Fix relative import exports

Bumps [eslint](https://github.com/eslint/eslint) from 6.8.0 to 7.0.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](https://github.com/eslint/eslint/compare/v6.8.0...v7.0.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

.eslintignore

@@ -0,0 +1,2 @@
+/browser.js
+/test/imagediff.js

.eslintrc.json

@@ -0,0 +1,19 @@
+{
+  "parserOptions": { "ecmaVersion": 2018 },
+  "extends": ["eslint:recommended", "prettier"],
+  "env": {
+    "node": true,
+    "es6": true
+  },
+  "rules": {
+    "no-var": "error"
+  },
+  "overrides": [
+    {
+      "files": ["test/*.js", "examples/*.js"],
+      "rules": {
+        "no-console": "off"
+      }
+    }
+  ]
+}

.gitignore

@@ -1 +1,6 @@
 node_modules
+.idea
+coverage
+examples/*.png
+browser\.js
+.nyc_output

.npmignore

@@ -0,0 +1,5 @@
+test
+examples
+.travis.yml
+appveyor.yml
+

.prettierignore

@@ -0,0 +1,3 @@
+/browser.js
+/test/imagediff.js
+.nyc_output

.travis.yml

@@ -0,0 +1,9 @@
+language: node_js
+after_success:
+  - if [ "$TRAVIS_NODE_VERSION" = "10" ]; then yarn coverage && yarn codecov; fi
+node_js:
+  - "10"
+  - "12"
+branches:
+  only:
+    - master

LICENSE

@@ -1,4 +1,5 @@
-Copyright (c) 2012 Kuba Niegowski
+pngjs2 original work Copyright (c) 2015 Luke Page & Original Contributors
+pngjs derived work Copyright (c) 2012 Kuba Niegowski
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -1,150 +1,411 @@
-About
+[![Build Status](https://travis-ci.com/lukeapage/pngjs.svg?branch=master)](https://travis-ci.com/lukeapage/pngjs) [![Build status](https://ci.appveyor.com/api/projects/status/qo5x8ayutr028108/branch/master?svg=true)](https://ci.appveyor.com/project/lukeapage/pngjs/branch/master) [![codecov](https://codecov.io/gh/lukeapage/pngjs/branch/master/graph/badge.svg)](https://codecov.io/gh/lukeapage/pngjs) [![npm version](https://badge.fury.io/js/pngjs.svg)](http://badge.fury.io/js/pngjs)
-========
+
-Simple PNG encoder/decoder for Node.js with no native dependencies.
+# pngjs
+
+*This is a fork of pngjs to make it work with deno*
+
+Simple PNG encoder/decoder for ~~Node.js~~ Deno with no dependencies.
+
+Based on the original [pngjs](https://github.com/niegowski/node-pngjs) with the follow enhancements.
+
+- Support for reading 1,2,4 & 16 bit files
+- Support for reading interlace files
+- Support for reading `tTRNS` transparent colours
+- Support for writing colortype 0 (grayscale), colortype 2 (RGB), colortype 4 (grayscale alpha) and colortype 6 (RGBA)
+- Sync interface as well as async
+- API compatible with pngjs and node-pngjs
+
+Known lack of support for:
+
+- Extended PNG e.g. Animation
+- Writing in colortype 3 (indexed color)
+
+# Table of Contents
+
+- [Requirements](#requirements)
+- [Comparison Table](#comparison-table)
+- [Tests](#tests)
+- [Installation](#installation)
+- [Browser](#browser)
+- [Example](#example)
+- [Async API](#async-api)
+- [Sync API](#sync-api)
+- [Changelog](#changelog)
+
+# Comparison Table
+
+| Name          | Forked From | Sync | Async | 16 Bit | 1/2/4 Bit | Interlace | Gamma  | Encodes | Tested |
+| ------------- | ----------- | ---- | ----- | ------ | --------- | --------- | ------ | ------- | ------ |
+| pngjs         |             | Yes  | Yes   | Yes    | Yes       | Yes       | Yes    | Yes     | Yes    |
+| node-png      | pngjs       | No   | Yes   | No     | No        | No        | Hidden | Yes     | Manual |
+| png-coder     | pngjs       | No   | Yes   | Yes    | No        | No        | Hidden | Yes     | Manual |
+| pngparse      |             | No   | Yes   | No     | Yes       | No        | No     | No      | Yes    |
+| pngparse-sync | pngparse    | Yes  | No    | No     | Yes       | No        | No     | No      | Yes    |
+| png-async     |             | No   | Yes   | No     | No        | No        | No     | Yes     | Yes    |
+| png-js        |             | No   | Yes   | No     | No        | No        | No     | No      | No     |
+
+Native C++ node decoders:
+
+- png
+- png-sync (sync version of above)
+- pixel-png
+- png-img
+
+# Tests
+
+Tested using [PNG Suite](http://www.schaik.com/pngsuite/). We read every file into pngjs, output it in standard 8bit colour, synchronously and asynchronously, then compare the original with the newly saved images.
+
+To run the tests, fetch the repo (tests are not distributed via npm) and install with `npm i`, run `npm test`.
+
+The only thing not converted is gamma correction - this is because multiple vendors will do gamma correction differently, so the tests will have different results on different browsers.
+
+# Installation
 
-Installation
-===============
 ```
-$ npm install node-png 
+$ npm install pngjs  --save
 ```
 
-Example
+# Browser
-==========
+
+The package has been build with a [Browserify](browserify.org) version (`npm run browserify`) and you can use the browser version by including in your code:
+
+```
+import { PNG } from 'pngjs/browser';
+```
+
+# Example
+
 ```js
-var fs = require('fs'),
+var fs = require("fs"),
-    PNG = require('pngjs').PNG;
+  PNG = require("pngjs").PNG;
 
-fs.createReadStream('in.png')
+fs.createReadStream("in.png")
-    .pipe(new PNG({
+  .pipe(
-        filterType: 4
+    new PNG({
-    }))
+      filterType: 4,
-    .on('parsed', function() {
+    })
+  )
+  .on("parsed", function () {
+    for (var y = 0; y < this.height; y++) {
+      for (var x = 0; x < this.width; x++) {
+        var idx = (this.width * y + x) << 2;
 
-        for (var y = 0; y < this.height; y++) {
+        // invert color
-            for (var x = 0; x < this.width; x++) {
+        this.data[idx] = 255 - this.data[idx];
-                var idx = (this.width * y + x) << 2;
+        this.data[idx + 1] = 255 - this.data[idx + 1];
+        this.data[idx + 2] = 255 - this.data[idx + 2];
 
-                // invert color
+        // and reduce opacity
-                this.data[idx] = 255 - this.data[idx];
+        this.data[idx + 3] = this.data[idx + 3] >> 1;
-                this.data[idx+1] = 255 - this.data[idx+1];
+      }
-                this.data[idx+2] = 255 - this.data[idx+2];
+    }
 
-                // and reduce opacity
+    this.pack().pipe(fs.createWriteStream("out.png"));
-                this.data[idx+3] = this.data[idx+3] >> 1;
+  });
-            }
-        }
-
-        this.pack().pipe(fs.createWriteStream('out.png'));
-    });
 ```
+
 For more examples see `examples` folder.
 
-Documentation
+# Async API
-================
 
 As input any color type is accepted (grayscale, rgb, palette, grayscale with alpha, rgb with alpha) but 8 bit per sample (channel) is the only supported bit depth. Interlaced mode is not supported.
 
-### Supported ancillary chunks
-- `gAMA` - gamma,
-- `tRNS` - transparency (but only for paletted image)
-
-
 ## Class: PNG
+
 `PNG` is readable and writable `Stream`.
 
-
 ### Options
+
 - `width` - use this with `height` if you want to create png from scratch
 - `height` - as above
 - `checkCRC` - whether parser should be strict about checksums in source stream (default: `true`)
-- `deflateChunkSize` - chunk size used for deflating data chunks, this should be power of 2 and must not be less than 256 and more than 32*1024 (default: 32 kB)
+- `deflateChunkSize` - chunk size used for deflating data chunks, this should be power of 2 and must not be less than 256 and more than 32\*1024 (default: 32 kB)
-- `deflateLevel` - compression level for delate (default: 9)
+- `deflateLevel` - compression level for deflate (default: 9)
-- `deflateStrategy` - compression strategy for delate (default: 3)
+- `deflateStrategy` - compression strategy for deflate (default: 3)
+- `deflateFactory` - deflate stream factory (default: `zlib.createDeflate`)
 - `filterType` - png filtering method for scanlines (default: -1 => auto, accepts array of numbers 0-4)
-
+- `colorType` - the output colorType - see constants. 0 = grayscale, no alpha, 2 = color, no alpha, 4 = grayscale & alpha, 6 = color & alpha. Default currently 6, but in the future may calculate best mode.
+- `inputColorType` - the input colorType - see constants. Default is 6 (RGBA)
+- `bitDepth` - the bitDepth of the output, 8 or 16 bits. Input data is expected to have this bit depth.
+  16 bit data is expected in the system endianness (Default: 8)
+- `inputHasAlpha` - whether the input bitmap has 4 bytes per pixel (rgb and alpha) or 3 (rgb - no alpha).
+- `bgColor` - an object containing red, green, and blue values between 0 and 255
+  that is used when packing a PNG if alpha is not to be included (default: 255,255,255)
 
 ### Event "metadata"
+
 `function(metadata) { }`
 Image's header has been parsed, metadata contains this information:
+
 - `width` image size in pixels
 - `height` image size in pixels
 - `palette` image is paletted
 - `color` image is not grayscale
 - `alpha` image contains alpha channel
-
+- `interlace` image is interlaced
 
 ### Event: "parsed"
-`function(data) { }`
-Input image has been completly parsed, `data` is complete and ready for modification.
 
+`function(data) { }`
+Input image has been completely parsed, `data` is complete and ready for modification.
 
 ### Event: "error"
+
 `function(error) { }`
 
-
 ### png.parse(data, [callback])
-Parses PNG file data. Alternatively you can stream data to instance of PNG.
+
+Parses PNG file data. Can be `String` or `Buffer`. Alternatively you can stream data to instance of PNG.
 
 Optional `callback` is once called on `error` or `parsed`. The callback gets
 two arguments `(err, data)`.
 
 Returns `this` for method chaining.
 
+#### Example
+
+```js
+new PNG({ filterType: 4 }).parse(imageData, function (error, data) {
+  console.log(error, data);
+});
+```
 
 ### png.pack()
+
 Starts converting data to PNG file Stream.
 
 Returns `this` for method chaining.
 
-
 ### png.bitblt(dst, sx, sy, w, h, dx, dy)
-Helper for image manipulation, copies rectangle of pixels from current image (`sx`, `sy`, `w`, `h`) to `dst` image (at `dx`, `dy`).
+
+Helper for image manipulation, copies a rectangle of pixels from current (i.e. the source) image (`sx`, `sy`, `w`, `h`) to `dst` image (at `dx`, `dy`).
 
 Returns `this` for method chaining.
 
+For example, the following code copies the top-left 100x50 px of `in.png` into dst and writes it to `out.png`:
+
+```js
+var dst = new PNG({ width: 100, height: 50 });
+fs.createReadStream("in.png")
+  .pipe(new PNG())
+  .on("parsed", function () {
+    this.bitblt(dst, 0, 0, 100, 50, 0, 0);
+    dst.pack().pipe(fs.createWriteStream("out.png"));
+  });
+```
+
+### Property: adjustGamma()
+
+Helper that takes data and adjusts it to be gamma corrected. Note that it is not 100% reliable with transparent colours because that requires knowing the background colour the bitmap is rendered on to.
+
+In tests against PNG suite it compared 100% with chrome on all 8 bit and below images. On IE there were some differences.
+
+The following example reads a file, adjusts the gamma (which sets the gamma to 0) and writes it out again, effectively removing any gamma correction from the image.
+
+```js
+fs.createReadStream("in.png")
+  .pipe(new PNG())
+  .on("parsed", function () {
+    this.adjustGamma();
+    this.pack().pipe(fs.createWriteStream("out.png"));
+  });
+```
 
 ### Property: width
+
 Width of image in pixels
 
-
 ### Property: height
+
 Height of image in pixels
 
-
 ### Property: data
+
 Buffer of image pixel data. Every pixel consists 4 bytes: R, G, B, A (opacity).
 
-
 ### Property: gamma
+
 Gamma of image (0 if not specified)
 
-Changelog
+## Packing a PNG and removing alpha (RGBA to RGB)
-============
 
-### 0.4.0 - Jun 05 2013
+When removing the alpha channel from an image, there needs to be a background color to correctly
-  - fixed reading of destroyed input stream
+convert each pixel's transparency to the appropriate RGB value. By default, pngjs will flatten
+the image against a white background. You can override this in the options:
 
-### 0.4.0-alpha - 29 Nov 2012
+```js
-  - added zlib deflateStrategy option, default to Z_RLE (by pdpotter)
+var fs = require("fs"),
-  - added possibility to use multiple filters (by pdpotter, modified by niegowski)
+  PNG = require("pngjs").PNG;
 
-### 0.3.0-alpha - 23 Aug 2012
+fs.createReadStream("in.png")
-  - Processing data as Streams, not complete Buffers of data
+  .pipe(
+    new PNG({
+      colorType: 2,
+      bgColor: {
+        red: 0,
+        green: 255,
+        blue: 0,
+      },
+    })
+  )
+  .on("parsed", function () {
+    this.pack().pipe(fs.createWriteStream("out.png"));
+  });
+```
 
-### 0.2.0-alpha - 21 Aug 2012
+# Sync API
-  - Input added palette, grayscale, no alpha support
-  - Better scanline filter selection
 
-### 0.1.0-alpha - 19 Aug 2012
+## PNG.sync
-  - First version
 
-License
+### PNG.sync.read(buffer)
-=========
+
+Take a buffer and returns a PNG image. The properties on the image include the meta data and `data` as per the async API above.
+
+```
+var data = fs.readFileSync('in.png');
+var png = PNG.sync.read(data);
+```
+
+### PNG.sync.write(png)
+
+Take a PNG image and returns a buffer. The properties on the image include the meta data and `data` as per the async API above.
+
+```
+var data = fs.readFileSync('in.png');
+var png = PNG.sync.read(data);
+var options = { colorType: 6 };
+var buffer = PNG.sync.write(png, options);
+fs.writeFileSync('out.png', buffer);
+```
+
+### PNG.adjustGamma(src)
+
+Adjusts the gamma of a sync image. See the async adjustGamma.
+
+```
+var data = fs.readFileSync('in.png');
+var png = PNG.sync.read(data);
+PNG.adjustGamma(png);
+```
+
+# Changelog
+
+### 5.0.0 - 15/04/2020
+
+- Drop support for Node 8
+- Browserified bundle may now contain ES20(15-20) code if the supported node version supports it. Please run the browserified version through babel if you need to support older browsers.
+
+### 4.0.1 - 15/04/2020
+
+- Fix to possible null reference in nextTick of async method
+
+### 4.0.0 - 09/04/2020
+
+- Fix issue in newer nodes with using Buffer
+- Fix async issue with some png files
+- Drop support for Node 4 & 6
+
+### 3.4.0 - 09/03/2019
+
+- Include whether the png has alpha in the meta data
+- emit an error if the image is truncated instead of hanging
+- Add a browserified version
+- speed up some mapping functions
+
+### 3.3.3 - 19/04/2018
+
+- Real fix for node 9
+
+### 3.3.2 - 16/02/2018
+
+- Fix for node 9
+
+### 3.3.1 - 15/11/2017
+
+- Bugfixes and removal of es6
+
+### 3.3.0
+
+- Add writing 16 bit channels and support for grayscale input
+
+### 3.2.0 - 30/04/2017
+
+- Support for encoding 8-bit grayscale images
+
+### 3.1.0 - 30/04/2017
+
+- Support for pngs with zlib chunks that are malformed after valid data
+
+### 3.0.1 - 16/02/2017
+
+- Fix single pixel pngs
+
+### 3.0.0 - 03/08/2016
+
+- Drop support for node below v4 and iojs. Pin to 2.3.0 to use with old, unsupported or patched node versions.
+
+### 2.3.0 - 22/04/2016
+
+- Support for sync in node 0.10
+
+### 2.2.0 - 04/12/2015
+
+- Add sync write api
+- Fix newfile example
+- Correct comparison table
+
+### 2.1.0 - 28/10/2015
+
+- rename package to pngjs
+- added 'bgColor' option
+
+### 2.0.0 - 08/10/2015
+
+- fixes to readme
+- _breaking change_ - bitblt on the png prototype now doesn't take a unused, unnecessary src first argument
+
+### 1.2.0 - 13/09/2015
+
+- support passing colorType to write PNG's and writing bitmaps without alpha information
+
+### 1.1.0 - 07/09/2015
+
+- support passing a deflate factory for controlled compression
+
+### 1.0.2 - 22/08/2015
+
+- Expose all PNG creation info
+
+### 1.0.1 - 21/08/2015
+
+- Fix non square interlaced files
+
+### 1.0.0 - 08/08/2015
+
+- More tests
+- source linted
+- maintainability refactorings
+- async API - exceptions in reading now emit warnings
+- documentation improvement - sync api now documented, adjustGamma documented
+- breaking change - gamma chunk is now written. previously a read then write would destroy gamma information, now it is persisted.
+
+### 0.0.3 - 03/08/2015
+
+- Error handling fixes
+- ignore files for smaller npm footprint
+
+### 0.0.2 - 02/08/2015
+
+- Bugfixes to interlacing, support for transparent colours
+
+### 0.0.1 - 02/08/2015
+
+- Initial release, see pngjs for older changelog.
+
+# License
 
 (The MIT License)
 
-Copyright (c) 2012 Kuba Niegowski
-
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights

appveyor.yml

@@ -0,0 +1,28 @@
+version: "{build}"
+
+clone_depth: 10
+
+environment:
+  matrix:
+    - nodejs_version: "10"
+    - nodejs_version: "12"
+
+install:
+  - ps: Install-Product node $env:nodejs_version
+  - npm install
+
+build: off
+
+test_script:
+  - node --version && npm --version
+  - npm test
+
+cache:
+  - node_modules # local npm modules
+
+matrix:
+  fast_finish: true
+
+branches:
+  only:
+    - master

examples/16bit_write.js

@@ -0,0 +1,50 @@
+#!/usr/bin/env node
+
+let fs = require("fs");
+let PNG = require("../lib/png").PNG;
+let w = 32;
+let h = 64;
+
+/// RGBA input (color type 6)
+let buffer = Buffer.alloc(2 * w * h * 4);
+let bitmap = new Uint16Array(buffer.buffer);
+for (let i = 0; i < h; i++) {
+  for (let j = 0; j < w; j++) {
+    bitmap[i * 4 * w + 4 * j] = (i * 65535) / h;
+    bitmap[i * 4 * w + 4 * j + 1] = (j * 65535) / w;
+    bitmap[i * 4 * w + 4 * j + 2] = ((h - i) * 65535) / h;
+    bitmap[i * 4 * w + 4 * j + 3] = 65535;
+  }
+}
+
+let png = new PNG({
+  width: w,
+  height: h,
+  bitDepth: 16,
+  colorType: 6,
+  inputColorType: 6,
+  inputHasAlpha: true,
+});
+
+png.data = buffer;
+png.pack().pipe(fs.createWriteStream("colortype6.png"));
+
+//////// Grayscale 16 bits///////
+
+buffer = Buffer.alloc(2 * w * h);
+bitmap = new Uint16Array(buffer.buffer);
+for (let i = 0; i < h; i++) {
+  for (let j = 0; j < w; j++) bitmap[i * w + j] = (i * 65535) / h;
+}
+
+png = new PNG({
+  width: w,
+  height: h,
+  bitDepth: 16,
+  colorType: 0,
+  inputColorType: 0,
+  inputHasAlpha: false,
+});
+
+png.data = buffer;
+png.pack().pipe(fs.createWriteStream("colortype0.png"));

examples/fromdocs.js

@@ -1,26 +1,22 @@
+let fs = require("fs"),
+  PNG = require("../lib/png").PNG; // note require('pngjs') outside this project
 
-var fs = require('fs'),
+fs.createReadStream("test/in/basi0g01.png")
-    PNG = require('pngjs').PNG;
+  .pipe(new PNG({}))
+  .on("parsed", function () {
+    for (let y = 0; y < this.height; y++) {
+      for (let x = 0; x < this.width; x++) {
+        let idx = (this.width * y + x) << 2;
 
-fs.createReadStream('in.png')
+        // invert color
-    .pipe(new PNG({
+        this.data[idx] = 255 - this.data[idx];
-        filterType: 4
+        this.data[idx + 1] = 255 - this.data[idx + 1];
-    }))
+        this.data[idx + 2] = 255 - this.data[idx + 2];
-    .on('parsed', function() {
 
-        for (var y = 0; y < this.height; y++) {
+        // and reduce opacity
-            for (var x = 0; x < this.width; x++) {
+        this.data[idx + 3] = this.data[idx + 3] >> 1;
-                var idx = (this.width * y + x) << 2;
+      }
+    }
 
-                // invert color
+    this.pack().pipe(fs.createWriteStream("out.png"));
-                this.data[idx] = 255 - this.data[idx];
+  });
-                this.data[idx+1] = 255 - this.data[idx+1];
-                this.data[idx+2] = 255 - this.data[idx+2];
-
-                // and reduce opacity
-                this.data[idx+3] = this.data[idx+3] >> 1;
-            }
-        }
-
-        this.pack().pipe(fs.createWriteStream('out.png'));
-    });

examples/newfile.js

@@ -0,0 +1,25 @@
+let PNG = require("../lib/png").PNG;
+let fs = require("fs");
+
+let newfile = new PNG({ width: 10, height: 10 });
+
+for (let y = 0; y < newfile.height; y++) {
+  for (let x = 0; x < newfile.width; x++) {
+    let idx = (newfile.width * y + x) << 2;
+
+    let col =
+      (x < newfile.width >> 1) ^ (y < newfile.height >> 1) ? 0xe5 : 0xff;
+
+    newfile.data[idx] = col;
+    newfile.data[idx + 1] = col;
+    newfile.data[idx + 2] = col;
+    newfile.data[idx + 3] = 0xff;
+  }
+}
+
+newfile
+  .pack()
+  .pipe(fs.createWriteStream(__dirname + "/newfile.png"))
+  .on("finish", function () {
+    console.log("Written!");
+  });

examples/set-colortype.js

@@ -0,0 +1,34 @@
+let fs = require("fs");
+let PNG = require("../lib/png").PNG;
+let w = 320;
+let h = 200;
+
+let bitmapWithoutAlpha = Buffer.alloc(w * h * 3);
+let ofs = 0;
+for (let i = 0; i < bitmapWithoutAlpha.length; i += 3) {
+  bitmapWithoutAlpha[ofs++] = 0xff;
+  bitmapWithoutAlpha[ofs++] = i % 0xff;
+  bitmapWithoutAlpha[ofs++] = (i / 3) % 0xff;
+}
+
+let png = new PNG({
+  width: w,
+  height: h,
+  bitDepth: 8,
+  colorType: 2,
+  inputHasAlpha: false,
+});
+
+png.data = bitmapWithoutAlpha;
+png.pack().pipe(fs.createWriteStream("colortype2.png"));
+
+png = new PNG({
+  width: w,
+  height: h,
+  bitDepth: 8,
+  colorType: 6,
+  inputHasAlpha: false,
+});
+
+png.data = bitmapWithoutAlpha;
+png.pack().pipe(fs.createWriteStream("colortype6.png"));

examples/simple.js

@@ -1,30 +1,28 @@
 #!/usr/bin/env node
 
-var fs = require('fs'),
+let fs = require("fs"),
-    PNG = require('../lib/png').PNG;
+  PNG = require("../lib/png").PNG;
 
+let png = new PNG({
+    filterType: -1,
+  }),
+  src = fs.createReadStream(process.argv[2]),
+  dst = fs.createWriteStream(process.argv[3] || "out.png");
 
-var png = new PNG({
+png.on("parsed", function () {
-        filterType: -1
+  for (let y = 0; y < png.height; y++) {
-    }),
+    for (let x = 0; x < png.width; x++) {
-    src = fs.createReadStream(process.argv[2]),
+      let idx = (png.width * y + x) << 2;
-    dst = fs.createWriteStream(process.argv[3] || 'out.png');
 
-
+      if (
-png.on('parsed', function() {
+        Math.abs(png.data[idx] - png.data[idx + 1]) <= 1 &&
-
+        Math.abs(png.data[idx + 1] - png.data[idx + 2]) <= 1
-    for (var y = 0; y < png.height; y++) {
+      )
-        for (var x = 0; x < png.width; x++) {
+        png.data[idx] = png.data[idx + 1] = png.data[idx + 2];
-            var idx = (png.width * y + x) << 2;
-
-            if (Math.abs(png.data[idx] - png.data[idx+1]) <= 1
-                    && Math.abs(png.data[idx+1] - png.data[idx+2]) <= 1)
-                png.data[idx] = png.data[idx+1] = png.data[idx+2];
-
-        }
     }
+  }
 
-    png.pack().pipe(dst);
+  png.pack().pipe(dst);
 });
 
 src.pipe(png);

examples/sync.js

@@ -0,0 +1,18 @@
+#!/usr/bin/env node
+
+let fs = require("fs"),
+  PNG = require("../lib/png").PNG;
+
+let srcFname = process.argv[2],
+  dstFname = process.argv[3] || "out.png";
+
+// Read a PNG file
+let data = fs.readFileSync(srcFname);
+// Parse it
+let png = PNG.sync.read(data, {
+  filterType: -1,
+});
+// Pack it back into a PNG data
+let buff = PNG.sync.write(png);
+// Write a PNG file
+fs.writeFileSync(dstFname, buff);

examples/test/bg.js

@@ -1,27 +0,0 @@
-#!/usr/bin/env node
-
-var fs = require('fs'),
-    PNG = require('pngjs').PNG;
-
-
-var png = new PNG({
-    width: 10,
-    height: 10,
-    filterType: -1
-});
-
-
-for (var y = 0; y < png.height; y++) {
-    for (var x = 0; x < png.width; x++) {
-        var idx = (png.width * y + x) << 2;
-
-        var col = x < (png.width >> 1) ^ y < (png.height >> 1) ? 0xe5 : 0xff;
-
-        png.data[idx  ] = col;
-        png.data[idx+1] = col;
-        png.data[idx+2] = col;
-        png.data[idx+3] = 0xff;
-    }
-}
-
-png.pack().pipe(fs.createWriteStream(__dirname + '/bg.png'));

examples/test/list.html

@@ -1,38 +0,0 @@
-<!DOCTYPE html>
-<html>
-<head>
-    <title>PNG Test</title>
-    <style>
-        body { background: #eee; font: 12px Arial; margin: 10px; }
-        img { margin: 2px; background: url(bg.png); }
-        h3 { margin: 10px 0; }
-    </style>
-</head>
-<body>
-    <h3>Basic</h3>
-    <img src="img/basn0g08.png"> <img src="out/basn0g08.png"> grayscale<br>
-    <img src="img/basn2c08.png"> <img src="out/basn2c08.png"> color<br>
-    <img src="img/basn3p08.png"> <img src="out/basn3p08.png"> paletted<br>
-    <img src="img/basn4a08.png"> <img src="out/basn4a08.png"> grayscale + alpha<br>
-    <img src="img/basn6a08.png"> <img src="out/basn6a08.png"> color + alpha<br>
-
-    <h3>Image filtering</h3>
-    <img src="img/f00n0g08.png"> <img src="out/f00n0g08.png"> grayscale, filter 0<br>
-    <img src="img/f00n2c08.png"> <img src="out/f00n2c08.png"> color, filter 0<br>
-    <img src="img/f01n0g08.png"> <img src="out/f01n0g08.png"> grayscale, filter 1<br>
-    <img src="img/f01n2c08.png"> <img src="out/f01n2c08.png"> color, filter 1<br>
-    <img src="img/f02n0g08.png"> <img src="out/f02n0g08.png"> grayscale, filter 2<br>
-    <img src="img/f02n2c08.png"> <img src="out/f02n2c08.png"> color, filter 2<br>
-    <img src="img/f03n0g08.png"> <img src="out/f03n0g08.png"> grayscale, filter 3<br>
-    <img src="img/f03n2c08.png"> <img src="out/f03n2c08.png"> color, filter 3<br>
-    <img src="img/f04n0g08.png"> <img src="out/f04n0g08.png"> grayscale, filter 4<br>
-    <img src="img/f04n2c08.png"> <img src="out/f04n2c08.png"> color, filter 4<br>
-
-    <h3>Transparency</h3>
-    <img src="img/tp0n0g08.png"> <img src="out/tp0n0g08.png"> grayscale, not transparent<br>
-    <img src="img/tp0n2c08.png"> <img src="out/tp0n2c08.png"> color, not transparent<br>
-    <img src="img/tp0n3p08.png"> <img src="out/tp0n3p08.png"> paletted, not transparent<br>
-    <img src="img/tbrn2c08.png"> <img src="out/tbrn2c08.png"> color, transparent<br>
-    <img src="img/tp1n3p08.png"> <img src="out/tp1n3p08.png"> paletted, transparent<br>
-</body>
-</html>

examples/test/test.js

@@ -1,38 +0,0 @@
-
-var fs = require('fs'),
-    PNG = require('pngjs').PNG;
-
-
-fs.readdir(__dirname + '/img/', function(err, files) {
-    if (err) throw err;
-
-    files.forEach(function(file) {
-
-        if (!file.match(/\.png$/i))
-            return;
-
-        fs.createReadStream(__dirname + '/img/' + file)
-            .pipe(new PNG())
-            .on('parsed', function() {
-
-                if (this.gamma) {
-                    for (var y = 0; y < this.height; y++) {
-                        for (var x = 0; x < this.width; x++) {
-                            var idx = (this.width * y + x) << 2;
-
-                            for (var i = 0; i < 3; i++) {
-                                var sample = this.data[idx + i] / 255;
-                                sample = Math.pow(sample, 1 / 2.2 / this.gamma);
-                                this.data[idx + i] = Math.round(sample * 255);
-                            }
-                        }
-                    }
-                }
-
-                this.pack()
-                    .pipe(fs.createWriteStream(__dirname + '/out/' + file));
-
-            });
-
-    });
-});

lib/bitmapper.js

@@ -0,0 +1,265 @@
+import interlaceUtils from "./interlace.js";
+
+let pixelBppMapper = [
+  // 0 - dummy entry
+  function () {},
+
+  // 1 - L
+  // 0: 0, 1: 0, 2: 0, 3: 0xff
+  function (pxData, data, pxPos, rawPos) {
+    if (rawPos === data.length) {
+      throw new Error("Ran out of data");
+    }
+
+    let pixel = data[rawPos];
+    pxData[pxPos] = pixel;
+    pxData[pxPos + 1] = pixel;
+    pxData[pxPos + 2] = pixel;
+    pxData[pxPos + 3] = 0xff;
+  },
+
+  // 2 - LA
+  // 0: 0, 1: 0, 2: 0, 3: 1
+  function (pxData, data, pxPos, rawPos) {
+    if (rawPos + 1 >= data.length) {
+      throw new Error("Ran out of data");
+    }
+
+    let pixel = data[rawPos];
+    pxData[pxPos] = pixel;
+    pxData[pxPos + 1] = pixel;
+    pxData[pxPos + 2] = pixel;
+    pxData[pxPos + 3] = data[rawPos + 1];
+  },
+
+  // 3 - RGB
+  // 0: 0, 1: 1, 2: 2, 3: 0xff
+  function (pxData, data, pxPos, rawPos) {
+    if (rawPos + 2 >= data.length) {
+      throw new Error("Ran out of data");
+    }
+
+    pxData[pxPos] = data[rawPos];
+    pxData[pxPos + 1] = data[rawPos + 1];
+    pxData[pxPos + 2] = data[rawPos + 2];
+    pxData[pxPos + 3] = 0xff;
+  },
+
+  // 4 - RGBA
+  // 0: 0, 1: 1, 2: 2, 3: 3
+  function (pxData, data, pxPos, rawPos) {
+    if (rawPos + 3 >= data.length) {
+      throw new Error("Ran out of data");
+    }
+
+    pxData[pxPos] = data[rawPos];
+    pxData[pxPos + 1] = data[rawPos + 1];
+    pxData[pxPos + 2] = data[rawPos + 2];
+    pxData[pxPos + 3] = data[rawPos + 3];
+  },
+];
+
+let pixelBppCustomMapper = [
+  // 0 - dummy entry
+  function () {},
+
+  // 1 - L
+  // 0: 0, 1: 0, 2: 0, 3: 0xff
+  function (pxData, pixelData, pxPos, maxBit) {
+    let pixel = pixelData[0];
+    pxData[pxPos] = pixel;
+    pxData[pxPos + 1] = pixel;
+    pxData[pxPos + 2] = pixel;
+    pxData[pxPos + 3] = maxBit;
+  },
+
+  // 2 - LA
+  // 0: 0, 1: 0, 2: 0, 3: 1
+  function (pxData, pixelData, pxPos) {
+    let pixel = pixelData[0];
+    pxData[pxPos] = pixel;
+    pxData[pxPos + 1] = pixel;
+    pxData[pxPos + 2] = pixel;
+    pxData[pxPos + 3] = pixelData[1];
+  },
+
+  // 3 - RGB
+  // 0: 0, 1: 1, 2: 2, 3: 0xff
+  function (pxData, pixelData, pxPos, maxBit) {
+    pxData[pxPos] = pixelData[0];
+    pxData[pxPos + 1] = pixelData[1];
+    pxData[pxPos + 2] = pixelData[2];
+    pxData[pxPos + 3] = maxBit;
+  },
+
+  // 4 - RGBA
+  // 0: 0, 1: 1, 2: 2, 3: 3
+  function (pxData, pixelData, pxPos) {
+    pxData[pxPos] = pixelData[0];
+    pxData[pxPos + 1] = pixelData[1];
+    pxData[pxPos + 2] = pixelData[2];
+    pxData[pxPos + 3] = pixelData[3];
+  },
+];
+
+function bitRetriever(data, depth) {
+  let leftOver = [];
+  let i = 0;
+
+  function split() {
+    if (i === data.length) {
+      throw new Error("Ran out of data");
+    }
+    let byte = data[i];
+    i++;
+    let byte8, byte7, byte6, byte5, byte4, byte3, byte2, byte1;
+    switch (depth) {
+      default:
+        throw new Error("unrecognised depth");
+      case 16:
+        byte2 = data[i];
+        i++;
+        leftOver.push((byte << 8) + byte2);
+        break;
+      case 4:
+        byte2 = byte & 0x0f;
+        byte1 = byte >> 4;
+        leftOver.push(byte1, byte2);
+        break;
+      case 2:
+        byte4 = byte & 3;
+        byte3 = (byte >> 2) & 3;
+        byte2 = (byte >> 4) & 3;
+        byte1 = (byte >> 6) & 3;
+        leftOver.push(byte1, byte2, byte3, byte4);
+        break;
+      case 1:
+        byte8 = byte & 1;
+        byte7 = (byte >> 1) & 1;
+        byte6 = (byte >> 2) & 1;
+        byte5 = (byte >> 3) & 1;
+        byte4 = (byte >> 4) & 1;
+        byte3 = (byte >> 5) & 1;
+        byte2 = (byte >> 6) & 1;
+        byte1 = (byte >> 7) & 1;
+        leftOver.push(byte1, byte2, byte3, byte4, byte5, byte6, byte7, byte8);
+        break;
+    }
+  }
+
+  return {
+    get: function (count) {
+      while (leftOver.length < count) {
+        split();
+      }
+      let returner = leftOver.slice(0, count);
+      leftOver = leftOver.slice(count);
+      return returner;
+    },
+    resetAfterLine: function () {
+      leftOver.length = 0;
+    },
+    end: function () {
+      if (i !== data.length) {
+        throw new Error("extra data found");
+      }
+    },
+  };
+}
+
+function mapImage8Bit(image, pxData, getPxPos, bpp, data, rawPos) {
+  // eslint-disable-line max-params
+  let imageWidth = image.width;
+  let imageHeight = image.height;
+  let imagePass = image.index;
+  for (let y = 0; y < imageHeight; y++) {
+    for (let x = 0; x < imageWidth; x++) {
+      let pxPos = getPxPos(x, y, imagePass);
+      pixelBppMapper[bpp](pxData, data, pxPos, rawPos);
+      rawPos += bpp; //eslint-disable-line no-param-reassign
+    }
+  }
+  return rawPos;
+}
+
+function mapImageCustomBit(image, pxData, getPxPos, bpp, bits, maxBit) {
+  // eslint-disable-line max-params
+  let imageWidth = image.width;
+  let imageHeight = image.height;
+  let imagePass = image.index;
+  for (let y = 0; y < imageHeight; y++) {
+    for (let x = 0; x < imageWidth; x++) {
+      let pixelData = bits.get(bpp);
+      let pxPos = getPxPos(x, y, imagePass);
+      pixelBppCustomMapper[bpp](pxData, pixelData, pxPos, maxBit);
+    }
+    bits.resetAfterLine();
+  }
+}
+
+export default function (data, bitmapInfo) {
+  let width = bitmapInfo.width;
+  let height = bitmapInfo.height;
+  let depth = bitmapInfo.depth;
+  let bpp = bitmapInfo.bpp;
+  let interlace = bitmapInfo.interlace;
+  let bits;
+
+  if (depth !== 8) {
+    bits = bitRetriever(data, depth);
+  }
+  let pxData;
+  if (depth <= 8) {
+    pxData = Buffer.alloc(width * height * 4);
+  } else {
+    pxData = new Uint16Array(width * height * 4);
+  }
+  let maxBit = Math.pow(2, depth) - 1;
+  let rawPos = 0;
+  let images;
+  let getPxPos;
+
+  if (interlace) {
+    images = interlaceUtils.getImagePasses(width, height);
+    getPxPos = interlaceUtils.getInterlaceIterator(width, height);
+  } else {
+    let nonInterlacedPxPos = 0;
+    getPxPos = function () {
+      let returner = nonInterlacedPxPos;
+      nonInterlacedPxPos += 4;
+      return returner;
+    };
+    images = [{ width: width, height: height }];
+  }
+
+  for (let imageIndex = 0; imageIndex < images.length; imageIndex++) {
+    if (depth === 8) {
+      rawPos = mapImage8Bit(
+        images[imageIndex],
+        pxData,
+        getPxPos,
+        bpp,
+        data,
+        rawPos
+      );
+    } else {
+      mapImageCustomBit(
+        images[imageIndex],
+        pxData,
+        getPxPos,
+        bpp,
+        bits,
+        maxBit
+      );
+    }
+  }
+  if (depth === 8) {
+    if (rawPos !== data.length) {
+      throw new Error("extra data found");
+    }
+  } else {
+    bits.end();
+  }
+
+  return pxData;
+};

lib/bitpacker.js

@@ -0,0 +1,156 @@
+import constants from "./constants.js";
+
+export default function (dataIn, width, height, options) {
+  let outHasAlpha =
+    [constants.COLORTYPE_COLOR_ALPHA, constants.COLORTYPE_ALPHA].indexOf(
+      options.colorType
+    ) !== -1;
+  if (options.colorType === options.inputColorType) {
+    let bigEndian = (function () {
+      let buffer = new ArrayBuffer(2);
+      new DataView(buffer).setInt16(0, 256, true /* littleEndian */);
+      // Int16Array uses the platform's endianness.
+      return new Int16Array(buffer)[0] !== 256;
+    })();
+    // If no need to convert to grayscale and alpha is present/absent in both, take a fast route
+    if (options.bitDepth === 8 || (options.bitDepth === 16 && bigEndian)) {
+      return dataIn;
+    }
+  }
+
+  // map to a UInt16 array if data is 16bit, fix endianness below
+  let data = options.bitDepth !== 16 ? dataIn : new Uint16Array(dataIn.buffer);
+
+  let maxValue = 255;
+  let inBpp = constants.COLORTYPE_TO_BPP_MAP[options.inputColorType];
+  if (inBpp === 4 && !options.inputHasAlpha) {
+    inBpp = 3;
+  }
+  let outBpp = constants.COLORTYPE_TO_BPP_MAP[options.colorType];
+  if (options.bitDepth === 16) {
+    maxValue = 65535;
+    outBpp *= 2;
+  }
+  let outData = Buffer.alloc(width * height * outBpp);
+
+  let inIndex = 0;
+  let outIndex = 0;
+
+  let bgColor = options.bgColor || {};
+  if (bgColor.red === undefined) {
+    bgColor.red = maxValue;
+  }
+  if (bgColor.green === undefined) {
+    bgColor.green = maxValue;
+  }
+  if (bgColor.blue === undefined) {
+    bgColor.blue = maxValue;
+  }
+
+  function getRGBA() {
+    let red;
+    let green;
+    let blue;
+    let alpha = maxValue;
+    switch (options.inputColorType) {
+      case constants.COLORTYPE_COLOR_ALPHA:
+        alpha = data[inIndex + 3];
+        red = data[inIndex];
+        green = data[inIndex + 1];
+        blue = data[inIndex + 2];
+        break;
+      case constants.COLORTYPE_COLOR:
+        red = data[inIndex];
+        green = data[inIndex + 1];
+        blue = data[inIndex + 2];
+        break;
+      case constants.COLORTYPE_ALPHA:
+        alpha = data[inIndex + 1];
+        red = data[inIndex];
+        green = red;
+        blue = red;
+        break;
+      case constants.COLORTYPE_GRAYSCALE:
+        red = data[inIndex];
+        green = red;
+        blue = red;
+        break;
+      default:
+        throw new Error(
+          "input color type:" +
+            options.inputColorType +
+            " is not supported at present"
+        );
+    }
+
+    if (options.inputHasAlpha) {
+      if (!outHasAlpha) {
+        alpha /= maxValue;
+        red = Math.min(
+          Math.max(Math.round((1 - alpha) * bgColor.red + alpha * red), 0),
+          maxValue
+        );
+        green = Math.min(
+          Math.max(Math.round((1 - alpha) * bgColor.green + alpha * green), 0),
+          maxValue
+        );
+        blue = Math.min(
+          Math.max(Math.round((1 - alpha) * bgColor.blue + alpha * blue), 0),
+          maxValue
+        );
+      }
+    }
+    return { red: red, green: green, blue: blue, alpha: alpha };
+  }
+
+  for (let y = 0; y < height; y++) {
+    for (let x = 0; x < width; x++) {
+      let rgba = getRGBA(data, inIndex);
+
+      switch (options.colorType) {
+        case constants.COLORTYPE_COLOR_ALPHA:
+        case constants.COLORTYPE_COLOR:
+          if (options.bitDepth === 8) {
+            outData[outIndex] = rgba.red;
+            outData[outIndex + 1] = rgba.green;
+            outData[outIndex + 2] = rgba.blue;
+            if (outHasAlpha) {
+              outData[outIndex + 3] = rgba.alpha;
+            }
+          } else {
+            outData.writeUInt16BE(rgba.red, outIndex);
+            outData.writeUInt16BE(rgba.green, outIndex + 2);
+            outData.writeUInt16BE(rgba.blue, outIndex + 4);
+            if (outHasAlpha) {
+              outData.writeUInt16BE(rgba.alpha, outIndex + 6);
+            }
+          }
+          break;
+        case constants.COLORTYPE_ALPHA:
+        case constants.COLORTYPE_GRAYSCALE: {
+          // Convert to grayscale and alpha
+          let grayscale = (rgba.red + rgba.green + rgba.blue) / 3;
+          if (options.bitDepth === 8) {
+            outData[outIndex] = grayscale;
+            if (outHasAlpha) {
+              outData[outIndex + 1] = rgba.alpha;
+            }
+          } else {
+            outData.writeUInt16BE(grayscale, outIndex);
+            if (outHasAlpha) {
+              outData.writeUInt16BE(rgba.alpha, outIndex + 2);
+            }
+          }
+          break;
+        }
+        default:
+          throw new Error("unrecognised color Type " + options.colorType);
+      }
+
+      inIndex += inBpp;
+      outIndex += outBpp;
+    }
+  }
+
+  return outData;
+};

lib/chunkstream.js

@@ -1,200 +1,190 @@
-// Copyright (c) 2012 Kuba Niegowski
+let util = require("util");
-//
+let Stream = require("stream");
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
 
-'use strict';
+let ChunkStream = function () {
+  Stream.call(this);
 
+  this._buffers = [];
+  this._buffered = 0;
 
-var util = require('util'),
+  this._reads = [];
-    Stream = require('stream');
+  this._paused = false;
 
-
+  this._encoding = "utf8";
-var ChunkStream = module.exports = function() {
+  this.writable = true;
-    Stream.call(this);
-
-    this._buffers = [];
-    this._buffered = 0;
-
-    this._reads = [];
-    this._paused = false;
-
-    this._encoding = 'utf8';
-    this.writable = true;
 };
+
+export default ChunkStream;
+
 util.inherits(ChunkStream, Stream);
 
+ChunkStream.prototype.read = function (length, callback) {
+  this._reads.push({
+    length: Math.abs(length), // if length < 0 then at most this length
+    allowLess: length < 0,
+    func: callback,
+  });
 
-ChunkStream.prototype.read = function(length, callback) {
+  process.nextTick(
-
+    function () {
-    this._reads.push({
-        length: Math.abs(length),  // if length < 0 then at most this length
-        allowLess: length < 0,
-        func: callback
-    });
-
-    process.nextTick(function() {
       this._process();
 
       // its paused and there is not enought data then ask for more
-      if (this._paused && this._reads.length > 0) {
+      if (this._paused && this._reads && this._reads.length > 0) {
-          this._paused = false;
+        this._paused = false;
 
-          this.emit('drain');
+        this.emit("drain");
       }
-    }.bind(this));
+    }.bind(this)
+  );
 };
 
-ChunkStream.prototype.write = function(data, encoding) {
+ChunkStream.prototype.write = function (data, encoding) {
+  if (!this.writable) {
+    this.emit("error", new Error("Stream not writable"));
+    return false;
+  }
 
-    if (!this.writable) {
+  let dataBuffer;
-        this.emit('error', new Error('Stream not writable'));
+  if (Buffer.isBuffer(data)) {
-        return false;
+    dataBuffer = data;
-    }
+  } else {
+    dataBuffer = Buffer.from(data, encoding || this._encoding);
+  }
 
-    if (!Buffer.isBuffer(data))
+  this._buffers.push(dataBuffer);
-        data = new Buffer(data, encoding || this._encoding);
+  this._buffered += dataBuffer.length;
 
-    this._buffers.push(data);
+  this._process();
-    this._buffered += data.length;
 
+  // ok if there are no more read requests
+  if (this._reads && this._reads.length === 0) {
+    this._paused = true;
+  }
+
+  return this.writable && !this._paused;
+};
+
+ChunkStream.prototype.end = function (data, encoding) {
+  if (data) {
+    this.write(data, encoding);
+  }
+
+  this.writable = false;
+
+  // already destroyed
+  if (!this._buffers) {
+    return;
+  }
+
+  // enqueue or handle end
+  if (this._buffers.length === 0) {
+    this._end();
+  } else {
+    this._buffers.push(null);
     this._process();
-
+  }
-    // ok if there are no more read requests
-    if (this._reads && this._reads.length == 0)
-        this._paused = true;
-
-    return this.writable && !this._paused;
-};
-
-ChunkStream.prototype.end = function(data, encoding) {
-
-    if (data) this.write(data, encoding);
-
-    this.writable = false;
-
-    // already destroyed
-    if (!this._buffers) return;
-
-    // enqueue or handle end
-    if (this._buffers.length == 0) {
-        this._end();
-    } else {
-        this._buffers.push(null);
-        this._process();
-    }
 };
 
 ChunkStream.prototype.destroySoon = ChunkStream.prototype.end;
 
-ChunkStream.prototype._end = function() {
+ChunkStream.prototype._end = function () {
+  if (this._reads.length > 0) {
+    this.emit("error", new Error("Unexpected end of input"));
+  }
 
-    if (this._reads.length > 0) {
+  this.destroy();
-        this.emit('error',
+};
-            new Error('There are some read requests waitng on finished stream')
+
-        );
+ChunkStream.prototype.destroy = function () {
+  if (!this._buffers) {
+    return;
+  }
+
+  this.writable = false;
+  this._reads = null;
+  this._buffers = null;
+
+  this.emit("close");
+};
+
+ChunkStream.prototype._processReadAllowingLess = function (read) {
+  // ok there is any data so that we can satisfy this request
+  this._reads.shift(); // == read
+
+  // first we need to peek into first buffer
+  let smallerBuf = this._buffers[0];
+
+  // ok there is more data than we need
+  if (smallerBuf.length > read.length) {
+    this._buffered -= read.length;
+    this._buffers[0] = smallerBuf.slice(read.length);
+
+    read.func.call(this, smallerBuf.slice(0, read.length));
+  } else {
+    // ok this is less than maximum length so use it all
+    this._buffered -= smallerBuf.length;
+    this._buffers.shift(); // == smallerBuf
+
+    read.func.call(this, smallerBuf);
+  }
+};
+
+ChunkStream.prototype._processRead = function (read) {
+  this._reads.shift(); // == read
+
+  let pos = 0;
+  let count = 0;
+  let data = Buffer.alloc(read.length);
+
+  // create buffer for all data
+  while (pos < read.length) {
+    let buf = this._buffers[count++];
+    let len = Math.min(buf.length, read.length - pos);
+
+    buf.copy(data, pos, 0, len);
+    pos += len;
+
+    // last buffer wasn't used all so just slice it and leave
+    if (len !== buf.length) {
+      this._buffers[--count] = buf.slice(len);
     }
+  }
 
-    this.destroy();
+  // remove all used buffers
+  if (count > 0) {
+    this._buffers.splice(0, count);
+  }
+
+  this._buffered -= read.length;
+
+  read.func.call(this, data);
 };
 
-ChunkStream.prototype.destroy = function() {
+ChunkStream.prototype._process = function () {
-
+  try {
-    if (!this._buffers) return;
-
-    this.writable = false;
-    this._reads = null;
-    this._buffers = null;
-
-    this.emit('close');
-};
-
-ChunkStream.prototype._process = function() {
-
     // as long as there is any data and read requests
     while (this._buffered > 0 && this._reads && this._reads.length > 0) {
+      let read = this._reads[0];
 
-        var read = this._reads[0];
+      // read any data (but no more than length)
+      if (read.allowLess) {
+        this._processReadAllowingLess(read);
+      } else if (this._buffered >= read.length) {
+        // ok we can meet some expectations
 
-        // read any data (but no more than length)
+        this._processRead(read);
-        if (read.allowLess) {
+      } else {
-
+        // not enought data to satisfy first request in queue
-            // ok there is any data so that we can satisfy this request
+        // so we need to wait for more
-            this._reads.shift(); // == read
+        break;
-
+      }
-            // first we need to peek into first buffer
-            var buf = this._buffers[0];
-
-            // ok there is more data than we need
-            if (buf.length > read.length) {
-
-                this._buffered -= read.length;
-                this._buffers[0] = buf.slice(read.length);
-
-                read.func.call(this, buf.slice(0, read.length));
-
-            } else {
-                // ok this is less than maximum length so use it all
-                this._buffered -= buf.length;
-                this._buffers.shift(); // == buf
-
-                read.func.call(this, buf);
-            }
-
-        } else if (this._buffered >= read.length) {
-            // ok we can meet some expectations
-
-            this._reads.shift(); // == read
-
-            var pos = 0,
-                count = 0,
-                data = new Buffer(read.length);
-
-            // create buffer for all data
-            while (pos < read.length) {
-
-                var buf = this._buffers[count++],
-                    len = Math.min(buf.length, read.length - pos);
-
-                buf.copy(data, pos, 0, len);
-                pos += len;
-
-                // last buffer wasn't used all so just slice it and leave
-                if (len != buf.length)
-                    this._buffers[--count] = buf.slice(len);
-            }
-
-            // remove all used buffers
-            if (count > 0)
-                this._buffers.splice(0, count);
-
-            this._buffered -= read.length;
-
-            read.func.call(this, data);
-
-        } else {
-            // not enought data to satisfy first request in queue
-            // so we need to wait for more
-            break;
-        }
     }
 
-    if (this._buffers && this._buffers.length > 0 && this._buffers[0] == null) {
+    if (this._buffers && !this.writable) {
-        this._end();
+      this._end();
     }
+  } catch (ex) {
+    this.emit("error", ex);
+  }
 };

lib/constants.js

@@ -1,38 +1,30 @@
-// Copyright (c) 2012 Kuba Niegowski
+export default {
-//
+  PNG_SIGNATURE: [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a],
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
 
-'use strict';
+  TYPE_IHDR: 0x49484452,
+  TYPE_IEND: 0x49454e44,
+  TYPE_IDAT: 0x49444154,
+  TYPE_PLTE: 0x504c5445,
+  TYPE_tRNS: 0x74524e53, // eslint-disable-line camelcase
+  TYPE_gAMA: 0x67414d41, // eslint-disable-line camelcase
 
+  // color-type bits
+  COLORTYPE_GRAYSCALE: 0,
+  COLORTYPE_PALETTE: 1,
+  COLORTYPE_COLOR: 2,
+  COLORTYPE_ALPHA: 4, // e.g. grayscale and alpha
 
-module.exports = {
+  // color-type combinations
+  COLORTYPE_PALETTE_COLOR: 3,
+  COLORTYPE_COLOR_ALPHA: 6,
 
-    PNG_SIGNATURE: [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a],
+  COLORTYPE_TO_BPP_MAP: {
+    0: 1,
+    2: 3,
+    3: 1,
+    4: 2,
+    6: 4,
+  },
 
-    TYPE_IHDR: 0x49484452,
+  GAMMA_DIVISION: 100000,
-    TYPE_IEND: 0x49454e44,
-    TYPE_IDAT: 0x49444154,
-    TYPE_PLTE: 0x504c5445,
-    TYPE_tRNS: 0x74524e53,
-    TYPE_gAMA: 0x67414d41,
-
-    COLOR_PALETTE: 1,
-    COLOR_COLOR: 2,
-    COLOR_ALPHA: 4
 };

lib/crc.js

@@ -1,79 +1,40 @@
-// Copyright (c) 2012 Kuba Niegowski
+let crcTable = [];
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
 
-'use strict';
+(function () {
-
+  for (let i = 0; i < 256; i++) {
-var util = require('util'),
+    let currentCrc = i;
-    Stream = require('stream');
+    for (let j = 0; j < 8; j++) {
-
+      if (currentCrc & 1) {
-
+        currentCrc = 0xedb88320 ^ (currentCrc >>> 1);
-var CrcStream = module.exports = function() {
+      } else {
-    Stream.call(this);
+        currentCrc = currentCrc >>> 1;
-
+      }
-    this._crc = -1;
-
-    this.writable = true;
-};
-util.inherits(CrcStream, Stream);
-
-
-CrcStream.prototype.write = function(data) {
-
-    for (var i = 0; i < data.length; i++) {
-        this._crc = crcTable[(this._crc ^ data[i]) & 0xff] ^ (this._crc >>> 8);
     }
-    return true;
+    crcTable[i] = currentCrc;
+  }
+})();
+
+let CrcCalculator = function () {
+  this._crc = -1;
 };
 
-CrcStream.prototype.end = function(data) {
+export default CrcCalculator;
-    if (data) this.write(data);
 
-    this.emit('crc', this.crc32());
+CrcCalculator.prototype.write = function (data) {
+  for (let i = 0; i < data.length; i++) {
+    this._crc = crcTable[(this._crc ^ data[i]) & 0xff] ^ (this._crc >>> 8);
+  }
+  return true;
 };
 
-CrcStream.prototype.crc32 = function() {
+CrcCalculator.prototype.crc32 = function () {
-    return this._crc ^ -1;
+  return this._crc ^ -1;
 };
 
-
+CrcCalculator.crc32 = function (buf) {
-CrcStream.crc32 = function(buf) {
+  let crc = -1;
-
+  for (let i = 0; i < buf.length; i++) {
-    var crc = -1;
+    crc = crcTable[(crc ^ buf[i]) & 0xff] ^ (crc >>> 8);
-    for (var i = 0; i < buf.length; i++) {
+  }
-        crc = crcTable[(crc ^ buf[i]) & 0xff] ^ (crc >>> 8);
+  return crc ^ -1;
-    }
-    return crc ^ -1;
 };
-
-
-
-var crcTable = [];
-
-for (var i = 0; i < 256; i++) {
-    var c = i;
-    for (var j = 0; j < 8; j++) {
-        if (c & 1) {
-            c = 0xedb88320 ^ (c >>> 1);
-        } else {
-            c = c >>> 1;
-        }
-    }
-    crcTable[i] = c;
-}

lib/filter-pack.js

@@ -0,0 +1,169 @@
+import paethPredictor from "./paeth-predictor.js";
+
+function filterNone(pxData, pxPos, byteWidth, rawData, rawPos) {
+  for (let x = 0; x < byteWidth; x++) {
+    rawData[rawPos + x] = pxData[pxPos + x];
+  }
+}
+
+function filterSumNone(pxData, pxPos, byteWidth) {
+  let sum = 0;
+  let length = pxPos + byteWidth;
+
+  for (let i = pxPos; i < length; i++) {
+    sum += Math.abs(pxData[i]);
+  }
+  return sum;
+}
+
+function filterSub(pxData, pxPos, byteWidth, rawData, rawPos, bpp) {
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let val = pxData[pxPos + x] - left;
+
+    rawData[rawPos + x] = val;
+  }
+}
+
+function filterSumSub(pxData, pxPos, byteWidth, bpp) {
+  let sum = 0;
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let val = pxData[pxPos + x] - left;
+
+    sum += Math.abs(val);
+  }
+
+  return sum;
+}
+
+function filterUp(pxData, pxPos, byteWidth, rawData, rawPos) {
+  for (let x = 0; x < byteWidth; x++) {
+    let up = pxPos > 0 ? pxData[pxPos + x - byteWidth] : 0;
+    let val = pxData[pxPos + x] - up;
+
+    rawData[rawPos + x] = val;
+  }
+}
+
+function filterSumUp(pxData, pxPos, byteWidth) {
+  let sum = 0;
+  let length = pxPos + byteWidth;
+  for (let x = pxPos; x < length; x++) {
+    let up = pxPos > 0 ? pxData[x - byteWidth] : 0;
+    let val = pxData[x] - up;
+
+    sum += Math.abs(val);
+  }
+
+  return sum;
+}
+
+function filterAvg(pxData, pxPos, byteWidth, rawData, rawPos, bpp) {
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let up = pxPos > 0 ? pxData[pxPos + x - byteWidth] : 0;
+    let val = pxData[pxPos + x] - ((left + up) >> 1);
+
+    rawData[rawPos + x] = val;
+  }
+}
+
+function filterSumAvg(pxData, pxPos, byteWidth, bpp) {
+  let sum = 0;
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let up = pxPos > 0 ? pxData[pxPos + x - byteWidth] : 0;
+    let val = pxData[pxPos + x] - ((left + up) >> 1);
+
+    sum += Math.abs(val);
+  }
+
+  return sum;
+}
+
+function filterPaeth(pxData, pxPos, byteWidth, rawData, rawPos, bpp) {
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let up = pxPos > 0 ? pxData[pxPos + x - byteWidth] : 0;
+    let upleft =
+      pxPos > 0 && x >= bpp ? pxData[pxPos + x - (byteWidth + bpp)] : 0;
+    let val = pxData[pxPos + x] - paethPredictor(left, up, upleft);
+
+    rawData[rawPos + x] = val;
+  }
+}
+
+function filterSumPaeth(pxData, pxPos, byteWidth, bpp) {
+  let sum = 0;
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let up = pxPos > 0 ? pxData[pxPos + x - byteWidth] : 0;
+    let upleft =
+      pxPos > 0 && x >= bpp ? pxData[pxPos + x - (byteWidth + bpp)] : 0;
+    let val = pxData[pxPos + x] - paethPredictor(left, up, upleft);
+
+    sum += Math.abs(val);
+  }
+
+  return sum;
+}
+
+let filters = {
+  0: filterNone,
+  1: filterSub,
+  2: filterUp,
+  3: filterAvg,
+  4: filterPaeth,
+};
+
+let filterSums = {
+  0: filterSumNone,
+  1: filterSumSub,
+  2: filterSumUp,
+  3: filterSumAvg,
+  4: filterSumPaeth,
+};
+
+export default function (pxData, width, height, options, bpp) {
+  let filterTypes;
+  if (!("filterType" in options) || options.filterType === -1) {
+    filterTypes = [0, 1, 2, 3, 4];
+  } else if (typeof options.filterType === "number") {
+    filterTypes = [options.filterType];
+  } else {
+    throw new Error("unrecognised filter types");
+  }
+
+  if (options.bitDepth === 16) {
+    bpp *= 2;
+  }
+  let byteWidth = width * bpp;
+  let rawPos = 0;
+  let pxPos = 0;
+  let rawData = Buffer.alloc((byteWidth + 1) * height);
+
+  let sel = filterTypes[0];
+
+  for (let y = 0; y < height; y++) {
+    if (filterTypes.length > 1) {
+      // find best filter for this line (with lowest sum of values)
+      let min = Infinity;
+
+      for (let i = 0; i < filterTypes.length; i++) {
+        let sum = filterSums[filterTypes[i]](pxData, pxPos, byteWidth, bpp);
+        if (sum < min) {
+          sel = filterTypes[i];
+          min = sum;
+        }
+      }
+    }
+
+    rawData[rawPos] = sel;
+    rawPos++;
+    filters[sel](pxData, pxPos, byteWidth, rawData, rawPos, bpp);
+    rawPos += byteWidth;
+    pxPos += byteWidth;
+  }
+  return rawData;
+};

lib/filter-parse-async.js

@@ -0,0 +1,24 @@
+import ChunkStream from "./chunkstream.js";
+import Filter from "./filter-parse.js";
+let util = require("util");
+
+let FilterAsync = function (bitmapInfo) {
+  ChunkStream.call(this);
+
+  let buffers = [];
+  let that = this;
+  this._filter = new Filter(bitmapInfo, {
+    read: this.read.bind(this),
+    write: function (buffer) {
+      buffers.push(buffer);
+    },
+    complete: function () {
+      that.emit("complete", Buffer.concat(buffers));
+    },
+  });
+
+  this._filter.start();
+};
+util.inherits(FilterAsync, ChunkStream);
+
+export default FilterAsync;

lib/filter-parse-sync.js

@@ -0,0 +1,19 @@
+import SyncReader from "./sync-reader.js";
+import Filter from "./filter-parse.js";
+
+export default function (inBuffer, bitmapInfo) {
+  let outBuffers = [];
+  let reader = new SyncReader(inBuffer);
+  let filter = new Filter(bitmapInfo, {
+    read: reader.read.bind(reader),
+    write: function (bufferPart) {
+      outBuffers.push(bufferPart);
+    },
+    complete: function () {},
+  });
+
+  filter.start();
+  reader.process();
+
+  return Buffer.concat(outBuffers);
+};

lib/filter-parse.js

@@ -0,0 +1,177 @@
+import interlaceUtils from "./interlace.js";
+import paethPredictor from "./paeth-predictor.js";
+
+function getByteWidth(width, bpp, depth) {
+  let byteWidth = width * bpp;
+  if (depth !== 8) {
+    byteWidth = Math.ceil(byteWidth / (8 / depth));
+  }
+  return byteWidth;
+}
+
+let Filter = function (bitmapInfo, dependencies) {
+  let width = bitmapInfo.width;
+  let height = bitmapInfo.height;
+  let interlace = bitmapInfo.interlace;
+  let bpp = bitmapInfo.bpp;
+  let depth = bitmapInfo.depth;
+
+  this.read = dependencies.read;
+  this.write = dependencies.write;
+  this.complete = dependencies.complete;
+
+  this._imageIndex = 0;
+  this._images = [];
+  if (interlace) {
+    let passes = interlaceUtils.getImagePasses(width, height);
+    for (let i = 0; i < passes.length; i++) {
+      this._images.push({
+        byteWidth: getByteWidth(passes[i].width, bpp, depth),
+        height: passes[i].height,
+        lineIndex: 0,
+      });
+    }
+  } else {
+    this._images.push({
+      byteWidth: getByteWidth(width, bpp, depth),
+      height: height,
+      lineIndex: 0,
+    });
+  }
+
+  // when filtering the line we look at the pixel to the left
+  // the spec also says it is done on a byte level regardless of the number of pixels
+  // so if the depth is byte compatible (8 or 16) we subtract the bpp in order to compare back
+  // a pixel rather than just a different byte part. However if we are sub byte, we ignore.
+  if (depth === 8) {
+    this._xComparison = bpp;
+  } else if (depth === 16) {
+    this._xComparison = bpp * 2;
+  } else {
+    this._xComparison = 1;
+  }
+};
+
+export default Filter;
+
+Filter.prototype.start = function () {
+  this.read(
+    this._images[this._imageIndex].byteWidth + 1,
+    this._reverseFilterLine.bind(this)
+  );
+};
+
+Filter.prototype._unFilterType1 = function (
+  rawData,
+  unfilteredLine,
+  byteWidth
+) {
+  let xComparison = this._xComparison;
+  let xBiggerThan = xComparison - 1;
+
+  for (let x = 0; x < byteWidth; x++) {
+    let rawByte = rawData[1 + x];
+    let f1Left = x > xBiggerThan ? unfilteredLine[x - xComparison] : 0;
+    unfilteredLine[x] = rawByte + f1Left;
+  }
+};
+
+Filter.prototype._unFilterType2 = function (
+  rawData,
+  unfilteredLine,
+  byteWidth
+) {
+  let lastLine = this._lastLine;
+
+  for (let x = 0; x < byteWidth; x++) {
+    let rawByte = rawData[1 + x];
+    let f2Up = lastLine ? lastLine[x] : 0;
+    unfilteredLine[x] = rawByte + f2Up;
+  }
+};
+
+Filter.prototype._unFilterType3 = function (
+  rawData,
+  unfilteredLine,
+  byteWidth
+) {
+  let xComparison = this._xComparison;
+  let xBiggerThan = xComparison - 1;
+  let lastLine = this._lastLine;
+
+  for (let x = 0; x < byteWidth; x++) {
+    let rawByte = rawData[1 + x];
+    let f3Up = lastLine ? lastLine[x] : 0;
+    let f3Left = x > xBiggerThan ? unfilteredLine[x - xComparison] : 0;
+    let f3Add = Math.floor((f3Left + f3Up) / 2);
+    unfilteredLine[x] = rawByte + f3Add;
+  }
+};
+
+Filter.prototype._unFilterType4 = function (
+  rawData,
+  unfilteredLine,
+  byteWidth
+) {
+  let xComparison = this._xComparison;
+  let xBiggerThan = xComparison - 1;
+  let lastLine = this._lastLine;
+
+  for (let x = 0; x < byteWidth; x++) {
+    let rawByte = rawData[1 + x];
+    let f4Up = lastLine ? lastLine[x] : 0;
+    let f4Left = x > xBiggerThan ? unfilteredLine[x - xComparison] : 0;
+    let f4UpLeft = x > xBiggerThan && lastLine ? lastLine[x - xComparison] : 0;
+    let f4Add = paethPredictor(f4Left, f4Up, f4UpLeft);
+    unfilteredLine[x] = rawByte + f4Add;
+  }
+};
+
+Filter.prototype._reverseFilterLine = function (rawData) {
+  let filter = rawData[0];
+  let unfilteredLine;
+  let currentImage = this._images[this._imageIndex];
+  let byteWidth = currentImage.byteWidth;
+
+  if (filter === 0) {
+    unfilteredLine = rawData.slice(1, byteWidth + 1);
+  } else {
+    unfilteredLine = Buffer.alloc(byteWidth);
+
+    switch (filter) {
+      case 1:
+        this._unFilterType1(rawData, unfilteredLine, byteWidth);
+        break;
+      case 2:
+        this._unFilterType2(rawData, unfilteredLine, byteWidth);
+        break;
+      case 3:
+        this._unFilterType3(rawData, unfilteredLine, byteWidth);
+        break;
+      case 4:
+        this._unFilterType4(rawData, unfilteredLine, byteWidth);
+        break;
+      default:
+        throw new Error("Unrecognised filter type - " + filter);
+    }
+  }
+
+  this.write(unfilteredLine);
+
+  currentImage.lineIndex++;
+  if (currentImage.lineIndex >= currentImage.height) {
+    this._lastLine = null;
+    this._imageIndex++;
+    currentImage = this._images[this._imageIndex];
+  } else {
+    this._lastLine = unfilteredLine;
+  }
+
+  if (currentImage) {
+    // read, using the byte width that may be from the new current image
+    this.read(currentImage.byteWidth + 1, this._reverseFilterLine.bind(this));
+  } else {
+    this._lastLine = null;
+    this.complete();
+  }
+};

lib/filter.js

@@ -1,314 +0,0 @@
-// Copyright (c) 2012 Kuba Niegowski
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-'use strict';
-
-var util = require('util'),
-    zlib = require('zlib'),
-    ChunkStream = require('./chunkstream');
-
-
-var Filter = module.exports = function(width, height, Bpp, data, options) {
-    ChunkStream.call(this);
-
-    this._width = width;
-    this._height = height;
-    this._Bpp = Bpp;
-    this._data = data;
-    this._options = options;
-
-    this._line = 0;
-
-    if (!('filterType' in options) || options.filterType == -1) {
-        options.filterType = [0, 1, 2, 3, 4];
-    } else if (typeof options.filterType == 'number') {
-        options.filterType = [options.filterType];
-    }
-
-    this._filters = {
-        0: this._filterNone.bind(this),
-        1: this._filterSub.bind(this),
-        2: this._filterUp.bind(this),
-        3: this._filterAvg.bind(this),
-        4: this._filterPaeth.bind(this)
-    };
-
-    this.read(this._width * Bpp + 1, this._reverseFilterLine.bind(this));
-};
-util.inherits(Filter, ChunkStream);
-
-
-var pixelBppMap = {
-    1: { // L
-        0: 0,
-        1: 0,
-        2: 0,
-        3: 0xff
-    },
-    2: { // LA
-        0: 0,
-        1: 0,
-        2: 0,
-        3: 1
-    },
-    3: { // RGB
-        0: 0,
-        1: 1,
-        2: 2,
-        3: 0xff
-    },
-    4: { // RGBA
-        0: 0,
-        1: 1,
-        2: 2,
-        3: 3
-    }
-};
-
-Filter.prototype._reverseFilterLine = function(rawData) {
-
-    var pxData = this._data,
-        pxLineLength = this._width << 2,
-        pxRowPos = this._line * pxLineLength,
-        filter = rawData[0];
-
-    if (filter == 0) {
-        for (var x = 0; x < this._width; x++) {
-            var pxPos = pxRowPos + (x << 2),
-                rawPos = 1 + x * this._Bpp;
-
-            for (var i = 0; i < 4; i++) {
-                var idx = pixelBppMap[this._Bpp][i];
-                pxData[pxPos + i] = idx != 0xff ? rawData[rawPos + idx] : 0xff;
-            }
-        }
-
-    } else if (filter == 1) {
-        for (var x = 0; x < this._width; x++) {
-            var pxPos = pxRowPos + (x << 2),
-                rawPos = 1 + x * this._Bpp;
-
-            for (var i = 0; i < 4; i++) {
-                var idx = pixelBppMap[this._Bpp][i],
-                    left = x > 0 ? pxData[pxPos + i - 4] : 0;
-
-                pxData[pxPos + i] = idx != 0xff ? rawData[rawPos + idx] + left : 0xff;
-            }
-        }
-
-    } else if (filter == 2) {
-        for (var x = 0; x < this._width; x++) {
-            var pxPos = pxRowPos + (x << 2),
-                rawPos = 1 + x * this._Bpp;
-
-            for (var i = 0; i < 4; i++) {
-                var idx = pixelBppMap[this._Bpp][i],
-                    up = this._line > 0 ? pxData[pxPos - pxLineLength + i] : 0;
-
-                pxData[pxPos + i] = idx != 0xff ? rawData[rawPos + idx] + up : 0xff;
-            }
-
-        }
-
-    } else if (filter == 3) {
-        for (var x = 0; x < this._width; x++) {
-            var pxPos = pxRowPos + (x << 2),
-                rawPos = 1 + x * this._Bpp;
-
-            for (var i = 0; i < 4; i++) {
-                var idx = pixelBppMap[this._Bpp][i],
-                    left = x > 0 ? pxData[pxPos + i - 4] : 0,
-                    up = this._line > 0 ? pxData[pxPos - pxLineLength + i] : 0,
-                    add = Math.floor((left + up) / 2);
-
-                 pxData[pxPos + i] = idx != 0xff ? rawData[rawPos + idx] + add : 0xff;
-            }
-
-        }
-
-    } else if (filter == 4) {
-        for (var x = 0; x < this._width; x++) {
-            var pxPos = pxRowPos + (x << 2),
-                rawPos = 1 + x * this._Bpp;
-
-            for (var i = 0; i < 4; i++) {
-                var idx = pixelBppMap[this._Bpp][i],
-                    left = x > 0 ? pxData[pxPos + i - 4] : 0,
-                    up = this._line > 0 ? pxData[pxPos - pxLineLength + i] : 0,
-                    upLeft = x > 0 && this._line > 0
-                            ? pxData[pxPos - pxLineLength + i - 4] : 0,
-                    add = PaethPredictor(left, up, upLeft);
-
-                pxData[pxPos + i] = idx != 0xff ? rawData[rawPos + idx] + add : 0xff;
-            }
-        }
-    }
-
-
-    this._line++;
-
-    if (this._line < this._height)
-        this.read(this._width * this._Bpp + 1, this._reverseFilterLine.bind(this));
-    else
-        this.emit('complete', this._data, this._width, this._height);
-};
-
-
-
-
-Filter.prototype.filter = function() {
-
-    var pxData = this._data,
-        rawData = new Buffer(((this._width << 2) + 1) * this._height);
-
-    for (var y = 0; y < this._height; y++) {
-
-        // find best filter for this line (with lowest sum of values)
-        var filterTypes = this._options.filterType,
-            min = Infinity,
-            sel = 0;
-
-        for (var i = 0; i < filterTypes.length; i++) {
-            var sum = this._filters[filterTypes[i]](pxData, y, null);
-            if (sum < min) {
-                sel = filterTypes[i];
-                min = sum;
-            }
-        }
-
-        this._filters[sel](pxData, y, rawData);
-    }
-    return rawData;
-};
-
-Filter.prototype._filterNone = function(pxData, y, rawData) {
-
-    var pxRowLength = this._width << 2,
-        rawRowLength = pxRowLength + 1,
-        sum = 0;
-
-    if (!rawData) {
-        for (var x = 0; x < pxRowLength; x++)
-            sum += Math.abs(pxData[y * pxRowLength + x]);
-
-    } else {
-        rawData[y * rawRowLength] = 0;
-        pxData.copy(rawData, rawRowLength * y + 1, pxRowLength * y, pxRowLength * (y + 1));
-    }
-
-    return sum;
-};
-
-Filter.prototype._filterSub = function(pxData, y, rawData) {
-
-    var pxRowLength = this._width << 2,
-        rawRowLength = pxRowLength + 1,
-        sum = 0;
-
-    if (rawData)
-        rawData[y * rawRowLength] = 1;
-
-    for (var x = 0; x < pxRowLength; x++) {
-
-        var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0,
-            val = pxData[y * pxRowLength + x] - left;
-
-        if (!rawData) sum += Math.abs(val);
-        else rawData[y * rawRowLength + 1 + x] = val;
-    }
-    return sum;
-};
-
-Filter.prototype._filterUp = function(pxData, y, rawData) {
-
-    var pxRowLength = this._width << 2,
-        rawRowLength = pxRowLength + 1,
-        sum = 0;
-
-    if (rawData)
-        rawData[y * rawRowLength] = 2;
-
-    for (var x = 0; x < pxRowLength; x++) {
-
-        var up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0,
-            val = pxData[y * pxRowLength + x] - up;
-
-        if (!rawData) sum += Math.abs(val);
-        else rawData[y * rawRowLength + 1 + x] = val;
-    }
-    return sum;
-};
-
-Filter.prototype._filterAvg = function(pxData, y, rawData) {
-
-    var pxRowLength = this._width << 2,
-        rawRowLength = pxRowLength + 1,
-        sum = 0;
-
-    if (rawData)
-        rawData[y * rawRowLength] = 3;
-
-    for (var x = 0; x < pxRowLength; x++) {
-
-        var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0,
-            up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0,
-            val = pxData[y * pxRowLength + x] - ((left + up) >> 1);
-
-        if (!rawData) sum += Math.abs(val);
-        else rawData[y * rawRowLength + 1 + x] = val;
-    }
-    return sum;
-};
-
-Filter.prototype._filterPaeth = function(pxData, y, rawData) {
-
-    var pxRowLength = this._width << 2,
-        rawRowLength = pxRowLength + 1,
-        sum = 0;
-
-    if (rawData)
-        rawData[y * rawRowLength] = 4;
-
-    for (var x = 0; x < pxRowLength; x++) {
-
-        var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0,
-            up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0,
-            upLeft = x >= 4 && y > 0 ? pxData[(y - 1) * pxRowLength + x - 4] : 0,
-            val = pxData[y * pxRowLength + x] - PaethPredictor(left, up, upLeft);
-
-        if (!rawData) sum += Math.abs(val);
-        else rawData[y * rawRowLength + 1 + x] = val;
-    }
-    return sum;
-};
-
-
-
-var PaethPredictor = function(left, above, upLeft) {
-
-    var p = left + above - upLeft,
-        pLeft = Math.abs(p - left),
-        pAbove = Math.abs(p - above),
-        pUpLeft = Math.abs(p - upLeft);
-
-    if (pLeft <= pAbove && pLeft <= pUpLeft) return left;
-    else if (pAbove <= pUpLeft) return above;
-    else return upLeft;
-};

lib/format-normaliser.js

@@ -0,0 +1,91 @@
+function dePalette(indata, outdata, width, height, palette) {
+  let pxPos = 0;
+  // use values from palette
+  for (let y = 0; y < height; y++) {
+    for (let x = 0; x < width; x++) {
+      let color = palette[indata[pxPos]];
+
+      if (!color) {
+        throw new Error("index " + indata[pxPos] + " not in palette");
+      }
+
+      for (let i = 0; i < 4; i++) {
+        outdata[pxPos + i] = color[i];
+      }
+      pxPos += 4;
+    }
+  }
+}
+
+function replaceTransparentColor(indata, outdata, width, height, transColor) {
+  let pxPos = 0;
+  for (let y = 0; y < height; y++) {
+    for (let x = 0; x < width; x++) {
+      let makeTrans = false;
+
+      if (transColor.length === 1) {
+        if (transColor[0] === indata[pxPos]) {
+          makeTrans = true;
+        }
+      } else if (
+        transColor[0] === indata[pxPos] &&
+        transColor[1] === indata[pxPos + 1] &&
+        transColor[2] === indata[pxPos + 2]
+      ) {
+        makeTrans = true;
+      }
+      if (makeTrans) {
+        for (let i = 0; i < 4; i++) {
+          outdata[pxPos + i] = 0;
+        }
+      }
+      pxPos += 4;
+    }
+  }
+}
+
+function scaleDepth(indata, outdata, width, height, depth) {
+  let maxOutSample = 255;
+  let maxInSample = Math.pow(2, depth) - 1;
+  let pxPos = 0;
+
+  for (let y = 0; y < height; y++) {
+    for (let x = 0; x < width; x++) {
+      for (let i = 0; i < 4; i++) {
+        outdata[pxPos + i] = Math.floor(
+          (indata[pxPos + i] * maxOutSample) / maxInSample + 0.5
+        );
+      }
+      pxPos += 4;
+    }
+  }
+}
+
+export default function (indata, imageData) {
+  let depth = imageData.depth;
+  let width = imageData.width;
+  let height = imageData.height;
+  let colorType = imageData.colorType;
+  let transColor = imageData.transColor;
+  let palette = imageData.palette;
+
+  let outdata = indata; // only different for 16 bits
+
+  if (colorType === 3) {
+    // paletted
+    dePalette(indata, outdata, width, height, palette);
+  } else {
+    if (transColor) {
+      replaceTransparentColor(indata, outdata, width, height, transColor);
+    }
+    // if it needs scaling
+    if (depth !== 8) {
+      // if we need to change the buffer size
+      if (depth === 16) {
+        outdata = Buffer.alloc(width * height * 4);
+      }
+      scaleDepth(indata, outdata, width, height, depth);
+    }
+  }
+  return outdata;
+};

lib/interlace.js

@@ -0,0 +1,98 @@
+// Adam 7
+//   0 1 2 3 4 5 6 7
+// 0 x 6 4 6 x 6 4 6
+// 1 7 7 7 7 7 7 7 7
+// 2 5 6 5 6 5 6 5 6
+// 3 7 7 7 7 7 7 7 7
+// 4 3 6 4 6 3 6 4 6
+// 5 7 7 7 7 7 7 7 7
+// 6 5 6 5 6 5 6 5 6
+// 7 7 7 7 7 7 7 7 7
+
+let imagePasses = [
+  {
+    // pass 1 - 1px
+    x: [0],
+    y: [0],
+  },
+  {
+    // pass 2 - 1px
+    x: [4],
+    y: [0],
+  },
+  {
+    // pass 3 - 2px
+    x: [0, 4],
+    y: [4],
+  },
+  {
+    // pass 4 - 4px
+    x: [2, 6],
+    y: [0, 4],
+  },
+  {
+    // pass 5 - 8px
+    x: [0, 2, 4, 6],
+    y: [2, 6],
+  },
+  {
+    // pass 6 - 16px
+    x: [1, 3, 5, 7],
+    y: [0, 2, 4, 6],
+  },
+  {
+    // pass 7 - 32px
+    x: [0, 1, 2, 3, 4, 5, 6, 7],
+    y: [1, 3, 5, 7],
+  },
+];
+
+export var getImagePasses = function (width, height) {
+  let images = [];
+  let xLeftOver = width % 8;
+  let yLeftOver = height % 8;
+  let xRepeats = (width - xLeftOver) / 8;
+  let yRepeats = (height - yLeftOver) / 8;
+  for (let i = 0; i < imagePasses.length; i++) {
+    let pass = imagePasses[i];
+    let passWidth = xRepeats * pass.x.length;
+    let passHeight = yRepeats * pass.y.length;
+    for (let j = 0; j < pass.x.length; j++) {
+      if (pass.x[j] < xLeftOver) {
+        passWidth++;
+      } else {
+        break;
+      }
+    }
+    for (let j = 0; j < pass.y.length; j++) {
+      if (pass.y[j] < yLeftOver) {
+        passHeight++;
+      } else {
+        break;
+      }
+    }
+    if (passWidth > 0 && passHeight > 0) {
+      images.push({ width: passWidth, height: passHeight, index: i });
+    }
+  }
+  return images;
+};
+
+export var getInterlaceIterator = function (width) {
+  return function (x, y, pass) {
+    let outerXLeftOver = x % imagePasses[pass].x.length;
+    let outerX =
+      ((x - outerXLeftOver) / imagePasses[pass].x.length) * 8 +
+      imagePasses[pass].x[outerXLeftOver];
+    let outerYLeftOver = y % imagePasses[pass].y.length;
+    let outerY =
+      ((y - outerYLeftOver) / imagePasses[pass].y.length) * 8 +
+      imagePasses[pass].y[outerYLeftOver];
+    return outerX * 4 + outerY * width * 4;
+  };
+};
+
+export default {
+  getImagePasses,
+  getInterlaceIterator
+}

lib/packer-async.js

@@ -0,0 +1,51 @@
+let util = require("util");
+let Stream = require("stream");
+
+import constants from "./constants.js";
+import Packer from "./packer.js";
+
+let PackerAsync = function (opt) {
+  Stream.call(this);
+
+  let options = opt || {};
+
+  this._packer = new Packer(options);
+  this._deflate = this._packer.createDeflate();
+
+  this.readable = true;
+};
+util.inherits(PackerAsync, Stream);
+
+export default PackerAsync;
+
+PackerAsync.prototype.pack = function (data, width, height, gamma) {
+  // Signature
+  this.emit("data", Buffer.from(constants.PNG_SIGNATURE));
+  this.emit("data", this._packer.packIHDR(width, height));
+
+  if (gamma) {
+    this.emit("data", this._packer.packGAMA(gamma));
+  }
+
+  let filteredData = this._packer.filterData(data, width, height);
+
+  // compress it
+  this._deflate.on("error", this.emit.bind(this, "error"));
+
+  this._deflate.on(
+    "data",
+    function (compressedData) {
+      this.emit("data", this._packer.packIDAT(compressedData));
+    }.bind(this)
+  );
+
+  this._deflate.on(
+    "end",
+    function () {
+      this.emit("data", this._packer.packIEND());
+      this.emit("end");
+    }.bind(this)
+  );
+
+  this._deflate.end(filteredData);
+};

lib/packer-sync.js

@@ -0,0 +1,52 @@
+import constants from "./constants.js";
+import Packer from "./packer.js";
+
+let hasSyncZlib = true;
+let zlib = require("zlib");
+
+export default function (metaData, opt) {
+  if (!hasSyncZlib) {
+    throw new Error(
+      "To use the sync capability of this library in old node versions, please pin pngjs to v2.3.0"
+    );
+  }
+
+  let options = opt || {};
+
+  let packer = new Packer(options);
+
+  let chunks = [];
+
+  // Signature
+  chunks.push(Buffer.from(constants.PNG_SIGNATURE));
+
+  // Header
+  chunks.push(packer.packIHDR(metaData.width, metaData.height));
+
+  if (metaData.gamma) {
+    chunks.push(packer.packGAMA(metaData.gamma));
+  }
+
+  let filteredData = packer.filterData(
+    metaData.data,
+    metaData.width,
+    metaData.height
+  );
+
+  // compress it
+  let compressedData = zlib.deflateSync(
+    filteredData,
+    packer.getDeflateOptions()
+  );
+  filteredData = null;
+
+  if (!compressedData || !compressedData.length) {
+    throw new Error("bad png - invalid compressed data response");
+  }
+  chunks.push(packer.packIDAT(compressedData));
+
+  // End
+  chunks.push(packer.packIEND());
+
+  return Buffer.concat(chunks);
+};

lib/packer.js

@@ -1,110 +1,130 @@
-// Copyright (c) 2012 Kuba Niegowski
+import constants from "./constants.js";
-//
+import CrcStream from "./crc.js";
-// Permission is hereby granted, free of charge, to any person obtaining a copy
+import bitPacker from "./bitpacker.js";
-// of this software and associated documentation files (the "Software"), to deal
+import filter from "./filter-pack.js";
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
 
-'use strict';
+let zlib = require("zlib");
 
+let Packer = function (options) {
+  this._options = options;
 
-var util = require('util'),
+  options.deflateChunkSize = options.deflateChunkSize || 32 * 1024;
-    Stream = require('stream'),
+  options.deflateLevel =
-    zlib = require('zlib'),
+    options.deflateLevel != null ? options.deflateLevel : 9;
-    Filter = require('./filter'),
+  options.deflateStrategy =
-    CrcStream = require('./crc'),
+    options.deflateStrategy != null ? options.deflateStrategy : 3;
-    constants = require('./constants');
+  options.inputHasAlpha =
+    options.inputHasAlpha != null ? options.inputHasAlpha : true;
+  options.deflateFactory = options.deflateFactory || zlib.createDeflate;
+  options.bitDepth = options.bitDepth || 8;
+  // This is outputColorType
+  options.colorType =
+    typeof options.colorType === "number"
+      ? options.colorType
+      : constants.COLORTYPE_COLOR_ALPHA;
+  options.inputColorType =
+    typeof options.inputColorType === "number"
+      ? options.inputColorType
+      : constants.COLORTYPE_COLOR_ALPHA;
 
-
+  if (
-var Packer = module.exports = function(options) {
+    [
-    Stream.call(this);
+      constants.COLORTYPE_GRAYSCALE,
-
+      constants.COLORTYPE_COLOR,
-    this._options = options;
+      constants.COLORTYPE_COLOR_ALPHA,
-
+      constants.COLORTYPE_ALPHA,
-    options.deflateChunkSize = options.deflateChunkSize || 32 * 1024;
+    ].indexOf(options.colorType) === -1
-    options.deflateLevel = options.deflateLevel || 9;
+  ) {
-    options.deflateStrategy = options.deflateStrategy || 3;
+    throw new Error(
-
+      "option color type:" + options.colorType + " is not supported at present"
-    this.readable = true;
+    );
-};
+  }
-util.inherits(Packer, Stream);
+  if (
-
+    [
-
+      constants.COLORTYPE_GRAYSCALE,
-Packer.prototype.pack = function(data, width, height) {
+      constants.COLORTYPE_COLOR,
-
+      constants.COLORTYPE_COLOR_ALPHA,
-    // Signature
+      constants.COLORTYPE_ALPHA,
-    this.emit('data', new Buffer(constants.PNG_SIGNATURE));
+    ].indexOf(options.inputColorType) === -1
-    this.emit('data', this._packIHDR(width, height));
+  ) {
-
+    throw new Error(
-    // filter pixel data
+      "option input color type:" +
-    var filter = new Filter(width, height, 4, data, this._options);
+        options.inputColorType +
-    var data = filter.filter();
+        " is not supported at present"
-
+    );
-    // compress it
+  }
-    var deflate = zlib.createDeflate({
+  if (options.bitDepth !== 8 && options.bitDepth !== 16) {
-            chunkSize: this._options.deflateChunkSize,
+    throw new Error(
-            level: this._options.deflateLevel,
+      "option bit depth:" + options.bitDepth + " is not supported at present"
-            strategy: this._options.deflateStrategy
+    );
-        });
+  }
-    deflate.on('error', this.emit.bind(this, 'error'));
-
-    deflate.on('data', function(data) {
-        this.emit('data', this._packIDAT(data));
-    }.bind(this));
-
-    deflate.on('end', function() {
-        this.emit('data', this._packIEND());
-        this.emit('end');
-    }.bind(this));
-
-    deflate.end(data);
 };
 
-Packer.prototype._packChunk = function(type, data) {
+export default Packer;
 
-    var len = (data ? data.length : 0),
+Packer.prototype.getDeflateOptions = function () {
-        buf = new Buffer(len + 12);
+  return {
-
+    chunkSize: this._options.deflateChunkSize,
-    buf.writeUInt32BE(len, 0);
+    level: this._options.deflateLevel,
-    buf.writeUInt32BE(type, 4);
+    strategy: this._options.deflateStrategy,
-
+  };
-    if (data) data.copy(buf, 8);
-
-    buf.writeInt32BE(CrcStream.crc32(buf.slice(4, buf.length - 4)), buf.length - 4);
-    return buf;
 };
 
-Packer.prototype._packIHDR = function(width, height) {
+Packer.prototype.createDeflate = function () {
-
+  return this._options.deflateFactory(this.getDeflateOptions());
-    var buf = new Buffer(13);
-    buf.writeUInt32BE(width, 0);
-    buf.writeUInt32BE(height, 4);
-    buf[8] = 8;
-    buf[9] = 6; // colorType
-    buf[10] = 0; // compression
-    buf[11] = 0; // filter
-    buf[12] = 0; // interlace
-
-    return this._packChunk(constants.TYPE_IHDR, buf);
 };
 
-Packer.prototype._packIDAT = function(data) {
+Packer.prototype.filterData = function (data, width, height) {
-    return this._packChunk(constants.TYPE_IDAT, data);
+  // convert to correct format for filtering (e.g. right bpp and bit depth)
+  let packedData = bitPacker(data, width, height, this._options);
+
+  // filter pixel data
+  let bpp = constants.COLORTYPE_TO_BPP_MAP[this._options.colorType];
+  let filteredData = filter(packedData, width, height, this._options, bpp);
+  return filteredData;
 };
 
-Packer.prototype._packIEND = function() {
+Packer.prototype._packChunk = function (type, data) {
-    return this._packChunk(constants.TYPE_IEND, null);
+  let len = data ? data.length : 0;
+  let buf = Buffer.alloc(len + 12);
+
+  buf.writeUInt32BE(len, 0);
+  buf.writeUInt32BE(type, 4);
+
+  if (data) {
+    data.copy(buf, 8);
+  }
+
+  buf.writeInt32BE(
+    CrcStream.crc32(buf.slice(4, buf.length - 4)),
+    buf.length - 4
+  );
+  return buf;
+};
+
+Packer.prototype.packGAMA = function (gamma) {
+  let buf = Buffer.alloc(4);
+  buf.writeUInt32BE(Math.floor(gamma * constants.GAMMA_DIVISION), 0);
+  return this._packChunk(constants.TYPE_gAMA, buf);
+};
+
+Packer.prototype.packIHDR = function (width, height) {
+  let buf = Buffer.alloc(13);
+  buf.writeUInt32BE(width, 0);
+  buf.writeUInt32BE(height, 4);
+  buf[8] = this._options.bitDepth; // Bit depth
+  buf[9] = this._options.colorType; // colorType
+  buf[10] = 0; // compression
+  buf[11] = 0; // filter
+  buf[12] = 0; // interlace
+
+  return this._packChunk(constants.TYPE_IHDR, buf);
+};
+
+Packer.prototype.packIDAT = function (data) {
+  return this._packChunk(constants.TYPE_IDAT, data);
+};
+
+Packer.prototype.packIEND = function () {
+  return this._packChunk(constants.TYPE_IEND, null);
 };

lib/paeth-predictor.js

@@ -0,0 +1,14 @@
+export default function paethPredictor(left, above, upLeft) {
+  let paeth = left + above - upLeft;
+  let pLeft = Math.abs(paeth - left);
+  let pAbove = Math.abs(paeth - above);
+  let pUpLeft = Math.abs(paeth - upLeft);
+
+  if (pLeft <= pAbove && pLeft <= pUpLeft) {
+    return left;
+  }
+  if (pAbove <= pUpLeft) {
+    return above;
+  }
+  return upLeft;
+};

lib/parser-async.js

@@ -0,0 +1,166 @@
+import ChunkStream from "./chunkstream.js";
+import FilterAsync from "./filter-parse-async.js";
+import Parser from "./parser.js";
+import bitmapper from "./bitmapper.js";
+import formatNormaliser from "./format-normaliser.js";
+
+let util = require("util");
+let zlib = require("zlib");
+
+let ParserAsync = function (options) {
+  ChunkStream.call(this);
+
+  this._parser = new Parser(options, {
+    read: this.read.bind(this),
+    error: this._handleError.bind(this),
+    metadata: this._handleMetaData.bind(this),
+    gamma: this.emit.bind(this, "gamma"),
+    palette: this._handlePalette.bind(this),
+    transColor: this._handleTransColor.bind(this),
+    finished: this._finished.bind(this),
+    inflateData: this._inflateData.bind(this),
+    simpleTransparency: this._simpleTransparency.bind(this),
+    headersFinished: this._headersFinished.bind(this),
+  });
+  this._options = options;
+  this.writable = true;
+
+  this._parser.start();
+};
+util.inherits(ParserAsync, ChunkStream);
+
+export default ParserAsync;
+
+ParserAsync.prototype._handleError = function (err) {
+  this.emit("error", err);
+
+  this.writable = false;
+
+  this.destroy();
+
+  if (this._inflate && this._inflate.destroy) {
+    this._inflate.destroy();
+  }
+
+  if (this._filter) {
+    this._filter.destroy();
+    // For backward compatibility with Node 7 and below.
+    // Suppress errors due to _inflate calling write() even after
+    // it's destroy()'ed.
+    this._filter.on("error", function () {});
+  }
+
+  this.errord = true;
+};
+
+ParserAsync.prototype._inflateData = function (data) {
+  if (!this._inflate) {
+    if (this._bitmapInfo.interlace) {
+      this._inflate = zlib.createInflate();
+
+      this._inflate.on("error", this.emit.bind(this, "error"));
+      this._filter.on("complete", this._complete.bind(this));
+
+      this._inflate.pipe(this._filter);
+    } else {
+      let rowSize =
+        ((this._bitmapInfo.width *
+          this._bitmapInfo.bpp *
+          this._bitmapInfo.depth +
+          7) >>
+          3) +
+        1;
+      let imageSize = rowSize * this._bitmapInfo.height;
+      let chunkSize = Math.max(imageSize, zlib.Z_MIN_CHUNK);
+
+      this._inflate = zlib.createInflate({ chunkSize: chunkSize });
+      let leftToInflate = imageSize;
+
+      let emitError = this.emit.bind(this, "error");
+      this._inflate.on("error", function (err) {
+        if (!leftToInflate) {
+          return;
+        }
+
+        emitError(err);
+      });
+      this._filter.on("complete", this._complete.bind(this));
+
+      let filterWrite = this._filter.write.bind(this._filter);
+      this._inflate.on("data", function (chunk) {
+        if (!leftToInflate) {
+          return;
+        }
+
+        if (chunk.length > leftToInflate) {
+          chunk = chunk.slice(0, leftToInflate);
+        }
+
+        leftToInflate -= chunk.length;
+
+        filterWrite(chunk);
+      });
+
+      this._inflate.on("end", this._filter.end.bind(this._filter));
+    }
+  }
+  this._inflate.write(data);
+};
+
+ParserAsync.prototype._handleMetaData = function (metaData) {
+  this._metaData = metaData;
+  this._bitmapInfo = Object.create(metaData);
+
+  this._filter = new FilterAsync(this._bitmapInfo);
+};
+
+ParserAsync.prototype._handleTransColor = function (transColor) {
+  this._bitmapInfo.transColor = transColor;
+};
+
+ParserAsync.prototype._handlePalette = function (palette) {
+  this._bitmapInfo.palette = palette;
+};
+
+ParserAsync.prototype._simpleTransparency = function () {
+  this._metaData.alpha = true;
+};
+
+ParserAsync.prototype._headersFinished = function () {
+  // Up until this point, we don't know if we have a tRNS chunk (alpha)
+  // so we can't emit metadata any earlier
+  this.emit("metadata", this._metaData);
+};
+
+ParserAsync.prototype._finished = function () {
+  if (this.errord) {
+    return;
+  }
+
+  if (!this._inflate) {
+    this.emit("error", "No Inflate block");
+  } else {
+    // no more data to inflate
+    this._inflate.end();
+  }
+};
+
+ParserAsync.prototype._complete = function (filteredData) {
+  if (this.errord) {
+    return;
+  }
+
+  let normalisedBitmapData;
+
+  try {
+    let bitmapData = bitmapper(filteredData, this._bitmapInfo);
+
+    normalisedBitmapData = formatNormaliser(bitmapData, this._bitmapInfo);
+    bitmapData = null;
+  } catch (ex) {
+    this._handleError(ex);
+    return;
+  }
+
+  this.emit("parsed", normalisedBitmapData);
+};

lib/parser-sync.js

@@ -0,0 +1,107 @@
+import inflateSync from "./sync-inflate.js";
+import SyncReader from "./sync-reader.js";
+import FilterSync from "./filter-parse-sync.js";
+import bitmapper from "./bitmapper.js";
+import formatNormaliser from "./format-normaliser.js";
+import Parser from "./parser.js";
+
+let hasSyncZlib = true;
+let zlib = require("zlib");
+if (!zlib.deflateSync) {
+  hasSyncZlib = false;
+}
+
+export default function (buffer, options) {
+  if (!hasSyncZlib) {
+    throw new Error(
+      "To use the sync capability of this library in old node versions, please pin pngjs to v2.3.0"
+    );
+  }
+
+  let err;
+  function handleError(_err_) {
+    err = _err_;
+  }
+
+  let metaData;
+  function handleMetaData(_metaData_) {
+    metaData = _metaData_;
+  }
+
+  function handleTransColor(transColor) {
+    metaData.transColor = transColor;
+  }
+
+  function handlePalette(palette) {
+    metaData.palette = palette;
+  }
+
+  function handleSimpleTransparency() {
+    metaData.alpha = true;
+  }
+
+  let gamma;
+  function handleGamma(_gamma_) {
+    gamma = _gamma_;
+  }
+
+  let inflateDataList = [];
+  function handleInflateData(inflatedData) {
+    inflateDataList.push(inflatedData);
+  }
+
+  let reader = new SyncReader(buffer);
+
+  let parser = new Parser(options, {
+    read: reader.read.bind(reader),
+    error: handleError,
+    metadata: handleMetaData,
+    gamma: handleGamma,
+    palette: handlePalette,
+    transColor: handleTransColor,
+    inflateData: handleInflateData,
+    simpleTransparency: handleSimpleTransparency,
+  });
+
+  parser.start();
+  reader.process();
+
+  if (err) {
+    throw err;
+  }
+
+  //join together the inflate datas
+  let inflateData = Buffer.concat(inflateDataList);
+  inflateDataList.length = 0;
+
+  let inflatedData;
+  if (metaData.interlace) {
+    inflatedData = zlib.inflateSync(inflateData);
+  } else {
+    let rowSize =
+      ((metaData.width * metaData.bpp * metaData.depth + 7) >> 3) + 1;
+    let imageSize = rowSize * metaData.height;
+    inflatedData = inflateSync(inflateData, {
+      chunkSize: imageSize,
+      maxLength: imageSize,
+    });
+  }
+  inflateData = null;
+
+  if (!inflatedData || !inflatedData.length) {
+    throw new Error("bad png - invalid inflate data response");
+  }
+
+  let unfilteredData = FilterSync.process(inflatedData, metaData);
+  inflateData = null;
+
+  let bitmapData = bitmapper.dataToBitMap(unfilteredData, metaData);
+  unfilteredData = null;
+
+  let normalisedBitmapData = formatNormaliser(bitmapData, metaData);
+
+  metaData.data = normalisedBitmapData;
+  metaData.gamma = gamma || 0;
+
+  return metaData;
+};

lib/parser.js

@@ -1,359 +1,290 @@
-// Copyright (c) 2012 Kuba Niegowski
+"use strict";
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
 
-'use strict';
+let constants = require("./constants");
+let CrcCalculator = require("./crc");
 
+let Parser = (module.exports = function (options, dependencies) {
+  this._options = options;
+  options.checkCRC = options.checkCRC !== false;
 
-var util = require('util'),
+  this._hasIHDR = false;
-    zlib = require('zlib'),
+  this._hasIEND = false;
-    CrcStream = require('./crc'),
+  this._emittedHeadersFinished = false;
-    ChunkStream = require('./chunkstream'),
-    constants = require('./constants'),
-    Filter = require('./filter');
 
+  // input flags/metadata
+  this._palette = [];
+  this._colorType = 0;
 
-var Parser = module.exports = function(options) {
+  this._chunks = {};
-    ChunkStream.call(this);
+  this._chunks[constants.TYPE_IHDR] = this._handleIHDR.bind(this);
+  this._chunks[constants.TYPE_IEND] = this._handleIEND.bind(this);
+  this._chunks[constants.TYPE_IDAT] = this._handleIDAT.bind(this);
+  this._chunks[constants.TYPE_PLTE] = this._handlePLTE.bind(this);
+  this._chunks[constants.TYPE_tRNS] = this._handleTRNS.bind(this);
+  this._chunks[constants.TYPE_gAMA] = this._handleGAMA.bind(this);
 
-    this._options = options;
+  this.read = dependencies.read;
-    options.checkCRC = options.checkCRC !== false;
+  this.error = dependencies.error;
+  this.metadata = dependencies.metadata;
+  this.gamma = dependencies.gamma;
+  this.transColor = dependencies.transColor;
+  this.palette = dependencies.palette;
+  this.parsed = dependencies.parsed;
+  this.inflateData = dependencies.inflateData;
+  this.finished = dependencies.finished;
+  this.simpleTransparency = dependencies.simpleTransparency;
+  this.headersFinished = dependencies.headersFinished || function () {};
+});
 
-    this._hasIHDR = false;
+Parser.prototype.start = function () {
-    this._hasIEND = false;
+  this.read(constants.PNG_SIGNATURE.length, this._parseSignature.bind(this));
-
-    this._inflate = null;
-    this._filter = null;
-    this._crc = null;
-
-    // input flags/metadata
-    this._palette = [];
-    this._colorType = 0;
-
-    this._chunks = {};
-    this._chunks[constants.TYPE_IHDR] = this._handleIHDR.bind(this);
-    this._chunks[constants.TYPE_IEND] = this._handleIEND.bind(this);
-    this._chunks[constants.TYPE_IDAT] = this._handleIDAT.bind(this);
-    this._chunks[constants.TYPE_PLTE] = this._handlePLTE.bind(this);
-    this._chunks[constants.TYPE_tRNS] = this._handleTRNS.bind(this);
-    this._chunks[constants.TYPE_gAMA] = this._handleGAMA.bind(this);
-
-    this.writable = true;
-
-    this.on('error', this._handleError.bind(this));
-    this._handleSignature();
-};
-util.inherits(Parser, ChunkStream);
-
-
-Parser.prototype._handleError = function() {
-
-    this.writable = false;
-
-    this.destroy();
-
-    if (this._inflate)
-        this._inflate.destroy();
 };
 
-Parser.prototype._handleSignature = function() {
+Parser.prototype._parseSignature = function (data) {
-    this.read(constants.PNG_SIGNATURE.length,
+  let signature = constants.PNG_SIGNATURE;
-        this._parseSignature.bind(this)
-    );
-};
 
-Parser.prototype._parseSignature = function(data) {
+  for (let i = 0; i < signature.length; i++) {
-
+    if (data[i] !== signature[i]) {
-    var signature = constants.PNG_SIGNATURE;
+      this.error(new Error("Invalid file signature"));
-
+      return;
-    for (var i = 0; i < signature.length; i++) {
-        if (data[i] != signature[i]) {
-            this.emit('error', new Error('Invalid file signature'));
-            return;
-        }
     }
+  }
+  this.read(8, this._parseChunkBegin.bind(this));
+};
+
+Parser.prototype._parseChunkBegin = function (data) {
+  // chunk content length
+  let length = data.readUInt32BE(0);
+
+  // chunk type
+  let type = data.readUInt32BE(4);
+  let name = "";
+  for (let i = 4; i < 8; i++) {
+    name += String.fromCharCode(data[i]);
+  }
+
+  //console.log('chunk ', name, length);
+
+  // chunk flags
+  let ancillary = Boolean(data[4] & 0x20); // or critical
+  //    priv = Boolean(data[5] & 0x20), // or public
+  //    safeToCopy = Boolean(data[7] & 0x20); // or unsafe
+
+  if (!this._hasIHDR && type !== constants.TYPE_IHDR) {
+    this.error(new Error("Expected IHDR on beggining"));
+    return;
+  }
+
+  this._crc = new CrcCalculator();
+  this._crc.write(Buffer.from(name));
+
+  if (this._chunks[type]) {
+    return this._chunks[type](length);
+  }
+
+  if (!ancillary) {
+    this.error(new Error("Unsupported critical chunk type " + name));
+    return;
+  }
+
+  this.read(length + 4, this._skipChunk.bind(this));
+};
+
+Parser.prototype._skipChunk = function (/*data*/) {
+  this.read(8, this._parseChunkBegin.bind(this));
+};
+
+Parser.prototype._handleChunkEnd = function () {
+  this.read(4, this._parseChunkEnd.bind(this));
+};
+
+Parser.prototype._parseChunkEnd = function (data) {
+  let fileCrc = data.readInt32BE(0);
+  let calcCrc = this._crc.crc32();
+
+  // check CRC
+  if (this._options.checkCRC && calcCrc !== fileCrc) {
+    this.error(new Error("Crc error - " + fileCrc + " - " + calcCrc));
+    return;
+  }
+
+  if (!this._hasIEND) {
     this.read(8, this._parseChunkBegin.bind(this));
+  }
 };
 
-Parser.prototype._parseChunkBegin = function(data) {
+Parser.prototype._handleIHDR = function (length) {
+  this.read(length, this._parseIHDR.bind(this));
+};
+Parser.prototype._parseIHDR = function (data) {
+  this._crc.write(data);
 
-    // chunk content length
+  let width = data.readUInt32BE(0);
-    var length = data.readUInt32BE(0);
+  let height = data.readUInt32BE(4);
+  let depth = data[8];
+  let colorType = data[9]; // bits: 1 palette, 2 color, 4 alpha
+  let compr = data[10];
+  let filter = data[11];
+  let interlace = data[12];
 
-    // chunk type
+  // console.log('    width', width, 'height', height,
-    var type = data.readUInt32BE(4),
+  //     'depth', depth, 'colorType', colorType,
-        name = '';
+  //     'compr', compr, 'filter', filter, 'interlace', interlace
-    for (var i = 4; i < 8; i++)
+  // );
-        name += String.fromCharCode(data[i]);
 
-    // console.log('chunk ', name, length);
+  if (
+    depth !== 8 &&
+    depth !== 4 &&
+    depth !== 2 &&
+    depth !== 1 &&
+    depth !== 16
+  ) {
+    this.error(new Error("Unsupported bit depth " + depth));
+    return;
+  }
+  if (!(colorType in constants.COLORTYPE_TO_BPP_MAP)) {
+    this.error(new Error("Unsupported color type"));
+    return;
+  }
+  if (compr !== 0) {
+    this.error(new Error("Unsupported compression method"));
+    return;
+  }
+  if (filter !== 0) {
+    this.error(new Error("Unsupported filter method"));
+    return;
+  }
+  if (interlace !== 0 && interlace !== 1) {
+    this.error(new Error("Unsupported interlace method"));
+    return;
+  }
 
-    // chunk flags
+  this._colorType = colorType;
-    var ancillary  = !!(data[4] & 0x20),  // or critical
-        priv       = !!(data[5] & 0x20),  // or public
-        safeToCopy = !!(data[7] & 0x20);  // or unsafe
 
-    if (!this._hasIHDR && type != constants.TYPE_IHDR) {
+  let bpp = constants.COLORTYPE_TO_BPP_MAP[this._colorType];
-        this.emit('error', new Error('Expected IHDR on beggining'));
-        return;
-    }
 
-    this._crc = new CrcStream();
+  this._hasIHDR = true;
-    this._crc.write(new Buffer(name));
 
-    if (this._chunks[type]) {
+  this.metadata({
-        return this._chunks[type](length);
+    width: width,
+    height: height,
+    depth: depth,
+    interlace: Boolean(interlace),
+    palette: Boolean(colorType & constants.COLORTYPE_PALETTE),
+    color: Boolean(colorType & constants.COLORTYPE_COLOR),
+    alpha: Boolean(colorType & constants.COLORTYPE_ALPHA),
+    bpp: bpp,
+    colorType: colorType,
+  });
 
-    } else if (!ancillary) {
+  this._handleChunkEnd();
-        this.emit('error', new Error('Unsupported critical chunk type ' + name));
-        return;
-    } else {
-        this.read(length + 4, this._skipChunk.bind(this));
-    }
 };
 
-Parser.prototype._skipChunk = function(data) {
+Parser.prototype._handlePLTE = function (length) {
-    this.read(8, this._parseChunkBegin.bind(this));
+  this.read(length, this._parsePLTE.bind(this));
+};
+Parser.prototype._parsePLTE = function (data) {
+  this._crc.write(data);
+
+  let entries = Math.floor(data.length / 3);
+  // console.log('Palette:', entries);
+
+  for (let i = 0; i < entries; i++) {
+    this._palette.push([data[i * 3], data[i * 3 + 1], data[i * 3 + 2], 0xff]);
+  }
+
+  this.palette(this._palette);
+
+  this._handleChunkEnd();
 };
 
-Parser.prototype._handleChunkEnd = function() {
+Parser.prototype._handleTRNS = function (length) {
-    this.read(4, this._parseChunkEnd.bind(this));
+  this.simpleTransparency();
+  this.read(length, this._parseTRNS.bind(this));
+};
+Parser.prototype._parseTRNS = function (data) {
+  this._crc.write(data);
+
+  // palette
+  if (this._colorType === constants.COLORTYPE_PALETTE_COLOR) {
+    if (this._palette.length === 0) {
+      this.error(new Error("Transparency chunk must be after palette"));
+      return;
+    }
+    if (data.length > this._palette.length) {
+      this.error(new Error("More transparent colors than palette size"));
+      return;
+    }
+    for (let i = 0; i < data.length; i++) {
+      this._palette[i][3] = data[i];
+    }
+    this.palette(this._palette);
+  }
+
+  // for colorType 0 (grayscale) and 2 (rgb)
+  // there might be one gray/color defined as transparent
+  if (this._colorType === constants.COLORTYPE_GRAYSCALE) {
+    // grey, 2 bytes
+    this.transColor([data.readUInt16BE(0)]);
+  }
+  if (this._colorType === constants.COLORTYPE_COLOR) {
+    this.transColor([
+      data.readUInt16BE(0),
+      data.readUInt16BE(2),
+      data.readUInt16BE(4),
+    ]);
+  }
+
+  this._handleChunkEnd();
 };
 
-Parser.prototype._parseChunkEnd = function(data) {
+Parser.prototype._handleGAMA = function (length) {
+  this.read(length, this._parseGAMA.bind(this));
+};
+Parser.prototype._parseGAMA = function (data) {
+  this._crc.write(data);
+  this.gamma(data.readUInt32BE(0) / constants.GAMMA_DIVISION);
 
-    var fileCrc = data.readInt32BE(0),
+  this._handleChunkEnd();
-        calcCrc = this._crc.crc32();
-
-    // check CRC
-    if (this._options.checkCRC && calcCrc != fileCrc) {
-        this.emit('error', new Error('Crc error'));
-        return;
-    }
-
-    if (this._hasIEND) {
-        this.destroySoon();
-
-    } else {
-        this.read(8, this._parseChunkBegin.bind(this));
-    }
 };
 
-
+Parser.prototype._handleIDAT = function (length) {
-Parser.prototype._handleIHDR = function(length) {
+  if (!this._emittedHeadersFinished) {
-    this.read(length, this._parseIHDR.bind(this));
+    this._emittedHeadersFinished = true;
+    this.headersFinished();
+  }
+  this.read(-length, this._parseIDAT.bind(this, length));
 };
-Parser.prototype._parseIHDR = function(data) {
+Parser.prototype._parseIDAT = function (length, data) {
+  this._crc.write(data);
 
-    this._crc.write(data);
+  if (
+    this._colorType === constants.COLORTYPE_PALETTE_COLOR &&
+    this._palette.length === 0
+  ) {
+    throw new Error("Expected palette not found");
+  }
 
-    var width = data.readUInt32BE(0),
+  this.inflateData(data);
-        height = data.readUInt32BE(4),
+  let leftOverLength = length - data.length;
-        depth = data[8],
-        colorType = data[9], // bits: 1 palette, 2 color, 4 alpha
-        compr = data[10],
-        filter = data[11],
-        interlace = data[12];
-
-    // console.log('    width', width, 'height', height,
-    //     'depth', depth, 'colorType', colorType,
-    //     'compr', compr, 'filter', filter, 'interlace', interlace
-    // );
-
-    if (depth != 8) {
-        this.emit('error', new Error('Unsupported bit depth ' + depth));
-        return;
-    }
-    if (!(colorType in colorTypeToBppMap)) {
-        this.emit('error', new Error('Unsupported color type'));
-        return;
-    }
-    if (compr != 0) {
-        this.emit('error', new Error('Unsupported compression method'));
-        return;
-    }
-    if (filter != 0) {
-        this.emit('error', new Error('Unsupported filter method'));
-        return;
-    }
-    if (interlace != 0) {
-        this.emit('error', new Error('Unsupported interlace method'));
-        return;
-    }
-
-    this._colorType = colorType;
-
-    this._data = new Buffer(width * height * 4);
-    this._filter = new Filter(
-        width, height,
-        colorTypeToBppMap[this._colorType],
-        this._data,
-        this._options
-    );
-
-    this._hasIHDR = true;
-
-    this.emit('metadata', {
-        width: width,
-        height: height,
-        palette: !!(colorType & constants.COLOR_PALETTE),
-        color: !!(colorType & constants.COLOR_COLOR),
-        alpha: !!(colorType & constants.COLOR_ALPHA),
-        data: this._data
-    });
 
+  if (leftOverLength > 0) {
+    this._handleIDAT(leftOverLength);
+  } else {
     this._handleChunkEnd();
+  }
 };
 
-
+Parser.prototype._handleIEND = function (length) {
-Parser.prototype._handlePLTE = function(length) {
+  this.read(length, this._parseIEND.bind(this));
-    this.read(length, this._parsePLTE.bind(this));
 };
-Parser.prototype._parsePLTE = function(data) {
+Parser.prototype._parseIEND = function (data) {
+  this._crc.write(data);
 
-    this._crc.write(data);
+  this._hasIEND = true;
+  this._handleChunkEnd();
 
-    var entries = Math.floor(data.length / 3);
+  if (this.finished) {
-    // console.log('Palette:', entries);
+    this.finished();
-
+  }
-    for (var i = 0; i < entries; i++) {
-        this._palette.push([
-            data.readUInt8(i * 3),
-            data.readUInt8(i * 3 + 1),
-            data.readUInt8(i * 3 + 2 ),
-            0xff
-        ]);
-    }
-
-    this._handleChunkEnd();
-};
-
-Parser.prototype._handleTRNS = function(length) {
-    this.read(length, this._parseTRNS.bind(this));
-};
-Parser.prototype._parseTRNS = function(data) {
-
-    this._crc.write(data);
-
-    // palette
-    if (this._colorType == 3) {
-        if (this._palette.length == 0) {
-            this.emit('error', new Error('Transparency chunk must be after palette'));
-            return;
-        }
-        if (data.length > this._palette.length) {
-            this.emit('error', new Error('More transparent colors than palette size'));
-            return;
-        }
-        for (var i = 0; i < this._palette.length; i++) {
-            this._palette[i][3] = i < data.length ? data.readUInt8(i) : 0xff;
-        }
-    }
-
-    // for colorType 0 (grayscale) and 2 (rgb)
-    // there might be one gray/color defined as transparent
-
-    this._handleChunkEnd();
-};
-
-Parser.prototype._handleGAMA = function(length) {
-    this.read(length, this._parseGAMA.bind(this));
-};
-Parser.prototype._parseGAMA = function(data) {
-
-    this._crc.write(data);
-    this.emit('gamma', data.readUInt32BE(0) / 100000);
-
-    this._handleChunkEnd();
-};
-
-Parser.prototype._handleIDAT = function(length) {
-    this.read(-length, this._parseIDAT.bind(this, length));
-};
-Parser.prototype._parseIDAT = function(length, data) {
-
-    this._crc.write(data);
-
-    if (this._colorType == 3 && this._palette.length == 0)
-        throw new Error('Expected palette not found');
-
-    if (!this._inflate) {
-        this._inflate = zlib.createInflate();
-
-        this._inflate.on('error', this.emit.bind(this, 'error'));
-        this._filter.on('complete', this._reverseFiltered.bind(this));
-
-        this._inflate.pipe(this._filter);
-    }
-
-    this._inflate.write(data);
-    length -= data.length;
-
-    if (length > 0)
-        this._handleIDAT(length);
-    else
-        this._handleChunkEnd();
-};
-
-
-Parser.prototype._handleIEND = function(length) {
-    this.read(length, this._parseIEND.bind(this));
-};
-Parser.prototype._parseIEND = function(data) {
-
-    this._crc.write(data);
-
-    // no more data to inflate
-    this._inflate.end();
-
-    this._hasIEND = true;
-    this._handleChunkEnd();
-};
-
-
-var colorTypeToBppMap = {
-    0: 1,
-    2: 3,
-    3: 1,
-    4: 2,
-    6: 4
-};
-
-Parser.prototype._reverseFiltered = function(data, width, height) {
-
-    if (this._colorType == 3) { // paletted
-
-        // use values from palette
-        var pxLineLength = width << 2;
-
-        for (var y = 0; y < height; y++) {
-            var pxRowPos = y * pxLineLength;
-
-            for (var x = 0; x < width; x++) {
-                var pxPos = pxRowPos + (x << 2),
-                    color = this._palette[data[pxPos]];
-
-                for (var i = 0; i < 4; i++)
-                    data[pxPos + i] = color[i];
-            }
-        }
-    }
-
-    this.emit('parsed', data);
 };

lib/png-sync.js

@@ -0,0 +1,15 @@
+import parse from "./parser-sync.js";
+import pack from "./packer-sync.js";
+
+export var read = function (buffer, options) {
+  return parse(buffer, options || {});
+};
+
+export var write = function (png, options) {
+  return pack(png, options);
+};
+
+export default {
+  read,
+  write
+}

lib/png.js

@@ -1,149 +1,193 @@
-// Copyright (c) 2012 Kuba Niegowski
+import Parser from "./parser-async.js";
-//
+import Packer from "./packer-async.js";
-// Permission is hereby granted, free of charge, to any person obtaining a copy
+import PNGSync from "./png-sync.js";
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
 
-'use strict';
+let util = require("util");
+let Stream = require("stream");
 
+let PNG = (exports.PNG = function (options) {
+  Stream.call(this);
 
-var util = require('util'),
+  options = options || {}; // eslint-disable-line no-param-reassign
-    Stream = require('stream'),
-    Parser = require('./parser'),
-    Packer = require('./packer');
 
+  // coerce pixel dimensions to integers (also coerces undefined -> 0):
+  this.width = options.width | 0;
+  this.height = options.height | 0;
 
-var PNG = exports.PNG = function(options) {
+  this.data =
-    Stream.call(this);
+    this.width > 0 && this.height > 0
+      ? Buffer.alloc(4 * this.width * this.height)
+      : null;
 
-    options = options || {};
+  if (options.fill && this.data) {
+    this.data.fill(0);
+  }
 
-    this.width = options.width || 0;
+  this.gamma = 0;
-    this.height = options.height || 0;
+  this.readable = this.writable = true;
-		
-    this.data = this.width > 0 && this.height > 0
-            ? new Buffer(4 * this.width * this.height) : null;
 
-	  if(options.fill && this.data){this.data.fill(0)};
+  this._parser = new Parser(options);
 
-    this.gamma = 0;
+  this._parser.on("error", this.emit.bind(this, "error"));
-    this.readable = this.writable = true;
+  this._parser.on("close", this._handleClose.bind(this));
+  this._parser.on("metadata", this._metadata.bind(this));
+  this._parser.on("gamma", this._gamma.bind(this));
+  this._parser.on(
+    "parsed",
+    function (data) {
+      this.data = data;
+      this.emit("parsed", data);
+    }.bind(this)
+  );
 
-    this._parser = new Parser(options || {});
+  this._packer = new Packer(options);
-
+  this._packer.on("data", this.emit.bind(this, "data"));
-    this._parser.on('error', this.emit.bind(this, 'error'));
+  this._packer.on("end", this.emit.bind(this, "end"));
-    this._parser.on('close', this._handleClose.bind(this));
+  this._parser.on("close", this._handleClose.bind(this));
-    this._parser.on('metadata', this._metadata.bind(this));
+  this._packer.on("error", this.emit.bind(this, "error"));
-    this._parser.on('gamma', this._gamma.bind(this));
+});
-    this._parser.on('parsed', function(data) {
-        this.data = data;
-        this.emit('parsed', data);
-    }.bind(this));
-
-    this._packer = new Packer(options);
-    this._packer.on('data', this.emit.bind(this, 'data'));
-    this._packer.on('end', this.emit.bind(this, 'end'));
-    this._parser.on('close', this._handleClose.bind(this));
-    this._packer.on('error', this.emit.bind(this, 'error'));
-
-};
 util.inherits(PNG, Stream);
 
+PNG.sync = PNGSync;
 
-PNG.prototype.pack = function() {
+PNG.prototype.pack = function () {
-
+  if (!this.data || !this.data.length) {
-    process.nextTick(function() {
+    this.emit("error", "No data provided");
-        this._packer.pack(this.data, this.width, this.height);
-    }.bind(this));
-
     return this;
+  }
+
+  process.nextTick(
+    function () {
+      this._packer.pack(this.data, this.width, this.height, this.gamma);
+    }.bind(this)
+  );
+
+  return this;
 };
 
+PNG.prototype.parse = function (data, callback) {
+  if (callback) {
+    let onParsed, onError;
 
-PNG.prototype.parse = function(data, callback) {
+    onParsed = function (parsedData) {
+      this.removeListener("error", onError);
 
-    if (callback) {
+      this.data = parsedData;
-        var onParsed = null, onError = null;
+      callback(null, this);
+    }.bind(this);
 
-        this.once('parsed', onParsed = function(data) {
+    onError = function (err) {
-            this.removeListener('error', onError);
+      this.removeListener("parsed", onParsed);
 
-            this.data = data;
+      callback(err, null);
-            callback(null, this);
+    }.bind(this);
 
-        }.bind(this));
+    this.once("parsed", onParsed);
+    this.once("error", onError);
+  }
 
-        this.once('error', onError = function(err) {
+  this.end(data);
-            this.removeListener('parsed', onParsed);
+  return this;
+};
 
-            callback(err, null);
+PNG.prototype.write = function (data) {
-        }.bind(this));
+  this._parser.write(data);
+  return true;
+};
+
+PNG.prototype.end = function (data) {
+  this._parser.end(data);
+};
+
+PNG.prototype._metadata = function (metadata) {
+  this.width = metadata.width;
+  this.height = metadata.height;
+
+  this.emit("metadata", metadata);
+};
+
+PNG.prototype._gamma = function (gamma) {
+  this.gamma = gamma;
+};
+
+PNG.prototype._handleClose = function () {
+  if (!this._parser.writable && !this._packer.readable) {
+    this.emit("close");
+  }
+};
+
+PNG.bitblt = function (src, dst, srcX, srcY, width, height, deltaX, deltaY) {
+  // eslint-disable-line max-params
+  // coerce pixel dimensions to integers (also coerces undefined -> 0):
+  /* eslint-disable no-param-reassign */
+  srcX |= 0;
+  srcY |= 0;
+  width |= 0;
+  height |= 0;
+  deltaX |= 0;
+  deltaY |= 0;
+  /* eslint-enable no-param-reassign */
+
+  if (
+    srcX > src.width ||
+    srcY > src.height ||
+    srcX + width > src.width ||
+    srcY + height > src.height
+  ) {
+    throw new Error("bitblt reading outside image");
+  }
+
+  if (
+    deltaX > dst.width ||
+    deltaY > dst.height ||
+    deltaX + width > dst.width ||
+    deltaY + height > dst.height
+  ) {
+    throw new Error("bitblt writing outside image");
+  }
+
+  for (let y = 0; y < height; y++) {
+    src.data.copy(
+      dst.data,
+      ((deltaY + y) * dst.width + deltaX) << 2,
+      ((srcY + y) * src.width + srcX) << 2,
+      ((srcY + y) * src.width + srcX + width) << 2
+    );
+  }
+};
+
+PNG.prototype.bitblt = function (
+  dst,
+  srcX,
+  srcY,
+  width,
+  height,
+  deltaX,
+  deltaY
+) {
+  // eslint-disable-line max-params
+
+  PNG.bitblt(this, dst, srcX, srcY, width, height, deltaX, deltaY);
+  return this;
+};
+
+PNG.adjustGamma = function (src) {
+  if (src.gamma) {
+    for (let y = 0; y < src.height; y++) {
+      for (let x = 0; x < src.width; x++) {
+        let idx = (src.width * y + x) << 2;
+
+        for (let i = 0; i < 3; i++) {
+          let sample = src.data[idx + i] / 255;
+          sample = Math.pow(sample, 1 / 2.2 / src.gamma);
+          src.data[idx + i] = Math.round(sample * 255);
+        }
+      }
     }
-
+    src.gamma = 0;
-    this.end(data);
+  }
-    return this;
 };
 
-PNG.prototype.write = function(data) {
+PNG.prototype.adjustGamma = function () {
-    this._parser.write(data);
+  PNG.adjustGamma(this);
-    return true;
-};
-
-PNG.prototype.end = function(data) {
-    this._parser.end(data);
-};
-
-PNG.prototype._metadata = function(metadata) {
-    this.width = metadata.width;
-    this.height = metadata.height;
-    this.data = metadata.data;
-
-    delete metadata.data;
-    this.emit('metadata', metadata);
-};
-
-PNG.prototype._gamma = function(gamma) {
-    this.gamma = gamma;
-};
-
-PNG.prototype._handleClose = function() {
-    if (!this._parser.writable && !this._packer.readable)
-        this.emit('close');
-};
-
-
-PNG.prototype.bitblt = function(dst, sx, sy, w, h, dx, dy) {
-
-    var src = this;
-
-    if (sx > src.width || sy > src.height
-            || sx + w > src.width || sy + h > src.height)
-        throw new Error('bitblt reading outside image');
-    if (dx > dst.width || dy > dst.height
-            || dx + w > dst.width || dy + h > dst.height)
-        throw new Error('bitblt writing outside image');
-
-    for (var y = 0; y < h; y++) {
-        src.data.copy(dst.data,
-            ((dy + y) * dst.width + dx) << 2,
-            ((sy + y) * src.width + sx) << 2,
-            ((sy + y) * src.width + sx + w) << 2
-        );
-    }
-
-    return this;
 };

lib/sync-inflate.js

@@ -0,0 +1,163 @@
+let assert = require("assert").ok;
+let zlib = require("zlib");
+let util = require("util");
+
+let kMaxLength = require("buffer").kMaxLength;
+
+export function Inflate(opts) {
+  if (!(this instanceof Inflate)) {
+    return new Inflate(opts);
+  }
+
+  if (opts && opts.chunkSize < zlib.Z_MIN_CHUNK) {
+    opts.chunkSize = zlib.Z_MIN_CHUNK;
+  }
+
+  zlib.Inflate.call(this, opts);
+
+  // Node 8 --> 9 compatibility check
+  this._offset = this._offset === undefined ? this._outOffset : this._offset;
+  this._buffer = this._buffer || this._outBuffer;
+
+  if (opts && opts.maxLength != null) {
+    this._maxLength = opts.maxLength;
+  }
+}
+
+export function createInflate(opts) {
+  return new Inflate(opts);
+}
+
+function _close(engine, callback) {
+  if (callback) {
+    process.nextTick(callback);
+  }
+
+  // Caller may invoke .close after a zlib error (which will null _handle).
+  if (!engine._handle) {
+    return;
+  }
+
+  engine._handle.close();
+  engine._handle = null;
+}
+
+Inflate.prototype._processChunk = function (chunk, flushFlag, asyncCb) {
+  if (typeof asyncCb === "function") {
+    return zlib.Inflate._processChunk.call(this, chunk, flushFlag, asyncCb);
+  }
+
+  let self = this;
+
+  let availInBefore = chunk && chunk.length;
+  let availOutBefore = this._chunkSize - this._offset;
+  let leftToInflate = this._maxLength;
+  let inOff = 0;
+
+  let buffers = [];
+  let nread = 0;
+
+  let error;
+  this.on("error", function (err) {
+    error = err;
+  });
+
+  function handleChunk(availInAfter, availOutAfter) {
+    if (self._hadError) {
+      return;
+    }
+
+    let have = availOutBefore - availOutAfter;
+    assert(have >= 0, "have should not go down");
+
+    if (have > 0) {
+      let out = self._buffer.slice(self._offset, self._offset + have);
+      self._offset += have;
+
+      if (out.length > leftToInflate) {
+        out = out.slice(0, leftToInflate);
+      }
+
+      buffers.push(out);
+      nread += out.length;
+      leftToInflate -= out.length;
+
+      if (leftToInflate === 0) {
+        return false;
+      }
+    }
+
+    if (availOutAfter === 0 || self._offset >= self._chunkSize) {
+      availOutBefore = self._chunkSize;
+      self._offset = 0;
+      self._buffer = Buffer.allocUnsafe(self._chunkSize);
+    }
+
+    if (availOutAfter === 0) {
+      inOff += availInBefore - availInAfter;
+      availInBefore = availInAfter;
+
+      return true;
+    }
+
+    return false;
+  }
+
+  assert(this._handle, "zlib binding closed");
+  let res;
+  do {
+    res = this._handle.writeSync(
+      flushFlag,
+      chunk, // in
+      inOff, // in_off
+      availInBefore, // in_len
+      this._buffer, // out
+      this._offset, //out_off
+      availOutBefore
+    ); // out_len
+    // Node 8 --> 9 compatibility check
+    res = res || this._writeState;
+  } while (!this._hadError && handleChunk(res[0], res[1]));
+
+  if (this._hadError) {
+    throw error;
+  }
+
+  if (nread >= kMaxLength) {
+    _close(this);
+    throw new RangeError(
+      "Cannot create final Buffer. It would be larger than 0x" +
+        kMaxLength.toString(16) +
+        " bytes"
+    );
+  }
+
+  let buf = Buffer.concat(buffers, nread);
+  _close(this);
+
+  return buf;
+};
+
+util.inherits(Inflate, zlib.Inflate);
+
+function zlibBufferSync(engine, buffer) {
+  if (typeof buffer === "string") {
+    buffer = Buffer.from(buffer);
+  }
+  if (!(buffer instanceof Buffer)) {
+    throw new TypeError("Not a string or buffer");
+  }
+
+  let flushFlag = engine._finishFlushFlag;
+  if (flushFlag == null) {
+    flushFlag = zlib.Z_FINISH;
+  }
+
+  return engine._processChunk(buffer, flushFlag);
+}
+
+export function inflateSync(buffer, opts) {
+  return zlibBufferSync(new Inflate(opts), buffer);
+}
+
+export default inflateSync;

lib/sync-reader.js

@@ -0,0 +1,45 @@
+let SyncReader = function (buffer) {
+  this._buffer = buffer;
+  this._reads = [];
+};
+
+export default SyncReader;
+
+SyncReader.prototype.read = function (length, callback) {
+  this._reads.push({
+    length: Math.abs(length), // if length < 0 then at most this length
+    allowLess: length < 0,
+    func: callback,
+  });
+};
+
+SyncReader.prototype.process = function () {
+  // as long as there is any data and read requests
+  while (this._reads.length > 0 && this._buffer.length) {
+    let read = this._reads[0];
+
+    if (
+      this._buffer.length &&
+      (this._buffer.length >= read.length || read.allowLess)
+    ) {
+      // ok there is any data so that we can satisfy this request
+      this._reads.shift(); // == read
+
+      let buf = this._buffer;
+
+      this._buffer = buf.slice(read.length);
+
+      read.func.call(this, buf.slice(0, read.length));
+    } else {
+      break;
+    }
+  }
+
+  if (this._reads.length > 0) {
+    return new Error("There are some read requests waitng on finished stream");
+  }
+
+  if (this._buffer.length > 0) {
+    return new Error("unrecognised content at end of stream");
+  }
+};

package.json

@@ -1,29 +1,73 @@
 {
-  "name": "node-png",
+  "name": "pngjs",
-  "version": "0.4.3",
+  "version": "5.0.0",
-  "description": "Simple PNG encoder/decoder",
+  "description": "PNG encoder/decoder in pure JS, supporting any bit size & interlace, async & sync with full test suite.",
-  "author": "Kuba Niegowski",
+  "contributors": [
-  "contributors": [],
+    "Alexandre Paré",
-  "homepage": "https://github.com/niegowski/node-pngjs/",
+    "Gaurav Mali",
+    "Gusts Kaksis",
+    "Kuba Niegowski",
+    "Luke Page",
+    "Pietajan De Potter",
+    "Steven Sojka",
+    "liangzeng",
+    "Michael Vogt",
+    "Xin-Xin Wang",
+    "toriningen",
+    "Eugene Kulabuhov"
+  ],
+  "homepage": "https://github.com/lukeapage/pngjs",
   "keywords": [
-    "png"
+    "PNG",
+    "decoder",
+    "encoder",
+    "js-png",
+    "node-png",
+    "parser",
+    "png",
+    "png-js",
+    "png-parse",
+    "pngjs"
   ],
   "engines": {
-    "node": "0.8.x"
+    "node": ">=10.13.0"
   },
   "main": "./lib/png.js",
   "directories": {
-    "example": "examples"
+    "lib": "lib",
+    "example": "examples",
+    "test": "test"
   },
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "build": "yarn prepublish",
+    "prepublish": "yarn browserify",
+    "browserify": "browserify lib/png.js --standalone png > browser.js",
+    "coverage": "nyc --reporter=lcov --reporter=text-summary tape test/*-spec.js nolarge",
+    "test": "yarn lint && yarn prettier:check && tape test/*-spec.js | tap-dot && node test/run-compare",
+    "lint": "eslint .",
+    "prettier:write": "prettier --write .",
+    "prettier:check": "prettier --check ."
   },
   "repository": {
     "type": "git",
-    "url": "git://github.com/brighthas/node-pngjs.git"
+    "url": "git://github.com/lukeapage/pngjs.git"
   },
   "license": "MIT",
   "bugs": {
-    "url": "https://github.com/brighthas/node-pngjs/issues"
+    "url": "https://github.com/lukeapage/pngjs/issues"
+  },
+  "devDependencies": {
+    "browserify": "16.5.1",
+    "buffer-equal": "1.0.0",
+    "codecov": "3.7.0",
+    "connect": "3.7.0",
+    "eslint": "7.0.0",
+    "eslint-config-prettier": "6.11.0",
+    "nyc": "15.0.1",
+    "prettier": "2.0.5",
+    "puppeteer": "3.0.2",
+    "serve-static": "1.14.1",
+    "tap-dot": "2.0.0",
+    "tape": "5.0.0"
   }
 }

test/.gitignore

@@ -0,0 +1 @@
+bg.png

test/bg-spec.js

@@ -0,0 +1,46 @@
+#!/usr/bin/env node
+
+let fs = require("fs");
+let PNG = require("../lib/png").PNG;
+let test = require("tape");
+let bufferEqual = require("buffer-equal");
+
+test("outputs background, created from scratch", function (t) {
+  t.timeoutAfter(1000 * 60 * 5);
+
+  let png = new PNG({
+    width: 10,
+    height: 10,
+    filterType: -1,
+  });
+
+  for (let y = 0; y < png.height; y++) {
+    for (let x = 0; x < png.width; x++) {
+      let idx = (png.width * y + x) << 2;
+
+      let col = (x < png.width >> 1) ^ (y < png.height >> 1) ? 0xe5 : 0xff;
+
+      png.data[idx] = col;
+      png.data[idx + 1] = col;
+      png.data[idx + 2] = col;
+      png.data[idx + 3] = 0xff;
+    }
+  }
+
+  png
+    .pack()
+    .pipe(fs.createWriteStream(__dirname + "/bg.png"))
+    .on("finish", function () {
+      let out = fs.readFileSync(__dirname + "/bg.png");
+      let ref = fs.readFileSync(__dirname + "/bg-ref.png");
+
+      let isBufferEqual = bufferEqual(out, ref);
+      t.ok(isBufferEqual, "compares with working file ok");
+
+      if (!isBufferEqual) {
+        console.log(out.length, ref.length);
+      }
+
+      t.end();
+    });
+});

test/convert-images-spec.js

@@ -0,0 +1,105 @@
+let fs = require("fs");
+let PNG = require("../lib/png").PNG;
+let test = require("tape");
+
+let noLargeOption = process.argv.indexOf("nolarge") >= 0;
+
+fs.readdir(__dirname + "/in/", function (err, files) {
+  if (err) throw err;
+
+  files = files.filter(function (file) {
+    return (
+      (!noLargeOption || !file.match(/large/i)) &&
+      Boolean(file.match(/\.png$/i))
+    );
+  });
+
+  console.log("Converting images");
+
+  files.forEach(function (file) {
+    let expectedError = false;
+    if (file.match(/^x/)) {
+      expectedError = true;
+    }
+
+    test("convert sync - " + file, function (t) {
+      t.timeoutAfter(1000 * 60 * 5);
+
+      let data = fs.readFileSync(__dirname + "/in/" + file);
+      let png;
+      try {
+        png = PNG.sync.read(data);
+      } catch (e) {
+        if (!expectedError) {
+          t.fail(
+            "Unexpected error parsing.." +
+              file +
+              "\n" +
+              e.message +
+              "\n" +
+              e.stack
+          );
+        } else {
+          t.pass("completed");
+        }
+        return t.end();
+      }
+
+      if (expectedError) {
+        t.fail("Sync: Error expected, parsed fine .. - " + file);
+        return t.end();
+      }
+
+      let outpng = new PNG();
+      outpng.gamma = png.gamma;
+      outpng.data = png.data;
+      outpng.width = png.width;
+      outpng.height = png.height;
+      outpng.pack().pipe(
+        fs
+          .createWriteStream(__dirname + "/outsync/" + file)
+          .on("finish", function () {
+            t.pass("completed");
+            t.end();
+          })
+      );
+    });
+
+    test("convert async - " + file, function (t) {
+      t.timeoutAfter(1000 * 60 * 5);
+
+      fs.createReadStream(__dirname + "/in/" + file)
+        .pipe(new PNG())
+        .on("error", function (err) {
+          if (!expectedError) {
+            t.fail(
+              "Async: Unexpected error parsing.." +
+                file +
+                "\n" +
+                err.message +
+                "\n" +
+                err.stack
+            );
+          } else {
+            t.pass("completed");
+          }
+          t.end();
+        })
+        .on("parsed", function () {
+          if (expectedError) {
+            t.fail("Async: Error expected, parsed fine .." + file);
+            return t.end();
+          }
+
+          this.pack().pipe(
+            fs
+              .createWriteStream(__dirname + "/out/" + file)
+              .on("finish", function () {
+                t.pass("completed");
+                t.end();
+              })
+          );
+        });
+    });
+  });
+});

test/http-server.js

@@ -0,0 +1,16 @@
+let serveStatic = require("serve-static");
+let http = require("http");
+let connect = require("connect");
+
+let app = connect();
+let server = http.createServer(app);
+
+app.use(serveStatic("test"));
+
+server.listen(8000);
+
+module.exports = () => {
+  server.close();
+};
+
+console.log("Tests available at http://localhost:8000/");

test/imagediff.js

@@ -0,0 +1,409 @@
+// js-imagediff 1.0.3
+// (c) 2011-2012 Carl Sutherland, Humble Software
+// Distributed under the MIT License
+// For original source and documentation visit:
+// http://www.github.com/HumbleSoftware/js-imagediff
+
+(function (name, definition) {
+  var root = this;
+  if (typeof module !== 'undefined') {
+    try {
+      var Canvas = require('canvas');
+    } catch (e) {
+      throw new Error(
+        e.message + '\n' +
+        'Please see https://github.com/HumbleSoftware/js-imagediff#cannot-find-module-canvas\n'
+      );
+    }
+    module.exports = definition(root, name, Canvas);
+  } else if (typeof define === 'function' && typeof define.amd === 'object') {
+    define(definition);
+  } else {
+    root[name] = definition(root, name);
+  }
+})('imagediff', function (root, name, Canvas) {
+
+  var
+    TYPE_ARRAY        = /\[object Array\]/i,
+    TYPE_CANVAS       = /\[object (Canvas|HTMLCanvasElement)\]/i,
+    TYPE_CONTEXT      = /\[object CanvasRenderingContext2D\]/i,
+    TYPE_IMAGE        = /\[object (Image|HTMLImageElement)\]/i,
+    TYPE_IMAGE_DATA   = /\[object ImageData\]/i,
+
+    UNDEFINED         = 'undefined',
+
+    canvas            = getCanvas(),
+    context           = canvas.getContext('2d'),
+    previous          = root[name],
+    imagediff, jasmine;
+
+  // Creation
+  function getCanvas (width, height) {
+    var
+      canvas = Canvas ?
+        new Canvas() :
+        document.createElement('canvas');
+    if (width) canvas.width = width;
+    if (height) canvas.height = height;
+    return canvas;
+  }
+  function getImageData (width, height) {
+    canvas.width = width;
+    canvas.height = height;
+    context.clearRect(0, 0, width, height);
+    return context.createImageData(width, height);
+  }
+  // expost canvas module
+  function getCanvasRef() {
+    return Canvas;
+  }
+
+
+  // Type Checking
+  function isImage (object) {
+    return isType(object, TYPE_IMAGE);
+  }
+  function isCanvas (object) {
+    return isType(object, TYPE_CANVAS);
+  }
+  function isContext (object) {
+    return isType(object, TYPE_CONTEXT);
+  }
+  function isImageData (object) {
+    return !!(object &&
+      isType(object, TYPE_IMAGE_DATA) &&
+      typeof(object.width) !== UNDEFINED &&
+      typeof(object.height) !== UNDEFINED &&
+      typeof(object.data) !== UNDEFINED);
+  }
+  function isImageType (object) {
+    return (
+      isImage(object) ||
+      isCanvas(object) ||
+      isContext(object) ||
+      isImageData(object)
+    );
+  }
+  function isType (object, type) {
+    return typeof (object) === 'object' && !!Object.prototype.toString.apply(object).match(type);
+  }
+
+
+  // Type Conversion
+  function copyImageData (imageData) {
+    var
+      height = imageData.height,
+      width = imageData.width,
+      data = imageData.data,
+      newImageData, newData, i;
+
+    canvas.width = width;
+    canvas.height = height;
+    newImageData = context.getImageData(0, 0, width, height);
+    newData = newImageData.data;
+
+    for (i = imageData.data.length; i--;) {
+        newData[i] = data[i];
+    }
+
+    return newImageData;
+  }
+  function toImageData (object) {
+    if (isImage(object)) { return toImageDataFromImage(object); }
+    if (isCanvas(object)) { return toImageDataFromCanvas(object); }
+    if (isContext(object)) { return toImageDataFromContext(object); }
+    if (isImageData(object)) { return object; }
+  }
+  function toImageDataFromImage (image) {
+    var
+      height = image.height,
+      width = image.width;
+    canvas.width = width;
+    canvas.height = height;
+    context.clearRect(0, 0, width, height);
+    context.drawImage(image, 0, 0);
+    return context.getImageData(0, 0, width, height);
+  }
+  function toImageDataFromCanvas (canvas) {
+    var
+      height = canvas.height,
+      width = canvas.width,
+      context = canvas.getContext('2d');
+    return context.getImageData(0, 0, width, height);
+  }
+  function toImageDataFromContext (context) {
+    var
+      canvas = context.canvas,
+      height = canvas.height,
+      width = canvas.width;
+    return context.getImageData(0, 0, width, height);
+  }
+  function toCanvas (object) {
+    var
+      data = toImageData(object),
+      canvas = getCanvas(data.width, data.height),
+      context = canvas.getContext('2d');
+
+    context.putImageData(data, 0, 0);
+    return canvas;
+  }
+
+
+  // ImageData Equality Operators
+  function equalWidth (a, b) {
+    return a.width === b.width;
+  }
+  function equalHeight (a, b) {
+    return a.height === b.height;
+  }
+  function equalDimensions (a, b) {
+    return equalHeight(a, b) && equalWidth(a, b);
+  }
+  function equal (a, b, tolerance) {
+
+    var
+      aData     = a.data,
+      bData     = b.data,
+      length    = aData.length,
+      i;
+
+    tolerance = tolerance || 0;
+
+    if (!equalDimensions(a, b)) return false;
+    for (i = length; i--;) {
+      if (aData[i] !== bData[i] && Math.abs(aData[i] - bData[i]) > tolerance) {
+        var x = i % (a.width * 4);
+        var y = (i - x) / (a.width * 4);
+        var color = x % 4;
+        x = (x - color) / 4;
+        console.log("Difference x", x, "y", y, ["R", "G", "B", "A"][color], "  -  ", aData[i], " !== ", bData[i]);
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+
+  // Diff
+  function diff (a, b, options) {
+    return (equalDimensions(a, b) ? diffEqual : diffUnequal)(a, b, options);
+  }
+  function diffEqual (a, b, options) {
+
+    var
+      height  = a.height,
+      width   = a.width,
+      c       = getImageData(width, height), // c = a - b
+      aData   = a.data,
+      bData   = b.data,
+      cData   = c.data,
+      length  = cData.length,
+      row, column,
+      i, j, k, v;
+
+    for (i = 0; i < length; i += 4) {
+      cData[i] = Math.abs(aData[i] - bData[i]);
+      cData[i+1] = Math.abs(aData[i+1] - bData[i+1]);
+      cData[i+2] = Math.abs(aData[i+2] - bData[i+2]);
+      cData[i+3] = Math.abs(255 - Math.abs(aData[i+3] - bData[i+3]));
+    }
+
+    return c;
+  }
+  function diffUnequal (a, b, options) {
+
+    var
+      height  = Math.max(a.height, b.height),
+      width   = Math.max(a.width, b.width),
+      c       = getImageData(width, height), // c = a - b
+      aData   = a.data,
+      bData   = b.data,
+      cData   = c.data,
+      align   = options && options.align,
+      rowOffset,
+      columnOffset,
+      row, column,
+      i, j, k, v;
+
+
+    for (i = cData.length - 1; i > 0; i = i - 4) {
+      cData[i] = 255;
+    }
+
+    // Add First Image
+    offsets(a);
+    for (row = a.height; row--;){
+      for (column = a.width; column--;) {
+        i = 4 * ((row + rowOffset) * width + (column + columnOffset));
+        j = 4 * (row * a.width + column);
+        cData[i+0] = aData[j+0]; // r
+        cData[i+1] = aData[j+1]; // g
+        cData[i+2] = aData[j+2]; // b
+        // cData[i+3] = aData[j+3]; // a
+      }
+    }
+
+    // Subtract Second Image
+    offsets(b);
+    for (row = b.height; row--;){
+      for (column = b.width; column--;) {
+        i = 4 * ((row + rowOffset) * width + (column + columnOffset));
+        j = 4 * (row * b.width + column);
+        cData[i+0] = Math.abs(cData[i+0] - bData[j+0]); // r
+        cData[i+1] = Math.abs(cData[i+1] - bData[j+1]); // g
+        cData[i+2] = Math.abs(cData[i+2] - bData[j+2]); // b
+      }
+    }
+
+    // Helpers
+    function offsets (imageData) {
+      if (align === 'top') {
+        rowOffset = 0;
+        columnOffset = 0;
+      } else {
+        rowOffset = Math.floor((height - imageData.height) / 2);
+        columnOffset = Math.floor((width - imageData.width) / 2);
+      }
+    }
+
+    return c;
+  }
+
+
+  // Validation
+  function checkType () {
+    var i;
+    for (i = 0; i < arguments.length; i++) {
+      if (!isImageType(arguments[i])) {
+        throw {
+          name : 'ImageTypeError',
+          message : 'Submitted object was not an image.'
+        };
+      }
+    }
+  }
+
+
+  // Jasmine Matchers
+  function get (element, content) {
+    element = document.createElement(element);
+    if (element && content) {
+      element.innerHTML = content;
+    }
+    return element;
+  }
+
+  jasmine = {
+
+    toBeImageData : function () {
+      return imagediff.isImageData(this.actual);
+    },
+
+    toImageDiffEqual : function (expected, tolerance) {
+
+      if (typeof (document) !== UNDEFINED) {
+        this.message = function () {
+          var
+            div     = get('div'),
+            a       = get('div', '<div>Actual:</div>'),
+            b       = get('div', '<div>Expected:</div>'),
+            c       = get('div', '<div>Diff:</div>'),
+            diff    = imagediff.diff(this.actual, expected),
+            canvas  = getCanvas(),
+            context;
+
+          canvas.height = diff.height;
+          canvas.width  = diff.width;
+
+          div.style.overflow = 'hidden';
+          a.style.float = 'left';
+          b.style.float = 'left';
+          c.style.float = 'left';
+
+          context = canvas.getContext('2d');
+          context.putImageData(diff, 0, 0);
+
+          a.appendChild(toCanvas(this.actual));
+          b.appendChild(toCanvas(expected));
+          c.appendChild(canvas);
+
+          div.appendChild(a);
+          div.appendChild(b);
+          div.appendChild(c);
+
+          return [
+            div,
+            "Expected not to be equal."
+          ];
+        };
+      }
+
+      return imagediff.equal(this.actual, expected, tolerance);
+    }
+  };
+
+
+  // Image Output
+  function imageDataToPNG (imageData, outputFile, callback) {
+
+    var
+      canvas = toCanvas(imageData),
+      base64Data,
+      decodedImage;
+
+    callback = callback || Function;
+
+    base64Data = canvas.toDataURL().replace(/^data:image\/\w+;base64,/,"");
+    decodedImage = Buffer.from(base64Data, 'base64');
+    require('fs').writeFile(outputFile, decodedImage, callback);
+  }
+
+
+  // Definition
+  imagediff = {
+
+    createCanvas : getCanvas,
+    createImageData : getImageData,
+    getCanvasRef: getCanvasRef,
+
+    isImage : isImage,
+    isCanvas : isCanvas,
+    isContext : isContext,
+    isImageData : isImageData,
+    isImageType : isImageType,
+
+    toImageData : function (object) {
+      checkType(object);
+      if (isImageData(object)) { return copyImageData(object); }
+      return toImageData(object);
+    },
+
+    equal : function (a, b, tolerance) {
+      checkType(a, b);
+      a = toImageData(a);
+      b = toImageData(b);
+      return equal(a, b, tolerance);
+    },
+    diff : function (a, b, options) {
+      checkType(a, b);
+      a = toImageData(a);
+      b = toImageData(b);
+      return diff(a, b, options);
+    },
+
+    jasmine : jasmine,
+
+    // Compatibility
+    noConflict : function () {
+      root[name] = previous;
+      return imagediff;
+    }
+  };
+
+  if (typeof module !== 'undefined') {
+    imagediff.imageDataToPNG = imageDataToPNG;
+  }
+
+  return imagediff;
+});

test/in/PngSuite.README

@@ -1,25 +1,25 @@
-        PNGSUITE
+        PNGSUITE
-----------------
+----------------
-
+
-        testset for PNG-(de)coders
+        testset for PNG-(de)coders
-        created by Willem van Schaik
+        created by Willem van Schaik
-------------------------------------
+------------------------------------
-
+
-This is a collection of graphics images created to test the png applications
+This is a collection of graphics images created to test the png applications
-like viewers, converters and editors. All (as far as that is possible)
+like viewers, converters and editors. All (as far as that is possible)
-formats supported by the PNG standard are represented.
+formats supported by the PNG standard are represented.
-
+
-The suite consists of the following files:
+The suite consists of the following files:
-
+
--	PngSuite.README		- this file
+-	PngSuite.README		- this file
--	PngSuite.LICENSE	- the PngSuite is freeware
+-	PngSuite.LICENSE	- the PngSuite is freeware
--	PngSuite.png		- image with PngSuite logo
+-	PngSuite.png		- image with PngSuite logo
--	PngSuite.tgz		- archive of all PNG testfiles
+-	PngSuite.tgz		- archive of all PNG testfiles
--	PngSuite.zip		- same in .zip format for PCs
+-	PngSuite.zip		- same in .zip format for PCs
-
+
-
+
---------
+--------
-    (c) Willem van Schaik
+    (c) Willem van Schaik
-	willem@schaik.com
+	willem@schaik.com
-        Calgary, April 2011
+        Calgary, April 2011
-
+