Upgrade nan to fix clang linking problem #259

See #189 and jcupitt/libvips@fbe321e

.gitignore

@@ -1,18 +1,9 @@
-lib-cov
-*.seed
-*.log
-*.csv
-*.dat
-*.out
-*.pid
-*.gz
-
-pids
-logs
-results
 build
 node_modules
-tests/output.jpg
-tests/output.png
+coverage
+test/bench/node_modules
+test/fixtures/output*
+test/leak/libvips.supp
 
-npm-debug.log
+# Mac OS X
+.DS_Store

.jshintignore

@@ -0,0 +1,3 @@
+node_modules
+test/bench/node_modules
+coverage

.jshintrc

@@ -0,0 +1,11 @@
+{
+  "strict": true,
+  "node": true,
+  "maxparams": 4,
+  "maxcomplexity": 13,
+  "globals": {
+    "before": true,
+    "describe": true,
+    "it": true
+  }
+}

.npmignore

@@ -0,0 +1,10 @@
+build
+node_modules
+coverage
+.jshintignore
+.jshintrc
+.gitignore
+test
+.travis.yml
+appveyor.yml
+mkdocs.yml

.travis.yml

@@ -0,0 +1,17 @@
+language: node_js
+node_js:
+  - "0.10"
+  - "0.12"
+  - "iojs-v2"
+  - "iojs-v3"
+addons:
+  apt:
+    sources:
+    - ubuntu-toolchain-r-test
+    packages:
+    - g++-4.8
+before_install:
+  - sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.8 90
+  - curl -s https://raw.githubusercontent.com/lovell/sharp/master/preinstall.sh | sudo bash -
+after_success:
+  - cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js

CONTRIBUTING.md

@@ -0,0 +1,90 @@
+# 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.
+
+New bugs are assigned a `triage` label whilst under investigation.
+
+If you're having problems with `npm install sharp`, please include the output of the following commands, perhaps as a [gist](https://gist.github.com/):
+
+```sh
+vips -v
+pkg-config --print-provides vips
+npm install --verbose sharp
+```
+
+## 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](http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/ch03.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` 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.
+
+| Release | WIP branch |
+| ------: | :--------- |
+| v0.11.0 | knife      |
+| v0.12.0 | look       |
+| v0.13.0 | mind       |
+
+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. Methods with mandatory parameters often have names like `doSomethingWith(X)`.
+
+Please ensure backwards compatibility where possible. Methods to modify previously default behaviour often have names like `withoutOptionY()` or `withExtraZ()`.
+
+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 [bilinearInterpolation method](https://github.com/lovell/sharp/blob/v0.6.0/index.js#L155) present in v0.5.0 was deprecated in v0.6.0 and removed in v0.7.0.
+
+## 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) or contact me by [e-mail](https://github.com/lovell/sharp/blob/master/package.json#L4).

README.md

@@ -1,156 +1,30 @@
-# sharp
+# sharp
 
-_adj_
+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.
 
-1. clearly defined; distinct: a sharp photographic image. 
-2. quick, brisk, or spirited. 
-3. shrewd or astute: a sharp bargainer. 
-4. (Informal.) very stylish: a sharp dresser; a sharp jacket. 
+[![Test Coverage](https://coveralls.io/repos/lovell/sharp/badge.png?branch=master)](https://coveralls.io/r/lovell/sharp?branch=master)
 
-The typical use case for this high speed Node.js module is to convert large JPEG and PNG images to smaller JPEG and PNG images of varying dimensions.
+### Documentation
 
-It is somewhat opinionated in that it only deals with JPEG and PNG images, always obeys the requested dimensions by either cropping or embedding and insists on a mild sharpen of the resulting image.
+Visit [sharp.dimens.io](http://sharp.dimens.io/) for
+complete installation instructions, API documentation,
+benchmark tests and a changelog.
 
-Under the hood you'll find the blazingly fast [libvips](https://github.com/jcupitt/libvips) image processing library, originally created in 1989 at Birkbeck College and currently maintained by the University of Southampton.
+### Contributing
 
-Performance is 4x-8x faster than ImageMagick and 2x-4x faster than GraphicsMagick, based mainly on the number of CPU cores available.
+A [guide for contributors](https://github.com/lovell/sharp/blob/master/CONTRIBUTING.md)
+covers reporting bugs, requesting features and submitting code changes.
 
-## Prerequisites
+### Licence
 
-* Node.js v0.8+
-* node-gyp
-* [libvips](https://github.com/jcupitt/libvips) v7.37+
-
-For the sharpest results, please compile libvips from source.
-
-If you prefer to run a stable, package-managed environment such as Ubuntu 12.04 LTS, [v0.0.3](https://github.com/lovell/sharp/tree/v0.0.3) will work with the libvips-dev package.
-
-## Install
-
-	npm install sharp
-
-## Usage
-
-	var sharp = require("sharp");
-
-### crop(input, output, width, height, callback)
-
-Scale and crop to `width` x `height` calling `callback` when complete.
-
-```javascript
-sharp.crop("input.jpg", "output.jpg", 300, 200, function(err) {
-  if (err) {
-    throw err;
-  }
-  // output.jpg is a 300 pixels wide and 200 pixels high image
-  // containing a scaled and cropped version of input.jpg
-});
-```
-
-```javascript
-sharp.crop("input.jpg", sharp.buffer.jpeg, 300, 200, function(err, buffer) {
-  if (err) {
-    throw err;
-  }
-  // buffer contains JPEG image data
-});
-```
-
-```javascript
-sharp.crop("input.jpg", sharp.buffer.png, 300, 200, function(err, buffer) {
-  if (err) {
-    throw err;
-  }
-  // buffer contains PNG image data (converted from JPEG)
-});
-```
-
-### embedWhite(input, output, width, height, callback)
-
-Scale and embed to `width` x `height` using a white canvas calling `callback` when complete.
-
-```javascript
-sharp.embedWhite("input.jpg", "output.jpg", 200, 300, function(err) {
-  if (err) {
-    throw err;
-  }
-  // output.jpg is a 200 pixels wide and 300 pixels high image
-  // containing a scaled version of input.png embedded on a white canvas
-});
-```
-
-```javascript
-sharp.embedWhite("input.jpg", sharp.buffer.jpeg, 200, 300, function(err, buffer) {
-  if (err) {
-    throw err;
-  }
-  // buffer contains JPEG image data
-});
-```
-
-### embedBlack(input, output, width, height, callback)
-
-Scale and embed to `width` x `height` using a black canvas calling `callback` when complete.
-
-```javascript
-sharp.embedBlack("input.png", "output.png", 200, 300, function(err) {
-  if (err) {
-    throw err;
-  }
-  // output.png is a 200 pixels wide and 300 pixels high image
-  // containing a scaled version of input.png embedded on a black canvas
-});
-```
-
-### Parameters common to all methods
-
-#### input
-
-String containing the filename to read from.
-
-#### output
-
-One of:
-* String containing the filename to write to.
-* `sharp.buffer.jpeg` to pass a Buffer containing JPEG image data to `callback`.
-* `sharp.buffer.png` to pass a Buffer containing PNG image data to `callback`.
-
-## Testing
-
-	npm test
-
-## Performance
-
-Test environment:
-
-* AMD Athlon 4 core 3.3GHz 512KB L2 CPU 1333 DDR3
-* libvips 7.37
-* libjpeg-turbo8 1.3.0
-* libpng 1.6.6
-* zlib1g 1.2.7
-
-#### JPEG
-
-* imagemagick x 5.53 ops/sec ±0.55% (31 runs sampled)
-* gm x 10.86 ops/sec ±0.43% (56 runs sampled)
-* epeg x 28.07 ops/sec ±0.07% (70 runs sampled)
-* sharp-file x 31.60 ops/sec ±8.80% (80 runs sampled)
-* sharp-buffer x 34.04 ops/sec ±0.36% (82 runs sampled)
-
-#### PNG
-
-* imagemagick x 4.65 ops/sec ±0.37% (27 runs sampled)
-* gm x 21.65 ops/sec ±0.18% (56 runs sampled)
-* sharp-file x 39.47 ops/sec ±6.78% (68 runs sampled)
-* sharp-buffer x 42.87 ops/sec ±0.19% (71 runs sampled)
-
-## Licence
-
-Copyright 2013, 2014 Lovell Fuller
+Copyright 2013, 2014, 2015 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
+[http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0.html)
 
 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 +1,28 @@
+os: Visual Studio 2015
+version: "{build}"
+build: off
+platform: x64
+environment:
+  VIPS_VERSION_MAJOR_MINOR: 8.0
+  VIPS_VERSION_PATCH: 2
+  VIPS_WARNING: 0
+  matrix:
+  - nodejs_version: "0.10"
+    nodejs_exec: "node"
+  - nodejs_version: "0.12"
+    nodejs_exec: "node"
+  - nodejs_version: "2"
+    nodejs_exec: "iojs"
+  - nodejs_version: "3"
+    nodejs_exec: "iojs"
+install:
+  - ps: $env:VIPS_VERSION = "$env:VIPS_VERSION_MAJOR_MINOR.$env:VIPS_VERSION_PATCH"
+  - ps: Write-Output "Fetching http://www.vips.ecs.soton.ac.uk/supported/$env:VIPS_VERSION_MAJOR_MINOR/win32/vips-dev-$env:VIPS_VERSION.zip"
+  - ps: Start-FileDownload http://www.vips.ecs.soton.ac.uk/supported/$env:VIPS_VERSION_MAJOR_MINOR/win32/vips-dev-$env:VIPS_VERSION.zip -FileName c:\vips-dev-$env:VIPS_VERSION.zip
+  - ps: Invoke-Expression "& 7z -y x c:\vips-dev-$env:VIPS_VERSION.zip -oc:\ | FIND /V `"ing  `""
+  - ps: $env:VIPS_HOME = "c:\vips-dev-$env:VIPS_VERSION"
+  - ps: $env:PATH = "$env:VIPS_HOME\bin;$env:PATH"
+  - ps: Install-Product node $env:nodejs_version x86
+  - npm install --arch=ia32 --msvs_version=2013
+test_script:
+  - npm run-script test-win32-%nodejs_exec%

binding.gyp

@@ -1,17 +1,88 @@
 {
   'targets': [{
     'target_name': 'sharp',
-    'sources': ['src/sharp.cc'],
-    'libraries': [
-      '<!@(PKG_CONFIG_PATH="/usr/local/lib/pkgconfig" pkg-config --libs vips)',
-      '<!@(PKG_CONFIG_PATH="/usr/lib/pkgconfig" pkg-config --libs vips)'
+    'sources': [
+      'src/common.cc',
+      'src/metadata.cc',
+      'src/operations.cc',
+      'src/pipeline.cc',
+      'src/sharp.cc',
+      'src/utilities.cc'
     ],
-    'include_dirs': [
-      '/usr/include/glib-2.0',
-      '/usr/lib/glib-2.0/include',
-      '/usr/lib/x86_64-linux-gnu/glib-2.0/include'
+    'conditions': [
+        ['OS=="win"', {
+            'library_dirs': [
+                '$(VIPS_HOME)/lib'
+            ],
+            'libraries': [
+                'libvips.dll.a',
+                'glib-2.0.lib',
+                'gobject-2.0.lib',
+                'gthread-2.0.lib',
+                'gmodule-2.0.lib',
+                'liblcms2.dll.a',
+                'libxml2.lib',
+                'intl.lib',
+                'libjpeg.dll.a',
+                'libexif.dll.a',
+                'libpng.lib',
+                'libtiff.dll.a',
+                'libMagickWand-6.Q16.dll.a',
+                'libMagickCore-6.Q16.dll.a',
+                'pango-1.0.lib',
+                'pangoft2-1.0.lib',
+                'libgsf-1.dll.a',
+                'libopenslide.dll.a',
+                'libfftw3.dll.a'
+            ],
+            'include_dirs': [
+                '$(VIPS_HOME)/include',
+                '$(VIPS_HOME)/include/glib-2.0',
+                '$(VIPS_HOME)/lib/glib-2.0/include',
+                '<!(node -e "require(\'nan\')")'
+            ]
+        }, {
+            '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'
+            },
+            'libraries': [
+                '<!(PKG_CONFIG_PATH="<(PKG_CONFIG_PATH)" pkg-config --libs vips)'
+            ],
+            'include_dirs': [
+                '<!(PKG_CONFIG_PATH="<(PKG_CONFIG_PATH)" pkg-config --cflags vips glib-2.0)',
+                '<!(node -e "require(\'nan\')")'
+            ]
+        }]
     ],
-    'cflags': ['-fexceptions'],
-    'cflags_cc': ['-fexceptions']
+    'cflags_cc': [
+      '-std=c++0x',
+      '-fexceptions',
+      '-Wall',
+      '-O3'
+    ],
+    'xcode_settings': {
+      'OTHER_CPLUSPLUSFLAGS': [
+        '-std=c++11',
+        '-stdlib=libc++',
+        '-fexceptions',
+        '-Wall',
+        '-O3'
+      ],
+      'MACOSX_DEPLOYMENT_TARGET': '10.7'
+    },
+    'msvs_settings': {
+      'VCCLCompilerTool': {
+        'ExceptionHandling': 1 # /EHsc
+      }
+    },
+    'configurations': {
+      'Release': {
+        'msvs_settings': {
+          'VCCLCompilerTool': {
+            'ExceptionHandling': 1,
+          }
+        }
+      }
+    },
   }]
 }

docs/api.md

@@ -0,0 +1,597 @@
+# API
+
+```javascript
+var sharp = require('sharp');
+```
+
+### Input
+
+#### sharp([input])
+
+Constructor to which further methods are chained. `input`, if present, can be one of:
+
+* Buffer containing JPEG, PNG, WebP, GIF* or TIFF image data, or
+* String containing the filename of an image, with most major formats supported.
+
+The object returned implements the
+[stream.Duplex](http://nodejs.org/api/stream.html#stream_class_stream_duplex) class.
+
+JPEG, PNG, WebP, GIF* or TIFF format image data
+can be streamed into the object when `input` is not provided.
+
+JPEG, PNG or WebP format image data can be streamed out from this object.
+
+\* libvips 8.0.0+ is required for Buffer/Stream input of GIF and other `magick` formats.
+
+```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
+  });
+```
+
+#### metadata([callback])
+
+Fast access to image metadata without decoding any compressed image data.
+
+`callback`, if present, gets the arguments `(err, metadata)` where `metadata` has the attributes:
+
+* `format`: Name of decoder to be used to decompress image data e.g. `jpeg`, `png`, `webp` (for file-based input additionally `tiff`, `magick` and `openslide`)
+* `width`: Number of pixels wide
+* `height`: Number of pixels high
+* `space`: Name of colour space interpretation e.g. `srgb`, `rgb`, `scrgb`, `cmyk`, `lab`, `xyz`, `b-w` [...](https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L522)
+* `channels`: Number of bands e.g. `3` for sRGB, `4` for CMYK
+* `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
+
+A Promises/A+ promise is returned when `callback` is not provided.
+
+```javascript
+var 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
+  });
+```
+
+#### clone()
+
+Takes a "snapshot" of the 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.
+
+```javascript
+var pipeline = sharp().rotate();
+pipeline.clone().resize(800, 600).pipe(firstWritableStream);
+pipeline.clone().extract(20, 20, 100, 100).pipe(secondWritableStream);
+readableStream.pipe(pipeline);
+// firstWritableStream receives auto-rotated, resized readableStream
+// secondWritableStream receives auto-rotated, extracted region of readableStream
+```
+
+#### 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.
+
+#### limitInputPixels(pixels)
+
+Do not process input images where the number of pixels (width * height) exceeds this limit.
+
+`pixels` is the integral Number of pixels, with a value between 1 and the default 268402689 (0x3FFF * 0x3FFF).
+
+### Resizing
+
+#### resize([width], [height])
+
+Scale output to `width` x `height`. By default, the resized image is cropped to the exact size specified.
+
+`width` is the integral Number of pixels wide the resultant image should be, between 1 and 16383 (0x3FFF). Use `null` or `undefined` to auto-scale the width to match the height.
+
+`height` is the integral Number of pixels high the resultant image should be, between 1 and 16383. Use `null` or `undefined` to auto-scale the height to match the width.
+
+#### crop([gravity])
+
+Crop the resized image to the exact size specified, the default behaviour.
+
+`gravity`, if present, is a String or an attribute of the `sharp.gravity` Object e.g. `sharp.gravity.north`.
+
+Possible values are `north`, `east`, `south`, `west`, `center` and `centre`. The default gravity is `center`/`centre`.
+
+```javascript
+var transformer = sharp()
+  .resize(300, 200)
+  .crop(sharp.gravity.north)
+  .on('error', function(err) {
+    console.log(err);
+  });
+// Read image data from readableStream, resize and write image data to writableStream
+readableStream.pipe(transformer).pipe(writableStream);
+```
+
+#### embed()
+
+Preserving aspect ratio, resize the image to the
+maximum `width` or `height` specified
+then embed on a background of the exact
+`width` and `height` specified.
+
+If the background contains an alpha value
+then WebP and PNG format output images will
+contain an alpha channel,
+even when the input image does not.
+
+```javascript
+sharp('input.gif')
+  .resize(200, 300)
+  .background({r: 0, g: 0, b: 0, a: 0})
+  .embed()
+  .toFormat(sharp.format.webp)
+  .toBuffer(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 transparent canvas, of input.gif
+  });
+```
+
+#### max()
+
+Preserving aspect ratio,
+resize the image to be as large as possible
+while ensuring its dimensions are less than or equal to
+the `width` and `height` specified.
+
+Both `width` and `height` must be provided via
+`resize` otherwise the behaviour will default to `crop`.
+
+```javascript
+sharp(inputBuffer)
+  .resize(200, 200)
+  .max()
+  .toFormat('jpeg')
+  .toBuffer()
+  .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
+  });
+```
+
+#### min()
+
+Preserving aspect ratio,
+resize the image to be as small as possible
+while ensuring its dimensions are greater than or equal to
+the `width` and `height` specified.
+
+Both `width` and `height` must be provided via `resize` otherwise the behaviour will default to `crop`.
+
+#### 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*".
+
+#### ignoreAspectRatio()
+
+Ignoring the aspect ratio of the input, stretch the image to the exact `width` and/or `height` provided via `resize`.
+
+#### interpolateWith(interpolator)
+
+Use the given interpolator for image resizing, where `interpolator` is an attribute of the `sharp.interpolator` Object e.g. `sharp.interpolator.bicubic`.
+
+Possible interpolators, in order of performance, are:
+
+* `nearest`: Use [nearest neighbour interpolation](http://en.wikipedia.org/wiki/Nearest-neighbor_interpolation), suitable for image enlargement only.
+* `bilinear`: Use [bilinear interpolation](http://en.wikipedia.org/wiki/Bilinear_interpolation), the default and fastest image reduction interpolation.
+* `bicubic`: Use [bicubic interpolation](http://en.wikipedia.org/wiki/Bicubic_interpolation), which typically reduces performance by 5%.
+* `vertexSplitQuadraticBasisSpline`: Use [VSQBS interpolation](https://github.com/jcupitt/libvips/blob/master/libvips/resample/vsqbs.cpp#L48), which prevents "staircasing" and typically reduces performance by 5%.
+* `locallyBoundedBicubic`: Use [LBB interpolation](https://github.com/jcupitt/libvips/blob/master/libvips/resample/lbb.cpp#L100), which prevents some "[acutance](http://en.wikipedia.org/wiki/Acutance)" and typically reduces performance by a factor of 2.
+* `nohalo`: Use [Nohalo interpolation](http://eprints.soton.ac.uk/268086/), which prevents acutance and typically reduces performance by a factor of 3.
+
+```javascript
+sharp(inputBuffer)
+  .resize(200, 300)
+  .interpolateWith(sharp.interpolator.nohalo)
+  .background('white')
+  .embed()
+  .toFile('output.tiff')
+  .then(function() {
+    // output.tiff is a 200 pixels wide and 300 pixels high image
+    // containing a nohalo scaled version, embedded on a white canvas,
+    // of the image data in inputBuffer
+  });
+```
+
+### Operations
+
+#### extract(top, left, width, height)
+
+Extract a region of the image. Can be used with or without a `resize` operation.
+
+`top` and `left` are the offset, in pixels, from the top-left corner.
+
+`width` and `height` are the dimensions of the extracted image.
+
+Use `extract` before `resize` for pre-resize extraction. Use `extract` after `resize` for post-resize extraction. Use `extract` before and after for both.
+
+```javascript
+sharp(input)
+  .extract(top, left, width, height)
+  .toFile(output, function(err) {
+    // Extract a region of the input image, saving in the same format.
+  });
+```
+
+```javascript
+sharp(input)
+  .extract(topOffsetPre, leftOffsetPre, widthPre, heightPre)
+  .resize(width, height)
+  .extract(topOffsetPost, leftOffsetPost, widthPost, heightPost)
+  .toFile(output, function(err) {
+    // Extract a region, resize, then extract from the resized image
+  });
+```
+
+#### background(rgba)
+
+Set the background for the `embed` and `flatten` operations.
+
+`rgba` is parsed by the [color](https://www.npmjs.org/package/color) module to extract values for red, green, blue and alpha.
+
+The alpha value is a float between `0` (transparent) and `1` (opaque).
+
+The default background is `{r: 0, g: 0, b: 0, a: 1}`, black without transparency.
+
+#### flatten()
+
+Merge alpha transparency channel, if any, with `background`.
+
+#### rotate([angle])
+
+Rotate the output image by either an explicit angle or auto-orient based on the EXIF `Orientation` tag.
+
+`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. Mirroring is supported and may infer the use of a `flip` operation.
+
+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)`.
+
+The use of `rotate` implies the removal of the EXIF `Orientation` tag, if any.
+
+```javascript
+var pipeline = sharp()
+  .rotate()
+  .resize(null, 200)
+  .progressive()
+  .toBuffer(function(err, outputBuffer, info) {
+    if (err) {
+      throw err;
+    }
+    // outputBuffer contains 200px high progressive JPEG image data,
+    // auto-rotated using EXIF Orientation tag
+    // info.width and info.height contain the dimensions of the resized image
+  });
+readableStream.pipe(pipeline);
+```
+
+#### 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.
+
+#### 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.
+
+#### blur([sigma])
+
+When used without parameters, performs a fast, mild blur of the output image. This typically reduces performance by 10%.
+
+When a `sigma` is provided, performs a slower, more accurate Gaussian blur. This typically reduces performance by 25%.
+
+* `sigma`, if present, is a Number between 0.3 and 1000 representing the approximate blur radius in pixels.
+
+#### sharpen([radius], [flat], [jagged])
+
+When used without parameters, performs a fast, mild sharpen of the output image. This typically reduces performance by 10%.
+
+When a `radius` 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. This typically reduces performance by 50%.
+
+* `radius`, if present, is an integral Number representing the sharpen mask radius in pixels.
+* `flat`, if present, is a Number representing the level of sharpening to apply to "flat" areas, defaulting to a value of 1.0.
+* `jagged`, if present, is a Number representing the level of sharpening to apply to "jagged" areas, defaulting to a value of 2.0.
+
+#### gamma([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`.
+
+`gamma`, if present, is a Number betweem 1 and 3. The default value is `2.2`, a suitable approximation for sRGB images.
+
+This can improve the perceived brightness of a resized image in non-linear colour spaces.
+
+JPEG input images will not take advantage of the shrink-on-load performance optimisation when applying a gamma correction.
+
+#### grayscale() / 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.
+
+The output image will still be web-friendly sRGB and contain three (identical) channels.
+
+#### normalize() / normalise()
+
+Enhance output image contrast by stretching its luminance to cover the full dynamic range. This typically reduces performance by 30%.
+
+#### overlayWith(filename)
+
+_Experimental_
+
+Alpha composite `filename` over the processed (resized, extracted) image. The dimensions of the two images must match.
+
+* `filename` is a String containing the filename of an image with an alpha channel.
+
+```javascript
+sharp('input.png')
+  .rotate(180)
+  .resize(300)
+  .flatten()
+  .background('#ff6600')
+  .overlayWith('overlay.png')
+  .sharpen()
+  .withMetadata()
+  .quality(90)
+  .webp()
+  .toBuffer()
+  .then(function(outputBuffer) {
+    // outputBuffer contains upside down, 300px wide, alpha channel flattened
+    // onto orange background, composited with overlay.png, sharpened,
+    // with metadata, 90% quality WebP image data. Phew!
+  });
+```
+
+### Output
+
+#### 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, TIFF and DZI supported.
+
+`callback`, if present, is called with two arguments `(err, info)` where:
+
+* `err` contains an error message, if any.
+* `info` contains the output image `format`, `size` (bytes), `width` and `height`.
+
+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 by default. JPEG, PNG and WebP are supported.
+
+`callback`, if present, gets three arguments `(err, buffer, info)` where:
+
+* `err` is an error message, if any.
+* `buffer` is the output image data.
+* `info` contains the output image `format`, `size` (bytes), `width` and `height`.
+
+A Promises/A+ promise is returned when `callback` is not provided.
+
+#### jpeg()
+
+Use JPEG format for the output image.
+
+#### png()
+
+Use PNG format for the output image.
+
+#### webp()
+
+Use WebP format for the output image.
+
+#### raw()
+
+_Requires libvips 7.42.0+_
+
+Provide raw, uncompressed uint8 (unsigned char) image data for Buffer and Stream based output.
+
+The number of channels depends on the input image and selected options.
+
+* 1 channel for images converted to `greyscale()`, with each byte representing one pixel.
+* 3 channels for colour images without alpha transparency, with bytes ordered \[red, green, blue, red, green, blue, etc.\]).
+* 4 channels for colour images with alpha transparency, with bytes ordered \[red, green, blue, alpha, red, green, blue, alpha, etc.\].
+
+#### toFormat(format)
+
+Convenience method for the above output format methods, where `format` is either:
+
+* an attribute of the `sharp.format` Object e.g. `sharp.format.jpeg`, or
+* a String containing `jpeg`, `png`, `webp` or `raw`.
+
+#### 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.
+
+#### 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.
+
+#### withMetadata([metadata])
+
+Include all metadata (EXIF, XMP, IPTC) from the input image in the output image.
+This will also convert to and add the latest web-friendly v2 sRGB ICC profile.
+
+The optional `metadata` parameter, if present, is an Object with the attributes to update.
+New attributes cannot be inserted, only existing attributes updated.
+
+* `orientation` is an integral Number between 0 and 7, used to update the value of the EXIF `Orientation` tag.
+This has no effect if the input image does not have an EXIF `Orientation` tag.
+
+The default behaviour, when `withMetadata` is not used, is to strip all metadata and convert to the device-independent sRGB colour space.
+
+#### tile([size], [overlap])
+
+The size and overlap, in pixels, of square Deep Zoom image pyramid tiles.
+
+* `size` is an integral Number between 1 and 8192. The default value is 256 pixels.
+* `overlap` is an integral Number between 0 and 8192. The default value is 0 pixels.
+
+```javascript
+sharp('input.tiff').tile(256).toFile('output.dzi', function(err, info) {
+  // The output.dzi file is the XML format Deep Zoom definition
+  // The output_files directory contains 256x256 pixel tiles grouped by zoom level
+});
+```
+
+#### withoutChromaSubsampling()
+
+Disable the use of [chroma subsampling](http://en.wikipedia.org/wiki/Chroma_subsampling) with JPEG output (4:4:4).
+
+This can improve colour representation at higher quality settings (90+),
+but usually increases output file size and typically reduces performance by 25%.
+
+The default behaviour is to use chroma subsampling (4:2:0).
+
+#### 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 0 and 9.
+
+#### withoutAdaptiveFiltering()
+
+_Requires libvips 7.42.0+_
+
+An advanced setting to disable adaptive row filtering for the lossless PNG output format.
+
+#### trellisQuantisation() / trellisQuantization()
+
+_Requires libvips 8.0.0+ compiled against mozjpeg 3.0+_
+
+An advanced setting to apply the use of
+[trellis quantisation](http://en.wikipedia.org/wiki/Trellis_quantization) with JPEG output.
+Reduces file size and slightly increases relative quality at the cost of increased compression time.
+
+#### overshootDeringing()
+
+_Requires libvips 8.0.0+ compiled against mozjpeg 3.0+_
+
+An advanced setting to reduce the effects of
+[ringing](http://en.wikipedia.org/wiki/Ringing_%28signal%29) in JPEG output,
+in particular where black text appears on a white background (or vice versa).
+
+#### optimiseScans() / optimizeScans()
+
+_Requires libvips 8.0.0+ compiled against mozjpeg 3.0+_
+
+An advanced setting for progressive (interlace) JPEG output.
+Calculates which spectrum of DCT coefficients uses the fewest bits.
+Usually reduces file size at the cost of increased compression time.
+
+### Attributes
+
+#### format
+
+An Object containing nested boolean values
+representing the available input and output formats/methods,
+for example:
+
+```javascript
+> console.dir(sharp.format);
+
+{ jpeg: { id: 'jpeg',
+    input: { file: true, buffer: true, stream: true },
+    output: { file: true, buffer: true, stream: true } },
+  png: { id: 'png',
+    input: { file: true, buffer: true, stream: true },
+    output: { file: true, buffer: true, stream: true } },
+  webp: { id: 'webp',
+    input: { file: true, buffer: true, stream: true },
+    output: { file: true, buffer: true, stream: true } },
+  tiff: { id: 'tiff',
+    input: { file: true, buffer: true, stream: true },
+    output: { file: true, buffer: false, stream: false } },
+  magick: { id: 'magick',
+    input: { file: true, buffer: true, stream: true },
+    output: { file: false, buffer: false, stream: false } },
+  raw: { id: 'raw',
+    input: { file: false, buffer: false, stream: false },
+    output: { file: false, buffer: true, stream: true } } }
+```
+
+#### queue
+
+An EventEmitter that emits a `change` event when a task is either:
+
+* queued, waiting for _libuv_ to provide a worker thread
+* complete
+
+```javascript
+sharp.queue.on('change', function(queueLength) {
+  console.log('Queue contains ' + queueLength + ' task(s)');
+});
+```
+
+### Utilities
+
+#### sharp.cache([memory], [items])
+
+If `memory` or `items` are provided, set the limits of _libvips'_ operation cache.
+
+* `memory` is the maximum memory in MB to use for this cache, with a default value of 100
+* `items` is the maximum number of operations to cache, with a default value of 500
+
+This method always returns cache statistics, useful for determining how much working memory is required for a particular task.
+
+```javascript
+var stats = sharp.cache(); // { current: 75, high: 99, memory: 100, items: 500 }
+sharp.cache(200); // { current: 75, high: 99, memory: 200, items: 500 }
+sharp.cache(50, 200); // { current: 49, high: 99, memory: 50, items: 200}
+```
+
+#### sharp.concurrency([threads])
+
+`threads`, if provided, is the Number of threads _libvips'_ should create for processing each image. The default value is the number of CPU cores. A value of `0` will reset to this default.
+
+This method always returns the current concurrency.
+
+```javascript
+var threads = sharp.concurrency(); // 4
+sharp.concurrency(2); // 2
+sharp.concurrency(0); // 4
+```
+
+The maximum number of images that can be processed in parallel is limited by libuv's `UV_THREADPOOL_SIZE` environment variable.
+
+#### sharp.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.
+
+```javascript
+var counters = sharp.counters(); // { queue: 2, process: 4 }
+```

docs/changelog.md

@@ -0,0 +1,81 @@
+# Changelog
+
+### v0.11 - "*knife*"
+
+#### v0.11.2 - 28<sup>th</sup> August 2015
+
+* Allow crop gravity to be provided as a String.
+  [#255](https://github.com/lovell/sharp/pull/255)
+  [@papandreou](https://github.com/papandreou)
+* Add support for io.js v3 and Node v4.
+  [#246](https://github.com/lovell/sharp/issues/246)
+
+#### v0.11.1 - 12<sup>th</sup> August 2015
+
+* Silence MSVC warning: "C4530: C++ exception handler used, but unwind semantics are not enabled".
+  [#244](https://github.com/lovell/sharp/pull/244)
+  [@TheThing](https://github.com/TheThing)
+
+* Suppress gamma correction for input image with alpha transparency.
+  [#249](https://github.com/lovell/sharp/issues/249)
+  [@compeak](https://github.com/compeak)
+
+#### v0.11.0 - 15<sup>th</sup> July 2015
+
+* Allow alpha transparency compositing via new `overlayWith` method.
+  [#97](https://github.com/lovell/sharp/issues/97)
+  [@gasi](https://github.com/gasi)
+
+* Expose raw ICC profile data as a Buffer when using `metadata`.
+  [#129](https://github.com/lovell/sharp/issues/129)
+  [@homerjam](https://github.com/homerjam)
+
+* Allow image header updates via a parameter passed to existing `withMetadata` method.
+  Provide initial support for EXIF `Orientation` tag,
+  which if present is now removed when using `rotate`, `flip` or `flop`.
+  [#189](https://github.com/lovell/sharp/issues/189)
+  [@h2non](https://github.com/h2non)
+
+* Tighten constructor parameter checks.
+  [#221](https://github.com/lovell/sharp/issues/221)
+  [@mikemorris](https://github.com/mikemorris)
+
+* Allow one input Stream to be shared with two or more output Streams via new `clone` method.
+  [#235](https://github.com/lovell/sharp/issues/235)
+  [@jaubourg](https://github.com/jaubourg)
+
+* Use `round` instead of `floor` when auto-scaling dimensions to avoid floating-point rounding errors.
+  [#238](https://github.com/lovell/sharp/issues/238)
+  [@richardadjogah](https://github.com/richardadjogah)
+
+### v0.10 - "*judgment*"
+
+#### v0.10.1 - 1<sup>st</sup> June 2015
+
+* Allow embed of image with alpha transparency onto non-transparent background.
+  [#204](https://github.com/lovell/sharp/issues/204)
+  [@mikemliu](https://github.com/mikemliu)
+
+* Include C standard library for `atoi` as Xcode 6.3 appears to no longer do this.
+  [#228](https://github.com/lovell/sharp/issues/228)
+  [@doggan](https://github.com/doggan)
+
+#### v0.10.0 - 23<sup>rd</sup> April 2015
+
+* Add support for Windows (x86).
+  [#19](https://github.com/lovell/sharp/issues/19)
+  [@DullReferenceException](https://github.com/DullReferenceException)
+  [@itsananderson](https://github.com/itsananderson)
+
+* Add support for Openslide input and DeepZoom output.
+  [#146](https://github.com/lovell/sharp/issues/146)
+  [@mvictoras](https://github.com/mvictoras)
+
+* Allow arbitrary aspect ratios when resizing images via new `ignoreAspectRatio` method.
+  [#192](https://github.com/lovell/sharp/issues/192)
+  [@skedastik](https://github.com/skedastik)
+
+* Enhance output image contrast by stretching its luminance to cover the full dynamic range via new `normalize` method.
+  [#194](https://github.com/lovell/sharp/issues/194)
+  [@bkw](https://github.com/bkw)
+  [@codingforce](https://github.com/codingforce)

docs/index.md

@@ -0,0 +1,103 @@
+# sharp
+
+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.
+
+Resizing an image is typically 4x faster than using
+the quickest ImageMagick and GraphicsMagick settings.
+
+[![Test Coverage](https://coveralls.io/repos/lovell/sharp/badge.png?branch=master)](https://coveralls.io/r/lovell/sharp?branch=master)
+
+### Formats
+
+This module supports reading JPEG, PNG, WebP, TIFF, OpenSlide,
+GIF and other libmagick-supported formats.
+
+Output images can be in JPEG, PNG and WebP 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)
+and [Leaflet](https://github.com/turban/Leaflet.Zoomify).
+
+### Features
+
+As well as image resizing, operations such as
+rotation, extraction, compositing and gamma correction are available.
+
+Colour spaces, embedded ICC profiles and alpha transparency channels
+are all handled correctly.
+
+### Fast
+
+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](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/A+ are supported.
+
+### Optimal
+
+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 can be disabled,
+which for diagrams and line art often produces the same result
+as [pngcrush](http://pmt.sourceforge.net/pngcrush/).
+
+### Contributing
+
+A [guide for contributors](https://github.com/lovell/sharp/blob/master/CONTRIBUTING.md)
+covers reporting bugs, requesting features and submitting code changes.
+
+### Credits
+
+This module would never have been possible without
+the help and code contributions of the following people:
+
+* [John Cupitt](https://github.com/jcupitt)
+* [Pierre Inglebert](https://github.com/pierreinglebert)
+* [Jonathan Ong](https://github.com/jonathanong)
+* [Chanon Sajjamanochai](https://github.com/chanon)
+* [Juliano Julio](https://github.com/julianojulio)
+* [Daniel Gasienica](https://github.com/gasi)
+* [Julian Walker](https://github.com/julianwa)
+* [Amit Pitaru](https://github.com/apitaru)
+* [Brandon Aaron](https://github.com/brandonaaron)
+* [Andreas Lind](https://github.com/papandreou)
+* [Maurus Cuelenaere](https://github.com/mcuelenaere)
+* [Linus Unnebäck](https://github.com/LinusU)
+* [Victor Mateevitsi](https://github.com/mvictoras)
+* [Alaric Holloway](https://github.com/skedastik)
+* [Bernhard K. Weisshuhn](https://github.com/bkw)
+
+Thank you!
+
+### Licence
+
+Copyright 2013, 2014, 2015 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)
+
+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/install.md

@@ -0,0 +1,123 @@
+# Installation
+
+```sh
+npm install sharp
+```
+
+### Prerequisites
+
+* Node.js v0.10+ or io.js
+* [libvips](https://github.com/jcupitt/libvips) v7.40.0+ (7.42.0+ recommended)
+* C++11 compatible compiler such as gcc 4.6+, clang 3.0+ or MSVC 2013 (io.js v3+ requires gcc 4.8+)
+
+### Linux
+
+[![Ubuntu 12.04 Build Status](https://travis-ci.org/lovell/sharp.png?branch=master)](https://travis-ci.org/lovell/sharp)
+[![Centos 6.5 Build Status](https://snap-ci.com/lovell/sharp/branch/master/build_image)](https://snap-ci.com/lovell/sharp/branch/master)
+
+For a system-wide installation of the most suitable version of
+libvips and its dependencies on the following Operating Systems:
+
+* Debian 7, 8
+* Ubuntu 12.04, 14.04, 14.10, 15.04
+* Mint 13, 17
+* RHEL/Centos/Scientific 6, 7
+* Fedora 21, 22
+* Amazon Linux 2014.09, 2015.03
+* OpenSuse 13
+
+run the following as a user with `sudo` access:
+
+```sh
+curl -s https://raw.githubusercontent.com/lovell/sharp/master/preinstall.sh | sudo bash -
+```
+
+or run the following as `root`:
+
+```sh
+curl -s https://raw.githubusercontent.com/lovell/sharp/master/preinstall.sh | bash -
+```
+
+The [preinstall.sh](https://github.com/lovell/sharp/blob/master/preinstall.sh) script requires `curl` and `pkg-config`.
+
+Add `--with-openslide` to enable OpenSlide support:
+
+```sh
+curl -s https://raw.githubusercontent.com/lovell/sharp/master/preinstall.sh | sudo bash -s -- --with-openslide
+```
+
+#### Ubuntu LTS
+
+libvips v7.40.6 is available via a PPA.
+
+##### 12.04
+
+```sh
+sudo add-apt-repository -y ppa:lovell/precise-backport-vips
+sudo apt-get update
+sudo apt-get install -y libvips-dev libgsf-1-dev
+```
+
+##### 14.04
+
+```sh
+sudo add-apt-repository -y ppa:lovell/trusty-backport-vips
+sudo apt-get update
+sudo apt-get install -y libvips-dev libgsf-1-dev
+```
+
+### Mac OS
+
+[![OS X 10.9.5 Build Status](https://travis-ci.org/lovell/sharp-osx-ci.png?branch=master)](https://travis-ci.org/lovell/sharp-osx-ci)
+
+Install libvips via homebrew:
+
+```sh
+brew install homebrew/science/vips --with-webp --with-graphicsmagick
+```
+
+A missing or incorrectly configured _Xcode Command Line Tools_ installation
+[can lead](https://github.com/lovell/sharp/issues/80) to a
+`library not found for -ljpeg` error.
+If so, please try: `xcode-select --install`.
+
+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`.
+
+### Windows
+
+[![Windows Server 2012 Build Status](https://ci.appveyor.com/api/projects/status/pgtul704nkhhg6sg)](https://ci.appveyor.com/project/lovell/sharp)
+
+Requires x86 32-bit Node.js or io.js (use `iojs.exe` rather than `node.exe`).
+
+The WebP format is currently unsupported.
+
+1. Ensure the [node-gyp prerequisites](https://github.com/TooTallNate/node-gyp#installation) are met.
+2. [Download](http://www.vips.ecs.soton.ac.uk/supported/current/win32/) and unzip `vips-dev.x.y.z.zip`.
+3. Set the `VIPS_HOME` environment variable to the full path of the `vips-dev-x.y.z` directory.
+4. Add `vips-dev-x.y.z\bin` to `PATH`.
+
+Versions of MSVC more recent than 2013 may require the use of `npm install --arch=ia32 --msvs_version=2013`.
+
+### Heroku
+
+[Alessandro Tagliapietra](https://github.com/alex88) maintains an
+[Heroku buildpack for libvips](https://github.com/alex88/heroku-buildpack-vips)
+and its dependencies.
+
+### Docker
+
+[Marc Bachmann](https://github.com/marcbachmann) maintains a
+[Dockerfile for libvips](https://github.com/marcbachmann/dockerfile-libvips).
+
+```sh
+docker pull marcbachmann/libvips
+```
+
+### Build tools
+
+* [gulp-responsive](https://www.npmjs.com/package/gulp-responsive)
+* [gulp-sharp](https://www.npmjs.com/package/gulp-sharp)
+* [grunt-sharp](https://www.npmjs.com/package/grunt-sharp)

docs/performance.md

@@ -0,0 +1,63 @@
+# Performance
+
+### Test environment
+
+* AWS EC2 [c4.xlarge](http://aws.amazon.com/ec2/instance-types/#c4)
+* Ubuntu 15.04
+* Node.js 0.12.7
+* libvips 8.0.2
+* liborc 0.4.22
+
+### The contenders
+
+* [lwip](https://www.npmjs.com/package/lwip) 0.0.7 - Wrapper around CImg, compiles dependencies from source
+* [imagemagick-native](https://www.npmjs.com/package/imagemagick-native) git@45d4e2e - Wrapper around libmagick++, supports Buffers only.
+* [imagemagick](https://www.npmjs.com/package/imagemagick) 0.1.3 - Supports filesystem only and "*has been unmaintained for a long time*".
+* [gm](https://www.npmjs.com/package/gm) 1.18.1 - Fully featured wrapper around GraphicsMagick's `convert` command line utility.
+* sharp 0.11.0 - Caching within libvips disabled to ensure a fair comparison.
+
+### The task
+
+Decompress a 2725x2225 JPEG image, resize to 720x480 using bilinear interpolation, then compress to JPEG.
+
+### Results
+
+| Module             | Input  | Output | Ops/sec | Speed-up |
+| :----------------- | :----- | :----- | ------: | -------: |
+| lwip               | file   | file   |    1.75 |        1 |
+| lwip               | buffer | buffer |    2.21 |      1.3 |
+| imagemagick-native | buffer | buffer |    7.13 |      4.1 |
+| gm                 | buffer | buffer |    7.27 |      4.2 |
+| gm                 | file   | file   |    7.33 |      4.2 |
+| imagemagick        | file   | file   |   10.04 |      5.7 |
+| sharp              | stream | stream |   23.12 |     13.2 |
+| sharp              | file   | file   |   24.43 |     14.0 |
+| sharp              | file   | buffer |   24.55 |     14.0 |
+| sharp              | buffer | file   |   24.86 |     14.2 |
+| sharp              | buffer | buffer |   24.92 |     14.2 |
+
+Greater performance can be expected with caching enabled (default) and using 8+ core machines.
+
+The I/O limits of the relevant (de)compression library will generally determine maximum throughput.
+
+### Benchmark test prerequisites
+
+Requires both _ImageMagick_ and _GraphicsMagick_:
+
+```sh
+brew install imagemagick
+brew install graphicsmagick
+```
+
+```sh
+sudo apt-get install imagemagick graphicsmagick libmagick++-dev
+```
+
+### Running the benchmark test
+
+```sh
+git clone https://github.com/lovell/sharp.git
+cd sharp/test/bench
+npm install
+npm test
+```

index.js

@@ -1,18 +1,836 @@
-var sharp = require("./build/Release/sharp");
-
-module.exports.buffer = {
-  jpeg: "__jpeg",
-  png: "__png"
-};
-
-module.exports.crop = function(input, output, width, height, callback) {
-  sharp.resize(input, output, width, height, "c", callback);
-};
-
-module.exports.embedWhite = function(input, output, width, height, callback) {
-  sharp.resize(input, output, width, height, "w", callback);
-};
-
-module.exports.embedBlack = function(input, output, width, height, callback) {
-  sharp.resize(input, output, width, height, "b", callback);
-};
+'use strict';
+
+var path = require('path');
+var util = require('util');
+var stream = require('stream');
+var events = require('events');
+
+var semver = require('semver');
+var color = require('color');
+var BluebirdPromise = require('bluebird');
+
+var sharp = require('./build/Release/sharp');
+var libvipsVersion = sharp.libvipsVersion();
+
+var maximum = {
+  width: 0x3FFF,
+  height: 0x3FFF,
+  pixels: Math.pow(0x3FFF, 2)
+};
+
+var Sharp = function(input) {
+  if (!(this instanceof Sharp)) {
+    return new Sharp(input);
+  }
+  stream.Duplex.call(this);
+  this.options = {
+    // input options
+    bufferIn: null,
+    streamIn: false,
+    sequentialRead: false,
+    limitInputPixels: maximum.pixels,
+    // ICC profiles
+    iccProfilePath: path.join(__dirname, 'icc') + path.sep,
+    // resize options
+    topOffsetPre: -1,
+    leftOffsetPre: -1,
+    widthPre: -1,
+    heightPre: -1,
+    topOffsetPost: -1,
+    leftOffsetPost: -1,
+    widthPost: -1,
+    heightPost: -1,
+    width: -1,
+    height: -1,
+    canvas: 'crop',
+    gravity: 0,
+    angle: 0,
+    rotateBeforePreExtract: false,
+    flip: false,
+    flop: false,
+    withoutEnlargement: false,
+    interpolator: 'bilinear',
+    // operations
+    background: [0, 0, 0, 255],
+    flatten: false,
+    blurSigma: 0,
+    sharpenRadius: 0,
+    sharpenFlat: 1,
+    sharpenJagged: 2,
+    gamma: 0,
+    greyscale: false,
+    normalize: 0,
+    // overlay
+    overlayPath: '',
+    // output options
+    output: '__input',
+    progressive: false,
+    quality: 80,
+    compressionLevel: 6,
+    withoutAdaptiveFiltering: false,
+    withoutChromaSubsampling: false,
+    trellisQuantisation: false,
+    overshootDeringing: false,
+    optimiseScans: false,
+    streamOut: false,
+    withMetadata: false,
+    withMetadataOrientation: -1,
+    tileSize: 256,
+    tileOverlap: 0,
+    // Function to notify of queue length changes
+    queueListener: function(queueLength) {
+      module.exports.queue.emit('change', queueLength);
+    }
+  };
+  if (typeof input === 'string') {
+    // input=file
+    this.options.fileIn = input;
+  } else if (typeof input === 'object' && input instanceof Buffer) {
+    // input=buffer
+    this.options.bufferIn = input;
+  } else if (typeof input === 'undefined') {
+    // input=stream
+    this.options.streamIn = true;
+  } else {
+    throw new Error('Unsupported input ' + typeof input);
+  }
+  return this;
+};
+module.exports = Sharp;
+util.inherits(Sharp, stream.Duplex);
+
+/*
+  EventEmitter singleton emits queue length 'change' events
+*/
+module.exports.queue = new events.EventEmitter();
+
+/*
+  Supported image formats
+*/
+module.exports.format = sharp.format();
+
+/*
+  Handle incoming chunk on Writable Stream
+*/
+Sharp.prototype._write = function(chunk, encoding, callback) {
+  /*jslint unused: false */
+  if (this.options.streamIn) {
+    if (typeof chunk === 'object' && chunk instanceof Buffer) {
+      if (this.options.bufferIn instanceof Buffer) {
+        // Append to existing Buffer
+        this.options.bufferIn = Buffer.concat(
+          [this.options.bufferIn, chunk],
+          this.options.bufferIn.length + chunk.length
+        );
+      } else {
+        // Create new Buffer
+        this.options.bufferIn = new Buffer(chunk.length);
+        chunk.copy(this.options.bufferIn);
+      }
+      callback();
+    } else {
+      callback(new Error('Non-Buffer data on Writable Stream'));
+    }
+  } else {
+    callback(new Error('Unexpected data on Writable Stream'));
+  }
+};
+
+// Crop this part of the resized image (Center/Centre, North, East, South, West)
+module.exports.gravity = {'center': 0, 'centre': 0, 'north': 1, 'east': 2, 'south': 3, 'west': 4};
+
+Sharp.prototype.crop = function(gravity) {
+  this.options.canvas = 'crop';
+  if (typeof gravity === 'number' && !Number.isNaN(gravity) && gravity >= 0 && gravity <= 4) {
+    this.options.gravity = gravity;
+  } else if (typeof gravity === 'string' && typeof module.exports.gravity[gravity] === 'number') {
+    this.options.gravity = module.exports.gravity[gravity];
+  } else {
+    throw new Error('Unsupported crop gravity ' + gravity);
+  }
+  return this;
+};
+
+Sharp.prototype.extract = function(topOffset, leftOffset, width, height) {
+  /*jslint unused: false */
+  var suffix = this.options.width === -1 && this.options.height === -1 ? 'Pre' : 'Post';
+  var values = arguments;
+  ['topOffset', 'leftOffset', 'width', 'height'].forEach(function(name, index) {
+    if (typeof values[index] === 'number' && !Number.isNaN(values[index]) && (values[index] % 1 === 0) && values[index] >= 0) {
+      this.options[name + suffix] = values[index];
+    } else {
+      throw new Error('Non-integer value for ' + name + ' of ' + values[index]);
+    }
+  }.bind(this));
+  // Ensure existing rotation occurs before pre-resize extraction
+  if (suffix === 'Pre' && this.options.angle !== 0) {
+    this.options.rotateBeforePreExtract = true;
+  }
+  return this;
+};
+
+/*
+  Set the background colour for embed and flatten operations.
+  Delegates to the 'Color' module, which can throw an Error
+  but is liberal in what it accepts, clamping values to sensible min/max.
+*/
+Sharp.prototype.background = function(rgba) {
+  var colour = color(rgba);
+  this.options.background = colour.rgbArray();
+  this.options.background.push(colour.alpha() * 255);
+  return this;
+};
+
+Sharp.prototype.embed = function() {
+  this.options.canvas = 'embed';
+  return this;
+};
+
+Sharp.prototype.max = function() {
+  this.options.canvas = 'max';
+  return this;
+};
+
+Sharp.prototype.min = function() {
+  this.options.canvas = 'min';
+  return this;
+};
+
+/*
+  Ignoring the aspect ratio of the input, stretch the image to
+  the exact width and/or height provided via the resize method.
+*/
+Sharp.prototype.ignoreAspectRatio = function() {
+  this.options.canvas = 'ignore_aspect';
+  return this;
+};
+
+Sharp.prototype.flatten = function(flatten) {
+  this.options.flatten = (typeof flatten === 'boolean') ? flatten : true;
+  return this;
+};
+
+Sharp.prototype.overlayWith = function(overlayPath) {
+  if (typeof overlayPath !== 'string') {
+    throw new Error('The overlay path must be a string');
+  }
+  if (overlayPath === '') {
+    throw new Error('The overlay path cannot be empty');
+  }
+  this.options.overlayPath = overlayPath;
+  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;
+};
+
+/*
+  Flip the image vertically, about the Y axis
+*/
+Sharp.prototype.flip = function(flip) {
+  this.options.flip = (typeof flip === 'boolean') ? flip : true;
+  return this;
+};
+
+/*
+  Flop the image horizontally, about the X axis
+*/
+Sharp.prototype.flop = function(flop) {
+  this.options.flop = (typeof flop === 'boolean') ? flop : true;
+  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;
+};
+
+/*
+  Blur the output image.
+  Call without a sigma to use a fast, mild blur.
+  Call with a sigma to use a slower, more accurate Gaussian blur.
+*/
+Sharp.prototype.blur = function(sigma) {
+  if (typeof sigma === 'undefined') {
+    // No arguments: default to mild blur
+    this.options.blurSigma = -1;
+  } else if (typeof sigma === 'boolean') {
+    // Boolean argument: apply mild blur?
+    this.options.blurSigma = sigma ? -1 : 0;
+  } else if (typeof sigma === 'number' && !Number.isNaN(sigma) && sigma >= 0.3 && sigma <= 1000) {
+    // Numeric argument: specific sigma
+    this.options.blurSigma = sigma;
+  } else {
+    throw new Error('Invalid blur sigma (0.3 to 1000.0) ' + sigma);
+  }
+  return this;
+};
+
+/*
+  Sharpen the output image.
+  Call without a radius to use a fast, mild sharpen.
+  Call with a radius to use a slow, accurate sharpen using the L of LAB colour space.
+    radius - size of mask in pixels, must be integer
+    flat - level of "flat" area sharpen, default 1
+    jagged - level of "jagged" area sharpen, default 2
+*/
+Sharp.prototype.sharpen = function(radius, flat, jagged) {
+  if (typeof radius === 'undefined') {
+    // No arguments: default to mild sharpen
+    this.options.sharpenRadius = -1;
+  } else if (typeof radius === 'boolean') {
+    // Boolean argument: apply mild sharpen?
+    this.options.sharpenRadius = radius ? -1 : 0;
+  } else if (typeof radius === 'number' && !Number.isNaN(radius) && (radius % 1 === 0) && radius >= 1) {
+    // Numeric argument: specific radius
+    this.options.sharpenRadius = radius;
+    // Control over flat areas
+    if (typeof flat !== 'undefined' && flat !== null) {
+      if (typeof flat === 'number' && !Number.isNaN(flat) && flat >= 0) {
+        this.options.sharpenFlat = flat;
+      } else {
+        throw new Error('Invalid sharpen level for flat areas ' + flat + ' (expected >= 0)');
+      }
+    }
+    // Control over jagged areas
+    if (typeof jagged !== 'undefined' && jagged !== null) {
+      if (typeof jagged === 'number' && !Number.isNaN(jagged) && jagged >= 0) {
+        this.options.sharpenJagged = jagged;
+      } else {
+        throw new Error('Invalid sharpen level for jagged areas ' + jagged + ' (expected >= 0)');
+      }
+    }
+  } else {
+    throw new Error('Invalid sharpen radius ' + radius + ' (expected integer >= 1)');
+  }
+  return this;
+};
+
+/*
+  Set the interpolator to use for the affine transformation
+*/
+module.exports.interpolator = {
+  nearest: 'nearest',
+  bilinear: 'bilinear',
+  bicubic: 'bicubic',
+  nohalo: 'nohalo',
+  locallyBoundedBicubic: 'lbb',
+  vertexSplitQuadraticBasisSpline: 'vsqbs'
+};
+Sharp.prototype.interpolateWith = function(interpolator) {
+  var isValid = false;
+  for (var key in module.exports.interpolator) {
+    if (module.exports.interpolator[key] === interpolator) {
+      isValid = true;
+      break;
+    }
+  }
+  if (isValid) {
+    this.options.interpolator = interpolator;
+  } else {
+    throw new Error('Invalid interpolator ' + interpolator);
+  }
+  return this;
+};
+
+/*
+  Darken image pre-resize (1/gamma) and brighten post-resize (gamma).
+  Improves brightness of resized image in non-linear colour spaces.
+*/
+Sharp.prototype.gamma = function(gamma) {
+  if (typeof gamma === 'undefined') {
+    // Default gamma correction of 2.2 (sRGB)
+    this.options.gamma = 2.2;
+  } else if (!Number.isNaN(gamma) && gamma >= 1 && gamma <= 3) {
+    this.options.gamma = gamma;
+  } else {
+    throw new Error('Invalid gamma correction (1.0 to 3.0) ' + gamma);
+  }
+  return this;
+};
+
+/*
+  Enhance output image contrast by stretching its luminance to cover the full dynamic range
+*/
+Sharp.prototype.normalize = function(normalize) {
+  if (process.platform !== 'win32') {
+    this.options.normalize = (typeof normalize === 'boolean') ? normalize : true;
+  } else {
+    console.error('normalize unavailable on win32 platform');
+  }
+  return this;
+};
+Sharp.prototype.normalise = Sharp.prototype.normalize;
+
+/*
+  Convert to greyscale
+*/
+Sharp.prototype.greyscale = function(greyscale) {
+  this.options.greyscale = (typeof greyscale === 'boolean') ? greyscale : true;
+  return this;
+};
+Sharp.prototype.grayscale = Sharp.prototype.greyscale;
+
+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 && quality % 1 === 0) {
+    this.options.quality = quality;
+  } else {
+    throw new Error('Invalid quality (1 to 100) ' + quality);
+  }
+  return this;
+};
+
+/*
+  zlib compression level for PNG output
+*/
+Sharp.prototype.compressionLevel = function(compressionLevel) {
+  if (!Number.isNaN(compressionLevel) && compressionLevel >= 0 && compressionLevel <= 9) {
+    this.options.compressionLevel = compressionLevel;
+  } else {
+    throw new Error('Invalid compressionLevel (0 to 9) ' + compressionLevel);
+  }
+  return this;
+};
+
+/*
+  Disable the use of adaptive row filtering for PNG output - requires libvips 7.42.0+
+*/
+Sharp.prototype.withoutAdaptiveFiltering = function(withoutAdaptiveFiltering) {
+  if (semver.gte(libvipsVersion, '7.42.0')) {
+    this.options.withoutAdaptiveFiltering = (typeof withoutAdaptiveFiltering === 'boolean') ? withoutAdaptiveFiltering : true;
+  } else {
+    console.error('withoutAdaptiveFiltering requires libvips 7.41.0+');
+  }
+  return this;
+};
+
+/*
+  Disable the use of chroma subsampling for JPEG output
+*/
+Sharp.prototype.withoutChromaSubsampling = function(withoutChromaSubsampling) {
+  this.options.withoutChromaSubsampling = (typeof withoutChromaSubsampling === 'boolean') ? withoutChromaSubsampling : true;
+  return this;
+};
+
+/*
+  Apply trellis quantisation to JPEG output - requires libvips 8.0.0+ compiled against mozjpeg 3.0+
+*/
+Sharp.prototype.trellisQuantisation = function(trellisQuantisation) {
+  if (semver.gte(libvipsVersion, '8.0.0')) {
+    this.options.trellisQuantisation = (typeof trellisQuantisation === 'boolean') ? trellisQuantisation : true;
+  } else {
+    console.error('trellisQuantisation requires libvips 8.0.0+');
+  }
+  return this;
+};
+Sharp.prototype.trellisQuantization = Sharp.prototype.trellisQuantisation;
+
+/*
+  Apply overshoot deringing to JPEG output - requires libvips 8.0.0+ compiled against mozjpeg 3.0+
+*/
+Sharp.prototype.overshootDeringing = function(overshootDeringing) {
+  if (semver.gte(libvipsVersion, '8.0.0')) {
+    this.options.overshootDeringing = (typeof overshootDeringing === 'boolean') ? overshootDeringing : true;
+  } else {
+    console.error('overshootDeringing requires libvips 8.0.0+');
+  }
+  return this;
+};
+
+/*
+  Optimise scans in progressive JPEG output - requires libvips 8.0.0+ compiled against mozjpeg 3.0+
+*/
+Sharp.prototype.optimiseScans = function(optimiseScans) {
+  if (semver.gte(libvipsVersion, '8.0.0')) {
+    this.options.optimiseScans = (typeof optimiseScans === 'boolean') ? optimiseScans : true;
+    if (this.options.optimiseScans) {
+      this.progressive();
+    }
+  } else {
+    console.error('optimiseScans requires libvips 8.0.0+');
+  }
+  return this;
+};
+Sharp.prototype.optimizeScans = Sharp.prototype.optimiseScans;
+
+/*
+  Include all metadata (EXIF, XMP, IPTC) from the input image in the output image
+  Optionally provide an Object with attributes to update:
+    orientation: numeric value for EXIF Orientation tag
+*/
+Sharp.prototype.withMetadata = function(withMetadata) {
+  this.options.withMetadata = (typeof withMetadata === 'boolean') ? withMetadata : true;
+  if (typeof withMetadata === 'object') {
+    if ('orientation' in withMetadata) {
+      if (
+        typeof withMetadata.orientation === 'number' &&
+        !Number.isNaN(withMetadata.orientation) &&
+        withMetadata.orientation % 1 === 0 &&
+        withMetadata.orientation >=0 &&
+        withMetadata.orientation <= 7
+      ) {
+        this.options.withMetadataOrientation = withMetadata.orientation;
+      } else {
+        throw new Error('Invalid orientation (0 to 7) ' + withMetadata.orientation);
+      }
+    }
+  }
+  return this;
+};
+
+/*
+  Tile size and overlap for Deep Zoom output
+*/
+Sharp.prototype.tile = function(size, overlap) {
+  // Size of square tiles, in pixels
+  if (typeof size !== 'undefined' && size !== null) {
+    if (!Number.isNaN(size) && size % 1 === 0 && size >= 1 && size <= 8192) {
+      this.options.tileSize = size;
+    } else {
+      throw new Error('Invalid tile size (1 to 8192) ' + size);
+    }
+  }
+  // Overlap of tiles, in pixels
+  if (typeof overlap !== 'undefined' && overlap !== null) {
+    if (!Number.isNaN(overlap) && overlap % 1 === 0 && overlap >=0 && overlap <= 8192) {
+      if (overlap > this.options.tileSize) {
+        throw new Error('Tile overlap ' + overlap + ' cannot be larger than tile size ' + this.options.tileSize);
+      }
+      this.options.tileOverlap = overlap;
+    } else {
+      throw new Error('Invalid tile overlap (0 to 8192) ' + overlap);
+    }
+  }
+  return this;
+};
+
+Sharp.prototype.resize = function(width, height) {
+  if (!width) {
+    this.options.width = -1;
+  } else {
+    if (typeof width === 'number' && !Number.isNaN(width) && width % 1 === 0 && width > 0 && width <= maximum.width) {
+      this.options.width = width;
+    } else {
+      throw new Error('Invalid width (1 to ' + maximum.width + ') ' + width);
+    }
+  }
+  if (!height) {
+    this.options.height = -1;
+  } else {
+    if (typeof height === 'number' && !Number.isNaN(height) && height % 1 === 0 && height > 0 && height <= maximum.height) {
+      this.options.height = height;
+    } else {
+      throw new Error('Invalid height (1 to ' + maximum.height + ') ' + height);
+    }
+  }
+  return this;
+};
+
+/*
+  Limit the total number of pixels for input images
+  Assumes the image dimensions contained in the file header can be trusted
+*/
+Sharp.prototype.limitInputPixels = function(limit) {
+  if (typeof limit === 'number' && !Number.isNaN(limit) && limit % 1 === 0 && limit > 0) {
+    this.options.limitInputPixels = limit;
+  } else {
+    throw new Error('Invalid pixel limit (1 to ' + maximum.pixels + ') ' + limit);
+  }
+  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 BluebirdPromise.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 BluebirdPromise.reject(errOutputIsInput);
+      }
+    } else {
+      this.options.output = output;
+      return this._pipeline(callback);
+    }
+  }
+  return this;
+};
+
+/*
+  Write output to a Buffer
+*/
+Sharp.prototype.toBuffer = function(callback) {
+  return this._pipeline(callback);
+};
+
+/*
+  Force JPEG output
+*/
+Sharp.prototype.jpeg = function() {
+  this.options.output = '__jpeg';
+  return this;
+};
+
+/*
+  Force PNG output
+*/
+Sharp.prototype.png = function() {
+  this.options.output = '__png';
+  return this;
+};
+
+/*
+  Force WebP output
+*/
+Sharp.prototype.webp = function() {
+  this.options.output = '__webp';
+  return this;
+};
+
+/*
+  Force raw, uint8 output
+*/
+Sharp.prototype.raw = function() {
+  var supportsRawOutput = module.exports.format.raw.output;
+  if (supportsRawOutput.file || supportsRawOutput.buffer || supportsRawOutput.stream) {
+    this.options.output = '__raw';
+  } else {
+    console.error('Raw output requires libvips 7.42.0+');
+  }
+  return this;
+};
+
+/*
+  Force output to a given format
+  @param format is either the id as a String or an Object with an 'id' attribute
+*/
+Sharp.prototype.toFormat = function(format) {
+  var id = format;
+  if (typeof format === 'object') {
+    id = format.id;
+  }
+  if (typeof id === 'string' && typeof module.exports.format[id] === 'object' && typeof this[id] === 'function') {
+    this[id]();
+  } else {
+    throw new Error('Unsupported format ' + format);
+  }
+  return this;
+};
+
+/*
+  Used by a Writable Stream to notify that it is ready for data
+*/
+Sharp.prototype._read = function() {
+  if (!this.options.streamOut) {
+    this.options.streamOut = true;
+    this._pipeline();
+  }
+};
+
+/*
+  Invoke the C++ image processing pipeline
+  Supports callback, stream and promise variants
+*/
+Sharp.prototype._pipeline = function(callback) {
+  var that = this;
+  if (typeof callback === 'function') {
+    // output=file/buffer
+    if (this.options.streamIn) {
+      // output=file/buffer, input=stream
+      this.on('finish', function() {
+        sharp.pipeline(that.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.options.streamIn) {
+      // output=stream, input=stream
+      this.on('finish', function() {
+        sharp.pipeline(that.options, function(err, data) {
+          if (err) {
+            that.emit('error', err);
+          } else {
+            that.push(data);
+          }
+          that.push(null);
+        });
+      });
+    } else {
+      // output=stream, input=file/buffer
+      sharp.pipeline(this.options, function(err, data) {
+        if (err) {
+          that.emit('error', err);
+        } else {
+          that.push(data);
+        }
+        that.push(null);
+      });
+    }
+    return this;
+  } else {
+    // output=promise
+    if (this.options.streamIn) {
+      // output=promise, input=stream
+      return new BluebirdPromise(function(resolve, reject) {
+        that.on('finish', function() {
+          sharp.pipeline(that.options, function(err, data) {
+            if (err) {
+              reject(err);
+            } else {
+              resolve(data);
+            }
+          });
+        });
+      });
+    } else {
+      // output=promise, input=file/buffer
+      return new BluebirdPromise(function(resolve, reject) {
+        sharp.pipeline(that.options, function(err, data) {
+          if (err) {
+            reject(err);
+          } else {
+            resolve(data);
+          }
+        });
+      });
+    }
+  }
+};
+
+/*
+  Reads the image header and returns metadata
+  Supports callback, stream and promise variants
+*/
+Sharp.prototype.metadata = function(callback) {
+  var that = this;
+  if (typeof callback === 'function') {
+    if (this.options.streamIn) {
+      this.on('finish', function() {
+        sharp.metadata(that.options, callback);
+      });
+    } else {
+      sharp.metadata(this.options, callback);
+    }
+    return this;
+  } else {
+    if (this.options.streamIn) {
+      return new BluebirdPromise(function(resolve, reject) {
+        that.on('finish', function() {
+          sharp.metadata(that.options, function(err, metadata) {
+            if (err) {
+              reject(err);
+            } else {
+              resolve(metadata);
+            }
+          });
+        });
+      });
+    } else {
+      return new BluebirdPromise(function(resolve, reject) {
+        sharp.metadata(that.options, function(err, metadata) {
+          if (err) {
+            reject(err);
+          } else {
+            resolve(metadata);
+          }
+        });
+      });
+    }
+  }
+};
+
+/*
+  Clone new instance using existing options.
+  Cloned instances share the same input.
+*/
+Sharp.prototype.clone = function() {
+  // Clone existing options
+  var clone = new Sharp();
+  util._extend(clone.options, this.options);
+  clone.streamIn = false;
+  // Pass 'finish' event to clone for Stream-based input
+  this.on('finish', function() {
+    // Clone inherits input data
+    clone.options.bufferIn = this.options.bufferIn;
+    clone.emit('finish');
+  });
+  return clone;
+};
+
+/*
+  Get and set cache memory and item limits
+*/
+module.exports.cache = function(memory, items) {
+  if (typeof memory !== 'number' || Number.isNaN(memory)) {
+    memory = null;
+  }
+  if (typeof items !== 'number' || Number.isNaN(items)) {
+    items = null;
+  }
+  return sharp.cache(memory, items);
+};
+
+/*
+  Get and set size of thread pool
+*/
+module.exports.concurrency = function(concurrency) {
+  if (typeof concurrency !== 'number' || Number.isNaN(concurrency)) {
+    concurrency = null;
+  }
+  return sharp.concurrency(concurrency);
+};
+
+/*
+  Get internal counters
+*/
+module.exports.counters = function() {
+  return sharp.counters();
+};
+
+/*
+  Get the version of the libvips library
+*/
+module.exports.libvipsVersion = function() {
+  return libvipsVersion;
+};

mkdocs.yml

@@ -0,0 +1,17 @@
+site_name: sharp
+site_url: http://sharp.dimens.io/
+repo_url: https://github.com/lovell/sharp
+site_description: The fastest Node.js module for resizing JPEG, PNG, WebP and TIFF images. Uses the libvips library.
+copyright: <a href="https://dimens.io/">dimens.io</a>
+google_analytics: ['UA-13034748-12', 'sharp.dimens.io']
+theme: readthedocs
+markdown_extensions:
+  - toc:
+      permalink: True
+dev_addr: 0.0.0.0:10101
+pages:
+  - Home: index.md
+  - Installation: install.md
+  - API: api.md
+  - Performance: performance.md
+  - Changelog: changelog.md

package.json

@@ -1,10 +1,31 @@
 {
   "name": "sharp",
-  "version": "0.0.8",
-  "author": "Lovell Fuller",
-  "description": "High performance module to resize JPEG and PNG images using the libvips image processing library",
+  "version": "0.11.2",
+  "author": "Lovell Fuller <npm@lovell.info>",
+  "contributors": [
+    "Pierre Inglebert <pierre.inglebert@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>"
+  ],
+  "description": "High performance Node.js module to resize JPEG, PNG, WebP and TIFF images using the libvips library",
   "scripts": {
-    "test": "node tests/perf.js"
+    "clean": "rm -rf test/fixtures/output.*",
+    "test": "VIPS_WARNING=0 node ./node_modules/istanbul/lib/cli.js cover ./node_modules/mocha/bin/_mocha -- --slow=5000 --timeout=20000 ./test/unit/*.js",
+    "test-clean": "npm run clean && npm install && npm test",
+    "test-leak": "./test/leak/leak.sh",
+    "test-win32-node": "node ./node_modules/mocha/bin/mocha --slow=5000 --timeout=30000 ./test/unit/*.js",
+    "test-win32-iojs": "iojs ./node_modules/mocha/bin/mocha --slow=5000 --timeout=30000 ./test/unit/*.js"
   },
   "main": "index.js",
   "repository": {
@@ -14,24 +35,35 @@
   "keywords": [
     "jpeg",
     "png",
+    "webp",
+    "tiff",
+    "dzi",
     "resize",
     "thumbnail",
-    "sharpen",
     "crop",
-    "embed",
     "libvips",
-    "fast",
-    "buffer"
+    "vips"
   ],
-  "devDependencies": {
-    "imagemagick": "*",
-    "gm": "*",
-    "epeg": "*",
-    "async": "*",
-    "benchmark": "*"
+  "dependencies": {
+    "bluebird": "^2.9.34",
+    "color": "^0.10.1",
+    "nan": "^2.0.8",
+    "semver": "^5.0.1"
   },
-  "license": "Apache 2.0",
+  "devDependencies": {
+    "async": "^1.4.2",
+    "coveralls": "^2.11.4",
+    "exif-reader": "1.0.0",
+    "icc": "^0.0.2",
+    "istanbul": "^0.3.18",
+    "mocha": "^2.2.5",
+    "mocha-jshint": "^2.2.3",
+    "node-cpplint": "^0.4.0",
+    "rimraf": "^2.4.2",
+    "bufferutil": "^1.2.1"
+  },
+  "license": "Apache-2.0",
   "engines": {
-    "node": ">=0.8"
+    "node": ">=0.10"
   }
-}
+}

preinstall.sh

@@ -0,0 +1,324 @@
+#!/bin/sh
+
+# Ensures libvips is installed and attempts to install it if not
+# Currently supports:
+# * Debian Linux
+#   * Debian 7, 8
+#   * Ubuntu 12.04, 14.04, 14.10, 15.04
+#   * Mint 13, 17
+# * Red Hat Linux
+#   * RHEL/Centos/Scientific 6, 7
+#   * Fedora 21, 22
+#   * Amazon Linux 2014.09, 2015.03
+
+vips_version_minimum=7.40.0
+vips_version_latest_major_minor=8.0
+vips_version_latest_patch=2
+
+openslide_version_minimum=3.4.0
+openslide_version_latest_major_minor=3.4
+openslide_version_latest_patch=1
+
+install_libvips_from_source() {
+  echo "Compiling libvips $vips_version_latest_major_minor.$vips_version_latest_patch from source"
+  curl -O http://www.vips.ecs.soton.ac.uk/supported/$vips_version_latest_major_minor/vips-$vips_version_latest_major_minor.$vips_version_latest_patch.tar.gz
+  tar zvxf vips-$vips_version_latest_major_minor.$vips_version_latest_patch.tar.gz
+  cd vips-$vips_version_latest_major_minor.$vips_version_latest_patch
+  ./configure --disable-debug --disable-docs --disable-static --disable-introspection --enable-cxx=yes --without-python --without-orc --without-fftw $1
+  make
+  make install
+  cd ..
+  rm -rf vips-$vips_version_latest_major_minor.$vips_version_latest_patch
+  rm vips-$vips_version_latest_major_minor.$vips_version_latest_patch.tar.gz
+  ldconfig
+  echo "Installed libvips $vips_version_latest_major_minor.$vips_version_latest_patch"
+}
+
+install_libopenslide_from_source() {
+  echo "Compiling openslide $openslide_version_latest_major_minor.$openslide_version_latest_patch from source"
+  curl -O -L https://github.com/openslide/openslide/releases/download/v$openslide_version_latest_major_minor.$openslide_version_latest_patch/openslide-$openslide_version_latest_major_minor.$openslide_version_latest_patch.tar.gz
+  tar xzvf openslide-$openslide_version_latest_major_minor.$openslide_version_latest_patch.tar.gz
+  cd openslide-$openslide_version_latest_major_minor.$openslide_version_latest_patch
+  PKG_CONFIG_PATH=$pkg_config_path ./configure $1
+  make
+  make install
+  cd ..
+  rm -rf openslide-$openslide_version_latest_major_minor.$openslide_version_latest_patch
+  rm openslide-$openslide_version_latest_major_minor.$openslide_version_latest_patch.tar.gz
+  ldconfig
+  echo "Installed libopenslide $openslide_version_latest_major_minor.$openslide_version_latest_patch"
+}
+
+sorry() {
+  echo "Sorry, I don't yet know how to install lib$1 on $2"
+  exit 1
+}
+
+pkg_config_path="$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig:/usr/lib/pkgconfig"
+
+check_if_library_exists() {
+  PKG_CONFIG_PATH=$pkg_config_path pkg-config --exists $1
+  if [ $? -eq 0 ]; then
+    version_found=$(PKG_CONFIG_PATH=$pkg_config_path pkg-config --modversion $1)
+    PKG_CONFIG_PATH=$pkg_config_path pkg-config --atleast-version=$2 $1
+    if [ $? -eq 0 ]; then
+      # Found suitable version of libvips
+      echo "Found lib$1 $version_found"
+      return 1
+    fi
+    echo "Found lib$1 $version_found but require $2"
+  else
+    echo "Could not find lib$1 using a PKG_CONFIG_PATH of '$pkg_config_path'"
+  fi
+  return 0
+}
+
+enable_openslide=0
+# Is libvips already installed, and is it at least the minimum required version?
+if [ $# -eq 1 ]; then
+  if [ "$1" = "--with-openslide" ]; then
+    echo "Installing vips with openslide support"
+    enable_openslide=1
+  else
+    echo "Sorry, $1 is not supported. Did you mean --with-openslide?"
+    exit 1
+  fi
+fi
+
+if ! type pkg-config >/dev/null; then
+  sorry "vips" "a system without pkg-config"
+fi
+
+openslide_exists=0
+if [ $enable_openslide -eq 1 ]; then
+  check_if_library_exists "openslide" "$openslide_version_minimum"
+  openslide_exists=$?
+fi
+
+check_if_library_exists "vips" "$vips_version_minimum"
+vips_exists=$?
+if [ $vips_exists -eq 1 ] && [ $enable_openslide -eq 1 ]; then
+  if [ $openslide_exists -eq 1 ]; then
+    # Check if vips compiled with openslide support
+    vips_with_openslide=`vips list classes | grep -i opensli`
+    if [ -z $vips_with_openslide ]; then
+      echo "Vips compiled without openslide support."
+    else
+      exit 0
+    fi
+  fi
+elif [ $vips_exists -eq 1 ] && [ $enable_openslide -eq 0 ]; then
+  exit 0
+fi
+
+# Verify root/sudo access
+if [ "$(id -u)" -ne "0" ]; then
+  echo "Sorry, I need root/sudo access to continue"
+  exit 1
+fi
+
+# OS-specific installations of libopenslide follows
+# Either openslide does not exist, or vips is installed without openslide support
+if [ $enable_openslide -eq 1 ] && [ -z $vips_with_openslide ] && [ $openslide_exists -eq 0 ]; then
+  if [ -f /etc/debian_version ]; then
+    # Debian Linux
+    DISTRO=$(lsb_release -c -s)
+    echo "Detected Debian Linux '$DISTRO'"
+    case "$DISTRO" in
+      jessie|vivid)
+        # Debian 8, Ubuntu 15
+        echo "Installing libopenslide via apt-get"
+        apt-get install -y libopenslide-dev
+        ;;
+      trusty|utopic|qiana|rebecca|rafaela)
+        # Ubuntu 14, Mint 17
+        echo "Installing libopenslide dependencies via apt-get"
+        apt-get install -y automake build-essential curl zlib1g-dev libopenjpeg-dev libpng12-dev libjpeg-dev libtiff5-dev libgdk-pixbuf2.0-dev libxml2-dev libsqlite3-dev libcairo2-dev libglib2.0-dev sqlite3 libsqlite3-dev
+        install_libopenslide_from_source
+        ;;
+      precise|wheezy|maya)
+        # Debian 7, Ubuntu 12.04, Mint 13
+        echo "Installing libopenslide dependencies via apt-get"
+        apt-get install -y automake build-essential curl zlib1g-dev libopenjpeg-dev libpng12-dev libjpeg-dev libtiff5-dev libgdk-pixbuf2.0-dev libxml2-dev libsqlite3-dev libcairo2-dev libglib2.0-dev sqlite3 libsqlite3-dev
+        install_libopenslide_from_source
+        ;;
+      *)
+        # Unsupported Debian-based OS
+        sorry "openslide" "Debian-based $DISTRO"
+        ;;
+    esac
+  elif [ -f /etc/redhat-release ]; then
+    # Red Hat Linux
+    RELEASE=$(cat /etc/redhat-release)
+    echo "Detected Red Hat Linux '$RELEASE'"
+    case $RELEASE in
+      "Red Hat Enterprise Linux release 7."*|"CentOS Linux release 7."*|"Scientific Linux release 7."*)
+        # RHEL/CentOS 7
+        echo "Installing libopenslide dependencies via yum"
+        yum groupinstall -y "Development Tools"
+        yum install -y tar curl libpng-devel libjpeg-devel libxml2-devel zlib-devel openjpeg-devel libtiff-devel gdk-pixbuf2-devel sqlite-devel cairo-devel glib2-devel
+        install_libopenslide_from_source "--prefix=/usr"
+        ;;
+      "Red Hat Enterprise Linux release 6."*|"CentOS release 6."*|"Scientific Linux release 6."*)
+        # RHEL/CentOS 6
+        echo "Installing libopenslide dependencies via yum"
+        yum groupinstall -y "Development Tools"
+        yum install -y tar curl libpng-devel libjpeg-devel libxml2-devel zlib-devel openjpeg-devel libtiff-devel gdk-pixbuf2-devel sqlite-devel cairo-devel glib2-devel
+        install_libopenslide_from_source "--prefix=/usr"
+        ;;
+      "Fedora release 21 "*|"Fedora release 22 "*)
+        # Fedora 21, 22
+        echo "Installing libopenslide via yum"
+        yum install -y openslide-devel
+        ;;
+      *)
+        # Unsupported RHEL-based OS
+        sorry "openslide" "$RELEASE"
+        ;;
+    esac
+  elif [ -f /etc/os-release ]; then
+    RELEASE=$(cat /etc/os-release | grep VERSION)
+    echo "Detected OpenSuse Linux '$RELEASE'"
+    case $RELEASE in
+      *"13.2"*)
+      echo "Installing libopenslide via zypper"
+      zypper --gpg-auto-import-keys install -y libopenslide-devel
+      ;;
+    esac
+  elif [ -f /etc/SuSE-brand ]; then
+    RELEASE=$(cat /etc/SuSE-brand | grep VERSION)
+    echo "Detected OpenSuse Linux '$RELEASE'"
+    case $RELEASE in
+      *"13.1")
+      echo "Installing libopenslide dependencies via zypper"
+      zypper --gpg-auto-import-keys install -y --type pattern devel_basis
+      zypper --gpg-auto-import-keys install -y tar curl libpng16-devel libjpeg-turbo libjpeg8-devel libxml2-devel zlib-devel openjpeg-devel libtiff-devel libgdk_pixbuf-2_0-0 sqlite3-devel cairo-devel glib2-devel
+      install_libopenslide_from_source
+      ;;
+    esac
+  else
+    # Unsupported OS
+    sorry "openslide" "$(uname -a)"
+  fi
+fi
+
+# OS-specific installations of libvips follows
+
+if [ -f /etc/debian_version ]; then
+  # Debian Linux
+  DISTRO=$(lsb_release -c -s)
+  echo "Detected Debian Linux '$DISTRO'"
+  case "$DISTRO" in
+    jessie|vivid)
+      # Debian 8, Ubuntu 15
+      if [ $enable_openslide -eq 1 ]; then
+        echo "Recompiling vips with openslide support"
+        install_libvips_from_source
+      else
+        echo "Installing libvips via apt-get"
+        apt-get install -y libvips-dev libgsf-1-dev
+      fi
+      ;;
+    trusty|utopic|qiana|rebecca|rafaela)
+      # Ubuntu 14, Mint 17
+      echo "Installing libvips dependencies via apt-get"
+      apt-get install -y automake build-essential gobject-introspection gtk-doc-tools libglib2.0-dev libjpeg-dev libpng12-dev libwebp-dev libtiff5-dev libexif-dev libgsf-1-dev liblcms2-dev libxml2-dev swig libmagickcore-dev curl
+      install_libvips_from_source
+      ;;
+    precise|wheezy|maya)
+      # Debian 7, Ubuntu 12.04, Mint 13
+      echo "Installing libvips dependencies via apt-get"
+      add-apt-repository -y ppa:lyrasis/precise-backports
+      apt-get update
+      apt-get install -y automake build-essential gobject-introspection gtk-doc-tools libglib2.0-dev libjpeg-dev libpng12-dev libwebp-dev libtiff4-dev libexif-dev libgsf-1-dev liblcms2-dev libxml2-dev swig libmagickcore-dev curl
+      install_libvips_from_source
+      ;;
+    *)
+      # Unsupported Debian-based OS
+      sorry "vips" "Debian-based $DISTRO"
+      ;;
+  esac
+elif [ -f /etc/redhat-release ]; then
+  # Red Hat Linux
+  RELEASE=$(cat /etc/redhat-release)
+  echo "Detected Red Hat Linux '$RELEASE'"
+  case $RELEASE in
+    "Red Hat Enterprise Linux release 7."*|"CentOS Linux release 7."*|"Scientific Linux release 7."*)
+      # RHEL/CentOS 7
+      echo "Installing libvips dependencies via yum"
+      yum groupinstall -y "Development Tools"
+      yum install -y gtk-doc libxml2-devel libjpeg-turbo-devel libpng-devel libtiff-devel libexif-devel libgsf-devel lcms-devel ImageMagick-devel gobject-introspection-devel libwebp-devel curl
+      install_libvips_from_source "--prefix=/usr"
+      ;;
+    "Red Hat Enterprise Linux release 6."*|"CentOS release 6."*|"Scientific Linux release 6."*)
+      # RHEL/CentOS 6
+      echo "Installing libvips dependencies via yum"
+      yum groupinstall -y "Development Tools"
+      yum install -y gtk-doc libxml2-devel libjpeg-turbo-devel libpng-devel libtiff-devel libexif-devel libgsf-devel lcms-devel ImageMagick-devel curl
+      yum install -y http://li.nux.ro/download/nux/dextop/el6/x86_64/nux-dextop-release-0-2.el6.nux.noarch.rpm
+      yum install -y --enablerepo=nux-dextop gobject-introspection-devel
+      yum install -y http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
+      yum install -y --enablerepo=remi libwebp-devel
+      install_libvips_from_source "--prefix=/usr"
+      ;;
+    "Fedora release 21 "*|"Fedora release 22 "*)
+      # Fedora 21, 22
+      if [ $enable_openslide -eq 1 ]; then
+        echo "Installing libvips dependencies via yum"
+        yum groupinstall -y "Development Tools"
+        yum install -y gcc-c++ gtk-doc libxml2-devel libjpeg-turbo-devel libpng-devel libtiff-devel libexif-devel lcms-devel ImageMagick-devel gobject-introspection-devel libwebp-devel curl
+        echo "Compiling vips with openslide support"
+        install_libvips_from_source "--prefix=/usr"
+      else
+        echo "Installing libvips via yum"
+        yum install -y vips-devel
+      fi
+      ;;
+    *)
+      # Unsupported RHEL-based OS
+      sorry "vips" "$RELEASE"
+      ;;
+  esac
+elif [ -f /etc/system-release ]; then
+  # Probably Amazon Linux
+  RELEASE=$(cat /etc/system-release)
+  case $RELEASE in
+    "Amazon Linux AMI release 2014.09"|"Amazon Linux AMI release 2015.03")
+      # Amazon Linux
+      echo "Detected '$RELEASE'"
+      echo "Installing libvips dependencies via yum"
+      yum groupinstall -y "Development Tools"
+      yum install -y gtk-doc libxml2-devel libjpeg-turbo-devel libpng-devel libtiff-devel libexif-devel libgsf-devel lcms-devel ImageMagick-devel gobject-introspection-devel libwebp-devel curl
+      install_libvips_from_source "--prefix=/usr"
+      ;;
+    *)
+      # Unsupported Amazon Linux version
+      sorry "vips" "$RELEASE"
+      ;;
+  esac
+elif [ -f /etc/os-release ]; then
+  RELEASE=$(cat /etc/os-release | grep VERSION)
+  echo "Detected OpenSuse Linux '$RELEASE'"
+  case $RELEASE in
+    *"13.2"*)
+    echo "Installing libvips dependencies via zypper"
+    zypper --gpg-auto-import-keys install -y --type pattern devel_basis
+    zypper --gpg-auto-import-keys install -y tar curl gtk-doc libxml2-devel libjpeg-turbo libjpeg8-devel libpng16-devel libtiff-devel libexif-devel liblcms2-devel ImageMagick-devel gobject-introspection-devel libwebp-devel
+    install_libvips_from_source
+    ;;
+  esac
+elif [ -f /etc/SuSE-brand ]; then
+  RELEASE=$(cat /etc/SuSE-brand | grep VERSION)
+  echo "Detected OpenSuse Linux '$RELEASE'"
+  case $RELEASE in
+    *"13.1")
+    echo "Installing libvips dependencies via zypper"
+    zypper --gpg-auto-import-keys install -y --type pattern devel_basis
+    zypper --gpg-auto-import-keys install -y tar curl gtk-doc libxml2-devel libjpeg-turbo libjpeg8-devel libpng16-devel libtiff-devel libexif-devel liblcms2-devel ImageMagick-devel gobject-introspection-devel libwebp-devel
+    install_libvips_from_source
+    ;;
+  esac
+else
+  # Unsupported OS
+  sorry "vips" "$(uname -a)"
+fi

src/common.cc

@@ -0,0 +1,184 @@
+#include <cstdlib>
+#include <string>
+#include <string.h>
+#include <vips/vips.h>
+
+#include "common.h"
+
+// Verify platform and compiler compatibility
+
+#if (VIPS_MAJOR_VERSION < 7 || (VIPS_MAJOR_VERSION == 7 && VIPS_MINOR_VERSION < 40))
+#error libvips version 7.40.0+ required - see http://sharp.dimens.io/page/install
+#endif
+
+#ifdef _WIN64
+#error Windows 64-bit is currently unsupported - see http://sharp.dimens.io/page/install#windows
+#endif
+
+#if ((!defined(__clang__)) && defined(__GNUC__) && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)))
+#error GCC version 4.6+ is required for C++11 features - see http://sharp.dimens.io/page/install#prerequisites
+#endif
+
+#if (defined(__clang__) && defined(__has_feature))
+#if (!__has_feature(cxx_range_for))
+#error clang version 3.0+ is required for C++11 features - see http://sharp.dimens.io/page/install#prerequisites
+#endif
+#endif
+
+#define EXIF_IFD0_ORIENTATION "exif-ifd0-Orientation"
+
+namespace sharp {
+
+  // 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 IsTiff(std::string const &str) {
+    return EndsWith(str, ".tif") || EndsWith(str, ".tiff") || EndsWith(str, ".TIF") || EndsWith(str, ".TIFF");
+  }
+  bool IsDz(std::string const &str) {
+    return EndsWith(str, ".dzi") || EndsWith(str, ".DZI");
+  }
+
+  /*
+    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 != NULL) {
+      std::string loader = load;
+      if (EndsWith(loader, "JpegBuffer")) {
+        imageType = ImageType::JPEG;
+      } else if (EndsWith(loader, "PngBuffer")) {
+        imageType = ImageType::PNG;
+      } else if (EndsWith(loader, "WebpBuffer")) {
+        imageType = ImageType::WEBP;
+      } else if (EndsWith(loader, "TiffBuffer")) {
+        imageType = ImageType::TIFF;
+      } else if (EndsWith(loader, "MagickBuffer")) {
+        imageType = ImageType::MAGICK;
+      }
+    }
+    return imageType;
+  }
+
+  /*
+    Initialise and return a VipsImage from a buffer. Supports JPEG, PNG, WebP and TIFF.
+  */
+  VipsImage* InitImage(void *buffer, size_t const length, VipsAccess const access) {
+    return vips_image_new_from_buffer(buffer, length, NULL, "access", access, NULL);
+  }
+
+  /*
+    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 != NULL) {
+      std::string loader = load;
+      if (EndsWith(loader, "JpegFile")) {
+        imageType = ImageType::JPEG;
+      } else if (EndsWith(loader, "Png")) {
+        imageType = ImageType::PNG;
+      } else if (EndsWith(loader, "WebpFile")) {
+        imageType = ImageType::WEBP;
+      } else if (EndsWith(loader, "Openslide")) {
+        imageType = ImageType::OPENSLIDE;
+      } else if (EndsWith(loader, "TiffFile")) {
+        imageType = ImageType::TIFF;
+      } else if (EndsWith(loader, "Magick") || EndsWith(loader, "MagickFile")) {
+        imageType = ImageType::MAGICK;
+      }
+    }
+    return imageType;
+  }
+
+  /*
+    Initialise and return a VipsImage from a file.
+  */
+  VipsImage* InitImage(char const *file, VipsAccess const access) {
+    return vips_image_new_from_file(file, "access", access, NULL);
+  }
+
+  /*
+    Does this image have an embedded profile?
+  */
+  bool HasProfile(VipsImage *image) {
+    return (vips_image_get_typeof(image, 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(VipsImage *image) {
+    return (
+      (image->Bands == 2 && image->Type == VIPS_INTERPRETATION_B_W) ||
+      (image->Bands == 4 && image->Type != VIPS_INTERPRETATION_CMYK) ||
+      (image->Bands == 5 && image->Type == VIPS_INTERPRETATION_CMYK)
+    );
+  }
+
+  /*
+    Get EXIF Orientation of image, if any.
+  */
+  int ExifOrientation(VipsImage const *image) {
+    int orientation = 0;
+    const char *exif;
+    if (
+      vips_image_get_typeof(image, EXIF_IFD0_ORIENTATION) != 0 &&
+      !vips_image_get_string(image, EXIF_IFD0_ORIENTATION, &exif)
+    ) {
+      orientation = atoi(&exif[0]);
+    }
+    return orientation;
+  }
+
+  /*
+    Set EXIF Orientation of image.
+  */
+  void SetExifOrientation(VipsImage *image, int const orientation) {
+    char exif[3];
+    g_snprintf(exif, sizeof(exif), "%d", orientation);
+    vips_image_set_string(image, EXIF_IFD0_ORIENTATION, exif);
+  }
+
+  /*
+    Remove EXIF Orientation from image.
+  */
+  void RemoveExifOrientation(VipsImage *image) {
+    SetExifOrientation(image, 0);
+  }
+
+  /*
+    Returns the window size for the named interpolator. For example,
+    a window size of 3 means a 3x3 pixel grid is used for the calculation.
+  */
+  int InterpolatorWindowSize(char const *name) {
+    VipsInterpolate *interpolator = vips_interpolate_new(name);
+    if (interpolator == NULL) {
+      return -1;
+    }
+    int window_size = vips_interpolate_get_window_size(interpolator);
+    g_object_unref(interpolator);
+    return window_size;
+  }
+
+} // namespace sharp

src/common.h

@@ -0,0 +1,85 @@
+#ifndef SRC_COMMON_H_
+#define SRC_COMMON_H_
+
+#include <string>
+
+namespace sharp {
+
+  enum class ImageType {
+    UNKNOWN,
+    JPEG,
+    PNG,
+    WEBP,
+    TIFF,
+    MAGICK,
+    OPENSLIDE
+  };
+
+  // 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 IsTiff(std::string const &str);
+  bool IsDz(std::string const &str);
+
+  /*
+    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);
+
+  /*
+    Initialise and return a VipsImage from a buffer. Supports JPEG, PNG, WebP and TIFF.
+  */
+  VipsImage* InitImage(void *buffer, size_t const length, VipsAccess const access);
+
+  /*
+    Initialise and return a VipsImage from a file.
+  */
+  VipsImage* InitImage(char const *file, VipsAccess const access);
+
+  /*
+    Does this image have an embedded profile?
+  */
+  bool HasProfile(VipsImage *image);
+
+  /*
+    Does this image have an alpha channel?
+    Uses colour space interpretation with number of channels to guess this.
+  */
+  bool HasAlpha(VipsImage *image);
+
+  /*
+    Get EXIF Orientation of image, if any.
+  */
+  int ExifOrientation(VipsImage const *image);
+
+  /*
+    Set EXIF Orientation of image.
+  */
+  void SetExifOrientation(VipsImage *image, int const orientation);
+
+  /*
+    Remove EXIF Orientation from image.
+  */
+  void RemoveExifOrientation(VipsImage *image);
+
+  /*
+    Returns the window size for the named interpolator. For example,
+    a window size of 3 means a 3x3 pixel grid is used for the calculation.
+  */
+  int InterpolatorWindowSize(char const *name);
+
+}  // namespace sharp
+
+#endif  // SRC_COMMON_H_

src/metadata.cc

@@ -0,0 +1,232 @@
+#include <node.h>
+#include <vips/vips.h>
+
+#include "nan.h"
+
+#include "common.h"
+#include "metadata.h"
+
+using v8::Handle;
+using v8::Local;
+using v8::Value;
+using v8::Object;
+using v8::Number;
+using v8::String;
+using v8::Boolean;
+using v8::Function;
+using v8::Exception;
+
+using Nan::AsyncQueueWorker;
+using Nan::AsyncWorker;
+using Nan::Callback;
+using Nan::HandleScope;
+using Nan::Utf8String;
+using Nan::Has;
+using Nan::Get;
+using Nan::Set;
+using Nan::New;
+using Nan::NewBuffer;
+using Nan::Null;
+using Nan::Error;
+
+using sharp::ImageType;
+using sharp::DetermineImageType;
+using sharp::InitImage;
+using sharp::HasProfile;
+using sharp::HasAlpha;
+using sharp::ExifOrientation;
+using sharp::counterQueue;
+
+struct MetadataBaton {
+  // Input
+  std::string fileIn;
+  char *bufferIn;
+  size_t bufferInLength;
+  // Output
+  std::string format;
+  int width;
+  int height;
+  std::string space;
+  int channels;
+  bool hasProfile;
+  bool hasAlpha;
+  int orientation;
+  char *exif;
+  size_t exifLength;
+  char *icc;
+  size_t iccLength;
+  std::string err;
+
+  MetadataBaton():
+    bufferInLength(0),
+    orientation(0),
+    exifLength(0),
+    iccLength(0) {}
+};
+
+/*
+  Delete input char[] buffer and notify V8 of memory deallocation
+  Used as the callback function for the "postclose" signal
+*/
+static void DeleteBuffer(VipsObject *object, char *buffer) {
+  if (buffer != NULL) {
+    delete[] buffer;
+  }
+}
+
+class MetadataWorker : public AsyncWorker {
+
+ public:
+  MetadataWorker(Callback *callback, MetadataBaton *baton) : AsyncWorker(callback), baton(baton) {}
+  ~MetadataWorker() {}
+
+  void Execute() {
+    // Decrement queued task counter
+    g_atomic_int_dec_and_test(&counterQueue);
+
+    ImageType imageType = ImageType::UNKNOWN;
+    VipsImage *image = NULL;
+    if (baton->bufferInLength > 0) {
+      // From buffer
+      imageType = DetermineImageType(baton->bufferIn, baton->bufferInLength);
+      if (imageType != ImageType::UNKNOWN) {
+        image = InitImage(baton->bufferIn, baton->bufferInLength, VIPS_ACCESS_RANDOM);
+        if (image != NULL) {
+          // Listen for "postclose" signal to delete input buffer
+          g_signal_connect(image, "postclose", G_CALLBACK(DeleteBuffer), baton->bufferIn);
+        } else {
+          (baton->err).append("Input buffer has corrupt header");
+          imageType = ImageType::UNKNOWN;
+          DeleteBuffer(NULL, baton->bufferIn);
+        }
+      } else {
+        (baton->err).append("Input buffer contains unsupported image format");
+        DeleteBuffer(NULL, baton->bufferIn);
+      }
+    } else {
+      // From file
+      imageType = DetermineImageType(baton->fileIn.c_str());
+      if (imageType != ImageType::UNKNOWN) {
+        image = InitImage(baton->fileIn.c_str(), VIPS_ACCESS_RANDOM);
+        if (image == NULL) {
+          (baton->err).append("Input file has corrupt header");
+          imageType = ImageType::UNKNOWN;
+        }
+      } else {
+        (baton->err).append("Input file is of an unsupported image format");
+      }
+    }
+    if (image != NULL && imageType != ImageType::UNKNOWN) {
+      // Image type
+      switch (imageType) {
+        case ImageType::JPEG: baton->format = "jpeg"; break;
+        case ImageType::PNG: baton->format = "png"; break;
+        case ImageType::WEBP: baton->format = "webp"; break;
+        case ImageType::TIFF: baton->format = "tiff"; break;
+        case ImageType::MAGICK: baton->format = "magick"; break;
+        case ImageType::OPENSLIDE: baton->format = "openslide"; break;
+        case ImageType::UNKNOWN: break;
+      }
+      // VipsImage attributes
+      baton->width = image->Xsize;
+      baton->height = image->Ysize;
+      baton->space = vips_enum_nick(VIPS_TYPE_INTERPRETATION, image->Type);
+      baton->channels = image->Bands;
+      baton->hasProfile = HasProfile(image);
+      // Derived attributes
+      baton->hasAlpha = HasAlpha(image);
+      baton->orientation = ExifOrientation(image);
+      // EXIF
+      if (vips_image_get_typeof(image, VIPS_META_EXIF_NAME) == VIPS_TYPE_BLOB) {
+        void* exif;
+        size_t exifLength;
+        if (!vips_image_get_blob(image, VIPS_META_EXIF_NAME, &exif, &exifLength)) {
+          baton->exifLength = exifLength;
+          baton->exif = static_cast<char*>(malloc(exifLength));
+          memcpy(baton->exif, exif, exifLength);
+        }
+      }
+      // ICC profile
+      if (vips_image_get_typeof(image, VIPS_META_ICC_NAME) == VIPS_TYPE_BLOB) {
+        void* icc;
+        size_t iccLength;
+        if (!vips_image_get_blob(image, VIPS_META_ICC_NAME, &icc, &iccLength)) {
+          baton->iccLength = iccLength;
+          baton->icc = static_cast<char*>(malloc(iccLength));
+          memcpy(baton->icc, icc, iccLength);
+        }
+      }
+      // Drop image reference
+      g_object_unref(image);
+    }
+    // Clean up
+    vips_error_clear();
+    vips_thread_shutdown();
+  }
+
+  void HandleOKCallback () {
+    HandleScope();
+
+    Local<Value> argv[2] = { Null(), Null() };
+    if (!baton->err.empty()) {
+      // Error
+      argv[0] = Error(baton->err.c_str());
+    } else {
+      // Metadata Object
+      Local<Object> info = New<Object>();
+      Set(info, New("format").ToLocalChecked(), New<String>(baton->format).ToLocalChecked());
+      Set(info, New("width").ToLocalChecked(), New<Number>(baton->width));
+      Set(info, New("height").ToLocalChecked(), New<Number>(baton->height));
+      Set(info, New("space").ToLocalChecked(), New<String>(baton->space).ToLocalChecked());
+      Set(info, New("channels").ToLocalChecked(), New<Number>(baton->channels));
+      Set(info, New("hasProfile").ToLocalChecked(), New<Boolean>(baton->hasProfile));
+      Set(info, New("hasAlpha").ToLocalChecked(), New<Boolean>(baton->hasAlpha));
+      if (baton->orientation > 0) {
+        Set(info, New("orientation").ToLocalChecked(), New<Number>(baton->orientation));
+      }
+      if (baton->exifLength > 0) {
+        Set(info, New("exif").ToLocalChecked(), NewBuffer(baton->exif, baton->exifLength).ToLocalChecked());
+      }
+      if (baton->iccLength > 0) {
+        Set(info, New("icc").ToLocalChecked(), NewBuffer(baton->icc, baton->iccLength).ToLocalChecked());
+      }
+      argv[1] = info;
+    }
+    delete baton;
+
+    // Return to JavaScript
+    callback->Call(2, argv);
+  }
+
+ private:
+  MetadataBaton* baton;
+};
+
+/*
+  metadata(options, callback)
+*/
+NAN_METHOD(metadata) {
+  HandleScope();
+
+  // V8 objects are converted to non-V8 types held in the baton struct
+  MetadataBaton *baton = new MetadataBaton;
+  Local<Object> options = info[0].As<Object>();
+
+  // Input filename
+  baton->fileIn = *Utf8String(Get(options, New("fileIn").ToLocalChecked()).ToLocalChecked());
+  // Input Buffer object
+  if (node::Buffer::HasInstance(Get(options, New("bufferIn").ToLocalChecked()).ToLocalChecked())) {
+    Local<Object> buffer = Get(options, New("bufferIn").ToLocalChecked()).ToLocalChecked().As<Object>();
+    // Take a copy of the input Buffer to avoid problems with V8 heap compaction
+    baton->bufferInLength = node::Buffer::Length(buffer);
+    baton->bufferIn = new char[baton->bufferInLength];
+    memcpy(baton->bufferIn, node::Buffer::Data(buffer), baton->bufferInLength);
+  }
+
+  // Join queue for worker thread
+  Callback *callback = new Callback(info[1].As<Function>());
+  AsyncQueueWorker(new MetadataWorker(callback, baton));
+
+  // Increment queued task counter
+  g_atomic_int_inc(&counterQueue);
+}

src/metadata.h

@@ -0,0 +1,8 @@
+#ifndef SRC_METADATA_H_
+#define SRC_METADATA_H_
+
+#include "nan.h"
+
+NAN_METHOD(metadata);
+
+#endif  // SRC_METADATA_H_

src/operations.cc

@@ -0,0 +1,333 @@
+#include <vips/vips.h>
+
+#include "common.h"
+#include "operations.h"
+
+namespace sharp {
+
+  /*
+    Alpha composite src over dst
+    Assumes alpha channels are already premultiplied and will be unpremultiplied after
+   */
+  int Composite(VipsObject *context, VipsImage *src, VipsImage *dst, VipsImage **out) {
+    using sharp::HasAlpha;
+
+    // Split src into non-alpha and alpha
+    VipsImage *srcWithoutAlpha;
+    if (vips_extract_band(src, &srcWithoutAlpha, 0, "n", src->Bands - 1, NULL))
+      return -1;
+    vips_object_local(context, srcWithoutAlpha);
+    VipsImage *srcAlpha;
+    if (vips_extract_band(src, &srcAlpha, src->Bands - 1, "n", 1, NULL))
+      return -1;
+    vips_object_local(context, srcAlpha);
+
+    // Split dst into non-alpha and alpha channels
+    VipsImage *dstWithoutAlpha;
+    VipsImage *dstAlpha;
+    if (HasAlpha(dst)) {
+      // Non-alpha: extract all-but-last channel
+      if (vips_extract_band(dst, &dstWithoutAlpha, 0, "n", dst->Bands - 1, NULL)) {
+        return -1;
+      }
+      vips_object_local(context, dstWithoutAlpha);
+      // Alpha: Extract last channel
+      if (vips_extract_band(dst, &dstAlpha, dst->Bands - 1, "n", 1, NULL)) {
+        return -1;
+      }
+      vips_object_local(context, dstAlpha);
+    } else {
+      // Non-alpha: Copy reference
+      dstWithoutAlpha = dst;
+      // Alpha: Use blank, opaque (0xFF) image
+      VipsImage *black;
+      if (vips_black(&black, dst->Xsize, dst->Ysize, NULL)) {
+        return -1;
+      }
+      vips_object_local(context, black);
+      if (vips_invert(black, &dstAlpha, NULL)) {
+        return -1;
+      }
+      vips_object_local(context, dstAlpha);
+    }
+
+    // Compute normalized input alpha channels:
+    VipsImage *srcAlphaNormalized;
+    if (vips_linear1(srcAlpha, &srcAlphaNormalized, 1.0 / 255.0, 0.0, NULL))
+      return -1;
+    vips_object_local(context, srcAlphaNormalized);
+
+    VipsImage *dstAlphaNormalized;
+    if (vips_linear1(dstAlpha, &dstAlphaNormalized, 1.0 / 255.0, 0.0, NULL))
+      return -1;
+    vips_object_local(context, dstAlphaNormalized);
+
+    //
+    // Compute normalized output alpha channel:
+    //
+    // References:
+    // - http://en.wikipedia.org/wiki/Alpha_compositing#Alpha_blending
+    // - https://github.com/jcupitt/ruby-vips/issues/28#issuecomment-9014826
+    //
+    // out_a = src_a + dst_a * (1 - src_a)
+    //                         ^^^^^^^^^^^
+    //                            t0
+    //                 ^^^^^^^^^^^^^^^^^^^
+    //                         t1
+    VipsImage *t0;
+    if (vips_linear1(srcAlphaNormalized, &t0, -1.0, 1.0, NULL))
+      return -1;
+    vips_object_local(context, t0);
+
+    VipsImage *t1;
+    if (vips_multiply(dstAlphaNormalized, t0, &t1, NULL))
+      return -1;
+    vips_object_local(context, t1);
+
+    VipsImage *outAlphaNormalized;
+    if (vips_add(srcAlphaNormalized, t1, &outAlphaNormalized, NULL))
+      return -1;
+    vips_object_local(context, outAlphaNormalized);
+
+    //
+    // Compute output RGB channels:
+    //
+    // Wikipedia:
+    // out_rgb = (src_rgb * src_a + dst_rgb * dst_a * (1 - src_a)) / out_a
+    //                                                ^^^^^^^^^^^
+    //                                                    t0
+    //
+    // Omit division by `out_a` since `Compose` is supposed to output a
+    // premultiplied RGBA image as reversal of premultiplication is handled
+    // externally.
+    //
+    VipsImage *t2;
+    if (vips_multiply(dstWithoutAlpha, t0, &t2, NULL))
+      return -1;
+    vips_object_local(context, t2);
+
+    VipsImage *outRGBPremultiplied;
+    if (vips_add(srcWithoutAlpha, t2, &outRGBPremultiplied, NULL))
+      return -1;
+    vips_object_local(context, outRGBPremultiplied);
+
+    // Denormalize output alpha channel:
+    VipsImage *outAlpha;
+    if (vips_linear1(outAlphaNormalized, &outAlpha, 255.0, 0.0, NULL))
+      return -1;
+    vips_object_local(context, outAlpha);
+
+    // Combine RGB and alpha channel into output image:
+    return vips_bandjoin2(outRGBPremultiplied, outAlpha, out, NULL);
+  }
+
+  /*
+   * Premultiply alpha channel of `image`.
+   */
+  int Premultiply(VipsObject *context, VipsImage *image, VipsImage **out) {
+#if (VIPS_MAJOR_VERSION >= 9 || (VIPS_MAJOR_VERSION >= 8 && VIPS_MINOR_VERSION >= 1))
+    return vips_premultiply(image, out, NULL);
+#else
+    VipsImage *imageRGB;
+    if (vips_extract_band(image, &imageRGB, 0, "n", image->Bands - 1, NULL))
+      return -1;
+    vips_object_local(context, imageRGB);
+
+    VipsImage *imageAlpha;
+    if (vips_extract_band(image, &imageAlpha, image->Bands - 1, "n", 1, NULL))
+      return -1;
+    vips_object_local(context, imageAlpha);
+
+    VipsImage *imageAlphaNormalized;
+    if (vips_linear1(imageAlpha, &imageAlphaNormalized, 1.0 / 255.0, 0.0, NULL))
+      return -1;
+    vips_object_local(context, imageAlphaNormalized);
+
+    VipsImage *imageRGBPremultiplied;
+    if (vips_multiply(imageRGB, imageAlphaNormalized, &imageRGBPremultiplied, NULL))
+      return -1;
+    vips_object_local(context, imageRGBPremultiplied);
+
+    return vips_bandjoin2(imageRGBPremultiplied, imageAlpha, out, NULL);
+#endif
+  }
+
+  /*
+   * Unpremultiply alpha channel of `image`.
+   */
+  int Unpremultiply(VipsObject *context, VipsImage *image, VipsImage **out) {
+#if (VIPS_MAJOR_VERSION >= 9 || (VIPS_MAJOR_VERSION >= 8 && VIPS_MINOR_VERSION >= 1))
+    return vips_unpremultiply(image, out, NULL);
+#else
+    VipsImage *imageRGBPremultipliedTransformed;
+    if (vips_extract_band(image, &imageRGBPremultipliedTransformed, 0, "n", image->Bands - 1, NULL))
+      return -1;
+    vips_object_local(context, imageRGBPremultipliedTransformed);
+
+    VipsImage *imageAlphaTransformed;
+    if (vips_extract_band(image, &imageAlphaTransformed, image->Bands - 1, "n", 1, NULL))
+      return -1;
+    vips_object_local(context, imageAlphaTransformed);
+
+    VipsImage *imageAlphaNormalizedTransformed;
+    if (vips_linear1(imageAlphaTransformed, &imageAlphaNormalizedTransformed, 1.0 / 255.0, 0.0, NULL))
+      return -1;
+    vips_object_local(context, imageAlphaNormalizedTransformed);
+
+    VipsImage *imageRGBUnpremultipliedTransformed;
+    if (vips_divide(imageRGBPremultipliedTransformed, imageAlphaNormalizedTransformed, &imageRGBUnpremultipliedTransformed, NULL))
+      return -1;
+    vips_object_local(context, imageRGBUnpremultipliedTransformed);
+
+    return vips_bandjoin2(imageRGBUnpremultipliedTransformed, imageAlphaTransformed, out, NULL);
+#endif
+  }
+
+  /*
+   * Stretch luminance to cover full dynamic range.
+   */
+  int Normalize(VipsObject *context, VipsImage *image, VipsImage **out) {
+#ifndef _WIN32
+    // Get original colourspace
+    VipsInterpretation typeBeforeNormalize = image->Type;
+    if (typeBeforeNormalize == VIPS_INTERPRETATION_RGB) {
+      typeBeforeNormalize = VIPS_INTERPRETATION_sRGB;
+    }
+    // Convert to LAB colourspace
+    VipsImage *lab;
+    if (vips_colourspace(image, &lab, VIPS_INTERPRETATION_LAB, NULL)) {
+      return -1;
+    }
+    vips_object_local(context, lab);
+    // Extract luminance
+    VipsImage *luminance;
+    if (vips_extract_band(lab, &luminance, 0, "n", 1, NULL)) {
+      return -1;
+    }
+    vips_object_local(context, luminance);
+    // Extract chroma
+    VipsImage *chroma;
+    if (vips_extract_band(lab, &chroma, 1, "n", 2, NULL)) {
+      return -1;
+    }
+    vips_object_local(context, chroma);
+    // Find luminance range
+    VipsImage *stats;
+    if (vips_stats(luminance, &stats, NULL)) {
+      return -1;
+    }
+    vips_object_local(context, stats);
+    double min = *VIPS_MATRIX(stats, 0, 0);
+    double max = *VIPS_MATRIX(stats, 1, 0);
+    if (min != max) {
+      double f = 100.0 / (max - min);
+      double a = -(min * f);
+      // Scale luminance
+      VipsImage *luminance100;
+      if (vips_linear1(luminance, &luminance100, f, a, NULL)) {
+        return -1;
+      }
+      vips_object_local(context, luminance100);
+      // Join scaled luminance to chroma
+      VipsImage *normalizedLab;
+      if (vips_bandjoin2(luminance100, chroma, &normalizedLab, NULL)) {
+        return -1;
+      }
+      vips_object_local(context, normalizedLab);
+      // Convert to original colourspace
+      VipsImage *normalized;
+      if (vips_colourspace(normalizedLab, &normalized, typeBeforeNormalize, NULL)) {
+        return -1;
+      }
+      vips_object_local(context, normalized);
+      // Attach original alpha channel, if any
+      if (HasAlpha(image)) {
+        // Extract original alpha channel
+        VipsImage *alpha;
+        if (vips_extract_band(image, &alpha, image->Bands - 1, "n", 1, NULL)) {
+          return -1;
+        }
+        vips_object_local(context, alpha);
+        // Join alpha channel to normalised image
+        VipsImage *normalizedAlpha;
+        if (vips_bandjoin2(normalized, alpha, &normalizedAlpha, NULL)) {
+          return -1;
+        }
+        vips_object_local(context, normalizedAlpha);
+        *out = normalizedAlpha;
+      } else {
+        *out = normalized;
+      }
+    } else {
+      // Cannot normalise zero-range image
+      *out = image;
+    }
+#else
+    // The normalize operation is currently unsupported on Windows
+    // See https://github.com/lovell/sharp/issues/152
+    *out = image;
+#endif
+    return 0;
+  }
+
+  /*
+   * Gaussian blur (use sigma <0 for fast blur)
+   */
+  int Blur(VipsObject *context, VipsImage *image, VipsImage **out, double sigma) {
+    VipsImage *blurred;
+    if (sigma < 0.0) {
+      // Fast, mild blur - averages neighbouring pixels
+      VipsImage *blur = vips_image_new_matrixv(3, 3,
+        1.0, 1.0, 1.0,
+        1.0, 1.0, 1.0,
+        1.0, 1.0, 1.0);
+      vips_image_set_double(blur, "scale", 9);
+      vips_object_local(context, blur);
+      if (vips_conv(image, &blurred, blur, NULL)) {
+        return -1;
+      }
+    } else {
+      // Slower, accurate Gaussian blur
+      // Create Gaussian function for standard deviation
+      VipsImage *gaussian;
+      if (vips_gaussmat(&gaussian, sigma, 0.2, "separable", TRUE, "integer", TRUE, NULL)) {
+        return -1;
+      }
+      vips_object_local(context, gaussian);
+      // Apply Gaussian function
+      if (vips_convsep(image, &blurred, gaussian, "precision", VIPS_PRECISION_INTEGER, NULL)) {
+        return -1;
+      }
+    }
+    vips_object_local(context, blurred);
+    *out = blurred;
+    return 0;
+  }
+
+  /*
+   * Sharpen flat and jagged areas. Use radius of -1 for fast sharpen.
+   */
+  int Sharpen(VipsObject *context, VipsImage *image, VipsImage **out, int radius, double flat, double jagged) {
+    VipsImage *sharpened;
+    if (radius == -1) {
+      // Fast, mild 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);
+      vips_object_local(context, sharpen);
+      if (vips_conv(image, &sharpened, sharpen, NULL)) {
+        return -1;
+      }
+    } else {
+      // Slow, accurate sharpen in LAB colour space, with control over flat vs jagged areas
+      if (vips_sharpen(image, &sharpened, "radius", radius, "m1", flat, "m2", jagged, NULL)) {
+        return -1;
+      }
+    }
+    vips_object_local(context, sharpened);
+    *out = sharpened;
+    return 0;
+  }
+}  // namespace sharp

src/operations.h

@@ -0,0 +1,39 @@
+#ifndef SRC_OPERATIONS_H_
+#define SRC_OPERATIONS_H_
+
+namespace sharp {
+
+  /*
+    Composite images `src` and `dst` with premultiplied alpha channel and output
+    image with premultiplied alpha.
+   */
+  int Composite(VipsObject *context, VipsImage *src, VipsImage *dst, VipsImage **out);
+
+  /*
+   * Premultiply alpha channel of `image`.
+   */
+  int Premultiply(VipsObject *context, VipsImage *image, VipsImage **out);
+
+  /*
+   * Unpremultiply alpha channel of `image`.
+   */
+  int Unpremultiply(VipsObject *context, VipsImage *image, VipsImage **out);
+
+  /*
+   * Stretch luminance to cover full dynamic range.
+   */
+  int Normalize(VipsObject *context, VipsImage *image, VipsImage **out);
+
+  /*
+   * Gaussian blur. Use sigma of -1 for fast blur.
+   */
+  int Blur(VipsObject *context, VipsImage *image, VipsImage **out, double sigma);
+
+  /*
+   * Sharpen flat and jagged areas. Use radius of -1 for fast sharpen.
+   */
+  int Sharpen(VipsObject *context, VipsImage *image, VipsImage **out, int radius, double flat, double jagged);
+
+}  // namespace sharp
+
+#endif  // SRC_OPERATIONS_H_

src/pipeline.h

@@ -0,0 +1,8 @@
+#ifndef SRC_PIPELINE_H_
+#define SRC_PIPELINE_H_
+
+#include "nan.h"
+
+NAN_METHOD(pipeline);
+
+#endif  // SRC_PIPELINE_H_

src/sharp.cc

@@ -1,227 +1,37 @@
 #include <node.h>
-#include <math.h>
-#include <string>
-#include <vector>
 #include <vips/vips.h>
-#include <node_buffer.h>
 
-using namespace v8;
-using namespace node;
+#include "nan.h"
 
-// Free VipsImage children when object goes out of scope
-// Thanks due to https://github.com/dosx/node-vips
-class ImageFreer {
-  public:
-    ImageFreer() {}
-    ~ImageFreer() {
-      for (uint16_t i = 0; i < v_.size(); i++) {
-        if (v_[i] != NULL) {
-          g_object_unref(v_[i]);
-        }
-      }
-      v_.clear();
-    }
-    void add(VipsImage* i) { v_.push_back(i); }
-  private:
-    std::vector<VipsImage*> v_;
-};
+#include "common.h"
+#include "metadata.h"
+#include "pipeline.h"
+#include "utilities.h"
 
-struct ResizeBaton {
-  std::string src;
-  std::string dst;
-  void* buffer_out;
-  size_t buffer_out_len;
-  int  cols;
-  int  rows;
-  bool crop;
-  int  embed;
-  std::string err;
-  Persistent<Function> callback;
+NAN_MODULE_INIT(init) {
+  vips_init("sharp");
 
-  ResizeBaton() : buffer_out_len(0) {}
-};
+  // Set libvips operation cache limits
+  vips_cache_set_max_mem(100 * 1024 * 1024); // 100 MB
+  vips_cache_set_max(500); // 500 operations
 
-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);
+  // Methods available to JavaScript
+  Nan::Set(target, Nan::New("metadata").ToLocalChecked(),
+    Nan::GetFunction(Nan::New<v8::FunctionTemplate>(metadata)).ToLocalChecked());
+  Nan::Set(target, Nan::New("pipeline").ToLocalChecked(),
+    Nan::GetFunction(Nan::New<v8::FunctionTemplate>(pipeline)).ToLocalChecked());
+  Nan::Set(target, Nan::New("cache").ToLocalChecked(),
+    Nan::GetFunction(Nan::New<v8::FunctionTemplate>(cache)).ToLocalChecked());
+  Nan::Set(target, Nan::New("concurrency").ToLocalChecked(),
+    Nan::GetFunction(Nan::New<v8::FunctionTemplate>(concurrency)).ToLocalChecked());
+  Nan::Set(target, Nan::New("counters").ToLocalChecked(),
+    Nan::GetFunction(Nan::New<v8::FunctionTemplate>(counters)).ToLocalChecked());
+  Nan::Set(target, Nan::New("libvipsVersion").ToLocalChecked(),
+    Nan::GetFunction(Nan::New<v8::FunctionTemplate>(libvipsVersion)).ToLocalChecked());
+  Nan::Set(target, Nan::New("format").ToLocalChecked(),
+    Nan::GetFunction(Nan::New<v8::FunctionTemplate>(format)).ToLocalChecked());
+  Nan::Set(target, Nan::New("_maxColourDistance").ToLocalChecked(),
+    Nan::GetFunction(Nan::New<v8::FunctionTemplate>(_maxColourDistance)).ToLocalChecked());
 }
 
-void ResizeAsync(uv_work_t *work) {
-  ResizeBaton* baton = static_cast<ResizeBaton*>(work->data);
-
-  VipsImage *in = vips_image_new_mode((baton->src).c_str(), "p");
-  if (EndsWith(baton->src, ".jpg") || EndsWith(baton->src, ".jpeg"))  {
-    vips_jpegload((baton->src).c_str(), &in, NULL);
-  } else if (EndsWith(baton->src, ".png")) {
-    vips_pngload((baton->src).c_str(), &in, NULL);
-  } else {
-    (baton->err).append("Unsupported input file type");
-    return;
-  }
-  if (in == NULL) {
-    (baton->err).append(vips_error_buffer());
-    vips_error_clear();
-    return;
-  }
-  ImageFreer freer;
-  freer.add(in);
-
-  VipsImage* img = in;
-  VipsImage* t[4];
-
-  if (im_open_local_array(img, t, 4, "temp", "p")) {
-    (baton->err).append(vips_error_buffer());
-    vips_error_clear();
-    return;
-  }
-
-  double xfactor = static_cast<double>(img->Xsize) / std::max(baton->cols, 1);
-  double yfactor = static_cast<double>(img->Ysize) / std::max(baton->rows, 1);
-  double factor = baton->crop ? std::min(xfactor, yfactor) : std::max(xfactor, yfactor);
-  factor = std::max(factor, 1.0);
-  int shrink = floor(factor);
-  double residual = shrink / factor;
-
-  // Use im_shrink with the integral reduction
-  if (im_shrink(img, t[0], shrink, shrink)) {
-    (baton->err).append(vips_error_buffer());
-    vips_error_clear();
-    return;
-  }
-
-  // Use im_affinei with the remaining float part using bilinear interpolation
-  if (im_affinei_all(t[0], t[1], vips_interpolate_bilinear_static(), residual, 0, 0, residual, 0, 0)) {
-    (baton->err).append(vips_error_buffer());
-    vips_error_clear();
-    return;
-  }
-  img = t[1];
-
-  if (baton->crop) {
-    int width = std::min(img->Xsize, baton->cols);
-    int height = std::min(img->Ysize, baton->rows);
-    int left = (img->Xsize - width + 1) / 2;
-    int top = (img->Ysize - height + 1) / 2;
-    if (im_extract_area(img, t[2], left, top, width, height)) {
-      (baton->err).append(vips_error_buffer());
-      vips_error_clear();
-      return;
-    }
-    img = t[2];
-  } else {
-    int left = (baton->cols - img->Xsize) / 2;
-    int top = (baton->rows - img->Ysize) / 2;
-    if (im_embed(img, t[2], baton->embed, left, top, baton->cols, baton->rows)) {
-      (baton->err).append(vips_error_buffer());
-      vips_error_clear();
-      return;
-    }
-    img = t[2];
-  }
-
-  // Mild sharpen
-  INTMASK* sharpen = im_create_imaskv("sharpen", 3, 3,
-    -1, -1, -1,
-    -1, 32, -1,
-    -1, -1, -1);
-  sharpen->scale = 24;
-  if (im_conv(img, t[3], sharpen)) { 
-    (baton->err).append(vips_error_buffer());
-    vips_error_clear();
-    return;
-  }
-  img = t[3];
-
-  if (baton->dst == "__jpeg") {
-    // Write JPEG to buffer
-    if (vips_jpegsave_buffer(img, &baton->buffer_out, &baton->buffer_out_len, "strip", TRUE, "Q", 80, "optimize_coding", TRUE, NULL)) {
-      (baton->err).append(vips_error_buffer());
-      vips_error_clear();
-      return;
-    }
-  } else if (baton->dst == "__png") {
-    // Write PNG to buffer
-    if (vips_pngsave_buffer(img, &baton->buffer_out, &baton->buffer_out_len, "strip", TRUE, "compression", 6, "interlace", FALSE, NULL)) {
-      (baton->err).append(vips_error_buffer());
-      vips_error_clear();
-      return;
-    }
-  } else if (EndsWith(baton->dst, ".jpg") || EndsWith(baton->dst, ".jpeg"))  {
-    // Write JPEG to file
-    if (vips_foreign_save(img, baton->dst.c_str(), "strip", TRUE, "Q", 80, "optimize_coding", TRUE, NULL)) {
-      (baton->err).append(vips_error_buffer());
-      vips_error_clear();
-    }
-  } else if (EndsWith(baton->dst, ".png")) {
-    // Write PNG to file
-    if (vips_foreign_save(img, baton->dst.c_str(), "strip", TRUE, "compression", 6, "interlace", FALSE, NULL)) {
-      (baton->err).append(vips_error_buffer());
-      vips_error_clear();
-    }
-  } else {
-    (baton->err).append("Unsupported output file type");
-  }
-  vips_thread_shutdown();
-}
-
-void ResizeAsyncAfter(uv_work_t *work, int status) {
-  HandleScope scope;
-
-  ResizeBaton *baton = static_cast<ResizeBaton*>(work->data);
-
-  Local<Value> null = Local<Value>::New(Null());
-  Local<Value> argv[2] = {null, null};
-  if (!baton->err.empty()) {
-    // Error
-    argv[0] = String::New(baton->err.data(), baton->err.size());
-  } else if (baton->buffer_out_len > 0) {
-    // Buffer
-    Buffer *buffer = Buffer::New((const char*)(baton->buffer_out), baton->buffer_out_len);
-    argv[1] = Local<Object>::New(buffer->handle_);
-    vips_free(baton->buffer_out);
-  }
-
-  baton->callback->Call(Context::GetCurrent()->Global(), 2, argv);
-  baton->callback.Dispose();
-  delete baton;
-  delete work;
-}
-
-Handle<Value> Resize(const Arguments& args) {
-  HandleScope scope;
-  
-  ResizeBaton *baton = new ResizeBaton;
-  baton->src = *String::Utf8Value(args[0]->ToString());
-  baton->dst = *String::Utf8Value(args[1]->ToString());
-  baton->cols = args[2]->Int32Value();
-  baton->rows = args[3]->Int32Value();
-  Local<String> canvas = args[4]->ToString();
-  if (canvas->Equals(String::NewSymbol("c"))) {
-    baton->crop = true;
-  } else if (canvas->Equals(String::NewSymbol("w"))) {
-    baton->crop = false;
-    baton->embed = 4;
-  } else if (canvas->Equals(String::NewSymbol("b"))) {
-    baton->crop = false;
-    baton->embed = 0;
-  }
-  baton->callback = Persistent<Function>::New(Local<Function>::Cast(args[5]));
-
-  uv_work_t *work = new uv_work_t;
-  work->data = baton;
-  uv_queue_work(uv_default_loop(), work, ResizeAsync, (uv_after_work_cb)ResizeAsyncAfter);
-  return Undefined();
-}
-
-static void at_exit(void* arg) {
-  HandleScope scope;
-  vips_shutdown();
-}
-
-extern "C" void init(Handle<Object> target) {
-  HandleScope scope;
-  vips_init("");
-  AtExit(at_exit);
-  NODE_SET_METHOD(target, "resize", Resize);
-};
-
-NODE_MODULE(sharp, init);
+NODE_MODULE(sharp, init)

src/utilities.cc

@@ -0,0 +1,258 @@
+#include <node.h>
+#include <vips/vips.h>
+
+#include "nan.h"
+
+#include "common.h"
+#include "operations.h"
+#include "utilities.h"
+
+using v8::Local;
+using v8::Object;
+using v8::Number;
+using v8::String;
+using v8::Boolean;
+
+using Nan::HandleScope;
+using Nan::New;
+using Nan::Set;
+using Nan::ThrowError;
+using Nan::To;
+using Nan::Utf8String;
+
+/*
+  Get and set cache memory and item limits
+*/
+NAN_METHOD(cache) {
+  HandleScope();
+
+  // Set cache memory limit
+  if (info[0]->IsInt32()) {
+    vips_cache_set_max_mem(To<int32_t>(info[0]).FromJust() * 1048576);
+  }
+
+  // Set cache items limit
+  if (info[1]->IsInt32()) {
+    vips_cache_set_max(To<int32_t>(info[1]).FromJust());
+  }
+
+  // Get cache statistics
+  Local<Object> cache = New<Object>();
+  Set(cache, New("current").ToLocalChecked(), New<Number>(vips_tracked_get_mem() / 1048576));
+  Set(cache, New("high").ToLocalChecked(), New<Number>(vips_tracked_get_mem_highwater() / 1048576));
+  Set(cache, New("memory").ToLocalChecked(), New<Number>(vips_cache_get_max_mem() / 1048576));
+  Set(cache, New("items").ToLocalChecked(), New<Number>(vips_cache_get_max()));
+  info.GetReturnValue().Set(cache);
+}
+
+/*
+  Get and set size of thread pool
+*/
+NAN_METHOD(concurrency) {
+  HandleScope();
+
+  // Set concurrency
+  if (info[0]->IsInt32()) {
+    vips_concurrency_set(To<int32_t>(info[0]).FromJust());
+  }
+  // Get concurrency
+  info.GetReturnValue().Set(New<Number>(vips_concurrency_get()));
+}
+
+/*
+  Get internal counters (queued tasks, processing tasks)
+*/
+NAN_METHOD(counters) {
+  using sharp::counterProcess;
+  using sharp::counterQueue;
+
+  HandleScope();
+  Local<Object> counters = New<Object>();
+  Set(counters, New("queue").ToLocalChecked(), New<Number>(counterQueue));
+  Set(counters, New("process").ToLocalChecked(), New<Number>(counterProcess));
+  info.GetReturnValue().Set(counters);
+}
+
+/*
+  Get libvips version
+*/
+NAN_METHOD(libvipsVersion) {
+  HandleScope();
+  char version[9];
+  g_snprintf(version, sizeof(version), "%d.%d.%d", vips_version(0), vips_version(1), vips_version(2));
+  info.GetReturnValue().Set(New(version).ToLocalChecked());
+}
+
+/*
+  Get available input/output file/buffer/stream formats
+*/
+NAN_METHOD(format) {
+  HandleScope();
+
+  // Attribute names
+  Local<String> attrId = New("id").ToLocalChecked();
+  Local<String> attrInput = New("input").ToLocalChecked();
+  Local<String> attrOutput = New("output").ToLocalChecked();
+  Local<String> attrFile = New("file").ToLocalChecked();
+  Local<String> attrBuffer = New("buffer").ToLocalChecked();
+  Local<String> attrStream = New("stream").ToLocalChecked();
+
+  // Which load/save operations are available for each compressed format?
+  Local<Object> format = New<Object>();
+  for (std::string f : {"jpeg", "png", "webp", "tiff", "magick", "openslide", "dz"}) {
+    // Input
+    Local<Boolean> hasInputFile =
+      New<Boolean>(vips_type_find("VipsOperation", (f + "load").c_str()));
+    Local<Boolean> hasInputBuffer =
+      New<Boolean>(vips_type_find("VipsOperation", (f + "load_buffer").c_str()));
+    Local<Object> input = New<Object>();
+    Set(input, attrFile, hasInputFile);
+    Set(input, attrBuffer, hasInputBuffer);
+    Set(input, attrStream, hasInputBuffer);
+    // Output
+    Local<Boolean> hasOutputFile =
+      New<Boolean>(vips_type_find("VipsOperation", (f + "save").c_str()));
+    Local<Boolean> hasOutputBuffer =
+      New<Boolean>(vips_type_find("VipsOperation", (f + "save_buffer").c_str()));
+    Local<Object> output = New<Object>();
+    Set(output, attrFile, hasOutputFile);
+    Set(output, attrBuffer, hasOutputBuffer);
+    Set(output, attrStream, hasOutputBuffer);
+    // Other attributes
+    Local<Object> container = New<Object>();
+    Local<String> formatId = New(f).ToLocalChecked();
+    Set(container, attrId, formatId);
+    Set(container, attrInput, input);
+    Set(container, attrOutput, output);
+    // Add to set of formats
+    Set(format, formatId, container);
+  }
+
+  // Raw, uncompressed data
+  Local<Object> raw = New<Object>();
+  Local<String> rawId = New("raw").ToLocalChecked();
+  Set(raw, attrId, rawId);
+  Set(format, rawId, raw);
+  // No support for raw input yet, so always false
+  Local<Boolean> unsupported = New<Boolean>(false);
+  Local<Object> rawInput = New<Object>();
+  Set(rawInput, attrFile, unsupported);
+  Set(rawInput, attrBuffer, unsupported);
+  Set(rawInput, attrStream, unsupported);
+  Set(raw, attrInput, rawInput);
+  // Raw output via Buffer/Stream is available in libvips >= 7.42.0
+  Local<Boolean> hasOutputBufferRaw = New<Boolean>(vips_version(0) >= 8 || (vips_version(0) == 7 && vips_version(1) >= 42));
+  Local<Object> rawOutput = New<Object>();
+  Set(rawOutput, attrFile, unsupported);
+  Set(rawOutput, attrBuffer, hasOutputBufferRaw);
+  Set(rawOutput, attrStream, hasOutputBufferRaw);
+  Set(raw, attrOutput, rawOutput);
+
+  info.GetReturnValue().Set(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.
+*/
+NAN_METHOD(_maxColourDistance) {
+  using sharp::Premultiply;
+  using sharp::DetermineImageType;
+  using sharp::ImageType;
+  using sharp::InitImage;
+  using sharp::HasAlpha;
+
+  HandleScope();
+
+  // Create "hook" VipsObject to hang image references from
+  VipsObject *hook = reinterpret_cast<VipsObject*>(vips_image_new());
+
+  // Open input files
+  VipsImage *image1 = NULL;
+  ImageType imageType1 = DetermineImageType(*Utf8String(info[0]));
+  if (imageType1 != ImageType::UNKNOWN) {
+    image1 = InitImage(*Utf8String(info[0]), VIPS_ACCESS_SEQUENTIAL);
+    if (image1 == NULL) {
+      g_object_unref(hook);
+      return ThrowError("Input file 1 has corrupt header");
+    } else {
+      vips_object_local(hook, image1);
+    }
+  } else {
+    g_object_unref(hook);
+    return ThrowError("Input file 1 is of an unsupported image format");
+  }
+  VipsImage *image2 = NULL;
+  ImageType imageType2 = DetermineImageType(*Utf8String(info[1]));
+  if (imageType2 != ImageType::UNKNOWN) {
+    image2 = InitImage(*Utf8String(info[1]), VIPS_ACCESS_SEQUENTIAL);
+    if (image2 == NULL) {
+      g_object_unref(hook);
+      return ThrowError("Input file 2 has corrupt header");
+    } else {
+      vips_object_local(hook, image2);
+    }
+  } else {
+    g_object_unref(hook);
+    return ThrowError("Input file 2 is of an unsupported image format");
+  }
+
+  // Ensure same number of channels
+  if (image1->Bands != image2->Bands) {
+    g_object_unref(hook);
+    return ThrowError("mismatchedBands");
+  }
+  // Ensure same dimensions
+  if (image1->Xsize != image2->Xsize || image1->Ysize != image2->Ysize) {
+    g_object_unref(hook);
+    return ThrowError("mismatchedDimensions");
+  }
+
+  // Premultiply and remove alpha
+  if (HasAlpha(image1)) {
+    VipsImage *imagePremultiplied1;
+    if (Premultiply(hook, image1, &imagePremultiplied1)) {
+      g_object_unref(hook);
+      return ThrowError(vips_error_buffer());
+    }
+    vips_object_local(hook, imagePremultiplied1);
+    VipsImage *imagePremultipliedNoAlpha1;
+    if (vips_extract_band(image1, &imagePremultipliedNoAlpha1, 1, "n", image1->Bands - 1, NULL)) {
+      g_object_unref(hook);
+      return ThrowError(vips_error_buffer());
+    }
+    vips_object_local(hook, imagePremultipliedNoAlpha1);
+    image1 = imagePremultipliedNoAlpha1;
+  }
+  if (HasAlpha(image2)) {
+    VipsImage *imagePremultiplied2;
+    if (Premultiply(hook, image2, &imagePremultiplied2)) {
+      g_object_unref(hook);
+      return ThrowError(vips_error_buffer());
+    }
+    vips_object_local(hook, imagePremultiplied2);
+    VipsImage *imagePremultipliedNoAlpha2;
+    if (vips_extract_band(image2, &imagePremultipliedNoAlpha2, 1, "n", image2->Bands - 1, NULL)) {
+      g_object_unref(hook);
+      return ThrowError(vips_error_buffer());
+    }
+    vips_object_local(hook, imagePremultipliedNoAlpha2);
+    image2 = imagePremultipliedNoAlpha2;
+  }
+  // Calculate colour distance
+  VipsImage *difference;
+  if (vips_dE00(image1, image2, &difference, NULL)) {
+    g_object_unref(hook);
+    return ThrowError(vips_error_buffer());
+  }
+  vips_object_local(hook, difference);
+  // Extract maximum distance
+  double maxColourDistance;
+  if (vips_max(difference, &maxColourDistance, NULL)) {
+    g_object_unref(hook);
+    return ThrowError(vips_error_buffer());
+  }
+  g_object_unref(hook);
+  info.GetReturnValue().Set(New<Number>(maxColourDistance));
+}

src/utilities.h

@@ -0,0 +1,13 @@
+#ifndef SRC_UTILITIES_H_
+#define SRC_UTILITIES_H_
+
+#include "nan.h"
+
+NAN_METHOD(cache);
+NAN_METHOD(concurrency);
+NAN_METHOD(counters);
+NAN_METHOD(libvipsVersion);
+NAN_METHOD(format);
+NAN_METHOD(_maxColourDistance);
+
+#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": {
+    "imagemagick": "^0.1.3",
+    "imagemagick-native": "^1.8.0",
+    "gm": "^1.18.1",
+    "lwip": "^0.0.7",
+    "async": "^1.4.2",
+    "semver": "^5.0.1",
+    "benchmark": "^1.0.0"
+  },
+  "license": "Apache-2.0",
+  "engines": {
+    "node": ">=0.10"
+  }
+}

test/bench/parallel.js

@@ -0,0 +1,41 @@
+'use strict';
+
+var assert = require('assert');
+var async = require('async');
+
+var sharp = require('../../index');
+var fixtures = require('../fixtures');
+
+var width = 720;
+var height = 480;
+
+sharp.concurrency(1);
+
+var timer = setInterval(function() {
+  console.dir(sharp.counters());
+}, 100);
+
+async.mapSeries([1, 1, 2, 4, 8, 16, 32, 64, 128], function(parallelism, next) {
+  var 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);
+      var 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 +1,708 @@
+'use strict';
+
+var fs = require('fs');
+
+var async = require('async');
+var assert = require('assert');
+var Benchmark = require('benchmark');
+var semver = require('semver');
+
+// Contenders
+var gm = require('gm');
+var imagemagick = require('imagemagick');
+var sharp = require('../../index');
+var imagemagickNative;
+try {
+  imagemagickNative = require('imagemagick-native');
+} catch (err) {
+  console.log('Excluding imagemagick-native');
+}
+var lwip;
+try {
+  lwip = require('lwip');
+} catch (err) {
+  console.log('Excluding lwip');
+}
+
+var fixtures = require('../fixtures');
+
+var width = 720;
+var height = 480;
+
+// Approximately equivalent to fast bilinear
+var magickFilter = 'Triangle';
+
+// Disable libvips cache to ensure tests are as fair as they can be
+sharp.cache(0);
+
+async.series({
+  jpeg: function(callback) {
+    var inputJpgBuffer = fs.readFileSync(fixtures.inputJpg);
+    var jpegSuite = new Benchmark.Suite('jpeg');
+    // lwip
+    if (typeof lwip !== 'undefined') {
+      jpegSuite.add('lwip-file-file', {
+        defer: true,
+        fn: function(deferred) {
+          lwip.open(fixtures.inputJpg, function (err, image) {
+            if (err) {
+              throw err;
+            }
+            image.resize(width, height, 'linear', function (err, image) {
+              if (err) {
+                throw err;
+              }
+              image.writeFile(fixtures.outputJpg, {quality: 80}, function (err) {
+                if (err) {
+                  throw err;
+                }
+                deferred.resolve();
+              });
+            });
+          });
+        }
+      }).add('lwip-buffer-buffer', {
+        defer: true,
+        fn: function(deferred) {
+          lwip.open(inputJpgBuffer, 'jpg', function (err, image) {
+            if (err) {
+              throw err;
+            }
+            image.resize(width, height, 'linear', function (err, image) {
+              if (err) {
+                throw err;
+              }
+              image.toBuffer('jpg', {quality: 80}, function (err, buffer) {
+                if (err) {
+                  throw err;
+                }
+                assert.notStrictEqual(null, buffer);
+                deferred.resolve();
+              });
+            });
+          });
+        }
+      });
+    }
+    // imagemagick
+    jpegSuite.add('imagemagick-file-file', {
+      defer: true,
+      fn: function(deferred) {
+        imagemagick.resize({
+          srcPath: fixtures.inputJpg,
+          dstPath: fixtures.outputJpg,
+          quality: 0.8,
+          width: width,
+          height: height,
+          format: 'jpg',
+          filter: magickFilter
+        }, function(err) {
+          if (err) {
+            throw err;
+          } else {
+            deferred.resolve();
+          }
+        });
+      }
+    });
+    // imagemagick-native
+    if (typeof imagemagickNative !== 'undefined') {
+      jpegSuite.add('imagemagick-native-buffer-buffer', {
+        defer: true,
+        fn: function(deferred) {
+          imagemagickNative.convert({
+            srcData: inputJpgBuffer,
+            quality: 80,
+            width: width,
+            height: height,
+            format: 'JPEG',
+            filter: magickFilter
+          }, function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+        }
+      });
+    }
+    // gm
+    jpegSuite.add('gm-buffer-file', {
+      defer: true,
+      fn: function(deferred) {
+        gm(inputJpgBuffer)
+          .resize(width, height)
+          .filter(magickFilter)
+          .quality(80)
+          .write(fixtures.outputJpg, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('gm-buffer-buffer', {
+      defer: true,
+      fn: function(deferred) {
+        gm(inputJpgBuffer)
+          .resize(width, height)
+          .filter(magickFilter)
+          .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)
+          .resize(width, height)
+          .filter(magickFilter)
+          .quality(80)
+          .write(fixtures.outputJpg, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('gm-file-buffer', {
+      defer: true,
+      fn: function(deferred) {
+        gm(fixtures.inputJpg)
+          .resize(width, height)
+          .filter(magickFilter)
+          .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(fixtures.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(fixtures.outputJpg, function(err) {
+          if (err) {
+            throw err;
+          } else {
+            deferred.resolve();
+          }
+        });
+      }
+    }).add('sharp-stream-stream', {
+      defer: true,
+      fn: function(deferred) {
+        var readable = fs.createReadStream(fixtures.inputJpg);
+        var writable = fs.createWriteStream(fixtures.outputJpg);
+        writable.on('finish', function() {
+          deferred.resolve();
+        });
+        var 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();
+        });
+      }
+    }).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-nearest-neighbour', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(inputJpgBuffer).resize(width, height).interpolateWith(sharp.interpolator.nearest).toBuffer(function(err, buffer) {
+          if (err) {
+            throw err;
+          } else {
+            assert.notStrictEqual(null, buffer);
+            deferred.resolve();
+          }
+        });
+      }
+    }).add('sharp-bicubic', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(inputJpgBuffer).resize(width, height).interpolateWith(sharp.interpolator.bicubic).toBuffer(function(err, buffer) {
+          if (err) {
+            throw err;
+          } else {
+            assert.notStrictEqual(null, buffer);
+            deferred.resolve();
+          }
+        });
+      }
+    }).add('sharp-nohalo', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(inputJpgBuffer).resize(width, height).interpolateWith(sharp.interpolator.nohalo).toBuffer(function(err, buffer) {
+          if (err) {
+            throw err;
+          } else {
+            assert.notStrictEqual(null, buffer);
+            deferred.resolve();
+          }
+        });
+      }
+    }).add('sharp-locallyBoundedBicubic', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(inputJpgBuffer).resize(width, height).interpolateWith(sharp.interpolator.locallyBoundedBicubic).toBuffer(function(err, buffer) {
+          if (err) {
+            throw err;
+          } else {
+            assert.notStrictEqual(null, buffer);
+            deferred.resolve();
+          }
+        });
+      }
+    }).add('sharp-vertexSplitQuadraticBasisSpline', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(inputJpgBuffer).resize(width, height).interpolateWith(sharp.interpolator.vertexSplitQuadraticBasisSpline).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).progressive().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).withoutChromaSubsampling().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-sequentialRead', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(inputJpgBuffer).resize(width, height).sequentialRead().toBuffer(function(err, buffer) {
+          if (err) {
+            throw err;
+          } else {
+            assert.notStrictEqual(null, buffer);
+            deferred.resolve();
+          }
+        });
+      }
+    }).on('cycle', function(event) {
+      console.log('jpeg ' + String(event.target));
+    }).on('complete', function() {
+      callback(null, this.filter('fastest').pluck('name'));
+    }).run();
+  },
+  png: function(callback) {
+    var inputPngBuffer = fs.readFileSync(fixtures.inputPng);
+    var pngSuite = new Benchmark.Suite('png');
+    // lwip
+    if (typeof lwip !== 'undefined') {
+      pngSuite.add('lwip-buffer-buffer', {
+        defer: true,
+        fn: function(deferred) {
+          lwip.open(inputPngBuffer, 'png', function (err, image) {
+            if (err) {
+              throw err;
+            }
+            image.resize(width, height, 'linear', function (err, image) {
+              if (err) {
+                throw err;
+              }
+              image.toBuffer('png', function (err, buffer) {
+                if (err) {
+                  throw err;
+                }
+                assert.notStrictEqual(null, buffer);
+                deferred.resolve();
+              });
+            });
+          });
+        }
+      });
+    }
+    // imagemagick
+    pngSuite.add('imagemagick-file-file', {
+      defer: true,
+      fn: function(deferred) {
+        imagemagick.resize({
+          srcPath: fixtures.inputPng,
+          dstPath: fixtures.outputPng,
+          width: width,
+          height: height,
+          filter: magickFilter
+        }, function(err) {
+          if (err) {
+            throw err;
+          } else {
+            deferred.resolve();
+          }
+        });
+      }
+    });
+    // imagemagick-native
+    if (typeof imagemagickNative !== 'undefined') {
+      pngSuite.add('imagemagick-native-buffer-buffer', {
+        defer: true,
+        fn: function(deferred) {
+          imagemagickNative.convert({
+            srcData: inputPngBuffer,
+            width: width,
+            height: height,
+            format: 'PNG',
+            filter: magickFilter
+          });
+          deferred.resolve();
+        }
+      });
+    }
+    // gm
+    pngSuite.add('gm-file-file', {
+      defer: true,
+      fn: function(deferred) {
+        gm(fixtures.inputPng)
+          .resize(width, height)
+          .filter(magickFilter)
+          .write(fixtures.outputPng, function (err) {
+            if (err) {
+              throw err;
+            } else {
+              deferred.resolve();
+            }
+          });
+      }
+    }).add('gm-file-buffer', {
+      defer: true,
+      fn: function(deferred) {
+        gm(fixtures.inputPng)
+          .resize(width, height)
+          .filter(magickFilter)
+          .toBuffer(function (err, buffer) {
+            if (err) {
+              throw err;
+            } else {
+              assert.notStrictEqual(null, buffer);
+              deferred.resolve();
+            }
+          });
+      }
+    });
+    // sharp
+    pngSuite.add('sharp-buffer-file', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(inputPngBuffer).resize(width, height).toFile(fixtures.outputPng, function(err) {
+          if (err) {
+            throw err;
+          } else {
+            deferred.resolve();
+          }
+        });
+      }
+    }).add('sharp-buffer-buffer', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(inputPngBuffer).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.inputPng).resize(width, height).toFile(fixtures.outputPng, function(err) {
+          if (err) {
+            throw err;
+          } else {
+            deferred.resolve();
+          }
+        });
+      }
+    }).add('sharp-file-buffer', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(fixtures.inputPng).resize(width, height).toBuffer(function(err, buffer) {
+          if (err) {
+            throw err;
+          } else {
+            assert.notStrictEqual(null, buffer);
+            deferred.resolve();
+          }
+        });
+      }
+    }).add('sharp-progressive', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(inputPngBuffer).resize(width, height).progressive().toBuffer(function(err, buffer) {
+          if (err) {
+            throw err;
+          } else {
+            assert.notStrictEqual(null, buffer);
+            deferred.resolve();
+          }
+        });
+      }
+    });
+    if (semver.gte(sharp.libvipsVersion(), '7.41.0')) {
+      pngSuite.add('sharp-withoutAdaptiveFiltering', {
+        defer: true,
+        fn: function(deferred) {
+          sharp(inputPngBuffer).resize(width, height).withoutAdaptiveFiltering().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').pluck('name'));
+    }).run();
+  },
+  webp: function(callback) {
+    var inputWebPBuffer = fs.readFileSync(fixtures.inputWebP);
+    (new Benchmark.Suite('webp')).add('sharp-buffer-file', {
+      defer: true,
+      fn: function(deferred) {
+        sharp(inputWebPBuffer).resize(width, height).toFile(fixtures.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(fixtures.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').pluck('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 +1,74 @@
+'use strict';
+
+var imagemagick = require('imagemagick');
+var gm = require('gm');
+var assert = require('assert');
+var Benchmark = require('benchmark');
+
+var sharp = require('../../index');
+var fixtures = require('../fixtures');
+
+var min = 320;
+var max = 960;
+
+// Nearest equivalent to bilinear
+var magickFilter = 'Triangle';
+
+var 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.outputJpg,
+      quality: 0.8,
+      width: randomDimension(),
+      height: randomDimension(),
+      format: 'jpg',
+      filter: magickFilter
+    }, function(err) {
+      if (err) {
+        throw err;
+      } else {
+        deferred.resolve();
+      }
+    });
+  }
+}).add('gm', {
+  defer: true,
+  fn: function(deferred) {
+    gm(fixtures.inputJpg)
+      .resize(randomDimension(), randomDimension())
+      .filter(magickFilter)
+      .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() {
+  var winner = this.filter('fastest').pluck('name');
+  assert.strictEqual('sharp', String(winner), 'sharp was slower than ' + winner);
+  console.dir(sharp.cache());
+}).run();

test/fixtures/Wikimedia-logo.svg

@@ -0,0 +1,17 @@
+<?xml version="1.0" standalone="yes"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1"
+   id="Wikimedia logo"
+   viewBox="-599 -599 1198 1198" width="1024" height="1024">
+<defs>
+  <clipPath id="mask">
+    <path d="M 47.5,-87.5 v 425 h -95 v -425 l -552,-552 v 1250 h 1199 v -1250 z" />
+  </clipPath>
+</defs>
+<g clip-path="url(#mask)">
+  <circle id="green parts" fill="#396" r="336.5"/>
+  <circle id="blue arc" fill="none" stroke="#069" r="480.25" stroke-width="135.5" />
+</g>
+<circle fill="#900" cy="-379.5" r="184.5" id="red circle"/>
+</svg>