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https://github.com/danbulant/pngjs
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Merge remote-tracking branch 'origin/sync'
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Luke Page
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4def219e1e
2 changed files with 369 additions and 9 deletions
361
lib/parser-base.js
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361
lib/parser-base.js
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// Copyright (c) 2012 Kuba Niegowski
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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'use strict';
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var util = require('util'),
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zlib = require('zlib'),
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CrcStream = require('./crc'),
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ChunkStream = require('./chunkstream'),
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constants = require('./constants'),
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Filter = require('./filter');
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var Parser = module.exports = function(options, dependencies) {
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this._options = options;
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options.checkCRC = options.checkCRC !== false;
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this._hasIHDR = false;
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this._hasIEND = false;
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this._inflate = null;
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this._filter = null;
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this._crc = null;
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// input flags/metadata
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this._palette = [];
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this._colorType = 0;
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this._chunks = {};
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this._chunks[constants.TYPE_IHDR] = this._handleIHDR.bind(this);
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this._chunks[constants.TYPE_IEND] = this._handleIEND.bind(this);
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this._chunks[constants.TYPE_IDAT] = this._handleIDAT.bind(this);
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this._chunks[constants.TYPE_PLTE] = this._handlePLTE.bind(this);
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this._chunks[constants.TYPE_tRNS] = this._handleTRNS.bind(this);
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this._chunks[constants.TYPE_gAMA] = this._handleGAMA.bind(this);
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this.writable = true;
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//this.on('error', this._handleError.bind(this));
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//this._handleSignature();
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this.read = dependencies.read;
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this.error = dependencies.error;
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};
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util.inherits(Parser, ChunkStream);
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Parser.prototype._handleError = function() {
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this.writable = false;
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this.destroy();
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if (this._inflate)
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this._inflate.destroy();
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};
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Parser.prototype.start = function() {
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this.read(constants.PNG_SIGNATURE.length,
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this._parseSignature.bind(this)
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);
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};
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Parser.prototype._parseSignature = function(data) {
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var signature = constants.PNG_SIGNATURE;
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for (var i = 0; i < signature.length; i++) {
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if (data[i] != signature[i]) {
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this.error(new Error('Invalid file signature'));
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return;
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}
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}
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this.read(8, this._parseChunkBegin.bind(this));
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};
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Parser.prototype._parseChunkBegin = function(data) {
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// chunk content length
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var length = data.readUInt32BE(0);
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// chunk type
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var type = data.readUInt32BE(4),
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name = '';
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for (var i = 4; i < 8; i++)
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name += String.fromCharCode(data[i]);
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// console.log('chunk ', name, length);
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// chunk flags
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var ancillary = !!(data[4] & 0x20), // or critical
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priv = !!(data[5] & 0x20), // or public
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safeToCopy = !!(data[7] & 0x20); // or unsafe
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if (!this._hasIHDR && type != constants.TYPE_IHDR) {
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this.error(new Error('Expected IHDR on beggining'));
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return;
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}
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// this._crc = new CrcStream();
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// this._crc.write(new Buffer(name));
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if (this._chunks[type]) {
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return this._chunks[type](length);
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} else if (!ancillary) {
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this.error(new Error('Unsupported critical chunk type ' + name));
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return;
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} else {
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this.read(length + 4, this._skipChunk.bind(this));
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}
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};
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Parser.prototype._skipChunk = function(data) {
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this.read(8, this._parseChunkBegin.bind(this));
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};
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Parser.prototype._handleChunkEnd = function() {
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this.read(4, this._parseChunkEnd.bind(this));
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};
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Parser.prototype._parseChunkEnd = function(data) {
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var fileCrc = data.readInt32BE(0),
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calcCrc = this._crc.crc32();
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// check CRC
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if (this._options.checkCRC && calcCrc != fileCrc) {
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this.error(new Error('Crc error'));
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return;
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}
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if (this._hasIEND) {
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this.destroySoon();
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} else {
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// todo allow _parseSignature to loop chinks?
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this.read(8, this._parseChunkBegin.bind(this));
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}
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};
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Parser.prototype._handleIHDR = function(length) {
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this.read(length, this._parseIHDR.bind(this));
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};
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Parser.prototype._parseIHDR = function(data) {
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this._crc.write(data);
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var width = data.readUInt32BE(0),
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height = data.readUInt32BE(4),
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depth = data[8],
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colorType = data[9], // bits: 1 palette, 2 color, 4 alpha
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compr = data[10],
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filter = data[11],
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interlace = data[12];
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// console.log(' width', width, 'height', height,
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// 'depth', depth, 'colorType', colorType,
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// 'compr', compr, 'filter', filter, 'interlace', interlace
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// );
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if (depth != 8) {
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this.error(new Error('Unsupported bit depth ' + depth));
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return;
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}
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if (!(colorType in colorTypeToBppMap)) {
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this.error(new Error('Unsupported color type'));
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return;
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}
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if (compr != 0) {
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this.error(new Error('Unsupported compression method'));
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return;
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}
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if (filter != 0) {
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this.error(new Error('Unsupported filter method'));
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return;
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}
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if (interlace != 0) {
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this.error(new Error('Unsupported interlace method'));
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return;
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}
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this._colorType = colorType;
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this._data = new Buffer(width * height * 4);
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this._filter = new Filter(
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width, height,
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colorTypeToBppMap[this._colorType],
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this._data,
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this._options
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);
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this._hasIHDR = true;
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this.metadata({
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width: width,
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height: height,
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palette: !!(colorType & constants.COLOR_PALETTE),
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color: !!(colorType & constants.COLOR_COLOR),
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alpha: !!(colorType & constants.COLOR_ALPHA),
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data: this._data
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});
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this._handleChunkEnd();
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};
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Parser.prototype._handlePLTE = function(length) {
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this.read(length, this._parsePLTE.bind(this));
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};
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Parser.prototype._parsePLTE = function(data) {
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this._crc.write(data);
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var entries = Math.floor(data.length / 3);
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// console.log('Palette:', entries);
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for (var i = 0; i < entries; i++) {
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this._palette.push([
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data.readUInt8(i * 3),
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data.readUInt8(i * 3 + 1),
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data.readUInt8(i * 3 + 2 ),
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0xff
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]);
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}
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this._handleChunkEnd();
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};
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Parser.prototype._handleTRNS = function(length) {
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this.read(length, this._parseTRNS.bind(this));
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};
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Parser.prototype._parseTRNS = function(data) {
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this._crc.write(data);
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// palette
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if (this._colorType == 3) {
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if (this._palette.length == 0) {
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this.error(new Error('Transparency chunk must be after palette'));
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return;
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}
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if (data.length > this._palette.length) {
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this.error(new Error('More transparent colors than palette size'));
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return;
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}
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for (var i = 0; i < this._palette.length; i++) {
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this._palette[i][3] = i < data.length ? data.readUInt8(i) : 0xff;
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}
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}
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// for colorType 0 (grayscale) and 2 (rgb)
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// there might be one gray/color defined as transparent
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this._handleChunkEnd();
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};
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Parser.prototype._handleGAMA = function(length) {
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this.read(length, this._parseGAMA.bind(this));
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};
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Parser.prototype._parseGAMA = function(data) {
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this._crc.write(data);
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this.gamma(data.readUInt32BE(0) / 100000);
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this._handleChunkEnd();
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};
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Parser.prototype._handleIDAT = function(length) {
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this.read(-length, this._parseIDAT.bind(this, length));
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};
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Parser.prototype._parseIDAT = function(length, data) {
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this._crc.write(data);
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if (this._colorType == 3 && this._palette.length == 0)
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throw new Error('Expected palette not found');
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if (!this._inflate) {
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this._inflate = zlib.createInflate();
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this._inflate.on('error', this.emit.bind(this, 'error'));
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this._filter.on('complete', this._reverseFiltered.bind(this));
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this._inflate.pipe(this._filter);
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}
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this._inflate.write(data);
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length -= data.length;
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if (length > 0)
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this._handleIDAT(length);
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else
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this._handleChunkEnd();
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};
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Parser.prototype._handleIEND = function(length) {
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this.read(length, this._parseIEND.bind(this));
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};
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Parser.prototype._parseIEND = function(data) {
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this._crc.write(data);
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// no more data to inflate
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this._inflate.end();
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this._hasIEND = true;
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this._handleChunkEnd();
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};
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var colorTypeToBppMap = {
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0: 1,
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2: 3,
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3: 1,
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4: 2,
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6: 4
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};
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Parser.prototype._reverseFiltered = function(data, width, height) {
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if (this._colorType == 3) { // paletted
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// use values from palette
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var pxLineLength = width << 2;
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for (var y = 0; y < height; y++) {
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var pxRowPos = y * pxLineLength;
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for (var x = 0; x < width; x++) {
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var pxPos = pxRowPos + (x << 2),
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color = this._palette[data[pxPos]];
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for (var i = 0; i < 4; i++)
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data[pxPos + i] = color[i];
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}
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}
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}
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this.emit('parsed', data);
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};
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17
package.json
17
package.json
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@ -1,10 +1,9 @@
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{
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"name": "node-png",
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"version": "0.4.3",
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"description": "Simple PNG encoder/decoder",
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"author": "Kuba Niegowski",
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"contributors": [],
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"homepage": "https://github.com/brighthas/node-pngjs/",
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"name": "pngjs2",
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"version": "1.0.0",
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"description": "Pure JS PNG encoder/decoder",
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"contributors": ["Kuba Niegowski", "Luke Page", "Pietajan De Potter", "Steven Sojka", "Alexandre Paré", "Gaurav Mali", "liangzeng"],
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"homepage": "https://github.com/lukeapage/pngjs2",
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"keywords": [
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"png"
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],
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"example": "examples"
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},
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"scripts": {
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"test": "echo \"Error: no test specified\" && exit 1"
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"test": "node test/test"
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},
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"repository": {
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"type": "git",
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"url": "git://github.com/brighthas/node-pngjs.git"
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"url": "git://github.com/lukeapage/pngjs2.git"
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},
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"license": "MIT",
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"bugs": {
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"url": "https://github.com/brighthas/node-pngjs/issues"
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"url": "https://github.com/lukeapage/pngjs2/issues"
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}
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}
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