[AS3][倒影算法][转载]

效果如图:

function createRef(picSource:DisplayObject):void{
    // 倒置
    var bd:BitmapData = new BitmapData(picSource.width,picSource.height,true,0x12346f);
    var mtx:Matrix = new Matrix();
    mtx.d = -1;
    mtx.ty = bd.height;
    bd.draw(picSource,mtx);    
    // 添加渐变遮罩
    var int = bd.width;
    var height:int = bd.height;
    mtx = new Matrix();
    mtx.createGradientBox(width,height,0.5 * Math.PI);
    var shape:Shape = new Shape();
    shape.graphics.beginGradientFill(GradientType.LINEAR ,[0,0],[0.9,0.2],[0,0xFF],mtx);

    shape.graphics.drawRect(0,0,width,height);
    shape.graphics.endFill();
    var mask_bd:BitmapData = new BitmapData(width,height,true,0);
    mask_bd.draw(shape);
    // 生成最终效果
     bd.copyPixels(bd,bd.rect,new Point(0,0),mask_bd,new Point(0,0),false); 
    // 将倒影放置于图片下方
    var ref:Bitmap=new Bitmap(); 
    ref.y=picSource.height + picSource.y; 
    ref.x = picSource.x;
    ref.bitmapData=bd; 
    picSource.parent.addChild(ref); 
    }