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);