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); //如果bmd2透明度为0就能达到抠图的效果
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