AS3通过PNGEncoder类将图片与ByteArray互换实例
as3中图片转换成ByteArray再由ByteArray转换成图片的过程。
其中是调用Abode官方的类 PNGEncoder来实现的。但是之前总是报错,具体如下:
var encoder:PNGEncoder = new PNGEncoder();
然后var bytes:ByteArray=encoder.encode(_bmd);
调用encode这个方法
结果报错 1061: 调用可能未定义的方法 encode (通过 static 类型 PNGEncoder 引用)。
后来我才发现,需要将var encoder:PNGEncoder = new PNGEncoder();
然后var bytes:ByteArray=encoder.encode(_bmd); 这两句改成
var bytes:ByteArray=PNGEncoder.encode(_bmd); 因为encode为静态函数。
好啦,下面把源码贴上:
首先为 Abode官方的类 PNGEncoder
- package
- {
- import flash.geom.*;
- import flash.display.Bitmap;
- import flash.display.BitmapData;
- import flash.utils.ByteArray;
- public class PNGEncoder
- {
- 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);
- }
- }
- }
然后,在as3文件中调用,将图片转换成ByteArray:
- package
- {
- import flash.events.Event;
- import flash.net.URLRequest;
- import flash.display.Loader;
- import flash.events.IOErrorEvent;
- import flash.display.Bitmap;
- import flash.display.BitmapData;
- import flash.display.Sprite;
- import flash.display.MovieClip;
- import flash.utils.ByteArray;
- //import mx.utils.Base64Decoder;
- public class main extends MovieClip
- {
- private var imgLoader:Loader= new Loader();;
- private var arr:Array;
- private var _bmd:BitmapData;
- public function main()
- {
- imgLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, onIMGComplete);
- imgLoader.contentLoaderInfo.addEventListener(IOErrorEvent.IO_ERROR, onError);
- imgLoader.load(new URLRequest("1.jpg"));
- arr=[];
- }
- private function onIMGComplete(evt:Event):void
- {
- var _bitmap:Bitmap=evt.target.content;
- _bmd=_bitmap.bitmapData.clone();
- imgLoader.unload ();
- var bytes:ByteArray=PNGEncoder.encode(_bmd);//转化为二进制数据
- }
- private function onError(evt:Event):void
- {
- trace('出错了!');
- }
- }
- }
- 如果需要将ByteArray再转换成图片,代码如下:
- package
- {
- import flash.events.Event;
- import flash.net.URLRequest;
- import flash.display.Loader;
- import flash.events.IOErrorEvent;
- import flash.display.Bitmap;
- import flash.display.BitmapData;
- import flash.display.Sprite;
- import flash.display.MovieClip;
- import flash.utils.ByteArray;
- public class main extends MovieClip
- {
- private var imgLoader:Loader= new Loader();;
- private var arr:Array;
- private var _bmd:BitmapData;
- public function main()
- {
- imgLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, onIMGComplete);
- imgLoader.contentLoaderInfo.addEventListener(IOErrorEvent.IO_ERROR, onError);
- imgLoader.load(new URLRequest("1.jpg"));
- arr=[];
- }
- private function onIMGComplete(evt:Event):void
- {
- var _bitmap:Bitmap=evt.target.content;
- _bmd=_bitmap.bitmapData.clone();
- imgLoader.unload ();
- var bytes:ByteArray=PNGEncoder.encode(_bmd);//转化为二进制数据
- trace(bytes[0]);
- var load:Loader=new Loader();
- load.loadBytes(bytes);//读取ByteArray
- load.contentLoaderInfo.addEventListener(Event.COMPLETE, complete);
- }
- private function complete(event:Event):void {
- var bitMap:Bitmap=event.target.content as Bitmap;//读取Bitmap
- addChild(bitMap); }
- private function onError(evt:Event):void
- {
- trace('出错了!');
- }
- }
- }