colonymech / docs / www / colonyscout / internal / includes / uploadify / com / adobe / images / PNGEncoder.as @ f59acf11
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/* |
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Copyright (c) 2008, Adobe Systems Incorporated |
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All rights reserved. |
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|
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Redistribution and use in source and binary forms, with or without |
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modification, are permitted provided that the following conditions are |
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met: |
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|
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* Redistributions of source code must retain the above copyright notice, |
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this list of conditions and the following disclaimer. |
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|
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* Redistributions in binary form must reproduce the above copyright |
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notice, this list of conditions and the following disclaimer in the |
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documentation and/or other materials provided with the distribution. |
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|
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* Neither the name of Adobe Systems Incorporated nor the names of its |
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contributors may be used to endorse or promote products derived from |
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this software without specific prior written permission. |
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|
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
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IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
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THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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package com.adobe.images |
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{ |
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import flash.geom.*; |
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import flash.display.Bitmap; |
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import flash.display.BitmapData; |
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import flash.utils.ByteArray; |
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|
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/** |
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* Class that converts BitmapData into a valid PNG |
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*/ |
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public class PNGEncoder |
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{ |
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/** |
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* Created a PNG image from the specified BitmapData |
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* |
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* @param image The BitmapData that will be converted into the PNG format. |
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* @return a ByteArray representing the PNG encoded image data. |
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* @langversion ActionScript 3.0 |
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* @playerversion Flash 9.0 |
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* @tiptext |
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*/ |
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public static function encode(img:BitmapData):ByteArray { |
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// Create output byte array |
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var png:ByteArray = new ByteArray(); |
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// Write PNG signature |
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png.writeUnsignedInt(0x89504e47); |
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png.writeUnsignedInt(0x0D0A1A0A); |
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// Build IHDR chunk |
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var IHDR:ByteArray = new ByteArray(); |
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IHDR.writeInt(img.width); |
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IHDR.writeInt(img.height); |
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IHDR.writeUnsignedInt(0x08060000); // 32bit RGBA |
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IHDR.writeByte(0); |
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writeChunk(png,0x49484452,IHDR); |
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// Build IDAT chunk |
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var IDAT:ByteArray= new ByteArray(); |
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for(var i:int=0;i < img.height;i++) { |
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// no filter |
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IDAT.writeByte(0); |
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var p:uint; |
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var j:int; |
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if ( !img.transparent ) { |
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for(j=0;j < img.width;j++) { |
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p = img.getPixel(j,i); |
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IDAT.writeUnsignedInt( |
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uint(((p&0xFFFFFF) << 8)|0xFF)); |
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} |
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} else { |
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for(j=0;j < img.width;j++) { |
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p = img.getPixel32(j,i); |
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IDAT.writeUnsignedInt( |
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uint(((p&0xFFFFFF) << 8)| |
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(p>>>24))); |
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} |
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} |
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} |
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IDAT.compress(); |
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writeChunk(png,0x49444154,IDAT); |
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// Build IEND chunk |
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writeChunk(png,0x49454E44,null); |
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// return PNG |
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return png; |
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} |
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|
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private static var crcTable:Array; |
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private static var crcTableComputed:Boolean = false; |
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|
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private static function writeChunk(png:ByteArray, |
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type:uint, data:ByteArray):void { |
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if (!crcTableComputed) { |
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crcTableComputed = true; |
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crcTable = []; |
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var c:uint; |
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for (var n:uint = 0; n < 256; n++) { |
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c = n; |
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for (var k:uint = 0; k < 8; k++) { |
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if (c & 1) { |
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c = uint(uint(0xedb88320) ^ |
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uint(c >>> 1)); |
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} else { |
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c = uint(c >>> 1); |
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} |
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} |
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crcTable[n] = c; |
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} |
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} |
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var len:uint = 0; |
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if (data != null) { |
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len = data.length; |
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} |
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png.writeUnsignedInt(len); |
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var p:uint = png.position; |
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png.writeUnsignedInt(type); |
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if ( data != null ) { |
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png.writeBytes(data); |
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} |
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var e:uint = png.position; |
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png.position = p; |
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c = 0xffffffff; |
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for (var i:int = 0; i < (e-p); i++) { |
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c = uint(crcTable[ |
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(c ^ png.readUnsignedByte()) & |
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uint(0xff)] ^ uint(c >>> 8)); |
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} |
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c = uint(c^uint(0xffffffff)); |
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png.position = e; |
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png.writeUnsignedInt(c); |
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} |
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} |
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} |