int const levels = std::stoi(image.get_string("openslide.level-count"));
+        for (int l = 0; l < levels; l++) {
+          std::string prefix = "openslide.level[" + std::to_string(l) + "].";
+          int const width = std::stoi(image.get_string((prefix + "width").data()));
+          int const height = std::stoi(image.get_string((prefix + "height").data()));
+          baton->levels.push_back(std::pair<int, int>(width, height));
+        }
+      }
+      baton->hasProfile = sharp::HasProfile(image);
+      // Derived attributes
+      baton->hasAlpha = sharp::HasAlpha(image);
+      baton->orientation = sharp::ExifOrientation(image);
+      // EXIF
+      if (image.get_typeof(VIPS_META_EXIF_NAME) == VIPS_TYPE_BLOB) {
+        size_t exifLength;
+        void const *exif = image.get_blob(VIPS_META_EXIF_NAME, &exifLength);
+        baton->exif = static_cast<char*>(g_malloc(exifLength));
+        memcpy(baton->exif, exif, exifLength);
+        baton->exifLength = exifLength;
+      }
+      // ICC profile
+      if (image.get_typeof(VIPS_META_ICC_NAME) == VIPS_TYPE_BLOB) {
+        size_t iccLength;
+        void const *icc = image.get_blob(VIPS_META_ICC_NAME, &iccLength);
+        baton->icc = static_cast<char*>(g_malloc(iccLength));
+        memcpy(baton->icc, icc, iccLength);
+        baton->iccLength = iccLength;
+      }
+      // IPTC
+      if (image.get_typeof(VIPS_META_IPTC_NAME) == VIPS_TYPE_BLOB) {
+        size_t iptcLength;
+        void const *iptc = image.get_blob(VIPS_META_IPTC_NAME, &iptcLength);
+        baton->iptc = static_cast<char *>(g_malloc(iptcLength));
+        memcpy(baton->iptc, iptc, iptcLength);
+        baton->iptcLength = iptcLength;
+      }
+      // XMP
+      if (image.get_typeof(VIPS_META_XMP_NAME) == VIPS_TYPE_BLOB) {
+        size_t xmpLength;
+        void const *xmp = image.get_blob(VIPS_META_XMP_NAME, &xmpLength);
+        baton->xmp = static_cast<char *>(g_malloc(xmpLength));
+        memcpy(baton->xmp, xmp, xmpLength);
+        baton->xmpLength = xmpLength;
+      }
+      // TIFFTAG_PHOTOSHOP
+      if (image.get_typeof(VIPS_META_PHOTOSHOP_NAME) == VIPS_TYPE_BLOB) {
+        size_t tifftagPhotoshopLength;
+        void const *tifftagPhotoshop = image.get_blob(VIPS_META_PHOTOSHOP_NAME, &tifftagPhotoshopLength);
+        baton->tifftagPhotoshop = static_cast<char *>(g_malloc(tifftagPhotoshopLength));
+        memcpy(baton->tifftagPhotoshop, tifftagPhotoshop, tifftagPhotoshopLength);
+        baton->tifftagPhotoshopLength = tifftagPhotoshopLength;
+      }
+    }
+
+    // Clean up
+    vips_error_clear();
+    vips_thread_shutdown();
+  }
+
+  void OnOK() {
+    Napi::Env env = Env();
+    Napi::HandleScope scope(env);
+
+    // Handle warnings
+    std::string warning = sharp::VipsWarningPop();
+    while (!warning.empty()) {
+      debuglog.Call({ Napi::String::New(env, warning) });
+      warning = sharp::VipsWarningPop();
+    }
+
+    if (baton->err.empty()) {
+      Napi::Object info = Napi::Object::New(env);
+      info.Set("format", baton->format);
+      if (baton->input->bufferLength > 0) {
+        info.Set("size", baton->input->bufferLength);
+      }
+      info.Set("width", baton->width);
+      info.Set("height", baton->height);
+      info.Set("space", baton->space);
+      info.Set("channels", baton->channels);
+      info.Set("depth", baton->depth);
+      if (baton->density > 0) {
+        info.Set("density", baton->density);
+      }
+      if (!baton->chromaSubsampling.empty()) {
+        info.Set("chromaSubsampling", baton->chromaSubsampling);
+      }
+      info.Set("isProgressive", baton->isProgressive);
+      if (baton->paletteBitDepth > 0) {
+        info.Set("paletteBitDepth", baton->paletteBitDepth);
+      }
+      if (baton->pages > 0) {
+        info.Set("pages", baton->pages);
+      }
+      if (baton->pageHeight > 0) {
+        info.Set("pageHeight", baton->pageHeight);
+      }
+      if (baton->loop >= 0) {
+        info.Set("loop", baton->loop);
+      }
+      if (!baton->delay.empty()) {
+        int i = 0;
+        Napi::Array delay = Napi::Array::New(env, static_cast<size_t>(baton->delay.size()));
+        for (int const d : baton->delay) {
+          delay.Set(i++, d);
+        }
+        info.Set("delay", delay);
+      }
+      if (baton->pagePrimary > -1) {
+        info.Set("pagePrimary", baton->pagePrimary);
+      }
+      if (!baton->compression.empty()) {
+        info.Set("compression", baton->compression);
+      }
+      if (!baton->levels.empty()) {
+        int i = 0;
+        Napi::Array levels = Napi::Array::New(env, static_cast<size_t>(baton->levels.size()));
+        for (std::pair<int, int> const &l : baton->levels) {
+          Napi::Object level = Napi::Object::New(env);
+          level.Set("width", l.first);
+          level.Set("height", l.second);
+          levels.Set(i++, level);
+        }
+        info.Set("levels", levels);
+      }
+      info.Set("hasProfile", baton->hasProfile);
+      info.Set("hasAlpha", baton->hasAlpha);
+      if (baton->orientation > 0) {
+        info.Set("orientation", baton->orientation);
+      }
+      if (baton->exifLength > 0) {
+        info.Set("exif", Napi::Buffer<char>::New(env, baton->exif, baton->exifLength, sharp::FreeCallback));
+      }
+      if (baton->iccLength > 0) {
+        info.Set("icc", Napi::Buffer<char>::New(env, baton->icc, baton->iccLength, sharp::FreeCallback));
+      }
+      if (baton->iptcLength > 0) {
+        info.Set("iptc", Napi::Buffer<char>::New(env, baton->iptc, baton->iptcLength, sharp::FreeCallback));
+      }
+      if (baton->xmpLength > 0) {
+        info.Set("xmp", Napi::Buffer<char>::New(env, baton->xmp, baton->xmpLength, sharp::FreeCallback));
+      }
+      if (baton->tifftagPhotoshopLength > 0) {
+        info.Set("tifftagPhotoshop",
+          Napi::Buffer<char>::New(env, baton->tifftagPhotoshop, baton->tifftagPhotoshopLength, sharp::FreeCallback));
+      }
+      Callback().MakeCallback(Receiver().Value(), { env.Null(), info });
+    } else {
+      Callback().MakeCallback(Receiver().Value(), { Napi::Error::New(env, baton->err).Value() });
+    }
+
+    delete baton->input;
+    delete baton;
+  }
+
+ private:
+  MetadataBaton* baton;
+  Napi::FunctionReference debuglog;
+};
+
+/*
+  metadata(options, callback)
+*/
+Napi::Value metadata(const Napi::CallbackInfo& info) {
+  // V8 objects are converted to non-V8 types held in the baton struct
+  MetadataBaton *baton = new MetadataBaton;
+  Napi::Object options = info[0].As<Napi::Object>();
+
+  // Input
+  baton->input = sharp::CreateInputDescriptor(options.Get("input").As<Napi::Object>());
+
+  // Function to notify of libvips warnings
+  Napi::Function debuglog = options.Get("debuglog").As<Napi::Function>();
+
+  // Join queue for worker thread
+  Napi::Function callback = info[1].As<Napi::Function>();
+  MetadataWorker *worker = new MetadataWorker(callback, baton, debuglog);
+  worker->Receiver().Set("options", options);
+  worker->Queue();
+
+  // Increment queued task counter
+  g_atomic_int_inc(&sharp::counterQueue);
+
+  return info.Env().Undefined();
+}

src/metadata.h

@@ -0,0 +1,88 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef SRC_METADATA_H_
+#define SRC_METADATA_H_
+
+#include <string>
+#include <napi.h>
+
+#include "./common.h"
+
+struct MetadataBaton {
+  // Input
+  sharp::InputDescriptor *input;
+  // Output
+  std::string format;
+  int width;
+  int height;
+  std::string space;
+  int channels;
+  std::string depth;
+  int density;
+  std::string chromaSubsampling;
+  bool isProgressive;
+  int paletteBitDepth;
+  int pages;
+  int pageHeight;
+  int loop;
+  std::vector<int> delay;
+  int pagePrimary;
+  std::string compression;
+  std::vector<std::pair<int, int>> levels;
+  bool hasProfile;
+  bool hasAlpha;
+  int orientation;
+  char *exif;
+  size_t exifLength;
+  char *icc;
+  size_t iccLength;
+  char *iptc;
+  size_t iptcLength;
+  char *xmp;
+  size_t xmpLength;
+  char *tifftagPhotoshop;
+  size_t tifftagPhotoshopLength;
+  std::string err;
+
+  MetadataBaton():
+    input(nullptr),
+    width(0),
+    height(0),
+    channels(0),
+    density(0),
+    isProgressive(false),
+    paletteBitDepth(0),
+    pages(0),
+    pageHeight(0),
+    loop(-1),
+    pagePrimary(-1),
+    hasProfile(false),
+    hasAlpha(false),
+    orientation(0),
+    exif(nullptr),
+    exifLength(0),
+    icc(nullptr),
+    iccLength(0),
+    iptc(nullptr),
+    iptcLength(0),
+    xmp(nullptr),
+    xmpLength(0),
+    tifftagPhotoshop(nullptr),
+    tifftagPhotoshopLength(0) {}
+};
+
+Napi::Value metadata(const Napi::CallbackInfo& info);
+
+#endif  // SRC_METADATA_H_

src/operations.cc

@@ -0,0 +1,278 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <algorithm>
+#include <functional>
+#include <memory>
+#include <tuple>
+#include <vector>
+
+#include <vips/vips8>
+
+#include "common.h"
+#include "operations.h"
+
+using vips::VImage;
+using vips::VError;
+
+namespace sharp {
+  /*
+   * Tint an image using the specified chroma, preserving the original image luminance
+   */
+  VImage Tint(VImage image, double const a, double const b) {
+    // Get original colourspace
+    VipsInterpretation typeBeforeTint = image.interpretation();
+    if (typeBeforeTint == VIPS_INTERPRETATION_RGB) {
+      typeBeforeTint = VIPS_INTERPRETATION_sRGB;
+    }
+    // Extract luminance
+    VImage luminance = image.colourspace(VIPS_INTERPRETATION_LAB)[0];
+    // Create the tinted version by combining the L from the original and the chroma from the tint
+    std::vector<double> chroma {a, b};
+    VImage tinted = luminance
+      .bandjoin(chroma)
+      .copy(VImage::option()->set("interpretation", VIPS_INTERPRETATION_LAB))
+      .colourspace(typeBeforeTint);
+    // Attach original alpha channel, if any
+    if (HasAlpha(image)) {
+      // Extract original alpha channel
+      VImage alpha = image[image.bands() - 1];
+      // Join alpha channel to normalised image
+      tinted = tinted.bandjoin(alpha);
+    }
+    return tinted;
+  }
+
+  /*
+   * Stretch luminance to cover full dynamic range.
+   */
+  VImage Normalise(VImage image) {
+    // Get original colourspace
+    VipsInterpretation typeBeforeNormalize = image.interpretation();
+    if (typeBeforeNormalize == VIPS_INTERPRETATION_RGB) {
+      typeBeforeNormalize = VIPS_INTERPRETATION_sRGB;
+    }
+    // Convert to LAB colourspace
+    VImage lab = image.colourspace(VIPS_INTERPRETATION_LAB);
+    // Extract luminance
+    VImage luminance = lab[0];
+    // Find luminance range
+    VImage stats = luminance.stats();
+    double min = stats(0, 0)[0];
+    double max = stats(1, 0)[0];
+    if (min != max) {
+      // Extract chroma
+      VImage chroma = lab.extract_band(1, VImage::option()->set("n", 2));
+      // Calculate multiplication factor and addition
+      double f = 100.0 / (max - min);
+      double a = -(min * f);
+      // Scale luminance, join to chroma, convert back to original colourspace
+      VImage normalized = luminance.linear(f, a).bandjoin(chroma).colourspace(typeBeforeNormalize);
+      // Attach original alpha channel, if any
+      if (HasAlpha(image)) {
+        // Extract original alpha channel
+        VImage alpha = image[image.bands() - 1];
+        // Join alpha channel to normalised image
+        return normalized.bandjoin(alpha);
+      } else {
+        return normalized;
+      }
+    }
+    return image;
+  }
+
+  /*
+   * Gamma encoding/decoding
+   */
+  VImage Gamma(VImage image, double const exponent) {
+    if (HasAlpha(image)) {
+      // Separate alpha channel
+      VImage alpha = image[image.bands() - 1];
+      return RemoveAlpha(image).gamma(VImage::option()->set("exponent", exponent)).bandjoin(alpha);
+    } else {
+      return image.gamma(VImage::option()->set("exponent", exponent));
+    }
+  }
+
+  /*
+   * Gaussian blur. Use sigma of -1.0 for fast blur.
+   */
+  VImage Blur(VImage image, double const sigma) {
+    if (sigma == -1.0) {
+      // Fast, mild blur - averages neighbouring pixels
+      VImage blur = VImage::new_matrixv(3, 3,
+        1.0, 1.0, 1.0,
+        1.0, 1.0, 1.0,
+        1.0, 1.0, 1.0);
+      blur.set("scale", 9.0);
+      return image.conv(blur);
+    } else {
+      // Slower, accurate Gaussian blur
+      return image.gaussblur(sigma);
+    }
+  }
+
+  /*
+   * Convolution with a kernel.
+   */
+  VImage Convolve(VImage image, int const width, int const height,
+    double const scale, double const offset,
+    std::unique_ptr<double[]> const &kernel_v
+  ) {
+    VImage kernel = VImage::new_from_memory(
+      kernel_v.get(),
+      width * height * sizeof(double),
+      width,
+      height,
+      1,
+      VIPS_FORMAT_DOUBLE);
+    kernel.set("scale", scale);
+    kernel.set("offset", offset);
+
+    return image.conv(kernel);
+  }
+
+  /*
+   * Recomb with a Matrix of the given bands/channel size.
+   * Eg. RGB will be a 3x3 matrix.
+   */
+  VImage Recomb(VImage image, std::unique_ptr<double[]> const &matrix) {
+    double *m = matrix.get();
+    image = image.colourspace(VIPS_INTERPRETATION_sRGB);
+    return image
+      .recomb(image.bands() == 3
+        ? VImage::new_from_memory(
+          m, 9 * sizeof(double), 3, 3, 1, VIPS_FORMAT_DOUBLE
+        )
+        : VImage::new_matrixv(4, 4,
+          m[0], m[1], m[2], 0.0,
+          m[3], m[4], m[5], 0.0,
+          m[6], m[7], m[8], 0.0,
+          0.0, 0.0, 0.0, 1.0));
+  }
+
+  VImage Modulate(VImage image, double const brightness, double const saturation, int const hue) {
+    if (HasAlpha(image)) {
+      // Separate alpha channel
+      VImage alpha = image[image.bands() - 1];
+      return RemoveAlpha(image)
+        .colourspace(VIPS_INTERPRETATION_LCH)
+        .linear(
+          { brightness, saturation, 1},
+          { 0.0, 0.0, static_cast<double>(hue) }
+        )
+        .colourspace(VIPS_INTERPRETATION_sRGB)
+        .bandjoin(alpha);
+    } else {
+      return image
+        .colourspace(VIPS_INTERPRETATION_LCH)
+        .linear(
+          { brightness, saturation, 1 },
+          { 0.0, 0.0, static_cast<double>(hue) }
+        )
+        .colourspace(VIPS_INTERPRETATION_sRGB);
+    }
+  }
+
+  /*
+   * Sharpen flat and jagged areas. Use sigma of -1.0 for fast sharpen.
+   */
+  VImage Sharpen(VImage image, double const sigma, double const flat, double const jagged) {
+    if (sigma == -1.0) {
+      // Fast, mild sharpen
+      VImage sharpen = VImage::new_matrixv(3, 3,
+        -1.0, -1.0, -1.0,
+        -1.0, 32.0, -1.0,
+        -1.0, -1.0, -1.0);
+      sharpen.set("scale", 24.0);
+      return image.conv(sharpen);
+    } else {
+      // Slow, accurate sharpen in LAB colour space, with control over flat vs jagged areas
+      VipsInterpretation colourspaceBeforeSharpen = image.interpretation();
+      if (colourspaceBeforeSharpen == VIPS_INTERPRETATION_RGB) {
+        colourspaceBeforeSharpen = VIPS_INTERPRETATION_sRGB;
+      }
+      return image.sharpen(
+        VImage::option()->set("sigma", sigma)->set("m1", flat)->set("m2", jagged))
+        .colourspace(colourspaceBeforeSharpen);
+    }
+  }
+
+  VImage Threshold(VImage image, double const threshold, bool const thresholdGrayscale) {
+    if (!thresholdGrayscale) {
+      return image >= threshold;
+    }
+    return image.colourspace(VIPS_INTERPRETATION_B_W) >= threshold;
+  }
+
+  /*
+    Perform boolean/bitwise operation on image color channels - results in one channel image
+  */
+  VImage Bandbool(VImage image, VipsOperationBoolean const boolean) {
+    image = image.bandbool(boolean);
+    return image.copy(VImage::option()->set("interpretation", VIPS_INTERPRETATION_B_W));
+  }
+
+  /*
+    Perform bitwise boolean operation between images
+  */
+  VImage Boolean(VImage image, VImage imageR, VipsOperationBoolean const boolean) {
+    return image.boolean(imageR, boolean);
+  }
+
+  /*
+    Trim an image
+  */
+  VImage Trim(VImage image, double const threshold) {
+    if (image.width() < 3 && image.height() < 3) {
+      throw VError("Image to trim must be at least 3x3 pixels");
+    }
+    // Top-left pixel provides the background colour
+    VImage background = image.extract_area(0, 0, 1, 1);
+    if (HasAlpha(background)) {
+      background = background.flatten();
+    }
+    int left, top, width, height;
+    left = image.find_trim(&top, &width, &height, VImage::option()
+      ->set("background", background(0, 0))
+      ->set("threshold", threshold));
+    if (width == 0 || height == 0) {
+      if (HasAlpha(image)) {
+        // Search alpha channel
+        VImage alpha = image[image.bands() - 1];
+        VImage backgroundAlpha = alpha.extract_area(0, 0, 1, 1);
+        left = alpha.find_trim(&top, &width, &height, VImage::option()
+          ->set("background", backgroundAlpha(0, 0))
+          ->set("threshold", threshold));
+      }
+      if (width == 0 || height == 0) {
+        throw VError("Unexpected error while trimming. Try to lower the tolerance");
+      }
+    }
+    return image.extract_area(left, top, width, height);
+  }
+
+  /*
+   * Calculate (a * in + b)
+   */
+  VImage Linear(VImage image, double const a, double const b) {
+    if (HasAlpha(image)) {
+      // Separate alpha channel
+      VImage alpha = image[image.bands() - 1];
+      return RemoveAlpha(image).linear(a, b).bandjoin(alpha);
+    } else {
+      return image.linear(a, b);
+    }
+  }
+}  // namespace sharp

src/operations.h

@@ -0,0 +1,97 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef SRC_OPERATIONS_H_
+#define SRC_OPERATIONS_H_
+
+#include <algorithm>
+#include <functional>
+#include <memory>
+#include <tuple>
+#include <vips/vips8>
+
+using vips::VImage;
+
+namespace sharp {
+
+  /*
+   * Tint an image using the specified chroma, preserving the original image luminance
+   */
+  VImage Tint(VImage image, double const a, double const b);
+
+  /*
+   * Stretch luminance to cover full dynamic range.
+   */
+  VImage Normalise(VImage image);
+
+  /*
+   * Gamma encoding/decoding
+   */
+  VImage Gamma(VImage image, double const exponent);
+
+  /*
+   * Gaussian blur. Use sigma of -1.0 for fast blur.
+   */
+  VImage Blur(VImage image, double const sigma);
+
+  /*
+   * Convolution with a kernel.
+   */
+  VImage Convolve(VImage image, int const width, int const height,
+    double const scale, double const offset, std::unique_ptr<double[]> const &kernel_v);
+
+  /*
+   * Sharpen flat and jagged areas. Use sigma of -1.0 for fast sharpen.
+   */
+  VImage Sharpen(VImage image, double const sigma, double const flat, double const jagged);
+
+  /*
+    Threshold an image
+  */
+  VImage Threshold(VImage image, double const threshold, bool const thresholdColor);
+
+  /*
+    Perform boolean/bitwise operation on image color channels - results in one channel image
+  */
+  VImage Bandbool(VImage image, VipsOperationBoolean const boolean);
+
+  /*
+    Perform bitwise boolean operation between images
+  */
+  VImage Boolean(VImage image, VImage imageR, VipsOperationBoolean const boolean);
+
+  /*
+    Trim an image
+  */
+  VImage Trim(VImage image, double const threshold);
+
+  /*
+   * Linear adjustment (a * in + b)
+   */
+  VImage Linear(VImage image, double const a, double const b);
+
+  /*
+   * Recomb with a Matrix of the given bands/channel size.
+   * Eg. RGB will be a 3x3 matrix.
+   */
+  VImage Recomb(VImage image, std::unique_ptr<double[]> const &matrix);
+
+  /*
+   * Modulate brightness, saturation and hue
+   */
+  VImage Modulate(VImage image, double const brightness, double const saturation, int const hue);
+
+}  // namespace sharp
+
+#endif  // SRC_OPERATIONS_H_

src/pipeline.h

@@ -0,0 +1,315 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef SRC_PIPELINE_H_
+#define SRC_PIPELINE_H_
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <napi.h>
+#include <vips/vips8>
+
+#include "./common.h"
+
+Napi::Value pipeline(const Napi::CallbackInfo& info);
+
+enum class Canvas {
+  CROP,
+  EMBED,
+  MAX,
+  MIN,
+  IGNORE_ASPECT
+};
+
+struct Composite {
+  sharp::InputDescriptor *input;
+  VipsBlendMode mode;
+  int gravity;
+  int left;
+  int top;
+  bool hasOffset;
+  bool tile;
+  bool premultiplied;
+
+  Composite():
+    input(nullptr),
+    mode(VIPS_BLEND_MODE_OVER),
+    gravity(0),
+    left(0),
+    top(0),
+    hasOffset(false),
+    tile(false),
+    premultiplied(false) {}
+};
+
+struct PipelineBaton {
+  sharp::InputDescriptor *input;
+  std::string formatOut;
+  std::string fileOut;
+  void *bufferOut;
+  size_t bufferOutLength;
+  std::vector<Composite *> composite;
+  std::vector<sharp::InputDescriptor *> joinChannelIn;
+  int topOffsetPre;
+  int leftOffsetPre;
+  int widthPre;
+  int heightPre;
+  int topOffsetPost;
+  int leftOffsetPost;
+  int widthPost;
+  int heightPost;
+  int width;
+  int height;
+  int channels;
+  Canvas canvas;
+  int position;
+  std::vector<double> resizeBackground;
+  bool hasCropOffset;
+  int cropOffsetLeft;
+  int cropOffsetTop;
+  bool premultiplied;
+  bool tileCentre;
+  std::string kernel;
+  bool fastShrinkOnLoad;
+  double tintA;
+  double tintB;
+  bool flatten;
+  std::vector<double> flattenBackground;
+  bool negate;
+  double blurSigma;
+  double brightness;
+  double saturation;
+  int hue;
+  int medianSize;
+  double sharpenSigma;
+  double sharpenFlat;
+  double sharpenJagged;
+  int threshold;
+  bool thresholdGrayscale;
+  double trimThreshold;
+  int trimOffsetLeft;
+  int trimOffsetTop;
+  double linearA;
+  double linearB;
+  double gamma;
+  double gammaOut;
+  bool greyscale;
+  bool normalise;
+  bool useExifOrientation;
+  int angle;
+  double rotationAngle;
+  std::vector<double> rotationBackground;
+  bool rotateBeforePreExtract;
+  bool flip;
+  bool flop;
+  int extendTop;
+  int extendBottom;
+  int extendLeft;
+  int extendRight;
+  std::vector<double> extendBackground;
+  bool withoutEnlargement;
+  std::vector<double> affineMatrix;
+  std::vector<double> affineBackground;
+  double affineIdx;
+  double affineIdy;
+  double affineOdx;
+  double affineOdy;
+  vips::VInterpolate affineInterpolator;
+  int jpegQuality;
+  bool jpegProgressive;
+  std::string jpegChromaSubsampling;
+  bool jpegTrellisQuantisation;
+  int jpegQuantisationTable;
+  bool jpegOvershootDeringing;
+  bool jpegOptimiseScans;
+  bool jpegOptimiseCoding;
+  bool pngProgressive;
+  int pngCompressionLevel;
+  bool pngAdaptiveFiltering;
+  bool pngPalette;
+  int pngQuality;
+  int pngColours;
+  double pngDither;
+  int webpQuality;
+  int webpAlphaQuality;
+  bool webpNearLossless;
+  bool webpLossless;
+  bool webpSmartSubsample;
+  int webpReductionEffort;
+  int tiffQuality;
+  VipsForeignTiffCompression tiffCompression;
+  VipsForeignTiffPredictor tiffPredictor;
+  bool tiffPyramid;
+  int tiffBitdepth;
+  bool tiffTile;
+  int tiffTileHeight;
+  int tiffTileWidth;
+  double tiffXres;
+  double tiffYres;
+  int heifQuality;
+  VipsForeignHeifCompression heifCompression;
+  int heifSpeed;
+  std::string heifChromaSubsampling;
+  bool heifLossless;
+  std::string err;
+  bool withMetadata;
+  int withMetadataOrientation;
+  std::string withMetadataIcc;
+  std::unique_ptr<double[]> convKernel;
+  int convKernelWidth;
+  int convKernelHeight;
+  double convKernelScale;
+  double convKernelOffset;
+  sharp::InputDescriptor *boolean;
+  VipsOperationBoolean booleanOp;
+  VipsOperationBoolean bandBoolOp;
+  int extractChannel;
+  bool removeAlpha;
+  bool ensureAlpha;
+  VipsInterpretation colourspace;
+  int pageHeight;
+  std::vector<int> delay;
+  int loop;
+  int tileSize;
+  int tileOverlap;
+  VipsForeignDzContainer tileContainer;
+  VipsForeignDzLayout tileLayout;
+  std::string tileFormat;
+  int tileAngle;
+  std::vector<double> tileBackground;
+  int tileSkipBlanks;
+  VipsForeignDzDepth tileDepth;
+  std::string tileId;
+  std::unique_ptr<double[]> recombMatrix;
+
+  PipelineBaton():
+    input(nullptr),
+    bufferOutLength(0),
+    topOffsetPre(-1),
+    topOffsetPost(-1),
+    channels(0),
+    canvas(Canvas::CROP),
+    position(0),
+    resizeBackground{ 0.0, 0.0, 0.0, 255.0 },
+    hasCropOffset(false),
+    cropOffsetLeft(0),
+    cropOffsetTop(0),
+    premultiplied(false),
+    tintA(128.0),
+    tintB(128.0),
+    flatten(false),
+    flattenBackground{ 0.0, 0.0, 0.0 },
+    negate(false),
+    blurSigma(0.0),
+    brightness(1.0),
+    saturation(1.0),
+    hue(0),
+    medianSize(0),
+    sharpenSigma(0.0),
+    sharpenFlat(1.0),
+    sharpenJagged(2.0),
+    threshold(0),
+    thresholdGrayscale(true),
+    trimThreshold(0.0),
+    trimOffsetLeft(0),
+    trimOffsetTop(0),
+    linearA(1.0),
+    linearB(0.0),
+    gamma(0.0),
+    greyscale(false),
+    normalise(false),
+    useExifOrientation(false),
+    angle(0),
+    rotationAngle(0.0),
+    rotationBackground{ 0.0, 0.0, 0.0, 255.0 },
+    flip(false),
+    flop(false),
+    extendTop(0),
+    extendBottom(0),
+    extendLeft(0),
+    extendRight(0),
+    extendBackground{ 0.0, 0.0, 0.0, 255.0 },
+    withoutEnlargement(false),
+    affineMatrix{ 1.0, 0.0, 0.0, 1.0 },
+    affineBackground{ 0.0, 0.0, 0.0, 255.0 },
+    affineIdx(0),
+    affineIdy(0),
+    affineOdx(0),
+    affineOdy(0),
+    affineInterpolator(vips::VInterpolate::new_from_name("bicubic")),
+    jpegQuality(80),
+    jpegProgressive(false),
+    jpegChromaSubsampling("4:2:0"),
+    jpegTrellisQuantisation(false),
+    jpegQuantisationTable(0),
+    jpegOvershootDeringing(false),
+    jpegOptimiseScans(false),
+    jpegOptimiseCoding(true),
+    pngProgressive(false),
+    pngCompressionLevel(6),
+    pngAdaptiveFiltering(false),
+    pngPalette(false),
+    pngQuality(100),
+    pngColours(256),
+    pngDither(1.0),
+    webpQuality(80),
+    webpAlphaQuality(100),
+    webpNearLossless(false),
+    webpLossless(false),
+    webpSmartSubsample(false),
+    webpReductionEffort(4),
+    tiffQuality(80),
+    tiffCompression(VIPS_FOREIGN_TIFF_COMPRESSION_JPEG),
+    tiffPredictor(VIPS_FOREIGN_TIFF_PREDICTOR_HORIZONTAL),
+    tiffPyramid(false),
+    tiffBitdepth(8),
+    tiffTile(false),
+    tiffTileHeight(256),
+    tiffTileWidth(256),
+    tiffXres(1.0),
+    tiffYres(1.0),
+    heifQuality(50),
+    heifCompression(VIPS_FOREIGN_HEIF_COMPRESSION_AV1),
+    heifSpeed(5),
+    heifChromaSubsampling("4:2:0"),
+    heifLossless(false),
+    withMetadata(false),
+    withMetadataOrientation(-1),
+    convKernelWidth(0),
+    convKernelHeight(0),
+    convKernelScale(0.0),
+    convKernelOffset(0.0),
+    boolean(nullptr),
+    booleanOp(VIPS_OPERATION_BOOLEAN_LAST),
+    bandBoolOp(VIPS_OPERATION_BOOLEAN_LAST),
+    extractChannel(-1),
+    removeAlpha(false),
+    ensureAlpha(false),
+    colourspace(VIPS_INTERPRETATION_LAST),
+    pageHeight(0),
+    delay{-1},
+    loop(-1),
+    tileSize(256),
+    tileOverlap(0),
+    tileContainer(VIPS_FOREIGN_DZ_CONTAINER_FS),
+    tileLayout(VIPS_FOREIGN_DZ_LAYOUT_DZ),
+    tileAngle(0),
+    tileBackground{ 255.0, 255.0, 255.0, 255.0 },
+    tileSkipBlanks(-1),
+    tileDepth(VIPS_FOREIGN_DZ_DEPTH_LAST) {}
+};
+
+#endif  // SRC_PIPELINE_H_

src/sharp.cc

@@ -1,515 +1,52 @@
-#include <node.h>
-#include <node_buffer.h>
-#include <math.h>
-#include <string>
-#include <string.h>
-#include <vips/vips.h>
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
 
-#include "nan.h"
+#include <napi.h>
+#include <vips/vips8>
 
-using namespace v8;
-using namespace node;
+#include "common.h"
+#include "metadata.h"
+#include "pipeline.h"
+#include "utilities.h"
+#include "stats.h"
 
-struct resize_baton {
-  std::string file_in;
-  void* buffer_in;
-  size_t buffer_in_len;
-  std::string file_out;
-  void* buffer_out;
-  size_t buffer_out_len;
-  int width;
-  int height;
-  bool crop;
-  bool max;
-  VipsExtend extend;
-  bool sharpen;
-  std::string interpolator;
-  bool progressive;
-  bool without_enlargement;
-  VipsAccess access_method;
-  int quality;
-  int compressionLevel;
-  int angle;
-  std::string err;
-
-  resize_baton():
-    buffer_in_len(0),
-    buffer_out_len(0),
-    crop(false),
-    max(false),
-    sharpen(false),
-    progressive(false),
-    without_enlargement(false) {}
-};
-
-typedef enum {
-  JPEG,
-  PNG,
-  WEBP,
-  TIFF,
-  MAGICK
-} ImageType;
-
-unsigned char const MARKER_JPEG[] = {0xff, 0xd8};
-unsigned char const MARKER_PNG[] = {0x89, 0x50};
-unsigned char const MARKER_WEBP[] = {0x52, 0x49};
-
-static bool ends_with(std::string const &str, std::string const &end) {
-  return str.length() >= end.length() && 0 == str.compare(str.length() - end.length(), end.length(), end);
+static void* sharp_vips_init(void*) {
+  g_setenv("VIPS_MIN_STACK_SIZE", "2m", FALSE);
+  vips_init("sharp");
+  return nullptr;
 }
 
-static bool is_jpeg(std::string const &str) {
-  return ends_with(str, ".jpg") || ends_with(str, ".jpeg") || ends_with(str, ".JPG") || ends_with(str, ".JPEG");
+Napi::Object init(Napi::Env env, Napi::Object exports) {
+  static GOnce sharp_vips_init_once = G_ONCE_INIT;
+  g_once(&sharp_vips_init_once, static_cast<GThreadFunc>(sharp_vips_init), nullptr);
+
+  g_log_set_handler("VIPS", static_cast<GLogLevelFlags>(G_LOG_LEVEL_WARNING),
+    static_cast<GLogFunc>(sharp::VipsWarningCallback), nullptr);
+
+  // Methods available to JavaScript
+  exports.Set("metadata", Napi::Function::New(env, metadata));
+  exports.Set("pipeline", Napi::Function::New(env, pipeline));
+  exports.Set("cache", Napi::Function::New(env, cache));
+  exports.Set("concurrency", Napi::Function::New(env, concurrency));
+  exports.Set("counters", Napi::Function::New(env, counters));
+  exports.Set("simd", Napi::Function::New(env, simd));
+  exports.Set("libvipsVersion", Napi::Function::New(env, libvipsVersion));
+  exports.Set("format", Napi::Function::New(env, format));
+  exports.Set("_maxColourDistance", Napi::Function::New(env, _maxColourDistance));
+  exports.Set("_isUsingJemalloc", Napi::Function::New(env, _isUsingJemalloc));
+  exports.Set("stats", Napi::Function::New(env, stats));
+  return exports;
 }
 
-static bool is_png(std::string const &str) {
-  return ends_with(str, ".png") || ends_with(str, ".PNG");
-}
-
-static bool is_webp(std::string const &str) {
-  return ends_with(str, ".webp") || ends_with(str, ".WEBP");
-}
-
-static bool is_tiff(std::string const &str) {
-  return ends_with(str, ".tif") || ends_with(str, ".tiff") || ends_with(str, ".TIF") || ends_with(str, ".TIFF");
-}
-
-static void resize_error(resize_baton *baton, VipsImage *unref) {
-  (baton->err).append(vips_error_buffer());
-  vips_error_clear();
-  g_object_unref(unref);
-  vips_thread_shutdown();
-  return;
-}
-
-/*
-  Calculate the angle of rotation for the output image.
-  In order of priority:
-   1. Use explicitly requested angle (supports 90, 180, 270)
-   2. Use input image EXIF Orientation header (does not support mirroring)
-   3. Otherwise default to zero, i.e. no rotation
-*/
-static VipsAngle calc_rotation(int const angle, VipsImage const *input) {
-  VipsAngle rotate = VIPS_ANGLE_0;
-  if (angle == -1) {
-    const char *exif;
-    if (!vips_image_get_string(input, "exif-ifd0-Orientation", &exif)) {
-      if (exif[0] == 0x36) { // "6"
-        rotate = VIPS_ANGLE_90;
-      } else if (exif[0] == 0x33) { // "3"
-        rotate = VIPS_ANGLE_180;
-      } else if (exif[0] == 0x38) { // "8"
-        rotate = VIPS_ANGLE_270;
-      }
-    }
-  } else {
-    if (angle == 90) {
-      rotate = VIPS_ANGLE_90;
-    } else if (angle == 180) {
-      rotate = VIPS_ANGLE_180;
-    } else if (angle == 270) {
-      rotate = VIPS_ANGLE_270;
-    }
-  }
-  return rotate;
-}
-
-class ResizeWorker : public NanAsyncWorker {
- public:
-  ResizeWorker(NanCallback *callback, resize_baton *baton)
-    : NanAsyncWorker(callback), baton(baton) {}
-  ~ResizeWorker() {}
-
-  void Execute () {
-    // Input
-    ImageType inputImageType = JPEG;
-    VipsImage *in = vips_image_new();
-    if (baton->buffer_in_len > 1) {
-      if (memcmp(MARKER_JPEG, baton->buffer_in, 2) == 0) {
-        if (vips_jpegload_buffer(baton->buffer_in, baton->buffer_in_len, &in, "access", baton->access_method, NULL)) {
-          return resize_error(baton, in);
-        }
-      } else if(memcmp(MARKER_PNG, baton->buffer_in, 2) == 0) {
-        inputImageType = PNG;
-        if (vips_pngload_buffer(baton->buffer_in, baton->buffer_in_len, &in, "access", baton->access_method, NULL)) {
-          return resize_error(baton, in);
-        }
-      } else if(memcmp(MARKER_WEBP, baton->buffer_in, 2) == 0) {
-        inputImageType = WEBP;
-        if (vips_webpload_buffer(baton->buffer_in, baton->buffer_in_len, &in, "access", baton->access_method, NULL)) {
-          return resize_error(baton, in);
-        }
-      } else {
-        resize_error(baton, in);
-        (baton->err).append("Unsupported input buffer");
-        return;
-      }
-    } else if (vips_foreign_is_a("jpegload", baton->file_in.c_str())) {
-      if (vips_jpegload((baton->file_in).c_str(), &in, "access", baton->access_method, NULL)) {
-        return resize_error(baton, in);
-      }
-    } else if (vips_foreign_is_a("pngload", baton->file_in.c_str())) {
-      inputImageType = PNG;
-      if (vips_pngload((baton->file_in).c_str(), &in, "access", baton->access_method, NULL)) {
-        return resize_error(baton, in);
-      }
-    } else if (vips_foreign_is_a("webpload", baton->file_in.c_str())) {
-      inputImageType = WEBP;
-      if (vips_webpload((baton->file_in).c_str(), &in, "access", baton->access_method, NULL)) {
-        return resize_error(baton, in);
-      }
-    } else if (vips_foreign_is_a("tiffload", baton->file_in.c_str())) {
-      inputImageType = TIFF;
-      if (vips_tiffload((baton->file_in).c_str(), &in, "access", baton->access_method, NULL)) {
-        return resize_error(baton, in);
-      }
-    } else if(vips_foreign_is_a("magickload", (baton->file_in).c_str())) {
-      inputImageType = MAGICK;
-      if (vips_magickload((baton->file_in).c_str(), &in, "access", baton->access_method, NULL)) {
-        return resize_error(baton, in);
-      }
-    } else {
-      resize_error(baton, in);
-      (baton->err).append("Unsupported input file " + baton->file_in);
-      return;
-    }
-
-    // Get input image width and height
-    int inputWidth = in->Xsize;
-    int inputHeight = in->Ysize;
-
-    // Calculate angle of rotation, to be carried out later
-    VipsAngle rotation = calc_rotation(baton->angle, in);
-    if (rotation == VIPS_ANGLE_90 || rotation == VIPS_ANGLE_270) {
-      // Swap input output width and height when rotating by 90 or 270 degrees
-      int swap = inputWidth;
-      inputWidth = inputHeight;
-      inputHeight = swap;
-    }
-
-    // Scaling calculations
-    double factor;
-    if (baton->width > 0 && baton->height > 0) {
-      // Fixed width and height
-      double xfactor = static_cast<double>(inputWidth) / static_cast<double>(baton->width);
-      double yfactor = static_cast<double>(inputHeight) / static_cast<double>(baton->height);
-      factor = baton->crop ? std::min(xfactor, yfactor) : std::max(xfactor, yfactor);
-      // if max is set, we need to compute the real size of the thumb image
-      if (baton->max) {
-        if (xfactor > yfactor) {
-          baton->height = round(static_cast<double>(inputHeight) / xfactor);
-        } else {
-          baton->width = round(static_cast<double>(inputWidth) / yfactor);
-        }
-      }
-    } else if (baton->width > 0) {
-      // Fixed width, auto height
-      factor = static_cast<double>(inputWidth) / static_cast<double>(baton->width);
-      baton->height = floor(static_cast<double>(inputHeight) / factor);
-    } else if (baton->height > 0) {
-      // Fixed height, auto width
-      factor = static_cast<double>(inputHeight) / static_cast<double>(baton->height);
-      baton->width = floor(static_cast<double>(inputWidth) / factor);
-    } else {
-      // Identity transform
-      factor = 1;
-      baton->width = inputWidth;
-      baton->height = inputHeight;
-    }
-    int shrink = floor(factor);
-    if (shrink < 1) {
-      shrink = 1;
-    }
-    double residual = static_cast<double>(shrink) / factor;
-
-    // Do not enlarge the output if the input width *or* height are already less than the required dimensions
-    if (baton->without_enlargement) {
-      if (inputWidth < baton->width || inputHeight < baton->height) {
-        factor = 1;
-        shrink = 1;
-        residual = 0;
-        baton->width = inputWidth;
-        baton->height = inputHeight;
-      }
-    }
-
-    // Try to use libjpeg shrink-on-load
-    int shrink_on_load = 1;
-    if (inputImageType == JPEG) {
-      if (shrink >= 8) {
-        factor = factor / 8;
-        shrink_on_load = 8;
-      } else if (shrink >= 4) {
-        factor = factor / 4;
-        shrink_on_load = 4;
-      } else if (shrink >= 2) {
-        factor = factor / 2;
-        shrink_on_load = 2;
-      }
-    }
-    VipsImage *shrunk_on_load = vips_image_new();
-    if (shrink_on_load > 1) {
-      // Recalculate integral shrink and double residual
-      factor = std::max(factor, 1.0);
-      shrink = floor(factor);
-      residual = static_cast<double>(shrink) / factor;
-      // Reload input using shrink-on-load
-      if (baton->buffer_in_len > 1) {
-        if (vips_jpegload_buffer(baton->buffer_in, baton->buffer_in_len, &shrunk_on_load, "shrink", shrink_on_load, NULL)) {
-          return resize_error(baton, in);
-        }
-      } else {
-        if (vips_jpegload((baton->file_in).c_str(), &shrunk_on_load, "shrink", shrink_on_load, NULL)) {
-          return resize_error(baton, in);
-        }
-      }
-    } else {
-      vips_copy(in, &shrunk_on_load, NULL);
-    }
-    g_object_unref(in);
-
-    VipsImage *shrunk = vips_image_new();
-    if (shrink > 1) {
-      // Use vips_shrink with the integral reduction
-      if (vips_shrink(shrunk_on_load, &shrunk, shrink, shrink, NULL)) {
-        return resize_error(baton, shrunk_on_load);
-      }
-      // Recalculate residual float based on dimensions of required vs shrunk images
-      double shrunkWidth = shrunk->Xsize;
-      double shrunkHeight = shrunk->Ysize;
-      if (rotation == VIPS_ANGLE_90 || rotation == VIPS_ANGLE_270) {
-        // Swap input output width and height when rotating by 90 or 270 degrees
-        int swap = shrunkWidth;
-        shrunkWidth = shrunkHeight;
-        shrunkHeight = swap;
-      }
-      double residualx = static_cast<double>(baton->width) / static_cast<double>(shrunkWidth);
-      double residualy = static_cast<double>(baton->height) / static_cast<double>(shrunkHeight);
-      if (baton->crop || baton->max) {
-        residual = std::max(residualx, residualy);
-      } else {
-        residual = std::min(residualx, residualy);
-      }
-    } else {
-      vips_copy(shrunk_on_load, &shrunk, NULL);
-    }
-    g_object_unref(shrunk_on_load);
-
-    // Use vips_affine with the remaining float part
-    VipsImage *affined = vips_image_new();
-    if (residual != 0) {
-      // Create interpolator - "bilinear" (default), "bicubic" or "nohalo"
-      VipsInterpolate *interpolator = vips_interpolate_new(baton->interpolator.c_str());
-      // Perform affine transformation
-      if (vips_affine(shrunk, &affined, residual, 0, 0, residual, "interpolate", interpolator, NULL)) {
-        g_object_unref(interpolator);
-        return resize_error(baton, shrunk);
-      }
-      g_object_unref(interpolator);
-    } else {
-      vips_copy(shrunk, &affined, NULL);
-    }
-    g_object_unref(shrunk);
-
-    // Rotate
-    VipsImage *rotated = vips_image_new();
-    if (rotation != VIPS_ANGLE_0) {
-      if (vips_rot(affined, &rotated, rotation, NULL)) {
-        return resize_error(baton, affined);
-      }
-    } else {
-      vips_copy(affined, &rotated, NULL);
-    }
-    g_object_unref(affined);
-
-    // Crop/embed
-    VipsImage *canvased = vips_image_new();
-    if (rotated->Xsize != baton->width || rotated->Ysize != baton->height) {
-      if (baton->crop || baton->max) {
-        // Crop/max
-        int width = std::min(rotated->Xsize, baton->width);
-        int height = std::min(rotated->Ysize, baton->height);
-        int left = (rotated->Xsize - width + 1) / 2;
-        int top = (rotated->Ysize - height + 1) / 2;
-        if (vips_extract_area(rotated, &canvased, left, top, width, height, NULL)) {
-          return resize_error(baton, rotated);
-        }
-      } else {
-        // Embed
-        int left = (baton->width - rotated->Xsize) / 2;
-        int top = (baton->height - rotated->Ysize) / 2;
-        if (vips_embed(rotated, &canvased, left, top, baton->width, baton->height, "extend", baton->extend, NULL)) {
-          return resize_error(baton, rotated);
-        }
-      }
-    } else {
-      vips_copy(rotated, &canvased, NULL);
-    }
-    g_object_unref(rotated);
-
-    // Mild sharpen
-    VipsImage *sharpened = vips_image_new();
-    if (baton->sharpen) {
-      VipsImage *sharpen = vips_image_new_matrixv(3, 3,
-        -1.0, -1.0, -1.0,
-        -1.0, 32.0, -1.0,
-        -1.0, -1.0, -1.0);
-      vips_image_set_double(sharpen, "scale", 24);
-      if (vips_conv(canvased, &sharpened, sharpen, NULL)) {
-        g_object_unref(sharpen);
-        return resize_error(baton, canvased);
-      }
-      g_object_unref(sharpen);
-    } else {
-      vips_copy(canvased, &sharpened, NULL);
-    }
-    g_object_unref(canvased);
-
-    // Always convert to sRGB colour space
-    VipsImage *colourspaced = vips_image_new();
-    vips_colourspace(sharpened, &colourspaced, VIPS_INTERPRETATION_sRGB, NULL);
-    g_object_unref(sharpened);
-
-    // Output
-    if (baton->file_out == "__jpeg" || (baton->file_out == "__input" && inputImageType == JPEG)) {
-      // Write JPEG to buffer
-      if (vips_jpegsave_buffer(colourspaced, &baton->buffer_out, &baton->buffer_out_len, "strip", TRUE, "Q", baton->quality, "optimize_coding", TRUE, "interlace", baton->progressive, NULL)) {
-        return resize_error(baton, colourspaced);
-      }
-    } else if (baton->file_out == "__png" || (baton->file_out == "__input" && inputImageType == PNG)) {
-      // Write PNG to buffer
-      if (vips_pngsave_buffer(colourspaced, &baton->buffer_out, &baton->buffer_out_len, "strip", TRUE, "compression", baton->compressionLevel, "interlace", baton->progressive, NULL)) {
-        return resize_error(baton, colourspaced);
-      }
-    } else if (baton->file_out == "__webp" || (baton->file_out == "__input" && inputImageType == WEBP)) {
-      // Write WEBP to buffer
-      if (vips_webpsave_buffer(colourspaced, &baton->buffer_out, &baton->buffer_out_len, "strip", TRUE, "Q", baton->quality, NULL)) {
-        return resize_error(baton, colourspaced);
-      }
-    } else if (is_jpeg(baton->file_out))  {
-      // Write JPEG to file
-      if (vips_jpegsave(colourspaced, baton->file_out.c_str(), "strip", TRUE, "Q", baton->quality, "optimize_coding", TRUE, "interlace", baton->progressive, NULL)) {
-        return resize_error(baton, colourspaced);
-      }
-    } else if (is_png(baton->file_out)) {
-      // Write PNG to file
-      if (vips_pngsave(colourspaced, baton->file_out.c_str(), "strip", TRUE, "compression", baton->compressionLevel, "interlace", baton->progressive, NULL)) {
-        return resize_error(baton, colourspaced);
-      }
-    } else if (is_webp(baton->file_out)) {
-      // Write WEBP to file
-      if (vips_webpsave(colourspaced, baton->file_out.c_str(), "strip", TRUE, "Q", baton->quality, NULL)) {
-        return resize_error(baton, colourspaced);
-      }
-    } else if (is_tiff(baton->file_out)) {
-      // Write TIFF to file
-      if (vips_tiffsave(colourspaced, baton->file_out.c_str(), "strip", TRUE, "compression", VIPS_FOREIGN_TIFF_COMPRESSION_JPEG, "Q", baton->quality, NULL)) {
-        return resize_error(baton, colourspaced);
-      }
-    } else {
-      (baton->err).append("Unsupported output " + baton->file_out);
-    }
-    g_object_unref(colourspaced);
-    vips_thread_shutdown();
-  }
-
-  void HandleOKCallback () {
-    NanScope();
-
-    Handle<Value> argv[2] = { NanNull(), NanNull() };
-    if (!baton->err.empty()) {
-      // Error
-      argv[0] = NanNew<String>(baton->err.data(), baton->err.size());
-    } else if (baton->buffer_out_len > 0) {
-      // Buffer
-      argv[1] = NanNewBufferHandle((char *)baton->buffer_out, baton->buffer_out_len);
-      g_free(baton->buffer_out);
-    }
-    delete baton;
-    callback->Call(2, argv);
-  }
-
- private:
-  resize_baton* baton;
-};
-
-/*
-  resize(options, output, callback)
-*/
-NAN_METHOD(resize) {
-  NanScope();
-
-  // V8 objects are converted to non-V8 types held in the baton struct
-  resize_baton *baton = new resize_baton;
-  Local<Object> options = args[0]->ToObject();
-
-  // Input filename
-  baton->file_in = *String::Utf8Value(options->Get(NanNew<String>("fileIn"))->ToString());
-  // Input Buffer object
-  if (options->Get(NanNew<String>("bufferIn"))->IsObject()) {
-    Local<Object> buffer = options->Get(NanNew<String>("bufferIn"))->ToObject();
-    baton->buffer_in_len = Buffer::Length(buffer);
-    baton->buffer_in = Buffer::Data(buffer);
-  }
-  // Output image dimensions
-  baton->width = options->Get(NanNew<String>("width"))->Int32Value();
-  baton->height = options->Get(NanNew<String>("height"))->Int32Value();
-  // Canvas options
-  Local<String> canvas = options->Get(NanNew<String>("canvas"))->ToString();
-  if (canvas->Equals(NanNew<String>("c"))) {
-    baton->crop = true;
-  } else if (canvas->Equals(NanNew<String>("w"))) {
-    baton->extend = VIPS_EXTEND_WHITE;
-  } else if (canvas->Equals(NanNew<String>("b"))) {
-    baton->extend = VIPS_EXTEND_BLACK;
-  } else if (canvas->Equals(NanNew<String>("m"))) {
-    baton->max = true;
-  }
-  // Other options
-  baton->sharpen = options->Get(NanNew<String>("sharpen"))->BooleanValue();
-  baton->interpolator = *String::Utf8Value(options->Get(NanNew<String>("interpolator"))->ToString());
-  baton->progressive = options->Get(NanNew<String>("progressive"))->BooleanValue();
-  baton->without_enlargement = options->Get(NanNew<String>("withoutEnlargement"))->BooleanValue();
-  baton->access_method = options->Get(NanNew<String>("sequentialRead"))->BooleanValue() ? VIPS_ACCESS_SEQUENTIAL : VIPS_ACCESS_RANDOM;
-  baton->quality = options->Get(NanNew<String>("quality"))->Int32Value();
-  baton->compressionLevel = options->Get(NanNew<String>("compressionLevel"))->Int32Value();
-  baton->angle = options->Get(NanNew<String>("angle"))->Int32Value();
-  // Output filename or __format for Buffer
-  baton->file_out = *String::Utf8Value(args[1]->ToString());
-
-  // Join queue for worker thread
-  NanCallback *callback = new NanCallback(args[2].As<v8::Function>());
-  NanAsyncQueueWorker(new ResizeWorker(callback, baton));
-  NanReturnUndefined();
-}
-
-NAN_METHOD(cache) {
-  NanScope();
-
-  // Set cache limit
-  if (args[0]->IsInt32()) {
-    vips_cache_set_max_mem(args[0]->Int32Value() * 1048576);
-  }
-
-  // Get cache statistics
-  Local<Object> cache = NanNew<Object>();
-  cache->Set(NanNew<String>("current"), NanNew<Number>(vips_tracked_get_mem() / 1048576));
-  cache->Set(NanNew<String>("high"), NanNew<Number>(vips_tracked_get_mem_highwater() / 1048576));
-  cache->Set(NanNew<String>("limit"), NanNew<Number>(vips_cache_get_max_mem() / 1048576));
-  NanReturnValue(cache);
-}
-
-static void at_exit(void* arg) {
-  NanScope();
-  vips_shutdown();
-}
-
-extern "C" void init(Handle<Object> target) {
-  NanScope();
-  vips_init("");
-  AtExit(at_exit);
-  NODE_SET_METHOD(target, "resize", resize);
-  NODE_SET_METHOD(target, "cache", cache);
-}
-
-NODE_MODULE(sharp, init)
+NODE_API_MODULE(sharp, init)

src/stats.cc

@@ -0,0 +1,193 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <numeric>
+#include <vector>
+#include <iostream>
+
+#include <napi.h>
+#include <vips/vips8>
+
+#include "common.h"
+#include "stats.h"
+
+class StatsWorker : public Napi::AsyncWorker {
+ public:
+  StatsWorker(Napi::Function callback, StatsBaton *baton, Napi::Function debuglog) :
+    Napi::AsyncWorker(callback), baton(baton), debuglog(Napi::Persistent(debuglog)) {}
+  ~StatsWorker() {}
+
+  const int STAT_MIN_INDEX = 0;
+  const int STAT_MAX_INDEX = 1;
+  const int STAT_SUM_INDEX = 2;
+  const int STAT_SQ_SUM_INDEX = 3;
+  const int STAT_MEAN_INDEX = 4;
+  const int STAT_STDEV_INDEX = 5;
+  const int STAT_MINX_INDEX = 6;
+  const int STAT_MINY_INDEX = 7;
+  const int STAT_MAXX_INDEX = 8;
+  const int STAT_MAXY_INDEX = 9;
+
+  void Execute() {
+    // Decrement queued task counter
+    g_atomic_int_dec_and_test(&sharp::counterQueue);
+
+    vips::VImage image;
+    sharp::ImageType imageType = sharp::ImageType::UNKNOWN;
+    try {
+      std::tie(image, imageType) = OpenInput(baton->input);
+    } catch (vips::VError const &err) {
+      (baton->err).append(err.what());
+    }
+    if (imageType != sharp::ImageType::UNKNOWN) {
+      try {
+        vips::VImage stats = image.stats();
+        int const bands = image.bands();
+        for (int b = 1; b <= bands; b++) {
+          ChannelStats cStats(
+            static_cast<int>(stats.getpoint(STAT_MIN_INDEX, b).front()),
+            static_cast<int>(stats.getpoint(STAT_MAX_INDEX, b).front()),
+            stats.getpoint(STAT_SUM_INDEX, b).front(),
+            stats.getpoint(STAT_SQ_SUM_INDEX, b).front(),
+            stats.getpoint(STAT_MEAN_INDEX, b).front(),
+            stats.getpoint(STAT_STDEV_INDEX, b).front(),
+            static_cast<int>(stats.getpoint(STAT_MINX_INDEX, b).front()),
+            static_cast<int>(stats.getpoint(STAT_MINY_INDEX, b).front()),
+            static_cast<int>(stats.getpoint(STAT_MAXX_INDEX, b).front()),
+            static_cast<int>(stats.getpoint(STAT_MAXY_INDEX, b).front()));
+          baton->channelStats.push_back(cStats);
+        }
+        // Image is not opaque when alpha layer is present and contains a non-mamixa value
+        if (sharp::HasAlpha(image)) {
+          double const minAlpha = static_cast<double>(stats.getpoint(STAT_MIN_INDEX, bands).front());
+          if (minAlpha != sharp::MaximumImageAlpha(image.interpretation())) {
+            baton->isOpaque = false;
+          }
+        }
+        // Convert to greyscale
+        vips::VImage greyscale = image.colourspace(VIPS_INTERPRETATION_B_W)[0];
+        // Estimate entropy via histogram of greyscale value frequency
+        baton->entropy = std::abs(greyscale.hist_find().hist_entropy());
+        // Estimate sharpness via standard deviation of greyscale laplacian
+        if (image.width() > 1 || image.height() > 1) {
+          VImage laplacian = VImage::new_matrixv(3, 3,
+            0.0,  1.0, 0.0,
+            1.0, -4.0, 1.0,
+            0.0,  1.0, 0.0);
+          laplacian.set("scale", 9.0);
+          baton->sharpness = greyscale.conv(laplacian).deviate();
+        }
+        // Most dominant sRGB colour via 4096-bin 3D histogram
+        vips::VImage hist = sharp::RemoveAlpha(image)
+          .colourspace(VIPS_INTERPRETATION_sRGB)
+          .hist_find_ndim(VImage::option()->set("bins", 16));
+        std::complex<double> maxpos = hist.maxpos();
+        int const dx = static_cast<int>(std::real(maxpos));
+        int const dy = static_cast<int>(std::imag(maxpos));
+        std::vector<double> pel = hist(dx, dy);
+        int const dz = std::distance(pel.begin(), std::find(pel.begin(), pel.end(), hist.max()));
+        baton->dominantRed = dx * 16 + 8;
+        baton->dominantGreen = dy * 16 + 8;
+        baton->dominantBlue = dz * 16 + 8;
+      } catch (vips::VError const &err) {
+        (baton->err).append(err.what());
+      }
+    }
+
+    // Clean up
+    vips_error_clear();
+    vips_thread_shutdown();
+  }
+
+  void OnOK() {
+    Napi::Env env = Env();
+    Napi::HandleScope scope(env);
+
+    // Handle warnings
+    std::string warning = sharp::VipsWarningPop();
+    while (!warning.empty()) {
+      debuglog.Call({ Napi::String::New(env, warning) });
+      warning = sharp::VipsWarningPop();
+    }
+
+    if (baton->err.empty()) {
+      // Stats Object
+      Napi::Object info = Napi::Object::New(env);
+      Napi::Array channels = Napi::Array::New(env);
+
+      std::vector<ChannelStats>::iterator it;
+      int i = 0;
+      for (it = baton->channelStats.begin(); it < baton->channelStats.end(); it++, i++) {
+        Napi::Object channelStat = Napi::Object::New(env);
+        channelStat.Set("min", it->min);
+        channelStat.Set("max", it->max);
+        channelStat.Set("sum", it->sum);
+        channelStat.Set("squaresSum", it->squaresSum);
+        channelStat.Set("mean", it->mean);
+        channelStat.Set("stdev", it->stdev);
+        channelStat.Set("minX", it->minX);
+        channelStat.Set("minY", it->minY);
+        channelStat.Set("maxX", it->maxX);
+        channelStat.Set("maxY", it->maxY);
+        channels.Set(i, channelStat);
+      }
+
+      info.Set("channels", channels);
+      info.Set("isOpaque", baton->isOpaque);
+      info.Set("entropy", baton->entropy);
+      info.Set("sharpness", baton->sharpness);
+      Napi::Object dominant = Napi::Object::New(env);
+      dominant.Set("r", baton->dominantRed);
+      dominant.Set("g", baton->dominantGreen);
+      dominant.Set("b", baton->dominantBlue);
+      info.Set("dominant", dominant);
+      Callback().MakeCallback(Receiver().Value(), { env.Null(), info });
+    } else {
+      Callback().MakeCallback(Receiver().Value(), { Napi::Error::New(env, baton->err).Value() });
+    }
+
+    delete baton->input;
+    delete baton;
+  }
+
+ private:
+  StatsBaton* baton;
+  Napi::FunctionReference debuglog;
+};
+
+/*
+  stats(options, callback)
+*/
+Napi::Value stats(const Napi::CallbackInfo& info) {
+  // V8 objects are converted to non-V8 types held in the baton struct
+  StatsBaton *baton = new StatsBaton;
+  Napi::Object options = info[0].As<Napi::Object>();
+
+  // Input
+  baton->input = sharp::CreateInputDescriptor(options.Get("input").As<Napi::Object>());
+
+  // Function to notify of libvips warnings
+  Napi::Function debuglog = options.Get("debuglog").As<Napi::Function>();
+
+  // Join queue for worker thread
+  Napi::Function callback = info[1].As<Napi::Function>();
+  StatsWorker *worker = new StatsWorker(callback, baton, debuglog);
+  worker->Receiver().Set("options", options);
+  worker->Queue();
+
+  // Increment queued task counter
+  g_atomic_int_inc(&sharp::counterQueue);
+
+  return info.Env().Undefined();
+}

src/stats.h

@@ -0,0 +1,70 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef SRC_STATS_H_
+#define SRC_STATS_H_
+
+#include <string>
+#include <napi.h>
+
+#include "./common.h"
+
+struct ChannelStats {
+  // stats per channel
+  int min;
+  int max;
+  double sum;
+  double squaresSum;
+  double mean;
+  double stdev;
+  int minX;
+  int minY;
+  int maxX;
+  int maxY;
+
+  ChannelStats(int minVal, int maxVal, double sumVal, double squaresSumVal,
+    double meanVal, double stdevVal, int minXVal, int minYVal, int maxXVal, int maxYVal):
+    min(minVal), max(maxVal), sum(sumVal), squaresSum(squaresSumVal),
+    mean(meanVal), stdev(stdevVal), minX(minXVal), minY(minYVal), maxX(maxXVal), maxY(maxYVal) {}
+};
+
+struct StatsBaton {
+  // Input
+  sharp::InputDescriptor *input;
+
+  // Output
+  std::vector<ChannelStats> channelStats;
+  bool isOpaque;
+  double entropy;
+  double sharpness;
+  int dominantRed;
+  int dominantGreen;
+  int dominantBlue;
+
+  std::string err;
+
+  StatsBaton():
+    input(nullptr),
+    isOpaque(true),
+    entropy(0.0),
+    sharpness(0.0),
+    dominantRed(0),
+    dominantGreen(0),
+    dominantBlue(0)
+    {}
+};
+
+Napi::Value stats(const Napi::CallbackInfo& info);
+
+#endif  // SRC_STATS_H_

src/utilities.cc

@@ -0,0 +1,243 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <cmath>
+#include <string>
+
+#include <napi.h>
+#include <vips/vips8>
+#include <vips/vector.h>
+
+#include "common.h"
+#include "operations.h"
+#include "utilities.h"
+
+/*
+  Get and set cache limits
+*/
+Napi::Value cache(const Napi::CallbackInfo& info) {
+  Napi::Env env = info.Env();
+
+  // Set memory limit
+  if (info[0].IsNumber()) {
+    vips_cache_set_max_mem(info[0].As<Napi::Number>().Int32Value() * 1048576);
+  }
+  // Set file limit
+  if (info[1].IsNumber()) {
+    vips_cache_set_max_files(info[1].As<Napi::Number>().Int32Value());
+  }
+  // Set items limit
+  if (info[2].IsNumber()) {
+    vips_cache_set_max(info[2].As<Napi::Number>().Int32Value());
+  }
+
+  // Get memory stats
+  Napi::Object memory = Napi::Object::New(env);
+  memory.Set("current", round(vips_tracked_get_mem() / 1048576));
+  memory.Set("high", round(vips_tracked_get_mem_highwater() / 1048576));
+  memory.Set("max", round(vips_cache_get_max_mem() / 1048576));
+  // Get file stats
+  Napi::Object files = Napi::Object::New(env);
+  files.Set("current", vips_tracked_get_files());
+  files.Set("max", vips_cache_get_max_files());
+
+  // Get item stats
+  Napi::Object items = Napi::Object::New(env);
+  items.Set("current", vips_cache_get_size());
+  items.Set("max", vips_cache_get_max());
+
+  Napi::Object cache = Napi::Object::New(env);
+  cache.Set("memory", memory);
+  cache.Set("files", files);
+  cache.Set("items", items);
+  return cache;
+}
+
+/*
+  Get and set size of thread pool
+*/
+Napi::Value concurrency(const Napi::CallbackInfo& info) {
+  // Set concurrency
+  if (info[0].IsNumber()) {
+    vips_concurrency_set(info[0].As<Napi::Number>().Int32Value());
+  }
+  // Get concurrency
+  return Napi::Number::New(info.Env(), vips_concurrency_get());
+}
+
+/*
+  Get internal counters (queued tasks, processing tasks)
+*/
+Napi::Value counters(const Napi::CallbackInfo& info) {
+  Napi::Object counters = Napi::Object::New(info.Env());
+  counters.Set("queue", sharp::counterQueue);
+  counters.Set("process", sharp::counterProcess);
+  return counters;
+}
+
+/*
+  Get and set use of SIMD vector unit instructions
+*/
+Napi::Value simd(const Napi::CallbackInfo& info) {
+  // Set state
+  if (info[0].IsBoolean()) {
+    vips_vector_set_enabled(info[0].As<Napi::Boolean>().Value());
+  }
+  // Get state
+  return Napi::Boolean::New(info.Env(), vips_vector_isenabled());
+}
+
+/*
+  Get libvips version
+*/
+Napi::Value libvipsVersion(const Napi::CallbackInfo& info) {
+  char version[9];
+  g_snprintf(version, sizeof(version), "%d.%d.%d", vips_version(0), vips_version(1), vips_version(2));
+  return Napi::String::New(info.Env(), version);
+}
+
+/*
+  Get available input/output file/buffer/stream formats
+*/
+Napi::Value format(const Napi::CallbackInfo& info) {
+  Napi::Env env = info.Env();
+  Napi::Object format = Napi::Object::New(env);
+  for (std::string const f : {
+    "jpeg", "png", "webp", "tiff", "magick", "openslide", "dz",
+    "ppm", "fits", "gif", "svg", "heif", "pdf", "vips"
+  }) {
+    // Input
+    Napi::Boolean hasInputFile =
+      Napi::Boolean::New(env, vips_type_find("VipsOperation", (f + "load").c_str()));
+    Napi::Boolean hasInputBuffer =
+      Napi::Boolean::New(env, vips_type_find("VipsOperation", (f + "load_buffer").c_str()));
+    Napi::Object input = Napi::Object::New(env);
+    input.Set("file", hasInputFile);
+    input.Set("buffer", hasInputBuffer);
+    input.Set("stream", hasInputBuffer);
+    // Output
+    Napi::Boolean hasOutputFile =
+      Napi::Boolean::New(env, vips_type_find("VipsOperation", (f + "save").c_str()));
+    Napi::Boolean hasOutputBuffer =
+      Napi::Boolean::New(env, vips_type_find("VipsOperation", (f + "save_buffer").c_str()));
+    Napi::Object output = Napi::Object::New(env);
+    output.Set("file", hasOutputFile);
+    output.Set("buffer", hasOutputBuffer);
+    output.Set("stream", hasOutputBuffer);
+    // Other attributes
+    Napi::Object container = Napi::Object::New(env);
+    container.Set("id", f);
+    container.Set("input", input);
+    container.Set("output", output);
+    // Add to set of formats
+    format.Set(f, container);
+  }
+
+  // Raw, uncompressed data
+  Napi::Boolean supported = Napi::Boolean::New(env, true);
+  Napi::Boolean unsupported = Napi::Boolean::New(env, false);
+  Napi::Object rawInput = Napi::Object::New(env);
+  rawInput.Set("file", unsupported);
+  rawInput.Set("buffer", supported);
+  rawInput.Set("stream", supported);
+  Napi::Object rawOutput = Napi::Object::New(env);
+  rawOutput.Set("file", unsupported);
+  rawOutput.Set("buffer", supported);
+  rawOutput.Set("stream", supported);
+  Napi::Object raw = Napi::Object::New(env);
+  raw.Set("id", "raw");
+  raw.Set("input", rawInput);
+  raw.Set("output", rawOutput);
+  format.Set("raw", raw);
+
+  return format;
+}
+
+/*
+  Synchronous, internal-only method used by some of the functional tests.
+  Calculates the maximum colour distance using the DE2000 algorithm
+  between two images of the same dimensions and number of channels.
+*/
+Napi::Value _maxColourDistance(const Napi::CallbackInfo& info) {
+  Napi::Env env = info.Env();
+
+  // Open input files
+  VImage image1;
+  sharp::ImageType imageType1 = sharp::DetermineImageType(info[0].As<Napi::String>().Utf8Value().data());
+  if (imageType1 != sharp::ImageType::UNKNOWN) {
+    try {
+      image1 = VImage::new_from_file(info[0].As<Napi::String>().Utf8Value().c_str());
+    } catch (...) {
+      throw Napi::Error::New(env, "Input file 1 has corrupt header");
+    }
+  } else {
+    throw Napi::Error::New(env, "Input file 1 is of an unsupported image format");
+  }
+  VImage image2;
+  sharp::ImageType imageType2 = sharp::DetermineImageType(info[1].As<Napi::String>().Utf8Value().data());
+  if (imageType2 != sharp::ImageType::UNKNOWN) {
+    try {
+      image2 = VImage::new_from_file(info[1].As<Napi::String>().Utf8Value().c_str());
+    } catch (...) {
+      throw Napi::Error::New(env, "Input file 2 has corrupt header");
+    }
+  } else {
+    throw Napi::Error::New(env, "Input file 2 is of an unsupported image format");
+  }
+  // Ensure same number of channels
+  if (image1.bands() != image2.bands()) {
+    throw Napi::Error::New(env, "mismatchedBands");
+  }
+  // Ensure same dimensions
+  if (image1.width() != image2.width() || image1.height() != image2.height()) {
+    throw Napi::Error::New(env, "mismatchedDimensions");
+  }
+
+  double maxColourDistance;
+  try {
+    // Premultiply and remove alpha
+    if (sharp::HasAlpha(image1)) {
+      image1 = image1.premultiply().extract_band(1, VImage::option()->set("n", image1.bands() - 1));
+    }
+    if (sharp::HasAlpha(image2)) {
+      image2 = image2.premultiply().extract_band(1, VImage::option()->set("n", image2.bands() - 1));
+    }
+    // Calculate colour distance
+    maxColourDistance = image1.dE00(image2).max();
+  } catch (vips::VError const &err) {
+    throw Napi::Error::New(env, err.what());
+  }
+
+  // Clean up libvips' per-request data and threads
+  vips_error_clear();
+  vips_thread_shutdown();
+
+  return Napi::Number::New(env, maxColourDistance);
+}
+
+#if defined(__GNUC__)
+// mallctl will be resolved by the runtime linker when jemalloc is being used
+extern "C" {
+  int mallctl(const char *name, void *oldp, size_t *oldlenp, void *newp, size_t newlen) __attribute__((weak));
+}
+Napi::Value _isUsingJemalloc(const Napi::CallbackInfo& info) {
+  Napi::Env env = info.Env();
+  return Napi::Boolean::New(env, mallctl != nullptr);
+}
+#else
+Napi::Value _isUsingJemalloc(const Napi::CallbackInfo& info) {
+  Napi::Env env = info.Env();
+  return Napi::Boolean::New(env, false);
+}
+#endif

src/utilities.h

@@ -0,0 +1,29 @@
+// Copyright 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Lovell Fuller and contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef SRC_UTILITIES_H_
+#define SRC_UTILITIES_H_
+
+#include <napi.h>
+
+Napi::Value cache(const Napi::CallbackInfo& info);
+Napi::Value concurrency(const Napi::CallbackInfo& info);
+Napi::Value counters(const Napi::CallbackInfo& info);
+Napi::Value simd(const Napi::CallbackInfo& info);
+Napi::Value libvipsVersion(const Napi::CallbackInfo& info);
+Napi::Value format(const Napi::CallbackInfo& info);
+Napi::Value _maxColourDistance(const Napi::CallbackInfo& info);
+Napi::Value _isUsingJemalloc(const Napi::CallbackInfo& info);
+
+#endif  // SRC_UTILITIES_H_

test/bench/package.json

@@ -0,0 +1,23 @@
+{
+  "name": "sharp-benchmark",
+  "version": "0.0.1",
+  "private": true,
+  "author": "Lovell Fuller <npm@lovell.info>",
+  "description": "Benchmark and performance tests for sharp",
+  "scripts": {
+    "test": "node perf && node random && node parallel"
+  },
+  "devDependencies": {
+    "async": "3.2.0",
+    "benchmark": "2.1.4",
+    "gm": "1.23.1",
+    "imagemagick": "0.1.3",
+    "jimp": "0.16.1",
+    "mapnik": "4.5.6",
+    "semver": "7.3.4"
+  },
+  "license": "Apache-2.0",
+  "engines": {
+    "node": "14"
+  }
+}

test/bench/parallel.js

@@ -0,0 +1,45 @@
+'use strict';
+
+process.env.UV_THREADPOOL_SIZE = 64;
+
+const assert = require('assert');
+const async = require('async');
+
+const sharp = require('../../');
+const fixtures = require('../fixtures');
+
+const width = 720;
+const height = 480;
+
+sharp.concurrency(1);
+sharp.simd(true);
+
+const timer = setInterval(function () {
+  console.dir(sharp.counters());
+}, 100);
+
+async.mapSeries([1, 1, 2, 4, 8, 16, 32, 64], function (parallelism, next) {
+  const start = new Date().getTime();
+  async.times(parallelism,
+    function (id, callback) {
+      /* jslint unused: false */
+      sharp(fixtures.inputJpg).resize(width, height).toBuffer(function (err, buffer) {
+        buffer = null;
+        callback(err, new Date().getTime() - start);
+      });
+    },
+    function (err, ids) {
+      assert(!err);
+      assert(ids.length === parallelism);
+      ids.sort();
+      const mean = ids.reduce(function (a, b) {
+        return a + b;
+      }) / ids.length;
+      console.log(parallelism + ' parallel calls: fastest=' + ids[0] + 'ms slowest=' + ids[ids.length - 1] + 'ms mean=' + mean + 'ms');
+      next();
+    }
+  );
+}, function () {
+  clearInterval(timer);
+  console.dir(sharp.counters());
+});

test/bench/perf.js

@@ -0,0 +1,915 @@
+'use strict';
+
+const os = require('os');
+const fs = require('fs');
+
+const async = require('async');
+const assert = require('assert');
+const Benchmark = require('benchmark');
+
+// Contenders
+const sharp = require('../../');
+const gm = require('gm');
+const imagemagick = require('imagemagick');
+const mapnik = require('mapnik');
+const jimp = require('jimp');
+
+const fixtures = require('../fixtures');
+
+const outputJpg = fixtures.path('output.jpg');
+const outputPng = fixtures.path('output.png');
+const outputWebP = fixtures.path('output.webp');
+
+const width = 720;
+const height = 588;
+
+// Disable libvips cache to ensure tests are as fair as they can be
+sharp.cache(false);
+
+// Spawn one thread per CPU
+sharp.concurrency(os.cpus().length);
+
+async.series({
+  jpeg: function (callback) {
+    const inputJpgBuffer = fs.readFileSync(fixtures.inputJpg);
+    const jpegSuite = new Benchmark.Suite('jpeg');
+    // jimp
+    jpegSuite.add('jimp-buffer-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        jimp.read(inputJpgBuffer, function (err, image) {
+          if (err) {
+            throw err;
+          } else {
+            image
+              .resize(width, height, jimp.RESIZE_BICUBIC)
+              .quality(80)
+              .getBuffer(jimp.MIME_JPEG, function (err) {
+                if (err) {
+                  throw err;
+                } else {
+                  deferred.resolve();
+                }
+              });
+          }
+        });
+      }
+    }).add('jimp-file-file', {
+      defer: true,
+      fn: function (deferred) {
+        jimp.read(fixtures.inputJpg, function (err, image) {
+          if (err) {
+            throw err;
+          } else {
+            image
+              .resize(width, height, jimp.RESIZE_BICUBIC)
+              .quality(80)
+              .write(outputJpg, function (err) {
+                if (err) {
+                  throw err;
+                } else {
+                  deferred.resolve();
+                }
+              });
+          }
+        });
+      }
+    });
+    // mapnik
+    jpegSuite.add('mapnik-file-file', {
+      defer: true,
+      fn: function (deferred) {
+        mapnik.Image.open(fixtures.inputJpg, function (err, img) {
+          if (err) throw err;
+          img
+            .resize(width, height, {
+              scaling_method: mapnik.imageScaling.lanczos
+            })
+            .save(outputJpg, 'jpeg:quality=80', function (err) {
+              if (err) throw err;
+              deferred.resolve();
+            });
+        });
+      }
+    }).add('mapnik-buffer-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        mapnik.Image.fromBytes(inputJpgBuffer, { max_size: 3000 }, function (err, img) {
+          if (err) throw err;
+          img
+            .resize(width, height, {
+              scaling_method: mapnik.imageScaling.lanczos
+            })
+            .encode('jpeg:quality=80', function (err) {
+              if (err) throw err;
+              deferred.resolve();
+            });
+        });
+      }
+    });
+    // imagemagick
+    jpegSuite.add('imagemagick-file-file', {
+      defer: true,
+      fn: function (deferred) {
+        imagemagick.resize({
+          srcPath: fixtures.inputJpg,
+          dstPath: outputJpg,
+          quality: 0.8,
+          width: width,
+          height: height,
+          format: 'jpg',
+          filter: 'Lanczos'
+        }, function (err) {
+          if (err) {
+            throw err;
+          } else {
+            deferred.resolve();
+          }
+        });
+      }
+    });
+    // gm
+    jpegSuite.add('gm-buffer-file', {
+      defer: true,
+      fn: function (deferred) {
+        gm(inputJpgBuffer)
+          .filter('Lanczos')
+          .resize(width, height)
+          .quality(80)
+          .write(outputJpg, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('gm-buffer-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        gm(inputJpgBuffer)
+          .filter('Lanczos')
+          .resize(width, height)
+          .quality(80)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('gm-file-file', {
+      defer: true,
+      fn: function (deferred) {
+        gm(fixtures.inputJpg)
+          .filter('Lanczos')
+          .resize(width, height)
+          .quality(80)
+          .write(outputJpg, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('gm-file-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        gm(fixtures.inputJpg)
+          .filter('Lanczos')
+          .resize(width, height)
+          .quality(80)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    });
+    // sharp
+    jpegSuite.add('sharp-buffer-file', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .toFile(outputJpg, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-buffer-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-file-file', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(fixtures.inputJpg)
+          .resize(width, height)
+          .toFile(outputJpg, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-stream-stream', {
+      defer: true,
+      fn: function (deferred) {
+        const readable = fs.createReadStream(fixtures.inputJpg);
+        const writable = fs.createWriteStream(outputJpg);
+        writable.on('finish', function () {
+          deferred.resolve();
+        });
+        const pipeline = sharp()
+          .resize(width, height);
+        readable.pipe(pipeline).pipe(writable);
+      }
+    }).add('sharp-file-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(fixtures.inputJpg)
+          .resize(width, height)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-promise', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .toBuffer()
+          .then(function (buffer) {
+            assert.notStrictEqual(null, buffer);
+            deferred.resolve();
+          })
+          .catch(function (err) {
+            throw err;
+          });
+      }
+    }).on('cycle', function (event) {
+      console.log('jpeg ' + String(event.target));
+    }).on('complete', function () {
+      callback(null, this.filter('fastest').map('name'));
+    }).run();
+  },
+  // Effect of applying operations
+  operations: function (callback) {
+    const inputJpgBuffer = fs.readFileSync(fixtures.inputJpg);
+    const operationsSuite = new Benchmark.Suite('operations');
+    operationsSuite.add('sharp-sharpen-mild', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .sharpen()
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-sharpen-radius', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .sharpen(3, 1, 3)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-blur-mild', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .blur()
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-blur-radius', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .blur(3)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-gamma', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .gamma()
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-normalise', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .normalise()
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-greyscale', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .greyscale()
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-greyscale-gamma', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .gamma()
+          .greyscale()
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-progressive', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .jpeg({ progressive: true })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-without-chroma-subsampling', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .jpeg({ chromaSubsampling: '4:4:4' })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-rotate', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .rotate(90)
+          .resize(width, height)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-without-simd', {
+      defer: true,
+      fn: function (deferred) {
+        sharp.simd(false);
+        sharp(inputJpgBuffer)
+          .resize(width, height)
+          .toBuffer(function (err, buffer) {
+            sharp.simd(true);
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-sequentialRead', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer, { sequentialRead: true })
+          .resize(width, height)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-crop-entropy', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height, {
+            fit: 'cover',
+            position: sharp.strategy.entropy
+          })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-crop-attention', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height, {
+            fit: 'cover',
+            position: sharp.strategy.attention
+          })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).on('cycle', function (event) {
+      console.log('operations ' + String(event.target));
+    }).on('complete', function () {
+      callback(null, this.filter('fastest').map('name'));
+    }).run();
+  },
+  // Comparative speed of kernels
+  kernels: function (callback) {
+    const inputJpgBuffer = fs.readFileSync(fixtures.inputJpg);
+    (new Benchmark.Suite('kernels')).add('sharp-cubic', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height, { kernel: 'cubic' })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-lanczos2', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height, { kernel: 'lanczos2' })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-lanczos3', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputJpgBuffer)
+          .resize(width, height, { kernel: 'lanczos3' })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).on('cycle', function (event) {
+      console.log('kernels ' + String(event.target));
+    }).on('complete', function () {
+      callback(null, this.filter('fastest').map('name'));
+    }).run();
+  },
+  // PNG
+  png: function (callback) {
+    const inputPngBuffer = fs.readFileSync(fixtures.inputPngAlphaPremultiplicationLarge);
+    const pngSuite = new Benchmark.Suite('png');
+    const minSamples = 64;
+    // jimp
+    pngSuite.add('jimp-buffer-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        jimp.read(inputPngBuffer, function (err, image) {
+          if (err) {
+            throw err;
+          } else {
+            image
+              .resize(width, height)
+              .deflateLevel(6)
+              .filterType(0)
+              .getBuffer(jimp.MIME_PNG, function (err) {
+                if (err) {
+                  throw err;
+                } else {
+                  deferred.resolve();
+                }
+              });
+          }
+        });
+      }
+    }).add('jimp-file-file', {
+      defer: true,
+      fn: function (deferred) {
+        jimp.read(fixtures.inputPngAlphaPremultiplicationLarge, function (err, image) {
+          if (err) {
+            throw err;
+          } else {
+            image
+              .resize(width, height)
+              .deflateLevel(6)
+              .filterType(0)
+              .write(outputPng, function (err) {
+                if (err) {
+                  throw err;
+                } else {
+                  deferred.resolve();
+                }
+              });
+          }
+        });
+      }
+    });
+    // mapnik
+    pngSuite.add('mapnik-file-file', {
+      defer: true,
+      fn: function (deferred) {
+        mapnik.Image.open(fixtures.inputPngAlphaPremultiplicationLarge, function (err, img) {
+          if (err) throw err;
+          img.premultiply(function (err, img) {
+            if (err) throw err;
+            img.resize(width, height, {
+              scaling_method: mapnik.imageScaling.lanczos
+            }, function (err, img) {
+              if (err) throw err;
+              img.demultiply(function (err, img) {
+                if (err) throw err;
+                img.save(outputPng, 'png', function (err) {
+                  if (err) throw err;
+                  deferred.resolve();
+                });
+              });
+            });
+          });
+        });
+      }
+    }).add('mapnik-buffer-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        mapnik.Image.fromBytes(inputPngBuffer, { max_size: 3000 }, function (err, img) {
+          if (err) throw err;
+          img.premultiply(function (err, img) {
+            if (err) throw err;
+            img.resize(width, height, {
+              scaling_method: mapnik.imageScaling.lanczos
+            }, function (err, img) {
+              if (err) throw err;
+              img.demultiply(function (err, img) {
+                if (err) throw err;
+                img.encode('png', function (err) {
+                  if (err) throw err;
+                  deferred.resolve();
+                });
+              });
+            });
+          });
+        });
+      }
+    });
+    // imagemagick
+    pngSuite.add('imagemagick-file-file', {
+      defer: true,
+      fn: function (deferred) {
+        imagemagick.resize({
+          srcPath: fixtures.inputPngAlphaPremultiplicationLarge,
+          dstPath: outputPng,
+          width: width,
+          height: height,
+          filter: 'Lanczos',
+          customArgs: [
+            '-define', 'PNG:compression-level=6',
+            '-define', 'PNG:compression-filter=0'
+          ]
+        }, function (err) {
+          if (err) {
+            throw err;
+          } else {
+            deferred.resolve();
+          }
+        });
+      }
+    });
+    // gm
+    pngSuite.add('gm-file-file', {
+      defer: true,
+      fn: function (deferred) {
+        gm(fixtures.inputPngAlphaPremultiplicationLarge)
+          .filter('Lanczos')
+          .resize(width, height)
+          .define('PNG:compression-level=6')
+          .define('PNG:compression-filter=0')
+          .write(outputPng, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('gm-file-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        gm(fixtures.inputPngAlphaPremultiplicationLarge)
+          .filter('Lanczos')
+          .resize(width, height)
+          .define('PNG:compression-level=6')
+          .define('PNG:compression-filter=0')
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    });
+    // sharp
+    pngSuite.add('sharp-buffer-file', {
+      defer: true,
+      minSamples,
+      fn: function (deferred) {
+        sharp(inputPngBuffer)
+          .resize(width, height)
+          .png({ compressionLevel: 6 })
+          .toFile(outputPng, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-buffer-buffer', {
+      defer: true,
+      minSamples,
+      fn: function (deferred) {
+        sharp(inputPngBuffer)
+          .resize(width, height)
+          .png({ compressionLevel: 6 })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-file-file', {
+      defer: true,
+      minSamples,
+      fn: function (deferred) {
+        sharp(fixtures.inputPngAlphaPremultiplicationLarge)
+          .resize(width, height)
+          .png({ compressionLevel: 6 })
+          .toFile(outputPng, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-file-buffer', {
+      defer: true,
+      minSamples,
+      fn: function (deferred) {
+        sharp(fixtures.inputPngAlphaPremultiplicationLarge)
+          .resize(width, height)
+          .png({ compressionLevel: 6 })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-progressive', {
+      defer: true,
+      minSamples,
+      fn: function (deferred) {
+        sharp(inputPngBuffer)
+          .resize(width, height)
+          .png({ compressionLevel: 6, progressive: true })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-adaptiveFiltering', {
+      defer: true,
+      minSamples,
+      fn: function (deferred) {
+        sharp(inputPngBuffer)
+          .resize(width, height)
+          .png({ adaptiveFiltering: true, compressionLevel: 6 })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-compressionLevel=9', {
+      defer: true,
+      minSamples,
+      fn: function (deferred) {
+        sharp(inputPngBuffer)
+          .resize(width, height)
+          .png({ compressionLevel: 9 })
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    });
+    pngSuite.on('cycle', function (event) {
+      console.log(' png ' + String(event.target));
+    }).on('complete', function () {
+      callback(null, this.filter('fastest').map('name'));
+    }).run();
+  },
+  // WebP
+  webp: function (callback) {
+    const inputWebPBuffer = fs.readFileSync(fixtures.inputWebP);
+    (new Benchmark.Suite('webp')).add('sharp-buffer-file', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputWebPBuffer)
+          .resize(width, height)
+          .toFile(outputWebP, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-buffer-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(inputWebPBuffer)
+          .resize(width, height)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-file-file', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(fixtures.inputWebP)
+          .resize(width, height)
+          .toFile(outputWebP, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('sharp-file-buffer', {
+      defer: true,
+      fn: function (deferred) {
+        sharp(fixtures.inputWebP)
+          .resize(width, height)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    }).on('cycle', function (event) {
+      console.log('webp ' + String(event.target));
+    }).on('complete', function () {
+      callback(null, this.filter('fastest').map('name'));
+    }).run();
+  }
+}, function (err, results) {
+  assert(!err, err);
+  Object.keys(results).forEach(function (format) {
+    if (results[format].toString().substr(0, 5) !== 'sharp') {
+      console.log('sharp was slower than ' + results[format] + ' for ' + format);
+    }
+  });
+  console.dir(sharp.cache());
+});

test/bench/random.js

@@ -0,0 +1,75 @@
+'use strict';
+
+const imagemagick = require('imagemagick');
+const gm = require('gm');
+const assert = require('assert');
+const Benchmark = require('benchmark');
+
+const sharp = require('../../');
+const fixtures = require('../fixtures');
+
+sharp.cache(false);
+sharp.simd(true);
+
+const min = 320;
+const max = 960;
+
+const randomDimension = function () {
+  return Math.ceil((Math.random() * (max - min)) + min);
+};
+
+new Benchmark.Suite('random').add('imagemagick', {
+  defer: true,
+  fn: function (deferred) {
+    imagemagick.resize({
+      srcPath: fixtures.inputJpg,
+      dstPath: fixtures.path('output.jpg'),
+      quality: 0.8,
+      width: randomDimension(),
+      height: randomDimension(),
+      format: 'jpg',
+      filter: 'Lanczos'
+    }, function (err) {
+      if (err) {
+        throw err;
+      } else {
+        deferred.resolve();
+      }
+    });
+  }
+}).add('gm', {
+  defer: true,
+  fn: function (deferred) {
+    gm(fixtures.inputJpg)
+      .resize(randomDimension(), randomDimension())
+      .filter('Lanczos')
+      .quality(80)
+      .toBuffer(function (err, buffer) {
+        if (err) {
+          throw err;
+        } else {
+          assert.notStrictEqual(null, buffer);
+          deferred.resolve();
+        }
+      });
+  }
+}).add('sharp', {
+  defer: true,
+  fn: function (deferred) {
+    sharp(fixtures.inputJpg)
+      .resize(randomDimension(), randomDimension())
+      .toBuffer(function (err, buffer) {
+        if (err) {
+          throw err;
+        } else {
+          assert.notStrictEqual(null, buffer);
+          deferred.resolve();
+        }
+      });
+  }
+}).on('cycle', function (event) {
+  console.log(String(event.target));
+}).on('complete', function () {
+  const winner = this.filter('fastest').map('name');
+  assert.strictEqual('sharp', String(winner), 'sharp was slower than ' + winner);
+}).run();

test/coverage/report.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+CPPFLAGS="--coverage" LDFLAGS="--coverage" npm rebuild
+npm test
+geninfo --no-external --base-directory src --output-file coverage/sharp.info build/Release/obj.target/sharp/src
+genhtml --title sharp --demangle-cpp --output-directory coverage/sharp coverage/*.info