手上有台android的平板，性能感觉还不错，创建了一个ActionScript手机项目玩玩，想通过截取屏幕，生成一张图片到平板的相册中。
目前在windows+flash builder，在模拟器下在widnows本地成功生成了jpg和png图片，在android平板上也成功了，虽然路径并不是android相册以至于现在还未找到图片在哪里...
大体流程就是：
通过BitmapData，draw出你想要的区域---->
利用Adobe官方的JPGEncoder后者PNGEncoder，对bitmapdata进行编码，并存储到一个二进制数组中，好吧就是ByteArray------>
利用File获取本地可以存储路径，然后用FileStream文件流将byteArray写入到本地,即开始生成图片，当然，可以使用同步或者异步的方式写文件(虽然我并没有看到同步可异步的区别在哪里，同样的画面会停顿...)
ok,上码:
1 var bmpData:BitmapData = new BitmapData(width,height); 2 bmpData.draw(this); 3 4 5 var jpgCoder:JPGEncoder = new JPGEncoder(); 6 var bytes:ByteArray = jpgCoder.encode(bmpData); 7 8 9 10 11 var now:Date = new Date(); 12 var year:Number=now.getFullYear();//年 13 var month:Number=now.getMonth()+1;//月 14 var day:Number=now.getDate();//日 15 16 var hour:Number = now.getHours();//时 17 var min:Number = now.getMinutes();//分 18 var sec:Number = now.getSeconds();//秒 19 20 21 var fileName:String = "word_" + year + month + day + hour + min + sec; 22 var fileFullName:String = File.applicationStorageDirectory.resolvePath("img/"+ fileName +".jpg").nativePath; 23 var file:File = new File(fileFullName); 24 trace(file.nativePath); 25 var stream:FileStream = new FileStream(); 26 stream.open(file,FileMode.WRITE); 27 stream.addEventListener(IOErrorEvent.IO_ERROR,writeIOErrorHandler); 28 stream.addEventListener(Event.COMPLETE, writeCompleteHandler); 29 stream.writeBytes(bytes); 30 stream.close();
从第6行走到第11行需要等待一到两秒钟，我的cpu是i5的，可见JPGEncoder编码是比较费运算的。
如果把以上代码的第5，6行注释掉换成
var bytes:ByteArray = PNGEncoder.encode(bmpData);
发现会快很多，几乎是感觉不到停顿，脑海中突然想起一兄弟曾经说过的一句话:"png的编码方式比jpg要快的多...",注意如果要使用png,那么生成的图片的后缀名也最好是.png
这里也直接把adobe官方的JPGEncoder相关类贴出：http://as3corelib.googlecode.com/svn/trunk/src/com/adobe/images/
/* Copyright (c) 2008, Adobe Systems Incorporated All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of Adobe Systems Incorporated nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package { import flash.geom.*; import flash.display.*; import flash.utils.*; /** * Class that converts BitmapData into a valid JPEG */ public class JPGEncoder { // Static table initialization private var ZigZag:Array = [ 0, 1, 5, 6,14,15,27,28, 2, 4, 7,13,16,26,29,42, 3, 8,12,17,25,30,41,43, 9,11,18,24,31,40,44,53, 10,19,23,32,39,45,52,54, 20,22,33,38,46,51,55,60, 21,34,37,47,50,56,59,61, 35,36,48,49,57,58,62,63 ]; private var YTable:Array = new Array(64); private var UVTable:Array = new Array(64); private var fdtbl_Y:Array = new Array(64); private var fdtbl_UV:Array = new Array(64); private function initQuantTables(sf:int):void { var i:int; var t:Number; var YQT:Array = [ 16, 11, 10, 16, 24, 40, 51, 61, 12, 12, 14, 19, 26, 58, 60, 55, 14, 13, 16, 24, 40, 57, 69, 56, 14, 17, 22, 29, 51, 87, 80, 62, 18, 22, 37, 56, 68,109,103, 77, 24, 35, 55, 64, 81,104,113, 92, 49, 64, 78, 87,103,121,120,101, 72, 92, 95, 98,112,100,103, 99 ]; for (i = 0; i < 64; i++) { t = Math.floor((YQT[i]*sf+50)/100); if (t < 1) { t = 1; } else if (t > 255) { t = 255; } YTable[ZigZag[i]] = t; } var UVQT:Array = [ 17, 18, 24, 47, 99, 99, 99, 99, 18, 21, 26, 66, 99, 99, 99, 99, 24, 26, 56, 99, 99, 99, 99, 99, 47, 66, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99 ]; for (i = 0; i < 64; i++) { t = Math.floor((UVQT[i]*sf+50)/100); if (t < 1) { t = 1; } else if (t > 255) { t = 255; } UVTable[ZigZag[i]] = t; } var aasf:Array = [ 1.0, 1.387039845, 1.306562965, 1.175875602, 1.0, 0.785694958, 0.541196100, 0.275899379 ]; i = 0; for (var row:int = 0; row < 8; row++) { for (var col:int = 0; col < 8; col++) { fdtbl_Y[i] = (1.0 / (YTable [ZigZag[i]] * aasf[row] * aasf[col] * 8.0)); fdtbl_UV[i] = (1.0 / (UVTable[ZigZag[i]] * aasf[row] * aasf[col] * 8.0)); i++; } } } private var YDC_HT:Array; private var UVDC_HT:Array; private var YAC_HT:Array; private var UVAC_HT:Array; private function computeHuffmanTbl(nrcodes:Array, std_table:Array):Array { var codevalue:int = 0; var pos_in_table:int = 0; var HT:Array = new Array(); for (var k:int=1; k<=16; k++) { for (var j:int=1; j<=nrcodes[k]; j++) { HT[std_table[pos_in_table]] = new BitString(); HT[std_table[pos_in_table]].val = codevalue; HT[std_table[pos_in_table]].len = k; pos_in_table++; codevalue++; } codevalue*=2; } return HT; } private var std_dc_luminance_nrcodes:Array = [0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0]; private var std_dc_luminance_values:Array = [0,1,2,3,4,5,6,7,8,9,10,11]; private var std_ac_luminance_nrcodes:Array = [0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d]; private var std_ac_luminance_values:Array = [ 0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12, 0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07, 0x22,0x71,0x14,0x32,0x81,0x91,0xa1,0x08, 0x23,0x42,0xb1,0xc1,0x15,0x52,0xd1,0xf0, 0x24,0x33,0x62,0x72,0x82,0x09,0x0a,0x16, 0x17,0x18,0x19,0x1a,0x25,0x26,0x27,0x28, 0x29,0x2a,0x34,0x35,0x36,0x37,0x38,0x39, 0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49, 0x4a,0x53,0x54,0x55,0x56,0x57,0x58,0x59, 0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69, 0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79, 0x7a,0x83,0x84,0x85,0x86,0x87,0x88,0x89, 0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98, 0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7, 0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,0xb5,0xb6, 0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5, 0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4, 0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xe1,0xe2, 0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea, 0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8, 0xf9,0xfa ]; private var std_dc_chrominance_nrcodes:Array = [0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0]; private var std_dc_chrominance_values:Array = [0,1,2,3,4,5,6,7,8,9,10,11]; private var std_ac_chrominance_nrcodes:Array = [0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77]; private var std_ac_chrominance_values:Array = [ 0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21, 0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71, 0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91, 0xa1,0xb1,0xc1,0x09,0x23,0x33,0x52,0xf0, 0x15,0x62,0x72,0xd1,0x0a,0x16,0x24,0x34, 0xe1,0x25,0xf1,0x17,0x18,0x19,0x1a,0x26, 0x27,0x28,0x29,0x2a,0x35,0x36,0x37,0x38, 0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48, 0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58, 0x59,0x5a,0x63,0x64,0x65,0x66,0x67,0x68, 0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78, 0x79,0x7a,0x82,0x83,0x84,0x85,0x86,0x87, 0x88,0x89,0x8a,0x92,0x93,0x94,0x95,0x96, 0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5, 0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4, 0xb5,0xb6,0xb7,0xb8,0xb9,0xba,0xc2,0xc3, 0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2, 0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda, 0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9, 0xea,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8, 0xf9,0xfa ]; private function initHuffmanTbl():void { YDC_HT = computeHuffmanTbl(std_dc_luminance_nrcodes,std_dc_luminance_values); UVDC_HT = computeHuffmanTbl(std_dc_chrominance_nrcodes,std_dc_chrominance_values); YAC_HT = computeHuffmanTbl(std_ac_luminance_nrcodes,std_ac_luminance_values); UVAC_HT = computeHuffmanTbl(std_ac_chrominance_nrcodes,std_ac_chrominance_values); } private var bitcode:Array = new Array(65535); private var category:Array = new Array(65535); private function initCategoryNumber():void { var nrlower:int = 1; var nrupper:int = 2; var nr:int; for (var cat:int=1; cat<=15; cat++) { //Positive numbers for (nr=nrlower; nr<nrupper; nr++) { category[32767+nr] = cat; bitcode[32767+nr] = new BitString(); bitcode[32767+nr].len = cat; bitcode[32767+nr].val = nr; } //Negative numbers for (nr=-(nrupper-1); nr<=-nrlower; nr++) { category[32767+nr] = cat; bitcode[32767+nr] = new BitString(); bitcode[32767+nr].len = cat; bitcode[32767+nr].val = nrupper-1+nr; } nrlower <<= 1; nrupper <<= 1; } } // IO functions private var byteout:ByteArray; private var bytenew:int = 0; private var bytepos:int = 7; private function writeBits(bs:BitString):void { var value:int = bs.val; var posval:int = bs.len-1; while ( posval >= 0 ) { if (value & uint(1 << posval) ) { bytenew |= uint(1 << bytepos); } posval--; bytepos--; if (bytepos < 0) { if (bytenew == 0xFF) { writeByte(0xFF); writeByte(0); } else { writeByte(bytenew); } bytepos=7; bytenew=0; } } } private function writeByte(value:int):void { byteout.writeByte(value); } private function writeWord(value:int):void { writeByte((value>>8)&0xFF); writeByte((value )&0xFF); } // DCT & quantization core private function fDCTQuant(data:Array, fdtbl:Array):Array { var tmp0:Number, tmp1:Number, tmp2:Number, tmp3:Number, tmp4:Number, tmp5:Number, tmp6:Number, tmp7:Number; var tmp10:Number, tmp11:Number, tmp12:Number, tmp13:Number; var z1:Number, z2:Number, z3:Number, z4:Number, z5:Number, z11:Number, z13:Number; var i:int; /* Pass 1: process rows. */ var dataOff:int=0; for (i=0; i<8; i++) { tmp0 = data[dataOff+0] + data[dataOff+7]; tmp7 = data[dataOff+0] - data[dataOff+7]; tmp1 = data[dataOff+1] + data[dataOff+6]; tmp6 = data[dataOff+1] - data[dataOff+6]; tmp2 = data[dataOff+2] + data[dataOff+5]; tmp5 = data[dataOff+2] - data[dataOff+5]; tmp3 = data[dataOff+3] + data[dataOff+4]; tmp4 = data[dataOff+3] - data[dataOff+4]; /* Even part */ tmp10 = tmp0 + tmp3; /* phase 2 */ tmp13 = tmp0 - tmp3; tmp11 = tmp1 + tmp2; tmp12 = tmp1 - tmp2; data[dataOff+0] = tmp10 + tmp11; /* phase 3 */ data[dataOff+4] = tmp10 - tmp11; z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */ data[dataOff+2] = tmp13 + z1; /* phase 5 */ data[dataOff+6] = tmp13 - z1; /* Odd part */ tmp10 = tmp4 + tmp5; /* phase 2 */ tmp11 = tmp5 + tmp6; tmp12 = tmp6 + tmp7; /* The rotator is modified from fig 4-8 to avoid extra negations. */ z5 = (tmp10 - tmp12) * 0.382683433; /* c6 */ z2 = 0.541196100 * tmp10 + z5; /* c2-c6 */ z4 = 1.306562965 * tmp12 + z5; /* c2+c6 */ z3 = tmp11 * 0.707106781; /* c4 */ z11 = tmp7 + z3; /* phase 5 */ z13 = tmp7 - z3; data[dataOff+5] = z13 + z2; /* phase 6 */ data[dataOff+3] = z13 - z2; data[dataOff+1] = z11 + z4; data[dataOff+7] = z11 - z4; dataOff += 8; /* advance pointer to next row */ } /* Pass 2: process columns. */ dataOff = 0; for (i=0; i<8; i++) { tmp0 = data[dataOff+ 0] + data[dataOff+56]; tmp7 = data[dataOff+ 0] - data[dataOff+56]; tmp1 = data[dataOff+ 8] + data[dataOff+48]; tmp6 = data[dataOff+ 8] - data[dataOff+48]; tmp2 = data[dataOff+16] + data[dataOff+40]; tmp5 = data[dataOff+16] - data[dataOff+40]; tmp3 = data[dataOff+24] + data[dataOff+32]; tmp4 = data[dataOff+24] - data[dataOff+32]; /* Even part */ tmp10 = tmp0 + tmp3; /* phase 2 */ tmp13 = tmp0 - tmp3; tmp11 = tmp1 + tmp2; tmp12 = tmp1 - tmp2; data[dataOff+ 0] = tmp10 + tmp11; /* phase 3 */ data[dataOff+32] = tmp10 - tmp11; z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */ data[dataOff+16] = tmp13 + z1; /* phase 5 */ data[dataOff+48] = tmp13 - z1; /* Odd part */ tmp10 = tmp4 + tmp5; /* phase 2 */ tmp11 = tmp5 + tmp6; tmp12 = tmp6 + tmp7; /* The rotator is modified from fig 4-8 to avoid extra negations. */ z5 = (tmp10 - tmp12) * 0.382683433; /* c6 */ z2 = 0.541196100 * tmp10 + z5; /* c2-c6 */ z4 = 1.306562965 * tmp12 + z5; /* c2+c6 */ z3 = tmp11 * 0.707106781; /* c4 */ z11 = tmp7 + z3; /* phase 5 */ z13 = tmp7 - z3; data[dataOff+40] = z13 + z2; /* phase 6 */ data[dataOff+24] = z13 - z2; data[dataOff+ 8] = z11 + z4; data[dataOff+56] = z11 - z4; dataOff++; /* advance pointer to next column */ } // Quantize/descale the coefficients for (i=0; i<64; i++) { // Apply the quantization and scaling factor & Round to nearest integer data[i] = Math.round((data[i]*fdtbl[i])); } return data; } // Chunk writing private function writeAPP0():void { writeWord(0xFFE0); // marker writeWord(16); // length writeByte(0x4A); // J writeByte(0x46); // F writeByte(0x49); // I writeByte(0x46); // F writeByte(0); // = "JFIF",'\0' writeByte(1); // versionhi writeByte(1); // versionlo writeByte(0); // xyunits writeWord(1); // xdensity writeWord(1); // ydensity writeByte(0); // thumbnwidth writeByte(0); // thumbnheight } private function writeSOF0(int, height:int):void { writeWord(0xFFC0); // marker writeWord(17); // length, truecolor YUV JPG writeByte(8); // precision writeWord(height); writeWord(width); writeByte(3); // nrofcomponents writeByte(1); // IdY writeByte(0x11); // HVY writeByte(0); // QTY writeByte(2); // IdU writeByte(0x11); // HVU writeByte(1); // QTU writeByte(3); // IdV writeByte(0x11); // HVV writeByte(1); // QTV } private function writeDQT():void { writeWord(0xFFDB); // marker writeWord(132); // length writeByte(0); var i:int; for (i=0; i<64; i++) { writeByte(YTable[i]); } writeByte(1); for (i=0; i<64; i++) { writeByte(UVTable[i]); } } private function writeDHT():void { writeWord(0xFFC4); // marker writeWord(0x01A2); // length var i:int; writeByte(0); // HTYDCinfo for (i=0; i<16; i++) { writeByte(std_dc_luminance_nrcodes[i+1]); } for (i=0; i<=11; i++) { writeByte(std_dc_luminance_values[i]); } writeByte(0x10); // HTYACinfo for (i=0; i<16; i++) { writeByte(std_ac_luminance_nrcodes[i+1]); } for (i=0; i<=161; i++) { writeByte(std_ac_luminance_values[i]); } writeByte(1); // HTUDCinfo for (i=0; i<16; i++) { writeByte(std_dc_chrominance_nrcodes[i+1]); } for (i=0; i<=11; i++) { writeByte(std_dc_chrominance_values[i]); } writeByte(0x11); // HTUACinfo for (i=0; i<16; i++) { writeByte(std_ac_chrominance_nrcodes[i+1]); } for (i=0; i<=161; i++) { writeByte(std_ac_chrominance_values[i]); } } private function writeSOS():void { writeWord(0xFFDA); // marker writeWord(12); // length writeByte(3); // nrofcomponents writeByte(1); // IdY writeByte(0); // HTY writeByte(2); // IdU writeByte(0x11); // HTU writeByte(3); // IdV writeByte(0x11); // HTV writeByte(0); // Ss writeByte(0x3f); // Se writeByte(0); // Bf } // Core processing private var DU:Array = new Array(64); private function processDU(CDU:Array, fdtbl:Array, DC:Number, HTDC:Array, HTAC:Array):Number { var EOB:BitString = HTAC[0x00]; var M16zeroes:BitString = HTAC[0xF0]; var i:int; var DU_DCT:Array = fDCTQuant(CDU, fdtbl); //ZigZag reorder for (i=0;i<64;i++) { DU[ZigZag[i]]=DU_DCT[i]; } var Diff:int = DU[0] - DC; DC = DU[0]; //Encode DC if (Diff==0) { writeBits(HTDC[0]); // Diff might be 0 } else { writeBits(HTDC[category[32767+Diff]]); writeBits(bitcode[32767+Diff]); } //Encode ACs var end0pos:int = 63; for (; (end0pos>0)&&(DU[end0pos]==0); end0pos--) { }; //end0pos = first element in reverse order !=0 if ( end0pos == 0) { writeBits(EOB); return DC; } i = 1; while ( i <= end0pos ) { var startpos:int = i; for (; (DU[i]==0) && (i<=end0pos); i++) { } var nrzeroes:int = i-startpos; if ( nrzeroes >= 16 ) { for (var nrmarker:int=1; nrmarker <= nrzeroes/16; nrmarker++) { writeBits(M16zeroes); } nrzeroes = int(nrzeroes&0xF); } writeBits(HTAC[nrzeroes*16+category[32767+DU[i]]]); writeBits(bitcode[32767+DU[i]]); i++; } if ( end0pos != 63 ) { writeBits(EOB); } return DC; } private var YDU:Array = new Array(64); private var UDU:Array = new Array(64); private var VDU:Array = new Array(64); private function RGB2YUV(img:BitmapData, xpos:int, ypos:int):void { var pos:int=0; for (var y:int=0; y<8; y++) { for (var x:int=0; x<8; x++) { var P:uint = img.getPixel32(xpos+x,ypos+y); var R:Number = Number((P>>16)&0xFF); var G:Number = Number((P>> 8)&0xFF); var B:Number = Number((P )&0xFF); YDU[pos]=((( 0.29900)*R+( 0.58700)*G+( 0.11400)*B))-128; UDU[pos]=(((-0.16874)*R+(-0.33126)*G+( 0.50000)*B)); VDU[pos]=((( 0.50000)*R+(-0.41869)*G+(-0.08131)*B)); pos++; } } } /** * Constructor for JPEGEncoder class * * @param quality The quality level between 1 and 100 that detrmines the * level of compression used in the generated JPEG * @langversion ActionScript 3.0 * @playerversion Flash 9.0 * @tiptext */ public function JPGEncoder(quality:Number = 50) { if (quality <= 0) { quality = 1; } if (quality > 100) { quality = 100; } var sf:int = 0; if (quality < 50) { sf = int(5000 / quality); } else { sf = int(200 - quality*2); } // Create tables initHuffmanTbl(); initCategoryNumber(); initQuantTables(sf); } /** * Created a JPEG image from the specified BitmapData * * @param image The BitmapData that will be converted into the JPEG format. * @return a ByteArray representing the JPEG encoded image data. * @langversion ActionScript 3.0 * @playerversion Flash 9.0 * @tiptext */ public function encode(image:BitmapData):ByteArray { // Initialize bit writer byteout = new ByteArray(); bytenew=0; bytepos=7; // Add JPEG headers writeWord(0xFFD8); // SOI writeAPP0(); writeDQT(); writeSOF0(image.width,image.height); writeDHT(); writeSOS(); // Encode 8x8 macroblocks var DCY:Number=0; var DCU:Number=0; var DCV:Number=0; bytenew=0; bytepos=7; for (var ypos:int=0; ypos<image.height; ypos+=8) { for (var xpos:int=0; xpos<image.width; xpos+=8) { RGB2YUV(image, xpos, ypos); DCY = processDU(YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT); DCU = processDU(UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT); DCV = processDU(VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT); } } // Do the bit alignment of the EOI marker if ( bytepos >= 0 ) { var fillbits:BitString = new BitString(); fillbits.len = bytepos+1; fillbits.val = (1<<(bytepos+1))-1; writeBits(fillbits); } writeWord(0xFFD9); //EOI return byteout; } } }
/* Copyright (c) 2008, Adobe Systems Incorporated All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of Adobe Systems Incorporated nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package { public class BitString { public var len:int = 0; public var val:int = 0; } }
/* Copyright (c) 2008, Adobe Systems Incorporated All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of Adobe Systems Incorporated nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package { import flash.geom.*; import flash.display.Bitmap; import flash.display.BitmapData; import flash.utils.ByteArray; /** * Class that converts BitmapData into a valid PNG */ public class PNGEncoder { /** * Created a PNG image from the specified BitmapData * * @param image The BitmapData that will be converted into the PNG format. * @return a ByteArray representing the PNG encoded image data. * @langversion ActionScript 3.0 * @playerversion Flash 9.0 * @tiptext */ public static function encode(img:BitmapData):ByteArray { // Create output byte array var png:ByteArray = new ByteArray(); // Write PNG signature png.writeUnsignedInt(0x89504e47); png.writeUnsignedInt(0x0D0A1A0A); // Build IHDR chunk var IHDR:ByteArray = new ByteArray(); IHDR.writeInt(img.width); IHDR.writeInt(img.height); IHDR.writeUnsignedInt(0x08060000); // 32bit RGBA IHDR.writeByte(0); writeChunk(png,0x49484452,IHDR); // Build IDAT chunk var IDAT:ByteArray= new ByteArray(); for(var i:int=0;i < img.height;i++) { // no filter IDAT.writeByte(0); var p:uint; var j:int; if ( !img.transparent ) { for(j=0;j < img.width;j++) { p = img.getPixel(j,i); IDAT.writeUnsignedInt( uint(((p&0xFFFFFF) << 8)|0xFF)); } } else { for(j=0;j < img.width;j++) { p = img.getPixel32(j,i); IDAT.writeUnsignedInt( uint(((p&0xFFFFFF) << 8)| (p>>>24))); } } } IDAT.compress(); writeChunk(png,0x49444154,IDAT); // Build IEND chunk writeChunk(png,0x49454E44,null); // return PNG return png; } private static var crcTable:Array; private static var crcTableComputed:Boolean = false; private static function writeChunk(png:ByteArray, type:uint, data:ByteArray):void { if (!crcTableComputed) { crcTableComputed = true; crcTable = []; var c:uint; for (var n:uint = 0; n < 256; n++) { c = n; for (var k:uint = 0; k < 8; k++) { if (c & 1) { c = uint(uint(0xedb88320) ^ uint(c >>> 1)); } else { c = uint(c >>> 1); } } crcTable[n] = c; } } var len:uint = 0; if (data != null) { len = data.length; } png.writeUnsignedInt(len); var p:uint = png.position; png.writeUnsignedInt(type); if ( data != null ) { png.writeBytes(data); } var e:uint = png.position; png.position = p; c = 0xffffffff; for (var i:int = 0; i < (e-p); i++) { c = uint(crcTable[ (c ^ png.readUnsignedByte()) & uint(0xff)] ^ uint(c >>> 8)); } c = uint(c^uint(0xffffffff)); png.position = e; png.writeUnsignedInt(c); } } }