Update perf test results ahead of v0.12.0

Benchmark test updates ahead of v0.12.0
Version bump of libpng Windows dependency
2026-02-04 13:46:19 +01:00 · 2015-11-23 13:09:06 +00:00 · 2015-11-23 10:53:52 +00:00 · 2015-11-22 21:11:29 +00:00 · 2015-11-22 20:58:38 +00:00 · 2015-11-22 09:39:42 +00:00
105 changed files with 2381 additions and 1041 deletions
--- a/.editorconfig
+++ b/.editorconfig
@@ -0,0 +1,12 @@
+# http://editorconfig.org
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false
--- a/.gitignore
+++ b/.gitignore
@@ -6,4 +6,6 @@ test/fixtures/output*
 test/leak/libvips.supp
 lib
 include
+packaging/libvips*
+packaging/*.log
 .DS_Store
--- a/.npmignore
+++ b/.npmignore
@@ -7,6 +7,8 @@ coverage
 test
 .travis.yml
 appveyor.yml
+circle.yml
 mkdocs.yml
 lib
 include
+packaging
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,18 +2,16 @@ language: node_js
 node_js:
  - "0.10"
  - "0.12"
-  - "iojs-v2"
-  - "iojs-v3"
  - "4"
-sudo: 9000
+  - "5"
+sudo: false
 addons:
  apt:
    sources:
    - ubuntu-toolchain-r-test
    packages:
    - g++-4.8
-before_install:
-  - sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.8 90
-  - curl -s https://raw.githubusercontent.com/lovell/sharp/master/preinstall.sh | sudo bash -
+env:
+  CXX=g++-4.8
 after_success:
  - cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -6,16 +6,10 @@ Hello, thank you for your interest in helping!

 Please create a [new issue](https://github.com/lovell/sharp/issues/new) containing the steps to reproduce the problem.

+If you're having installation problems, please include the output of running `npm install --verbose sharp`.
+
 New bugs are assigned a `triage` label whilst under investigation.

-If you're having problems with `npm install sharp`, please include the output of the following commands, perhaps as a [gist](https://gist.github.com/):
-
-```sh
-vips -v
-pkg-config --print-provides vips
-npm install --verbose sharp
-```
-
 ## Submit a new feature request

 If a [similar request](https://github.com/lovell/sharp/labels/enhancement) exists, it's probably fastest to add a comment to it about your requirement.
@@ -47,7 +41,6 @@ Any change that modifies the existing public API should be added to the relevant

 | Release | WIP branch |
 | ------: | :--------- |
-| v0.11.0 | knife      |
 | v0.12.0 | look       |
 | v0.13.0 | mind       |

@@ -85,6 +78,15 @@ 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 [new issue](https://github.com/lovell/sharp/issues/new) or contact me by [e-mail](https://github.com/lovell/sharp/blob/master/package.json#L4).
--- a/README.md
+++ b/README.md
@@ -4,13 +4,30 @@ The typical use case for this high speed Node.js module
 is to convert large images of many formats to
 smaller, web-friendly JPEG, PNG and WebP images of varying dimensions.

+Resizing an image is typically 4x faster than using the
+quickest ImageMagick and GraphicsMagick settings.
+
+Colour spaces, embedded ICC profiles and alpha transparency channels are all handled correctly.
+Bicubic interpolation with Lanczos anti-alias filtering ensures quality is not sacrificed for speed.
+
+As well as image resizing, operations such as
+rotation, extraction, compositing and gamma correction are available.
+
+64-bit Windows and recent Linux systems do not require
+the installation of any external runtime dependencies.
+
+Use with OS X is as simple as running `brew install homebrew/science/vips`
+to install the libvips dependency.
+
 [![Test Coverage](https://coveralls.io/repos/lovell/sharp/badge.png?branch=master)](https://coveralls.io/r/lovell/sharp?branch=master)

 ### Documentation

-Visit [sharp.dimens.io](http://sharp.dimens.io/) for
-complete installation instructions, API documentation,
-benchmark tests and a changelog.
+Visit [sharp.dimens.io](http://sharp.dimens.io/) for complete
+[installation instructions](http://sharp.dimens.io/page/install),
+[API documentation](http://sharp.dimens.io/page/api),
+[benchmark tests](http://sharp.dimens.io/page/performance) and
+[changelog](http://sharp.dimens.io/page/changelog).

 ### Contributing

--- a/appveyor.yml
+++ b/appveyor.yml
@@ -3,26 +3,13 @@ version: "{build}"
 build: off
 platform: x64
 environment:
-  VIPS_VERSION_MAJOR_MINOR: 8.1
-  VIPS_VERSION_PATCH: 1
  VIPS_WARNING: 0
  matrix:
  - nodejs_version: "0.12"
-    nodejs_exec: "node"
-  - nodejs_version: "2"
-    nodejs_exec: "iojs"
-  - nodejs_version: "3"
-    nodejs_exec: "iojs"
  - nodejs_version: "4"
-    nodejs_exec: "node"
+  - nodejs_version: "5"
 install:
-  - ps: $env:VIPS_VERSION = "$env:VIPS_VERSION_MAJOR_MINOR.$env:VIPS_VERSION_PATCH"
-  - ps: Write-Output "Fetching http://www.vips.ecs.soton.ac.uk/supported/$env:VIPS_VERSION_MAJOR_MINOR/win32/vips-dev-$env:VIPS_VERSION.zip"
-  - ps: Start-FileDownload http://www.vips.ecs.soton.ac.uk/supported/$env:VIPS_VERSION_MAJOR_MINOR/win32/vips-dev-$env:VIPS_VERSION.zip -FileName c:\vips-dev-$env:VIPS_VERSION.zip
-  - ps: Invoke-Expression "& 7z -y x c:\vips-dev-$env:VIPS_VERSION.zip -oc:\ | FIND /V `"ing  `""
-  - ps: $env:VIPS_HOME = "c:\vips-dev-$env:VIPS_VERSION"
-  - ps: $env:PATH = "$env:VIPS_HOME\bin;$env:PATH"
-  - ps: Install-Product node $env:nodejs_version x86
-  - npm install --arch=ia32
+  - ps: Install-Product node $env:nodejs_version x64
+  - npm install
 test_script:
-  - npm run-script test-win32-%nodejs_exec%
+  - npm run-script test-win
--- a/binding.gyp
+++ b/binding.gyp
@@ -1,8 +1,39 @@
 {
  'targets': [{
    'target_name': 'sharp',
+    # Nested variables "pattern" borrowed from http://src.chromium.org/viewvc/chrome/trunk/src/build/common.gypi
    'variables': {
-      'runtime_link%':'shared', 
+      '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 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()")'
+        }, {
+          'use_global_vips': ''
+        }]
+      ]
    },
    'sources': [
      'src/common.cc',
@@ -12,55 +43,70 @@
      'src/sharp.cc',
      'src/utilities.cc'
    ],
+    'include_dirs': [
+      '<!(node -e "require(\'nan\')")'
+    ],
    'conditions': [
-        ['OS=="win"', {
-            'library_dirs': [
-                '$(VIPS_HOME)/lib'
-            ],
-            'libraries': [
-                'libvips.dll.a',
-                'glib-2.0.lib',
-                'gobject-2.0.lib',
-                'gthread-2.0.lib',
-                'gmodule-2.0.lib',
-                'liblcms2.dll.a',
-                'libxml2.lib',
-                'intl.lib',
-                'libjpeg.dll.a',
-                'libexif.dll.a',
-                'libpng.lib',
-                'libtiff.dll.a',
-                'libMagickWand-6.Q16.dll.a',
-                'libMagickCore-6.Q16.dll.a',
-                'pango-1.0.lib',
-                'pangoft2-1.0.lib',
-                'libgsf-1.dll.a',
-                'libopenslide.dll.a',
-                'libfftw3.dll.a'
-            ],
-            'include_dirs': [
-                '$(VIPS_HOME)/include',
-                '$(VIPS_HOME)/include/glib-2.0',
-                '$(VIPS_HOME)/lib/glib-2.0/include',
-                '<!(node -e "require(\'nan\')")'
-            ]
-        }, {
+      ['use_global_vips == "true"', {
+        # Use pkg-config for include and lib
+        'include_dirs': ['<!(PKG_CONFIG_PATH="<(pkg_config_path)" pkg-config --cflags vips glib-2.0)'],
+        'conditions': [
+          ['runtime_link == "static"', {
+            'libraries': ['<!(PKG_CONFIG_PATH="<(pkg_config_path)" pkg-config --libs vips --static)']
+          }, {
+            'libraries': ['<!(PKG_CONFIG_PATH="<(pkg_config_path)" pkg-config --libs vips)']
+          }]
+        ]
+      }, {
+        # Attempt to download pre-built libvips and install locally within node_modules
+        'include_dirs': [
+          '<(module_root_dir)/include',
+          '<(module_root_dir)/include/glib-2.0',
+          '<(module_root_dir)/lib/glib-2.0/include'
+        ],
+        'conditions': [
+          ['OS == "win"', {
            'variables': {
-                'PKG_CONFIG_PATH': '<!(which brew >/dev/null 2>&1 && eval $(brew --env) && echo $PKG_CONFIG_LIBDIR || true):$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig:/usr/lib/pkgconfig'
+              'download_vips': '<!(node -e "require(\'./binding\').download_vips()")'
            },
            'libraries': [
-                '<!(PKG_CONFIG_PATH="<(PKG_CONFIG_PATH)" pkg-config --libs vips)'
-            ],
-            'include_dirs': [
-                '<!(PKG_CONFIG_PATH="<(PKG_CONFIG_PATH)" pkg-config --cflags vips glib-2.0)',
-                '<!(node -e "require(\'nan\')")'
-            ],
-            'conditions': [
-                ['runtime_link == "static"', {
-                  'libraries': ['<!(PKG_CONFIG_PATH="<(PKG_CONFIG_PATH)" pkg-config --libs vips --static)']
-                }]
+              '<(module_root_dir)/lib/libvips.lib',
+              '<(module_root_dir)/lib/libglib-2.0.lib',
+              '<(module_root_dir)/lib/libgobject-2.0.lib'
            ]
-        }]
+          }],
+          ['OS == "linux"', {
+            'variables': {
+              'download_vips': '<!(LDD_VERSION="<!(ldd --version 2>&1 || true)" node -e "require(\'./binding\').download_vips()")'
+            },
+            'libraries': [
+              '<(module_root_dir)/lib/libvips.so',
+              '<(module_root_dir)/lib/libglib-2.0.so',
+              '<(module_root_dir)/lib/libgobject-2.0.so',
+              # Dependencies of dependencies, included for openSUSE support
+              '<(module_root_dir)/lib/libMagickCore-6.Q16.so',
+              '<(module_root_dir)/lib/libMagickWand-6.Q16.so',
+              '<(module_root_dir)/lib/libexif.so',
+              '<(module_root_dir)/lib/libgio-2.0.so',
+              '<(module_root_dir)/lib/libgmodule-2.0.so',
+              '<(module_root_dir)/lib/libgsf-1.so',
+              '<(module_root_dir)/lib/libjpeg.so',
+              '<(module_root_dir)/lib/libpng.so',
+              '<(module_root_dir)/lib/libtiff.so',
+              '<(module_root_dir)/lib/libwebp.so',
+              '<(module_root_dir)/lib/libz.so',
+              '<(module_root_dir)/lib/libffi.so',
+              '<(module_root_dir)/lib/libgthread-2.0.so',
+              '<(module_root_dir)/lib/liblcms2.so',
+              '<(module_root_dir)/lib/libpng16.so',
+              '<(module_root_dir)/lib/libxml2.so',
+              '<(module_root_dir)/lib/liborc-0.4.so',
+              # Ensure runtime linking is relative to sharp.node
+              '-Wl,-rpath=\'$${ORIGIN}/../../lib\''
+            ]
+          }]
+        ]
+      }]
    ],
    'cflags_cc': [
      '-std=c++0x',
@@ -69,28 +115,77 @@
      '-O3'
    ],
    'xcode_settings': {
+      'CLANG_CXX_LANGUAGE_STANDARD': 'c++11',
+      'CLANG_CXX_LIBRARY': 'libc++',
+      'MACOSX_DEPLOYMENT_TARGET': '10.7',
      'OTHER_CPLUSPLUSFLAGS': [
-        '-std=c++11',
-        '-stdlib=libc++',
        '-fexceptions',
        '-Wall',
        '-O3'
-      ],
-      'MACOSX_DEPLOYMENT_TARGET': '10.7'
-    },
-    'msvs_settings': {
-      'VCCLCompilerTool': {
-        'ExceptionHandling': 1 # /EHsc
-      }
+      ]
    },
    'configurations': {
      'Release': {
        'msvs_settings': {
          'VCCLCompilerTool': {
-            'ExceptionHandling': 1,
+            'ExceptionHandling': 1
          }
        }
      }
    },
+  }, {
+    'target_name': 'win_copy_dlls',
+    'type': 'none',
+    'dependencies': [
+      'sharp'
+    ],
+    'conditions': [
+      ['OS == "win"', {
+        # Windows lacks support for rpath
+        'copies': [{
+          'destination': '<(module_root_dir)/build/Release',
+          'files': [
+            '<(module_root_dir)/lib/GNU.Gettext.dll',
+            '<(module_root_dir)/lib/libMagickCore-6.Q16-2.dll',
+            '<(module_root_dir)/lib/libMagickWand-6.Q16-2.dll',
+            '<(module_root_dir)/lib/libasprintf-0.dll',
+            '<(module_root_dir)/lib/libcairo-2.dll',
+            '<(module_root_dir)/lib/libcairo-gobject-2.dll',
+            '<(module_root_dir)/lib/libcairo-script-interpreter-2.dll',
+            '<(module_root_dir)/lib/libexif-12.dll',
+            '<(module_root_dir)/lib/libexpat-1.dll',
+            '<(module_root_dir)/lib/libffi-6.dll',
+            '<(module_root_dir)/lib/libfftw3-3.dll',
+            '<(module_root_dir)/lib/libfontconfig-1.dll',
+            '<(module_root_dir)/lib/libfreetype-6.dll',
+            '<(module_root_dir)/lib/libgcc_s_seh-1.dll',
+            '<(module_root_dir)/lib/libgdk_pixbuf-2.0-0.dll',
+            '<(module_root_dir)/lib/libgio-2.0-0.dll',
+            '<(module_root_dir)/lib/libglib-2.0-0.dll',
+            '<(module_root_dir)/lib/libgmodule-2.0-0.dll',
+            '<(module_root_dir)/lib/libgobject-2.0-0.dll',
+            '<(module_root_dir)/lib/libgsf-1-114.dll',
+            '<(module_root_dir)/lib/libgthread-2.0-0.dll',
+            '<(module_root_dir)/lib/libintl-8.dll',
+            '<(module_root_dir)/lib/libjpeg-62.dll',
+            '<(module_root_dir)/lib/liblcms2-2.dll',
+            '<(module_root_dir)/lib/libopenjpeg-1.dll',
+            '<(module_root_dir)/lib/libopenslide-0.dll',
+            '<(module_root_dir)/lib/libpango-1.0-0.dll',
+            '<(module_root_dir)/lib/libpangocairo-1.0-0.dll',
+            '<(module_root_dir)/lib/libpangowin32-1.0-0.dll',
+            '<(module_root_dir)/lib/libpixman-1-0.dll',
+            '<(module_root_dir)/lib/libpng16-16.dll',
+            '<(module_root_dir)/lib/libquadmath-0.dll',
+            '<(module_root_dir)/lib/libsqlite3-0.dll',
+            '<(module_root_dir)/lib/libssp-0.dll',
+            '<(module_root_dir)/lib/libtiff-5.dll',
+            '<(module_root_dir)/lib/libvips-42.dll',
+            '<(module_root_dir)/lib/libxml2-2.dll',
+            '<(module_root_dir)/lib/zlib1.dll'
+          ]
+        }]
+      }]
+    ]
  }]
 }
--- a/binding.js
+++ b/binding.js
@@ -0,0 +1,111 @@
+'use strict';
+
+var fs = require('fs');
+var path = require('path');
+var zlib = require('zlib');
+
+var semver = require('semver');
+var request = require('request');
+var tar = require('tar');
+
+var tmp = require('os').tmpdir();
+
+var distBaseUrl = 'https://dl.bintray.com/lovell/sharp/';
+
+var vipsHeaderPath = path.join(__dirname, 'include', 'vips', 'vips.h');
+
+// -- Helpers
+
+// Does this file exist?
+var isFile = function(file) {
+  var exists = false;
+  try {
+    exists = fs.statSync(file).isFile();
+  } catch (err) {}
+  return exists;
+};
+
+var unpack = function(tarPath) {
+  var extractor = tar.Extract({
+    path: __dirname
+  });
+  extractor.on('error', error);
+  extractor.on('end', function() {
+    if (!isFile(vipsHeaderPath)) {
+      error('Could not unpack ' + tarPath);
+    }
+  });
+  fs.createReadStream(tarPath).on('error', error)
+    .pipe(zlib.Unzip())
+    .pipe(extractor);
+};
+
+// Error
+var error = function(msg) {
+  if (msg instanceof Error) {
+    msg = msg.message;
+  }
+  process.stderr.write('ERROR: ' + msg + '\n');
+  process.exit(1);
+};
+
+// -- Binary downloaders
+
+module.exports.download_vips = function() {
+  // Has vips been installed locally?
+  if (!isFile(vipsHeaderPath)) {
+    // Ensure 64-bit
+    if (process.arch !== 'x64') {
+      error('ARM and 32-bit systems require manual installation - please see http://sharp.dimens.io/en/stable/install/');
+    }
+    // Ensure libc >= 2.15
+    var lddVersion = process.env.LDD_VERSION;
+    if (lddVersion) {
+      var libcVersion = lddVersion ? lddVersion.split(/\n/)[0].split(' ').slice(-1)[0].trim() : '';
+      if (libcVersion && semver.lt(libcVersion + '.0', '2.13.0')) {
+        error('libc version ' + libcVersion + ' requires manual installation - please see http://sharp.dimens.io/en/stable/install/');
+      }
+    }
+    // Platform-specific .tar.gz
+    var tarFilename = ['libvips', process.env.npm_package_config_libvips, process.platform.substr(0, 3)].join('-') + '.tar.gz';
+    var tarPath = path.join(__dirname, 'packaging', tarFilename);
+    if (isFile(tarPath)) {
+      unpack(tarPath);
+    } else {
+      // Download
+      tarPath = path.join(tmp, tarFilename);
+      var tmpFile = fs.createWriteStream(tarPath).on('finish', function() {
+        unpack(tarPath);
+      });
+      request(distBaseUrl + tarFilename).on('response', function(response) {
+        if (response.statusCode !== 200) {
+          error(distBaseUrl + tarFilename + ' status code ' + response.statusCode);
+        }
+      }).on('error', function(err) {
+        error('Download from ' + distBaseUrl + tarFilename + ' failed: ' + err.message);
+      }).pipe(tmpFile);
+    }
+  }
+};
+
+module.exports.use_global_vips = function() {
+  var useGlobalVips = false;
+  var globalVipsVersion = process.env.GLOBAL_VIPS_VERSION;
+  if (globalVipsVersion) {
+    useGlobalVips = semver.gte(
+      globalVipsVersion,
+      process.env.npm_package_config_libvips
+    );
+  }
+  if (process.platform === 'darwin' && !useGlobalVips) {
+    if (globalVipsVersion) {
+      error(
+        'Found libvips ' + globalVipsVersion + ' but require ' + process.env.npm_package_config_libvips +
+        '\nPlease upgrade libvips by running: brew update && brew upgrade'
+      );
+    } else {
+      error('Please install libvips by running: brew install homebrew/science/vips --with-webp --with-graphicsmagick');
+    }
+  }
+  process.stdout.write(useGlobalVips ? 'true' : 'false');
+};
--- a/circle.yml
+++ b/circle.yml
@@ -0,0 +1,6 @@
+machine:
+  services:
+    - docker
+test:
+  override:
+    - ./packaging/test.sh
--- a/docs/api.md
+++ b/docs/api.md
@@ -78,7 +78,7 @@ to share a single input Stream.
 ```javascript
 var pipeline = sharp().rotate();
 pipeline.clone().resize(800, 600).pipe(firstWritableStream);
-pipeline.clone().extract(20, 20, 100, 100).pipe(secondWritableStream);
+pipeline.clone().extract({ left: 20, top: 20, width: 100, height: 100 }).pipe(secondWritableStream);
 readableStream.pipe(pipeline);
 // firstWritableStream receives auto-rotated, resized readableStream
 // secondWritableStream receives auto-rotated, extracted region of readableStream
@@ -201,14 +201,18 @@ Ignoring the aspect ratio of the input, stretch the image to the exact `width` a

 Use the given interpolator for image resizing, where `interpolator` is an attribute of the `sharp.interpolator` Object e.g. `sharp.interpolator.bicubic`.

+The default interpolator is `bicubic`, providing a general-purpose interpolator that is both fast and of good quality.
+
 Possible interpolators, in order of performance, are:

 * `nearest`: Use [nearest neighbour interpolation](http://en.wikipedia.org/wiki/Nearest-neighbor_interpolation), suitable for image enlargement only.
-* `bilinear`: Use [bilinear interpolation](http://en.wikipedia.org/wiki/Bilinear_interpolation), the default and fastest image reduction interpolation.
-* `bicubic`: Use [bicubic interpolation](http://en.wikipedia.org/wiki/Bicubic_interpolation), which typically reduces performance by 5%.
-* `vertexSplitQuadraticBasisSpline`: Use [VSQBS interpolation](https://github.com/jcupitt/libvips/blob/master/libvips/resample/vsqbs.cpp#L48), which prevents "staircasing" and typically reduces performance by 5%.
-* `locallyBoundedBicubic`: Use [LBB interpolation](https://github.com/jcupitt/libvips/blob/master/libvips/resample/lbb.cpp#L100), which prevents some "[acutance](http://en.wikipedia.org/wiki/Acutance)" and typically reduces performance by a factor of 2.
-* `nohalo`: Use [Nohalo interpolation](http://eprints.soton.ac.uk/268086/), which prevents acutance and typically reduces performance by a factor of 3.
+* `bilinear`: Use [bilinear interpolation](http://en.wikipedia.org/wiki/Bilinear_interpolation), faster than bicubic but with less smooth results.
+* `vertexSplitQuadraticBasisSpline`: Use the smoother [VSQBS interpolation](https://github.com/jcupitt/libvips/blob/master/libvips/resample/vsqbs.cpp#L48) to prevent "staircasing" when enlarging.
+* `bicubic`: Use [bicubic interpolation](http://en.wikipedia.org/wiki/Bicubic_interpolation) (the default).
+* `locallyBoundedBicubic`: Use [LBB interpolation](https://github.com/jcupitt/libvips/blob/master/libvips/resample/lbb.cpp#L100), which prevents some "[acutance](http://en.wikipedia.org/wiki/Acutance)" but typically reduces performance by a factor of 2.
+* `nohalo`: Use [Nohalo interpolation](http://eprints.soton.ac.uk/268086/), which prevents acutance but typically reduces performance by a factor of 3.
+
+[Compare the output of these interpolators](https://github.com/lovell/sharp/tree/master/test/interpolators)

 ```javascript
 sharp(inputBuffer)
@@ -226,11 +230,11 @@ sharp(inputBuffer)

 ### Operations

-#### extract(top, left, width, height)
+#### extract({ left: left, top: top, width: width, height: height })

 Extract a region of the image. Can be used with or without a `resize` operation.

-`top` and `left` are the offset, in pixels, from the top-left corner.
+`left` and `top` are the offset, in pixels, from the top-left corner.

 `width` and `height` are the dimensions of the extracted image.

@@ -238,7 +242,7 @@ Use `extract` before `resize` for pre-resize extraction. Use `extract` after `re

 ```javascript
 sharp(input)
-  .extract(top, left, width, height)
+  .extract({ left: left, top: top, width: width, height: height })
  .toFile(output, function(err) {
    // Extract a region of the input image, saving in the same format.
  });
@@ -246,9 +250,9 @@ sharp(input)

 ```javascript
 sharp(input)
-  .extract(topOffsetPre, leftOffsetPre, widthPre, heightPre)
+  .extract({ left: leftOffsetPre, top: topOffsetPre, width: widthPre, height: heightPre })
  .resize(width, height)
-  .extract(topOffsetPost, leftOffsetPost, widthPost, heightPost)
+  .extract({ left: leftOffsetPost, top: topOffsetPost, width: widthPost, height: heightPost })
  .toFile(output, function(err) {
    // Extract a region, resize, then extract from the resized image
  });
@@ -268,6 +272,10 @@ The default background is `{r: 0, g: 0, b: 0, a: 1}`, black without transparency

 Merge alpha transparency channel, if any, with `background`.

+#### negate()
+
+Produces the "negative" of the image.  White => Black, Black => White, Blue => Yellow, etc.
+
 #### rotate([angle])

 Rotate the output image by either an explicit angle or auto-orient based on the EXIF `Orientation` tag.
@@ -324,6 +332,12 @@ When a `radius` is provided, performs a slower, more accurate sharpen of the L c
 * `flat`, if present, is a Number representing the level of sharpening to apply to "flat" areas, defaulting to a value of 1.0.
 * `jagged`, if present, is a Number representing the level of sharpening to apply to "jagged" areas, defaulting to a value of 2.0.

+#### threshold([threshold])
+
+Converts all pixels in the image to greyscale white or black.  Any pixel greather-than-or-equal-to the threshold (0..255) will be white.  All others will be black.
+
+* `threshold`, if present, is a Number, representing the level above which pixels will be forced to white.
+
 #### gamma([gamma])

 Apply a gamma correction by reducing the encoding (darken) pre-resize at a factor of `1/gamma` then increasing the encoding (brighten) post-resize at a factor of `gamma`.
@@ -555,6 +569,29 @@ sharp.queue.on('change', function(queueLength) {
 });
 ```

+#### versions
+
+An Object containing the version numbers of libvips and, on Linux, its dependencies.
+
+```javascript
+> console.log(sharp.versions);
+
+{ zlib: '1.2.8',
+  ffi: '3.2.1',
+  glib: '2.46.2',
+  xml: '2.9.2',
+  gsf: '1.14.34',
+  exif: '0.6.21',
+  jpeg: '1.4.2',
+  png: '1.6.19',
+  lcms: '2.7',
+  webp: '0.4.4',
+  tiff: '4.0.6',
+  magick: '6.9.2-6',
+  orc: '0.4.24',
+  vips: '8.1.1' }
+```
+
 ### Utilities

 #### sharp.cache([memory], [items])
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -1,5 +1,43 @@
 # Changelog

+### v0.12 - "*look*"
+
+#### v0.12.0 - TBD
+
+* Bundle pre-compiled libvips and its dependencies for 64-bit Linux and Windows.
+  [#42](https://github.com/lovell/sharp/issues/42)
+
+* Take advantage of libvips v8.1.0+ features.
+  [#152](https://github.com/lovell/sharp/issues/152)
+
+* Add support for 64-bit Windows. Drop support for 32-bit Windows.
+  [#224](https://github.com/lovell/sharp/issues/224)
+  [@sabrehagen](https://github.com/sabrehagen)
+
+* Switch default interpolator to bicubic.
+  [#289](https://github.com/lovell/sharp/issues/289)
+  [@mahnunchik](https://github.com/mahnunchik)
+
+* Pre-extract rotatation should not swap width/height.
+  [#296](https://github.com/lovell/sharp/issues/296)
+  [@asilvas](https://github.com/asilvas)
+
+* Ensure 16-bit+alpha input images are (un)premultiplied correctly.
+  [#301](https://github.com/lovell/sharp/issues/301)
+  [@izaakschroeder](https://github.com/izaakschroeder)
+
+* Add `threshold` operation.
+  [#303](https://github.com/lovell/sharp/pull/303)
+  [@dacarley](https://github.com/dacarley)
+
+* Add `negate` operation.
+  [#306](https://github.com/lovell/sharp/pull/306)
+  [@dacarley](https://github.com/dacarley)
+
+* Support `options` Object with existing `extract` operation.
+  [#309](https://github.com/lovell/sharp/pull/309)
+  [@papandreou](https://github.com/papandreou)
+
 ### v0.11 - "*knife*"

 #### v0.11.4 - 5<sup>th</sup> November 2015
--- a/docs/index.md
+++ b/docs/index.md
@@ -7,6 +7,18 @@ smaller, web-friendly JPEG, PNG and WebP images of varying dimensions.
 Resizing an image is typically 4x faster than using
 the quickest ImageMagick and GraphicsMagick settings.

+Colour spaces, embedded ICC profiles and alpha transparency channels are all handled correctly.
+Bicubic interpolation with Lanczos anti-alias filtering ensures quality is not sacrificed for speed.
+
+As well as image resizing, operations such as
+rotation, extraction, compositing and gamma correction are available.
+
+64-bit Windows and recent Linux systems do not require
+the installation of any external runtime dependencies.
+
+Use with OS X is as simple as running `brew install homebrew/science/vips`
+to install the libvips dependency.
+
 [![Test Coverage](https://coveralls.io/repos/lovell/sharp/badge.png?branch=master)](https://coveralls.io/r/lovell/sharp?branch=master)

 ### Formats
@@ -25,14 +37,6 @@ suitable for use with "slippy map" tile viewers like
 [OpenSeadragon](https://github.com/openseadragon/openseadragon)
 and [Leaflet](https://github.com/turban/Leaflet.Zoomify).

-### Features
-
-As well as image resizing, operations such as
-rotation, extraction, compositing and gamma correction are available.
-
-Colour spaces, embedded ICC profiles and alpha transparency channels
-are all handled correctly.
-
 ### Fast

 This module is powered by the blazingly fast
@@ -84,6 +88,7 @@ the help and code contributions of the following people:
 * [Victor Mateevitsi](https://github.com/mvictoras)
 * [Alaric Holloway](https://github.com/skedastik)
 * [Bernhard K. Weisshuhn](https://github.com/bkw)
+* [David A. Carley](https://github.com/dacarley)

 Thank you!

--- a/docs/install.md
+++ b/docs/install.md
@@ -6,75 +6,55 @@ npm install sharp

 ### Prerequisites

-* Node.js v0.10+ or io.js
-* [libvips](https://github.com/jcupitt/libvips) v7.40.0+ (8.1.1+ recommended)
-* C++11 compatible compiler such as gcc 4.6+, clang 3.0+ or MSVC 2013 (Node v4+ requires gcc 4.8+)
+* C++11 compatible compiler such as gcc 4.6+ (Node v4+ requires gcc 4.8+), clang 3.0+ or MSVC 2013
+* [node-gyp](https://github.com/TooTallNate/node-gyp#installation)

 ### Linux

-[![Ubuntu 12.04 Build Status](https://travis-ci.org/lovell/sharp.png?branch=master)](https://travis-ci.org/lovell/sharp)
-[![Centos 6.5 Build Status](https://snap-ci.com/lovell/sharp/branch/master/build_image)](https://snap-ci.com/lovell/sharp/branch/master)
+[![Ubuntu 14.04 Build Status](https://travis-ci.org/lovell/sharp.png?branch=master)](https://travis-ci.org/lovell/sharp)
+[![Linux Build Status](https://circleci.com/gh/lovell/sharp.svg?style=svg&circle-token=6cb6d1d287a51af83722b19ed8885377fbc85e5c)](https://circleci.com/gh/lovell/sharp)

-For a system-wide installation of the most suitable version of
-libvips and its dependencies on the following Operating Systems:
+libvips and its dependencies are fetched and stored within `node_modules/sharp` during `npm install`.
+This involves an automated HTTPS download of approximately 6MB.
+
+Most recent 64-bit Linux-based operating systems should "just work", e.g.:

 * Debian 7, 8
 * Ubuntu 12.04, 14.04, 14.10, 15.04, 15.10
-* Mint 13, 17
-* Elementary 0.3
-* RHEL/Centos/Scientific 6, 7
-* Fedora 21, 22
-* Amazon Linux 2015.03, 2015.09
-* OpenSuse 13
+* Centos 7
+* Fedora 20, 21
+* openSUSE 13.2
+* Archlinux 2015.06.01

-run the following as a user with `sudo` access:
+Preference will be given to an existing globally-installed (via `pkg-config`)
+version of libvips that meets the minimum version requirement.
+This allows the use of newer versions of libvips with older versions of sharp.
+
+For older and 32-bit Linux-based operating systems,
+a system-wide installation of the most suitable version of
+libvips and its dependencies can be achieved by running
+the following command as a user with `sudo` access
+(requires `curl` and `pkg-config`):

 ```sh
 curl -s https://raw.githubusercontent.com/lovell/sharp/master/preinstall.sh | sudo bash -
 ```

-or run the following as `root`:
-
-```sh
-curl -s https://raw.githubusercontent.com/lovell/sharp/master/preinstall.sh | bash -
-```
-
-The [preinstall.sh](https://github.com/lovell/sharp/blob/master/preinstall.sh) script requires `curl` and `pkg-config`.
-
-Add `--with-openslide` to enable OpenSlide support:
-
-```sh
-curl -s https://raw.githubusercontent.com/lovell/sharp/master/preinstall.sh | sudo bash -s -- --with-openslide
-```
-
-#### Ubuntu LTS
-
-libvips v7.40.6 is available via a PPA.
-
-##### 12.04
-
-```sh
-sudo add-apt-repository -y ppa:lovell/precise-backport-vips
-sudo apt-get update
-sudo apt-get install -y libvips-dev libgsf-1-dev
-```
-
-##### 14.04
-
-```sh
-sudo add-apt-repository -y ppa:lovell/trusty-backport-vips
-sudo apt-get update
-sudo apt-get install -y libvips-dev libgsf-1-dev
-```
-
 ### Mac OS

 [![OS X 10.9.5 Build Status](https://travis-ci.org/lovell/sharp-osx-ci.png?branch=master)](https://travis-ci.org/lovell/sharp-osx-ci)

-Install libvips via homebrew:
+libvips must be installed before `npm install` is run.
+This can be achieved via homebrew:

 ```sh
-brew install homebrew/science/vips --with-webp --with-graphicsmagick
+brew install homebrew/science/vips
+```
+
+For GIF input and WebP output suppport use:
+
+```sh
+brew install homebrew/science/vips --with-imagemagick --with-webp
 ```

 A missing or incorrectly configured _Xcode Command Line Tools_ installation
@@ -89,18 +69,13 @@ If so, please try `brew link gettext --force`.

 ### Windows

-[![Windows Server 2012 Build Status](https://ci.appveyor.com/api/projects/status/pgtul704nkhhg6sg)](https://ci.appveyor.com/project/lovell/sharp)
+[![Windows x64 Build Status](https://ci.appveyor.com/api/projects/status/pgtul704nkhhg6sg)](https://ci.appveyor.com/project/lovell/sharp)

-Requires x86 32-bit Node.js or io.js (use `iojs.exe` rather than `node.exe`).
+libvips and its dependencies are fetched and stored within `node_modules\sharp` during `npm install`.
+This involves an automated HTTPS download of approximately 9MB.

-The WebP format is currently unsupported.
-
-1. Ensure the [node-gyp prerequisites](https://github.com/TooTallNate/node-gyp#installation) are met.
-2. [Download](http://www.vips.ecs.soton.ac.uk/supported/current/win32/) and unzip `vips-dev.x.y.z.zip`.
-3. Set the `VIPS_HOME` environment variable to the full path of the `vips-dev-x.y.z` directory.
-4. Add `vips-dev-x.y.z\bin` to `PATH`.
-
-Versions of MSVC more recent than 2013 may require the use of `npm install --arch=ia32 --msvs_version=2013`.
+Only 64-bit (x64) `node.exe` is supported.
+The WebP format is currently unavailable on Windows.

 ### Heroku

@@ -110,13 +85,20 @@ and its dependencies.

 ### Docker

-[Marc Bachmann](https://github.com/marcbachmann) maintains a
-[Dockerfile for libvips](https://github.com/marcbachmann/dockerfile-libvips).
+[Marc Bachmann](https://github.com/marcbachmann) maintains an
+[Ubuntu-based Dockerfile for libvips](https://github.com/marcbachmann/dockerfile-libvips).

 ```sh
 docker pull marcbachmann/libvips
 ```

+[Will Jordan](https://github.com/wjordan) maintains an
+[Alpine-based Dockerfile for libvips](https://github.com/wjordan/dockerfile-libvips).
+
+```sh
+docker pull wjordan/libvips
+```
+
 ### Build tools

 * [gulp-responsive](https://www.npmjs.com/package/gulp-responsive)
--- a/docs/performance.md
+++ b/docs/performance.md
@@ -2,39 +2,40 @@

 ### Test environment

-* AWS EC2 [c4.xlarge](http://aws.amazon.com/ec2/instance-types/#c4)
-* Amazon Linux AMI 2015.09
-* Node.js v4.1.2
+* AWS EC2 [c4.xlarge](http://aws.amazon.com/ec2/instance-types/#c4) (4x E5-2666 v3 @2.90GHz)
+* Amazon Linux 2015.09.1
+* Node.js v5.1.0

 ### The contenders

-* [jimp](https://www.npmjs.com/package/jimp) v0.2.8 - Image processing in pure JavaScript.
+* [jimp](https://www.npmjs.com/package/jimp) v0.2.19 - Image processing in pure JavaScript. Bilinear interpolation only.
 * [lwip](https://www.npmjs.com/package/lwip) v0.0.8 - Wrapper around CImg, compiles dependencies from source.
-* ~~[imagemagick-native](https://www.npmjs.com/package/imagemagick-native)~~ - Wrapper around libmagick++, supports Buffers only. Does not currently work with Node.js v4.
+* [imagemagick-native](https://www.npmjs.com/package/imagemagick-native) @5ab570e - Wrapper around libmagick++, supports Buffers only.
 * [imagemagick](https://www.npmjs.com/package/imagemagick) v0.1.3 - Supports filesystem only and "*has been unmaintained for a long time*".
-* [gm](https://www.npmjs.com/package/gm) v1.20.0 - Fully featured wrapper around GraphicsMagick's `convert` command line utility.
-* sharp v0.11.3 / libvips v8.1.0 - Caching within libvips disabled to ensure a fair comparison.
+* [gm](https://www.npmjs.com/package/gm) v1.21.0 - Fully featured wrapper around GraphicsMagick's `gm` command line utility.
+* sharp v0.12.0 / libvips v8.1.1 - Caching within libvips disabled to ensure a fair comparison.

 ### The task

-Decompress a 2725x2225 JPEG image, resize to 720x480 using bilinear interpolation, then compress to JPEG.
+Decompress a 2725x2225 JPEG image, resize to 720x480 using bicubic interpolation (where available), then compress to JPEG.

 ### Results

-| Module      | Input  | Output | Ops/sec | Speed-up |
-| :---------- | :----- | :----- | ------: | -------: |
-| jimp        | file   | file   |    0.94 |      1.0 |
-| jimp        | buffer | buffer |    1.12 |      1.2 |
-| lwip        | file   | file   |    1.12 |      1.2 |
-| lwip        | buffer | buffer |    1.13 |      1.2 |
-| gm          | buffer | buffer |    5.50 |      5.9 |
-| gm          | file   | file   |    5.55 |      5.9 |
-| imagemagick | file   | file   |    8.66 |      9.2 |
-| sharp       | stream | stream |   16.33 |     17.4 |
-| sharp       | file   | file   |   16.88 |     18.0 |
-| sharp       | file   | buffer |   16.90 |     18.1 |
-| sharp       | buffer | file   |   16.99 |     18.1 |
-| sharp       | buffer | buffer |   17.06 |     18.1 |
+| Module             | Input  | Output | Ops/sec | Speed-up |
+| :----------------- | :----- | :----- | ------: | -------: |
+| jimp               | file   | file   |    0.99 |      1.0 |
+| jimp               | buffer | buffer |    1.05 |      1.1 |
+| lwip               | file   | file   |    1.13 |      1.1 |
+| lwip               | buffer | buffer |    1.13 |      1.1 |
+| imagemagick-native | buffer | buffer |    1.67 |      1.7 |
+| imagemagick        | file   | file   |    5.19 |      5.2 |
+| gm                 | buffer | buffer |    5.56 |      5.6 |
+| gm                 | file   | file   |    5.59 |      5.6 |
+| sharp              | stream | stream |   21.91 |     22.1 |
+| sharp              | file   | file   |   22.79 |     23.0 |
+| sharp              | file   | buffer |   22.91 |     23.1 |
+| sharp              | buffer | file   |   23.03 |     23.3 |
+| sharp              | buffer | buffer |   23.15 |     23.4 |

 Greater performance can be expected with caching enabled (default) and using 8+ core machines.

@@ -50,7 +51,11 @@ brew install graphicsmagick
 ```

 ```sh
-sudo apt-get install imagemagick graphicsmagick libmagick++-dev
+sudo apt-get install imagemagick libmagick++-dev graphicsmagick
+```
+
+```sh
+sudo yum install ImageMagick-devel ImageMagick-c++-devel GraphicsMagick
 ```

 ### Running the benchmark test
--- a/index.js
+++ b/index.js
@@ -10,14 +10,31 @@ var color = require('color');
 var BluebirdPromise = require('bluebird');

 var sharp = require('./build/Release/sharp');
-var libvipsVersion = sharp.libvipsVersion();

+// Versioning
+var versions = {
+  vips: sharp.libvipsVersion()
+};
+(function() {
+  // Does libvips meet minimum requirement?
+  var libvipsVersionMin = require('./package.json').config.libvips;
+  if (semver.lt(versions.vips, libvipsVersionMin)) {
+    throw new Error('Found libvips ' + versions.vips + ' but require at least ' + libvipsVersionMin);
+  }
+  // Include versions of dependencies, if present
+  try {
+    versions = require('./lib/versions.json');
+  } catch (err) {}
+})();
+
+// Limits
 var maximum = {
  width: 0x3FFF,
  height: 0x3FFF,
  pixels: Math.pow(0x3FFF, 2)
 };

+// Constructor-factory
 var Sharp = function(input) {
  if (!(this instanceof Sharp)) {
    return new Sharp(input);
@@ -49,14 +66,16 @@ var Sharp = function(input) {
    flip: false,
    flop: false,
    withoutEnlargement: false,
-    interpolator: 'bilinear',
+    interpolator: 'bicubic',
    // operations
    background: [0, 0, 0, 255],
    flatten: false,
+    negate: false,
    blurSigma: 0,
    sharpenRadius: 0,
    sharpenFlat: 1,
    sharpenJagged: 2,
+    threshold: 0,
    gamma: 0,
    greyscale: false,
    normalize: 0,
@@ -109,6 +128,11 @@ module.exports.queue = new events.EventEmitter();
 */
 module.exports.format = sharp.format();

+/*
+  Version numbers of libvips and its dependencies
+*/
+module.exports.versions = versions;
+
 /*
  Handle incoming chunk on Writable Stream
 */
@@ -137,7 +161,18 @@ Sharp.prototype._write = function(chunk, encoding, callback) {
 };

 // Crop this part of the resized image (Center/Centre, North, East, South, West)
-module.exports.gravity = {'center': 0, 'centre': 0, 'north': 1, 'east': 2, 'south': 3, 'west': 4, 'northeast': 5, 'southeast': 6, 'southwest': 7, 'northwest': 8};
+module.exports.gravity = {
+  'center': 0,
+  'centre': 0,
+  'north': 1,
+  'east': 2,
+  'south': 3,
+  'west': 4,
+  'northeast': 5,
+  'southeast': 6,
+  'southwest': 7,
+  'northwest': 8
+};

 Sharp.prototype.crop = function(gravity) {
  this.options.canvas = 'crop';
@@ -151,17 +186,25 @@ Sharp.prototype.crop = function(gravity) {
  return this;
 };

-Sharp.prototype.extract = function(topOffset, leftOffset, width, height) {
-  /*jslint unused: false */
+Sharp.prototype.extract = function(options) {
+  if (!options || typeof options !== 'object') {
+    // Legacy extract(top,left,width,height) syntax
+    options = {
+      left: arguments[1],
+      top: arguments[0],
+      width: arguments[2],
+      height: arguments[3]
+    };
+  }
  var suffix = this.options.width === -1 && this.options.height === -1 ? 'Pre' : 'Post';
-  var values = arguments;
-  ['topOffset', 'leftOffset', 'width', 'height'].forEach(function(name, index) {
-    if (typeof values[index] === 'number' && !Number.isNaN(values[index]) && (values[index] % 1 === 0) && values[index] >= 0) {
-      this.options[name + suffix] = values[index];
+  ['left', 'top', 'width', 'height'].forEach(function (name) {
+    var value = options[name];
+    if (typeof value === 'number' && !Number.isNaN(value) && value % 1 === 0 && value >= 0) {
+      this.options[name + (name === 'left' || name === 'top' ? 'Offset' : '') + suffix] = value;
    } else {
-      throw new Error('Non-integer value for ' + name + ' of ' + values[index]);
+      throw new Error('Non-integer value for ' + name + ' of ' + value);
    }
-  }.bind(this));
+  }, this);
  // Ensure existing rotation occurs before pre-resize extraction
  if (suffix === 'Pre' && this.options.angle !== 0) {
    this.options.rotateBeforePreExtract = true;
@@ -210,6 +253,11 @@ Sharp.prototype.flatten = function(flatten) {
  return this;
 };

+Sharp.prototype.negate = function(negate) {
+  this.options.negate = (typeof negate === 'boolean') ? negate : true;
+  return this;
+};
+
 Sharp.prototype.overlayWith = function(overlayPath) {
  if (typeof overlayPath !== 'string') {
    throw new Error('The overlay path must be a string');
@@ -323,6 +371,19 @@ Sharp.prototype.sharpen = function(radius, flat, jagged) {
  return this;
 };

+Sharp.prototype.threshold = function(threshold) {
+  if (typeof threshold === 'undefined') {
+    this.options.threshold = 128;
+  } else if (typeof threshold === 'boolean') {
+    this.options.threshold = threshold ? 128 : 0;
+  } else if (typeof threshold === 'number' && !Number.isNaN(threshold) && (threshold % 1 === 0) && threshold >= 0 && threshold <= 255) {
+    this.options.threshold = threshold;
+  } else {
+    throw new Error('Invalid threshold (0 to 255) ' + threshold);
+  }
+  return this;
+};
+
 /*
  Set the interpolator to use for the affine transformation
 */
@@ -370,11 +431,7 @@ Sharp.prototype.gamma = function(gamma) {
  Enhance output image contrast by stretching its luminance to cover the full dynamic range
 */
 Sharp.prototype.normalize = function(normalize) {
-  if (process.platform !== 'win32') {
-    this.options.normalize = (typeof normalize === 'boolean') ? normalize : true;
-  } else {
-    console.error('normalize unavailable on win32 platform');
-  }
+  this.options.normalize = (typeof normalize === 'boolean') ? normalize : true;
  return this;
 };
 Sharp.prototype.normalise = Sharp.prototype.normalize;
@@ -420,14 +477,10 @@ Sharp.prototype.compressionLevel = function(compressionLevel) {
 };

 /*
-  Disable the use of adaptive row filtering for PNG output - requires libvips 7.42.0+
+  Disable the use of adaptive row filtering for PNG output
 */
 Sharp.prototype.withoutAdaptiveFiltering = function(withoutAdaptiveFiltering) {
-  if (semver.gte(libvipsVersion, '7.42.0')) {
-    this.options.withoutAdaptiveFiltering = (typeof withoutAdaptiveFiltering === 'boolean') ? withoutAdaptiveFiltering : true;
-  } else {
-    console.error('withoutAdaptiveFiltering requires libvips 7.41.0+');
-  }
+  this.options.withoutAdaptiveFiltering = (typeof withoutAdaptiveFiltering === 'boolean') ? withoutAdaptiveFiltering : true;
  return this;
 };

@@ -440,41 +493,29 @@ Sharp.prototype.withoutChromaSubsampling = function(withoutChromaSubsampling) {
 };

 /*
-  Apply trellis quantisation to JPEG output - requires libvips 8.0.0+ compiled against mozjpeg 3.0+
+  Apply trellis quantisation to JPEG output - requires mozjpeg 3.0+
 */
 Sharp.prototype.trellisQuantisation = function(trellisQuantisation) {
-  if (semver.gte(libvipsVersion, '8.0.0')) {
-    this.options.trellisQuantisation = (typeof trellisQuantisation === 'boolean') ? trellisQuantisation : true;
-  } else {
-    console.error('trellisQuantisation requires libvips 8.0.0+');
-  }
+  this.options.trellisQuantisation = (typeof trellisQuantisation === 'boolean') ? trellisQuantisation : true;
  return this;
 };
 Sharp.prototype.trellisQuantization = Sharp.prototype.trellisQuantisation;

 /*
-  Apply overshoot deringing to JPEG output - requires libvips 8.0.0+ compiled against mozjpeg 3.0+
+  Apply overshoot deringing to JPEG output - requires mozjpeg 3.0+
 */
 Sharp.prototype.overshootDeringing = function(overshootDeringing) {
-  if (semver.gte(libvipsVersion, '8.0.0')) {
-    this.options.overshootDeringing = (typeof overshootDeringing === 'boolean') ? overshootDeringing : true;
-  } else {
-    console.error('overshootDeringing requires libvips 8.0.0+');
-  }
+  this.options.overshootDeringing = (typeof overshootDeringing === 'boolean') ? overshootDeringing : true;
  return this;
 };

 /*
-  Optimise scans in progressive JPEG output - requires libvips 8.0.0+ compiled against mozjpeg 3.0+
+  Optimise scans in progressive JPEG output - requires mozjpeg 3.0+
 */
 Sharp.prototype.optimiseScans = function(optimiseScans) {
-  if (semver.gte(libvipsVersion, '8.0.0')) {
-    this.options.optimiseScans = (typeof optimiseScans === 'boolean') ? optimiseScans : true;
-    if (this.options.optimiseScans) {
-      this.progressive();
-    }
-  } else {
-    console.error('optimiseScans requires libvips 8.0.0+');
+  this.options.optimiseScans = (typeof optimiseScans === 'boolean') ? optimiseScans : true;
+  if (this.options.optimiseScans) {
+    this.progressive();
  }
  return this;
 };
@@ -493,7 +534,7 @@ Sharp.prototype.withMetadata = function(withMetadata) {
        typeof withMetadata.orientation === 'number' &&
        !Number.isNaN(withMetadata.orientation) &&
        withMetadata.orientation % 1 === 0 &&
-        withMetadata.orientation >=0 &&
+        withMetadata.orientation >= 0 &&
        withMetadata.orientation <= 7
      ) {
        this.options.withMetadataOrientation = withMetadata.orientation;
@@ -519,7 +560,7 @@ Sharp.prototype.tile = function(size, overlap) {
  }
  // Overlap of tiles, in pixels
  if (typeof overlap !== 'undefined' && overlap !== null) {
-    if (!Number.isNaN(overlap) && overlap % 1 === 0 && overlap >=0 && overlap <= 8192) {
+    if (!Number.isNaN(overlap) && overlap % 1 === 0 && overlap >= 0 && overlap <= 8192) {
      if (overlap > this.options.tileSize) {
        throw new Error('Tile overlap ' + overlap + ' cannot be larger than tile size ' + this.options.tileSize);
      }
@@ -628,12 +669,7 @@ Sharp.prototype.webp = function() {
  Force raw, uint8 output
 */
 Sharp.prototype.raw = function() {
-  var supportsRawOutput = module.exports.format.raw.output;
-  if (supportsRawOutput.file || supportsRawOutput.buffer || supportsRawOutput.stream) {
-    this.options.output = '__raw';
-  } else {
-    console.error('Raw output requires libvips 7.42.0+');
-  }
+  this.options.output = '__raw';
  return this;
 };

@@ -827,10 +863,3 @@ module.exports.concurrency = function(concurrency) {
 module.exports.counters = function() {
  return sharp.counters();
 };
-
-/*
-  Get the version of the libvips library
-*/
-module.exports.libvipsVersion = function() {
-  return libvipsVersion;
-};
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
  "name": "sharp",
-  "version": "0.11.4",
+  "version": "0.12.0",
  "author": "Lovell Fuller <npm@lovell.info>",
  "contributors": [
    "Pierre Inglebert <pierre.inglebert@gmail.com>",
@@ -17,16 +17,17 @@
    "Victor Mateevitsi <mvictoras@gmail.com>",
    "Alaric Holloway <alaric.holloway@gmail.com>",
    "Bernhard K. Weisshuhn <bkw@codingforce.com>",
-    "Chris Riley <criley@primedia.com>"
+    "Chris Riley <criley@primedia.com>",
+    "David Carley <dacarley@gmail.com>"
  ],
  "description": "High performance Node.js module to resize JPEG, PNG, WebP and TIFF images using the libvips library",
  "scripts": {
-    "clean": "rm -rf test/fixtures/output.*",
-    "test": "VIPS_WARNING=0 node ./node_modules/istanbul/lib/cli.js cover ./node_modules/mocha/bin/_mocha -- --slow=5000 --timeout=20000 ./test/unit/*.js",
-    "test-clean": "npm run clean && npm install && npm test",
+    "clean": "rm -rf node_modules/ build/ include/ lib/ coverage/ test/fixtures/output.*",
+    "test": "VIPS_WARNING=0 node ./node_modules/istanbul/lib/cli.js cover ./node_modules/mocha/bin/_mocha -- --slow=5000 --timeout=30000 ./test/unit/*.js",
+    "test-win": "node ./node_modules/mocha/bin/mocha --slow=5000 --timeout=30000 ./test/unit/*.js",
    "test-leak": "./test/leak/leak.sh",
-    "test-win32-node": "node ./node_modules/mocha/bin/mocha --slow=5000 --timeout=30000 ./test/unit/*.js",
-    "test-win32-iojs": "iojs ./node_modules/mocha/bin/mocha --slow=5000 --timeout=30000 ./test/unit/*.js"
+    "test-packaging": "./packaging/test.sh",
+    "test-clean": "rm -rf coverage/ test/fixtures/output.* && npm install && npm test"
  },
  "main": "index.js",
  "repository": {
@@ -49,21 +50,26 @@
    "bluebird": "^3.0.5",
    "color": "^0.10.1",
    "nan": "^2.1.0",
-    "semver": "^5.0.3"
+    "semver": "^5.1.0",
+    "request": "^2.67.0",
+    "tar": "^2.2.1"
  },
  "devDependencies": {
    "async": "^1.5.0",
    "coveralls": "^2.11.4",
-    "exif-reader": "1.0.0",
+    "exif-reader": "^1.0.0",
    "icc": "^0.0.2",
    "istanbul": "^0.4.0",
-    "mocha": "^2.3.3",
+    "mocha": "^2.3.4",
    "mocha-jshint": "^2.2.5",
    "node-cpplint": "^0.4.0",
-    "rimraf": "^2.4.3",
+    "rimraf": "^2.4.4",
    "bufferutil": "^1.2.1"
  },
  "license": "Apache-2.0",
+  "config": {
+    "libvips": "8.1.1"
+  },
  "engines": {
    "node": ">=0.10"
  }
--- a/packaging/build.sh
+++ b/packaging/build.sh
@@ -0,0 +1,28 @@
+#!/bin/sh
+
+# Is docker available?
+
+if ! type docker >/dev/null; then
+  echo "Please install docker"
+  exit 1
+fi
+
+# TODO: docker v1.9.0 will allow build-time args - https://github.com/docker/docker/pull/15182
+
+# Windows
+
+docker build -t vips-dev-win win
+WIN_CONTAINER_ID=$(docker run -d vips-dev-win)
+docker cp $WIN_CONTAINER_ID:/libvips-8.1.1-win.tar.gz .
+docker rm $WIN_CONTAINER_ID
+
+# Linux
+
+docker build -t vips-dev-lin lin
+LIN_CONTAINER_ID=$(docker run -d vips-dev-lin)
+docker cp $LIN_CONTAINER_ID:/libvips-8.1.1-lin.tar.gz .
+docker rm $LIN_CONTAINER_ID
+
+# Checksums
+
+sha256sum *.tar.gz
--- a/packaging/lin/Dockerfile
+++ b/packaging/lin/Dockerfile
@@ -0,0 +1,137 @@
+FROM debian:wheezy
+MAINTAINER Lovell Fuller <npm@lovell.info>
+
+# Build dependencies
+RUN apt-get update && apt-get install -y build-essential autoconf libtool nasm gtk-doc-tools texinfo
+
+# Working directories
+ENV DEPS /deps
+ENV TARGET /target
+RUN mkdir ${DEPS} && mkdir ${TARGET}
+
+# Common build paths and flags
+ENV PKG_CONFIG_PATH ${PKG_CONFIG_PATH}:${TARGET}/lib/pkgconfig
+ENV PATH ${PATH}:${TARGET}/bin
+ENV CPPFLAGS -I${TARGET}/include
+ENV LDFLAGS -L${TARGET}/lib
+
+# Dependency version numbers
+ENV VERSION_ZLIB 1.2.8
+ENV VERSION_FFI 3.2.1
+ENV VERSION_GLIB 2.46.2
+ENV VERSION_XML2 2.9.2
+ENV VERSION_GSF 1.14.34
+ENV VERSION_EXIF 0.6.21
+ENV VERSION_JPEG 1.4.2
+ENV VERSION_PNG16 1.6.19
+ENV VERSION_LCMS2 2.7
+ENV VERSION_WEBP 0.4.4
+ENV VERSION_TIFF 4.0.6
+ENV VERSION_MAGICK 6.9.2-6
+ENV VERSION_ORC 0.4.24
+ENV VERSION_VIPS 8.1.1
+
+RUN mkdir ${DEPS}/zlib
+RUN curl -Ls http://zlib.net/zlib-${VERSION_ZLIB}.tar.xz | tar xJC ${DEPS}/zlib --strip-components=1
+WORKDIR ${DEPS}/zlib
+RUN ./configure --prefix=${TARGET} && make install
+RUN rm ${TARGET}/lib/libz.a
+
+RUN mkdir ${DEPS}/ffi
+RUN curl -Ls ftp://sourceware.org/pub/libffi/libffi-${VERSION_FFI}.tar.gz | tar xzC ${DEPS}/ffi --strip-components=1
+WORKDIR ${DEPS}/ffi
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking --disable-builddir && make install-strip
+
+RUN mkdir ${DEPS}/glib
+RUN curl -Ls http://ftp.gnome.org/pub/gnome/sources/glib/2.46/glib-${VERSION_GLIB}.tar.xz | tar xJC ${DEPS}/glib --strip-components=1
+WORKDIR ${DEPS}/glib
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking && make install-strip
+
+RUN mkdir ${DEPS}/xml2
+RUN curl -Ls http://xmlsoft.org/sources/libxml2-${VERSION_XML2}.tar.gz | tar xzC ${DEPS}/xml2 --strip-components=1
+WORKDIR ${DEPS}/xml2
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking --without-python --with-zlib=${TARGET} && make install-strip
+
+RUN mkdir ${DEPS}/gsf
+RUN curl -Ls http://ftp.gnome.org/pub/GNOME/sources/libgsf/1.14/libgsf-${VERSION_GSF}.tar.xz | tar xJC ${DEPS}/gsf --strip-components=1
+WORKDIR ${DEPS}/gsf
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking && make install-strip
+
+RUN mkdir ${DEPS}/exif
+RUN curl -Ls http://kent.dl.sourceforge.net/project/libexif/libexif/${VERSION_EXIF}/libexif-${VERSION_EXIF}.tar.bz2 | tar xjC ${DEPS}/exif --strip-components=1
+WORKDIR ${DEPS}/exif
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking && make install-strip
+
+RUN mkdir ${DEPS}/jpeg
+RUN curl -Ls http://kent.dl.sourceforge.net/project/libjpeg-turbo/${VERSION_JPEG}/libjpeg-turbo-${VERSION_JPEG}.tar.gz | tar xzC ${DEPS}/jpeg --strip-components=1
+WORKDIR ${DEPS}/jpeg
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking --with-jpeg8 --without-turbojpeg && make install-strip
+
+RUN mkdir ${DEPS}/png16
+RUN curl -Ls http://kent.dl.sourceforge.net/project/libpng/libpng16/${VERSION_PNG16}/libpng-${VERSION_PNG16}.tar.xz | tar xJC ${DEPS}/png16 --strip-components=1
+WORKDIR ${DEPS}/png16
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking && make install-strip
+
+RUN mkdir ${DEPS}/lcms2
+RUN curl -Ls http://kent.dl.sourceforge.net/project/lcms/lcms/${VERSION_LCMS2}/lcms2-${VERSION_LCMS2}.tar.gz | tar xzC ${DEPS}/lcms2 --strip-components=1
+WORKDIR ${DEPS}/lcms2
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking && make install-strip
+
+RUN mkdir ${DEPS}/webp
+RUN curl -Ls http://downloads.webmproject.org/releases/webp/libwebp-${VERSION_WEBP}.tar.gz | tar xzC ${DEPS}/webp --strip-components=1
+WORKDIR ${DEPS}/webp
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking && make install-strip
+
+RUN mkdir ${DEPS}/tiff
+RUN curl -Ls http://download.osgeo.org/libtiff/tiff-${VERSION_TIFF}.tar.gz /deps/tiff.tar.gz | tar xzC ${DEPS}/tiff --strip-components=1
+WORKDIR ${DEPS}/tiff
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking && make install-strip
+RUN rm ${TARGET}/lib/libtiffxx*
+
+RUN mkdir ${DEPS}/magick
+RUN curl -Ls http://www.imagemagick.org/download/releases/ImageMagick-${VERSION_MAGICK}.tar.xz | tar xJC ${DEPS}/magick --strip-components=1
+WORKDIR ${DEPS}/magick
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking --without-magick-plus-plus && make install-strip
+
+RUN mkdir ${DEPS}/orc
+RUN curl -Ls http://gstreamer.freedesktop.org/data/src/orc/orc-${VERSION_ORC}.tar.xz | tar xJC ${DEPS}/orc --strip-components=1
+WORKDIR ${DEPS}/orc
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking && make install-strip
+
+RUN mkdir ${DEPS}/vips
+RUN curl -Ls http://www.vips.ecs.soton.ac.uk/supported/8.1/vips-${VERSION_VIPS}.tar.gz | tar xzC ${DEPS}/vips --strip-components=1
+WORKDIR ${DEPS}/vips
+RUN ./configure --prefix=${TARGET} --enable-shared --disable-static --disable-dependency-tracking \
+  --disable-debug --disable-introspection --without-python --without-fftw \
+  --with-zip-includes=${TARGET}/include --with-zip-libraries=${TARGET}/lib \
+  --with-jpeg-includes=${TARGET}/include --with-jpeg-libraries=${TARGET}/lib \
+  && make install-strip
+
+# Remove the C++ bindings
+WORKDIR ${TARGET}/include
+RUN rm -rf vips/vipsc++.h vips/vipscpp.h vips/V*.h
+WORKDIR ${TARGET}/lib
+RUN rm -rf pkgconfig .libs *.la libvipsCC* libvips-cpp.*
+
+# Create JSON file of version numbers
+WORKDIR ${TARGET}
+RUN echo "{\n\
+  \"zlib\": \"${VERSION_ZLIB}\",\n\
+  \"ffi\": \"${VERSION_FFI}\",\n\
+  \"glib\": \"${VERSION_GLIB}\",\n\
+  \"xml\": \"${VERSION_XML2}\",\n\
+  \"gsf\": \"${VERSION_GSF}\",\n\
+  \"exif\": \"${VERSION_EXIF}\",\n\
+  \"jpeg\": \"${VERSION_JPEG}\",\n\
+  \"png\": \"${VERSION_PNG16}\",\n\
+  \"lcms\": \"${VERSION_LCMS2}\",\n\
+  \"webp\": \"${VERSION_WEBP}\",\n\
+  \"tiff\": \"${VERSION_TIFF}\",\n\
+  \"magick\": \"${VERSION_MAGICK}\",\n\
+  \"orc\": \"${VERSION_ORC}\",\n\
+  \"vips\": \"${VERSION_VIPS}\"\n\
+}" >lib/versions.json
+
+# Create .tar.gz
+WORKDIR ${TARGET}
+RUN GZIP=-9 tar czf /libvips-${VERSION_VIPS}-lin.tar.gz include lib
--- a/packaging/test.sh
+++ b/packaging/test.sh
@@ -0,0 +1,50 @@
+#!/bin/sh
+
+# Verify docker is available
+if ! type docker >/dev/null; then
+  echo "Please install docker"
+  exit 1
+fi
+
+test="npm run clean; NODE_ENV=development npm install --unsafe-perm; npm test"
+
+# Debian 7, 8
+# Ubuntu 12.04, 14.04
+for dist in wheezy jessie precise trusty; do
+  echo "Testing $dist..."
+  if docker run -i -t --rm -v $PWD:/v nodesource/$dist:0.12 >packaging/$dist.log 2>&1 sh -c "cd /v; ./packaging/test/debian.sh; $test";
+  then echo "$dist OK"
+  else echo "$dist fail" && cat packaging/$dist.log
+  fi
+done
+
+# Centos 6
+echo "Testing centos6..."
+if docker run -i -t --rm -v $PWD:/v nodesource/centos6:0.12 >packaging/centos6.log 2>&1 sh -c "cd /v; source ./packaging/test/centos6.sh; ./preinstall.sh; $test";
+then echo "centos6 OK"
+else echo "centos6 fail" && cat packaging/centos6.log
+fi
+
+# Centos 7
+# Fedora 20, 21
+for dist in centos7 fedora20 fedora21; do
+  echo "Testing $dist..."
+  if docker run -i -t --rm -v $PWD:/v nodesource/$dist:0.12 >packaging/$dist.log 2>&1 sh -c "cd /v; $test";
+  then echo "$dist OK"
+  else echo "$dist fail" && cat packaging/$dist.log
+  fi
+done
+
+# openSUSE 13.2
+echo "Testing opensuse..."
+if docker run -i -t --rm -v $PWD:/v opensuse:13.2 >packaging/opensuse.log 2>&1 /bin/sh -c "cd /v; ./packaging/test/opensuse.sh; $test";
+then echo "opensuse OK"
+else echo "opensuse fail" && cat packaging/opensuse.log
+fi
+
+# Archlinux 2015.06.01
+echo "Testing archlinux..."
+if docker run -i -t --rm -v $PWD:/v base/archlinux:2015.06.01 >packaging/archlinux.log 2>&1 sh -c "cd /v; ./packaging/test/archlinux.sh; $test";
+then echo "archlinux OK"
+else echo "archlinux fail" && cat packaging/archlinux.log
+fi
--- a/packaging/test/archlinux.sh
+++ b/packaging/test/archlinux.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+
+# Install Node.js on Archlinux
+pacman -Sy --noconfirm gcc make python2 nodejs npm | cat
+ln -s /usr/bin/python2 /usr/bin/python
--- a/packaging/test/centos6.sh
+++ b/packaging/test/centos6.sh
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+# Install C++11 compatible version of g++ on Centos 6
+curl -o /etc/yum.repos.d/devtools-1.1.repo http://people.centos.org/tru/devtools-1.1/devtools-1.1.repo
+yum install -y devtoolset-1.1
+export CC=/opt/centos/devtoolset-1.1/root/usr/bin/gcc
+export CPP=/opt/centos/devtoolset-1.1/root/usr/bin/cpp
+export CXX=/opt/centos/devtoolset-1.1/root/usr/bin/c++
--- a/packaging/test/debian.sh
+++ b/packaging/test/debian.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+
+# Install pkg-config on Debian/Ubuntu
+apt-get update
+apt-get install -y pkg-config
--- a/packaging/test/opensuse.sh
+++ b/packaging/test/opensuse.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+# Install Node.js on openSUSE 13.2
+zypper addrepo http://download.opensuse.org/repositories/devel:languages:nodejs/openSUSE_13.2/devel:languages:nodejs.repo
+zypper --gpg-auto-import-keys refresh
+zypper --non-interactive install gcc-c++ make nodejs-devel nodejs-npm
+npm install -g npm
--- a/packaging/win/Dockerfile
+++ b/packaging/win/Dockerfile
@@ -0,0 +1,16 @@
+FROM ubuntu:precise
+MAINTAINER Lovell Fuller <npm@lovell.info>
+
+RUN apt-get update && apt-get install -y curl zip
+
+# Fetch and unzip
+RUN mkdir /vips
+WORKDIR /vips
+RUN curl -O http://www.vips.ecs.soton.ac.uk/supported/8.1/win32/vips-dev-w64-8.1.1-3.zip
+RUN unzip vips-dev-w64-8.1.1-3.zip
+
+# Clean and zip
+WORKDIR /vips/vips-dev-8.1.1
+RUN rm bin/libvipsCC-42.dll bin/libvips-cpp-42.dll bin/libgsf-win32-1-114.dll bin/libstdc++-6.dll
+RUN cp bin/*.dll lib/
+RUN GZIP=-9 tar czf /libvips-8.1.1-win.tar.gz include lib/glib-2.0 lib/libvips.lib lib/libglib-2.0.lib lib/libgobject-2.0.lib lib/*.dll
--- a/preinstall.sh
+++ b/preinstall.sh
@@ -33,7 +33,7 @@ install_libvips_from_source() {
  rm -rf vips-$vips_version_latest_major_minor.$vips_version_latest_patch
  rm vips-$vips_version_latest_major_minor.$vips_version_latest_patch.tar.gz
  ldconfig
-  echo "Installed libvips $vips_version_latest_major_minor.$vips_version_latest_patch"
+  echo "Installed libvips $(PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig:/usr/lib/pkgconfig pkg-config --modversion vips)"
 }

 install_libopenslide_from_source() {
@@ -249,14 +249,14 @@ elif [ -f /etc/redhat-release ]; then
      # RHEL/CentOS 7
      echo "Installing libvips dependencies via yum"
      yum groupinstall -y "Development Tools"
-      yum install -y gtk-doc libxml2-devel libjpeg-turbo-devel libpng-devel libtiff-devel libexif-devel libgsf-devel lcms2-devel ImageMagick-devel gobject-introspection-devel libwebp-devel curl
+      yum install -y tar curl gtk-doc libxml2-devel libjpeg-turbo-devel libpng-devel libtiff-devel libexif-devel libgsf-devel lcms2-devel ImageMagick-devel gobject-introspection-devel libwebp-devel
      install_libvips_from_source "--prefix=/usr"
      ;;
    "Red Hat Enterprise Linux release 6."*|"CentOS release 6."*|"Scientific Linux release 6."*)
      # RHEL/CentOS 6
      echo "Installing libvips dependencies via yum"
      yum groupinstall -y "Development Tools"
-      yum install -y gtk-doc libxml2-devel libjpeg-turbo-devel libpng-devel libtiff-devel libexif-devel libgsf-devel lcms-devel ImageMagick-devel curl
+      yum install -y tar curl gtk-doc libxml2-devel libjpeg-turbo-devel libpng-devel libtiff-devel libexif-devel libgsf-devel lcms-devel ImageMagick-devel
      yum install -y http://li.nux.ro/download/nux/dextop/el6/x86_64/nux-dextop-release-0-2.el6.nux.noarch.rpm
      yum install -y --enablerepo=nux-dextop gobject-introspection-devel
      yum install -y http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
--- a/src/common.cc
+++ b/src/common.cc
@@ -7,12 +7,8 @@

 // Verify platform and compiler compatibility

-#if (VIPS_MAJOR_VERSION < 7 || (VIPS_MAJOR_VERSION == 7 && VIPS_MINOR_VERSION < 40))
-#error libvips version 7.40.0+ required - see http://sharp.dimens.io/page/install
-#endif
-
-#ifdef _WIN64
-#error Windows 64-bit is currently unsupported - see http://sharp.dimens.io/page/install#windows
+#if (VIPS_MAJOR_VERSION < 8 || (VIPS_MAJOR_VERSION == 8 && VIPS_MINOR_VERSION < 1 && VIPS_PATCH_VERSION < 1))
+#error libvips version 8.1.1+ required - see http://sharp.dimens.io/page/install
 #endif

 #if ((!defined(__clang__)) && defined(__GNUC__) && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)))
@@ -82,7 +78,7 @@ namespace sharp {
    Initialise and return a VipsImage from a buffer. Supports JPEG, PNG, WebP and TIFF.
  */
  VipsImage* InitImage(void *buffer, size_t const length, VipsAccess const access) {
-    return vips_image_new_from_buffer(buffer, length, NULL, "access", access, NULL);
+    return vips_image_new_from_buffer(buffer, length, nullptr, "access", access, nullptr);
  }

  /*
@@ -91,7 +87,7 @@ namespace sharp {
  ImageType DetermineImageType(char const *file) {
    ImageType imageType = ImageType::UNKNOWN;
    char const *load = vips_foreign_find_load(file);
-    if (load != NULL) {
+    if (load != nullptr) {
      std::string loader = load;
      if (EndsWith(loader, "JpegFile")) {
        imageType = ImageType::JPEG;
@@ -114,7 +110,7 @@ namespace sharp {
    Initialise and return a VipsImage from a file.
  */
  VipsImage* InitImage(char const *file, VipsAccess const access) {
-    return vips_image_new_from_file(file, "access", access, NULL);
+    return vips_image_new_from_file(file, "access", access, nullptr);
  }

  /*
@@ -173,7 +169,7 @@ namespace sharp {
  */
  int InterpolatorWindowSize(char const *name) {
    VipsInterpolate *interpolator = vips_interpolate_new(name);
-    if (interpolator == NULL) {
+    if (interpolator == nullptr) {
      return -1;
    }
    int window_size = vips_interpolate_get_window_size(interpolator);
@@ -181,4 +177,13 @@ namespace sharp {
    return window_size;
  }

+  /*
+    Called when a Buffer undergoes GC, required to support mixed runtime libraries in Windows
+  */
+  void FreeCallback(char* data, void* hint) {
+    if (data != nullptr) {
+      g_free(data);
+    }
+  }
+
 } // namespace sharp
--- a/src/common.h
+++ b/src/common.h
@@ -80,6 +80,11 @@ namespace sharp {
  */
  int InterpolatorWindowSize(char const *name);

+  /*
+    Called when a Buffer undergoes GC, required to support mixed runtime libraries in Windows
+  */
+  void FreeCallback(char* data, void* hint);
+
 }  // namespace sharp

 #endif  // SRC_COMMON_H_
--- a/src/metadata.cc
+++ b/src/metadata.cc
@@ -35,6 +35,7 @@ using sharp::InitImage;
 using sharp::HasProfile;
 using sharp::HasAlpha;
 using sharp::ExifOrientation;
+using sharp::FreeCallback;
 using sharp::counterQueue;

 struct MetadataBaton {
@@ -64,20 +65,15 @@ struct MetadataBaton {
    iccLength(0) {}
 };

-/*
-  Delete input char[] buffer and notify V8 of memory deallocation
-  Used as the callback function for the "postclose" signal
-*/
-static void DeleteBuffer(VipsObject *object, char *buffer) {
-  if (buffer != NULL) {
-    delete[] buffer;
-  }
-}
-
 class MetadataWorker : public AsyncWorker {

 public:
-  MetadataWorker(Callback *callback, MetadataBaton *baton) : AsyncWorker(callback), baton(baton) {}
+  MetadataWorker(Callback *callback, MetadataBaton *baton, const Local<Object> &bufferIn) :
+    AsyncWorker(callback), baton(baton) {
+      if (baton->bufferInLength > 0) {
+        SaveToPersistent("bufferIn", bufferIn);
+      }
+    }
  ~MetadataWorker() {}

  void Execute() {
@@ -85,30 +81,25 @@ class MetadataWorker : public AsyncWorker {
    g_atomic_int_dec_and_test(&counterQueue);

    ImageType imageType = ImageType::UNKNOWN;
-    VipsImage *image = NULL;
+    VipsImage *image = nullptr;
    if (baton->bufferInLength > 0) {
      // From buffer
      imageType = DetermineImageType(baton->bufferIn, baton->bufferInLength);
      if (imageType != ImageType::UNKNOWN) {
        image = InitImage(baton->bufferIn, baton->bufferInLength, VIPS_ACCESS_RANDOM);
-        if (image != NULL) {
-          // Listen for "postclose" signal to delete input buffer
-          g_signal_connect(image, "postclose", G_CALLBACK(DeleteBuffer), baton->bufferIn);
-        } else {
+        if (image == nullptr) {
          (baton->err).append("Input buffer has corrupt header");
          imageType = ImageType::UNKNOWN;
-          DeleteBuffer(NULL, baton->bufferIn);
        }
      } else {
        (baton->err).append("Input buffer contains unsupported image format");
-        DeleteBuffer(NULL, baton->bufferIn);
      }
    } else {
      // From file
-      imageType = DetermineImageType(baton->fileIn.c_str());
+      imageType = DetermineImageType(baton->fileIn.data());
      if (imageType != ImageType::UNKNOWN) {
-        image = InitImage(baton->fileIn.c_str(), VIPS_ACCESS_RANDOM);
-        if (image == NULL) {
+        image = InitImage(baton->fileIn.data(), VIPS_ACCESS_RANDOM);
+        if (image == nullptr) {
          (baton->err).append("Input file has corrupt header");
          imageType = ImageType::UNKNOWN;
        }
@@ -116,7 +107,7 @@ class MetadataWorker : public AsyncWorker {
        (baton->err).append("Input file is of an unsupported image format");
      }
    }
-    if (image != NULL && imageType != ImageType::UNKNOWN) {
+    if (image != nullptr && imageType != ImageType::UNKNOWN) {
      // Image type
      switch (imageType) {
        case ImageType::JPEG: baton->format = "jpeg"; break;
@@ -142,7 +133,7 @@ class MetadataWorker : public AsyncWorker {
        size_t exifLength;
        if (!vips_image_get_blob(image, VIPS_META_EXIF_NAME, &exif, &exifLength)) {
          baton->exifLength = exifLength;
-          baton->exif = static_cast<char*>(malloc(exifLength));
+          baton->exif = static_cast<char*>(g_malloc(exifLength));
          memcpy(baton->exif, exif, exifLength);
        }
      }
@@ -152,7 +143,7 @@ class MetadataWorker : public AsyncWorker {
        size_t iccLength;
        if (!vips_image_get_blob(image, VIPS_META_ICC_NAME, &icc, &iccLength)) {
          baton->iccLength = iccLength;
-          baton->icc = static_cast<char*>(malloc(iccLength));
+          baton->icc = static_cast<char*>(g_malloc(iccLength));
          memcpy(baton->icc, icc, iccLength);
        }
      }
@@ -170,7 +161,7 @@ class MetadataWorker : public AsyncWorker {
    Local<Value> argv[2] = { Null(), Null() };
    if (!baton->err.empty()) {
      // Error
-      argv[0] = Error(baton->err.c_str());
+      argv[0] = Error(baton->err.data());
    } else {
      // Metadata Object
      Local<Object> info = New<Object>();
@@ -185,13 +176,24 @@ class MetadataWorker : public AsyncWorker {
        Set(info, New("orientation").ToLocalChecked(), New<Number>(baton->orientation));
      }
      if (baton->exifLength > 0) {
-        Set(info, New("exif").ToLocalChecked(), NewBuffer(baton->exif, baton->exifLength).ToLocalChecked());
+        Set(info,
+          New("exif").ToLocalChecked(),
+          NewBuffer(baton->exif, baton->exifLength, FreeCallback, nullptr).ToLocalChecked()
+        );
      }
      if (baton->iccLength > 0) {
-        Set(info, New("icc").ToLocalChecked(), NewBuffer(baton->icc, baton->iccLength).ToLocalChecked());
+        Set(info,
+          New("icc").ToLocalChecked(),
+          NewBuffer(baton->icc, baton->iccLength, FreeCallback, nullptr).ToLocalChecked()
+        );
      }
      argv[1] = info;
    }
+
+    // Dispose of Persistent wrapper around input Buffer so it can be garbage collected
+    if (baton->bufferInLength > 0) {
+      GetFromPersistent("bufferIn");
+    }
    delete baton;

    // Return to JavaScript
@@ -215,17 +217,16 @@ NAN_METHOD(metadata) {
  // Input filename
  baton->fileIn = *Utf8String(Get(options, New("fileIn").ToLocalChecked()).ToLocalChecked());
  // Input Buffer object
+  Local<Object> bufferIn;
  if (node::Buffer::HasInstance(Get(options, New("bufferIn").ToLocalChecked()).ToLocalChecked())) {
-    Local<Object> buffer = Get(options, New("bufferIn").ToLocalChecked()).ToLocalChecked().As<Object>();
-    // Take a copy of the input Buffer to avoid problems with V8 heap compaction
-    baton->bufferInLength = node::Buffer::Length(buffer);
-    baton->bufferIn = new char[baton->bufferInLength];
-    memcpy(baton->bufferIn, node::Buffer::Data(buffer), baton->bufferInLength);
+    bufferIn = Get(options, New("bufferIn").ToLocalChecked()).ToLocalChecked().As<Object>();
+    baton->bufferInLength = node::Buffer::Length(bufferIn);
+    baton->bufferIn = node::Buffer::Data(bufferIn);
  }

  // Join queue for worker thread
  Callback *callback = new Callback(info[1].As<Function>());
-  AsyncQueueWorker(new MetadataWorker(callback, baton));
+  AsyncQueueWorker(new MetadataWorker(callback, baton, bufferIn));

  // Increment queued task counter
  g_atomic_int_inc(&counterQueue);
--- a/src/operations.cc
+++ b/src/operations.cc
@@ -14,11 +14,11 @@ namespace sharp {

    // Split src into non-alpha and alpha
    VipsImage *srcWithoutAlpha;
-    if (vips_extract_band(src, &srcWithoutAlpha, 0, "n", src->Bands - 1, NULL))
+    if (vips_extract_band(src, &srcWithoutAlpha, 0, "n", src->Bands - 1, nullptr))
      return -1;
    vips_object_local(context, srcWithoutAlpha);
    VipsImage *srcAlpha;
-    if (vips_extract_band(src, &srcAlpha, src->Bands - 1, "n", 1, NULL))
+    if (vips_extract_band(src, &srcAlpha, src->Bands - 1, "n", 1, nullptr))
      return -1;
    vips_object_local(context, srcAlpha);

@@ -27,12 +27,12 @@ namespace sharp {
    VipsImage *dstAlpha;
    if (HasAlpha(dst)) {
      // Non-alpha: extract all-but-last channel
-      if (vips_extract_band(dst, &dstWithoutAlpha, 0, "n", dst->Bands - 1, NULL)) {
+      if (vips_extract_band(dst, &dstWithoutAlpha, 0, "n", dst->Bands - 1, nullptr)) {
        return -1;
      }
      vips_object_local(context, dstWithoutAlpha);
      // Alpha: Extract last channel
-      if (vips_extract_band(dst, &dstAlpha, dst->Bands - 1, "n", 1, NULL)) {
+      if (vips_extract_band(dst, &dstAlpha, dst->Bands - 1, "n", 1, nullptr)) {
        return -1;
      }
      vips_object_local(context, dstAlpha);
@@ -41,11 +41,11 @@ namespace sharp {
      dstWithoutAlpha = dst;
      // Alpha: Use blank, opaque (0xFF) image
      VipsImage *black;
-      if (vips_black(&black, dst->Xsize, dst->Ysize, NULL)) {
+      if (vips_black(&black, dst->Xsize, dst->Ysize, nullptr)) {
        return -1;
      }
      vips_object_local(context, black);
-      if (vips_invert(black, &dstAlpha, NULL)) {
+      if (vips_invert(black, &dstAlpha, nullptr)) {
        return -1;
      }
      vips_object_local(context, dstAlpha);
@@ -53,12 +53,12 @@ namespace sharp {

    // Compute normalized input alpha channels:
    VipsImage *srcAlphaNormalized;
-    if (vips_linear1(srcAlpha, &srcAlphaNormalized, 1.0 / 255.0, 0.0, NULL))
+    if (vips_linear1(srcAlpha, &srcAlphaNormalized, 1.0 / 255.0, 0.0, nullptr))
      return -1;
    vips_object_local(context, srcAlphaNormalized);

    VipsImage *dstAlphaNormalized;
-    if (vips_linear1(dstAlpha, &dstAlphaNormalized, 1.0 / 255.0, 0.0, NULL))
+    if (vips_linear1(dstAlpha, &dstAlphaNormalized, 1.0 / 255.0, 0.0, nullptr))
      return -1;
    vips_object_local(context, dstAlphaNormalized);

@@ -75,17 +75,17 @@ namespace sharp {
    //                 ^^^^^^^^^^^^^^^^^^^
    //                         t1
    VipsImage *t0;
-    if (vips_linear1(srcAlphaNormalized, &t0, -1.0, 1.0, NULL))
+    if (vips_linear1(srcAlphaNormalized, &t0, -1.0, 1.0, nullptr))
      return -1;
    vips_object_local(context, t0);

    VipsImage *t1;
-    if (vips_multiply(dstAlphaNormalized, t0, &t1, NULL))
+    if (vips_multiply(dstAlphaNormalized, t0, &t1, nullptr))
      return -1;
    vips_object_local(context, t1);

    VipsImage *outAlphaNormalized;
-    if (vips_add(srcAlphaNormalized, t1, &outAlphaNormalized, NULL))
+    if (vips_add(srcAlphaNormalized, t1, &outAlphaNormalized, nullptr))
      return -1;
    vips_object_local(context, outAlphaNormalized);

@@ -102,92 +102,29 @@ namespace sharp {
    // externally.
    //
    VipsImage *t2;
-    if (vips_multiply(dstWithoutAlpha, t0, &t2, NULL))
+    if (vips_multiply(dstWithoutAlpha, t0, &t2, nullptr))
      return -1;
    vips_object_local(context, t2);

    VipsImage *outRGBPremultiplied;
-    if (vips_add(srcWithoutAlpha, t2, &outRGBPremultiplied, NULL))
+    if (vips_add(srcWithoutAlpha, t2, &outRGBPremultiplied, nullptr))
      return -1;
    vips_object_local(context, outRGBPremultiplied);

    // Denormalize output alpha channel:
    VipsImage *outAlpha;
-    if (vips_linear1(outAlphaNormalized, &outAlpha, 255.0, 0.0, NULL))
+    if (vips_linear1(outAlphaNormalized, &outAlpha, 255.0, 0.0, nullptr))
      return -1;
    vips_object_local(context, outAlpha);

    // Combine RGB and alpha channel into output image:
-    return vips_bandjoin2(outRGBPremultiplied, outAlpha, out, NULL);
-  }
-
-  /*
-   * Premultiply alpha channel of `image`.
-   */
-  int Premultiply(VipsObject *context, VipsImage *image, VipsImage **out) {
-#if (VIPS_MAJOR_VERSION >= 9 || (VIPS_MAJOR_VERSION >= 8 && VIPS_MINOR_VERSION >= 1))
-    return vips_premultiply(image, out, NULL);
-#else
-    VipsImage *imageRGB;
-    if (vips_extract_band(image, &imageRGB, 0, "n", image->Bands - 1, NULL))
-      return -1;
-    vips_object_local(context, imageRGB);
-
-    VipsImage *imageAlpha;
-    if (vips_extract_band(image, &imageAlpha, image->Bands - 1, "n", 1, NULL))
-      return -1;
-    vips_object_local(context, imageAlpha);
-
-    VipsImage *imageAlphaNormalized;
-    if (vips_linear1(imageAlpha, &imageAlphaNormalized, 1.0 / 255.0, 0.0, NULL))
-      return -1;
-    vips_object_local(context, imageAlphaNormalized);
-
-    VipsImage *imageRGBPremultiplied;
-    if (vips_multiply(imageRGB, imageAlphaNormalized, &imageRGBPremultiplied, NULL))
-      return -1;
-    vips_object_local(context, imageRGBPremultiplied);
-
-    return vips_bandjoin2(imageRGBPremultiplied, imageAlpha, out, NULL);
-#endif
-  }
-
-  /*
-   * Unpremultiply alpha channel of `image`.
-   */
-  int Unpremultiply(VipsObject *context, VipsImage *image, VipsImage **out) {
-#if (VIPS_MAJOR_VERSION >= 9 || (VIPS_MAJOR_VERSION >= 8 && VIPS_MINOR_VERSION >= 1))
-    return vips_unpremultiply(image, out, NULL);
-#else
-    VipsImage *imageRGBPremultipliedTransformed;
-    if (vips_extract_band(image, &imageRGBPremultipliedTransformed, 0, "n", image->Bands - 1, NULL))
-      return -1;
-    vips_object_local(context, imageRGBPremultipliedTransformed);
-
-    VipsImage *imageAlphaTransformed;
-    if (vips_extract_band(image, &imageAlphaTransformed, image->Bands - 1, "n", 1, NULL))
-      return -1;
-    vips_object_local(context, imageAlphaTransformed);
-
-    VipsImage *imageAlphaNormalizedTransformed;
-    if (vips_linear1(imageAlphaTransformed, &imageAlphaNormalizedTransformed, 1.0 / 255.0, 0.0, NULL))
-      return -1;
-    vips_object_local(context, imageAlphaNormalizedTransformed);
-
-    VipsImage *imageRGBUnpremultipliedTransformed;
-    if (vips_divide(imageRGBPremultipliedTransformed, imageAlphaNormalizedTransformed, &imageRGBUnpremultipliedTransformed, NULL))
-      return -1;
-    vips_object_local(context, imageRGBUnpremultipliedTransformed);
-
-    return vips_bandjoin2(imageRGBUnpremultipliedTransformed, imageAlphaTransformed, out, NULL);
-#endif
+    return vips_bandjoin2(outRGBPremultiplied, outAlpha, out, nullptr);
  }

  /*
   * Stretch luminance to cover full dynamic range.
   */
  int Normalize(VipsObject *context, VipsImage *image, VipsImage **out) {
-#ifndef _WIN32
    // Get original colourspace
    VipsInterpretation typeBeforeNormalize = image->Type;
    if (typeBeforeNormalize == VIPS_INTERPRETATION_RGB) {
@@ -195,25 +132,25 @@ namespace sharp {
    }
    // Convert to LAB colourspace
    VipsImage *lab;
-    if (vips_colourspace(image, &lab, VIPS_INTERPRETATION_LAB, NULL)) {
+    if (vips_colourspace(image, &lab, VIPS_INTERPRETATION_LAB, nullptr)) {
      return -1;
    }
    vips_object_local(context, lab);
    // Extract luminance
    VipsImage *luminance;
-    if (vips_extract_band(lab, &luminance, 0, "n", 1, NULL)) {
+    if (vips_extract_band(lab, &luminance, 0, "n", 1, nullptr)) {
      return -1;
    }
    vips_object_local(context, luminance);
    // Extract chroma
    VipsImage *chroma;
-    if (vips_extract_band(lab, &chroma, 1, "n", 2, NULL)) {
+    if (vips_extract_band(lab, &chroma, 1, "n", 2, nullptr)) {
      return -1;
    }
    vips_object_local(context, chroma);
    // Find luminance range
    VipsImage *stats;
-    if (vips_stats(luminance, &stats, NULL)) {
+    if (vips_stats(luminance, &stats, nullptr)) {
      return -1;
    }
    vips_object_local(context, stats);
@@ -224,19 +161,19 @@ namespace sharp {
      double a = -(min * f);
      // Scale luminance
      VipsImage *luminance100;
-      if (vips_linear1(luminance, &luminance100, f, a, NULL)) {
+      if (vips_linear1(luminance, &luminance100, f, a, nullptr)) {
        return -1;
      }
      vips_object_local(context, luminance100);
      // Join scaled luminance to chroma
      VipsImage *normalizedLab;
-      if (vips_bandjoin2(luminance100, chroma, &normalizedLab, NULL)) {
+      if (vips_bandjoin2(luminance100, chroma, &normalizedLab, nullptr)) {
        return -1;
      }
      vips_object_local(context, normalizedLab);
      // Convert to original colourspace
      VipsImage *normalized;
-      if (vips_colourspace(normalizedLab, &normalized, typeBeforeNormalize, NULL)) {
+      if (vips_colourspace(normalizedLab, &normalized, typeBeforeNormalize, nullptr)) {
        return -1;
      }
      vips_object_local(context, normalized);
@@ -244,13 +181,13 @@ namespace sharp {
      if (HasAlpha(image)) {
        // Extract original alpha channel
        VipsImage *alpha;
-        if (vips_extract_band(image, &alpha, image->Bands - 1, "n", 1, NULL)) {
+        if (vips_extract_band(image, &alpha, image->Bands - 1, "n", 1, nullptr)) {
          return -1;
        }
        vips_object_local(context, alpha);
        // Join alpha channel to normalised image
        VipsImage *normalizedAlpha;
-        if (vips_bandjoin2(normalized, alpha, &normalizedAlpha, NULL)) {
+        if (vips_bandjoin2(normalized, alpha, &normalizedAlpha, nullptr)) {
          return -1;
        }
        vips_object_local(context, normalizedAlpha);
@@ -262,11 +199,6 @@ namespace sharp {
      // Cannot normalise zero-range image
      *out = image;
    }
-#else
-    // The normalize operation is currently unsupported on Windows
-    // See https://github.com/lovell/sharp/issues/152
-    *out = image;
-#endif
    return 0;
  }

@@ -283,19 +215,19 @@ namespace sharp {
        1.0, 1.0, 1.0);
      vips_image_set_double(blur, "scale", 9);
      vips_object_local(context, blur);
-      if (vips_conv(image, &blurred, blur, NULL)) {
+      if (vips_conv(image, &blurred, blur, nullptr)) {
        return -1;
      }
    } else {
      // Slower, accurate Gaussian blur
      // Create Gaussian function for standard deviation
      VipsImage *gaussian;
-      if (vips_gaussmat(&gaussian, sigma, 0.2, "separable", TRUE, "integer", TRUE, NULL)) {
+      if (vips_gaussmat(&gaussian, sigma, 0.2, "separable", TRUE, "integer", TRUE, nullptr)) {
        return -1;
      }
      vips_object_local(context, gaussian);
      // Apply Gaussian function
-      if (vips_convsep(image, &blurred, gaussian, "precision", VIPS_PRECISION_INTEGER, NULL)) {
+      if (vips_convsep(image, &blurred, gaussian, "precision", VIPS_PRECISION_INTEGER, nullptr)) {
        return -1;
      }
    }
@@ -317,12 +249,12 @@ namespace sharp {
        -1.0, -1.0, -1.0);
      vips_image_set_double(sharpen, "scale", 24);
      vips_object_local(context, sharpen);
-      if (vips_conv(image, &sharpened, sharpen, NULL)) {
+      if (vips_conv(image, &sharpened, sharpen, nullptr)) {
        return -1;
      }
    } else {
      // Slow, accurate sharpen in LAB colour space, with control over flat vs jagged areas
-      if (vips_sharpen(image, &sharpened, "radius", radius, "m1", flat, "m2", jagged, NULL)) {
+      if (vips_sharpen(image, &sharpened, "radius", radius, "m1", flat, "m2", jagged, nullptr)) {
        return -1;
      }
    }
@@ -330,4 +262,21 @@ namespace sharp {
    *out = sharpened;
    return 0;
  }
+
+  int Threshold(VipsObject *context, VipsImage *image, VipsImage **out, int threshold) {
+      VipsImage *greyscale;
+      if (vips_colourspace(image, &greyscale, VIPS_INTERPRETATION_B_W, nullptr)) {
+        return -1;
+      }
+      vips_object_local(context, greyscale);
+      image = greyscale;
+
+      VipsImage *thresholded;
+      if (vips_moreeq_const1(image, &thresholded, threshold, nullptr)) {
+          return -1;
+      }
+      vips_object_local(context, thresholded);
+      *out = thresholded;
+      return 0;
+  }
 }  // namespace sharp
--- a/src/operations.h
+++ b/src/operations.h
@@ -9,16 +9,6 @@ namespace sharp {
   */
  int Composite(VipsObject *context, VipsImage *src, VipsImage *dst, VipsImage **out);

-  /*
-   * Premultiply alpha channel of `image`.
-   */
-  int Premultiply(VipsObject *context, VipsImage *image, VipsImage **out);
-
-  /*
-   * Unpremultiply alpha channel of `image`.
-   */
-  int Unpremultiply(VipsObject *context, VipsImage *image, VipsImage **out);
-
  /*
   * Stretch luminance to cover full dynamic range.
   */
@@ -34,6 +24,11 @@ namespace sharp {
   */
  int Sharpen(VipsObject *context, VipsImage *image, VipsImage **out, int radius, double flat, double jagged);

+  /*
+   * Perform thresholding on an image.  If the image is not greyscale, will convert before thresholding.
+   * Pixels with a greyscale value greater-than-or-equal-to `threshold` will be pure white.  All others will be pure black.
+   */
+  int Threshold(VipsObject *context, VipsImage *image, VipsImage **out, int threshold);
 }  // namespace sharp

 #endif  // SRC_OPERATIONS_H_
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -32,16 +32,15 @@ using Nan::Get;
 using Nan::Set;
 using Nan::To;
 using Nan::New;
-using Nan::CopyBuffer;
+using Nan::NewBuffer;
 using Nan::Null;
 using Nan::Equals;

 using sharp::Composite;
-using sharp::Premultiply;
-using sharp::Unpremultiply;
 using sharp::Normalize;
 using sharp::Blur;
 using sharp::Sharpen;
+using sharp::Threshold;

 using sharp::ImageType;
 using sharp::DetermineImageType;
@@ -57,6 +56,7 @@ using sharp::IsPng;
 using sharp::IsWebp;
 using sharp::IsTiff;
 using sharp::IsDz;
+using sharp::FreeCallback;
 using sharp::counterProcess;
 using sharp::counterQueue;

@@ -101,10 +101,12 @@ struct PipelineBaton {
  std::string interpolator;
  double background[4];
  bool flatten;
+  bool negate;
  double blurSigma;
  int sharpenRadius;
  double sharpenFlat;
  double sharpenJagged;
+  int threshold;
  std::string overlayPath;
  double gamma;
  bool greyscale;
@@ -139,10 +141,12 @@ struct PipelineBaton {
    canvas(Canvas::CROP),
    gravity(0),
    flatten(false),
+    negate(false),
    blurSigma(0.0),
    sharpenRadius(0),
    sharpenFlat(1.0),
    sharpenJagged(2.0),
+    threshold(0),
    gamma(0.0),
    greyscale(false),
    normalize(false),
@@ -169,21 +173,15 @@ struct PipelineBaton {
    }
 };

-/*
-  Delete input char[] buffer and notify V8 of memory deallocation
-  Used as the callback function for the "postclose" signal
-*/
-static void DeleteBuffer(VipsObject *object, char *buffer) {
-  if (buffer != NULL) {
-    delete[] buffer;
-  }
-}
-
 class PipelineWorker : public AsyncWorker {

 public:
-  PipelineWorker(Callback *callback, PipelineBaton *baton, Callback *queueListener) :
-    AsyncWorker(callback), baton(baton), queueListener(queueListener) {}
+  PipelineWorker(Callback *callback, PipelineBaton *baton, Callback *queueListener, const Local<Object> &bufferIn) :
+    AsyncWorker(callback), baton(baton), queueListener(queueListener) {
+      if (baton->bufferInLength > 0) {
+        SaveToPersistent("bufferIn", bufferIn);
+      }
+    }
  ~PipelineWorker() {}

  /*
@@ -204,31 +202,26 @@ class PipelineWorker : public AsyncWorker {

    // Input
    ImageType inputImageType = ImageType::UNKNOWN;
-    VipsImage *image = NULL;
+    VipsImage *image = nullptr;
    if (baton->bufferInLength > 0) {
      // From buffer
      inputImageType = DetermineImageType(baton->bufferIn, baton->bufferInLength);
      if (inputImageType != ImageType::UNKNOWN) {
        image = InitImage(baton->bufferIn, baton->bufferInLength, baton->accessMethod);
-        if (image != NULL) {
-          // Listen for "postclose" signal to delete input buffer
-          g_signal_connect(image, "postclose", G_CALLBACK(DeleteBuffer), baton->bufferIn);
-        } else {
+        if (image == nullptr) {
          // Could not read header data
          (baton->err).append("Input buffer has corrupt header");
          inputImageType = ImageType::UNKNOWN;
-          DeleteBuffer(NULL, baton->bufferIn);
        }
      } else {
        (baton->err).append("Input buffer contains unsupported image format");
-        DeleteBuffer(NULL, baton->bufferIn);
      }
    } else {
      // From file
-      inputImageType = DetermineImageType(baton->fileIn.c_str());
+      inputImageType = DetermineImageType(baton->fileIn.data());
      if (inputImageType != ImageType::UNKNOWN) {
-        image = InitImage(baton->fileIn.c_str(), baton->accessMethod);
-        if (image == NULL) {
+        image = InitImage(baton->fileIn.data(), baton->accessMethod);
+        if (image == nullptr) {
          (baton->err).append("Input file has corrupt header");
          inputImageType = ImageType::UNKNOWN;
        }
@@ -236,7 +229,7 @@ class PipelineWorker : public AsyncWorker {
        (baton->err).append("Input file is of an unsupported image format");
      }
    }
-    if (image == NULL || inputImageType == ImageType::UNKNOWN) {
+    if (image == nullptr || inputImageType == ImageType::UNKNOWN) {
      return Error();
    }
    vips_object_local(hook, image);
@@ -264,7 +257,7 @@ class PipelineWorker : public AsyncWorker {
    // Rotate pre-extract
    if (baton->rotateBeforePreExtract && rotation != Angle::D0) {
      VipsImage *rotated;
-      if (vips_rot(image, &rotated, static_cast<VipsAngle>(rotation), NULL)) {
+      if (vips_rot(image, &rotated, static_cast<VipsAngle>(rotation), nullptr)) {
        return Error();
      }
      vips_object_local(hook, rotated);
@@ -275,7 +268,7 @@ class PipelineWorker : public AsyncWorker {
    // Pre extraction
    if (baton->topOffsetPre != -1) {
      VipsImage *extractedPre;
-      if (vips_extract_area(image, &extractedPre, baton->leftOffsetPre, baton->topOffsetPre, baton->widthPre, baton->heightPre, NULL)) {
+      if (vips_extract_area(image, &extractedPre, baton->leftOffsetPre, baton->topOffsetPre, baton->widthPre, baton->heightPre, nullptr)) {
        return Error();
      }
      vips_object_local(hook, extractedPre);
@@ -285,7 +278,7 @@ class PipelineWorker : public AsyncWorker {
    // Get pre-resize image width and height
    int inputWidth = image->Xsize;
    int inputHeight = image->Ysize;
-    if (rotation == Angle::D90 || rotation == Angle::D270) {
+    if (!baton->rotateBeforePreExtract && (rotation == Angle::D90 || rotation == Angle::D270)) {
      // Swap input output width and height when rotating by 90 or 270 degrees
      int swap = inputWidth;
      inputWidth = inputHeight;
@@ -293,7 +286,7 @@ class PipelineWorker : public AsyncWorker {
    }

    // Get window size of interpolator, used for determining shrink vs affine
-    int interpolatorWindowSize = InterpolatorWindowSize(baton->interpolator.c_str());
+    int interpolatorWindowSize = InterpolatorWindowSize(baton->interpolator.data());
    if (interpolatorWindowSize < 0) {
      return Error();
    }
@@ -412,11 +405,11 @@ class PipelineWorker : public AsyncWorker {
      // Reload input using shrink-on-load
      VipsImage *shrunkOnLoad;
      if (baton->bufferInLength > 1) {
-        if (vips_jpegload_buffer(baton->bufferIn, baton->bufferInLength, &shrunkOnLoad, "shrink", shrink_on_load, NULL)) {
+        if (vips_jpegload_buffer(baton->bufferIn, baton->bufferInLength, &shrunkOnLoad, "shrink", shrink_on_load, nullptr)) {
          return Error();
        }
      } else {
-        if (vips_jpegload((baton->fileIn).c_str(), &shrunkOnLoad, "shrink", shrink_on_load, NULL)) {
+        if (vips_jpegload((baton->fileIn).data(), &shrunkOnLoad, "shrink", shrink_on_load, nullptr)) {
          return Error();
        }
      }
@@ -428,7 +421,7 @@ class PipelineWorker : public AsyncWorker {
    if (HasProfile(image)) {
      // Convert to sRGB using embedded profile
      VipsImage *transformed;
-      if (!vips_icc_transform(image, &transformed, srgbProfile.c_str(), "embedded", TRUE, NULL)) {
+      if (!vips_icc_transform(image, &transformed, srgbProfile.data(), "embedded", TRUE, nullptr)) {
        // Embedded profile can fail, so only update references on success
        vips_object_local(hook, transformed);
        image = transformed;
@@ -437,24 +430,29 @@ class PipelineWorker : public AsyncWorker {
      // Convert to sRGB using default "USWebCoatedSWOP" CMYK profile
      std::string cmykProfile = baton->iccProfilePath + "USWebCoatedSWOP.icc";
      VipsImage *transformed;
-      if (vips_icc_transform(image, &transformed, srgbProfile.c_str(), "input_profile", cmykProfile.c_str(), NULL)) {
+      if (vips_icc_transform(image, &transformed, srgbProfile.data(), "input_profile", cmykProfile.data(), nullptr)) {
        return Error();
      }
      vips_object_local(hook, transformed);
      image = transformed;
    }

+    // Calculate maximum alpha value based on input image pixel depth
+    double maxAlpha = (image->BandFmt == VIPS_FORMAT_USHORT) ? 65535.0 : 255.0;
+
    // Flatten image to remove alpha channel
    if (baton->flatten && HasAlpha(image)) {
+      // Scale up 8-bit values to match 16-bit input image
+      double multiplier = (image->Type == VIPS_INTERPRETATION_RGB16) ? 256.0 : 1.0;
      // Background colour
      VipsArrayDouble *background = vips_array_double_newv(
        3, // Ignore alpha channel as we're about to remove it
-        baton->background[0],
-        baton->background[1],
-        baton->background[2]
+        baton->background[0] * multiplier,
+        baton->background[1] * multiplier,
+        baton->background[2] * multiplier
      );
      VipsImage *flattened;
-      if (vips_flatten(image, &flattened, "background", background, NULL)) {
+      if (vips_flatten(image, &flattened, "background", background, "max_alpha", maxAlpha, nullptr)) {
        vips_area_unref(reinterpret_cast<VipsArea*>(background));
        return Error();
      }
@@ -463,10 +461,20 @@ class PipelineWorker : public AsyncWorker {
      image = flattened;
    }

+    // Negate the colors in the image.
+    if (baton->negate) {
+        VipsImage *negated;
+        if (vips_invert(image, &negated, nullptr)) {
+            return Error();
+        }
+        vips_object_local(hook, negated);
+        image = negated;
+    }
+
    // Gamma encoding (darken)
    if (baton->gamma >= 1 && baton->gamma <= 3 && !HasAlpha(image)) {
      VipsImage *gammaEncoded;
-      if (vips_gamma(image, &gammaEncoded, "exponent", 1.0 / baton->gamma, NULL)) {
+      if (vips_gamma(image, &gammaEncoded, "exponent", 1.0 / baton->gamma, nullptr)) {
        return Error();
      }
      vips_object_local(hook, gammaEncoded);
@@ -476,7 +484,7 @@ class PipelineWorker : public AsyncWorker {
    // Convert to greyscale (linear, therefore after gamma encoding, if any)
    if (baton->greyscale) {
      VipsImage *greyscale;
-      if (vips_colourspace(image, &greyscale, VIPS_INTERPRETATION_B_W, NULL)) {
+      if (vips_colourspace(image, &greyscale, VIPS_INTERPRETATION_B_W, nullptr)) {
        return Error();
      }
      vips_object_local(hook, greyscale);
@@ -486,7 +494,7 @@ class PipelineWorker : public AsyncWorker {
    if (xshrink > 1 || yshrink > 1) {
      VipsImage *shrunk;
      // Use vips_shrink with the integral reduction
-      if (vips_shrink(image, &shrunk, xshrink, yshrink, NULL)) {
+      if (vips_shrink(image, &shrunk, xshrink, yshrink, nullptr)) {
        return Error();
      }
      vips_object_local(hook, shrunk);
@@ -514,6 +522,7 @@ class PipelineWorker : public AsyncWorker {
    bool shouldAffineTransform = xresidual != 0.0 || yresidual != 0.0;
    bool shouldBlur = baton->blurSigma != 0.0;
    bool shouldSharpen = baton->sharpenRadius != 0;
+    bool shouldThreshold = baton->threshold != 0;
    bool hasOverlay = !baton->overlayPath.empty();
    bool shouldPremultiplyAlpha = HasAlpha(image) && (shouldAffineTransform || shouldBlur || shouldSharpen || hasOverlay);

@@ -522,7 +531,7 @@ class PipelineWorker : public AsyncWorker {
    // See: http://entropymine.com/imageworsener/resizealpha/
    if (shouldPremultiplyAlpha) {
      VipsImage *imagePremultiplied;
-      if (Premultiply(hook, image, &imagePremultiplied)) {
+      if (vips_premultiply(image, &imagePremultiplied, "max_alpha", maxAlpha, nullptr)) {
        (baton->err).append("Failed to premultiply alpha channel.");
        return Error();
      }
@@ -532,6 +541,12 @@ class PipelineWorker : public AsyncWorker {

    // Use vips_affine with the remaining float part
    if (shouldAffineTransform) {
+      // Create interpolator
+      VipsInterpolate *interpolator = vips_interpolate_new(baton->interpolator.data());
+      if (interpolator == nullptr) {
+        return Error();
+      }
+      vips_object_local(hook, interpolator);
      // Use average of x and y residuals to compute sigma for Gaussian blur
      double residual = (xresidual + yresidual) / 2.0;
      // Apply Gaussian blur before large affine reductions
@@ -539,39 +554,31 @@ class PipelineWorker : public AsyncWorker {
        // Calculate standard deviation
        double sigma = ((1.0 / residual) - 0.4) / 3.0;
        if (sigma >= 0.3) {
-          // Create Gaussian function for standard deviation
-          VipsImage *gaussian;
-          if (vips_gaussmat(&gaussian, sigma, 0.2, "separable", TRUE, "integer", TRUE, NULL)) {
-            return Error();
-          }
-          vips_object_local(hook, gaussian);
          // Sequential input requires a small linecache before use of convolution
          if (baton->accessMethod == VIPS_ACCESS_SEQUENTIAL) {
            VipsImage *lineCached;
-            if (vips_linecache(image, &lineCached, "access", VIPS_ACCESS_SEQUENTIAL, "tile_height", 1, "threaded", TRUE, NULL)) {
+            if (vips_linecache(image, &lineCached, "access", VIPS_ACCESS_SEQUENTIAL,
+              "tile_height", 1, "threaded", TRUE, nullptr)
+            ) {
              return Error();
            }
            vips_object_local(hook, lineCached);
            image = lineCached;
          }
-          // Apply Gaussian function
+          // Apply Gaussian blur
          VipsImage *blurred;
-          if (vips_convsep(image, &blurred, gaussian, "precision", VIPS_PRECISION_INTEGER, NULL)) {
+          if (vips_gaussblur(image, &blurred, sigma, nullptr)) {
            return Error();
          }
          vips_object_local(hook, blurred);
          image = blurred;
        }
      }
-      // Create interpolator - "bilinear" (default), "bicubic" or "nohalo"
-      VipsInterpolate *interpolator = vips_interpolate_new(baton->interpolator.c_str());
-      if (interpolator == NULL) {
-        return Error();
-      }
-      vips_object_local(hook, interpolator);
      // Perform affine transformation
      VipsImage *affined;
-      if (vips_affine(image, &affined, xresidual, 0.0, 0.0, yresidual, "interpolate", interpolator, NULL)) {
+      if (vips_affine(image, &affined, xresidual, 0.0, 0.0, yresidual,
+        "interpolate", interpolator, nullptr)
+      ) {
        return Error();
      }
      vips_object_local(hook, affined);
@@ -581,7 +588,7 @@ class PipelineWorker : public AsyncWorker {
    // Rotate
    if (!baton->rotateBeforePreExtract && rotation != Angle::D0) {
      VipsImage *rotated;
-      if (vips_rot(image, &rotated, static_cast<VipsAngle>(rotation), NULL)) {
+      if (vips_rot(image, &rotated, static_cast<VipsAngle>(rotation), nullptr)) {
        return Error();
      }
      vips_object_local(hook, rotated);
@@ -592,7 +599,7 @@ class PipelineWorker : public AsyncWorker {
    // Flip (mirror about Y axis)
    if (baton->flip) {
      VipsImage *flipped;
-      if (vips_flip(image, &flipped, VIPS_DIRECTION_VERTICAL, NULL)) {
+      if (vips_flip(image, &flipped, VIPS_DIRECTION_VERTICAL, nullptr)) {
        return Error();
      }
      vips_object_local(hook, flipped);
@@ -603,7 +610,7 @@ class PipelineWorker : public AsyncWorker {
    // Flop (mirror about X axis)
    if (baton->flop) {
      VipsImage *flopped;
-      if (vips_flip(image, &flopped, VIPS_DIRECTION_HORIZONTAL, NULL)) {
+      if (vips_flip(image, &flopped, VIPS_DIRECTION_HORIZONTAL, nullptr)) {
        return Error();
      }
      vips_object_local(hook, flopped);
@@ -618,7 +625,7 @@ class PipelineWorker : public AsyncWorker {
        if (image->Type != VIPS_INTERPRETATION_sRGB) {
          // Convert to sRGB colour space
          VipsImage *colourspaced;
-          if (vips_colourspace(image, &colourspaced, VIPS_INTERPRETATION_sRGB, NULL)) {
+          if (vips_colourspace(image, &colourspaced, VIPS_INTERPRETATION_sRGB, nullptr)) {
            return Error();
          }
          vips_object_local(hook, colourspaced);
@@ -628,19 +635,19 @@ class PipelineWorker : public AsyncWorker {
        if (baton->background[3] < 255.0 && !HasAlpha(image)) {
          // Create single-channel transparency
          VipsImage *black;
-          if (vips_black(&black, image->Xsize, image->Ysize, "bands", 1, NULL)) {
+          if (vips_black(&black, image->Xsize, image->Ysize, "bands", 1, nullptr)) {
            return Error();
          }
          vips_object_local(hook, black);
          // Invert to become non-transparent
          VipsImage *alpha;
-          if (vips_invert(black, &alpha, NULL)) {
+          if (vips_invert(black, &alpha, nullptr)) {
            return Error();
          }
          vips_object_local(hook, alpha);
          // Append alpha channel to existing image
          VipsImage *joined;
-          if (vips_bandjoin2(image, alpha, &joined, NULL)) {
+          if (vips_bandjoin2(image, alpha, &joined, nullptr)) {
            return Error();
          }
          vips_object_local(hook, joined);
@@ -662,7 +669,7 @@ class PipelineWorker : public AsyncWorker {
        int top = (baton->height - image->Ysize) / 2;
        VipsImage *embedded;
        if (vips_embed(image, &embedded, left, top, baton->width, baton->height,
-          "extend", VIPS_EXTEND_BACKGROUND, "background", background, NULL
+          "extend", VIPS_EXTEND_BACKGROUND, "background", background, nullptr
        )) {
          vips_area_unref(reinterpret_cast<VipsArea*>(background));
          return Error();
@@ -678,7 +685,7 @@ class PipelineWorker : public AsyncWorker {
        int width = std::min(image->Xsize, baton->width);
        int height = std::min(image->Ysize, baton->height);
        VipsImage *extracted;
-        if (vips_extract_area(image, &extracted, left, top, width, height, NULL)) {
+        if (vips_extract_area(image, &extracted, left, top, width, height, nullptr)) {
          return Error();
        }
        vips_object_local(hook, extracted);
@@ -690,7 +697,7 @@ class PipelineWorker : public AsyncWorker {
    if (baton->topOffsetPost != -1) {
      VipsImage *extractedPost;
      if (vips_extract_area(image, &extractedPost,
-        baton->leftOffsetPost, baton->topOffsetPost, baton->widthPost, baton->heightPost, NULL
+        baton->leftOffsetPost, baton->topOffsetPost, baton->widthPost, baton->heightPost, nullptr
      )) {
        return Error();
      }
@@ -698,6 +705,15 @@ class PipelineWorker : public AsyncWorker {
      image = extractedPost;
    }

+    // Threshold - must happen before blurring, due to the utility of blurring after thresholding
+    if (shouldThreshold) {
+        VipsImage *thresholded;
+        if (Threshold(hook, image, &thresholded, baton->threshold)) {
+            return Error();
+        }
+        image = thresholded;
+    }
+
    // Blur
    if (shouldBlur) {
      VipsImage *blurred;
@@ -718,12 +734,12 @@ class PipelineWorker : public AsyncWorker {

    // Composite with overlay, if present
    if (hasOverlay) {
-      VipsImage *overlayImage = NULL;
+      VipsImage *overlayImage = nullptr;
      ImageType overlayImageType = ImageType::UNKNOWN;
-      overlayImageType = DetermineImageType(baton->overlayPath.c_str());
+      overlayImageType = DetermineImageType(baton->overlayPath.data());
      if (overlayImageType != ImageType::UNKNOWN) {
-        overlayImage = InitImage(baton->overlayPath.c_str(), baton->accessMethod);
-        if (overlayImage == NULL) {
+        overlayImage = InitImage(baton->overlayPath.data(), baton->accessMethod);
+        if (overlayImage == nullptr) {
          (baton->err).append("Overlay image has corrupt header");
          return Error();
        } else {
@@ -754,15 +770,15 @@ class PipelineWorker : public AsyncWorker {

      // Ensure overlay is sRGB
      VipsImage *overlayImageRGB;
-      if (vips_colourspace(overlayImage, &overlayImageRGB, VIPS_INTERPRETATION_sRGB, NULL)) {
+      if (vips_colourspace(overlayImage, &overlayImageRGB, VIPS_INTERPRETATION_sRGB, nullptr)) {
        return Error();
      }
      vips_object_local(hook, overlayImageRGB);

      // Premultiply overlay
      VipsImage *overlayImagePremultiplied;
-      if (Premultiply(hook, overlayImageRGB, &overlayImagePremultiplied)) {
-        (baton->err).append("Failed to premultiply alpha channel of overlay image.");
+      if (vips_premultiply(overlayImageRGB, &overlayImagePremultiplied, nullptr)) {
+        (baton->err).append("Failed to premultiply alpha channel of overlay image");
        return Error();
      }
      vips_object_local(hook, overlayImagePremultiplied);
@@ -779,11 +795,10 @@ class PipelineWorker : public AsyncWorker {
    // Reverse premultiplication after all transformations:
    if (shouldPremultiplyAlpha) {
      VipsImage *imageUnpremultiplied;
-      if (Unpremultiply(hook, image, &imageUnpremultiplied)) {
-        (baton->err).append("Failed to unpremultiply alpha channel.");
+      if (vips_unpremultiply(image, &imageUnpremultiplied, "max_alpha", maxAlpha, nullptr)) {
+        (baton->err).append("Failed to unpremultiply alpha channel");
        return Error();
      }
-
      vips_object_local(hook, imageUnpremultiplied);
      image = imageUnpremultiplied;
    }
@@ -791,7 +806,7 @@ class PipelineWorker : public AsyncWorker {
    // Gamma decoding (brighten)
    if (baton->gamma >= 1 && baton->gamma <= 3 && !HasAlpha(image)) {
      VipsImage *gammaDecoded;
-      if (vips_gamma(image, &gammaDecoded, "exponent", baton->gamma, NULL)) {
+      if (vips_gamma(image, &gammaDecoded, "exponent", baton->gamma, nullptr)) {
        return Error();
      }
      vips_object_local(hook, gammaDecoded);
@@ -808,10 +823,27 @@ class PipelineWorker : public AsyncWorker {
    }

    // Convert image to sRGB, if not already
-    if (image->Type != VIPS_INTERPRETATION_sRGB) {
+    if (image->Type == VIPS_INTERPRETATION_RGB16) {
+      // Ensure 16-bit integer
+      VipsImage *ushort;
+      if (vips_cast_ushort(image, &ushort, nullptr)) {
+        return Error();
+      }
+      vips_object_local(hook, ushort);
+      image = ushort;
+      // Fast conversion to 8-bit integer by discarding least-significant byte
+      VipsImage *msb;
+      if (vips_msb(image, &msb, nullptr)) {
+        return Error();
+      }
+      vips_object_local(hook, msb);
+      image = msb;
+      // Explicitly set to sRGB
+      image->Type = VIPS_INTERPRETATION_sRGB;
+    } else if (image->Type != VIPS_INTERPRETATION_sRGB) {
      // Switch interpretation to sRGB
      VipsImage *rgb;
-      if (vips_colourspace(image, &rgb, VIPS_INTERPRETATION_sRGB, NULL)) {
+      if (vips_colourspace(image, &rgb, VIPS_INTERPRETATION_sRGB, nullptr)) {
        return Error();
      }
      vips_object_local(hook, rgb);
@@ -819,7 +851,7 @@ class PipelineWorker : public AsyncWorker {
      // Transform colours from embedded profile to sRGB profile
      if (baton->withMetadata && HasProfile(image)) {
        VipsImage *profiled;
-        if (vips_icc_transform(image, &profiled, srgbProfile.c_str(), "embedded", TRUE, NULL)) {
+        if (vips_icc_transform(image, &profiled, srgbProfile.data(), "embedded", TRUE, nullptr)) {
          return Error();
        }
        vips_object_local(hook, profiled);
@@ -832,63 +864,54 @@ class PipelineWorker : public AsyncWorker {
      SetExifOrientation(image, baton->withMetadataOrientation);
    }

-#if !(VIPS_MAJOR_VERSION >= 8 || (VIPS_MAJOR_VERSION >= 7 && VIPS_MINOR_VERSION >= 40 && VIPS_MINOR_VERSION >= 5))
-    // Generate image tile cache when interlace output is required - no longer required as of libvips 7.40.5+
-    if (baton->progressive) {
-      VipsImage *cached;
-      if (vips_tilecache(image, &cached, "threaded", TRUE, "persistent", TRUE, "max_tiles", -1, NULL)) {
-        return Error();
-      }
-      vips_object_local(hook, cached);
-      image = cached;
-    }
-#endif
-
    // Output
    if (baton->output == "__jpeg" || (baton->output == "__input" && inputImageType == ImageType::JPEG)) {
      // Write JPEG to buffer
-      if (vips_jpegsave_buffer(image, &baton->bufferOut, &baton->bufferOutLength, "strip", !baton->withMetadata,
-        "Q", baton->quality, "optimize_coding", TRUE, "no_subsample", baton->withoutChromaSubsampling,
-#if (VIPS_MAJOR_VERSION >= 8)
+      if (vips_jpegsave_buffer(
+        image, &baton->bufferOut, &baton->bufferOutLength,
+        "strip", !baton->withMetadata,
+        "Q", baton->quality,
+        "optimize_coding", TRUE,
+        "no_subsample", baton->withoutChromaSubsampling,
        "trellis_quant", baton->trellisQuantisation,
        "overshoot_deringing", baton->overshootDeringing,
        "optimize_scans", baton->optimiseScans,
-#endif
-        "interlace", baton->progressive, NULL)) {
+        "interlace", baton->progressive,
+        nullptr
+      )) {
        return Error();
      }
      baton->outputFormat = "jpeg";
    } else if (baton->output == "__png" || (baton->output == "__input" && inputImageType == ImageType::PNG)) {
-#if (VIPS_MAJOR_VERSION >= 8 || (VIPS_MAJOR_VERSION >= 7 && VIPS_MINOR_VERSION >= 42))
-      // Select PNG row filter
-      int filter = baton->withoutAdaptiveFiltering ? VIPS_FOREIGN_PNG_FILTER_NONE : VIPS_FOREIGN_PNG_FILTER_ALL;
      // Write PNG to buffer
-      if (vips_pngsave_buffer(image, &baton->bufferOut, &baton->bufferOutLength, "strip", !baton->withMetadata,
-        "compression", baton->compressionLevel, "interlace", baton->progressive, "filter", filter, NULL)) {
+      if (vips_pngsave_buffer(
+        image, &baton->bufferOut, &baton->bufferOutLength,
+        "strip", !baton->withMetadata,
+        "compression", baton->compressionLevel,
+        "interlace", baton->progressive,
+        "filter", baton->withoutAdaptiveFiltering ? VIPS_FOREIGN_PNG_FILTER_NONE : VIPS_FOREIGN_PNG_FILTER_ALL,
+        nullptr
+      )) {
        return Error();
      }
-#else
-      // Write PNG to buffer
-      if (vips_pngsave_buffer(image, &baton->bufferOut, &baton->bufferOutLength, "strip", !baton->withMetadata,
-        "compression", baton->compressionLevel, "interlace", baton->progressive, NULL)) {
-        return Error();
-      }
-#endif
      baton->outputFormat = "png";
    } else if (baton->output == "__webp" || (baton->output == "__input" && inputImageType == ImageType::WEBP)) {
      // Write WEBP to buffer
-      if (vips_webpsave_buffer(image, &baton->bufferOut, &baton->bufferOutLength, "strip", !baton->withMetadata,
-        "Q", baton->quality, NULL)) {
+      if (vips_webpsave_buffer(
+        image, &baton->bufferOut, &baton->bufferOutLength,
+        "strip", !baton->withMetadata,
+        "Q", baton->quality,
+        nullptr
+      )) {
        return Error();
      }
      baton->outputFormat = "webp";
-#if (VIPS_MAJOR_VERSION >= 8 || (VIPS_MAJOR_VERSION >= 7 && VIPS_MINOR_VERSION >= 42))
    } else if (baton->output == "__raw") {
      // Write raw, uncompressed image data to buffer
      if (baton->greyscale || image->Type == VIPS_INTERPRETATION_B_W) {
        // Extract first band for greyscale image
        VipsImage *grey;
-        if (vips_extract_band(image, &grey, 0, NULL)) {
+        if (vips_extract_band(image, &grey, 0, nullptr)) {
          return Error();
        }
        vips_object_local(hook, grey);
@@ -897,7 +920,7 @@ class PipelineWorker : public AsyncWorker {
      if (image->BandFmt != VIPS_FORMAT_UCHAR) {
        // Cast pixels to uint8 (unsigned char)
        VipsImage *uchar;
-        if (vips_cast(image, &uchar, VIPS_FORMAT_UCHAR, NULL)) {
+        if (vips_cast(image, &uchar, VIPS_FORMAT_UCHAR, nullptr)) {
          return Error();
        }
        vips_object_local(hook, uchar);
@@ -905,12 +928,11 @@ class PipelineWorker : public AsyncWorker {
      }
      // Get raw image data
      baton->bufferOut = vips_image_write_to_memory(image, &baton->bufferOutLength);
-      if (baton->bufferOut == NULL) {
+      if (baton->bufferOut == nullptr) {
        (baton->err).append("Could not allocate enough memory for raw output");
        return Error();
      }
      baton->outputFormat = "raw";
-#endif
    } else {
      bool outputJpeg = IsJpeg(baton->output);
      bool outputPng = IsPng(baton->output);
@@ -920,52 +942,66 @@ class PipelineWorker : public AsyncWorker {
      bool matchInput = !(outputJpeg || outputPng || outputWebp || outputTiff || outputDz);
      if (outputJpeg || (matchInput && inputImageType == ImageType::JPEG)) {
        // Write JPEG to file
-        if (vips_jpegsave(image, baton->output.c_str(), "strip", !baton->withMetadata,
-          "Q", baton->quality, "optimize_coding", TRUE, "no_subsample", baton->withoutChromaSubsampling,
-#if (VIPS_MAJOR_VERSION >= 8)
+        if (vips_jpegsave(
+          image, baton->output.data(),
+          "strip", !baton->withMetadata,
+          "Q", baton->quality,
+          "optimize_coding", TRUE,
+          "no_subsample", baton->withoutChromaSubsampling,
          "trellis_quant", baton->trellisQuantisation,
          "overshoot_deringing", baton->overshootDeringing,
          "optimize_scans", baton->optimiseScans,
-#endif
-          "interlace", baton->progressive, NULL)) {
+          "interlace", baton->progressive,
+          nullptr
+        )) {
          return Error();
        }
        baton->outputFormat = "jpeg";
      } else if (outputPng || (matchInput && inputImageType == ImageType::PNG)) {
-#if (VIPS_MAJOR_VERSION >= 8 || (VIPS_MAJOR_VERSION >= 7 && VIPS_MINOR_VERSION >= 42))
-        // Select PNG row filter
-        int filter = baton->withoutAdaptiveFiltering ? VIPS_FOREIGN_PNG_FILTER_NONE : VIPS_FOREIGN_PNG_FILTER_ALL;
        // Write PNG to file
-        if (vips_pngsave(image, baton->output.c_str(), "strip", !baton->withMetadata,
-          "compression", baton->compressionLevel, "interlace", baton->progressive, "filter", filter, NULL)) {
+        if (vips_pngsave(
+          image, baton->output.data(),
+          "strip", !baton->withMetadata,
+          "compression", baton->compressionLevel,
+          "interlace", baton->progressive,
+          "filter", baton->withoutAdaptiveFiltering ? VIPS_FOREIGN_PNG_FILTER_NONE : VIPS_FOREIGN_PNG_FILTER_ALL,
+          nullptr
+        )) {
          return Error();
        }
-#else
-        // Write PNG to file
-        if (vips_pngsave(image, baton->output.c_str(), "strip", !baton->withMetadata,
-          "compression", baton->compressionLevel, "interlace", baton->progressive, NULL)) {
-          return Error();
-        }
-#endif
        baton->outputFormat = "png";
      } else if (outputWebp || (matchInput && inputImageType == ImageType::WEBP)) {
        // Write WEBP to file
-        if (vips_webpsave(image, baton->output.c_str(), "strip", !baton->withMetadata,
-          "Q", baton->quality, NULL)) {
+        if (vips_webpsave(
+          image, baton->output.data(),
+          "strip", !baton->withMetadata,
+          "Q", baton->quality,
+          nullptr
+        )) {
          return Error();
        }
        baton->outputFormat = "webp";
      } else if (outputTiff || (matchInput && inputImageType == ImageType::TIFF)) {
        // Write TIFF to file
-        if (vips_tiffsave(image, baton->output.c_str(), "strip", !baton->withMetadata,
-          "compression", VIPS_FOREIGN_TIFF_COMPRESSION_JPEG, "Q", baton->quality, NULL)) {
+        if (vips_tiffsave(
+          image, baton->output.data(),
+          "strip", !baton->withMetadata,
+          "compression", VIPS_FOREIGN_TIFF_COMPRESSION_JPEG,
+          "Q", baton->quality,
+          nullptr
+        )) {
          return Error();
        }
        baton->outputFormat = "tiff";
      } else if (outputDz) {
        // Write DZ to file
-        if (vips_dzsave(image, baton->output.c_str(), "strip", !baton->withMetadata,
-            "tile_size", baton->tileSize, "overlap", baton->tileOverlap, NULL)) {
+        if (vips_dzsave(
+          image, baton->output.data(),
+          "strip", !baton->withMetadata,
+          "tile_size", baton->tileSize,
+          "overlap", baton->tileOverlap,
+          nullptr
+        )) {
          return Error();
        }
        baton->outputFormat = "dz";
@@ -984,10 +1020,10 @@ class PipelineWorker : public AsyncWorker {
  void HandleOKCallback () {
    HandleScope();

-    Local<Value> argv[3] = { Null(), Null(),  Null() };
+    Local<Value> argv[3] = { Null(), Null(), Null() };
    if (!baton->err.empty()) {
      // Error
-      argv[0] = Nan::Error(baton->err.c_str());
+      argv[0] = Nan::Error(baton->err.data());
    } else {
      int width = baton->width;
      int height = baton->height;
@@ -1006,23 +1042,27 @@ class PipelineWorker : public AsyncWorker {
      Set(info, New("height").ToLocalChecked(), New<Uint32>(static_cast<uint32_t>(height)));

      if (baton->bufferOutLength > 0) {
-        // Copy data to new Buffer
-        argv[1] = CopyBuffer(static_cast<char*>(baton->bufferOut), baton->bufferOutLength).ToLocalChecked();
-        // bufferOut was allocated via g_malloc
-        g_free(baton->bufferOut);
+        // Pass ownership of output data to Buffer instance
+        argv[1] = NewBuffer(
+          static_cast<char*>(baton->bufferOut), baton->bufferOutLength, FreeCallback, nullptr
+        ).ToLocalChecked();
        // Add buffer size to info
        Set(info, New("size").ToLocalChecked(), New<Uint32>(static_cast<uint32_t>(baton->bufferOutLength)));
        argv[2] = info;
      } else {
        // Add file size to info
        GStatBuf st;
-        g_stat(baton->output.c_str(), &st);
+        g_stat(baton->output.data(), &st);
        Set(info, New("size").ToLocalChecked(), New<Uint32>(static_cast<uint32_t>(st.st_size)));
        argv[1] = info;
      }
    }
+
+    // Dispose of Persistent wrapper around input Buffer so it can be garbage collected
+    if (baton->bufferInLength > 0) {
+      GetFromPersistent("bufferIn");
+    }
    delete baton;
-    // to here

    // Decrement processing task counter
    g_atomic_int_dec_and_test(&counterProcess);
@@ -1169,12 +1209,11 @@ NAN_METHOD(pipeline) {
    To<bool>(Get(options, New("sequentialRead").ToLocalChecked()).ToLocalChecked()).FromJust() ?
    VIPS_ACCESS_SEQUENTIAL : VIPS_ACCESS_RANDOM;
  // Input Buffer object
+  Local<Object> bufferIn;
  if (node::Buffer::HasInstance(Get(options, New("bufferIn").ToLocalChecked()).ToLocalChecked())) {
-    Local<Object> buffer = Get(options, New("bufferIn").ToLocalChecked()).ToLocalChecked().As<Object>();
-    // Take a copy of the input Buffer to avoid problems with V8 heap compaction
-    baton->bufferInLength = node::Buffer::Length(buffer);
-    baton->bufferIn = new char[baton->bufferInLength];
-    memcpy(baton->bufferIn, node::Buffer::Data(buffer), baton->bufferInLength);
+    bufferIn = Get(options, New("bufferIn").ToLocalChecked()).ToLocalChecked().As<Object>();
+    baton->bufferInLength = node::Buffer::Length(bufferIn);
+    baton->bufferIn = node::Buffer::Data(bufferIn);
  }
  // ICC profile to use when input CMYK image has no embedded profile
  baton->iccProfilePath = *Utf8String(Get(options, New("iccProfilePath").ToLocalChecked()).ToLocalChecked());
@@ -1218,10 +1257,12 @@ NAN_METHOD(pipeline) {
  baton->interpolator = *Utf8String(Get(options, New("interpolator").ToLocalChecked()).ToLocalChecked());
  // Operators
  baton->flatten = To<bool>(Get(options, New("flatten").ToLocalChecked()).ToLocalChecked()).FromJust();
+  baton->negate = To<bool>(Get(options, New("negate").ToLocalChecked()).ToLocalChecked()).FromJust();
  baton->blurSigma = To<double>(Get(options, New("blurSigma").ToLocalChecked()).ToLocalChecked()).FromJust();
  baton->sharpenRadius = To<int32_t>(Get(options, New("sharpenRadius").ToLocalChecked()).ToLocalChecked()).FromJust();
  baton->sharpenFlat = To<double>(Get(options, New("sharpenFlat").ToLocalChecked()).ToLocalChecked()).FromJust();
  baton->sharpenJagged = To<double>(Get(options, New("sharpenJagged").ToLocalChecked()).ToLocalChecked()).FromJust();
+  baton->threshold = To<int32_t>(Get(options, New("threshold").ToLocalChecked()).ToLocalChecked()).FromJust();
  baton->gamma = To<int32_t>(Get(options, New("gamma").ToLocalChecked()).ToLocalChecked()).FromJust();
  baton->greyscale = To<bool>(Get(options, New("greyscale").ToLocalChecked()).ToLocalChecked()).FromJust();
  baton->normalize = To<bool>(Get(options, New("normalize").ToLocalChecked()).ToLocalChecked()).FromJust();
@@ -1249,11 +1290,10 @@ NAN_METHOD(pipeline) {

  // Join queue for worker thread
  Callback *callback = new Callback(info[1].As<Function>());
-  AsyncQueueWorker(new PipelineWorker(callback, baton, queueListener));
+  AsyncQueueWorker(new PipelineWorker(callback, baton, queueListener, bufferIn));

  // Increment queued task counter
  g_atomic_int_inc(&counterQueue);
  Local<Value> queueLength[1] = { New<Uint32>(counterQueue) };
  queueListener->Call(1, queueLength);
 }
-
--- a/src/utilities.cc
+++ b/src/utilities.cc
@@ -1,3 +1,4 @@
+#include <cmath>
 #include <node.h>
 #include <vips/vips.h>

@@ -7,11 +8,12 @@
 #include "operations.h"
 #include "utilities.h"

-using v8::Local;
-using v8::Object;
-using v8::Number;
-using v8::String;
 using v8::Boolean;
+using v8::Integer;
+using v8::Local;
+using v8::Number;
+using v8::Object;
+using v8::String;

 using Nan::HandleScope;
 using Nan::New;
@@ -38,10 +40,16 @@ NAN_METHOD(cache) {

  // Get cache statistics
  Local<Object> cache = New<Object>();
-  Set(cache, New("current").ToLocalChecked(), New<Number>(vips_tracked_get_mem() / 1048576));
-  Set(cache, New("high").ToLocalChecked(), New<Number>(vips_tracked_get_mem_highwater() / 1048576));
-  Set(cache, New("memory").ToLocalChecked(), New<Number>(vips_cache_get_max_mem() / 1048576));
-  Set(cache, New("items").ToLocalChecked(), New<Number>(vips_cache_get_max()));
+  Set(cache, New("current").ToLocalChecked(),
+    New<Integer>(static_cast<int>(round(vips_tracked_get_mem() / 1048576)))
+  );
+  Set(cache, New("high").ToLocalChecked(),
+    New<Integer>(static_cast<int>(round(vips_tracked_get_mem_highwater() / 1048576)))
+  );
+  Set(cache, New("memory").ToLocalChecked(),
+    New<Integer>(static_cast<int>(round(vips_cache_get_max_mem() / 1048576)))
+  );
+  Set(cache, New("items").ToLocalChecked(), New<Integer>(vips_cache_get_max()));
  info.GetReturnValue().Set(cache);
 }

@@ -56,7 +64,7 @@ NAN_METHOD(concurrency) {
    vips_concurrency_set(To<int32_t>(info[0]).FromJust());
  }
  // Get concurrency
-  info.GetReturnValue().Set(New<Number>(vips_concurrency_get()));
+  info.GetReturnValue().Set(New<Integer>(vips_concurrency_get()));
 }

 /*
@@ -68,8 +76,8 @@ NAN_METHOD(counters) {

  HandleScope();
  Local<Object> counters = New<Object>();
-  Set(counters, New("queue").ToLocalChecked(), New<Number>(counterQueue));
-  Set(counters, New("process").ToLocalChecked(), New<Number>(counterProcess));
+  Set(counters, New("queue").ToLocalChecked(), New<Integer>(counterQueue));
+  Set(counters, New("process").ToLocalChecked(), New<Integer>(counterProcess));
  info.GetReturnValue().Set(counters);
 }

@@ -157,7 +165,6 @@ NAN_METHOD(format) {
  between two images of the same dimensions and number of channels.
 */
 NAN_METHOD(_maxColourDistance) {
-  using sharp::Premultiply;
  using sharp::DetermineImageType;
  using sharp::ImageType;
  using sharp::InitImage;
@@ -169,11 +176,11 @@ NAN_METHOD(_maxColourDistance) {
  VipsObject *hook = reinterpret_cast<VipsObject*>(vips_image_new());

  // Open input files
-  VipsImage *image1 = NULL;
+  VipsImage *image1 = nullptr;
  ImageType imageType1 = DetermineImageType(*Utf8String(info[0]));
  if (imageType1 != ImageType::UNKNOWN) {
    image1 = InitImage(*Utf8String(info[0]), VIPS_ACCESS_SEQUENTIAL);
-    if (image1 == NULL) {
+    if (image1 == nullptr) {
      g_object_unref(hook);
      return ThrowError("Input file 1 has corrupt header");
    } else {
@@ -183,11 +190,11 @@ NAN_METHOD(_maxColourDistance) {
    g_object_unref(hook);
    return ThrowError("Input file 1 is of an unsupported image format");
  }
-  VipsImage *image2 = NULL;
+  VipsImage *image2 = nullptr;
  ImageType imageType2 = DetermineImageType(*Utf8String(info[1]));
  if (imageType2 != ImageType::UNKNOWN) {
    image2 = InitImage(*Utf8String(info[1]), VIPS_ACCESS_SEQUENTIAL);
-    if (image2 == NULL) {
+    if (image2 == nullptr) {
      g_object_unref(hook);
      return ThrowError("Input file 2 has corrupt header");
    } else {
@@ -212,13 +219,13 @@ NAN_METHOD(_maxColourDistance) {
  // Premultiply and remove alpha
  if (HasAlpha(image1)) {
    VipsImage *imagePremultiplied1;
-    if (Premultiply(hook, image1, &imagePremultiplied1)) {
+    if (vips_premultiply(image1, &imagePremultiplied1, nullptr)) {
      g_object_unref(hook);
      return ThrowError(vips_error_buffer());
    }
    vips_object_local(hook, imagePremultiplied1);
    VipsImage *imagePremultipliedNoAlpha1;
-    if (vips_extract_band(image1, &imagePremultipliedNoAlpha1, 1, "n", image1->Bands - 1, NULL)) {
+    if (vips_extract_band(image1, &imagePremultipliedNoAlpha1, 1, "n", image1->Bands - 1, nullptr)) {
      g_object_unref(hook);
      return ThrowError(vips_error_buffer());
    }
@@ -227,13 +234,13 @@ NAN_METHOD(_maxColourDistance) {
  }
  if (HasAlpha(image2)) {
    VipsImage *imagePremultiplied2;
-    if (Premultiply(hook, image2, &imagePremultiplied2)) {
+    if (vips_premultiply(image2, &imagePremultiplied2, nullptr)) {
      g_object_unref(hook);
      return ThrowError(vips_error_buffer());
    }
    vips_object_local(hook, imagePremultiplied2);
    VipsImage *imagePremultipliedNoAlpha2;
-    if (vips_extract_band(image2, &imagePremultipliedNoAlpha2, 1, "n", image2->Bands - 1, NULL)) {
+    if (vips_extract_band(image2, &imagePremultipliedNoAlpha2, 1, "n", image2->Bands - 1, nullptr)) {
      g_object_unref(hook);
      return ThrowError(vips_error_buffer());
    }
@@ -242,14 +249,14 @@ NAN_METHOD(_maxColourDistance) {
  }
  // Calculate colour distance
  VipsImage *difference;
-  if (vips_dE00(image1, image2, &difference, NULL)) {
+  if (vips_dE00(image1, image2, &difference, nullptr)) {
    g_object_unref(hook);
    return ThrowError(vips_error_buffer());
  }
  vips_object_local(hook, difference);
  // Extract maximum distance
  double maxColourDistance;
-  if (vips_max(difference, &maxColourDistance, NULL)) {
+  if (vips_max(difference, &maxColourDistance, nullptr)) {
    g_object_unref(hook);
    return ThrowError(vips_error_buffer());
  }
--- a/test/bench/package.json
+++ b/test/bench/package.json
@@ -8,14 +8,14 @@
    "test": "node perf && node random && node parallel"
  },
  "devDependencies": {
-    "async": "^1.4.2",
+    "async": "^1.5.0",
    "benchmark": "^1.0.0",
-    "gm": "^1.20.0",
+    "gm": "^1.21.0",
    "imagemagick": "^0.1.3",
-    "imagemagick-native": "^1.8.0",
-    "jimp": "^0.2.8",
+    "imagemagick-native": "elad/node-imagemagick-native",
+    "jimp": "^0.2.19",
    "lwip": "^0.0.8",
-    "semver": "^5.0.3"
+    "semver": "^5.1.0"
  },
  "license": "Apache-2.0",
  "engines": {
--- a/test/bench/parallel.js
+++ b/test/bench/parallel.js
@@ -1,5 +1,7 @@
 'use strict';

+process.env.UV_THREADPOOL_SIZE = 64;
+
 var assert = require('assert');
 var async = require('async');

@@ -15,7 +17,7 @@ var timer = setInterval(function() {
  console.dir(sharp.counters());
 }, 100);

-async.mapSeries([1, 1, 2, 4, 8, 16, 32, 64, 128], function(parallelism, next) {
+async.mapSeries([1, 1, 2, 4, 8, 16, 32, 64], function(parallelism, next) {
  var start = new Date().getTime();
  async.times(parallelism,
    function(id, callback) {
--- a/test/bench/perf.js
+++ b/test/bench/perf.js
--- a/test/bench/random.js
+++ b/test/bench/random.js
--- a/test/fixtures/Landscape_1.jpg
+++ b/test/fixtures/Landscape_1.jpg
--- a/test/fixtures/Landscape_2.jpg
+++ b/test/fixtures/Landscape_2.jpg
--- a/test/fixtures/Landscape_3.jpg
+++ b/test/fixtures/Landscape_3.jpg
--- a/test/fixtures/Landscape_4.jpg
+++ b/test/fixtures/Landscape_4.jpg
--- a/test/fixtures/Landscape_5.jpg
+++ b/test/fixtures/Landscape_5.jpg
--- a/test/fixtures/Landscape_6.jpg
+++ b/test/fixtures/Landscape_6.jpg
--- a/test/fixtures/Landscape_7.jpg
+++ b/test/fixtures/Landscape_7.jpg
--- a/test/fixtures/Landscape_8.jpg
+++ b/test/fixtures/Landscape_8.jpg
--- a/test/fixtures/Portrait_1.jpg
+++ b/test/fixtures/Portrait_1.jpg
--- a/test/fixtures/Portrait_2.jpg
+++ b/test/fixtures/Portrait_2.jpg
--- a/test/fixtures/Portrait_3.jpg
+++ b/test/fixtures/Portrait_3.jpg
--- a/test/fixtures/Portrait_4.jpg
+++ b/test/fixtures/Portrait_4.jpg
--- a/test/fixtures/Portrait_5.jpg
+++ b/test/fixtures/Portrait_5.jpg
--- a/test/fixtures/Portrait_6.jpg
+++ b/test/fixtures/Portrait_6.jpg
--- a/test/fixtures/Portrait_7.jpg
+++ b/test/fixtures/Portrait_7.jpg
--- a/test/fixtures/Portrait_8.jpg
+++ b/test/fixtures/Portrait_8.jpg
--- a/test/fixtures/expected/extract-resize.jpg
+++ b/test/fixtures/expected/extract-resize.jpg
--- a/test/fixtures/expected/extract-rotate.jpg
+++ b/test/fixtures/expected/extract-rotate.jpg
--- a/test/fixtures/expected/flatten-rgb16-orange.jpg
+++ b/test/fixtures/expected/flatten-rgb16-orange.jpg
--- a/test/fixtures/expected/gamma-0.0.jpg
+++ b/test/fixtures/expected/gamma-0.0.jpg
--- a/test/fixtures/expected/negate-alpha.png
+++ b/test/fixtures/expected/negate-alpha.png
--- a/test/fixtures/expected/negate-trans.png
+++ b/test/fixtures/expected/negate-trans.png
--- a/test/fixtures/expected/negate-trans.webp
+++ b/test/fixtures/expected/negate-trans.webp
--- a/test/fixtures/expected/negate.jpg
+++ b/test/fixtures/expected/negate.jpg
--- a/test/fixtures/expected/negate.png
+++ b/test/fixtures/expected/negate.png
--- a/test/fixtures/expected/negate.webp
+++ b/test/fixtures/expected/negate.webp
--- a/test/fixtures/expected/rotate-extract.jpg
+++ b/test/fixtures/expected/rotate-extract.jpg
--- a/test/fixtures/expected/svg.png
+++ b/test/fixtures/expected/svg.png
--- a/test/fixtures/expected/threshold-1.jpg
+++ b/test/fixtures/expected/threshold-1.jpg
--- a/test/fixtures/expected/threshold-128-alpha.png
+++ b/test/fixtures/expected/threshold-128-alpha.png
--- a/test/fixtures/expected/threshold-128-transparency.png
+++ b/test/fixtures/expected/threshold-128-transparency.png
--- a/test/fixtures/expected/threshold-128-transparency.webp
+++ b/test/fixtures/expected/threshold-128-transparency.webp
--- a/test/fixtures/expected/threshold-128.jpg
+++ b/test/fixtures/expected/threshold-128.jpg
--- a/test/fixtures/expected/threshold-40.jpg
+++ b/test/fixtures/expected/threshold-40.jpg
--- a/test/fixtures/index.js
+++ b/test/fixtures/index.js
@@ -71,6 +71,7 @@ module.exports = {
  inputPngWithTransparency: getPath('blackbug.png'), // public domain
  inputPngWithGreyAlpha: getPath('grey-8bit-alpha.png'),
  inputPngWithOneColor: getPath('2x2_fdcce6.png'),
+  inputPngWithTransparency16bit: getPath('tbgn2c16.png'), // http://www.schaik.com/pngsuite/tbgn2c16.png
  inputPngOverlayLayer0: getPath('alpha-layer-0-background.png'),
  inputPngOverlayLayer1: getPath('alpha-layer-1-fill.png'),
  inputPngOverlayLayer2: getPath('alpha-layer-2-ink.png'),
--- a/test/fixtures/tbgn2c16.png
+++ b/test/fixtures/tbgn2c16.png
--- a/test/interpolators/README.md
+++ b/test/interpolators/README.md
@@ -0,0 +1,48 @@
+# Interpolators
+
+[Photo](https://www.flickr.com/photos/aotaro/21978966091) by
+[aotaro](https://www.flickr.com/photos/aotaro/) is licensed under
+[CC BY 2.0](https://creativecommons.org/licenses/by/2.0/).
+
+The following examples take the 4608x3072px original image
+and resize to 480x320px using various interpolators.
+
+To fetch the original 4608x3072px image and
+generate the interpolator sample images:
+
+```sh
+curl -O https://farm6.staticflickr.com/5682/21978966091_b421afe866_o.jpg
+node generate.js
+```
+
+## Nearest neighbour
+
+![Nearest neighbour interpolation](nearest.jpg)
+
+## Bilinear
+
+![Bilinear interpolation](bilinear.jpg)
+
+## Bicubic
+
+![Bicubic interpolation](bicubic.jpg)
+
+## Locally bounded bicubic
+
+![Locally bounded bicubic interpolation](lbb.jpg)
+
+## Vertex-split quadratic b-splines (VSQBS)
+
+![Vertex-split quadratic b-splines interpolation](vsqbs.jpg)
+
+## Nohalo
+
+![Nohalo interpolation](nohalo.jpg)
+
+## GraphicsMagick
+
+![GraphicsMagick](gm.jpg)
+
+```sh
+gm convert 21978966091_b421afe866_o.jpg -resize 480x320^ -gravity center -extent 480x320 -quality 95 -strip -define jpeg:optimize-coding=true gm.jpg
+```
--- a/test/interpolators/bicubic.jpg
+++ b/test/interpolators/bicubic.jpg
--- a/test/interpolators/bilinear.jpg
+++ b/test/interpolators/bilinear.jpg
--- a/test/interpolators/generate.js
+++ b/test/interpolators/generate.js
@@ -0,0 +1,11 @@
+'use strict';
+
+['nearest', 'bilinear', 'bicubic', 'vsqbs', 'lbb', 'nohalo'].forEach(function(interpolator) {
+  require('../../')('21978966091_b421afe866_o.jpg')
+    .resize(480, 320)
+    .interpolateWith(interpolator)
+    .quality(95)
+    .toFile(interpolator + '.jpg', function(err) {
+      if (err) throw err;
+    });
+});
--- a/test/interpolators/gm.jpg
+++ b/test/interpolators/gm.jpg
--- a/test/interpolators/lbb.jpg
+++ b/test/interpolators/lbb.jpg
--- a/test/interpolators/nearest.jpg
+++ b/test/interpolators/nearest.jpg
--- a/test/interpolators/nohalo.jpg
+++ b/test/interpolators/nohalo.jpg
--- a/test/interpolators/vsqbs.jpg
+++ b/test/interpolators/vsqbs.jpg
--- a/test/leak/sharp.supp
+++ b/test/leak/sharp.supp
@@ -278,11 +278,25 @@
  ...
  fun:vips__magick_read_header
 }
+{
+  cond_magick_is_palette_image
+  Memcheck:Cond
+  fun:IsPaletteImage
+  ...
+  fun:get_bands
+}
+{
+  value_magick_is_palette_image
+  Memcheck:Value8
+  fun:IsPaletteImage
+  ...
+  fun:get_bands
+}

 # glib g_file_read_link
 # https://github.com/GNOME/glib/commit/49a5d0f6f2aed99cd78f25655f137f4448e47d92
 {
-  leak_magick
+  leak_g_file_read_link
  Memcheck:Leak
  match-leak-kinds: definite,indirect,possible
  ...
--- a/test/unit/alpha.js
+++ b/test/unit/alpha.js
@@ -46,6 +46,19 @@ describe('Alpha transparency', function() {
      });
  });

+  it('Flatten 16-bit PNG with transparency to orange', function(done) {
+    sharp(fixtures.inputPngWithTransparency16bit)
+      .flatten()
+      .background({r: 255, g: 102, b: 0})
+      .toBuffer(function(err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(true, info.size > 0);
+        assert.strictEqual(32, info.width);
+        assert.strictEqual(32, info.height);
+        fixtures.assertSimilar(fixtures.expected('flatten-rgb16-orange.jpg'), data, done);
+      });
+  });
+
  it('Do not flatten', function(done) {
    sharp(fixtures.inputPngWithTransparency)
      .flatten(false)
--- a/test/unit/blur.js
+++ b/test/unit/blur.js
--- a/test/unit/clone.js
+++ b/test/unit/clone.js
--- a/test/unit/colourspace.js
+++ b/test/unit/colourspace.js
--- a/test/unit/cpplint.js
+++ b/test/unit/cpplint.js
--- a/test/unit/crop.js
+++ b/test/unit/crop.js
--- a/test/unit/embed.js
+++ b/test/unit/embed.js
--- a/test/unit/extract.js
+++ b/test/unit/extract.js
@@ -8,10 +8,33 @@ var fixtures = require('../fixtures');
 sharp.cache(0);

 describe('Partial image extraction', function() {
+  describe('using the legacy extract(top,left,width,height) syntax', function () {
+    it('JPEG', function(done) {
+      sharp(fixtures.inputJpg)
+        .extract(2, 2, 20, 20)
+        .toBuffer(function(err, data, info) {
+          if (err) throw err;
+          assert.strictEqual(20, info.width);
+          assert.strictEqual(20, info.height);
+          fixtures.assertSimilar(fixtures.expected('extract.jpg'), data, done);
+        });
+    });
+
+    it('PNG', function(done) {
+      sharp(fixtures.inputPng)
+        .extract(300, 200, 400, 200)
+        .toBuffer(function(err, data, info) {
+          if (err) throw err;
+          assert.strictEqual(400, info.width);
+          assert.strictEqual(200, info.height);
+          fixtures.assertSimilar(fixtures.expected('extract.png'), data, done);
+      });
+    });
+  });

  it('JPEG', function(done) {
    sharp(fixtures.inputJpg)
-      .extract(2, 2, 20, 20)
+      .extract({ left: 2, top: 2, width: 20, height: 20 })
      .toBuffer(function(err, data, info) {
        if (err) throw err;
        assert.strictEqual(20, info.width);
@@ -22,7 +45,7 @@ describe('Partial image extraction', function() {

  it('PNG', function(done) {
    sharp(fixtures.inputPng)
-      .extract(300, 200, 400, 200)
+      .extract({ left: 200, top: 300, width: 400, height: 200 })
      .toBuffer(function(err, data, info) {
        if (err) throw err;
        assert.strictEqual(400, info.width);
@@ -34,7 +57,7 @@ describe('Partial image extraction', function() {
  if (sharp.format.webp.output.file) {
    it('WebP', function(done) {
      sharp(fixtures.inputWebP)
-        .extract(50, 100, 125, 200)
+        .extract({ left: 100, top: 50, width: 125, height: 200 })
        .toBuffer(function(err, data, info) {
          if (err) throw err;
          assert.strictEqual(125, info.width);
@@ -46,7 +69,7 @@ describe('Partial image extraction', function() {

  it('TIFF', function(done) {
    sharp(fixtures.inputTiff)
-      .extract(63, 34, 341, 529)
+      .extract({ left: 34, top: 63, width: 341, height: 529 })
      .jpeg()
      .toBuffer(function(err, data, info) {
        if (err) throw err;
@@ -58,7 +81,7 @@ describe('Partial image extraction', function() {

  it('Before resize', function(done) {
    sharp(fixtures.inputJpg)
-      .extract(10, 10, 10, 500, 500)
+      .extract({ left: 10, top: 10, width: 10, height: 500 })
      .resize(100, 100)
      .toBuffer(function(err, data, info) {
        if (err) throw err;
@@ -72,7 +95,7 @@ describe('Partial image extraction', function() {
    sharp(fixtures.inputJpg)
      .resize(500, 500)
      .crop(sharp.gravity.north)
-      .extract(10, 10, 100, 100)
+      .extract({ left: 10, top: 10, width: 100, height: 100 })
      .toBuffer(function(err, data, info) {
        if (err) throw err;
        assert.strictEqual(100, info.width);
@@ -83,10 +106,10 @@ describe('Partial image extraction', function() {

  it('Before and after resize and crop', function(done) {
    sharp(fixtures.inputJpg)
-      .extract(0, 0, 700, 700)
+      .extract({ left: 0, top: 0, width: 700, height: 700 })
      .resize(500, 500)
      .crop(sharp.gravity.north)
-      .extract(10, 10, 100, 100)
+      .extract({ left: 10, top: 10, width: 100, height: 100 })
      .toBuffer(function(err, data, info) {
        if (err) throw err;
        assert.strictEqual(100, info.width);
@@ -96,30 +119,55 @@ describe('Partial image extraction', function() {
  });

  it('Extract then rotate', function(done) {
-    sharp(fixtures.inputJpg)
-      .extract(10, 10, 100, 100)
+    sharp(fixtures.inputPngWithGreyAlpha)
+      .extract({ left: 20, top: 10, width: 380, height: 280 })
      .rotate(90)
      .toBuffer(function(err, data, info) {
        if (err) throw err;
-        assert.strictEqual(100, info.width);
-        assert.strictEqual(100, info.height);
+        assert.strictEqual(280, info.width);
+        assert.strictEqual(380, info.height);
        fixtures.assertSimilar(fixtures.expected('extract-rotate.jpg'), data, done);
      });
  });

  it('Rotate then extract', function(done) {
-    sharp(fixtures.inputJpg)
+    sharp(fixtures.inputPngWithGreyAlpha)
      .rotate(90)
-      .extract(10, 10, 100, 100)
+      .extract({ left: 20, top: 10, width: 280, height: 380 })
      .toBuffer(function(err, data, info) {
        if (err) throw err;
-        assert.strictEqual(100, info.width);
-        assert.strictEqual(100, info.height);
+        assert.strictEqual(280, info.width);
+        assert.strictEqual(380, info.height);
        fixtures.assertSimilar(fixtures.expected('rotate-extract.jpg'), data, done);
      });
  });

  describe('Invalid parameters', function() {
+    describe('using the legacy extract(top,left,width,height) syntax', function () {
+      it('String top', function() {
+        assert.throws(function() {
+          sharp(fixtures.inputJpg).extract('spoons', 10, 10, 10);
+        });
+      });
+
+      it('Non-integral left', function() {
+        assert.throws(function() {
+          sharp(fixtures.inputJpg).extract(10, 10.2, 10, 10);
+        });
+      });
+
+      it('Negative width - negative', function() {
+        assert.throws(function() {
+          sharp(fixtures.inputJpg).extract(10, 10, -10, 10);
+        });
+      });
+
+      it('Null height', function() {
+        assert.throws(function() {
+          sharp(fixtures.inputJpg).extract(10, 10, 10, null);
+        });
+      });
+    });

    it('Undefined', function() {
      assert.throws(function() {
@@ -129,27 +177,26 @@ describe('Partial image extraction', function() {

    it('String top', function() {
      assert.throws(function() {
-        sharp(fixtures.inputJpg).extract('spoons', 10, 10, 10);
+        sharp(fixtures.inputJpg).extract({ left: 10, top: 'spoons', width: 10, height: 10 });
      });
    });

    it('Non-integral left', function() {
      assert.throws(function() {
-        sharp(fixtures.inputJpg).extract(10, 10.2, 10, 10);
+        sharp(fixtures.inputJpg).extract({ left: 10.2, top: 10, width: 10, height: 10 });
      });
    });

    it('Negative width - negative', function() {
      assert.throws(function() {
-        sharp(fixtures.inputJpg).extract(10, 10, -10, 10);
+        sharp(fixtures.inputJpg).extract({ left: 10, top: 10, width: -10, height: 10 });
      });
    });

    it('Null height', function() {
      assert.throws(function() {
-        sharp(fixtures.inputJpg).extract(10, 10, 10, null);
+        sharp(fixtures.inputJpg).extract({ left: 10, top: 10, width: 10, height: null });
      });
    });
-
  });
 });
--- a/test/unit/gamma.js
+++ b/test/unit/gamma.js
@@ -16,7 +16,7 @@ describe('Gamma correction', function() {
        assert.strictEqual('jpeg', info.format);
        assert.strictEqual(129, info.width);
        assert.strictEqual(111, info.height);
-        fixtures.assertSimilar(fixtures.expected('gamma-0.0.jpg'), data, {threshold: 12}, done);
+        fixtures.assertSimilar(fixtures.expected('gamma-0.0.jpg'), data, done);
      });
  });

--- a/test/unit/interpolation.js
+++ b/test/unit/interpolation.js
--- a/test/unit/io.js
+++ b/test/unit/io.js
@@ -3,8 +3,6 @@
 var fs = require('fs');
 var assert = require('assert');

-var semver = require('semver');
-
 var sharp = require('../../index');
 var fixtures = require('../fixtures');

@@ -483,37 +481,34 @@ describe('Input/output', function() {
      done();
    });

-    if (semver.gte(sharp.libvipsVersion(), '7.42.0')) {
-      it('withoutAdaptiveFiltering generates smaller file [libvips ' + sharp.libvipsVersion() + '>=7.42.0]', function(done) {
-        // First generate with adaptive filtering
-        sharp(fixtures.inputPng)
-          .resize(320, 240)
-          .withoutAdaptiveFiltering(false)
-          .toBuffer(function(err, adaptiveData, adaptiveInfo) {
-            if (err) throw err;
-            assert.strictEqual(true, adaptiveData.length > 0);
-            assert.strictEqual(adaptiveData.length, adaptiveInfo.size);
-            assert.strictEqual('png', adaptiveInfo.format);
-            assert.strictEqual(320, adaptiveInfo.width);
-            assert.strictEqual(240, adaptiveInfo.height);
-            // Then generate without
-            sharp(fixtures.inputPng)
-              .resize(320, 240)
-              .withoutAdaptiveFiltering()
-              .toBuffer(function(err, withoutAdaptiveData, withoutAdaptiveInfo) {
-                if (err) throw err;
-                assert.strictEqual(true, withoutAdaptiveData.length > 0);
-                assert.strictEqual(withoutAdaptiveData.length, withoutAdaptiveInfo.size);
-                assert.strictEqual('png', withoutAdaptiveInfo.format);
-                assert.strictEqual(320, withoutAdaptiveInfo.width);
-                assert.strictEqual(240, withoutAdaptiveInfo.height);
-                assert.strictEqual(true, withoutAdaptiveData.length < adaptiveData.length);
-                done();
-              });
-          });
-      });
-    }
-
+    it('withoutAdaptiveFiltering generates smaller file', function(done) {
+      // First generate with adaptive filtering
+      sharp(fixtures.inputPng)
+        .resize(320, 240)
+        .withoutAdaptiveFiltering(false)
+        .toBuffer(function(err, adaptiveData, adaptiveInfo) {
+          if (err) throw err;
+          assert.strictEqual(true, adaptiveData.length > 0);
+          assert.strictEqual(adaptiveData.length, adaptiveInfo.size);
+          assert.strictEqual('png', adaptiveInfo.format);
+          assert.strictEqual(320, adaptiveInfo.width);
+          assert.strictEqual(240, adaptiveInfo.height);
+          // Then generate without
+          sharp(fixtures.inputPng)
+            .resize(320, 240)
+            .withoutAdaptiveFiltering()
+            .toBuffer(function(err, withoutAdaptiveData, withoutAdaptiveInfo) {
+              if (err) throw err;
+              assert.strictEqual(true, withoutAdaptiveData.length > 0);
+              assert.strictEqual(withoutAdaptiveData.length, withoutAdaptiveInfo.size);
+              assert.strictEqual('png', withoutAdaptiveInfo.format);
+              assert.strictEqual(320, withoutAdaptiveInfo.width);
+              assert.strictEqual(240, withoutAdaptiveInfo.height);
+              assert.strictEqual(true, withoutAdaptiveData.length < adaptiveData.length);
+              done();
+            });
+        });
+    });
  });

  it('Without chroma subsampling generates larger file', function(done) {
@@ -545,109 +540,110 @@ describe('Input/output', function() {
      });
  });

-  if (semver.gte(sharp.libvipsVersion(), '8.0.0')) {
-    it('Trellis quantisation [libvips ' + sharp.libvipsVersion() + '>=8.0.0]', function(done) {
-      // First generate without
-      sharp(fixtures.inputJpg)
-        .resize(320, 240)
-        .trellisQuantisation(false)
-        .toBuffer(function(err, withoutData, withoutInfo) {
-          if (err) throw err;
-          assert.strictEqual(true, withoutData.length > 0);
-          assert.strictEqual(withoutData.length, withoutInfo.size);
-          assert.strictEqual('jpeg', withoutInfo.format);
-          assert.strictEqual(320, withoutInfo.width);
-          assert.strictEqual(240, withoutInfo.height);
-          // Then generate with
-          sharp(fixtures.inputJpg)
-            .resize(320, 240)
-            .trellisQuantization()
-            .toBuffer(function(err, withData, withInfo) {
-              if (err) throw err;
-              assert.strictEqual(true, withData.length > 0);
-              assert.strictEqual(withData.length, withInfo.size);
-              assert.strictEqual('jpeg', withInfo.format);
-              assert.strictEqual(320, withInfo.width);
-              assert.strictEqual(240, withInfo.height);
-              // Verify image is same (as mozjpeg may not be present) size or less
-              assert.strictEqual(true, withData.length <= withoutData.length);
-              done();
-            });
-        });
-    });
-    it('Overshoot deringing [libvips ' + sharp.libvipsVersion() + '>=8.0.0]', function(done) {
-      // First generate without
-      sharp(fixtures.inputJpg)
-        .resize(320, 240)
-        .overshootDeringing(false)
-        .toBuffer(function(err, withoutData, withoutInfo) {
-          if (err) throw err;
-          assert.strictEqual(true, withoutData.length > 0);
-          assert.strictEqual(withoutData.length, withoutInfo.size);
-          assert.strictEqual('jpeg', withoutInfo.format);
-          assert.strictEqual(320, withoutInfo.width);
-          assert.strictEqual(240, withoutInfo.height);
-          // Then generate with
-          sharp(fixtures.inputJpg)
-            .resize(320, 240)
-            .overshootDeringing()
-            .toBuffer(function(err, withData, withInfo) {
-              if (err) throw err;
-              assert.strictEqual(true, withData.length > 0);
-              assert.strictEqual(withData.length, withInfo.size);
-              assert.strictEqual('jpeg', withInfo.format);
-              assert.strictEqual(320, withInfo.width);
-              assert.strictEqual(240, withInfo.height);
-              done();
-            });
-        });
-    });
-    it('Optimise scans [libvips ' + sharp.libvipsVersion() + '>=8.0.0]', function(done) {
-      // First generate without
-      sharp(fixtures.inputJpg)
-        .resize(320, 240)
-        .optimiseScans(false)
-        .toBuffer(function(err, withoutData, withoutInfo) {
-          if (err) throw err;
-          assert.strictEqual(true, withoutData.length > 0);
-          assert.strictEqual(withoutData.length, withoutInfo.size);
-          assert.strictEqual('jpeg', withoutInfo.format);
-          assert.strictEqual(320, withoutInfo.width);
-          assert.strictEqual(240, withoutInfo.height);
-          // Then generate with
-          sharp(fixtures.inputJpg)
-            .resize(320, 240)
-            .optimizeScans()
-            .toBuffer(function(err, withData, withInfo) {
-              if (err) throw err;
-              assert.strictEqual(true, withData.length > 0);
-              assert.strictEqual(withData.length, withInfo.size);
-              assert.strictEqual('jpeg', withInfo.format);
-              assert.strictEqual(320, withInfo.width);
-              assert.strictEqual(240, withInfo.height);
-              // Verify image is of a different size (progressive output even without mozjpeg)
-              assert.strictEqual(true, withData.length != withoutData.length);
-              done();
-            });
-        });
-    });
-  }
+  it('Trellis quantisation', function(done) {
+    // First generate without
+    sharp(fixtures.inputJpg)
+      .resize(320, 240)
+      .trellisQuantisation(false)
+      .toBuffer(function(err, withoutData, withoutInfo) {
+        if (err) throw err;
+        assert.strictEqual(true, withoutData.length > 0);
+        assert.strictEqual(withoutData.length, withoutInfo.size);
+        assert.strictEqual('jpeg', withoutInfo.format);
+        assert.strictEqual(320, withoutInfo.width);
+        assert.strictEqual(240, withoutInfo.height);
+        // Then generate with
+        sharp(fixtures.inputJpg)
+          .resize(320, 240)
+          .trellisQuantization()
+          .toBuffer(function(err, withData, withInfo) {
+            if (err) throw err;
+            assert.strictEqual(true, withData.length > 0);
+            assert.strictEqual(withData.length, withInfo.size);
+            assert.strictEqual('jpeg', withInfo.format);
+            assert.strictEqual(320, withInfo.width);
+            assert.strictEqual(240, withInfo.height);
+            // Verify image is same (as mozjpeg may not be present) size or less
+            assert.strictEqual(true, withData.length <= withoutData.length);
+            done();
+          });
+      });
+  });
+
+  it('Overshoot deringing', function(done) {
+    // First generate without
+    sharp(fixtures.inputJpg)
+      .resize(320, 240)
+      .overshootDeringing(false)
+      .toBuffer(function(err, withoutData, withoutInfo) {
+        if (err) throw err;
+        assert.strictEqual(true, withoutData.length > 0);
+        assert.strictEqual(withoutData.length, withoutInfo.size);
+        assert.strictEqual('jpeg', withoutInfo.format);
+        assert.strictEqual(320, withoutInfo.width);
+        assert.strictEqual(240, withoutInfo.height);
+        // Then generate with
+        sharp(fixtures.inputJpg)
+          .resize(320, 240)
+          .overshootDeringing()
+          .toBuffer(function(err, withData, withInfo) {
+            if (err) throw err;
+            assert.strictEqual(true, withData.length > 0);
+            assert.strictEqual(withData.length, withInfo.size);
+            assert.strictEqual('jpeg', withInfo.format);
+            assert.strictEqual(320, withInfo.width);
+            assert.strictEqual(240, withInfo.height);
+            done();
+          });
+      });
+  });
+
+  it('Optimise scans', function(done) {
+    // First generate without
+    sharp(fixtures.inputJpg)
+      .resize(320, 240)
+      .optimiseScans(false)
+      .toBuffer(function(err, withoutData, withoutInfo) {
+        if (err) throw err;
+        assert.strictEqual(true, withoutData.length > 0);
+        assert.strictEqual(withoutData.length, withoutInfo.size);
+        assert.strictEqual('jpeg', withoutInfo.format);
+        assert.strictEqual(320, withoutInfo.width);
+        assert.strictEqual(240, withoutInfo.height);
+        // Then generate with
+        sharp(fixtures.inputJpg)
+          .resize(320, 240)
+          .optimizeScans()
+          .toBuffer(function(err, withData, withInfo) {
+            if (err) throw err;
+            assert.strictEqual(true, withData.length > 0);
+            assert.strictEqual(withData.length, withInfo.size);
+            assert.strictEqual('jpeg', withInfo.format);
+            assert.strictEqual(320, withInfo.width);
+            assert.strictEqual(240, withInfo.height);
+            // Verify image is of a different size (progressive output even without mozjpeg)
+            assert.strictEqual(true, withData.length != withoutData.length);
+            done();
+          });
+      });
+  });

  if (sharp.format.magick.input.file) {
    it('Convert SVG, if supported, to PNG', function(done) {
      sharp(fixtures.inputSvg)
        .resize(100, 100)
        .toFormat('png')
-        .toFile(fixtures.path('output.svg.png'), function(err, info) {
+        .toBuffer(function(err, data, info) {
          if (err) {
            assert.strictEqual(0, err.message.indexOf('Input file is of an unsupported image format'));
+            done();
          } else {
            assert.strictEqual(true, info.size > 0);
            assert.strictEqual('png', info.format);
            assert.strictEqual(100, info.width);
            assert.strictEqual(100, info.height);
+            fixtures.assertSimilar(fixtures.expected('svg.png'), data, done);
          }
-          done();
        });
    });
  }
--- a/test/unit/jshint.js
+++ b/test/unit/jshint.js
--- a/test/unit/metadata.js
+++ b/test/unit/metadata.js
--- a/test/unit/negate.js
+++ b/test/unit/negate.js
@@ -0,0 +1,107 @@
+'use strict';
+
+var assert = require('assert');
+
+var sharp = require('../../index');
+var fixtures = require('../fixtures');
+
+sharp.cache(0);
+
+describe('Negate', function() {
+    it('negate (jpeg)', function(done) {
+        sharp(fixtures.inputJpg)
+            .resize(320, 240)
+            .negate()
+            .toBuffer(function(err, data, info) {
+                assert.strictEqual('jpeg', info.format);
+                assert.strictEqual(320, info.width);
+                assert.strictEqual(240, info.height);
+                fixtures.assertSimilar(fixtures.expected('negate.jpg'), data, done);
+            });
+    });
+
+    it('negate (png)', function(done) {
+        sharp(fixtures.inputPng)
+            .resize(320, 240)
+            .negate()
+            .toBuffer(function(err, data, info) {
+                assert.strictEqual('png', info.format);
+                assert.strictEqual(320, info.width);
+                assert.strictEqual(240, info.height);
+                fixtures.assertSimilar(fixtures.expected('negate.png'), data, done);
+            });
+    });
+
+    it('negate (png, trans)', function(done) {
+        sharp(fixtures.inputPngWithTransparency)
+            .resize(320, 240)
+            .negate()
+            .toBuffer(function(err, data, info) {
+                assert.strictEqual('png', info.format);
+                assert.strictEqual(320, info.width);
+                assert.strictEqual(240, info.height);
+                fixtures.assertSimilar(fixtures.expected('negate-trans.png'), data, done);
+            });
+    });
+
+    it('negate (png, alpha)', function(done) {
+        sharp(fixtures.inputPngWithGreyAlpha)
+            .resize(320, 240)
+            .negate()
+            .toBuffer(function(err, data, info) {
+                assert.strictEqual('png', info.format);
+                assert.strictEqual(320, info.width);
+                assert.strictEqual(240, info.height);
+                fixtures.assertSimilar(fixtures.expected('negate-alpha.png'), data, done);
+            });
+    });
+
+    if (sharp.format.webp.output.file) {
+        it('negate (webp)', function(done) {
+            sharp(fixtures.inputWebP)
+                .resize(320, 240)
+                .negate()
+                .toBuffer(function(err, data, info) {
+                    assert.strictEqual('webp', info.format);
+                    assert.strictEqual(320, info.width);
+                    assert.strictEqual(240, info.height);
+                    fixtures.assertSimilar(fixtures.expected('negate.webp'), data, done);
+                });
+        });
+
+        it('negate (webp, trans)', function(done) {
+            sharp(fixtures.inputWebPWithTransparency)
+                .resize(320, 240)
+                .negate()
+                .toBuffer(function(err, data, info) {
+                    assert.strictEqual('webp', info.format);
+                    assert.strictEqual(320, info.width);
+                    assert.strictEqual(240, info.height);
+                    fixtures.assertSimilar(fixtures.expected('negate-trans.webp'), data, done);
+                });
+        });
+    }
+
+    it('negate (true)', function(done) {
+        sharp(fixtures.inputJpg)
+            .resize(320, 240)
+            .negate(true)
+            .toBuffer(function(err, data, info) {
+                assert.strictEqual('jpeg', info.format);
+                assert.strictEqual(320, info.width);
+                assert.strictEqual(240, info.height);
+                fixtures.assertSimilar(fixtures.expected('negate.jpg'), data, done);
+            });
+    });
+
+    it('negate (false)', function(done) {
+        var output = fixtures.path('output.unmodified-by-negate.png');
+        sharp(fixtures.inputJpgWithLowContrast)
+            .negate(false)
+            .toFile(output, function(err, info) {
+                if (err) done(err);
+                fixtures.assertMaxColourDistance(output, fixtures.inputJpgWithLowContrast, 0);
+                done();
+            });
+    });
+});
--- a/test/unit/normalize.js
+++ b/test/unit/normalize.js
--- a/test/unit/overlay.js
+++ b/test/unit/overlay.js
--- a/test/unit/resize.js
+++ b/test/unit/resize.js
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Lovell Fuller	9982182926	Update perf test results ahead of v0.12.0	2015-11-23 13:09:06 +00:00
Lovell Fuller	607d157b76	Benchmark test updates ahead of v0.12.0	2015-11-23 10:53:52 +00:00
Lovell Fuller	e21277ceba	Version bump of libpng Windows dependency	2015-11-22 21:11:29 +00:00
Lovell Fuller	8012733a52	Expose libvips+deps versions attribute Add versions.json for Linux packaging Bump vips-dev Windows version for latest libpng	2015-11-22 20:58:38 +00:00
Lovell Fuller	01a1377972	Include cmath header for clang #301	2015-11-22 09:39:42 +00:00
Lovell Fuller	37e4b9b5ba	Update changelog ahead of v0.12.0 Highlight features in readme+docs Add link to Docker-based Linux CI build status	2015-11-22 09:17:51 +00:00
Lovell Fuller	8a3098604c	Remove experimental code that could prevent anti-alias filter	2015-11-21 23:37:44 +00:00
Lovell Fuller	5febce7a59	Remove executable bit from test/* file permissions	2015-11-21 23:05:48 +00:00
Lovell Fuller	3dbedf1fb6	Match g_malloc/g_free for make benefit glorious nation of Windows Remove C++ standard lib from Windows packaging	2015-11-21 22:51:32 +00:00
Lovell Fuller	0ae619dfc5	Remove stray win32 library that was causing segfaults Explicit int cast to prevent 'loss of precision' warnings Remove unnecessary semver checking from I/O tests	2015-11-21 22:18:39 +00:00
Lovell Fuller	05dd191e17	Ensure 16-bit+alpha input images work with vips_premultiply #301 Improves SVG support as *magick serves these as 16-bit Add automated tests for SVG and 16-bit+alpha PNG inputs	2015-11-21 20:21:34 +00:00
Lovell Fuller	c9ecc7a517	Document Debian 7 support Add liborc to fix openSUSE support Switch recommended *magick to ImageMagick for OS X Increase test timeouts (for Circle CI)	2015-11-19 22:47:34 +00:00
Lovell Fuller	434a433a09	Make output of packaging tests easier to understand Slight simplification of Linux packaging script	2015-11-19 21:36:16 +00:00
Lovell Fuller	3de54d897c	Merge pull request #309 from papandreou/feature/extractWithOptionsObject Add an options object to the extract operation, deprecate existing behaviour.	2015-11-18 11:48:11 +00:00
Andreas Lind	530c2a9fcf	Stop using the legacy .extract(top,left,width,height) in the documentation.	2015-11-18 12:06:10 +01:00
Andreas Lind	60b8b92630	Add support for .extract({left:...,top:...,width:...,height:...}).	2015-11-18 12:06:10 +01:00
Lovell Fuller	5842da22d8	Merge pull request #306 from dacarley/negate Add negate operation to invert all pixel values.	2015-11-17 20:45:09 +00:00
Lovell Fuller	9850e3dae0	Merge pull request #303 from dacarley/threshold Add threshold operation. Converts to greyscale then splits into black/white based on given value.	2015-11-17 20:34:40 +00:00
David Carley	3af62446fc	Implements greyscale thresholding	2015-11-17 12:15:34 -06:00
Lovell Fuller	1f71dade67	Merge pull request #307 from papandreou/wheezy Linux Dockerfile: Use Debian Wheezy as the base image	2015-11-17 17:29:35 +00:00
Lovell Fuller	8be664b66f	Merge pull request #305 from papandreou/fix/imagemagickUrl Dockerfile: Update ImageMagick tarball url (they took -5 down and up -6)	2015-11-17 17:24:30 +00:00
Andreas Lind	c0be4f1307	Dial back the required libc version to 2.13	2015-11-17 17:37:06 +01:00
Andreas Lind	d9c754f5c1	Linux Dockerfile: Use a Debian Wheezy image instead of Ubuntu Precise.	2015-11-17 17:37:06 +01:00
David Carley	33a175eafb	Implements negation.	2015-11-17 10:18:59 -06:00
Andreas Lind	7c990b3ab3	Dockerfile: Update ImageMagick tarball url (they took -5 down and up put -6).	2015-11-17 17:16:19 +01:00
Lovell Fuller	5dfeaa9fd1	Ensure gaussian blur is applied before lbb interpolator #289	2015-11-16 08:26:35 +00:00
Lovell Fuller	84fd1caa46	Switch default interpolator to bicubic #289 Only use gaussian blur for non-linear interpolators Improves performance of bilinear by ~15% Add liborc to the packaged build to improve bicubic perf Add examples of the various interpolation methods Add bilinear vs bicubic to perf tests	2015-11-15 22:04:31 +00:00
Lovell Fuller	2678d761ba	Use FreeCallback to support mixed Windows runtime libs #152	2015-11-14 13:58:05 +00:00
Lovell Fuller	ede2ee9ce3	Use Persistent wrapper to prevent GC of input Buffer #152 Avoids memcpy of input and output Buffer objects Improves Buffer and Stream performance by ~3%	2015-11-14 11:24:15 +00:00
Lovell Fuller	20f468991f	Start to use libvips 8.1.0+ features #152 Use native (un)premultiply Support normalise on Windows	2015-11-12 22:14:53 +00:00
Lovell Fuller	58d9e0fef7	Pre-extract rotate should not swap width/height #296	2015-11-11 22:34:30 +00:00
Lovell Fuller	d7278f022b	Ensure latest npm on openSUSE test	2015-11-11 22:25:17 +00:00
Lovell Fuller	7383596f8c	Allow tty-less docker-inside-docker usage	2015-11-11 21:37:04 +00:00
Lovell Fuller	f6831ab46b	Increase packaging test logging	2015-11-10 23:30:08 +00:00
Lovell Fuller	7cf0f95ed1	Fix Circle CI config CI providers should really provide config linters :)	2015-11-10 21:53:26 +00:00
Lovell Fuller	bf6b894480	Improve dependency-less documentation Start to comment ever-growing GYP config Add Circle CI config to run packaging tests	2015-11-10 21:49:45 +00:00
Lovell Fuller	ee8fcb6109	Update docs to reflect ease-of-installation	2015-11-10 00:04:06 +00:00
Lovell Fuller	05cec013fe	Ensure support for more Linux flavours Add docker-based packaging tests	2015-11-09 08:37:30 +00:00
Lovell Fuller	f4cbbd7b79	Ensure Windows CI uses x64	2015-11-07 20:22:17 +00:00
Lovell Fuller	2129adfcc3	Initial commit of local libvips binding/packaging Copy Windows DLLs into release dir as no rpath equivalent Use local libvips on Windows CI	2015-11-07 19:58:26 +00:00