Release v0.20.8

Metadata output will still remain integer

docs/api-channel.md

@@ -1,5 +1,21 @@
 <!-- Generated by documentation.js. Update this documentation by updating the source code. -->
 
+## removeAlpha
+
+Remove alpha channel, if any. This is a no-op if the image does not have an alpha channel.
+
+### Examples
+
+```javascript
+sharp('rgba.png')
+  .removeAlpha()
+  .toFile('rgb.png', function(err, info) {
+    // rgb.png is a 3 channel image without an alpha channel
+  });
+```
+
+Returns **Sharp** 
+
 ## extractChannel
 
 Extract a single channel from a multi-channel image.

docs/api-composite.md

@@ -18,7 +18,7 @@ If the overlay image contains an alpha channel then composition with premultipli
     -   `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.density` **[Number][4]** 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]?** 
@@ -40,8 +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

docs/api-constructor.md

@@ -12,7 +12,7 @@
     -   `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][5]** integral number representing the DPI for vector images. (optional, default `72`)
+    -   `options.density` **[Number][5]** 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]?** 
@@ -55,7 +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()

docs/api-input.md

@@ -79,6 +79,7 @@ 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
 

docs/api-output.md

@@ -121,6 +121,8 @@ Use these JPEG options for output image.
     -   `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
@@ -276,6 +278,7 @@ Warning: multiple sharp instances concurrently producing tile output can expose
     -   `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'`)
 

docs/changelog.md

@@ -4,6 +4,52 @@
 
 Requires libvips v8.6.1.
 
+#### v0.20.8 - 5<sup>th</sup> September 2018
+
+* Avoid race conditions when creating directories during installation.
+  [#1358](https://github.com/lovell/sharp/pull/1358)
+  [@ajhool](https://github.com/ajhool)
+
+* Accept floating point values for input density parameter.
+  [#1362](https://github.com/lovell/sharp/pull/1362)
+  [@aeirola](https://github.com/aeirola)
+
+#### 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.

docs/index.md

@@ -113,6 +113,11 @@ the help and code contributions of the following people:
 * [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)
+* [Aidan Hoolachan](https://github.com/ajhool)
+* [Axel Eirola](https://github.com/aeirola)
 
 Thank you!
 

install/dll-copy.js

@@ -4,6 +4,7 @@ const fs = require('fs');
 const path = require('path');
 
 const copyFileSync = require('fs-copy-file-sync');
+const libvips = require('../lib/libvips');
 const npmLog = require('npmlog');
 
 if (process.platform === 'win32') {
@@ -11,8 +12,8 @@ if (process.platform === 'win32') {
   const buildReleaseDir = path.join(buildDir, 'Release');
   npmLog.info('sharp', `Creating ${buildReleaseDir}`);
   try {
-    fs.mkdirSync(buildDir);
-    fs.mkdirSync(buildReleaseDir);
+    libvips.mkdirSync(buildDir);
+    libvips.mkdirSync(buildReleaseDir);
   } catch (err) {}
   const vendorLibDir = path.join(__dirname, '..', 'vendor', 'lib');
   npmLog.info('sharp', `Copying DLLs from ${vendorLibDir} to ${buildReleaseDir}`);

install/libvips.js

@@ -9,6 +9,7 @@ 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');
@@ -17,6 +18,20 @@ 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');
+  libvips.mkdirSync(vendorPath);
+  tar
+    .extract({
+      file: tarPath,
+      cwd: vendorPath,
+      strict: true
+    })
+    .catch(function (err) {
+      throw err;
+    });
+};
+
 try {
   const useGlobalLibvips = libvips.useGlobalLibvips();
   if (useGlobalLibvips) {
@@ -29,11 +44,15 @@ try {
   } else {
     // Is this arch/platform supported?
     const arch = process.env.npm_config_arch || process.arch;
-    if (platform() === 'win32-ia32') {
+    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}\n`);
+      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}`);
@@ -42,38 +61,37 @@ try {
       throw new Error(`Use with glibc version ${detectLibc.version} requires manual installation of libvips >= ${minimumLibvipsVersion}`);
     }
     // Download to per-process temporary file
-    const tarFilename = ['libvips', minimumLibvipsVersion, platform()].join('-') + '.tar.gz';
-    const tarPathTemp = path.join(os.tmpdir(), `${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 () {
-      const vendorPath = path.join(__dirname, '..', 'vendor');
-      fs.mkdirSync(vendorPath);
-      tar
-        .extract({
-          file: tarPathTemp,
-          cwd: vendorPath,
-          strict: true
-        })
-        .then(function () {
-          try {
-            fs.unlinkSync(tarPathTemp);
-          } catch (err) {}
-        })
-        .catch(function (err) {
+    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);

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/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
@@ -35,7 +34,7 @@ const is = require('./is');
  * @param {Number} [options.left] - the pixel offset from the left edge.
  * @param {Boolean} [options.tile=false] - set to true to repeat the overlay image across the entire image with the given `gravity`.
  * @param {Boolean} [options.cutout=false] - 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.
- * @param {Number} [options.density=72] - integral number representing the DPI for vector overlay image.
+ * @param {Number} [options.density=72] - number representing the DPI for vector overlay image.
  * @param {Object} [options.raw] - describes overlay when using raw pixel data.
  * @param {Number} [options.raw.width]
  * @param {Number} [options.raw.height]

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()
@@ -96,7 +96,7 @@ const debuglog = util.debuglog('sharp');
  * @param {Boolean} [options.failOnError=false] - 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.
- * @param {Number} [options.density=72] - integral number representing the DPI for vector images.
+ * @param {Number} [options.density=72] - 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]
@@ -171,6 +171,7 @@ const Sharp = function (input, options) {
     booleanFileIn: '',
     joinChannelIn: [],
     extractChannel: -1,
+    removeAlpha: false,
     colourspace: 'srgb',
     // overlay
     overlayGravity: 0,
@@ -193,6 +194,7 @@ const Sharp = function (input, options) {
     jpegOvershootDeringing: false,
     jpegOptimiseScans: false,
     jpegOptimiseCoding: true,
+    jpegQuantisationTable: 0,
     pngProgressive: false,
     pngCompressionLevel: 9,
     pngAdaptiveFiltering: false,

lib/input.js

@@ -36,7 +36,7 @@ function _createInputDescriptor (input, inputOptions, containerOptions) {
     }
     // Density
     if (is.defined(inputOptions.density)) {
-      if (is.integer(inputOptions.density) && is.inRange(inputOptions.density, 1, 2400)) {
+      if (is.inRange(inputOptions.density, 1, 2400)) {
         inputDescriptor.density = inputOptions.density;
       } else {
         throw new Error('Invalid density (1 to 2400) ' + inputOptions.density);
@@ -264,6 +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

@@ -1,17 +1,38 @@
 '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 minimumLibvipsVersion = process.env.npm_package_config_libvips || require('../package.json').config.libvips;
+const env = process.env;
+const minimumLibvipsVersion = env.npm_package_config_libvips || require('../package.json').config.libvips;
 
 const spawnSyncOptions = {
   encoding: 'utf8',
   shell: true
 };
 
+const mkdirSync = function (dirPath) {
+  try {
+    fs.mkdirSync(dirPath);
+  } catch (err) {
+    if (err.code !== 'EEXIST') {
+      throw err;
+    }
+  }
+};
+
+const cachePath = function () {
+  const npmCachePath = env.npm_config_cache || (env.APPDATA ? path.join(env.APPDATA, 'npm-cache') : path.join(os.homedir(), '.npm'));
+  mkdirSync(npmCachePath);
+  const libvipsCachePath = path.join(npmCachePath, '_libvips');
+  mkdirSync(libvipsCachePath);
+  return libvipsCachePath;
+};
+
 const globalLibvipsVersion = function () {
   if (process.platform !== 'win32') {
     const globalLibvipsVersion = spawnSync(`PKG_CONFIG_PATH="${pkgConfigPath()}" pkg-config --modversion vips-cpp`, spawnSyncOptions).stdout || '';
@@ -23,21 +44,24 @@ const globalLibvipsVersion = function () {
 
 const hasVendoredLibvips = function () {
   const currentPlatformId = platform();
+  let vendorPlatformId;
   try {
-    const vendorPlatformId = require(path.join(__dirname, '..', 'vendor', 'platform.json'));
+    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'.`);
     }
-  } catch (err) {}
+  }
   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(), process.env.PKG_CONFIG_PATH, '/usr/local/lib/pkgconfig', '/usr/lib/pkgconfig']
+    return [brewPkgConfigPath.trim(), env.PKG_CONFIG_PATH, '/usr/local/lib/pkgconfig', '/usr/lib/pkgconfig']
       .filter(function (p) { return !!p; })
       .join(':');
   } else {
@@ -46,7 +70,7 @@ const pkgConfigPath = function () {
 };
 
 const useGlobalLibvips = function () {
-  if (Boolean(process.env.SHARP_IGNORE_GLOBAL_LIBVIPS) === true) {
+  if (Boolean(env.SHARP_IGNORE_GLOBAL_LIBVIPS) === true) {
     return false;
   }
 
@@ -56,8 +80,10 @@ const useGlobalLibvips = function () {
 
 module.exports = {
   minimumLibvipsVersion: minimumLibvipsVersion,
+  cachePath: cachePath,
   globalLibvipsVersion: globalLibvipsVersion,
   hasVendoredLibvips: hasVendoredLibvips,
   pkgConfigPath: pkgConfigPath,
-  useGlobalLibvips: useGlobalLibvips
+  useGlobalLibvips: useGlobalLibvips,
+  mkdirSync: mkdirSync
 };

lib/output.js

@@ -150,6 +150,8 @@ function withMetadata (withMetadata) {
  * @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
@@ -191,6 +193,14 @@ function jpeg (options) {
     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);
 }
@@ -261,10 +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)) {
@@ -413,6 +423,7 @@ function toFormat (format, options) {
  * @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}
@@ -464,6 +475,15 @@ function tile (tile) {
         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'])) {

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": "0.20.5",
+  "version": "0.20.8",
   "author": "Lovell Fuller <npm@lovell.info>",
   "homepage": "https://github.com/lovell/sharp",
   "contributors": [
@@ -49,7 +49,12 @@
     "Rik Heywood <rik@rik.org>",
     "Thomas Parisot <hi@oncletom.io>",
     "Nathan Graves <nathanrgraves+github@gmail.com>",
-    "Tom Lokhorst <tom@lokhorst.eu>"
+    "Tom Lokhorst <tom@lokhorst.eu>",
+    "Espen Hovlandsdal <espen@hovlandsdal.com>",
+    "Sylvain Dumont <sylvain.dumont35@gmail.com>",
+    "Alun Davies <alun.owain.davies@googlemail.com>",
+    "Aidan Hoolachan <ajhoolachan21@gmail.com>",
+    "Axel Eirola <axel.eirola@iki.fi>"
   ],
   "scripts": {
     "install": "(node install/libvips && node install/dll-copy && prebuild-install) || (node-gyp rebuild && node install/dll-copy)",
@@ -83,25 +88,26 @@
   "dependencies": {
     "color": "^3.0.0",
     "detect-libc": "^1.0.3",
-    "nan": "^2.10.0",
+    "nan": "^2.11.0",
     "fs-copy-file-sync": "^1.1.1",
     "npmlog": "^4.1.2",
     "prebuild-install": "^4.0.0",
-    "semver": "^5.5.0",
+    "semver": "^5.5.1",
     "simple-get": "^2.8.1",
-    "tar": "^4.4.4",
+    "tar": "^4.4.6",
     "tunnel-agent": "^0.6.0"
   },
   "devDependencies": {
     "async": "^2.6.1",
     "cc": "^1.0.2",
     "decompress-zip": "^0.3.1",
-    "documentation": "^8.0.0",
+    "documentation": "^8.1.2",
     "exif-reader": "^1.0.2",
     "icc": "^1.0.0",
     "mocha": "^5.2.0",
-    "nyc": "^12.0.2",
-    "prebuild": "^7.6.0",
+    "mock-fs": "^4.6.0",
+    "nyc": "^12.0.1",
+    "prebuild": "^7.6.2",
     "prebuild-ci": "^2.2.3",
     "rimraf": "^2.6.2",
     "semistandard": "^12.0.1"

src/common.cc

@@ -55,7 +55,7 @@ namespace sharp {
     descriptor->failOnError = AttrTo<bool>(input, "failOnError");
     // Density for vector-based input
     if (HasAttr(input, "density")) {
-      descriptor->density = AttrTo<uint32_t>(input, "density");
+      descriptor->density = AttrTo<double>(input, "density");
     }
     // Raw pixel input
     if (HasAttr(input, "rawChannels")) {
@@ -228,7 +228,7 @@ namespace sharp {
               ->set("access", accessMethod)
               ->set("fail", descriptor->failOnError);
             if (imageType == ImageType::SVG || imageType == ImageType::PDF) {
-              option->set("dpi", static_cast<double>(descriptor->density));
+              option->set("dpi", descriptor->density);
             }
             if (imageType == ImageType::MAGICK) {
               option->set("density", std::to_string(descriptor->density).data());
@@ -270,7 +270,7 @@ namespace sharp {
               ->set("access", accessMethod)
               ->set("fail", descriptor->failOnError);
             if (imageType == ImageType::SVG || imageType == ImageType::PDF) {
-              option->set("dpi", static_cast<double>(descriptor->density));
+              option->set("dpi", descriptor->density);
             }
             if (imageType == ImageType::MAGICK) {
               option->set("density", std::to_string(descriptor->density).data());
@@ -355,8 +355,8 @@ namespace sharp {
   /*
     Set pixels/mm resolution based on a pixels/inch density.
   */
-  void SetDensity(VImage image, const int density) {
-    const double pixelsPerMm = static_cast<double>(density) / 25.4;
+  void SetDensity(VImage image, const double density) {
+    const double pixelsPerMm = density / 25.4;
     image.set("Xres", pixelsPerMm);
     image.set("Yres", pixelsPerMm);
     image.set(VIPS_META_RESOLUTION_UNIT, "in");

src/common.h

@@ -49,7 +49,7 @@ namespace sharp {
     char *buffer;
     bool failOnError;
     size_t bufferLength;
-    int density;
+    double density;
     int rawChannels;
     int rawWidth;
     int rawHeight;
@@ -63,7 +63,7 @@ namespace sharp {
       buffer(nullptr),
       failOnError(FALSE),
       bufferLength(0),
-      density(72),
+      density(72.0),
       rawChannels(0),
       rawWidth(0),
       rawHeight(0),
@@ -186,7 +186,7 @@ namespace sharp {
   /*
     Set pixels/mm resolution based on a pixels/inch density.
   */
-  void SetDensity(VImage image, const int density);
+  void SetDensity(VImage image, const double density);
 
   /*
     Check the proposed format supports the current dimensions.

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
@@ -223,10 +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));
     }
@@ -374,10 +382,8 @@ namespace sharp {
   VImage Linear(VImage image, double const a, double const b) {
     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.linear(a, b).bandjoin(alpha);
+      return RemoveAlpha(image).linear(a, b).bandjoin(alpha);
     } else {
       return image.linear(a, b);
     }

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.

src/pipeline.cc

@@ -694,10 +694,19 @@ class PipelineWorker : public Nan::AsyncWorker {
           (baton->err).append("Cannot extract channel from image. Too few channels in image.");
           return Error();
         }
+        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", VIPS_INTERPRETATION_B_W));
+          .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);
@@ -733,6 +742,7 @@ 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", baton->jpegOptimiseCoding)));
@@ -848,6 +858,7 @@ 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", baton->jpegOptimiseCoding));
@@ -927,6 +938,7 @@ 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", baton->jpegOptimiseCoding ? "TRUE": "FALSE"}
@@ -934,14 +946,22 @@ class PipelineWorker : public Nan::AsyncWorker {
             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()))
-            ->set("angle", CalculateAngleRotation(baton->tileAngle)));
+          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)) {
@@ -1232,6 +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"));
@@ -1266,6 +1287,7 @@ 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");
@@ -1307,6 +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 ||

src/pipeline.h

@@ -102,6 +102,7 @@ struct PipelineBaton {
   bool jpegProgressive;
   std::string jpegChromaSubsampling;
   bool jpegTrellisQuantisation;
+  int jpegQuantisationTable;
   bool jpegOvershootDeringing;
   bool jpegOptimiseScans;
   bool jpegOptimiseCoding;
@@ -130,6 +131,7 @@ struct PipelineBaton {
   VipsOperationBoolean booleanOp;
   VipsOperationBoolean bandBoolOp;
   int extractChannel;
+  bool removeAlpha;
   VipsInterpretation colourspace;
   int tileSize;
   int tileOverlap;
@@ -137,6 +139,7 @@ struct PipelineBaton {
   VipsForeignDzLayout tileLayout;
   std::string tileFormat;
   int tileAngle;
+  VipsForeignDzDepth tileDepth;
 
   PipelineBaton():
     input(nullptr),
@@ -188,6 +191,7 @@ struct PipelineBaton {
     jpegProgressive(false),
     jpegChromaSubsampling("4:2:0"),
     jpegTrellisQuantisation(false),
+    jpegQuantisationTable(0),
     jpegOvershootDeringing(false),
     jpegOptimiseScans(false),
     jpegOptimiseCoding(true),
@@ -211,12 +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),
-    tileAngle(0){
+    tileAngle(0),
+    tileDepth(VIPS_FOREIGN_DZ_DEPTH_LAST){
       background[0] = 0.0;
       background[1] = 0.0;
       background[2] = 0.0;

src/stats.cc

@@ -59,7 +59,6 @@ class StatsWorker : public Nan::AsyncWorker {
     using sharp::MaximumImageAlpha;
 
     vips::VImage image;
-    vips::VImage stats;
     sharp::ImageType imageType = sharp::ImageType::UNKNOWN;
 
     try {
@@ -69,9 +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()),
@@ -83,11 +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());
       }
@@ -130,6 +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;
     }
 

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/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/extractChannel.js

@@ -69,6 +69,17 @@ describe('Image channel extraction', function () {
       });
   });
 
+  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)
@@ -856,6 +866,37 @@ describe('Input/output', function () {
       });
   });
 
+  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)
@@ -898,6 +939,21 @@ describe('Input/output', function () {
       });
   });
 
+  it('Convert SVG to PNG at 14.4DPI', function (done) {
+    sharp(fixtures.inputSvg, { density: 14.4 })
+      .toFormat('png')
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('png', info.format);
+        assert.strictEqual(20, info.width);
+        assert.strictEqual(20, info.height);
+        fixtures.assertSimilar(fixtures.expected('svg14.4.png'), data, function (err) {
+          if (err) throw err;
+          done();
+        });
+      });
+  });
+
   it('Convert SVG with embedded images to PNG, respecting dimensions, autoconvert to PNG', function (done) {
     sharp(fixtures.inputSvgWithEmbeddedImages)
       .toBuffer(function (err, data, info) {
@@ -1465,11 +1521,6 @@ describe('Input/output', function () {
         sharp(null, { density: 'zoinks' });
       });
     });
-    it('Invalid density: float', function () {
-      assert.throws(function () {
-        sharp(null, { density: 0.5 });
-      });
-    });
     it('Ignore unknown attribute', function () {
       sharp(null, { unknown: true });
     });

test/unit/libvips.js

@@ -1,8 +1,10 @@
 'use strict';
 
 const assert = require('assert');
+const fs = require('fs');
 const semver = require('semver');
 const libvips = require('../../lib/libvips');
+const mockFS = require('mock-fs');
 
 const originalPlatform = process.platform;
 
@@ -66,5 +68,41 @@ describe('libvips binaries', function () {
 
       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));
+    });
+  });
+
+  describe('safe directory creation', function () {
+    before(function () {
+      mockFS({
+        exampleDirA: {
+          exampleDirB: {
+            exampleFile: 'Example test file'
+          }
+        }
+      });
+    });
+    after(function () { mockFS.restore(); });
+
+    it('mkdirSync creates a directory', function () {
+      const dirPath = 'createdDir';
+
+      libvips.mkdirSync(dirPath);
+      assert.strictEqual(true, fs.existsSync(dirPath));
+    });
+    it('mkdirSync does not throw error or overwrite an existing dir', function () {
+      const dirPath = 'exampleDirA';
+      const nestedDirPath = 'exampleDirA/exampleDirB';
+      assert.strictEqual(true, fs.existsSync(dirPath));
+
+      libvips.mkdirSync(dirPath);
+
+      assert.strictEqual(true, fs.existsSync(dirPath));
+      assert.strictEqual(true, fs.existsSync(nestedDirPath));
+    });
   });
 });

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

@@ -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) {
@@ -144,6 +189,26 @@ 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({
@@ -251,6 +316,54 @@ describe('Tile', function () {
     });
   });
 
+  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 () {
@@ -275,6 +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 () {
@@ -410,6 +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');