Release v0.20.7

Alpha for colour is between 0-1, not 0-255.

.gitignore

@@ -12,3 +12,4 @@ vendor
 .gitattributes
 .DS_Store
 .nyc_output
+package-lock.json

.npmignore

@@ -2,13 +2,14 @@ build
 node_modules
 coverage
 .editorconfig
+.gitattributes
 .gitignore
 test
 .travis.yml
 appveyor.yml
-circle.yml
 mkdocs.yml
+docs/css/
 vendor
-packaging
-preinstall.sh
+.prebuildrc
 .nyc_output
+CONTRIBUTING.md

.prebuildrc

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

.travis.yml

@@ -16,7 +16,7 @@ matrix:
     - os: linux
       dist: trusty
       sudo: false
-      node_js: "9"
+      node_js: "10"
     - os: osx
       osx_image: xcode8.3
       node_js: "4"
@@ -28,7 +28,7 @@ matrix:
       node_js: "8"
     - os: osx
       osx_image: xcode8.3
-      node_js: "9"
+      node_js: "10"
 after_success:
   - npm install coveralls
   - cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js

CONTRIBUTING.md

@@ -41,8 +41,8 @@ Any change that modifies the existing public API should be added to the relevant
 
 | Release | WIP branch |
 | ------: | :--------- |
-| v0.19.0 | suit       |
-| v0.20.0 | teeth      |
+| v0.21.0 | teeth      |
+| v0.22.0 | uptake     |
 
 Please squash your changes into a single commit using a command like `git rebase -i upstream/<wip-branch>`.
 
@@ -89,15 +89,6 @@ Requires [Valgrind](http://valgrind.org/).
 npm run test-leak
 ```
 
-### Packaging tests
-
-Tests the installation on a number of Linux-based operating systems.
-Requires docker.
-
-```sh
-npm run test-packaging
-```
-
 ## Finally
 
 Please feel free to ask any questions via a

README.md

@@ -4,6 +4,10 @@
 npm install sharp
 ```
 
+```sh
+yarn add sharp
+```
+
 The typical use case for this high speed Node.js module
 is to convert large images in common formats to
 smaller, web-friendly JPEG, PNG and WebP images of varying dimensions.
@@ -17,8 +21,9 @@ Lanczos resampling ensures quality is not sacrificed for speed.
 As well as image resizing, operations such as
 rotation, extraction, compositing and gamma correction are available.
 
-OS X, Windows (x64), Linux (x64, ARM) systems do not require
-the installation of any external runtime dependencies.
+Most modern 64-bit OS X, Windows and Linux (glibc) systems running
+Node versions 4, 6, 8 and 10
+do not require any additional install or runtime dependencies.
 
 ## Examples
 
@@ -43,7 +48,7 @@ sharp('input.jpg')
 ```
 
 ```javascript
-const roundedCorners = new Buffer(
+const roundedCorners = Buffer.from(
   '<svg><rect x="0" y="0" width="200" height="200" rx="50" ry="50"/></svg>'
 );
 

appveyor.yml

@@ -7,10 +7,10 @@ environment:
   - nodejs_version: "4"
   - nodejs_version: "6"
   - nodejs_version: "8"
-  - nodejs_version: "9"
+  - nodejs_version: "10"
 install:
   - ps: Install-Product node $env:nodejs_version x64
-  - npm install -g npm@5.3.x
+  - npm install -g npm@5
   - npm install
 test_script:
   - npm test

binding.gyp

@@ -5,9 +5,6 @@
       ['OS == "win"', {
         # Build libvips C++ binding for Windows due to MSVC std library ABI changes
         'type': 'shared_library',
-        'variables': {
-          'download_vips': '<!(node -e "require(\'./binding\').download_vips()")'
-        },
         'defines': [
           'VIPS_CPLUSPLUS_EXPORTS',
           '_ALLOW_KEYWORD_MACROS'
@@ -49,37 +46,15 @@
     'dependencies': [
       'libvips-cpp'
     ],
-    # Nested variables "pattern" borrowed from http://src.chromium.org/viewvc/chrome/trunk/src/build/common.gypi
     'variables': {
-      'variables': {
-        'variables': {
-          'conditions': [
-            ['OS != "win"', {
-              # Build the PKG_CONFIG_PATH environment variable with all possible combinations
-              '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'
-            }, {
-              'pkg_config_path': ''
-            }]
-          ],
-        },
-        'conditions': [
-          ['OS != "win"', {
-            # Which version, if any, of libvips is available globally via pkg-config?
-            'global_vips_version': '<!(PKG_CONFIG_PATH="<(pkg_config_path)" pkg-config --modversion vips-cpp 2>/dev/null || true)'
-          }, {
-            'global_vips_version': ''
-          }]
-        ],
-        'pkg_config_path%': '<(pkg_config_path)'
-      },
-      'pkg_config_path%': '<(pkg_config_path)',
       'runtime_link%': 'shared',
       'conditions': [
         ['OS != "win"', {
-          # Does the globally available version of libvips, if any, meet the minimum version requirement?
-          'use_global_vips': '<!(GLOBAL_VIPS_VERSION="<(global_vips_version)" node -e "require(\'./binding\').use_global_vips()")'
+          'pkg_config_path': '<!(node -e "console.log(require(\'./lib/libvips\').pkgConfigPath())")',
+          'use_global_libvips': '<!(node -e "console.log(Boolean(require(\'./lib/libvips\').useGlobalLibvips()).toString())")'
         }, {
-          'use_global_vips': ''
+          'pkg_config_path': '',
+          'use_global_libvips': ''
         }]
       ]
     },
@@ -96,7 +71,7 @@
       '<!(node -e "require(\'nan\')")'
     ],
     'conditions': [
-      ['use_global_vips == "true"', {
+      ['use_global_libvips == "true"', {
         # Use pkg-config for include and lib
         'include_dirs': ['<!@(PKG_CONFIG_PATH="<(pkg_config_path)" pkg-config --cflags-only-I vips-cpp vips glib-2.0 | sed s\/-I//g)'],
         'conditions': [
@@ -113,7 +88,7 @@
           }]
         ]
       }, {
-        # Attempt to download pre-built libvips and install locally within node_modules
+        # Use pre-built libvips stored locally within node_modules
         'include_dirs': [
           'vendor/include',
           'vendor/include/glib-2.0',
@@ -131,9 +106,6 @@
             ]
           }],
           ['OS == "mac"', {
-            'variables': {
-              'download_vips': '<!(node -e "require(\'./binding\').download_vips()")'
-            },
             'libraries': [
               '../vendor/lib/libvips-cpp.42.dylib',
               '../vendor/lib/libvips.42.dylib',
@@ -144,9 +116,6 @@
             ]
           }],
           ['OS == "linux"', {
-            'variables': {
-              'download_vips': '<!(node -e "require(\'./binding\').download_vips()")'
-            },
             'defines': [
               '_GLIBCXX_USE_CXX11_ABI=0'
             ],
@@ -219,65 +188,5 @@
         ]
       }
     },
-  }, {
-    'target_name': 'win_copy_dlls',
-    'type': 'none',
-    'dependencies': [
-      'sharp'
-    ],
-    'conditions': [
-      ['OS == "win"', {
-        # Windows lacks support for rpath
-        'copies': [{
-          'destination': 'build/Release',
-          'files': [
-            'vendor/lib/libasprintf-0.dll',
-            'vendor/lib/libcairo-2.dll',
-            'vendor/lib/libcairo-gobject-2.dll',
-            'vendor/lib/libcairo-script-interpreter-2.dll',
-            'vendor/lib/libcharset-1.dll',
-            'vendor/lib/libcroco-0.6-3.dll',
-            'vendor/lib/libexif-12.dll',
-            'vendor/lib/libexpat-1.dll',
-            'vendor/lib/libffi-6.dll',
-            'vendor/lib/libfftw3-3.dll',
-            'vendor/lib/libfontconfig-1.dll',
-            'vendor/lib/libfreetype-6.dll',
-            'vendor/lib/libgcc_s_seh-1.dll',
-            'vendor/lib/libgdk_pixbuf-2.0-0.dll',
-            'vendor/lib/libgettextlib-0-19-8.dll',
-            'vendor/lib/libgettextpo-1.dll',
-            'vendor/lib/libgettextsrc-0-19-8.dll',
-            'vendor/lib/libgif-7.dll',
-            'vendor/lib/libgio-2.0-0.dll',
-            'vendor/lib/libglib-2.0-0.dll',
-            'vendor/lib/libgmodule-2.0-0.dll',
-            'vendor/lib/libgobject-2.0-0.dll',
-            'vendor/lib/libgsf-1-114.dll',
-            'vendor/lib/libgthread-2.0-0.dll',
-            'vendor/lib/libharfbuzz-0.dll',
-            'vendor/lib/libiconv-2.dll',
-            'vendor/lib/libintl-9.dll',
-            'vendor/lib/libjpeg-62.dll',
-            'vendor/lib/liblcms2-2.dll',
-            'vendor/lib/libpango-1.0-0.dll',
-            'vendor/lib/libpangocairo-1.0-0.dll',
-            'vendor/lib/libpangoft2-1.0-0.dll',
-            'vendor/lib/libpangowin32-1.0-0.dll',
-            'vendor/lib/libpixman-1-0.dll',
-            'vendor/lib/libpng16-16.dll',
-            'vendor/lib/libquadmath-0.dll',
-            'vendor/lib/librsvg-2-2.dll',
-            'vendor/lib/libssp-0.dll',
-            'vendor/lib/libstdc++-6.dll',
-            'vendor/lib/libtiff-5.dll',
-            'vendor/lib/libvips-42.dll',
-            'vendor/lib/libwebp-7.dll',
-            'vendor/lib/libxml2-2.dll',
-            'vendor/lib/zlib1.dll'
-          ]
-        }]
-      }]
-    ]
   }]
 }

binding.js

@@ -1,108 +0,0 @@
-'use strict';
-
-const fs = require('fs');
-const os = require('os');
-const path = require('path');
-
-const simpleGet = require('simple-get');
-const semver = require('semver');
-const tar = require('tar');
-const detectLibc = require('detect-libc');
-
-const agent = require('./lib/agent');
-const platform = require('./lib/platform');
-
-// Use NPM-provided environment variable where available, falling back to require-based method for Electron
-const minimumLibvipsVersion = process.env.npm_package_config_libvips || require('./package.json').config.libvips;
-
-const distBaseUrl = process.env.SHARP_DIST_BASE_URL || `https://github.com/lovell/sharp-libvips/releases/download/v${minimumLibvipsVersion}/`;
-
-// -- Helpers
-
-const unpack = function (tarPath, done) {
-  const vendorPath = path.join(__dirname, 'vendor');
-  fs.mkdirSync(vendorPath);
-  tar
-    .extract({
-      file: tarPath,
-      cwd: vendorPath,
-      strict: true
-    })
-    .then(done)
-    .catch(error);
-};
-
-const error = function (msg) {
-  if (msg instanceof Error) {
-    msg = msg.message;
-  }
-  process.stderr.write(`sharp: ${msg}\n`);
-  process.exit(1);
-};
-
-// -- Binary downloaders
-
-module.exports.download_vips = function () {
-  // Check for existing vendored binaries and verify platform matches
-  const currentPlatformId = platform();
-  try {
-    const vendorPlatformId = require(path.join(__dirname, 'vendor', 'platform.json'));
-    if (currentPlatformId === vendorPlatformId) {
-      return;
-    } else {
-      error(`'${vendorPlatformId}' binaries cannot be used on the '${currentPlatformId}' platform. Please remove the 'node_modules/sharp/vendor' directory and run 'npm install'.`);
-    }
-  } catch (err) {}
-  // Ensure Intel 64-bit or ARM
-  const arch = process.env.npm_config_arch || process.arch;
-  if (arch === 'ia32') {
-    error(`Intel Architecture 32-bit systems require manual installation of libvips >= ${minimumLibvipsVersion} - please see http://sharp.pixelplumbing.com/page/install`);
-  }
-  // Ensure glibc Linux
-  if (detectLibc.isNonGlibcLinux) {
-    error(`Use with ${detectLibc.family} libc requires manual installation of libvips >= ${minimumLibvipsVersion} - please see http://sharp.pixelplumbing.com/page/install`);
-  }
-  // Ensure glibc >= 2.13
-  if (detectLibc.family === detectLibc.GLIBC && detectLibc.version && semver.lt(`${detectLibc.version}.0`, '2.13.0')) {
-    error(`Use with glibc version ${detectLibc.version} requires manual installation of libvips >= ${minimumLibvipsVersion} - please see http://sharp.pixelplumbing.com/page/install`);
-  }
-  // Arch/platform-specific .tar.gz
-  const tarFilename = ['libvips', minimumLibvipsVersion, currentPlatformId].join('-') + '.tar.gz';
-  // Download to per-process temporary file
-  const tarPathTemp = path.join(os.tmpdir(), `${process.pid}-${tarFilename}`);
-  const tmpFile = fs.createWriteStream(tarPathTemp).on('close', function () {
-    unpack(tarPathTemp, function () {
-      // Attempt to remove temporary file
-      try {
-        fs.unlinkSync(tarPathTemp);
-      } catch (err) {}
-    });
-  });
-  const url = distBaseUrl + tarFilename;
-  const simpleGetOpt = {
-    url: url,
-    agent: agent()
-  };
-  simpleGet(simpleGetOpt, function (err, response) {
-    if (err) {
-      error(`${url} download failed: ${err.message}`);
-    }
-    if (response.statusCode !== 200) {
-      error(`${url} download failed: status ${response.statusCode}`);
-    }
-    response.pipe(tmpFile);
-  });
-};
-
-module.exports.use_global_vips = function () {
-  const globalVipsVersion = process.env.GLOBAL_VIPS_VERSION;
-  if (globalVipsVersion) {
-    const useGlobalVips = semver.gte(
-      globalVipsVersion,
-      minimumLibvipsVersion
-    );
-    process.stdout.write(useGlobalVips ? 'true' : 'false');
-  } else {
-    process.stdout.write('false');
-  }
-};

docs/api-channel.md

@@ -1,20 +1,30 @@
 <!-- Generated by documentation.js. Update this documentation by updating the source code. -->
 
-### Table of Contents
+## removeAlpha
 
--   [extractChannel](#extractchannel)
--   [joinChannel](#joinchannel)
--   [bandbool](#bandbool)
+Remove alpha channel, if any. This is a no-op if the image does not have an alpha channel.
+
+### Examples
+
+```javascript
+sharp('rgba.png')
+  .removeAlpha()
+  .toFile('rgb.png', function(err, info) {
+    // rgb.png is a 3 channel image without an alpha channel
+  });
+```
+
+Returns **Sharp** 
 
 ## extractChannel
 
 Extract a single channel from a multi-channel image.
 
-**Parameters**
+### Parameters
 
--   `channel` **([Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number) \| [String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String))** zero-indexed band number to extract, or `red`, `green` or `blue` as alternative to `0`, `1` or `2` respectively.
+-   `channel` **([Number][1] \| [String][2])** zero-indexed band number to extract, or `red`, `green` or `blue` as alternative to `0`, `1` or `2` respectively.
 
-**Examples**
+### Examples
 
 ```javascript
 sharp(input)
@@ -25,7 +35,7 @@ sharp(input)
    });
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid channel
+-   Throws **[Error][3]** Invalid channel
 
 Returns **Sharp** 
 
@@ -42,13 +52,13 @@ Channel ordering follows vips convention:
 Buffers may be any of the image formats supported by sharp: JPEG, PNG, WebP, GIF, SVG, TIFF or raw pixel image data.
 For raw pixel input, the `options` object should contain a `raw` attribute, which follows the format of the attribute of the same name in the `sharp()` constructor.
 
-**Parameters**
+### Parameters
 
--   `images` **([Array](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array)&lt;([String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String) \| [Buffer](https://nodejs.org/api/buffer.html))> | [String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String) \| [Buffer](https://nodejs.org/api/buffer.html))** one or more images (file paths, Buffers).
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** image options, see `sharp()` constructor.
+-   `images` **([Array][4]&lt;([String][2] \| [Buffer][5])> | [String][2] \| [Buffer][5])** one or more images (file paths, Buffers).
+-   `options` **[Object][6]** image options, see `sharp()` constructor.
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][3]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -56,11 +66,11 @@ Returns **Sharp**
 
 Perform a bitwise boolean operation on all input image channels (bands) to produce a single channel output image.
 
-**Parameters**
+### Parameters
 
--   `boolOp` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** one of `and`, `or` or `eor` to perform that bitwise operation, like the C logic operators `&`, `|` and `^` respectively.
+-   `boolOp` **[String][2]** one of `and`, `or` or `eor` to perform that bitwise operation, like the C logic operators `&`, `|` and `^` respectively.
 
-**Examples**
+### Examples
 
 ```javascript
 sharp('3-channel-rgb-input.png')
@@ -72,6 +82,18 @@ sharp('3-channel-rgb-input.png')
   });
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][3]** Invalid parameters
 
 Returns **Sharp** 
+
+[1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array
+
+[5]: https://nodejs.org/api/buffer.html
+
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object

docs/api-colour.md

@@ -1,13 +1,5 @@
 <!-- Generated by documentation.js. Update this documentation by updating the source code. -->
 
-### Table of Contents
-
--   [background](#background)
--   [greyscale](#greyscale)
--   [grayscale](#grayscale)
--   [toColourspace](#tocolourspace)
--   [toColorspace](#tocolorspace)
-
 ## background
 
 Set the background for the `embed`, `flatten` and `extend` operations.
@@ -17,12 +9,26 @@ Delegates to the _color_ module, which can throw an Error
 but is liberal in what it accepts, clipping values to sensible min/max.
 The alpha value is a float between `0` (transparent) and `1` (opaque).
 
-**Parameters**
+### Parameters
 
--   `rgba` **([String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String) \| [Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object))** parsed by the [color](https://www.npmjs.org/package/color) module to extract values for red, green, blue and alpha.
+-   `rgba` **([String][1] \| [Object][2])** parsed by the [color][3] module to extract values for red, green, blue and alpha.
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameter
+-   Throws **[Error][4]** Invalid parameter
+
+Returns **Sharp** 
+
+## tint
+
+Tint the image using the provided chroma while preserving the image luminance.
+An alpha channel may be present and will be unchanged by the operation.
+
+### Parameters
+
+-   `rgb` **([String][1] \| [Object][2])** parsed by the [color][3] module to extract chroma values.
+
+
+-   Throws **[Error][4]** Invalid parameter
 
 Returns **Sharp** 
 
@@ -35,9 +41,9 @@ This may be overridden by other sharp operations such as `toColourspace('b-w')`,
 which will produce an output image containing one color channel.
 An alpha channel may be present, and will be unchanged by the operation.
 
-**Parameters**
+### Parameters
 
--   `greyscale` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `true`)
+-   `greyscale` **[Boolean][5]**  (optional, default `true`)
 
 Returns **Sharp** 
 
@@ -45,9 +51,9 @@ Returns **Sharp**
 
 Alternative spelling of `greyscale`.
 
-**Parameters**
+### Parameters
 
--   `grayscale` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `true`)
+-   `grayscale` **[Boolean][5]**  (optional, default `true`)
 
 Returns **Sharp** 
 
@@ -56,12 +62,12 @@ Returns **Sharp**
 Set the output colourspace.
 By default output image will be web-friendly sRGB, with additional channels interpreted as alpha channels.
 
-**Parameters**
+### Parameters
 
--   `colourspace` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)?** output colourspace e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...](https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L568)
+-   `colourspace` **[String][1]?** output colourspace e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...][6]
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][4]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -69,11 +75,23 @@ Returns **Sharp**
 
 Alternative spelling of `toColourspace`.
 
-**Parameters**
+### Parameters
 
--   `colorspace` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)?** output colorspace.
+-   `colorspace` **[String][1]?** output colorspace.
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][4]** Invalid parameters
 
 Returns **Sharp** 
+
+[1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[3]: https://www.npmjs.org/package/color
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[6]: https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L568

docs/api-composite.md

@@ -1,9 +1,5 @@
 <!-- Generated by documentation.js. Update this documentation by updating the source code. -->
 
-### Table of Contents
-
--   [overlayWith](#overlaywith)
-
 ## overlayWith
 
 Overlay (composite) an image over the processed (resized, extracted etc.) image.
@@ -13,27 +9,27 @@ If both `top` and `left` options are provided, they take precedence over `gravit
 
 If the overlay image contains an alpha channel then composition with premultiplication will occur.
 
-**Parameters**
+### Parameters
 
--   `overlay` **([Buffer](https://nodejs.org/api/buffer.html) \| [String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String))** Buffer containing image data or String containing the path to an image file.
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** 
-    -   `options.gravity` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** gravity at which to place the overlay. (optional, default `'centre'`)
-    -   `options.top` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** the pixel offset from the top edge.
-    -   `options.left` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** the pixel offset from the left edge.
-    -   `options.tile` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** set to true to repeat the overlay image across the entire image with the given `gravity`. (optional, default `false`)
-    -   `options.cutout` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** set to true to apply only the alpha channel of the overlay image to the input image, giving the appearance of one image being cut out of another. (optional, default `false`)
-    -   `options.density` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** integral number representing the DPI for vector overlay image. (optional, default `72`)
-    -   `options.raw` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** describes overlay when using raw pixel data.
-        -   `options.raw.width` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-        -   `options.raw.height` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-        -   `options.raw.channels` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-    -   `options.create` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** describes a blank overlay to be created.
-        -   `options.create.width` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-        -   `options.create.height` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-        -   `options.create.channels` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 3-4
-        -   `options.create.background` **([String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String) \| [Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object))?** parsed by the [color](https://www.npmjs.org/package/color) module to extract values for red, green, blue and alpha.
+-   `overlay` **([Buffer][1] \| [String][2])** Buffer containing image data or String containing the path to an image file.
+-   `options` **[Object][3]?** 
+    -   `options.gravity` **[String][2]** gravity at which to place the overlay. (optional, default `'centre'`)
+    -   `options.top` **[Number][4]?** the pixel offset from the top edge.
+    -   `options.left` **[Number][4]?** the pixel offset from the left edge.
+    -   `options.tile` **[Boolean][5]** set to true to repeat the overlay image across the entire image with the given `gravity`. (optional, default `false`)
+    -   `options.cutout` **[Boolean][5]** set to true to apply only the alpha channel of the overlay image to the input image, giving the appearance of one image being cut out of another. (optional, default `false`)
+    -   `options.density` **[Number][4]** integral number representing the DPI for vector overlay image. (optional, default `72`)
+    -   `options.raw` **[Object][3]?** describes overlay when using raw pixel data.
+        -   `options.raw.width` **[Number][4]?** 
+        -   `options.raw.height` **[Number][4]?** 
+        -   `options.raw.channels` **[Number][4]?** 
+    -   `options.create` **[Object][3]?** describes a blank overlay to be created.
+        -   `options.create.width` **[Number][4]?** 
+        -   `options.create.height` **[Number][4]?** 
+        -   `options.create.channels` **[Number][4]?** 3-4
+        -   `options.create.background` **([String][2] \| [Object][3])?** parsed by the [color][6] module to extract values for red, green, blue and alpha.
 
-**Examples**
+### Examples
 
 ```javascript
 sharp('input.png')
@@ -44,8 +40,7 @@ sharp('input.png')
   .overlayWith('overlay.png', { gravity: sharp.gravity.southeast } )
   .sharpen()
   .withMetadata()
-  .quality(90)
-  .webp()
+  .webp( { quality: 90 } )
   .toBuffer()
   .then(function(outputBuffer) {
     // outputBuffer contains upside down, 300px wide, alpha channel flattened
@@ -54,6 +49,20 @@ sharp('input.png')
   });
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][7]** Invalid parameters
 
 Returns **Sharp** 
+
+[1]: https://nodejs.org/api/buffer.html
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[6]: https://www.npmjs.org/package/color
+
+[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error

docs/api-constructor.md

@@ -1,36 +1,30 @@
 <!-- Generated by documentation.js. Update this documentation by updating the source code. -->
 
-### Table of Contents
-
--   [Sharp](#sharp)
-    -   [format](#format)
-    -   [versions](#versions)
--   [queue](#queue)
-
 ## Sharp
 
-**Parameters**
+### Parameters
 
--   `input` **([Buffer](https://nodejs.org/api/buffer.html) \| [String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String))?** if present, can be
+-   `input` **([Buffer][1] \| [String][2])?** if present, can be
      a Buffer containing JPEG, PNG, WebP, GIF, SVG, TIFF or raw pixel image data, or
      a String containing the path to an JPEG, PNG, WebP, GIF, SVG or TIFF image file.
      JPEG, PNG, WebP, GIF, SVG, TIFF or raw pixel image data can be streamed into the object when not present.
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** if present, is an Object with optional attributes.
-    -   `options.failOnError` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** by default apply a "best effort"
+-   `options` **[Object][3]?** if present, is an Object with optional attributes.
+    -   `options.failOnError` **[Boolean][4]** by default apply a "best effort"
          to decode images, even if the data is corrupt or invalid. Set this flag to true
          if you'd rather halt processing and raise an error when loading invalid images. (optional, default `false`)
-    -   `options.density` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** integral number representing the DPI for vector images. (optional, default `72`)
-    -   `options.raw` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** describes raw pixel input image data. See `raw()` for pixel ordering.
-        -   `options.raw.width` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-        -   `options.raw.height` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-        -   `options.raw.channels` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 1-4
-    -   `options.create` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** describes a new image to be created.
-        -   `options.create.width` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-        -   `options.create.height` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-        -   `options.create.channels` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 3-4
-        -   `options.create.background` **([String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String) \| [Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object))?** parsed by the [color](https://www.npmjs.org/package/color) module to extract values for red, green, blue and alpha.
+    -   `options.density` **[Number][5]** integral number representing the DPI for vector images. (optional, default `72`)
+    -   `options.page` **[Number][5]** page number to extract for multi-page input (GIF, TIFF) (optional, default `0`)
+    -   `options.raw` **[Object][3]?** describes raw pixel input image data. See `raw()` for pixel ordering.
+        -   `options.raw.width` **[Number][5]?** 
+        -   `options.raw.height` **[Number][5]?** 
+        -   `options.raw.channels` **[Number][5]?** 1-4
+    -   `options.create` **[Object][3]?** describes a new image to be created.
+        -   `options.create.width` **[Number][5]?** 
+        -   `options.create.height` **[Number][5]?** 
+        -   `options.create.channels` **[Number][5]?** 3-4
+        -   `options.create.background` **([String][2] \| [Object][3])?** parsed by the [color][6] module to extract values for red, green, blue and alpha.
 
-**Examples**
+### Examples
 
 ```javascript
 sharp('input.jpg')
@@ -61,7 +55,7 @@ sharp({
     width: 300,
     height: 200,
     channels: 4,
-    background: { r: 255, g: 0, b: 0, alpha: 128 }
+    background: { r: 255, g: 0, b: 0, alpha: 0.5 }
   }
 })
 .png()
@@ -69,27 +63,27 @@ sharp({
 .then( ... );
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][7]** Invalid parameters
 
-Returns **[Sharp](#sharp)** 
+Returns **[Sharp][8]** 
 
 ### format
 
 An Object containing nested boolean values representing the available input and output formats/methods.
 
-**Examples**
+#### Examples
 
 ```javascript
 console.log(sharp.format);
 ```
 
-Returns **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** 
+Returns **[Object][3]** 
 
 ### versions
 
 An Object containing the version numbers of libvips and its dependencies.
 
-**Examples**
+#### Examples
 
 ```javascript
 console.log(sharp.versions);
@@ -102,10 +96,26 @@ An EventEmitter that emits a `change` event when a task is either:
 -   queued, waiting for _libuv_ to provide a worker thread
 -   complete
 
-**Examples**
+### Examples
 
 ```javascript
 sharp.queue.on('change', function(queueLength) {
   console.log('Queue contains ' + queueLength + ' task(s)');
 });
 ```
+
+[1]: https://nodejs.org/api/buffer.html
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[6]: https://www.npmjs.org/package/color
+
+[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[8]: #sharp

docs/api-input.md

@@ -1,20 +1,12 @@
 <!-- Generated by documentation.js. Update this documentation by updating the source code. -->
 
-### Table of Contents
-
--   [clone](#clone)
--   [metadata](#metadata)
--   [stats](#stats)
--   [limitInputPixels](#limitinputpixels)
--   [sequentialRead](#sequentialread)
-
 ## clone
 
 Take a "snapshot" of the Sharp instance, returning a new instance.
 Cloned instances inherit the input of their parent instance.
 This allows multiple output Streams and therefore multiple processing pipelines to share a single input Stream.
 
-**Examples**
+### Examples
 
 ```javascript
 const pipeline = sharp().rotate();
@@ -33,25 +25,25 @@ Fast access to (uncached) image metadata without decoding any compressed image d
 A Promises/A+ promise is returned when `callback` is not provided.
 
 -   `format`: Name of decoder used to decompress image data e.g. `jpeg`, `png`, `webp`, `gif`, `svg`
--   `width`: Number of pixels wide
--   `height`: Number of pixels high
--   `space`: Name of colour space interpretation e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...](https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L636)
+-   `width`: Number of pixels wide (EXIF orientation is not taken into consideration)
+-   `height`: Number of pixels high (EXIF orientation is not taken into consideration)
+-   `space`: Name of colour space interpretation e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...][1]
 -   `channels`: Number of bands e.g. `3` for sRGB, `4` for CMYK
--   `depth`: Name of pixel depth format e.g. `uchar`, `char`, `ushort`, `float` [...](https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L672)
+-   `depth`: Name of pixel depth format e.g. `uchar`, `char`, `ushort`, `float` [...][2]
 -   `density`: Number of pixels per inch (DPI), if present
 -   `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
+-   `icc`: Buffer containing raw [ICC][3] profile data, if present
 -   `iptc`: Buffer containing raw IPTC data, if present
 -   `xmp`: Buffer containing raw XMP data, if present
 
-**Parameters**
+### Parameters
 
--   `callback` **[Function](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function)?** called with the arguments `(err, metadata)`
+-   `callback` **[Function][4]?** called with the arguments `(err, metadata)`
 
-**Examples**
+### Examples
 
 ```javascript
 const image = sharp(inputJpg);
@@ -68,7 +60,7 @@ image
   });
 ```
 
-Returns **([Promise](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise)&lt;[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)> | Sharp)** 
+Returns **([Promise][5]&lt;[Object][6]> | Sharp)** 
 
 ## stats
 
@@ -87,12 +79,13 @@ A Promise is returned when `callback` is not provided.
     -   `maxX` (x-coordinate of one of the pixel where the maximum lies)
     -   `maxY` (y-coordinate of one of the pixel where the maximum lies)
 -   `isOpaque`: Value to identify if the image is opaque or transparent, based on the presence and use of alpha channel
+-   `entropy`: Histogram-based estimation of greyscale entropy, discarding alpha channel if any (experimental)
 
-**Parameters**
+### Parameters
 
--   `callback` **[Function](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function)?** called with the arguments `(err, stats)`
+-   `callback` **[Function][4]?** called with the arguments `(err, stats)`
 
-**Examples**
+### Examples
 
 ```javascript
 const image = sharp(inputJpg);
@@ -103,7 +96,7 @@ image
   });
 ```
 
-Returns **[Promise](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise)&lt;[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)>** 
+Returns **[Promise][5]&lt;[Object][6]>** 
 
 ## limitInputPixels
 
@@ -111,12 +104,12 @@ Do not process input images where the number of pixels (width _ height) exceeds
 Assumes image dimensions contained in the input metadata can be trusted.
 The default limit is 268402689 (0x3FFF _ 0x3FFF) pixels.
 
-**Parameters**
+### Parameters
 
--   `limit` **([Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number) \| [Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean))** an integral Number of pixels, zero or false to remove limit, true to use default limit.
+-   `limit` **([Number][7] \| [Boolean][8])** an integral Number of pixels, zero or false to remove limit, true to use default limit.
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid limit
+-   Throws **[Error][9]** Invalid limit
 
 Returns **Sharp** 
 
@@ -127,8 +120,26 @@ This will reduce memory usage and can improve performance on some systems.
 
 The default behaviour _before_ function call is `false`, meaning the libvips access method is not sequential.
 
-**Parameters**
+### Parameters
 
--   `sequentialRead` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `true`)
+-   `sequentialRead` **[Boolean][8]**  (optional, default `true`)
 
 Returns **Sharp** 
+
+[1]: https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L636
+
+[2]: https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L672
+
+[3]: https://www.npmjs.com/package/icc
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise
+
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[8]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[9]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error

docs/api-operation.md

@@ -1,24 +1,5 @@
 <!-- Generated by documentation.js. Update this documentation by updating the source code. -->
 
-### Table of Contents
-
--   [rotate](#rotate)
--   [extract](#extract)
--   [flip](#flip)
--   [flop](#flop)
--   [sharpen](#sharpen)
--   [blur](#blur)
--   [extend](#extend)
--   [flatten](#flatten)
--   [trim](#trim)
--   [gamma](#gamma)
--   [negate](#negate)
--   [normalise](#normalise)
--   [normalize](#normalize)
--   [convolve](#convolve)
--   [threshold](#threshold)
--   [boolean](#boolean)
-
 ## rotate
 
 Rotate the output image by either an explicit angle
@@ -35,11 +16,11 @@ The use of `rotate` implies the removal of the EXIF `Orientation` tag, if any.
 Method order is important when both rotating and extracting regions,
 for example `rotate(x).extract(y)` will produce a different result to `extract(y).rotate(x)`.
 
-**Parameters**
+### Parameters
 
--   `angle` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** angle of rotation, must be a multiple of 90. (optional, default `auto`)
+-   `angle` **[Number][1]** angle of rotation, must be a multiple of 90. (optional, default `auto`)
 
-**Examples**
+### Examples
 
 ```javascript
 const pipeline = sharp()
@@ -53,7 +34,7 @@ const pipeline = sharp()
 readableStream.pipe(pipeline);
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][2]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -65,15 +46,15 @@ Extract a region of the image.
 -   Use `extract` after `resize` for post-resize extraction.
 -   Use `extract` before and after for both.
 
-**Parameters**
+### Parameters
 
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** 
-    -   `options.left` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** zero-indexed offset from left edge
-    -   `options.top` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** zero-indexed offset from top edge
-    -   `options.width` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** dimension of extracted image
-    -   `options.height` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** dimension of extracted image
+-   `options` **[Object][3]** 
+    -   `options.left` **[Number][1]** zero-indexed offset from left edge
+    -   `options.top` **[Number][1]** zero-indexed offset from top edge
+    -   `options.width` **[Number][1]** dimension of extracted image
+    -   `options.height` **[Number][1]** dimension of extracted image
 
-**Examples**
+### Examples
 
 ```javascript
 sharp(input)
@@ -93,7 +74,7 @@ sharp(input)
   });
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][2]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -102,9 +83,9 @@ Returns **Sharp**
 Flip the image about the vertical Y axis. This always occurs after rotation, if any.
 The use of `flip` implies the removal of the EXIF `Orientation` tag, if any.
 
-**Parameters**
+### Parameters
 
--   `flip` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `true`)
+-   `flip` **[Boolean][4]**  (optional, default `true`)
 
 Returns **Sharp** 
 
@@ -113,9 +94,9 @@ Returns **Sharp**
 Flop the image about the horizontal X axis. This always occurs after rotation, if any.
 The use of `flop` implies the removal of the EXIF `Orientation` tag, if any.
 
-**Parameters**
+### Parameters
 
--   `flop` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `true`)
+-   `flop` **[Boolean][4]**  (optional, default `true`)
 
 Returns **Sharp** 
 
@@ -126,14 +107,28 @@ When used without parameters, performs a fast, mild sharpen of the output image.
 When a `sigma` is provided, performs a slower, more accurate sharpen of the L channel in the LAB colour space.
 Separate control over the level of sharpening in "flat" and "jagged" areas is available.
 
-**Parameters**
+### Parameters
 
--   `sigma` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** the sigma of the Gaussian mask, where `sigma = 1 + radius / 2`.
--   `flat` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** the level of sharpening to apply to "flat" areas. (optional, default `1.0`)
--   `jagged` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** the level of sharpening to apply to "jagged" areas. (optional, default `2.0`)
+-   `sigma` **[Number][1]?** the sigma of the Gaussian mask, where `sigma = 1 + radius / 2`.
+-   `flat` **[Number][1]** the level of sharpening to apply to "flat" areas. (optional, default `1.0`)
+-   `jagged` **[Number][1]** the level of sharpening to apply to "jagged" areas. (optional, default `2.0`)
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][2]** Invalid parameters
+
+Returns **Sharp** 
+
+## median
+
+Apply median filter.
+When used without parameters the default window is 3x3.
+
+### Parameters
+
+-   `size` **[Number][1]** square mask size: size x size (optional, default `3`)
+
+
+-   Throws **[Error][2]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -143,12 +138,12 @@ Blur the image.
 When used without parameters, performs a fast, mild blur of the output image.
 When a `sigma` is provided, performs a slower, more accurate Gaussian blur.
 
-**Parameters**
+### Parameters
 
--   `sigma` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** a value between 0.3 and 1000 representing the sigma of the Gaussian mask, where `sigma = 1 + radius / 2`.
+-   `sigma` **[Number][1]?** a value between 0.3 and 1000 representing the sigma of the Gaussian mask, where `sigma = 1 + radius / 2`.
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][2]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -157,15 +152,15 @@ Returns **Sharp**
 Extends/pads the edges of the image with the colour provided to the `background` method.
 This operation will always occur after resizing and extraction, if any.
 
-**Parameters**
+### Parameters
 
--   `extend` **([Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number) \| [Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object))** single pixel count to add to all edges or an Object with per-edge counts
-    -   `extend.top` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-    -   `extend.left` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-    -   `extend.bottom` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-    -   `extend.right` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
+-   `extend` **([Number][1] \| [Object][3])** single pixel count to add to all edges or an Object with per-edge counts
+    -   `extend.top` **[Number][1]?** 
+    -   `extend.left` **[Number][1]?** 
+    -   `extend.bottom` **[Number][1]?** 
+    -   `extend.right` **[Number][1]?** 
 
-**Examples**
+### Examples
 
 ```javascript
 // Resize to 140 pixels wide, then add 10 transparent pixels
@@ -177,7 +172,7 @@ sharp(input)
   ...
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][2]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -185,9 +180,9 @@ Returns **Sharp**
 
 Merge alpha transparency channel, if any, with `background`.
 
-**Parameters**
+### Parameters
 
--   `flatten` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `true`)
+-   `flatten` **[Boolean][4]**  (optional, default `true`)
 
 Returns **Sharp** 
 
@@ -195,12 +190,12 @@ Returns **Sharp**
 
 Trim "boring" pixels from all edges that contain values within a percentage similarity of the top-left pixel.
 
-**Parameters**
+### Parameters
 
--   `tolerance` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** value between 1 and 99 representing the percentage similarity. (optional, default `10`)
+-   `tolerance` **[Number][1]** value between 1 and 99 representing the percentage similarity. (optional, default `10`)
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][2]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -212,12 +207,12 @@ This can improve the perceived brightness of a resized image in non-linear colou
 JPEG and WebP input images will not take advantage of the shrink-on-load performance optimisation
 when applying a gamma correction.
 
-**Parameters**
+### Parameters
 
--   `gamma` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** value between 1.0 and 3.0. (optional, default `2.2`)
+-   `gamma` **[Number][1]** value between 1.0 and 3.0. (optional, default `2.2`)
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][2]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -225,9 +220,9 @@ Returns **Sharp**
 
 Produce the "negative" of the image.
 
-**Parameters**
+### Parameters
 
--   `negate` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `true`)
+-   `negate` **[Boolean][4]**  (optional, default `true`)
 
 Returns **Sharp** 
 
@@ -235,9 +230,9 @@ Returns **Sharp**
 
 Enhance output image contrast by stretching its luminance to cover the full dynamic range.
 
-**Parameters**
+### Parameters
 
--   `normalise` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `true`)
+-   `normalise` **[Boolean][4]**  (optional, default `true`)
 
 Returns **Sharp** 
 
@@ -245,9 +240,9 @@ Returns **Sharp**
 
 Alternative spelling of normalise.
 
-**Parameters**
+### Parameters
 
--   `normalize` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `true`)
+-   `normalize` **[Boolean][4]**  (optional, default `true`)
 
 Returns **Sharp** 
 
@@ -255,16 +250,16 @@ Returns **Sharp**
 
 Convolve the image with the specified kernel.
 
-**Parameters**
+### Parameters
 
--   `kernel` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** 
-    -   `kernel.width` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** width of the kernel in pixels.
-    -   `kernel.height` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** width of the kernel in pixels.
-    -   `kernel.kernel` **[Array](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array)&lt;[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)>** Array of length `width*height` containing the kernel values.
-    -   `kernel.scale` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** the scale of the kernel in pixels. (optional, default `sum`)
-    -   `kernel.offset` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** the offset of the kernel in pixels. (optional, default `0`)
+-   `kernel` **[Object][3]** 
+    -   `kernel.width` **[Number][1]** width of the kernel in pixels.
+    -   `kernel.height` **[Number][1]** width of the kernel in pixels.
+    -   `kernel.kernel` **[Array][5]&lt;[Number][1]>** Array of length `width*height` containing the kernel values.
+    -   `kernel.scale` **[Number][1]** the scale of the kernel in pixels. (optional, default `sum`)
+    -   `kernel.offset` **[Number][1]** the offset of the kernel in pixels. (optional, default `0`)
 
-**Examples**
+### Examples
 
 ```javascript
 sharp(input)
@@ -280,7 +275,7 @@ sharp(input)
   });
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][2]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -288,15 +283,15 @@ Returns **Sharp**
 
 Any pixel value greather than or equal to the threshold value will be set to 255, otherwise it will be set to 0.
 
-**Parameters**
+### Parameters
 
--   `threshold` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** a value in the range 0-255 representing the level at which the threshold will be applied. (optional, default `128`)
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** 
-    -   `options.greyscale` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** convert to single channel greyscale. (optional, default `true`)
-    -   `options.grayscale` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** alternative spelling for greyscale. (optional, default `true`)
+-   `threshold` **[Number][1]** a value in the range 0-255 representing the level at which the threshold will be applied. (optional, default `128`)
+-   `options` **[Object][3]?** 
+    -   `options.greyscale` **[Boolean][4]** convert to single channel greyscale. (optional, default `true`)
+    -   `options.grayscale` **[Boolean][4]** alternative spelling for greyscale. (optional, default `true`)
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][2]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -307,17 +302,45 @@ Perform a bitwise boolean operation with operand image.
 This operation creates an output image where each pixel is the result of
 the selected bitwise boolean `operation` between the corresponding pixels of the input images.
 
-**Parameters**
+### Parameters
 
--   `operand` **([Buffer](https://nodejs.org/api/buffer.html) \| [String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String))** Buffer containing image data or String containing the path to an image file.
--   `operator` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** one of `and`, `or` or `eor` to perform that bitwise operation, like the C logic operators `&`, `|` and `^` respectively.
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** 
-    -   `options.raw` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** describes operand when using raw pixel data.
-        -   `options.raw.width` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-        -   `options.raw.height` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
-        -   `options.raw.channels` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
+-   `operand` **([Buffer][6] \| [String][7])** Buffer containing image data or String containing the path to an image file.
+-   `operator` **[String][7]** one of `and`, `or` or `eor` to perform that bitwise operation, like the C logic operators `&`, `|` and `^` respectively.
+-   `options` **[Object][3]?** 
+    -   `options.raw` **[Object][3]?** describes operand when using raw pixel data.
+        -   `options.raw.width` **[Number][1]?** 
+        -   `options.raw.height` **[Number][1]?** 
+        -   `options.raw.channels` **[Number][1]?** 
 
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][2]** Invalid parameters
 
 Returns **Sharp** 
+
+## linear
+
+Apply the linear formula a \* input + b to the image (levels adjustment)
+
+### Parameters
+
+-   `a` **[Number][1]** multiplier (optional, default `1.0`)
+-   `b` **[Number][1]** offset (optional, default `0.0`)
+
+
+-   Throws **[Error][2]** Invalid parameters
+
+Returns **Sharp** 
+
+[1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array
+
+[6]: https://nodejs.org/api/buffer.html
+
+[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String

docs/api-output.md

@@ -1,18 +1,5 @@
 <!-- Generated by documentation.js. Update this documentation by updating the source code. -->
 
-### Table of Contents
-
--   [toFile](#tofile)
--   [toBuffer](#tobuffer)
--   [withMetadata](#withmetadata)
--   [jpeg](#jpeg)
--   [png](#png)
--   [webp](#webp)
--   [tiff](#tiff)
--   [raw](#raw)
--   [toFormat](#toformat)
--   [tile](#tile)
-
 ## toFile
 
 Write output image data to a file.
@@ -23,18 +10,31 @@ Note that raw pixel data is only supported for buffer output.
 
 A `Promise` is returned when `callback` is not provided.
 
-**Parameters**
+### Parameters
 
--   `fileOut` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** the path to write the image data to.
--   `callback` **[Function](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function)?** called on completion with two arguments `(err, info)`.
+-   `fileOut` **[String][1]** the path to write the image data to.
+-   `callback` **[Function][2]?** called on completion with two arguments `(err, info)`.
     `info` contains the output image `format`, `size` (bytes), `width`, `height`,
     `channels` and `premultiplied` (indicating if premultiplication was used).
     When using a crop strategy also contains `cropOffsetLeft` and `cropOffsetTop`.
 
+### Examples
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+```javascript
+sharp(input)
+  .toFile('output.png', (err, info) => { ... });
+```
 
-Returns **[Promise](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise)&lt;[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)>** when no callback is provided
+```javascript
+sharp(input)
+  .toFile('output.png')
+  .then(info => { ... })
+  .catch(err => { ... });
+```
+
+-   Throws **[Error][3]** Invalid parameters
+
+Returns **[Promise][4]&lt;[Object][5]>** when no callback is provided
 
 ## toBuffer
 
@@ -52,13 +52,34 @@ By default, the format will match the input image, except GIF and SVG input whic
 
 A `Promise` is returned when `callback` is not provided.
 
-**Parameters**
+### Parameters
 
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** 
-    -   `options.resolveWithObject` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)?** Resolve the Promise with an Object containing `data` and `info` properties instead of resolving only with `data`.
--   `callback` **[Function](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function)?** 
+-   `options` **[Object][5]?** 
+    -   `options.resolveWithObject` **[Boolean][6]?** Resolve the Promise with an Object containing `data` and `info` properties instead of resolving only with `data`.
+-   `callback` **[Function][2]?** 
 
-Returns **[Promise](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise)&lt;[Buffer](https://nodejs.org/api/buffer.html)>** when no callback is provided
+### Examples
+
+```javascript
+sharp(input)
+  .toBuffer((err, data, info) => { ... });
+```
+
+```javascript
+sharp(input)
+  .toBuffer()
+  .then(data => { ... })
+  .catch(err => { ... });
+```
+
+```javascript
+sharp(input)
+  .toBuffer({ resolveWithObject: true })
+  .then(({ data, info }) => { ... })
+  .catch(err => { ... });
+```
+
+Returns **[Promise][4]&lt;[Buffer][7]>** when no callback is provided
 
 ## withMetadata
 
@@ -66,13 +87,21 @@ Include all metadata (EXIF, XMP, IPTC) from the input image in the output image.
 The default behaviour, when `withMetadata` is not used, is to strip all metadata and convert to the device-independent sRGB colour space.
 This will also convert to and add a web-friendly sRGB ICC profile.
 
-**Parameters**
+### Parameters
 
--   `withMetadata` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** 
-    -   `withMetadata.orientation` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** value between 1 and 8, used to update the EXIF `Orientation` tag.
+-   `withMetadata` **[Object][5]?** 
+    -   `withMetadata.orientation` **[Number][8]?** value between 1 and 8, used to update the EXIF `Orientation` tag.
 
+### Examples
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+```javascript
+sharp('input.jpg')
+  .withMetadata()
+  .toFile('output-with-metadata.jpg')
+  .then(info => { ... });
+```
+
+-   Throws **[Error][3]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -80,20 +109,35 @@ Returns **Sharp**
 
 Use these JPEG options for output image.
 
-**Parameters**
+### Parameters
 
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** output options
-    -   `options.quality` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** quality, integer 1-100 (optional, default `80`)
-    -   `options.progressive` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** use progressive (interlace) scan (optional, default `false`)
-    -   `options.chromaSubsampling` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** set to '4:4:4' to prevent chroma subsampling when quality &lt;= 90 (optional, default `'4:2:0'`)
-    -   `options.trellisQuantisation` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** apply trellis quantisation, requires mozjpeg (optional, default `false`)
-    -   `options.overshootDeringing` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** apply overshoot deringing, requires mozjpeg (optional, default `false`)
-    -   `options.optimiseScans` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** optimise progressive scans, forces progressive, requires mozjpeg (optional, default `false`)
-    -   `options.optimizeScans` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** alternative spelling of optimiseScans (optional, default `false`)
-    -   `options.force` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** force JPEG output, otherwise attempt to use input format (optional, default `true`)
+-   `options` **[Object][5]?** output options
+    -   `options.quality` **[Number][8]** quality, integer 1-100 (optional, default `80`)
+    -   `options.progressive` **[Boolean][6]** use progressive (interlace) scan (optional, default `false`)
+    -   `options.chromaSubsampling` **[String][1]** set to '4:4:4' to prevent chroma subsampling when quality &lt;= 90 (optional, default `'4:2:0'`)
+    -   `options.trellisQuantisation` **[Boolean][6]** apply trellis quantisation, requires mozjpeg (optional, default `false`)
+    -   `options.overshootDeringing` **[Boolean][6]** apply overshoot deringing, requires mozjpeg (optional, default `false`)
+    -   `options.optimiseScans` **[Boolean][6]** optimise progressive scans, forces progressive, requires mozjpeg (optional, default `false`)
+    -   `options.optimizeScans` **[Boolean][6]** alternative spelling of optimiseScans (optional, default `false`)
+    -   `options.optimiseCoding` **[Boolean][6]** optimise Huffman coding tables (optional, default `true`)
+    -   `options.optimizeCoding` **[Boolean][6]** alternative spelling of optimiseCoding (optional, default `true`)
+    -   `options.quantisationTable` **[Number][8]** quantization table to use, integer 0-8, requires mozjpeg (optional, default `0`)
+    -   `options.quantizationTable` **[Number][8]** alternative spelling of quantisationTable (optional, default `0`)
+    -   `options.force` **[Boolean][6]** force JPEG output, otherwise attempt to use input format (optional, default `true`)
 
+### Examples
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid options
+```javascript
+// Convert any input to very high quality JPEG output
+const data = await sharp(input)
+  .jpeg({
+    quality: 100,
+    chromaSubsampling: '4:4:4'
+  })
+  .toBuffer();
+```
+
+-   Throws **[Error][3]** Invalid options
 
 Returns **Sharp** 
 
@@ -101,16 +145,27 @@ Returns **Sharp**
 
 Use these PNG options for output image.
 
-**Parameters**
+PNG output is always full colour at 8 or 16 bits per pixel.
+Indexed PNG input at 1, 2 or 4 bits per pixel is converted to 8 bits per pixel.
 
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** 
-    -   `options.progressive` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** use progressive (interlace) scan (optional, default `false`)
-    -   `options.compressionLevel` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** zlib compression level, 0-9 (optional, default `9`)
-    -   `options.adaptiveFiltering` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** use adaptive row filtering (optional, default `false`)
-    -   `options.force` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** force PNG output, otherwise attempt to use input format (optional, default `true`)
+### Parameters
 
+-   `options` **[Object][5]?** 
+    -   `options.progressive` **[Boolean][6]** use progressive (interlace) scan (optional, default `false`)
+    -   `options.compressionLevel` **[Number][8]** zlib compression level, 0-9 (optional, default `9`)
+    -   `options.adaptiveFiltering` **[Boolean][6]** use adaptive row filtering (optional, default `false`)
+    -   `options.force` **[Boolean][6]** force PNG output, otherwise attempt to use input format (optional, default `true`)
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid options
+### Examples
+
+```javascript
+// Convert any input to PNG output
+const data = await sharp(input)
+  .png()
+  .toBuffer();
+```
+
+-   Throws **[Error][3]** Invalid options
 
 Returns **Sharp** 
 
@@ -118,17 +173,25 @@ Returns **Sharp**
 
 Use these WebP options for output image.
 
-**Parameters**
+### Parameters
 
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** output options
-    -   `options.quality` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** quality, integer 1-100 (optional, default `80`)
-    -   `options.alphaQuality` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** quality of alpha layer, integer 0-100 (optional, default `100`)
-    -   `options.lossless` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** use lossless compression mode (optional, default `false`)
-    -   `options.nearLossless` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** use near_lossless compression mode (optional, default `false`)
-    -   `options.force` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** force WebP output, otherwise attempt to use input format (optional, default `true`)
+-   `options` **[Object][5]?** output options
+    -   `options.quality` **[Number][8]** quality, integer 1-100 (optional, default `80`)
+    -   `options.alphaQuality` **[Number][8]** quality of alpha layer, integer 0-100 (optional, default `100`)
+    -   `options.lossless` **[Boolean][6]** use lossless compression mode (optional, default `false`)
+    -   `options.nearLossless` **[Boolean][6]** use near_lossless compression mode (optional, default `false`)
+    -   `options.force` **[Boolean][6]** force WebP output, otherwise attempt to use input format (optional, default `true`)
 
+### Examples
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid options
+```javascript
+// Convert any input to lossless WebP output
+const data = await sharp(input)
+  .webp({ lossless: true })
+  .toBuffer();
+```
+
+-   Throws **[Error][3]** Invalid options
 
 Returns **Sharp** 
 
@@ -136,19 +199,31 @@ Returns **Sharp**
 
 Use these TIFF options for output image.
 
-**Parameters**
+### Parameters
 
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** output options
-    -   `options.quality` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** quality, integer 1-100 (optional, default `80`)
-    -   `options.force` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** force TIFF output, otherwise attempt to use input format (optional, default `true`)
-    -   `options.compression` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** compression options: lzw, deflate, jpeg (optional, default `'jpeg'`)
-    -   `options.predictor` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** compression predictor options: none, horizontal, float (optional, default `'horizontal'`)
-    -   `options.xres` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** horizontal resolution in pixels/mm (optional, default `1.0`)
-    -   `options.yres` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** vertical resolution in pixels/mm (optional, default `1.0`)
-    -   `options.squash` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** squash 8-bit images down to 1 bit (optional, default `false`)
+-   `options` **[Object][5]?** output options
+    -   `options.quality` **[Number][8]** quality, integer 1-100 (optional, default `80`)
+    -   `options.force` **[Boolean][6]** force TIFF output, otherwise attempt to use input format (optional, default `true`)
+    -   `options.compression` **[Boolean][6]** compression options: lzw, deflate, jpeg, ccittfax4 (optional, default `'jpeg'`)
+    -   `options.predictor` **[Boolean][6]** compression predictor options: none, horizontal, float (optional, default `'horizontal'`)
+    -   `options.xres` **[Number][8]** horizontal resolution in pixels/mm (optional, default `1.0`)
+    -   `options.yres` **[Number][8]** vertical resolution in pixels/mm (optional, default `1.0`)
+    -   `options.squash` **[Boolean][6]** squash 8-bit images down to 1 bit (optional, default `false`)
 
+### Examples
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid options
+```javascript
+// Convert SVG input to LZW-compressed, 1 bit per pixel TIFF output
+sharp('input.svg')
+  .tiff({
+    compression: 'lzw',
+    squash: true
+  })
+  .toFile('1-bpp-output.tiff')
+  .then(info => { ... });
+```
+
+-   Throws **[Error][3]** Invalid options
 
 Returns **Sharp** 
 
@@ -156,19 +231,36 @@ Returns **Sharp**
 
 Force output to be raw, uncompressed uint8 pixel data.
 
+### Examples
+
+```javascript
+// Extract raw RGB pixel data from JPEG input
+const { data, info } = await sharp('input.jpg')
+  .raw()
+  .toBuffer({ resolveWithObject: true });
+```
+
 Returns **Sharp** 
 
 ## toFormat
 
 Force output to a given format.
 
-**Parameters**
+### Parameters
 
--   `format` **([String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String) \| [Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object))** as a String or an Object with an 'id' attribute
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** output options
+-   `format` **([String][1] \| [Object][5])** as a String or an Object with an 'id' attribute
+-   `options` **[Object][5]** output options
 
+### Examples
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** unsupported format or options
+```javascript
+// Convert any input to PNG output
+const data = await sharp(input)
+  .toFormat('png')
+  .toBuffer();
+```
+
+-   Throws **[Error][3]** unsupported format or options
 
 Returns **Sharp** 
 
@@ -178,15 +270,19 @@ Use tile-based deep zoom (image pyramid) output.
 Set the format and options for tile images via the `toFormat`, `jpeg`, `png` or `webp` functions.
 Use a `.zip` or `.szi` file extension with `toFile` to write to a compressed archive file format.
 
-**Parameters**
+Warning: multiple sharp instances concurrently producing tile output can expose a possible race condition in some versions of libgsf.
 
--   `tile` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** 
-    -   `tile.size` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** tile size in pixels, a value between 1 and 8192. (optional, default `256`)
-    -   `tile.overlap` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** tile overlap in pixels, a value between 0 and 8192. (optional, default `0`)
-    -   `tile.container` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** tile container, with value `fs` (filesystem) or `zip` (compressed file). (optional, default `'fs'`)
-    -   `tile.layout` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** filesystem layout, possible values are `dz`, `zoomify` or `google`. (optional, default `'dz'`)
+### Parameters
 
-**Examples**
+-   `tile` **[Object][5]?** 
+    -   `tile.size` **[Number][8]** tile size in pixels, a value between 1 and 8192. (optional, default `256`)
+    -   `tile.overlap` **[Number][8]** tile overlap in pixels, a value between 0 and 8192. (optional, default `0`)
+    -   `tile.angle` **[Number][8]** tile angle of rotation, must be a multiple of 90. (optional, default `0`)
+    -   `tile.depth` **[String][1]?** how deep to make the pyramid, possible values are `onepixel`, `onetile` or `one`, default based on layout.
+    -   `tile.container` **[String][1]** tile container, with value `fs` (filesystem) or `zip` (compressed file). (optional, default `'fs'`)
+    -   `tile.layout` **[String][1]** filesystem layout, possible values are `dz`, `zoomify` or `google`. (optional, default `'dz'`)
+
+### Examples
 
 ```javascript
 sharp('input.tiff')
@@ -200,6 +296,22 @@ sharp('input.tiff')
   });
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][3]** Invalid parameters
 
 Returns **Sharp** 
+
+[1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[7]: https://nodejs.org/api/buffer.html
+
+[8]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number

docs/api-resize.md

@@ -1,15 +1,5 @@
 <!-- Generated by documentation.js. Update this documentation by updating the source code. -->
 
-### Table of Contents
-
--   [resize](#resize)
--   [crop](#crop)
--   [embed](#embed)
--   [max](#max)
--   [min](#min)
--   [ignoreAspectRatio](#ignoreaspectratio)
--   [withoutEnlargement](#withoutenlargement)
-
 ## resize
 
 Resize image to `width` x `height`.
@@ -17,20 +7,20 @@ By default, the resized image is centre cropped to the exact size specified.
 
 Possible kernels are:
 
--   `nearest`: Use [nearest neighbour interpolation](http://en.wikipedia.org/wiki/Nearest-neighbor_interpolation).
--   `cubic`: Use a [Catmull-Rom spline](https://en.wikipedia.org/wiki/Centripetal_Catmull%E2%80%93Rom_spline).
--   `lanczos2`: Use a [Lanczos kernel](https://en.wikipedia.org/wiki/Lanczos_resampling#Lanczos_kernel) with `a=2`.
+-   `nearest`: Use [nearest neighbour interpolation][1].
+-   `cubic`: Use a [Catmull-Rom spline][2].
+-   `lanczos2`: Use a [Lanczos kernel][3] with `a=2`.
 -   `lanczos3`: Use a Lanczos kernel with `a=3` (the default).
 
-**Parameters**
+### Parameters
 
--   `width` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** pixels wide the resultant image should be. Use `null` or `undefined` to auto-scale the width to match the height.
--   `height` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** pixels high the resultant image should be. Use `null` or `undefined` to auto-scale the height to match the width.
--   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** 
-    -   `options.kernel` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** the kernel to use for image reduction. (optional, default `'lanczos3'`)
-    -   `options.fastShrinkOnLoad` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** take greater advantage of the JPEG and WebP shrink-on-load feature, which can lead to a slight moiré pattern on some images. (optional, default `true`)
+-   `width` **[Number][4]?** pixels wide the resultant image should be. Use `null` or `undefined` to auto-scale the width to match the height.
+-   `height` **[Number][4]?** pixels high the resultant image should be. Use `null` or `undefined` to auto-scale the height to match the width.
+-   `options` **[Object][5]?** 
+    -   `options.kernel` **[String][6]** the kernel to use for image reduction. (optional, default `'lanczos3'`)
+    -   `options.fastShrinkOnLoad` **[Boolean][7]** take greater advantage of the JPEG and WebP shrink-on-load feature, which can lead to a slight moiré pattern on some images. (optional, default `true`)
 
-**Examples**
+### Examples
 
 ```javascript
 sharp(inputBuffer)
@@ -47,7 +37,7 @@ sharp(inputBuffer)
   });
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][8]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -61,14 +51,14 @@ Possible attributes of the optional `sharp.gravity` are `north`, `northeast`, `e
 The experimental strategy-based approach resizes so one dimension is at its target length
 then repeatedly ranks edge regions, discarding the edge with the lowest score based on the selected strategy.
 
--   `entropy`: focus on the region with the highest [Shannon entropy](https://en.wikipedia.org/wiki/Entropy_%28information_theory%29).
+-   `entropy`: focus on the region with the highest [Shannon entropy][9].
 -   `attention`: focus on the region with the highest luminance frequency, colour saturation and presence of skin tones.
 
-**Parameters**
+### Parameters
 
--   `crop` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** A member of `sharp.gravity` to crop to an edge/corner or `sharp.strategy` to crop dynamically. (optional, default `'centre'`)
+-   `crop` **[String][6]** A member of `sharp.gravity` to crop to an edge/corner or `sharp.strategy` to crop dynamically. (optional, default `'centre'`)
 
-**Examples**
+### Examples
 
 ```javascript
 const transformer = sharp()
@@ -82,7 +72,7 @@ const transformer = sharp()
 readableStream.pipe(transformer).pipe(writableStream);
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][8]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -94,11 +84,11 @@ 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.
 
-**Parameters**
+### Parameters
 
--   `embed` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** A member of `sharp.gravity` to embed to an edge/corner. (optional, default `'centre'`)
+-   `embed` **[String][6]** A member of `sharp.gravity` to embed to an edge/corner. (optional, default `'centre'`)
 
-**Examples**
+### Examples
 
 ```javascript
 sharp('input.gif')
@@ -115,7 +105,7 @@ sharp('input.gif')
   });
 ```
 
--   Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
+-   Throws **[Error][8]** Invalid parameters
 
 Returns **Sharp** 
 
@@ -126,7 +116,7 @@ while ensuring its dimensions are less than or equal to the `width` and `height`
 
 Both `width` and `height` must be provided via `resize` otherwise the behaviour will default to `crop`.
 
-**Examples**
+### Examples
 
 ```javascript
 sharp(inputBuffer)
@@ -163,11 +153,30 @@ Returns **Sharp**
 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_".
+Use with `max()` to preserve the image's aspect ratio.
 
 The default behaviour _before_ function call is `false`, meaning the image will be enlarged.
 
-**Parameters**
+### Parameters
 
--   `withoutEnlargement` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `true`)
+-   `withoutEnlargement` **[Boolean][7]**  (optional, default `true`)
 
 Returns **Sharp** 
+
+[1]: http://en.wikipedia.org/wiki/Nearest-neighbor_interpolation
+
+[2]: https://en.wikipedia.org/wiki/Centripetal_Catmull%E2%80%93Rom_spline
+
+[3]: https://en.wikipedia.org/wiki/Lanczos_resampling#Lanczos_kernel
+
+[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
+
+[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
+
+[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[8]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
+
+[9]: https://en.wikipedia.org/wiki/Entropy_%28information_theory%29

docs/api-utility.md

@@ -1,12 +1,5 @@
 <!-- Generated by documentation.js. Update this documentation by updating the source code. -->
 
-### Table of Contents
-
--   [cache](#cache)
--   [concurrency](#concurrency)
--   [counters](#counters)
--   [simd](#simd)
-
 ## cache
 
 Gets or, when options are provided, sets the limits of _libvips'_ operation cache.
@@ -14,14 +7,14 @@ Existing entries in the cache will be trimmed after any change in limits.
 This method always returns cache statistics,
 useful for determining how much working memory is required for a particular task.
 
-**Parameters**
+### Parameters
 
--   `options` **([Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object) \| [Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean))** Object with the following attributes, or Boolean where true uses default cache settings and false removes all caching (optional, default `true`)
-    -   `options.memory` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** is the maximum memory in MB to use for this cache (optional, default `50`)
-    -   `options.files` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** is the maximum number of files to hold open (optional, default `20`)
-    -   `options.items` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** is the maximum number of operations to cache (optional, default `100`)
+-   `options` **([Object][1] \| [Boolean][2])** Object with the following attributes, or Boolean where true uses default cache settings and false removes all caching (optional, default `true`)
+    -   `options.memory` **[Number][3]** is the maximum memory in MB to use for this cache (optional, default `50`)
+    -   `options.files` **[Number][3]** is the maximum number of files to hold open (optional, default `20`)
+    -   `options.items` **[Number][3]** is the maximum number of operations to cache (optional, default `100`)
 
-**Examples**
+### Examples
 
 ```javascript
 const stats = sharp.cache();
@@ -33,7 +26,7 @@ sharp.cache( { files: 0 } );
 sharp.cache(false);
 ```
 
-Returns **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** 
+Returns **[Object][1]** 
 
 ## concurrency
 
@@ -47,11 +40,11 @@ is limited by libuv's `UV_THREADPOOL_SIZE` environment variable.
 
 This method always returns the current concurrency.
 
-**Parameters**
+### Parameters
 
--   `concurrency` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** 
+-   `concurrency` **[Number][3]?** 
 
-**Examples**
+### Examples
 
 ```javascript
 const threads = sharp.concurrency(); // 4
@@ -59,7 +52,7 @@ sharp.concurrency(2); // 2
 sharp.concurrency(0); // 4
 ```
 
-Returns **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** concurrency
+Returns **[Number][3]** concurrency
 
 ## counters
 
@@ -68,13 +61,13 @@ Provides access to internal task counters.
 -   queue is the number of tasks this module has queued waiting for _libuv_ to provide a worker thread from its pool.
 -   process is the number of resize tasks currently being processed.
 
-**Examples**
+### Examples
 
 ```javascript
 const counters = sharp.counters(); // { queue: 2, process: 4 }
 ```
 
-Returns **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** 
+Returns **[Object][1]** 
 
 ## simd
 
@@ -87,11 +80,11 @@ by taking advantage of the SIMD vector unit of the CPU, e.g. Intel SSE and ARM N
 This feature is currently off by default but future versions may reverse this.
 Versions of liborc prior to 0.4.25 are known to segfault under heavy load.
 
-**Parameters**
+### Parameters
 
--   `simd` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)**  (optional, default `false`)
+-   `simd` **[Boolean][2]**  (optional, default `false`)
 
-**Examples**
+### Examples
 
 ```javascript
 const simd = sharp.simd();
@@ -103,4 +96,10 @@ const simd = sharp.simd(true);
 // attempts to enable the use of SIMD, returning true if available
 ```
 
-Returns **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** 
+Returns **[Boolean][2]** 
+
+[1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
+
+[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+
+[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number

docs/changelog.md

@@ -1,9 +1,121 @@
 # Changelog
 
+### v0.20 - "*prebuild*"
+
+Requires libvips v8.6.1.
+
+#### v0.20.7 - 21<sup>st</sup> August 2018
+
+* Use copy+unlink if rename operation fails during installation.
+  [#1345](https://github.com/lovell/sharp/issues/1345)
+
+#### v0.20.6 - 20<sup>th</sup> August 2018
+
+* Add removeAlpha operation to remove alpha channel, if any.
+  [#1248](https://github.com/lovell/sharp/issues/1248)
+
+* Expose mozjpeg quant_table flag.
+  [#1285](https://github.com/lovell/sharp/pull/1285)
+  [@rexxars](https://github.com/rexxars)
+
+* Allow full WebP alphaQuality range of 0-100.
+  [#1290](https://github.com/lovell/sharp/pull/1290)
+  [@sylvaindumont](https://github.com/sylvaindumont)
+
+* Cache libvips binaries to reduce re-install time.
+  [#1301](https://github.com/lovell/sharp/issues/1301)
+
+* Ensure vendor platform mismatch throws error at install time.
+  [#1303](https://github.com/lovell/sharp/issues/1303)
+
+* Improve install time error messages for FreeBSD users.
+  [#1310](https://github.com/lovell/sharp/issues/1310)
+
+* Ensure extractChannel works with 16-bit images.
+  [#1330](https://github.com/lovell/sharp/issues/1330)
+
+* Expose depth option for tile-based output.
+  [#1342](https://github.com/lovell/sharp/pull/1342)
+  [@alundavies](https://github.com/alundavies)
+
+* Add experimental entropy field to stats response.
+
+#### v0.20.5 - 27<sup>th</sup> June 2018
+
+* Expose libjpeg optimize_coding flag.
+  [#1265](https://github.com/lovell/sharp/pull/1265)
+  [@tomlokhorst](https://github.com/tomlokhorst)
+
+#### v0.20.4 - 20<sup>th</sup> June 2018
+
+* Prevent possible rounding error when using shrink-on-load and 90/270 degree rotation.
+  [#1241](https://github.com/lovell/sharp/issues/1241)
+  [@anahit42](https://github.com/anahit42)
+
+* Ensure extractChannel sets correct single-channel colour space interpretation.
+  [#1257](https://github.com/lovell/sharp/issues/1257)
+  [@jeremychone](https://github.com/jeremychone)
+
+#### v0.20.3 - 29<sup>th</sup> May 2018
+
+* Fix tint operation by ensuring LAB interpretation and allowing negative values.
+  [#1235](https://github.com/lovell/sharp/issues/1235)
+  [@wezside](https://github.com/wezside)
+
+#### v0.20.2 - 28<sup>th</sup> April 2018
+
+* Add tint operation to set image chroma.
+  [#825](https://github.com/lovell/sharp/pull/825)
+  [@rikh42](https://github.com/rikh42)
+
+* Add environment variable to ignore globally-installed libvips.
+  [#1165](https://github.com/lovell/sharp/pull/1165)
+  [@oncletom](https://github.com/oncletom)
+
+* Add support for page selection with multi-page input (GIF/TIFF).
+  [#1204](https://github.com/lovell/sharp/pull/1204)
+  [@woolite64](https://github.com/woolite64)
+
+* Add support for Group4 (CCITTFAX4) compression with TIFF output.
+  [#1208](https://github.com/lovell/sharp/pull/1208)
+  [@woolite64](https://github.com/woolite64)
+
+#### v0.20.1 - 17<sup>th</sup> March 2018
+
+* Improve installation experience when a globally-installed libvips below the minimum required version is found.
+  [#1148](https://github.com/lovell/sharp/issues/1148)
+
+* Prevent smartcrop error when cumulative rounding is below target size.
+  [#1154](https://github.com/lovell/sharp/issues/1154)
+  [@ralrom](https://github.com/ralrom)
+
+* Expose libvips' median filter operation.
+  [#1161](https://github.com/lovell/sharp/pull/1161)
+  [@BiancoA](https://github.com/BiancoA)
+
+#### v0.20.0 - 5<sup>th</sup> March 2018
+
+* Add support for prebuilt sharp binaries on common platforms.
+  [#186](https://github.com/lovell/sharp/issues/186)
+
 ### v0.19 - "*suit*"
 
 Requires libvips v8.6.1.
 
+#### v0.19.1 - 24<sup>th</sup> February 2018
+
+* Expose libvips' linear transform feature.
+  [#1024](https://github.com/lovell/sharp/pull/1024)
+  [@3epnm](https://github.com/3epnm)
+
+* Expose angle option for tile-based output.
+  [#1121](https://github.com/lovell/sharp/pull/1121)
+  [@BiancoA](https://github.com/BiancoA)
+
+* Prevent crop operation when image already at or below target dimensions.
+  [#1134](https://github.com/lovell/sharp/issues/1134)
+  [@pieh](https://github.com/pieh)
+
 #### v0.19.0 - 11<sup>th</sup> January 2018
 
 * Expose offset coordinates of strategy-based crop.

docs/css/extra.css

@@ -0,0 +1,5 @@
+/* Nest document subheadings in navigation */
+ul.subnav ul:not(.subnav) {
+  padding-left: 2em;
+  font-size: 80%;
+}

docs/index.md

@@ -13,8 +13,9 @@ Lanczos resampling ensures quality is not sacrificed for speed.
 As well as image resizing, operations such as
 rotation, extraction, compositing and gamma correction are available.
 
-OS X, Windows (x64), Linux (x64, ARM) systems do not require
-the installation of any external runtime dependencies.
+Most 64-bit OS X, Windows and Linux (glibc) systems running
+Node versions 4, 6, 8 and 10
+do not require any additional install or runtime dependencies.
 
 [![Test Coverage](https://coveralls.io/repos/lovell/sharp/badge.png?branch=master)](https://coveralls.io/r/lovell/sharp?branch=master)
 
@@ -46,7 +47,7 @@ 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.
+no child processes are spawned and Promises/async/await are supported.
 
 ### Optimal
 
@@ -105,6 +106,16 @@ the help and code contributions of the following people:
 * [Matthew McEachen](https://github.com/mceachen)
 * [Jarda Kotěšovec](https://github.com/jardakotesovec)
 * [Kenric D'Souza](https://github.com/AzureByte)
+* [Oleh Aleinyk](https://github.com/oaleynik)
+* [Marcel Bretschneider](https://github.com/3epnm)
+* [Andrea Bianco](https://github.com/BiancoA)
+* [Rik Heywood](https://github.com/rikh42)
+* [Thomas Parisot](https://github.com/oncletom)
+* [Nathan Graves](https://github.com/woolite64)
+* [Tom Lokhorst](https://github.com/tomlokhorst)
+* [Espen Hovlandsdal](https://github.com/rexxars)
+* [Sylvain Dumont](https://github.com/sylvaindumont)
+* [Alun Davies](https://github.com/alundavies)
 
 Thank you!
 

docs/install.md

@@ -8,12 +8,29 @@ npm install sharp
 yarn add sharp
 ```
 
-### Prerequisites
+## Prerequisites
 
 * Node v4.5.0+
+
+### Building from source
+
+Pre-compiled binaries for sharp are provided for use with
+Node versions 4, 6, 8 and 10 on
+64-bit Windows, OS X and Linux platforms.
+
+Sharp will be built from source at install time when:
+
+* a globally-installed libvips is detected,
+* pre-compiled binaries do not exist for the current platform and Node version, or
+* when the `npm install --build-from-source` flag is used.
+
+Building from source requires:
+
 * C++11 compatible compiler such as gcc 4.8+, clang 3.0+ or MSVC 2013+
 * [node-gyp](https://github.com/TooTallNate/node-gyp#installation) and its dependencies (includes Python)
 
+## libvips
+
 ### Linux
 
 [![Ubuntu 16.04 Build Status](https://travis-ci.org/lovell/sharp.png?branch=master)](https://travis-ci.org/lovell/sharp)
@@ -23,21 +40,21 @@ This involves an automated HTTPS download of approximately 7MB.
 
 Most recent Linux-based operating systems with glibc running on x64 and ARMv6+ CPUs should "just work", e.g.:
 
-* Debian 7, 8
-* Ubuntu 14.04, 16.04
-* Centos 7
+* Debian 7+
+* Ubuntu 14.04+
+* Centos 7+
 * Fedora
-* openSUSE 13.2
+* openSUSE 13.2+
 * Archlinux
 * Raspbian Jessie
-* Amazon Linux 2017.03.1
+* Amazon Linux
 * Solus
 
 To use a globally-installed version of libvips instead of the provided binaries,
 make sure it is at least the version listed under `config.libvips` in the `package.json` file
 and that it can be located using `pkg-config --modversion vips-cpp`.
 
-If you are using non-stadard paths (anything other than `/usr` or `/usr/local`),
+If you are using non-standard paths (anything other than `/usr` or `/usr/local`),
 you might need to set `PKG_CONFIG_PATH` during `npm install`
 and `LD_LIBRARY_PATH` at runtime.
 
@@ -63,7 +80,7 @@ via `sharp.cache(false)` to avoid a stack overflow.
 
 ### Mac OS
 
-[![OS X 10.9.5 Build Status](https://travis-ci.org/lovell/sharp.png?branch=master)](https://travis-ci.org/lovell/sharp)
+[![OS X 10.12 Build Status](https://travis-ci.org/lovell/sharp.png?branch=master)](https://travis-ci.org/lovell/sharp)
 
 libvips and its dependencies are fetched and stored within `node_modules/sharp/vendor` during `npm install`.
 This involves an automated HTTPS download of approximately 7MB.
@@ -144,6 +161,18 @@ Set the Lambda runtime to Node.js 6.10.
 
 To get the best performance select the largest memory available. A 1536 MB function provides ~12x more CPU time than a 128 MB function.
 
+### NW.js
+
+Run the `nw-gyp` tool after installation.
+
+```sh
+cd node-modules/sharp
+nw-gyp rebuild --arch=x64 --target=[your nw version]
+node node_modules/sharp/install/dll-copy
+```
+
+See also http://docs.nwjs.io/en/latest/For%20Users/Advanced/Use%20Native%20Node%20Modules/
+
 ### Build tools
 
 * [gulp-responsive](https://www.npmjs.com/package/gulp-responsive)
@@ -194,10 +223,17 @@ to the directory containing the `policy.xml` file.
 
 ### Pre-compiled libvips binaries
 
-If a global installation of libvips that meets the
-minimum version requirement cannot be found,
-this module will attempt to download a pre-compiled bundle of libvips
-and its dependencies on Linux and Windows machines.
+This module will attempt to download a pre-compiled bundle of libvips
+and its dependencies on Linux and Windows machines under either of these
+conditions:
+
+1. If a global installation of libvips that meets the
+minimum version requirement cannot be found;
+1. If `SHARP_IGNORE_GLOBAL_LIBVIPS` environment variable is set.
+
+```sh
+SHARP_IGNORE_GLOBAL_LIBVIPS=1 npm install sharp
+```
 
 Should you need to manually download and inspect these files,
 you can do so via https://github.com/lovell/sharp-libvips/releases

install/dll-copy.js

@@ -0,0 +1,34 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+const copyFileSync = require('fs-copy-file-sync');
+const npmLog = require('npmlog');
+
+if (process.platform === 'win32') {
+  const buildDir = path.join(__dirname, '..', 'build');
+  const buildReleaseDir = path.join(buildDir, 'Release');
+  npmLog.info('sharp', `Creating ${buildReleaseDir}`);
+  try {
+    fs.mkdirSync(buildDir);
+    fs.mkdirSync(buildReleaseDir);
+  } catch (err) {}
+  const vendorLibDir = path.join(__dirname, '..', 'vendor', 'lib');
+  npmLog.info('sharp', `Copying DLLs from ${vendorLibDir} to ${buildReleaseDir}`);
+  try {
+    fs
+      .readdirSync(vendorLibDir)
+      .filter(function (filename) {
+        return /\.dll$/.test(filename);
+      })
+      .forEach(function (filename) {
+        copyFileSync(
+          path.join(vendorLibDir, filename),
+          path.join(buildReleaseDir, filename)
+        );
+      });
+  } catch (err) {
+    npmLog.error('sharp', err.message);
+  }
+}

install/libvips.js

@@ -0,0 +1,102 @@
+'use strict';
+
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+
+const detectLibc = require('detect-libc');
+const npmLog = require('npmlog');
+const semver = require('semver');
+const simpleGet = require('simple-get');
+const tar = require('tar');
+const copyFileSync = require('fs-copy-file-sync');
+
+const agent = require('../lib/agent');
+const libvips = require('../lib/libvips');
+const platform = require('../lib/platform');
+
+const minimumLibvipsVersion = libvips.minimumLibvipsVersion;
+const distBaseUrl = process.env.SHARP_DIST_BASE_URL || `https://github.com/lovell/sharp-libvips/releases/download/v${minimumLibvipsVersion}/`;
+
+const extractTarball = function (tarPath) {
+  const vendorPath = path.join(__dirname, '..', 'vendor');
+  if (!fs.existsSync(vendorPath)) {
+    fs.mkdirSync(vendorPath);
+  }
+  tar
+    .extract({
+      file: tarPath,
+      cwd: vendorPath,
+      strict: true
+    })
+    .catch(function (err) {
+      throw err;
+    });
+};
+
+try {
+  const useGlobalLibvips = libvips.useGlobalLibvips();
+  if (useGlobalLibvips) {
+    const globalLibvipsVersion = libvips.globalLibvipsVersion();
+    npmLog.info('sharp', `Detected globally-installed libvips v${globalLibvipsVersion}`);
+    npmLog.info('sharp', 'Building from source via node-gyp');
+    process.exit(1);
+  } else if (libvips.hasVendoredLibvips()) {
+    npmLog.info('sharp', `Using existing vendored libvips v${minimumLibvipsVersion}`);
+  } else {
+    // Is this arch/platform supported?
+    const arch = process.env.npm_config_arch || process.arch;
+    const platformAndArch = platform();
+    if (platformAndArch === 'win32-ia32') {
+      throw new Error('Windows x86 (32-bit) node.exe is not supported');
+    }
+    if (arch === 'ia32') {
+      throw new Error(`Intel Architecture 32-bit systems require manual installation of libvips >= ${minimumLibvipsVersion}`);
+    }
+    if (platformAndArch === 'freebsd-x64') {
+      throw new Error(`FreeBSD systems require manual installation of libvips >= ${minimumLibvipsVersion}`);
+    }
+    if (detectLibc.isNonGlibcLinux) {
+      throw new Error(`Use with ${detectLibc.family} libc requires manual installation of libvips >= ${minimumLibvipsVersion}`);
+    }
+    if (detectLibc.family === detectLibc.GLIBC && detectLibc.version && semver.lt(`${detectLibc.version}.0`, '2.13.0')) {
+      throw new Error(`Use with glibc version ${detectLibc.version} requires manual installation of libvips >= ${minimumLibvipsVersion}`);
+    }
+    // Download to per-process temporary file
+    const tarFilename = ['libvips', minimumLibvipsVersion, platformAndArch].join('-') + '.tar.gz';
+    const tarPathCache = path.join(libvips.cachePath(), tarFilename);
+    if (fs.existsSync(tarPathCache)) {
+      npmLog.info('sharp', `Using cached ${tarPathCache}`);
+      extractTarball(tarPathCache);
+    } else {
+      const tarPathTemp = path.join(os.tmpdir(), `${process.pid}-${tarFilename}`);
+      const tmpFile = fs.createWriteStream(tarPathTemp);
+      const url = distBaseUrl + tarFilename;
+      npmLog.info('sharp', `Downloading ${url}`);
+      simpleGet({ url: url, agent: agent() }, function (err, response) {
+        if (err) {
+          throw err;
+        }
+        if (response.statusCode !== 200) {
+          throw new Error(`Status ${response.statusCode}`);
+        }
+        response.pipe(tmpFile);
+      });
+      tmpFile.on('close', function () {
+        try {
+          // Attempt to rename
+          fs.renameSync(tarPathTemp, tarPathCache);
+        } catch (err) {
+          // Fall back to copy and unlink
+          copyFileSync(tarPathTemp, tarPathCache);
+          fs.unlinkSync(tarPathTemp);
+        }
+        extractTarball(tarPathCache);
+      });
+    }
+  }
+} catch (err) {
+  npmLog.error('sharp', err.message);
+  npmLog.error('sharp', 'Please see http://sharp.pixelplumbing.com/page/install');
+  process.exit(1);
+}

lib/channel.js

@@ -12,6 +12,23 @@ const bool = {
   eor: 'eor'
 };
 
+/**
+ * Remove alpha channel, if any. This is a no-op if the image does not have an alpha channel.
+ *
+ * @example
+ * sharp('rgba.png')
+ *   .removeAlpha()
+ *   .toFile('rgb.png', function(err, info) {
+ *     // rgb.png is a 3 channel image without an alpha channel
+ *   });
+ *
+ * @returns {Sharp}
+ */
+function removeAlpha () {
+  this.options.removeAlpha = true;
+  return this;
+}
+
 /**
  * Extract a single channel from a multi-channel image.
  *
@@ -102,6 +119,7 @@ function bandbool (boolOp) {
 module.exports = function (Sharp) {
   // Public instance functions
   [
+    removeAlpha,
     extractChannel,
     joinChannel,
     bandbool

lib/colour.js

@@ -38,6 +38,21 @@ function background (rgba) {
   return this;
 }
 
+/**
+ * Tint the image using the provided chroma while preserving the image luminance.
+ * An alpha channel may be present and will be unchanged by the operation.
+ *
+ * @param {String|Object} rgb - parsed by the [color](https://www.npmjs.org/package/color) module to extract chroma values.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameter
+ */
+function tint (rgb) {
+  const colour = color(rgb);
+  this.options.tintA = colour.a();
+  this.options.tintB = colour.b();
+  return this;
+}
+
 /**
  * Convert to 8-bit greyscale; 256 shades of grey.
  * This is a linear operation. If the input image is in a non-linear colour space such as sRGB, use `gamma()` with `greyscale()` for the best results.
@@ -95,6 +110,7 @@ module.exports = function (Sharp) {
   // Public instance functions
   [
     background,
+    tint,
     greyscale,
     grayscale,
     toColourspace,

lib/composite.js

@@ -19,8 +19,7 @@ const is = require('./is');
  *   .overlayWith('overlay.png', { gravity: sharp.gravity.southeast } )
  *   .sharpen()
  *   .withMetadata()
- *   .quality(90)
- *   .webp()
+ *   .webp( { quality: 90 } )
  *   .toBuffer()
  *   .then(function(outputBuffer) {
  *     // outputBuffer contains upside down, 300px wide, alpha channel flattened

lib/constructor.js

@@ -81,7 +81,7 @@ const debuglog = util.debuglog('sharp');
  *     width: 300,
  *     height: 200,
  *     channels: 4,
- *     background: { r: 255, g: 0, b: 0, alpha: 128 }
+ *     background: { r: 255, g: 0, b: 0, alpha: 0.5 }
  *   }
  * })
  * .png()
@@ -97,6 +97,7 @@ const debuglog = util.debuglog('sharp');
  *  to decode images, even if the data is corrupt or invalid. Set this flag to true
  *  if you'd rather halt processing and raise an error when loading invalid images.
  * @param {Number} [options.density=72] - integral number representing the DPI for vector images.
+ * @param {Number} [options.page=0] - page number to extract for multi-page input (GIF, TIFF)
  * @param {Object} [options.raw] - describes raw pixel input image data. See `raw()` for pixel ordering.
  * @param {Number} [options.raw.width]
  * @param {Number} [options.raw.height]
@@ -151,8 +152,11 @@ const Sharp = function (input, options) {
     fastShrinkOnLoad: true,
     // operations
     background: [0, 0, 0, 255],
+    tintA: 128,
+    tintB: 128,
     flatten: false,
     negate: false,
+    medianSize: 0,
     blurSigma: 0,
     sharpenSigma: 0,
     sharpenFlat: 1,
@@ -167,6 +171,7 @@ const Sharp = function (input, options) {
     booleanFileIn: '',
     joinChannelIn: [],
     extractChannel: -1,
+    removeAlpha: false,
     colourspace: 'srgb',
     // overlay
     overlayGravity: 0,
@@ -188,6 +193,8 @@ const Sharp = function (input, options) {
     jpegTrellisQuantisation: false,
     jpegOvershootDeringing: false,
     jpegOptimiseScans: false,
+    jpegOptimiseCoding: true,
+    jpegQuantisationTable: 0,
     pngProgressive: false,
     pngCompressionLevel: 9,
     pngAdaptiveFiltering: false,
@@ -203,6 +210,8 @@ const Sharp = function (input, options) {
     tiffYres: 1.0,
     tileSize: 256,
     tileOverlap: 0,
+    linearA: 1,
+    linearB: 0,
     // Function to notify of libvips warnings
     debuglog: debuglog,
     // Function to notify of queue length changes

lib/input.js

@@ -57,6 +57,12 @@ function _createInputDescriptor (input, inputOptions, containerOptions) {
         throw new Error('Expected width, height and channels for raw pixel input');
       }
     }
+    // Page input for multi-page TIFF
+    if (is.defined(inputOptions.page)) {
+      if (is.integer(inputOptions.page) && is.inRange(inputOptions.page, 0, 100000)) {
+        inputDescriptor.page = inputOptions.page;
+      }
+    }
     // Create new image
     if (is.defined(inputOptions.create)) {
       if (
@@ -171,8 +177,8 @@ function clone () {
  * A Promises/A+ promise is returned when `callback` is not provided.
  *
  * - `format`: Name of decoder used to decompress image data e.g. `jpeg`, `png`, `webp`, `gif`, `svg`
- * - `width`: Number of pixels wide
- * - `height`: Number of pixels high
+ * - `width`: Number of pixels wide (EXIF orientation is not taken into consideration)
+ * - `height`: Number of pixels high (EXIF orientation is not taken into consideration)
  * - `space`: Name of colour space interpretation e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...](https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L636)
  * - `channels`: Number of bands e.g. `3` for sRGB, `4` for CMYK
  * - `depth`: Name of pixel depth format e.g. `uchar`, `char`, `ushort`, `float` [...](https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L672)
@@ -258,6 +264,7 @@ function metadata (callback) {
  *     - `maxX` (x-coordinate of one of the pixel where the maximum lies)
  *     - `maxY` (y-coordinate of one of the pixel where the maximum lies)
  * - `isOpaque`: Value to identify if the image is opaque or transparent, based on the presence and use of alpha channel
+ * - `entropy`: Histogram-based estimation of greyscale entropy, discarding alpha channel if any (experimental)
  *
  * @example
  * const image = sharp(inputJpg);

lib/libvips.js

@@ -0,0 +1,82 @@
+'use strict';
+
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+const spawnSync = require('child_process').spawnSync;
+const semver = require('semver');
+const platform = require('./platform');
+
+const env = process.env;
+const minimumLibvipsVersion = env.npm_package_config_libvips || require('../package.json').config.libvips;
+
+const spawnSyncOptions = {
+  encoding: 'utf8',
+  shell: true
+};
+
+const cachePath = function () {
+  const npmCachePath = env.npm_config_cache || (env.APPDATA ? path.join(env.APPDATA, 'npm-cache') : path.join(os.homedir(), '.npm'));
+  if (!fs.existsSync(npmCachePath)) {
+    fs.mkdirSync(npmCachePath);
+  }
+  const libvipsCachePath = path.join(npmCachePath, '_libvips');
+  if (!fs.existsSync(libvipsCachePath)) {
+    fs.mkdirSync(libvipsCachePath);
+  }
+  return libvipsCachePath;
+};
+
+const globalLibvipsVersion = function () {
+  if (process.platform !== 'win32') {
+    const globalLibvipsVersion = spawnSync(`PKG_CONFIG_PATH="${pkgConfigPath()}" pkg-config --modversion vips-cpp`, spawnSyncOptions).stdout || '';
+    return globalLibvipsVersion.trim();
+  } else {
+    return '';
+  }
+};
+
+const hasVendoredLibvips = function () {
+  const currentPlatformId = platform();
+  let vendorPlatformId;
+  try {
+    vendorPlatformId = require(path.join(__dirname, '..', 'vendor', 'platform.json'));
+  } catch (err) {}
+  if (vendorPlatformId) {
+    if (currentPlatformId === vendorPlatformId) {
+      return true;
+    } else {
+      throw new Error(`'${vendorPlatformId}' binaries cannot be used on the '${currentPlatformId}' platform. Please remove the 'node_modules/sharp/vendor' directory and run 'npm install'.`);
+    }
+  }
+  return false;
+};
+
+const pkgConfigPath = function () {
+  if (process.platform !== 'win32') {
+    const brewPkgConfigPath = spawnSync('which brew >/dev/null 2>&1 && eval $(brew --env) && echo $PKG_CONFIG_LIBDIR', spawnSyncOptions).stdout || '';
+    return [brewPkgConfigPath.trim(), env.PKG_CONFIG_PATH, '/usr/local/lib/pkgconfig', '/usr/lib/pkgconfig']
+      .filter(function (p) { return !!p; })
+      .join(':');
+  } else {
+    return '';
+  }
+};
+
+const useGlobalLibvips = function () {
+  if (Boolean(env.SHARP_IGNORE_GLOBAL_LIBVIPS) === true) {
+    return false;
+  }
+
+  const globalVipsVersion = globalLibvipsVersion();
+  return !!globalVipsVersion && semver.gte(globalVipsVersion, minimumLibvipsVersion);
+};
+
+module.exports = {
+  minimumLibvipsVersion: minimumLibvipsVersion,
+  cachePath: cachePath,
+  globalLibvipsVersion: globalLibvipsVersion,
+  hasVendoredLibvips: hasVendoredLibvips,
+  pkgConfigPath: pkgConfigPath,
+  useGlobalLibvips: useGlobalLibvips
+};

lib/operation.js

@@ -156,6 +156,26 @@ function sharpen (sigma, flat, jagged) {
   return this;
 }
 
+/**
+ * Apply median filter.
+ * When used without parameters the default window is 3x3.
+ * @param {Number} [size=3] square mask size: size x size
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function median (size) {
+  if (!is.defined(size)) {
+    // No arguments: default to 3x3
+    this.options.medianSize = 3;
+  } else if (is.integer(size) && is.inRange(size, 1, 1000)) {
+    // Numeric argument: specific sigma
+    this.options.medianSize = size;
+  } else {
+    throw new Error('Invalid median size ' + size);
+  }
+  return this;
+}
+
 /**
  * Blur the image.
  * When used without parameters, performs a fast, mild blur of the output image.
@@ -406,6 +426,33 @@ function boolean (operand, operator, options) {
   return this;
 }
 
+/**
+ * Apply the linear formula a * input + b to the image (levels adjustment)
+ * @param {Number} [a=1.0] multiplier
+ * @param {Number} [b=0.0] offset
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function linear (a, b) {
+  if (!is.defined(a)) {
+    this.options.linearA = 1.0;
+  } else if (is.number(a)) {
+    this.options.linearA = a;
+  } else {
+    throw new Error('Invalid linear transform multiplier ' + a);
+  }
+
+  if (!is.defined(b)) {
+    this.options.linearB = 0.0;
+  } else if (is.number(b)) {
+    this.options.linearB = b;
+  } else {
+    throw new Error('Invalid linear transform offset ' + b);
+  }
+
+  return this;
+}
+
 /**
  * Decorate the Sharp prototype with operation-related functions.
  * @private
@@ -417,6 +464,7 @@ module.exports = function (Sharp) {
     flip,
     flop,
     sharpen,
+    median,
     blur,
     extend,
     flatten,
@@ -427,7 +475,8 @@ module.exports = function (Sharp) {
     normalize,
     convolve,
     threshold,
-    boolean
+    boolean,
+    linear
   ].forEach(function (f) {
     Sharp.prototype[f.name] = f;
   });

lib/output.js

@@ -12,6 +12,16 @@ const sharp = require('../build/Release/sharp.node');
  *
  * A `Promise` is returned when `callback` is not provided.
  *
+ * @example
+ * sharp(input)
+ *   .toFile('output.png', (err, info) => { ... });
+ *
+ * @example
+ * sharp(input)
+ *   .toFile('output.png')
+ *   .then(info => { ... })
+ *   .catch(err => { ... });
+ *
  * @param {String} fileOut - the path to write the image data to.
  * @param {Function} [callback] - called on completion with two arguments `(err, info)`.
  * `info` contains the output image `format`, `size` (bytes), `width`, `height`,
@@ -58,6 +68,22 @@ function toFile (fileOut, callback) {
  *
  * A `Promise` is returned when `callback` is not provided.
  *
+ * @example
+ * sharp(input)
+ *   .toBuffer((err, data, info) => { ... });
+ *
+ * @example
+ * sharp(input)
+ *   .toBuffer()
+ *   .then(data => { ... })
+ *   .catch(err => { ... });
+ *
+ * @example
+ * sharp(input)
+ *   .toBuffer({ resolveWithObject: true })
+ *   .then(({ data, info }) => { ... })
+ *   .catch(err => { ... });
+ *
  * @param {Object} [options]
  * @param {Boolean} [options.resolveWithObject] Resolve the Promise with an Object containing `data` and `info` properties instead of resolving only with `data`.
  * @param {Function} [callback]
@@ -76,6 +102,13 @@ function toBuffer (options, callback) {
  * Include all metadata (EXIF, XMP, IPTC) from the input image in the output image.
  * The default behaviour, when `withMetadata` is not used, is to strip all metadata and convert to the device-independent sRGB colour space.
  * This will also convert to and add a web-friendly sRGB ICC profile.
+ *
+ * @example
+ * sharp('input.jpg')
+ *   .withMetadata()
+ *   .toFile('output-with-metadata.jpg')
+ *   .then(info => { ... });
+ *
  * @param {Object} [withMetadata]
  * @param {Number} [withMetadata.orientation] value between 1 and 8, used to update the EXIF `Orientation` tag.
  * @returns {Sharp}
@@ -97,6 +130,16 @@ function withMetadata (withMetadata) {
 
 /**
  * Use these JPEG options for output image.
+ *
+ * @example
+ * // Convert any input to very high quality JPEG output
+ * const data = await sharp(input)
+ *   .jpeg({
+ *     quality: 100,
+ *     chromaSubsampling: '4:4:4'
+ *   })
+ *   .toBuffer();
+ *
  * @param {Object} [options] - output options
  * @param {Number} [options.quality=80] - quality, integer 1-100
  * @param {Boolean} [options.progressive=false] - use progressive (interlace) scan
@@ -105,6 +148,10 @@ function withMetadata (withMetadata) {
  * @param {Boolean} [options.overshootDeringing=false] - apply overshoot deringing, requires mozjpeg
  * @param {Boolean} [options.optimiseScans=false] - optimise progressive scans, forces progressive, requires mozjpeg
  * @param {Boolean} [options.optimizeScans=false] - alternative spelling of optimiseScans
+ * @param {Boolean} [options.optimiseCoding=true] - optimise Huffman coding tables
+ * @param {Boolean} [options.optimizeCoding=true] - alternative spelling of optimiseCoding
+ * @param {Number} [options.quantisationTable=0] - quantization table to use, integer 0-8, requires mozjpeg
+ * @param {Number} [options.quantizationTable=0] - alternative spelling of quantisationTable
  * @param {Boolean} [options.force=true] - force JPEG output, otherwise attempt to use input format
  * @returns {Sharp}
  * @throws {Error} Invalid options
@@ -142,12 +189,34 @@ function jpeg (options) {
         this.options.jpegProgressive = true;
       }
     }
+    options.optimiseCoding = is.bool(options.optimizeCoding) ? options.optimizeCoding : options.optimiseCoding;
+    if (is.defined(options.optimiseCoding)) {
+      this._setBooleanOption('jpegOptimiseCoding', options.optimiseCoding);
+    }
+    options.quantisationTable = is.number(options.quantizationTable) ? options.quantizationTable : options.quantisationTable;
+    if (is.defined(options.quantisationTable)) {
+      if (is.integer(options.quantisationTable) && is.inRange(options.quantisationTable, 0, 8)) {
+        this.options.jpegQuantisationTable = options.quantisationTable;
+      } else {
+        throw new Error('Invalid quantisation table (integer, 0-8) ' + options.quantisationTable);
+      }
+    }
   }
   return this._updateFormatOut('jpeg', options);
 }
 
 /**
  * Use these PNG options for output image.
+ *
+ * PNG output is always full colour at 8 or 16 bits per pixel.
+ * Indexed PNG input at 1, 2 or 4 bits per pixel is converted to 8 bits per pixel.
+ *
+ * @example
+ * // Convert any input to PNG output
+ * const data = await sharp(input)
+ *   .png()
+ *   .toBuffer();
+ *
  * @param {Object} [options]
  * @param {Boolean} [options.progressive=false] - use progressive (interlace) scan
  * @param {Number} [options.compressionLevel=9] - zlib compression level, 0-9
@@ -177,6 +246,13 @@ function png (options) {
 
 /**
  * Use these WebP options for output image.
+ *
+ * @example
+ * // Convert any input to lossless WebP output
+ * const data = await sharp(input)
+ *   .webp({ lossless: true })
+ *   .toBuffer();
+ *
  * @param {Object} [options] - output options
  * @param {Number} [options.quality=80] - quality, integer 1-100
  * @param {Number} [options.alphaQuality=100] - quality of alpha layer, integer 0-100
@@ -195,10 +271,10 @@ function webp (options) {
     }
   }
   if (is.object(options) && is.defined(options.alphaQuality)) {
-    if (is.integer(options.alphaQuality) && is.inRange(options.alphaQuality, 1, 100)) {
+    if (is.integer(options.alphaQuality) && is.inRange(options.alphaQuality, 0, 100)) {
       this.options.webpAlphaQuality = options.alphaQuality;
     } else {
-      throw new Error('Invalid webp alpha quality (integer, 1-100) ' + options.alphaQuality);
+      throw new Error('Invalid webp alpha quality (integer, 0-100) ' + options.alphaQuality);
     }
   }
   if (is.object(options) && is.defined(options.lossless)) {
@@ -212,10 +288,21 @@ function webp (options) {
 
 /**
  * Use these TIFF options for output image.
+ *
+ * @example
+ * // Convert SVG input to LZW-compressed, 1 bit per pixel TIFF output
+ * sharp('input.svg')
+ *   .tiff({
+ *     compression: 'lzw',
+ *     squash: true
+ *   })
+ *   .toFile('1-bpp-output.tiff')
+ *   .then(info => { ... });
+ *
  * @param {Object} [options] - output options
  * @param {Number} [options.quality=80] - quality, integer 1-100
  * @param {Boolean} [options.force=true] - force TIFF output, otherwise attempt to use input format
- * @param {Boolean} [options.compression='jpeg'] - compression options: lzw, deflate, jpeg
+ * @param {Boolean} [options.compression='jpeg'] - compression options: lzw, deflate, jpeg, ccittfax4
  * @param {Boolean} [options.predictor='horizontal'] - compression predictor options: none, horizontal, float
  * @param {Number} [options.xres=1.0] - horizontal resolution in pixels/mm
  * @param {Number} [options.yres=1.0] - vertical resolution in pixels/mm
@@ -255,10 +342,10 @@ function tiff (options) {
   }
   // compression
   if (is.defined(options) && is.defined(options.compression)) {
-    if (is.string(options.compression) && is.inArray(options.compression, ['lzw', 'deflate', 'jpeg', 'none'])) {
+    if (is.string(options.compression) && is.inArray(options.compression, ['lzw', 'deflate', 'jpeg', 'ccittfax4', 'none'])) {
       this.options.tiffCompression = options.compression;
     } else {
-      const message = `Invalid compression option "${options.compression}". Should be one of: lzw, deflate, jpeg, none`;
+      const message = `Invalid compression option "${options.compression}". Should be one of: lzw, deflate, jpeg, ccittfax4, none`;
       throw new Error(message);
     }
   }
@@ -276,6 +363,13 @@ function tiff (options) {
 
 /**
  * Force output to be raw, uncompressed uint8 pixel data.
+ *
+ * @example
+ * // Extract raw RGB pixel data from JPEG input
+ * const { data, info } = await sharp('input.jpg')
+ *   .raw()
+ *   .toBuffer({ resolveWithObject: true });
+ *
  * @returns {Sharp}
  */
 function raw () {
@@ -284,6 +378,13 @@ function raw () {
 
 /**
  * Force output to a given format.
+ *
+ * @example
+ * // Convert any input to PNG output
+ * const data = await sharp(input)
+ *   .toFormat('png')
+ *   .toBuffer();
+ *
  * @param {(String|Object)} format - as a String or an Object with an 'id' attribute
  * @param {Object} options - output options
  * @returns {Sharp}
@@ -305,6 +406,8 @@ function toFormat (format, options) {
  * Set the format and options for tile images via the `toFormat`, `jpeg`, `png` or `webp` functions.
  * Use a `.zip` or `.szi` file extension with `toFile` to write to a compressed archive file format.
  *
+ * Warning: multiple sharp instances concurrently producing tile output can expose a possible race condition in some versions of libgsf.
+ *
  * @example
  *  sharp('input.tiff')
  *   .png()
@@ -319,6 +422,8 @@ function toFormat (format, options) {
  * @param {Object} [tile]
  * @param {Number} [tile.size=256] tile size in pixels, a value between 1 and 8192.
  * @param {Number} [tile.overlap=0] tile overlap in pixels, a value between 0 and 8192.
+ * @param {Number} [tile.angle=0] tile angle of rotation, must be a multiple of 90.
+ * @param {String} [tile.depth] how deep to make the pyramid, possible values are `onepixel`, `onetile` or `one`, default based on layout.
  * @param {String} [tile.container='fs'] tile container, with value `fs` (filesystem) or `zip` (compressed file).
  * @param {String} [tile.layout='dz'] filesystem layout, possible values are `dz`, `zoomify` or `google`.
  * @returns {Sharp}
@@ -361,6 +466,24 @@ function tile (tile) {
         throw new Error('Invalid tile layout ' + tile.layout);
       }
     }
+
+    // Angle of rotation,
+    if (is.defined(tile.angle)) {
+      if (is.integer(tile.angle) && !(tile.angle % 90)) {
+        this.options.tileAngle = tile.angle;
+      } else {
+        throw new Error('Unsupported angle: angle must be a positive/negative multiple of 90 ' + tile.angle);
+      }
+    }
+
+    // Depth of tiles
+    if (is.defined(tile.depth)) {
+      if (is.string(tile.depth) && is.inArray(tile.depth, ['onepixel', 'onetile', 'one'])) {
+        this.options.tileDepth = tile.depth;
+      } else {
+        throw new Error("Invalid tile depth '" + tile.depth + "', should be one of 'onepixel', 'onetile' or 'one'");
+      }
+    }
   }
   // Format
   if (is.inArray(this.options.formatOut, ['jpeg', 'png', 'webp'])) {
@@ -368,6 +491,7 @@ function tile (tile) {
   } else if (this.options.formatOut !== 'input') {
     throw new Error('Invalid tile format ' + this.options.formatOut);
   }
+
   return this._updateFormatOut('dz');
 }
 

lib/resize.js

@@ -253,6 +253,7 @@ function ignoreAspectRatio () {
  * 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*".
+ * Use with `max()` to preserve the image's aspect ratio.
  *
  * The default behaviour *before* function call is `false`, meaning the image will be enlarged.
  *

mkdocs.yml

@@ -5,6 +5,8 @@ site_description: High performance Node.js image processing, the fastest module
 copyright: <a href="https://pixelplumbing.com/">pixelplumbing.com</a>
 google_analytics: ['UA-13034748-12', 'sharp.pixelplumbing.com']
 theme: readthedocs
+extra_css:
+  - css/extra.css
 markdown_extensions:
   - toc:
       permalink: True

package.json

@@ -1,7 +1,7 @@
 {
   "name": "sharp",
   "description": "High performance Node.js image processing, the fastest module to resize JPEG, PNG, WebP and TIFF images",
-  "version": "0.19.0",
+  "version": "0.20.7",
   "author": "Lovell Fuller <npm@lovell.info>",
   "homepage": "https://github.com/lovell/sharp",
   "contributors": [
@@ -39,17 +39,28 @@
     "Guy Maliar <guy@tailorbrands.com>",
     "Nicolas Coden <nicolas@ncoden.fr>",
     "Matt Parrish <matt.r.parrish@gmail.com>",
+    "Marcel Bretschneider <marcel.bretschneider@gmail.com>",
     "Matthew McEachen <matthew+github@mceachen.org>",
     "Jarda Kotěšovec <jarda.kotesovec@gmail.com>",
     "Kenric D'Souza <kenric.dsouza@gmail.com>",
-    "Oleh Aleinyk <oleg.aleynik@gmail.com>"
+    "Oleh Aleinyk <oleg.aleynik@gmail.com>",
+    "Marcel Bretschneider <marcel.bretschneider@gmail.com>",
+    "Andrea Bianco <andrea.bianco@unibas.ch>",
+    "Rik Heywood <rik@rik.org>",
+    "Thomas Parisot <hi@oncletom.io>",
+    "Nathan Graves <nathanrgraves+github@gmail.com>",
+    "Tom Lokhorst <tom@lokhorst.eu>",
+    "Espen Hovlandsdal <espen@hovlandsdal.com>",
+    "Sylvain Dumont <sylvain.dumont35@gmail.com>",
+    "Alun Davies <alun.owain.davies@googlemail.com>"
   ],
   "scripts": {
+    "install": "(node install/libvips && node install/dll-copy && prebuild-install) || (node-gyp rebuild && node install/dll-copy)",
     "clean": "rm -rf node_modules/ build/ vendor/ coverage/ test/fixtures/output.*",
-    "test": "semistandard && cc && nyc --reporter=lcov --branches=99 mocha --slow=5000 --timeout=60000 ./test/unit/*.js",
+    "test": "semistandard && cc && nyc --reporter=lcov --branches=99 mocha --slow=5000 --timeout=60000 ./test/unit/*.js && prebuild-ci",
     "coverage": "./test/coverage/report.sh",
     "test-leak": "./test/leak/leak.sh",
-    "docs": "for m in constructor input resize composite operation colour channel output utility; do documentation build --shallow --format=md lib/$m.js >docs/api-$m.md; done"
+    "docs": "for m in constructor input resize composite operation colour channel output utility; do documentation build --shallow --format=md --markdown-toc=false lib/$m.js >docs/api-$m.md; done"
   },
   "main": "lib/index.js",
   "repository": {
@@ -73,25 +84,30 @@
     "vips"
   ],
   "dependencies": {
-    "color": "^2.0.1",
+    "color": "^3.0.0",
     "detect-libc": "^1.0.3",
-    "nan": "^2.8.0",
-    "semver": "^5.4.1",
-    "simple-get": "^2.7.0",
-    "tar": "^4.2.0",
+    "nan": "^2.10.0",
+    "fs-copy-file-sync": "^1.1.1",
+    "npmlog": "^4.1.2",
+    "prebuild-install": "^4.0.0",
+    "semver": "^5.5.1",
+    "simple-get": "^2.8.1",
+    "tar": "^4.4.6",
     "tunnel-agent": "^0.6.0"
   },
   "devDependencies": {
-    "async": "^2.6.0",
-    "cc": "^1.0.1",
-    "documentation": "^5.3.5",
+    "async": "^2.6.1",
+    "cc": "^1.0.2",
+    "decompress-zip": "^0.3.1",
+    "documentation": "^8.1.1",
     "exif-reader": "^1.0.2",
     "icc": "^1.0.0",
-    "mocha": "^4.1.0",
-    "nyc": "^11.4.1",
+    "mocha": "^5.2.0",
+    "nyc": "^12.0.2",
+    "prebuild": "^7.6.2",
+    "prebuild-ci": "^2.2.3",
     "rimraf": "^2.6.2",
-    "semistandard": "^12.0.0",
-    "unzip": "^0.1.11"
+    "semistandard": "^12.0.1"
   },
   "license": "Apache-2.0",
   "config": {

src/common.cc

@@ -63,6 +63,10 @@ namespace sharp {
       descriptor->rawWidth = AttrTo<uint32_t>(input, "rawWidth");
       descriptor->rawHeight = AttrTo<uint32_t>(input, "rawHeight");
     }
+    // Page input for multi-page TIFF
+    if (HasAttr(input, "page")) {
+      descriptor->page = AttrTo<uint32_t>(input, "page");
+    }
     // Create new image
     if (HasAttr(input, "createChannels")) {
       descriptor->createChannels = AttrTo<uint32_t>(input, "createChannels");
@@ -229,6 +233,9 @@ namespace sharp {
             if (imageType == ImageType::MAGICK) {
               option->set("density", std::to_string(descriptor->density).data());
             }
+            if (imageType == ImageType::TIFF) {
+             option->set("page", descriptor->page);
+            }
             image = VImage::new_from_buffer(descriptor->buffer, descriptor->bufferLength, nullptr, option);
             if (imageType == ImageType::SVG || imageType == ImageType::PDF || imageType == ImageType::MAGICK) {
               SetDensity(image, descriptor->density);
@@ -268,6 +275,9 @@ namespace sharp {
             if (imageType == ImageType::MAGICK) {
               option->set("density", std::to_string(descriptor->density).data());
             }
+            if (imageType == ImageType::TIFF) {
+             option->set("page", descriptor->page);
+            }
             image = VImage::new_from_file(descriptor->file.data(), option);
             if (imageType == ImageType::SVG || imageType == ImageType::PDF || imageType == ImageType::MAGICK) {
               SetDensity(image, descriptor->density);

src/common.h

@@ -53,6 +53,7 @@ namespace sharp {
     int rawChannels;
     int rawWidth;
     int rawHeight;
+    int page;
     int createChannels;
     int createWidth;
     int createHeight;
@@ -66,6 +67,7 @@ namespace sharp {
       rawChannels(0),
       rawWidth(0),
       rawHeight(0),
+      page(0),
       createChannels(0),
       createWidth(0),
       createHeight(0) {

src/metadata.cc

@@ -27,7 +27,8 @@ class MetadataWorker : public Nan::AsyncWorker {
   MetadataWorker(
     Nan::Callback *callback, MetadataBaton *baton, Nan::Callback *debuglog,
     std::vector<v8::Local<v8::Object>> const buffersToPersist) :
-    Nan::AsyncWorker(callback), baton(baton), debuglog(debuglog),
+    Nan::AsyncWorker(callback, "sharp:MetadataWorker"),
+    baton(baton), debuglog(debuglog),
     buffersToPersist(buffersToPersist) {
     // Protect Buffer objects from GC, keyed on index
     std::accumulate(buffersToPersist.begin(), buffersToPersist.end(), 0,
@@ -82,9 +83,9 @@ class MetadataWorker : public Nan::AsyncWorker {
         baton->iccLength = iccLength;
       }
       // IPTC
-      if (image.get_typeof(VIPS_META_IPCT_NAME) == VIPS_TYPE_BLOB) {
+      if (image.get_typeof(VIPS_META_IPTC_NAME) == VIPS_TYPE_BLOB) {
         size_t iptcLength;
-        void const *iptc = image.get_blob(VIPS_META_IPCT_NAME, &iptcLength);
+        void const *iptc = image.get_blob(VIPS_META_IPTC_NAME, &iptcLength);
         baton->iptc = static_cast<char *>(g_malloc(iptcLength));
         memcpy(baton->iptc, iptc, iptcLength);
         baton->iptcLength = iptcLength;
@@ -165,12 +166,12 @@ class MetadataWorker : public Nan::AsyncWorker {
     std::string warning = sharp::VipsWarningPop();
     while (!warning.empty()) {
       v8::Local<v8::Value> message[1] = { New(warning).ToLocalChecked() };
-      debuglog->Call(1, message);
+      debuglog->Call(1, message, async_resource);
       warning = sharp::VipsWarningPop();
     }
 
     // Return to JavaScript
-    callback->Call(2, argv);
+    callback->Call(2, argv, async_resource);
   }
 
  private:

src/operations.cc

@@ -28,6 +28,16 @@ using vips::VError;
 
 namespace sharp {
 
+  /*
+    Removes alpha channel, if any.
+  */
+  VImage RemoveAlpha(VImage image) {
+    if (HasAlpha(image)) {
+      image = image.extract_band(0, VImage::option()->set("n", image.bands() - 1));
+    }
+    return image;
+  }
+
   /*
     Composite overlayImage over image at given position
     Assumes alpha channels are already premultiplied and will be unpremultiplied after
@@ -152,6 +162,33 @@ namespace sharp {
     return dst.bandjoin(mask.cast(dst.format()));
   }
 
+  /*
+   * Tint an image using the specified chroma, preserving the original image luminance
+   */
+  VImage Tint(VImage image, double const a, double const b) {
+    // Get original colourspace
+    VipsInterpretation typeBeforeTint = image.interpretation();
+    if (typeBeforeTint == VIPS_INTERPRETATION_RGB) {
+      typeBeforeTint = VIPS_INTERPRETATION_sRGB;
+    }
+    // Extract luminance
+    VImage luminance = image.colourspace(VIPS_INTERPRETATION_LAB)[0];
+    // Create the tinted version by combining the L from the original and the chroma from the tint
+    std::vector<double> chroma {a, b};
+    VImage tinted = luminance
+      .bandjoin(chroma)
+      .copy(VImage::option()->set("interpretation", VIPS_INTERPRETATION_LAB))
+      .colourspace(typeBeforeTint);
+    // Attach original alpha channel, if any
+    if (HasAlpha(image)) {
+      // Extract original alpha channel
+      VImage alpha = image[image.bands() - 1];
+      // Join alpha channel to normalised image
+      tinted = tinted.bandjoin(alpha);
+    }
+    return tinted;
+  }
+
   /*
    * Stretch luminance to cover full dynamic range.
    */
@@ -196,10 +233,8 @@ namespace sharp {
   VImage Gamma(VImage image, double const exponent) {
     if (HasAlpha(image)) {
       // Separate alpha channel
-      VImage imageWithoutAlpha = image.extract_band(0,
-        VImage::option()->set("n", image.bands() - 1));
       VImage alpha = image[image.bands() - 1];
-      return imageWithoutAlpha.gamma(VImage::option()->set("exponent", exponent)).bandjoin(alpha);
+      return RemoveAlpha(image).gamma(VImage::option()->set("exponent", exponent)).bandjoin(alpha);
     } else {
       return image.gamma(VImage::option()->set("exponent", exponent));
     }
@@ -341,4 +376,16 @@ namespace sharp {
     return image.extract_area(left, top, width, height);
   }
 
+  /*
+   * Calculate (a * in + b)
+   */
+  VImage Linear(VImage image, double const a, double const b) {
+    if (HasAlpha(image)) {
+      // Separate alpha channel
+      VImage alpha = image[image.bands() - 1];
+      return RemoveAlpha(image).linear(a, b).bandjoin(alpha);
+    } else {
+      return image.linear(a, b);
+    }
+  }
 }  // namespace sharp

src/operations.h

@@ -25,6 +25,11 @@ using vips::VImage;
 
 namespace sharp {
 
+  /*
+    Removes alpha channel, if any.
+  */
+  VImage RemoveAlpha(VImage image);
+
   /*
     Alpha composite src over dst with given gravity.
     Assumes alpha channels are already premultiplied and will be unpremultiplied after.
@@ -46,6 +51,11 @@ namespace sharp {
   */
   VImage Cutout(VImage src, VImage dst, const int gravity);
 
+  /*
+   * Tint an image using the specified chroma, preserving the original image luminance
+   */
+  VImage Tint(VImage image, double const a, double const b);
+
   /*
    * Stretch luminance to cover full dynamic range.
    */
@@ -92,6 +102,11 @@ namespace sharp {
   */
   VImage Trim(VImage image, int const tolerance);
 
+  /*
+   * Linear adjustment (a * in + b)
+   */
+  VImage Linear(VImage image, double const a, double const b);
+
 }  // namespace sharp
 
 #endif  // SRC_OPERATIONS_H_

src/pipeline.cc

@@ -35,7 +35,8 @@ class PipelineWorker : public Nan::AsyncWorker {
   PipelineWorker(
     Nan::Callback *callback, PipelineBaton *baton, Nan::Callback *debuglog, Nan::Callback *queueListener,
     std::vector<v8::Local<v8::Object>> const buffersToPersist) :
-    Nan::AsyncWorker(callback), baton(baton), debuglog(debuglog), queueListener(queueListener),
+    Nan::AsyncWorker(callback, "sharp:PipelineWorker"),
+    baton(baton), debuglog(debuglog), queueListener(queueListener),
     buffersToPersist(buffersToPersist) {
     // Protect Buffer objects from GC, keyed on index
     std::accumulate(buffersToPersist.begin(), buffersToPersist.end(), 0,
@@ -280,15 +281,17 @@ class PipelineWorker : public Nan::AsyncWorker {
           }
         }
         // Recalculate integral shrink and double residual
-        int shrunkOnLoadWidth = image.width();
-        int shrunkOnLoadHeight = image.height();
+        int const shrunkOnLoadWidth = image.width();
+        int const shrunkOnLoadHeight = image.height();
         if (!baton->rotateBeforePreExtract &&
           (rotation == VIPS_ANGLE_D90 || rotation == VIPS_ANGLE_D270)) {
-          // Swap input output width and height when rotating by 90 or 270 degrees
-          std::swap(shrunkOnLoadWidth, shrunkOnLoadHeight);
+          // Swap when rotating by 90 or 270 degrees
+          xfactor = static_cast<double>(shrunkOnLoadWidth) / static_cast<double>(targetResizeHeight);
+          yfactor = static_cast<double>(shrunkOnLoadHeight) / static_cast<double>(targetResizeWidth);
+        } else {
+          xfactor = static_cast<double>(shrunkOnLoadWidth) / static_cast<double>(targetResizeWidth);
+          yfactor = static_cast<double>(shrunkOnLoadHeight) / static_cast<double>(targetResizeHeight);
         }
-        xfactor = static_cast<double>(shrunkOnLoadWidth) / static_cast<double>(targetResizeWidth);
-        yfactor = static_cast<double>(shrunkOnLoadHeight) / static_cast<double>(targetResizeHeight);
       }
 
       // Ensure we're using a device-independent colour space
@@ -358,6 +361,8 @@ class PipelineWorker : public Nan::AsyncWorker {
       bool const shouldBlur = baton->blurSigma != 0.0;
       bool const shouldConv = baton->convKernelWidth * baton->convKernelHeight > 0;
       bool const shouldSharpen = baton->sharpenSigma != 0.0;
+      bool const shouldApplyMedian = baton->medianSize > 0;
+
       bool const shouldPremultiplyAlpha = HasAlpha(image) &&
         (shouldResize || shouldBlur || shouldConv || shouldSharpen || shouldOverlayWithAlpha);
 
@@ -378,7 +383,6 @@ class PipelineWorker : public Nan::AsyncWorker {
         ) {
           throw vips::VError("Unknown kernel");
         }
-
         image = image.resize(1.0 / xfactor, VImage::option()
           ->set("vscale", 1.0 / yfactor)
           ->set("kernel", kernel));
@@ -465,7 +469,10 @@ class PipelineWorker : public Nan::AsyncWorker {
             ->set("extend", VIPS_EXTEND_BACKGROUND)
             ->set("background", background));
 
-        } else if (baton->canvas != Canvas::IGNORE_ASPECT) {
+        } else if (
+          baton->canvas != Canvas::IGNORE_ASPECT &&
+          (image.width() > baton->width || image.height() > baton->height)
+        ) {
           // Crop/max/min
           if (baton->crop < 9) {
             // Gravity-based crop
@@ -478,6 +485,12 @@ class PipelineWorker : public Nan::AsyncWorker {
             image = image.extract_area(left, top, width, height);
           } else {
             // Attention-based or Entropy-based crop
+            if (baton->width > image.width()) {
+              baton->width = image.width();
+            }
+            if (baton->height > image.height()) {
+              baton->height = image.height();
+            }
             image = image.tilecache(VImage::option()
               ->set("access", baton->accessMethod)
               ->set("threaded", TRUE));
@@ -534,7 +547,10 @@ class PipelineWorker : public Nan::AsyncWorker {
         image = image.embed(baton->extendLeft, baton->extendTop, baton->width, baton->height,
           VImage::option()->set("extend", VIPS_EXTEND_BACKGROUND)->set("background", background));
       }
-
+      // Median - must happen before blurring, due to the utility of blurring after thresholding
+      if (shouldApplyMedian) {
+        image = image.median(baton->medianSize);
+      }
       // Threshold - must happen before blurring, due to the utility of blurring after thresholding
       if (baton->threshold != 0) {
         image = sharp::Threshold(image, baton->threshold, baton->thresholdGrayscale);
@@ -644,6 +660,11 @@ class PipelineWorker : public Nan::AsyncWorker {
         image = sharp::Gamma(image, baton->gamma);
       }
 
+      // Linear adjustment (a * in + b)
+      if (baton->linearA != 1.0 || baton->linearB != 0.0) {
+        image = sharp::Linear(image, baton->linearA, baton->linearB);
+      }
+
       // Apply normalisation - stretch luminance to cover full dynamic range
       if (baton->normalise) {
         image = sharp::Normalise(image);
@@ -662,14 +683,30 @@ class PipelineWorker : public Nan::AsyncWorker {
         image = sharp::Bandbool(image, baton->bandBoolOp);
       }
 
+      // Tint the image
+      if (baton->tintA < 128.0 || baton->tintB < 128.0) {
+        image = sharp::Tint(image, baton->tintA, baton->tintB);
+      }
+
       // Extract an image channel (aka vips band)
       if (baton->extractChannel > -1) {
         if (baton->extractChannel >= image.bands()) {
           (baton->err).append("Cannot extract channel from image. Too few channels in image.");
           return Error();
         }
-        image = image.extract_band(baton->extractChannel);
+        VipsInterpretation const interpretation = sharp::Is16Bit(image.interpretation())
+          ? VIPS_INTERPRETATION_GREY16
+          : VIPS_INTERPRETATION_B_W;
+        image = image
+          .extract_band(baton->extractChannel)
+          .copy(VImage::option()->set("interpretation", interpretation));
       }
+
+      // Remove alpha channel, if any
+      if (baton->removeAlpha) {
+        image = sharp::RemoveAlpha(image);
+      }
+
       // Convert image to sRGB, if not already
       if (sharp::Is16Bit(image.interpretation())) {
         image = image.cast(VIPS_FORMAT_USHORT);
@@ -705,9 +742,10 @@ class PipelineWorker : public Nan::AsyncWorker {
             ->set("interlace", baton->jpegProgressive)
             ->set("no_subsample", baton->jpegChromaSubsampling == "4:4:4")
             ->set("trellis_quant", baton->jpegTrellisQuantisation)
+            ->set("quant_table", baton->jpegQuantisationTable)
             ->set("overshoot_deringing", baton->jpegOvershootDeringing)
             ->set("optimize_scans", baton->jpegOptimiseScans)
-            ->set("optimize_coding", TRUE)));
+            ->set("optimize_coding", baton->jpegOptimiseCoding)));
           baton->bufferOut = static_cast<char*>(area->data);
           baton->bufferOutLength = area->length;
           area->free_fn = nullptr;
@@ -820,9 +858,10 @@ class PipelineWorker : public Nan::AsyncWorker {
             ->set("interlace", baton->jpegProgressive)
             ->set("no_subsample", baton->jpegChromaSubsampling == "4:4:4")
             ->set("trellis_quant", baton->jpegTrellisQuantisation)
+            ->set("quant_table", baton->jpegQuantisationTable)
             ->set("overshoot_deringing", baton->jpegOvershootDeringing)
             ->set("optimize_scans", baton->jpegOptimiseScans)
-            ->set("optimize_coding", TRUE));
+            ->set("optimize_coding", baton->jpegOptimiseCoding));
           baton->formatOut = "jpeg";
           baton->channels = std::min(baton->channels, 3);
         } else if (baton->formatOut == "png" || (mightMatchInput && isPng) || (willMatchInput &&
@@ -899,20 +938,30 @@ class PipelineWorker : public Nan::AsyncWorker {
               {"interlace", baton->jpegProgressive ? "TRUE" : "FALSE"},
               {"no_subsample", baton->jpegChromaSubsampling == "4:4:4" ? "TRUE": "FALSE"},
               {"trellis_quant", baton->jpegTrellisQuantisation ? "TRUE" : "FALSE"},
+              {"quant_table", std::to_string(baton->jpegQuantisationTable)},
               {"overshoot_deringing", baton->jpegOvershootDeringing ? "TRUE": "FALSE"},
               {"optimize_scans", baton->jpegOptimiseScans ? "TRUE": "FALSE"},
-              {"optimize_coding", "TRUE"}
+              {"optimize_coding", baton->jpegOptimiseCoding ? "TRUE": "FALSE"}
             };
             suffix = AssembleSuffixString(extname, options);
           }
           // Write DZ to file
-          image.dzsave(const_cast<char*>(baton->fileOut.data()), VImage::option()
-            ->set("strip", !baton->withMetadata)
-            ->set("tile_size", baton->tileSize)
-            ->set("overlap", baton->tileOverlap)
-            ->set("container", baton->tileContainer)
-            ->set("layout", baton->tileLayout)
-            ->set("suffix", const_cast<char*>(suffix.data())));
+          vips::VOption *options = VImage::option()
+                                       ->set("strip", !baton->withMetadata)
+                                       ->set("tile_size", baton->tileSize)
+                                       ->set("overlap", baton->tileOverlap)
+                                       ->set("container", baton->tileContainer)
+                                       ->set("layout", baton->tileLayout)
+                                       ->set("suffix", const_cast<char*>(suffix.data()))
+                                       ->set("angle", CalculateAngleRotation(baton->tileAngle));
+
+          // libvips chooses a default depth based on layout. Instead of replicating that logic here by
+          // not passing anything - libvips will handle choice
+          if (baton->tileDepth < VIPS_FOREIGN_DZ_DEPTH_LAST) {
+            options->set("depth", baton->tileDepth);
+          }
+
+          image.dzsave(const_cast<char*>(baton->fileOut.data()), options);
           baton->formatOut = "dz";
         } else if (baton->formatOut == "v" || (mightMatchInput && isV) ||
           (willMatchInput && inputImageType == ImageType::VIPS)) {
@@ -1005,18 +1054,18 @@ class PipelineWorker : public Nan::AsyncWorker {
     std::string warning = sharp::VipsWarningPop();
     while (!warning.empty()) {
       v8::Local<v8::Value> message[1] = { New(warning).ToLocalChecked() };
-      debuglog->Call(1, message);
+      debuglog->Call(1, message, async_resource);
       warning = sharp::VipsWarningPop();
     }
 
     // Decrement processing task counter
     g_atomic_int_dec_and_test(&sharp::counterProcess);
     v8::Local<v8::Value> queueLength[1] = { New<v8::Uint32>(sharp::counterQueue) };
-    queueListener->Call(1, queueLength);
+    queueListener->Call(1, queueLength, async_resource);
     delete queueListener;
 
     // Return to JavaScript
-    callback->Call(3, argv);
+    callback->Call(3, argv, async_resource);
   }
 
  private:
@@ -1146,6 +1195,9 @@ NAN_METHOD(pipeline) {
   for (unsigned int i = 0; i < 4; i++) {
     baton->background[i] = AttrTo<double>(background, i);
   }
+  // Tint chroma
+  baton->tintA = AttrTo<double>(options, "tintA");
+  baton->tintB = AttrTo<double>(options, "tintB");
   // Overlay options
   if (HasAttr(options, "overlay")) {
     baton->overlay = CreateInputDescriptor(AttrAs<v8::Object>(options, "overlay"), buffersToPersist);
@@ -1178,6 +1230,7 @@ NAN_METHOD(pipeline) {
   baton->flatten = AttrTo<bool>(options, "flatten");
   baton->negate = AttrTo<bool>(options, "negate");
   baton->blurSigma = AttrTo<double>(options, "blurSigma");
+  baton->medianSize = AttrTo<uint32_t>(options, "medianSize");
   baton->sharpenSigma = AttrTo<double>(options, "sharpenSigma");
   baton->sharpenFlat = AttrTo<double>(options, "sharpenFlat");
   baton->sharpenJagged = AttrTo<double>(options, "sharpenJagged");
@@ -1185,6 +1238,8 @@ NAN_METHOD(pipeline) {
   baton->thresholdGrayscale = AttrTo<bool>(options, "thresholdGrayscale");
   baton->trimTolerance = AttrTo<int32_t>(options, "trimTolerance");
   baton->gamma = AttrTo<double>(options, "gamma");
+  baton->linearA = AttrTo<double>(options, "linearA");
+  baton->linearB = AttrTo<double>(options, "linearB");
   baton->greyscale = AttrTo<bool>(options, "greyscale");
   baton->normalise = AttrTo<bool>(options, "normalise");
   baton->useExifOrientation = AttrTo<bool>(options, "useExifOrientation");
@@ -1197,6 +1252,7 @@ NAN_METHOD(pipeline) {
   baton->extendLeft = AttrTo<int32_t>(options, "extendLeft");
   baton->extendRight = AttrTo<int32_t>(options, "extendRight");
   baton->extractChannel = AttrTo<int32_t>(options, "extractChannel");
+  baton->removeAlpha = AttrTo<bool>(options, "removeAlpha");
   if (HasAttr(options, "boolean")) {
     baton->boolean = CreateInputDescriptor(AttrAs<v8::Object>(options, "boolean"), buffersToPersist);
     baton->booleanOp = sharp::GetBooleanOperation(AttrAsStr(options, "booleanOp"));
@@ -1231,8 +1287,10 @@ NAN_METHOD(pipeline) {
   baton->jpegProgressive = AttrTo<bool>(options, "jpegProgressive");
   baton->jpegChromaSubsampling = AttrAsStr(options, "jpegChromaSubsampling");
   baton->jpegTrellisQuantisation = AttrTo<bool>(options, "jpegTrellisQuantisation");
+  baton->jpegQuantisationTable = AttrTo<uint32_t>(options, "jpegQuantisationTable");
   baton->jpegOvershootDeringing = AttrTo<bool>(options, "jpegOvershootDeringing");
   baton->jpegOptimiseScans = AttrTo<bool>(options, "jpegOptimiseScans");
+  baton->jpegOptimiseCoding = AttrTo<bool>(options, "jpegOptimiseCoding");
   baton->pngProgressive = AttrTo<bool>(options, "pngProgressive");
   baton->pngCompressionLevel = AttrTo<uint32_t>(options, "pngCompressionLevel");
   baton->pngAdaptiveFiltering = AttrTo<bool>(options, "pngAdaptiveFiltering");
@@ -1256,6 +1314,7 @@ NAN_METHOD(pipeline) {
   baton->tileSize = AttrTo<uint32_t>(options, "tileSize");
   baton->tileOverlap = AttrTo<uint32_t>(options, "tileOverlap");
   std::string tileContainer = AttrAsStr(options, "tileContainer");
+  baton->tileAngle = AttrTo<int32_t>(options, "tileAngle");
   if (tileContainer == "zip") {
     baton->tileContainer = VIPS_FOREIGN_DZ_CONTAINER_ZIP;
   } else {
@@ -1270,6 +1329,17 @@ NAN_METHOD(pipeline) {
     baton->tileLayout = VIPS_FOREIGN_DZ_LAYOUT_DZ;
   }
   baton->tileFormat = AttrAsStr(options, "tileFormat");
+  std::string tileDepth = AttrAsStr(options, "tileDepth");
+  if (tileDepth == "onetile") {
+    baton->tileDepth = VIPS_FOREIGN_DZ_DEPTH_ONETILE;
+  } else if (tileDepth == "one") {
+    baton->tileDepth = VIPS_FOREIGN_DZ_DEPTH_ONE;
+  } else if (tileDepth == "onepixel") {
+    baton->tileDepth = VIPS_FOREIGN_DZ_DEPTH_ONEPIXEL;
+  } else {
+    // signal that we do not want to pass any value to dzSave
+    baton->tileDepth = VIPS_FOREIGN_DZ_DEPTH_LAST;
+  }
   // Force random access for certain operations
   if (baton->accessMethod == VIPS_ACCESS_SEQUENTIAL && (
     baton->trimTolerance != 0 || baton->normalise ||
@@ -1290,5 +1360,6 @@ NAN_METHOD(pipeline) {
   // Increment queued task counter
   g_atomic_int_inc(&sharp::counterQueue);
   v8::Local<v8::Value> queueLength[1] = { Nan::New<v8::Uint32>(sharp::counterQueue) };
-  queueListener->Call(1, queueLength);
+  v8::Local<v8::Object> recv = Nan::New<v8::Object>();
+  Nan::Call(*queueListener, recv, 1, queueLength);
 }

src/pipeline.h

@@ -70,15 +70,20 @@ struct PipelineBaton {
   std::string kernel;
   bool fastShrinkOnLoad;
   double background[4];
+  double tintA;
+  double tintB;
   bool flatten;
   bool negate;
   double blurSigma;
+  int medianSize;
   double sharpenSigma;
   double sharpenFlat;
   double sharpenJagged;
   int threshold;
   bool thresholdGrayscale;
   int trimTolerance;
+  double linearA;
+  double linearB;
   double gamma;
   bool greyscale;
   bool normalise;
@@ -97,8 +102,10 @@ struct PipelineBaton {
   bool jpegProgressive;
   std::string jpegChromaSubsampling;
   bool jpegTrellisQuantisation;
+  int jpegQuantisationTable;
   bool jpegOvershootDeringing;
   bool jpegOptimiseScans;
+  bool jpegOptimiseCoding;
   bool pngProgressive;
   int pngCompressionLevel;
   bool pngAdaptiveFiltering;
@@ -124,12 +131,15 @@ struct PipelineBaton {
   VipsOperationBoolean booleanOp;
   VipsOperationBoolean bandBoolOp;
   int extractChannel;
+  bool removeAlpha;
   VipsInterpretation colourspace;
   int tileSize;
   int tileOverlap;
   VipsForeignDzContainer tileContainer;
   VipsForeignDzLayout tileLayout;
   std::string tileFormat;
+  int tileAngle;
+  VipsForeignDzDepth tileDepth;
 
   PipelineBaton():
     input(nullptr),
@@ -151,15 +161,20 @@ struct PipelineBaton {
     cropOffsetLeft(0),
     cropOffsetTop(0),
     premultiplied(false),
+    tintA(128.0),
+    tintB(128.0),
     flatten(false),
     negate(false),
     blurSigma(0.0),
+    medianSize(0),
     sharpenSigma(0.0),
     sharpenFlat(1.0),
     sharpenJagged(2.0),
     threshold(0),
     thresholdGrayscale(true),
     trimTolerance(0),
+    linearA(1.0),
+    linearB(0.0),
     gamma(0.0),
     greyscale(false),
     normalise(false),
@@ -176,8 +191,10 @@ struct PipelineBaton {
     jpegProgressive(false),
     jpegChromaSubsampling("4:2:0"),
     jpegTrellisQuantisation(false),
+    jpegQuantisationTable(0),
     jpegOvershootDeringing(false),
     jpegOptimiseScans(false),
+    jpegOptimiseCoding(true),
     pngProgressive(false),
     pngCompressionLevel(9),
     pngAdaptiveFiltering(false),
@@ -198,11 +215,14 @@ struct PipelineBaton {
     booleanOp(VIPS_OPERATION_BOOLEAN_LAST),
     bandBoolOp(VIPS_OPERATION_BOOLEAN_LAST),
     extractChannel(-1),
+    removeAlpha(false),
     colourspace(VIPS_INTERPRETATION_LAST),
     tileSize(256),
     tileOverlap(0),
     tileContainer(VIPS_FOREIGN_DZ_CONTAINER_FS),
-    tileLayout(VIPS_FOREIGN_DZ_LAYOUT_DZ) {
+    tileLayout(VIPS_FOREIGN_DZ_LAYOUT_DZ),
+    tileAngle(0),
+    tileDepth(VIPS_FOREIGN_DZ_DEPTH_LAST){
       background[0] = 0.0;
       background[1] = 0.0;
       background[2] = 0.0;

src/stats.cc

@@ -28,7 +28,8 @@ class StatsWorker : public Nan::AsyncWorker {
   StatsWorker(
     Nan::Callback *callback, StatsBaton *baton, Nan::Callback *debuglog,
     std::vector<v8::Local<v8::Object>> const buffersToPersist) :
-    Nan::AsyncWorker(callback), baton(baton), debuglog(debuglog),
+    Nan::AsyncWorker(callback, "sharp:StatsWorker"),
+    baton(baton), debuglog(debuglog),
     buffersToPersist(buffersToPersist) {
     // Protect Buffer objects from GC, keyed on index
     std::accumulate(buffersToPersist.begin(), buffersToPersist.end(), 0,
@@ -58,7 +59,6 @@ class StatsWorker : public Nan::AsyncWorker {
     using sharp::MaximumImageAlpha;
 
     vips::VImage image;
-    vips::VImage stats;
     sharp::ImageType imageType = sharp::ImageType::UNKNOWN;
 
     try {
@@ -68,9 +68,8 @@ class StatsWorker : public Nan::AsyncWorker {
     }
     if (imageType != sharp::ImageType::UNKNOWN) {
       try {
-        stats = image.stats();
-        int bands = image.bands();
-        double const max = MaximumImageAlpha(image.interpretation());
+        vips::VImage stats = image.stats();
+        int const bands = image.bands();
         for (int b = 1; b <= bands; b++) {
           ChannelStats cStats(static_cast<int>(stats.getpoint(STAT_MIN_INDEX, b).front()),
                               static_cast<int>(stats.getpoint(STAT_MAX_INDEX, b).front()),
@@ -82,11 +81,15 @@ class StatsWorker : public Nan::AsyncWorker {
                               static_cast<int>(stats.getpoint(STAT_MAXY_INDEX, b).front()));
           baton->channelStats.push_back(cStats);
         }
-
-        // alpha layer is there and the last band i.e. alpha has its max value greater than 0)
-        if (sharp::HasAlpha(image) && stats.getpoint(STAT_MIN_INDEX, bands).front() != max) {
-          baton->isOpaque = false;
+        // Image is not opaque when alpha layer is present and contains a non-mamixa value
+        if (sharp::HasAlpha(image)) {
+          double const minAlpha = static_cast<double>(stats.getpoint(STAT_MIN_INDEX, bands).front());
+          if (minAlpha != MaximumImageAlpha(image.interpretation())) {
+            baton->isOpaque = false;
+          }
         }
+        // Estimate entropy via histogram of greyscale value frequency
+        baton->entropy = std::abs(image.colourspace(VIPS_INTERPRETATION_B_W)[0].hist_find().hist_entropy());
       } catch (vips::VError const &err) {
         (baton->err).append(err.what());
       }
@@ -129,6 +132,7 @@ class StatsWorker : public Nan::AsyncWorker {
 
       Set(info, New("channels").ToLocalChecked(), channels);
       Set(info, New("isOpaque").ToLocalChecked(), New<v8::Boolean>(baton->isOpaque));
+      Set(info, New("entropy").ToLocalChecked(), New<v8::Number>(baton->entropy));
       argv[1] = info;
     }
 
@@ -145,12 +149,12 @@ class StatsWorker : public Nan::AsyncWorker {
     std::string warning = sharp::VipsWarningPop();
     while (!warning.empty()) {
       v8::Local<v8::Value> message[1] = { New(warning).ToLocalChecked() };
-      debuglog->Call(1, message);
+      debuglog->Call(1, message, async_resource);
       warning = sharp::VipsWarningPop();
     }
 
     // Return to JavaScript
-    callback->Call(2, argv);
+    callback->Call(2, argv, async_resource);
   }
 
  private:

src/stats.h

@@ -51,12 +51,14 @@ struct StatsBaton {
   // Output
   std::vector<ChannelStats> channelStats;
   bool isOpaque;
+  double entropy;
 
   std::string err;
 
   StatsBaton():
     input(nullptr),
-    isOpaque(true)
+    isOpaque(true),
+    entropy(0.0)
     {}
 };
 

test/fixtures/index.js

@@ -69,6 +69,8 @@ module.exports = {
   inputJpgOverlayLayer2: getPath('alpha-layer-2-ink.jpg'),
   inputJpgTruncated: getPath('truncated.jpg'), // head -c 10000 2569067123_aca715a2ee_o.jpg > truncated.jpg
   inputJpgCenteredImage: getPath('centered_image.jpeg'),
+  inputJpgRandom: getPath('random.jpg'), // convert -size 200x200 xc:   +noise Random   random.jpg
+  inputJpgThRandom: getPath('thRandom.jpg'), // convert random.jpg  -channel G -threshold 5% -separate +channel -negate thRandom.jpg
 
   inputPng: getPath('50020484-00001.png'), // http://c.searspartsdirect.com/lis_png/PLDM/50020484-00001.png
   inputPngWithTransparency: getPath('blackbug.png'), // public domain
@@ -87,10 +89,12 @@ module.exports = {
   inputPngTestJoinChannel: getPath('testJoinChannel.png'),
   inputPngTruncated: getPath('truncated.png'), // gm convert 2569067123_aca715a2ee_o.jpg -resize 320x240 saw.png ; head -c 10000 saw.png > truncated.png
   inputPngEmbed: getPath('embedgravitybird.png'), // Released to sharp under a CC BY 4.0
+  inputPngRGBWithAlpha: getPath('2569067123_aca715a2ee_o.png'), // http://www.flickr.com/photos/grizdave/2569067123/ (same as inputJpg)
 
   inputWebP: getPath('4.webp'), // http://www.gstatic.com/webp/gallery/4.webp
   inputWebPWithTransparency: getPath('5_webp_a.webp'), // http://www.gstatic.com/webp/gallery3/5_webp_a.webp
   inputTiff: getPath('G31D.TIF'), // http://www.fileformat.info/format/tiff/sample/e6c9a6e5253348f4aef6d17b534360ab/index.htm
+  inputTiffMultipage: getPath('G31D_MULTI.TIF'), // gm convert G31D.TIF -resize 50% G31D_2.TIF ; tiffcp G31D.TIF G31D_2.TIF G31D_MULTI.TIF
   inputTiffCielab: getPath('cielab-dagams.tiff'), // https://github.com/lovell/sharp/issues/646
   inputTiffUncompressed: getPath('uncompressed_tiff.tiff'), // https://code.google.com/archive/p/imagetestsuite/wikis/TIFFTestSuite.wiki file: 0c84d07e1b22b76f24cccc70d8788e4a.tif
   inputTiff8BitDepth: getPath('8bit_depth.tiff'),

test/unit/alpha.js

@@ -81,35 +81,45 @@ describe('Alpha transparency', function () {
       });
   });
 
-  it('Enlargement with non-nearest neighbor interpolation shouldn’t cause dark edges', function (done) {
+  it('Enlargement with non-nearest neighbor interpolation shouldn’t cause dark edges', function () {
     const base = 'alpha-premultiply-enlargement-2048x1536-paper.png';
     const actual = fixtures.path('output.' + base);
     const expected = fixtures.expected(base);
-    sharp(fixtures.inputPngAlphaPremultiplicationSmall)
+    return sharp(fixtures.inputPngAlphaPremultiplicationSmall)
       .resize(2048, 1536)
-      .toFile(actual, function (err) {
-        if (err) {
-          done(err);
-        } else {
-          fixtures.assertMaxColourDistance(actual, expected, 102);
-          done();
-        }
+      .toFile(actual)
+      .then(function () {
+        fixtures.assertMaxColourDistance(actual, expected, 102);
       });
   });
 
-  it('Reduction with non-nearest neighbor interpolation shouldn’t cause dark edges', function (done) {
+  it('Reduction with non-nearest neighbor interpolation shouldn’t cause dark edges', function () {
     const base = 'alpha-premultiply-reduction-1024x768-paper.png';
     const actual = fixtures.path('output.' + base);
     const expected = fixtures.expected(base);
-    sharp(fixtures.inputPngAlphaPremultiplicationLarge)
+    return sharp(fixtures.inputPngAlphaPremultiplicationLarge)
       .resize(1024, 768)
-      .toFile(actual, function (err) {
-        if (err) {
-          done(err);
-        } else {
-          fixtures.assertMaxColourDistance(actual, expected, 102);
-          done();
-        }
+      .toFile(actual)
+      .then(function () {
+        fixtures.assertMaxColourDistance(actual, expected, 102);
       });
   });
+
+  it('Removes alpha from fixtures with transparency, ignores those without', function () {
+    return Promise.all([
+      fixtures.inputPngWithTransparency,
+      fixtures.inputPngWithTransparency16bit,
+      fixtures.inputWebPWithTransparency,
+      fixtures.inputJpg,
+      fixtures.inputPng,
+      fixtures.inputWebP
+    ].map(function (input) {
+      return sharp(input)
+        .removeAlpha()
+        .toBuffer({ resolveWithObject: true })
+        .then(function (result) {
+          assert.strictEqual(3, result.info.channels);
+        });
+    }));
+  });
 });

test/unit/crop.js

@@ -159,6 +159,24 @@ describe('Crop', function () {
     });
   });
 
+  it('Skip crop when post-resize dimensions are at target', function () {
+    return sharp(fixtures.inputJpg)
+      .resize(1600, 1200)
+      .toBuffer()
+      .then(function (input) {
+        return sharp(input)
+          .resize(1110)
+          .crop(sharp.strategy.attention)
+          .toBuffer({ resolveWithObject: true })
+          .then(function (result) {
+            assert.strictEqual(1110, result.info.width);
+            assert.strictEqual(832, result.info.height);
+            assert.strictEqual(undefined, result.info.cropOffsetLeft);
+            assert.strictEqual(undefined, result.info.cropOffsetTop);
+          });
+      });
+  });
+
   describe('Entropy-based strategy', function () {
     it('JPEG', function (done) {
       sharp(fixtures.inputJpg)

test/unit/extractChannel.js

@@ -54,6 +54,32 @@ describe('Image channel extraction', function () {
       });
   });
 
+  it('With colorspace conversion', function (done) {
+    const output = fixtures.path('output.extract-lch.jpg');
+    sharp(fixtures.inputJpg)
+      .toColourspace('lch')
+      .extractChannel(1)
+      .resize(320, 240)
+      .toFile(output, function (err, info) {
+        if (err) throw err;
+        assert.strictEqual(320, info.width);
+        assert.strictEqual(240, info.height);
+        fixtures.assertMaxColourDistance(output, fixtures.expected('extract-lch.jpg'));
+        done();
+      });
+  });
+
+  it('Alpha from 16-bit PNG', function (done) {
+    const output = fixtures.path('output.extract-alpha-16bit.jpg');
+    sharp(fixtures.inputPngWithTransparency16bit)
+      .extractChannel(3)
+      .toFile(output, function (err, info) {
+        if (err) throw err;
+        fixtures.assertMaxColourDistance(output, fixtures.expected('extract-alpha-16bit.jpg'));
+        done();
+      });
+  });
+
   it('Invalid channel number', function () {
     assert.throws(function () {
       sharp(fixtures.inputJpg)

test/unit/io.js

@@ -389,6 +389,16 @@ describe('Input/output', function () {
     });
   });
 
+  describe('Invalid JPEG quantisation table', function () {
+    [-1, 88.2, 'test'].forEach(function (table) {
+      it(table.toString(), function () {
+        assert.throws(function () {
+          sharp().jpeg({ quantisationTable: table });
+        });
+      });
+    });
+  });
+
   it('Progressive JPEG image', function (done) {
     sharp(fixtures.inputJpg)
       .resize(320, 240)
@@ -528,6 +538,22 @@ describe('Input/output', function () {
       });
   });
 
+  it('TIFF file input with invalid page fails gracefully', function (done) {
+    sharp(fixtures.inputTiffMultipage, { page: 2 })
+      .toBuffer(function (err) {
+        assert.strictEqual(true, !!err);
+        done();
+      });
+  });
+
+  it('TIFF buffer input with invalid page fails gracefully', function (done) {
+    sharp(fs.readFileSync(fixtures.inputTiffMultipage), { page: 2 })
+      .toBuffer(function (err) {
+        assert.strictEqual(true, !!err);
+        done();
+      });
+  });
+
   describe('Output filename with unknown extension', function () {
     it('Match JPEG input', function (done) {
       sharp(fixtures.inputJpg)
@@ -810,6 +836,67 @@ describe('Input/output', function () {
       });
   });
 
+  it('Optimise coding generates smaller output length', function (done) {
+    // First generate with optimize coding enabled (default)
+    sharp(fixtures.inputJpg)
+      .resize(320, 240)
+      .jpeg()
+      .toBuffer(function (err, withOptimiseCoding, withInfo) {
+        if (err) throw err;
+        assert.strictEqual(true, withOptimiseCoding.length > 0);
+        assert.strictEqual(withOptimiseCoding.length, withInfo.size);
+        assert.strictEqual('jpeg', withInfo.format);
+        assert.strictEqual(320, withInfo.width);
+        assert.strictEqual(240, withInfo.height);
+        // Then generate with coding disabled
+        sharp(fixtures.inputJpg)
+          .resize(320, 240)
+          .jpeg({ optimizeCoding: false })
+          .toBuffer(function (err, withoutOptimiseCoding, withoutInfo) {
+            if (err) throw err;
+            assert.strictEqual(true, withoutOptimiseCoding.length > 0);
+            assert.strictEqual(withoutOptimiseCoding.length, withoutInfo.size);
+            assert.strictEqual('jpeg', withoutInfo.format);
+            assert.strictEqual(320, withoutInfo.width);
+            assert.strictEqual(240, withoutInfo.height);
+            // Verify optimised image is of a smaller size
+            assert.strictEqual(true, withOptimiseCoding.length < withoutOptimiseCoding.length);
+            done();
+          });
+      });
+  });
+
+  it('Specifying quantisation table provides different JPEG', function (done) {
+    // First generate with default quantisation table
+    sharp(fixtures.inputJpg)
+      .resize(320, 240)
+      .jpeg({ optimiseCoding: false })
+      .toBuffer(function (err, withDefaultQuantisationTable, withInfo) {
+        if (err) throw err;
+        assert.strictEqual(true, withDefaultQuantisationTable.length > 0);
+        assert.strictEqual(withDefaultQuantisationTable.length, withInfo.size);
+        assert.strictEqual('jpeg', withInfo.format);
+        assert.strictEqual(320, withInfo.width);
+        assert.strictEqual(240, withInfo.height);
+        // Then generate with different quantisation table
+        sharp(fixtures.inputJpg)
+          .resize(320, 240)
+          .jpeg({ optimiseCoding: false, quantisationTable: 3 })
+          .toBuffer(function (err, withQuantTable3, withoutInfo) {
+            if (err) throw err;
+            assert.strictEqual(true, withQuantTable3.length > 0);
+            assert.strictEqual(withQuantTable3.length, withoutInfo.size);
+            assert.strictEqual('jpeg', withoutInfo.format);
+            assert.strictEqual(320, withoutInfo.width);
+            assert.strictEqual(240, withoutInfo.height);
+
+            // Verify image is same (as mozjpeg may not be present) size or less
+            assert.strictEqual(true, withQuantTable3.length <= withDefaultQuantisationTable.length);
+            done();
+          });
+      });
+  });
+
   it('Convert SVG to PNG at default 72DPI', function (done) {
     sharp(fixtures.inputSvg)
       .resize(1024)
@@ -880,6 +967,53 @@ describe('Input/output', function () {
       });
   });
 
+  it('Load multi-page TIFF\'s from file', function (done) {
+    sharp(fixtures.inputTiffMultipage) // defaults to page 0
+      .jpeg()
+      .toBuffer(function (err, defaultData, defaultInfo) {
+        if (err) throw err;
+        assert.strictEqual(true, defaultData.length > 0);
+        assert.strictEqual(defaultData.length, defaultInfo.size);
+        assert.strictEqual('jpeg', defaultInfo.format);
+
+        sharp(fixtures.inputTiffMultipage, { page: 1 }) // 50%-scale copy of page 0
+          .jpeg()
+          .toBuffer(function (err, scaledData, scaledInfo) {
+            if (err) throw err;
+            assert.strictEqual(true, scaledData.length > 0);
+            assert.strictEqual(scaledData.length, scaledInfo.size);
+            assert.strictEqual('jpeg', scaledInfo.format);
+            assert.strictEqual(defaultInfo.width, scaledInfo.width * 2);
+            assert.strictEqual(defaultInfo.height, scaledInfo.height * 2);
+            done();
+          });
+      });
+  });
+
+  it('Load multi-page TIFF\'s from Buffer', function (done) {
+    const inputTiffBuffer = fs.readFileSync(fixtures.inputTiffMultipage);
+    sharp(inputTiffBuffer) // defaults to page 0
+      .jpeg()
+      .toBuffer(function (err, defaultData, defaultInfo) {
+        if (err) throw err;
+        assert.strictEqual(true, defaultData.length > 0);
+        assert.strictEqual(defaultData.length, defaultInfo.size);
+        assert.strictEqual('jpeg', defaultInfo.format);
+
+        sharp(inputTiffBuffer, { page: 1 }) // 50%-scale copy of page 0
+          .jpeg()
+          .toBuffer(function (err, scaledData, scaledInfo) {
+            if (err) throw err;
+            assert.strictEqual(true, scaledData.length > 0);
+            assert.strictEqual(scaledData.length, scaledInfo.size);
+            assert.strictEqual('jpeg', scaledInfo.format);
+            assert.strictEqual(defaultInfo.width, scaledInfo.width * 2);
+            assert.strictEqual(defaultInfo.height, scaledInfo.height * 2);
+            done();
+          });
+      });
+  });
+
   it('Save TIFF to Buffer', function (done) {
     sharp(fixtures.inputTiff)
       .resize(320, 240)
@@ -1020,6 +1154,22 @@ describe('Input/output', function () {
       });
   });
 
+  it('TIFF ccittfax4 compression shrinks b-w test file', function (done) {
+    const startSize = fs.statSync(fixtures.inputTiff).size;
+    sharp(fixtures.inputTiff)
+      .toColourspace('b-w')
+      .tiff({
+        squash: true,
+        compression: 'ccittfax4'
+      })
+      .toFile(fixtures.outputTiff, (err, info) => {
+        if (err) throw err;
+        assert.strictEqual('tiff', info.format);
+        assert(info.size < startSize);
+        fs.unlink(fixtures.outputTiff, done);
+      });
+  });
+
   it('TIFF deflate compression with horizontal predictor shrinks test file', function (done) {
     const startSize = fs.statSync(fixtures.inputTiffUncompressed).size;
     sharp(fixtures.inputTiffUncompressed)

test/unit/libvips.js

@@ -0,0 +1,77 @@
+'use strict';
+
+const assert = require('assert');
+const fs = require('fs');
+const semver = require('semver');
+const libvips = require('../../lib/libvips');
+
+const originalPlatform = process.platform;
+
+const setPlatform = function (platform) {
+  Object.defineProperty(process, 'platform', { value: platform });
+};
+
+const restorePlatform = function () {
+  setPlatform(originalPlatform);
+};
+
+describe('libvips binaries', function () {
+  describe('Windows platform', function () {
+    before(function () { setPlatform('win32'); });
+    after(restorePlatform);
+
+    it('pkgConfigPath returns empty string', function () {
+      assert.strictEqual('', libvips.pkgConfigPath());
+    });
+    it('globalLibvipsVersion returns empty string', function () {
+      assert.strictEqual('', libvips.globalLibvipsVersion());
+    });
+    it('globalLibvipsVersion is always false', function () {
+      assert.strictEqual(false, libvips.useGlobalLibvips());
+    });
+  });
+
+  describe('non-Windows platforms', function () {
+    before(function () { setPlatform('linux'); });
+    after(restorePlatform);
+
+    it('pkgConfigPath returns a string', function () {
+      const pkgConfigPath = libvips.pkgConfigPath();
+      assert.strictEqual('string', typeof pkgConfigPath);
+    });
+    it('globalLibvipsVersion returns a string', function () {
+      const globalLibvipsVersion = libvips.globalLibvipsVersion();
+      assert.strictEqual('string', typeof globalLibvipsVersion);
+    });
+    it('globalLibvipsVersion returns a boolean', function () {
+      const useGlobalLibvips = libvips.useGlobalLibvips();
+      assert.strictEqual('boolean', typeof useGlobalLibvips);
+    });
+  });
+
+  describe('platform agnostic', function () {
+    it('minimumLibvipsVersion returns a valid semver', function () {
+      const minimumLibvipsVersion = libvips.minimumLibvipsVersion;
+      assert.strictEqual('string', typeof minimumLibvipsVersion);
+      assert.notStrictEqual(null, semver.valid(minimumLibvipsVersion));
+    });
+    it('hasVendoredLibvips returns a boolean', function () {
+      const hasVendoredLibvips = libvips.hasVendoredLibvips();
+      assert.strictEqual('boolean', typeof hasVendoredLibvips);
+    });
+    it('useGlobalLibvips can be ignored via an env var', function () {
+      process.env.SHARP_IGNORE_GLOBAL_LIBVIPS = 1;
+
+      const useGlobalLibvips = libvips.useGlobalLibvips();
+      assert.strictEqual(false, useGlobalLibvips);
+
+      delete process.env.SHARP_IGNORE_GLOBAL_LIBVIPS;
+    });
+    it('cachePath returns a valid path ending with _libvips', function () {
+      const cachePath = libvips.cachePath();
+      assert.strictEqual('string', typeof cachePath);
+      assert.strictEqual('_libvips', cachePath.substr(-8));
+      assert.strictEqual(true, fs.existsSync(cachePath));
+    });
+  });
+});

test/unit/linear.js

@@ -0,0 +1,79 @@
+'use strict';
+
+const sharp = require('../../');
+const fixtures = require('../fixtures');
+
+const assert = require('assert');
+
+describe('Linear adjustment', function () {
+  const blackPoint = 70;
+  const whitePoint = 203;
+  const a = 255 / (whitePoint - blackPoint);
+  const b = -blackPoint * a;
+
+  it('applies linear levels adjustment w/o alpha ch', function (done) {
+    sharp(fixtures.inputJpgWithLowContrast)
+      .linear(a, b)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        fixtures.assertSimilar(fixtures.expected('low-contrast-linear.jpg'), data, done);
+      });
+  });
+
+  it('applies slope level adjustment w/o alpha ch', function (done) {
+    sharp(fixtures.inputJpgWithLowContrast)
+      .linear(a)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        fixtures.assertSimilar(fixtures.expected('low-contrast-slope.jpg'), data, done);
+      });
+  });
+
+  it('applies offset level adjustment w/o alpha ch', function (done) {
+    sharp(fixtures.inputJpgWithLowContrast)
+      .linear(null, b)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        fixtures.assertSimilar(fixtures.expected('low-contrast-offset.jpg'), data, done);
+      });
+  });
+
+  it('applies linear levels adjustment w alpha ch', function (done) {
+    sharp(fixtures.inputPngOverlayLayer1)
+      .linear(a, b)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        fixtures.assertSimilar(fixtures.expected('alpha-layer-1-fill-linear.png'), data, done);
+      });
+  });
+
+  it('applies slope level adjustment w alpha ch', function (done) {
+    sharp(fixtures.inputPngOverlayLayer1)
+      .linear(a)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        fixtures.assertSimilar(fixtures.expected('alpha-layer-1-fill-slope.png'), data, done);
+      });
+  });
+
+  it('applies offset level adjustment w alpha ch', function (done) {
+    sharp(fixtures.inputPngOverlayLayer1)
+      .linear(null, b)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        fixtures.assertSimilar(fixtures.expected('alpha-layer-1-fill-offset.png'), data, done);
+      });
+  });
+
+  it('Invalid linear arguments', function () {
+    assert.throws(function () {
+      sharp(fixtures.inputPngOverlayLayer1)
+        .linear('foo');
+    });
+
+    assert.throws(function () {
+      sharp(fixtures.inputPngOverlayLayer1)
+        .linear(undefined, { 'bar': 'baz' });
+    });
+  });
+});

test/unit/median.js

@@ -0,0 +1,72 @@
+'use strict';
+
+const assert = require('assert');
+
+const sharp = require('../../');
+const fixtures = require('../fixtures');
+
+describe('Median filter', function () {
+  it('1x1 window', function (done) {
+    sharp(fixtures.inputJpgThRandom)
+      .median(1)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(200, info.width);
+        assert.strictEqual(200, info.height);
+        fixtures.assertSimilar(fixtures.expected('median_1.jpg'), data, done);
+      });
+  });
+
+  it('3x3 window', function (done) {
+    sharp(fixtures.inputJpgThRandom)
+      .median(3)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(200, info.width);
+        assert.strictEqual(200, info.height);
+        fixtures.assertSimilar(fixtures.expected('median_3.jpg'), data, done);
+      });
+  });
+  it('5x5 window', function (done) {
+    sharp(fixtures.inputJpgThRandom)
+      .median(5)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(200, info.width);
+        assert.strictEqual(200, info.height);
+        fixtures.assertSimilar(fixtures.expected('median_5.jpg'), data, done);
+      });
+  });
+
+  it('color image', function (done) {
+    sharp(fixtures.inputJpgRandom)
+      .median(5)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(200, info.width);
+        assert.strictEqual(200, info.height);
+        fixtures.assertSimilar(fixtures.expected('median_color.jpg'), data, done);
+      });
+  });
+
+  it('no windows size', function (done) {
+    sharp(fixtures.inputJpgThRandom)
+      .median()
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(200, info.width);
+        assert.strictEqual(200, info.height);
+        fixtures.assertSimilar(fixtures.expected('median_3.jpg'), data, done);
+      });
+  });
+  it('invalid radius', function () {
+    assert.throws(function () {
+      sharp(fixtures.inputJpg).median(0.1);
+    });
+  });
+});

test/unit/resize.js

@@ -130,6 +130,25 @@ describe('Resize dimensions', function () {
       });
   });
 
+  it('JPEG shrink-on-load with 90 degree rotation, ensure recalculation is correct', function (done) {
+    sharp(fixtures.inputJpg)
+      .resize(1920, 1280)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(1920, info.width);
+        assert.strictEqual(1280, info.height);
+        sharp(data)
+          .rotate(90)
+          .resize(533, 800)
+          .toBuffer(function (err, data, info) {
+            if (err) throw err;
+            assert.strictEqual(533, info.width);
+            assert.strictEqual(800, info.height);
+            done();
+          });
+      });
+  });
+
   it('TIFF embed known to cause rounding errors', function (done) {
     sharp(fixtures.inputTiff)
       .resize(240, 320)

test/unit/stats.js

@@ -24,6 +24,7 @@ describe('Image Stats', function () {
       if (err) throw err;
 
       assert.strictEqual(true, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 7.319914765248541));
 
       // red channel
       assert.strictEqual(0, stats.channels[0]['min']);
@@ -82,6 +83,7 @@ describe('Image Stats', function () {
       if (err) throw err;
 
       assert.strictEqual(true, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 0.3409031108021736));
 
       // red channel
       assert.strictEqual(0, stats.channels[0]['min']);
@@ -105,7 +107,9 @@ describe('Image Stats', function () {
   it('PNG with transparency', function (done) {
     sharp(fixtures.inputPngWithTransparency).stats(function (err, stats) {
       if (err) throw err;
+
       assert.strictEqual(false, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 0.06778064835816622));
 
       // red channel
       assert.strictEqual(0, stats.channels[0]['min']);
@@ -180,6 +184,7 @@ describe('Image Stats', function () {
       if (err) throw err;
 
       assert.strictEqual(false, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 0));
 
       // alpha channel
       assert.strictEqual(0, stats.channels[3]['min']);
@@ -204,7 +209,9 @@ describe('Image Stats', function () {
   it('Tiff', function (done) {
     sharp(fixtures.inputTiff).stats(function (err, stats) {
       if (err) throw err;
+
       assert.strictEqual(true, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 0.3851250782608986));
 
       // red channel
       assert.strictEqual(0, stats.channels[0]['min']);
@@ -231,6 +238,7 @@ describe('Image Stats', function () {
       if (err) throw err;
 
       assert.strictEqual(true, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 7.51758075132966));
 
       // red channel
       assert.strictEqual(0, stats.channels[0]['min']);
@@ -289,6 +297,7 @@ describe('Image Stats', function () {
       if (err) throw err;
 
       assert.strictEqual(true, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 6.087309412541799));
 
       // red channel
       assert.strictEqual(35, stats.channels[0]['min']);
@@ -345,7 +354,9 @@ describe('Image Stats', function () {
   it('Grayscale GIF with alpha', function (done) {
     sharp(fixtures.inputGifGreyPlusAlpha).stats(function (err, stats) {
       if (err) throw err;
+
       assert.strictEqual(false, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 1));
 
       // gray channel
       assert.strictEqual(0, stats.channels[0]['min']);
@@ -387,7 +398,9 @@ describe('Image Stats', function () {
     const readable = fs.createReadStream(fixtures.inputJpg);
     const pipeline = sharp().stats(function (err, stats) {
       if (err) throw err;
+
       assert.strictEqual(true, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 7.319914765248541));
 
       // red channel
       assert.strictEqual(0, stats.channels[0]['min']);
@@ -449,6 +462,7 @@ describe('Image Stats', function () {
 
     return pipeline.stats().then(function (stats) {
       assert.strictEqual(true, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 7.319914765248541));
 
       // red channel
       assert.strictEqual(0, stats.channels[0]['min']);
@@ -505,6 +519,7 @@ describe('Image Stats', function () {
   it('File in, Promise out', function () {
     return sharp(fixtures.inputJpg).stats().then(function (stats) {
       assert.strictEqual(true, stats.isOpaque);
+      assert.strictEqual(true, isInAcceptableRange(stats.entropy, 7.319914765248541));
 
       // red channel
       assert.strictEqual(0, stats.channels[0]['min']);

test/unit/tile.js

@@ -6,7 +6,7 @@ const assert = require('assert');
 
 const eachLimit = require('async/eachLimit');
 const rimraf = require('rimraf');
-const unzip = require('unzip');
+const DecompressZip = require('decompress-zip');
 
 const sharp = require('../../');
 const fixtures = require('../fixtures');
@@ -46,6 +46,51 @@ const assertDeepZoomTiles = function (directory, expectedSize, expectedLevels, d
   }, done);
 };
 
+const assertZoomifyTiles = function (directory, expectedTileSize, expectedLevels, done) {
+  fs.stat(path.join(directory, 'ImageProperties.xml'), function (err, stat) {
+    if (err) throw err;
+    assert.ok(stat.isFile());
+    assert.ok(stat.size > 0);
+
+    let maxTileLevel = -1;
+    fs.readdirSync(path.join(directory, 'TileGroup0')).forEach(function (tile) {
+      // Verify tile file name
+      assert.ok(/^[0-9]+-[0-9]+-[0-9]+\.jpg$/.test(tile));
+      let level = parseInt(tile.split('-')[0]);
+      maxTileLevel = Math.max(maxTileLevel, level);
+    });
+
+    assert.strictEqual(maxTileLevel + 1, expectedLevels); // add one to account for zero level tile
+
+    done();
+  });
+};
+
+const assertGoogleTiles = function (directory, expectedTileSize, expectedLevels, done) {
+  const levels = fs.readdirSync(directory);
+  assert.strictEqual(expectedLevels, levels.length - 1); // subtract one to account for default blank tile
+
+  fs.stat(path.join(directory, 'blank.png'), function (err, stat) {
+    if (err) throw err;
+    assert.ok(stat.isFile());
+    assert.ok(stat.size > 0);
+
+    // Basic check to confirm lowest and highest level tiles exist
+    fs.stat(path.join(directory, '0', '0', '0.jpg'), function (err, stat) {
+      if (err) throw err;
+      assert.strictEqual(true, stat.isFile());
+      assert.strictEqual(true, stat.size > 0);
+
+      fs.stat(path.join(directory, (expectedLevels - 1).toString(), '0', '0.jpg'), function (err, stat) {
+        if (err) throw err;
+        assert.strictEqual(true, stat.isFile());
+        assert.strictEqual(true, stat.size > 0);
+        done();
+      });
+    });
+  });
+};
+
 describe('Tile', function () {
   it('Valid size values pass', function () {
     [1, 8192].forEach(function (size) {
@@ -144,15 +189,60 @@ describe('Tile', function () {
     });
   });
 
+  it('Valid depths pass', function () {
+    ['onepixel', 'onetile', 'one'].forEach(function (depth) {
+      assert.doesNotThrow(function (depth) {
+        sharp().tile({
+          depth: depth
+        });
+      });
+    });
+  });
+
+  it('Invalid depths fail', function () {
+    ['depth', 1].forEach(function (depth) {
+      assert.throws(function () {
+        sharp().tile({
+          depth: depth
+        });
+      });
+    });
+  });
+
   it('Prevent larger overlap than default size', function () {
     assert.throws(function () {
-      sharp().tile({overlap: 257});
+      sharp().tile({
+        overlap: 257
+      });
     });
   });
 
   it('Prevent larger overlap than provided size', function () {
     assert.throws(function () {
-      sharp().tile({size: 512, overlap: 513});
+      sharp().tile({
+        size: 512,
+        overlap: 513
+      });
+    });
+  });
+
+  it('Valid rotation angle values pass', function () {
+    [90, 270, -90].forEach(function (angle) {
+      assert.doesNotThrow(function () {
+        sharp().tile({
+          angle: angle
+        });
+      });
+    });
+  });
+
+  it('Invalid rotation angle values fail', function () {
+    ['zoinks', 1.1, -1, 27].forEach(function (angle) {
+      assert.throws(function () {
+        sharp().tile({
+          angle: angle
+        });
+      });
     });
   });
 
@@ -192,6 +282,88 @@ describe('Tile', function () {
     });
   });
 
+  it('Deep Zoom layout with custom size+angle', function (done) {
+    const directory = fixtures.path('output.512_90.dzi_files');
+    rimraf(directory, function () {
+      sharp(fixtures.inputJpg)
+        .tile({
+          size: 512,
+          angle: 90
+        })
+        .toFile(fixtures.path('output.512_90.dzi'), function (err, info) {
+          if (err) throw err;
+          assert.strictEqual('dz', info.format);
+          assert.strictEqual(2725, info.width);
+          assert.strictEqual(2225, info.height);
+          assert.strictEqual(3, info.channels);
+          assert.strictEqual('undefined', typeof info.size);
+          assertDeepZoomTiles(directory, 512, 13, done);
+          // Verifies tiles in 10th level are rotated
+          let tile = path.join(directory, '10', '0_1.jpeg');
+          // verify that the width and height correspond to the rotated image
+          // expected are w=512 and h=170 for the 0_1.jpeg.
+          // if a 0 angle is supplied to the .tile function
+          // the expected values are w=170 and h=512 for the 1_0.jpeg
+          sharp(tile).metadata(function (err, metadata) {
+            if (err) {
+              throw err;
+            } else {
+              assert.strictEqual(true, metadata.width === 512);
+              assert.strictEqual(true, metadata.height === 170);
+            }
+          });
+        });
+    });
+  });
+
+  it('Deep Zoom layout with depth of one', function (done) {
+    const directory = fixtures.path('output.512_depth_one.dzi_files');
+    rimraf(directory, function () {
+      sharp(fixtures.inputJpg)
+        .tile({
+          size: 512,
+          depth: 'one'
+        })
+        .toFile(fixtures.path('output.512_depth_one.dzi'), function (err, info) {
+          if (err) throw err;
+          // Verify only one depth generated
+          assertDeepZoomTiles(directory, 512, 1, done);
+        });
+    });
+  });
+
+  it('Deep Zoom layout with depth of onepixel', function (done) {
+    const directory = fixtures.path('output.512_depth_onepixel.dzi_files');
+    rimraf(directory, function () {
+      sharp(fixtures.inputJpg)
+        .tile({
+          size: 512,
+          depth: 'onepixel'
+        })
+        .toFile(fixtures.path('output.512_depth_onepixel.dzi'), function (err, info) {
+          if (err) throw err;
+          // Verify only one depth generated
+          assertDeepZoomTiles(directory, 512, 13, done);
+        });
+    });
+  });
+
+  it('Deep Zoom layout with depth of onetile', function (done) {
+    const directory = fixtures.path('output.256_depth_onetile.dzi_files');
+    rimraf(directory, function () {
+      sharp(fixtures.inputJpg)
+        .tile({
+          size: 256,
+          depth: 'onetile'
+        })
+        .toFile(fixtures.path('output.256_depth_onetile.dzi'), function (err, info) {
+          if (err) throw err;
+          // Verify only one depth generated
+          assertDeepZoomTiles(directory, 256, 5, done);
+        });
+    });
+  });
+
   it('Zoomify layout', function (done) {
     const directory = fixtures.path('output.zoomify.dzi');
     rimraf(directory, function () {
@@ -216,6 +388,69 @@ describe('Tile', function () {
     });
   });
 
+  it('Zoomify layout with depth one', function (done) {
+    const directory = fixtures.path('output.zoomify.depth_one.dzi');
+    rimraf(directory, function () {
+      sharp(fixtures.inputJpg)
+        .tile({
+          size: 256,
+          layout: 'zoomify',
+          depth: 'one'
+        })
+        .toFile(directory, function (err, info) {
+          if (err) throw err;
+          assert.strictEqual('dz', info.format);
+          assert.strictEqual(2725, info.width);
+          assert.strictEqual(2225, info.height);
+          assert.strictEqual(3, info.channels);
+          assert.strictEqual('number', typeof info.size);
+          assertZoomifyTiles(directory, 256, 1, done);
+        });
+    });
+  });
+
+  it('Zoomify layout with depth onetile', function (done) {
+    const directory = fixtures.path('output.zoomify.depth_onetile.dzi');
+    rimraf(directory, function () {
+      sharp(fixtures.inputJpg)
+        .tile({
+          size: 256,
+          layout: 'zoomify',
+          depth: 'onetile'
+        })
+        .toFile(directory, function (err, info) {
+          if (err) throw err;
+          assert.strictEqual('dz', info.format);
+          assert.strictEqual(2725, info.width);
+          assert.strictEqual(2225, info.height);
+          assert.strictEqual(3, info.channels);
+          assert.strictEqual('number', typeof info.size);
+          assertZoomifyTiles(directory, 256, 5, done);
+        });
+    });
+  });
+
+  it('Zoomify layout with depth onepixel', function (done) {
+    const directory = fixtures.path('output.zoomify.depth_onepixel.dzi');
+    rimraf(directory, function () {
+      sharp(fixtures.inputJpg)
+        .tile({
+          size: 256,
+          layout: 'zoomify',
+          depth: 'onepixel'
+        })
+        .toFile(directory, function (err, info) {
+          if (err) throw err;
+          assert.strictEqual('dz', info.format);
+          assert.strictEqual(2725, info.width);
+          assert.strictEqual(2225, info.height);
+          assert.strictEqual(3, info.channels);
+          assert.strictEqual('number', typeof info.size);
+          assertZoomifyTiles(directory, 256, 13, done);
+        });
+    });
+  });
+
   it('Google layout', function (done) {
     const directory = fixtures.path('output.google.dzi');
     rimraf(directory, function () {
@@ -244,7 +479,9 @@ describe('Tile', function () {
     const directory = fixtures.path('output.jpg.google.dzi');
     rimraf(directory, function () {
       sharp(fixtures.inputJpg)
-        .jpeg({ quality: 1 })
+        .jpeg({
+          quality: 1
+        })
         .tile({
           layout: 'google'
         })
@@ -279,7 +516,9 @@ describe('Tile', function () {
     const directory = fixtures.path('output.png.google.dzi');
     rimraf(directory, function () {
       sharp(fixtures.inputJpg)
-        .png({ compressionLevel: 1 })
+        .png({
+          compressionLevel: 1
+        })
         .tile({
           layout: 'google'
         })
@@ -314,7 +553,9 @@ describe('Tile', function () {
     const directory = fixtures.path('output.webp.google.dzi');
     rimraf(directory, function () {
       sharp(fixtures.inputJpg)
-        .webp({ quality: 1 })
+        .webp({
+          quality: 1
+        })
         .tile({
           layout: 'google'
         })
@@ -345,6 +586,72 @@ describe('Tile', function () {
     });
   });
 
+  it('Google layout with depth one', function (done) {
+    const directory = fixtures.path('output.google_depth_one.dzi');
+    rimraf(directory, function () {
+      sharp(fixtures.inputJpg)
+        .tile({
+          layout: 'google',
+          depth: 'one',
+          size: 256
+        })
+        .toFile(directory, function (err, info) {
+          if (err) throw err;
+          assert.strictEqual('dz', info.format);
+          assert.strictEqual(2725, info.width);
+          assert.strictEqual(2225, info.height);
+          assert.strictEqual(3, info.channels);
+          assert.strictEqual('number', typeof info.size);
+
+          assertGoogleTiles(directory, 256, 1, done);
+        });
+    });
+  });
+
+  it('Google layout with depth onepixel', function (done) {
+    const directory = fixtures.path('output.google_depth_onepixel.dzi');
+    rimraf(directory, function () {
+      sharp(fixtures.inputJpg)
+        .tile({
+          layout: 'google',
+          depth: 'onepixel',
+          size: 256
+        })
+        .toFile(directory, function (err, info) {
+          if (err) throw err;
+          assert.strictEqual('dz', info.format);
+          assert.strictEqual(2725, info.width);
+          assert.strictEqual(2225, info.height);
+          assert.strictEqual(3, info.channels);
+          assert.strictEqual('number', typeof info.size);
+
+          assertGoogleTiles(directory, 256, 13, done);
+        });
+    });
+  });
+
+  it('Google layout with depth onetile', function (done) {
+    const directory = fixtures.path('output.google_depth_onetile.dzi');
+    rimraf(directory, function () {
+      sharp(fixtures.inputJpg)
+        .tile({
+          layout: 'google',
+          depth: 'onetile',
+          size: 256
+        })
+        .toFile(directory, function (err, info) {
+          if (err) throw err;
+          assert.strictEqual('dz', info.format);
+          assert.strictEqual(2725, info.width);
+          assert.strictEqual(2225, info.height);
+          assert.strictEqual(3, info.channels);
+          assert.strictEqual('number', typeof info.size);
+
+          assertGoogleTiles(directory, 256, 5, done);
+        });
+    });
+  });
+
   it('Write to ZIP container using file extension', function (done) {
     const container = fixtures.path('output.dz.container.zip');
     const extractTo = fixtures.path('output.dz.container');
@@ -362,12 +669,14 @@ describe('Tile', function () {
             if (err) throw err;
             assert.strictEqual(true, stat.isFile());
             assert.strictEqual(true, stat.size > 0);
-            fs.createReadStream(container)
-              .pipe(unzip.Extract({path: path.dirname(extractTo)}))
-              .on('error', function (err) { throw err; })
-              .on('close', function () {
+            new DecompressZip(container)
+              .on('extract', function () {
                 assertDeepZoomTiles(directory, 256, 13, done);
-              });
+              })
+              .on('error', function (err) {
+                throw err;
+              })
+              .extract({ path: path.dirname(extractTo) });
           });
         });
     });
@@ -394,12 +703,14 @@ describe('Tile', function () {
             if (err) throw err;
             assert.strictEqual(true, stat.isFile());
             assert.strictEqual(true, stat.size > 0);
-            fs.createReadStream(container)
-              .pipe(unzip.Extract({path: path.dirname(extractTo)}))
-              .on('error', function (err) { throw err; })
-              .on('close', function () {
+            new DecompressZip(container)
+              .on('extract', function () {
                 assertDeepZoomTiles(directory, 256, 13, done);
-              });
+              })
+              .on('error', function (err) {
+                throw err;
+              })
+              .extract({ path: path.dirname(extractTo) });
           });
         });
     });

test/unit/tint.js

@@ -0,0 +1,102 @@
+'use strict';
+
+const assert = require('assert');
+
+const sharp = require('../../');
+const fixtures = require('../fixtures');
+
+describe('Tint', function () {
+  it('tints rgb image red', function (done) {
+    const output = fixtures.path('output.tint-red.jpg');
+    sharp(fixtures.inputJpg)
+      .resize(320, 240)
+      .tint('#FF0000')
+      .toFile(output, function (err, info) {
+        if (err) throw err;
+        assert.strictEqual(true, info.size > 0);
+        fixtures.assertMaxColourDistance(output, fixtures.expected('tint-red.jpg'), 10);
+        done();
+      });
+  });
+
+  it('tints rgb image green', function (done) {
+    const output = fixtures.path('output.tint-green.jpg');
+    sharp(fixtures.inputJpg)
+      .resize(320, 240)
+      .tint('#00FF00')
+      .toFile(output, function (err, info) {
+        if (err) throw err;
+        assert.strictEqual(true, info.size > 0);
+        fixtures.assertMaxColourDistance(output, fixtures.expected('tint-green.jpg'), 10);
+        done();
+      });
+  });
+
+  it('tints rgb image blue', function (done) {
+    const output = fixtures.path('output.tint-blue.jpg');
+    sharp(fixtures.inputJpg)
+      .resize(320, 240)
+      .tint('#0000FF')
+      .toFile(output, function (err, info) {
+        if (err) throw err;
+        assert.strictEqual(true, info.size > 0);
+        fixtures.assertMaxColourDistance(output, fixtures.expected('tint-blue.jpg'), 10);
+        done();
+      });
+  });
+
+  it('tints rgb image with sepia tone', function (done) {
+    const output = fixtures.path('output.tint-sepia.jpg');
+    sharp(fixtures.inputJpg)
+      .resize(320, 240)
+      .tint('#704214')
+      .toFile(output, function (err, info) {
+        if (err) throw err;
+        assert.strictEqual(320, info.width);
+        assert.strictEqual(240, info.height);
+        fixtures.assertMaxColourDistance(output, fixtures.expected('tint-sepia.jpg'), 10);
+        done();
+      });
+  });
+
+  it('tints rgb image with sepia tone with rgb colour', function (done) {
+    const output = fixtures.path('output.tint-sepia.jpg');
+    sharp(fixtures.inputJpg)
+      .resize(320, 240)
+      .tint([112, 66, 20])
+      .toFile(output, function (err, info) {
+        if (err) throw err;
+        assert.strictEqual(320, info.width);
+        assert.strictEqual(240, info.height);
+        fixtures.assertMaxColourDistance(output, fixtures.expected('tint-sepia.jpg'), 10);
+        done();
+      });
+  });
+
+  it('tints rgb image with alpha channel', function (done) {
+    const output = fixtures.path('output.tint-alpha.png');
+    sharp(fixtures.inputPngRGBWithAlpha)
+      .resize(320, 240)
+      .tint('#704214')
+      .toFile(output, function (err, info) {
+        if (err) throw err;
+        assert.strictEqual(320, info.width);
+        assert.strictEqual(240, info.height);
+        fixtures.assertMaxColourDistance(output, fixtures.expected('tint-alpha.png'), 10);
+        done();
+      });
+  });
+
+  it('tints cmyk image red', function (done) {
+    const output = fixtures.path('output.tint-cmyk.jpg');
+    sharp(fixtures.inputJpgWithCmykProfile)
+      .resize(320, 240)
+      .tint('#FF0000')
+      .toFile(output, function (err, info) {
+        if (err) throw err;
+        assert.strictEqual(true, info.size > 0);
+        fixtures.assertMaxColourDistance(output, fixtures.expected('tint-cmyk.jpg'), 10);
+        done();
+      });
+  });
+});