forked from Mirrors/freeswitch
141 lines
5.1 KiB
ActionScript
141 lines
5.1 KiB
ActionScript
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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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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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* 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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* 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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* 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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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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* 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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private static var crcTable:Array;
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private static var crcTableComputed:Boolean = false;
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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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}
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