As3.0中的位图(Bitmap/BitmapData)编程

As3.0中的位图(Bitmap/BitmapData)编程功能十分丰富，下面这些是官方文档上的基本示例：

1.位图使用(模糊)滤镜

//创建一个矩形区域的BitmapData
var bmd:BitmapData = new BitmapData(80, 30, false, 0xefefef);
 
//画个红色的矩形
var rect:Rectangle = new Rectangle(20, 10, 40, 10);
bmd.fillRect(rect, 0xFF0000);
 
//找到红色矩形的右上顶点
var pt:Point = new Point(rect.left, rect.top);
 
//定义一个模糊滤镜
var filter:BlurFilter = new BlurFilter(8,8,1);
 
//应用滤镜
bmd.applyFilter(bmd, rect, pt, filter);
 
//创建一个位图对象，并加入到舞台
var bm:Bitmap = new Bitmap(bmd);
 
bm.scaleX = bm.scaleY = 2.0;
bm.x = stage.stageWidth/2 -bm.width/2;
bm.y = stage.stageHeight/2 - bm.height/2 ;
 
addChild(bm);

2.像素拷贝及赋值

var bmd1:BitmapData = new BitmapData(90, 60, false, 0x00000000);
var bmd2:BitmapData = bmd1.clone();//拷贝
 
//"画"一条白色的线
for(var i:uint=10;i<=40;i++){
    bmd1.setPixel32(i, i, 0xFFFFFFFF);
}
 
trace(bmd1.getPixel32(10, 10).toString(16)); // ffffffff
trace(bmd2.getPixel32(10, 10).toString(16)); // ff000000
 
var bm1:Bitmap = new Bitmap(bmd1);
this.addChild(bm1);
bm1.x =bm1.y = 5;
 
var bm2:Bitmap = new Bitmap(bmd2);
bm2.x = 105;
bm2.y =5;
this.addChild(bm2);

3.颜色变换

var bmd:BitmapData = new BitmapData(80, 30, false, 0xFF0000);
 
var cTransform:ColorTransform = new ColorTransform();
cTransform.alphaMultiplier = 0.8;//设置透明度因子为0.8
var rect:Rectangle = new Rectangle(0, 0, 40, 30);//定义左半边矩形区域
bmd.colorTransform(rect, cTransform);//对rect区域应用colorTransform
 
var bm:Bitmap = new Bitmap(bmd);
addChild(bm);
 
bm.x = stage.stageWidth/2 - bm.width/2;
bm.y = stage.stageHeight/2 - bm.height/2;

4.比较位图差异

var bmd1:BitmapData = new BitmapData(50, 50, true, 0xFFFFAA00);
var bmd2:BitmapData = new BitmapData(50, 50, true, 0xCCFFAA00);
var diffBmpData:BitmapData = BitmapData(bmd1.compare(bmd2));
var diffValue:String = diffBmpData.getPixel32(1, 1).toString(16);
//解释：当二个位置尺寸大小相同，且仅alpha分量不同时，compare的值为 zzFFFFFF，其中zz为bmd1与bmd2的alpha分量差
trace (diffValue); // 33ffffff
 
var bm1:Bitmap = new Bitmap(bmd1);
addChild(bm1);
bm1.x = bm1.y = 5;
var bm2:Bitmap = new Bitmap(bmd2);
addChild(bm2);
bm2.x = 60;
bm2.y = 5;
 
var bmDiff = new Bitmap(diffBmpData);
addChild(bmDiff);
bmDiff.x = 115;
bmDiff.y = 5;

var bmd1:BitmapData = new BitmapData(50, 50, true, 0xFF00FF99);
var bmd2:BitmapData = new BitmapData(50, 50, true, 0x99AA3366);
var diffBmpData:BitmapData = BitmapData(bmd1.compare(bmd2));
var diffValue:String = diffBmpData.getPixel32(1, 1).toString(16);
//解释：当二个位置尺寸大小相同，但RGB分量不同时，compare的值为 FFxxyyzz，其中xx,yy,zz分别为bm1与bm2的RGB分量差，同时alpha分量差将被忽略
trace (diffValue); // ff56cc33
 
var bm1:Bitmap = new Bitmap(bmd1);
addChild(bm1);
bm1.x = bm1.y = 5;
var bm2:Bitmap = new Bitmap(bmd2);
addChild(bm2);
bm2.x = 60;
bm2.y = 5;
 
var bmDiff = new Bitmap(diffBmpData);
addChild(bmDiff);
bmDiff.x = 115;
bmDiff.y = 5;

5.拷贝颜色通道

var bmd:BitmapData = new BitmapData(stage.stageWidth, stage.stageHeight, false, 0x00FF0000);
 
var rect:Rectangle = new Rectangle(0, 0, 20, 40);
var pt:Point = new Point(10, 10);
bmd.copyChannel(bmd, rect, pt, BitmapDataChannel.RED, BitmapDataChannel.BLUE);//将红色通道复制到以(10,10)为顶点，宽为20,高为40的矩形区域的蓝色通道中
 
trace(bmd.getPixel32(10,10).toString(16));//ffff00ff，即矩形区域的最终颜色值为ff ff 00 ff(纯红 叠加 纯蓝)
 
var bm:Bitmap = new Bitmap(bmd);
this.addChild(bm);

6.截取位图的某一部分(像素)

var bmd1:BitmapData = new BitmapData(40, 40, false, 0x000000FF);
var bmd2:BitmapData = new BitmapData(80, 40, false, 0x0000CC44);
 
var rect:Rectangle = new Rectangle(0, 0, 20, 20);
var pt:Point = new Point(10, 10);
bmd2.copyPixels(bmd1, rect, pt);//将bmd1中以pt为左上顶点的rect矩形像素复制到bmd2中
 
var bm1:Bitmap = new Bitmap(bmd1);
this.addChild(bm1);
var bm2:Bitmap = new Bitmap(bmd2);
this.addChild(bm2);
bm2.x = 50;

7.将文本转换为位图

import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.text.TextField;
 
var tf:TextField = new TextField();
tf.text = "bitmap text";
 
var myBitmapData:BitmapData = new BitmapData(80, 20);
myBitmapData.draw(tf);
var bmp:Bitmap = new Bitmap(myBitmapData);
this.addChild(bmp);
bmp.x = stage.stageWidth/2 - bmp.width/2;
bmp.y = stage.stageHeight/2 - bmp.height/2;

8.仿PS中的颜色填充工具

//准备一个40*40绿色背景的BitmapData
var myBitmapData:BitmapData = new BitmapData(40, 40, false, 0x0000FF00);
 
//画二个有“交叉重叠”部分的“蓝色”矩形
var rect:Rectangle = new Rectangle(0, 0, 25, 25);
myBitmapData.fillRect(rect, 0x000000FF);
rect = new Rectangle(20, 20, 20, 20);
myBitmapData.fillRect(rect, 0x000000FF);
 
//从坐标(10,10)开始寻找与(10,10)坐标(像素点相同且连续的区域)填充红色
myBitmapData.floodFill(10, 10, 0x00FF0000);
 
var bm:Bitmap = new Bitmap(myBitmapData);
addChild(bm);
 
bm.scaleX  = bm.scaleY = 3.0;
bm.x = stage.stageWidth/2 - bm.width/2;
bm.y = stage.stageHeight/2 - bm.height/2;

9.颜色融合

import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.geom.Rectangle;
import flash.geom.Point;
 
var bmd1:BitmapData = new BitmapData(100, 80, true, 0xFF00FF00);
var bmd2:BitmapData = new BitmapData(100, 80, true, 0xFFFF0000);
var rect:Rectangle = new Rectangle(0, 0, 40, 40);
var pt:Point = new Point(20, 20);
var mult:uint = 0x80; // 50% ,各通道值均为128，即50%
bmd1.merge(bmd2, rect, pt, mult, mult, mult, mult);
 
var bm1:Bitmap = new Bitmap(bmd1);
addChild(bm1);
var bm2:Bitmap = new Bitmap(bmd2);
addChild(bm2);
bm2.x = 110;
 
//最终值
//new redDest = [(redSrc * redMultiplier) + (redDest * (256 - redMultiplier))] / 256;
trace(bmd1.getPixel32(20,20).toString(16)); //ff7f7f00
 
//解释:
//返回值中Red分量为 7f = 0x00 * 0x80 + 0xff*(0x100-0x80)/0x100

10.噪点图

var bmd1:BitmapData = new BitmapData(80, 80);
var bmd2:BitmapData = new BitmapData(80, 80);
 
var seed:int = int(Math.random() * int.MAX_VALUE);
bmd1.noise(seed, 0, 0xFF, BitmapDataChannel.RED, false);
bmd2.noise(seed, 0, 0xFF, BitmapDataChannel.RED, true);
 
var bm1:Bitmap = new Bitmap(bmd1);
this.addChild(bm1);
bm1.x = 10;
bm1.y = 10;
var bm2:Bitmap = new Bitmap(bmd2);
this.addChild(bm2);
bm2.x = 100;
bm2.y = 10;
 
 
stage.addEventListener(Event.ENTER_FRAME,enterFrameHandler);
 
function enterFrameHandler(e:Event):void{
    seed = Math.floor(Math.random() * int.MAX_VALUE);
    bmd1.noise(seed, 0, 0xFF, BitmapDataChannel.RED, false);
    bmd2.noise(seed, 0, 0xFF, BitmapDataChannel.RED, true);
    bm1.bitmapData = bmd1;
    bm2.bitmapData = bmd2;
}

11.另一种噪点图(有点类似卫星云图)

import flash.display.Bitmap;
import flash.display.BitmapData;
 
var bmd:BitmapData = new BitmapData(200, 200, false, 0x00CCCCCC);
 
var seed:Number = Math.floor(Math.random() * 999999);
var channels:uint = BitmapDataChannel.GREEN | BitmapDataChannel.BLUE;
bmd.perlinNoise(100, 80, 6, seed, false, true, channels, false, null);
 
var bm:Bitmap = new Bitmap(bmd);
addChild(bm);
bm.x = stage.stageWidth/2 - bm.width/2;
bm.y = stage.stageHeight/2 - bm.height/2;
 
stage.addEventListener(Event.ENTER_FRAME,enterFrameHandler);
 
function enterFrameHandler(e:Event):void{
    seed = Math.floor(Math.random() * 999999);
    bmd.perlinNoise(100, 80, 6, seed, false, true, channels, false, null);
    bm.bitmapData = bmd;    
}

12.像素融解

import flash.display.BitmapData;
import flash.display.Bitmap;
import flash.geom.Point;
import flash.geom.Rectangle;
import flash.utils.Timer;
import flash.events.TimerEvent;
 
var rndColor:int = Math.random() * 0xffffffff;//随机背景色
var fillColor:int = Math.random() * 0xffffffff;//随机填充色
 
var bmd:BitmapData = new BitmapData(100, 100, false, rndColor);
var bitmap:Bitmap = new Bitmap(bmd);
addChild(bitmap);
 
bitmap.scaleX = bitmap.scaleY = 1.5;
bitmap.x = stage.stageWidth/2 - bitmap.width/2;
bitmap.y = stage.stageHeight/2 - bitmap.height/2;
 
var tim:Timer = new Timer(20);
tim.start();
tim.addEventListener(TimerEvent.TIMER, timerHandler);
  
function timerHandler(event:TimerEvent):void {
    var randomNum:Number = Math.floor(Math.random() * int.MAX_VALUE);
    dissolve(randomNum);
}
 
function dissolve(randomNum:Number):void {
    var rect:Rectangle = bmd.rect;
    var pt:Point = new Point(0, 0);
    var numberOfPixels:uint = 100;//每次融解100个像素    
    bmd.pixelDissolve(bmd, rect, pt, randomNum, numberOfPixels, fillColor);
    var grayRegion:Rectangle = bmd.getColorBoundsRect(0xFFFFFFFF, rndColor, true);
     
    if(grayRegion.width == 0 && grayRegion.height == 0 ) {
        bmd.dispose();
        rndColor = Math.random() * 0xffffffff;
        fillColor = Math.random() * 0xffffff;
        bmd = new BitmapData(100, 100, false, rndColor);
        bitmap.bitmapData = bmd;
         
        //tim.stop();
    }
}

13.查找满足条件的颜色并替换

import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.display.BitmapDataChannel;
import flash.geom.Point;
import flash.geom.Rectangle;
 
var bmd1:BitmapData = new BitmapData(200, 200, true, 0xFFCCCCCC);
 
var seed:int = int(Math.random() * int.MAX_VALUE);
var channels:uint = BitmapDataChannel.RED | BitmapDataChannel.BLUE;
bmd1.perlinNoise(100, 80, 12, seed, false, true, channels, false, null);
 
var bitmap1:Bitmap = new Bitmap(bmd1);
addChild(bitmap1);
 
var bmd2:BitmapData = new BitmapData(200, 200, true, 0xFFCCCCCC);
var pt:Point = new Point(0, 0);
var rect:Rectangle = new Rectangle(0, 0, 200, 200);
var threshold:uint =  0x00800000;//50%的红色通道值 
var color:uint = 0x80FF0000;//替换后的颜色
var maskColor:uint = 0x00FF0000;//因为只查找红色通道，所以遮罩仅为纯红色通道
bmd2.threshold(bmd1, rect, pt, ">", threshold, color, maskColor, true);
 
var bitmap2:Bitmap = new Bitmap(bmd2);
bitmap2.x = bitmap1.x + bitmap1.width + 10;
addChild(bitmap2);
 
addEventListener(Event.ENTER_FRAME,EnterFrameHandler);
 
function EnterFrameHandler(e:Event):void{
    seed = int(Math.random() * int.MAX_VALUE);
    bmd1.perlinNoise(100, 80, 12, seed, false, true, channels, false, null);
    bitmap1.bitmapData = bmd1;
    bmd2.threshold(bmd1, rect, pt, ">", threshold, color, maskColor, true);
    bitmap2.bitmapData = bmd2;
}

14.综合应用1：模仿MetaBall(当然这种方法并不精确)

var ballNum:uint=5;
var balls:Array = new Array();
var sW:Number=stage.stageWidth;
var sH:Number=stage.stageHeight;
var container:Sprite = new Sprite();
var bmd:BitmapData=new BitmapData(sW,sH,false,0x00000000);
var bitmap:Bitmap;
var i:uint=0;
var rect:Rectangle=new Rectangle(0,0,sW,sH);
var pt:Point=new Point(0,0);
var filter:BlurFilter=new BlurFilter(15,15);
 
function init() {
    for (i=0; i=sW-b.radius-adjust) {
            b.x=sW-b.radius-adjust;
            b.vx*=-1;
        } else if (b.x=sH-b.radius-adjust) {
            b.y=sH-b.radius-adjust;
            b.vy*=-1;
        } else if (b.y

15.综合应用2-粒子效果(从 天地会 淘来的)

package asbook
{
    import flash.display.*
    import flash.geom.*
    public class particleSample extends Sprite 
    {
        private var apoint : Point;
        private var aspeed : Number = 0;
        private var arote  : Number = 0;
        private var cpoint : Point;
        private var rl : Number = 0;
         
        public function particleSample(cp:Point , lg:Number , art:Number , asp:Number):void
        {// 1s
            apoint = new Point();
            cpoint = cp;
            rl = lg;
            arote = art;
            aspeed = asp;
            setapoint();
        }// 1e
         
        public function pmove():Point 
        {// 2s
            arote += aspeed;
            if(arote >= 360) arote -= 360;
            setapoint();
            return apoint;
        }// 2e
         
        public function setapoint():void
        {// 3s
            var temp:Number = arote * Math.PI / 180;
            apoint.x = cpoint.x + rl * Math.cos(temp);
            apoint.y = cpoint.y + rl * Math.sin(temp);
             
        }// 3e
    }// class end
}// package end

package asbook{
    import flash.events.*;
    import flash.display.*;
    import flash.text.*;
    import flash.utils.*;
    public class FPSshow extends Sprite {
        private var FPStxt:TextField;
        private var FPScount:Number;
        private var FPStimer:int;
        private var fm:TextFormat;
        public function FPSshow() {
            fm = new TextFormat();
            fm.size  = 20;
            FPStxt = new TextField();
            FPStxt.defaultTextFormat = fm;
            FPScount = 0;
            FPStxt.textColor = 0xFFFFFF;
            FPStxt.x = 10;
            FPStxt.y = 10;
            addEventListener(Event.ADDED , onadd);
            addEventListener(Event.REMOVED  , onremove);
 
        }
        private function onadd(evt:Event) {
            stage.addEventListener(Event.ENTER_FRAME  , showFPS);
            addChild(FPStxt);
            FPStimer = getTimer();
        }
        private function onremove(evt:Event) {
            stage.removeEventListener(Event.ENTER_FRAME , showFPS);
        }
        private function showFPS(evt:Event ) {
            if ( getTimer() - 1000 > FPStimer ) {
                FPStimer = getTimer();
                FPStxt.text = "FPS : "+FPScount;
                FPScount = 0;
            } else {
                FPScount++;
            }
        }
 
    }//end class
}//end package

package asbook{
    import asbook.particleSample;
    import asbook.FPSshow;
    import flash.filters.*;
    import flash.display.*;
    import flash.geom.*;
    import flash.events.*;
     
    [SWF(height="300",width="300",frameRate=100)]
    public class main extends MovieClip {
        private var gNum1:int=1500;
        private var gNum2:int=1500;
        private var gArr:Array=[];
        private var ccPoint:Point;
        private var rrl:Number;
        private var length1:Number=50;
        private var length2:Number=200;
        private var length3:Number=300;
        private var bmp:Bitmap;
        private var bmd:BitmapData;
        private var bmdctf:ColorTransform=new ColorTransform(0.96,0.86,0);
        private var stgw:Number=stage.stageWidth;
        private var stgh:Number=stage.stageHeight;
        private var started:Boolean=false;
        private var bmped:Boolean=false;
 
        public function main() {
            ccPoint=new Point(stgw/2,stgh/2);
            initbmp();
            initstart();
            addEventListener(Event.ENTER_FRAME , run);
            addChild( new FPSshow()  );
        }
 
 
        private function initbmp():void {
            if (bmped) {
                return;
            }
            bmped=true;
            bmd=new BitmapData(stgw,stgh,false,0);
            bmp=new Bitmap(bmd);
            addChild(bmp);
        }
 
        private function initstart():void {
            if (started) {
                return;
            }
            started=true;
 
            for (var i:int  = 1; i <= gNum1; i++) {
                rrl=Math.abs(Math.random()-Math.random());
                var pp:particleSample = new particleSample(ccPoint , rrl * ( (length2 - length1)  / 2  *  1.2 )  + length1 / 2  , Math.random() * 360 , Math.random() * 10 - 6 );
                gArr.push(pp);
            }
 
            for (i  = 1; i <= gNum2; i++) {
                rrl=Math.abs(Math.random()-Math.random());
                var pp:particleSample = new particleSample(ccPoint , rrl *  (length3 - length2) / 2      + length2 / 2  , Math.random() * 360 , Math.random() * 5 - 3 );
                gArr.push(pp);
            }
            trace("Total:  " + gArr.length);
        }
        private function run(evt:Event):void {
            bmd.lock();
            bmd.colorTransform(bmd.rect , bmdctf);
            bmd.applyFilter(bmd , bmd.rect , new Point() , new BlurFilter(10 , 10 ,1));
            var pppoint:Point = new Point();
            for (var i:int = 0; i <=( gArr.length - 1 ); i++) {
                var pptemp:particleSample=gArr[i] as particleSample;
                pppoint=pptemp.pmove();
                bmd.setPixel32(pppoint.x , pppoint.y , 0xffffff);
            }
            bmd.unlock();
        }
    }// main class end
}//package end