As3 操作图片，获取，设置实际像素，扣除透明区域

private var a:Loader = new Loader();
        private function test():void
        {
            a.load(new URLRequest("assets/冷却液管.png"));
            a.contentLoaderInfo.addEventListener(Event.COMPLETE, an);
        }
        private function an(evt:Event):void 
        {   
            var hh:BitmapData = new BitmapData(a.content.width,a.content.height,false,0xcccccc);
            var kk:Bitmap = new Bitmap(hh);
            addChild(kk);
            kk.x = 200;

            var tu2:Bitmap=Bitmap(a.content as Bitmap);
//            addChild(tu2);
            var yan:uint;
            for (var i:uint = 0; i<tu2.width; i++) 
            {
                for (var j:uint = 0; j<tu2.height; j++) 
                {
                    yan = (a.content as Bitmap).bitmapData. getPixel32 (i, j);
                    if (yan<=0)  // 要抠取的颜色 
                    {
//                        tu2.bitmapData. setPixel32 (i,j,0xffff0000);
                        hh. setPixel (i,j,0xff0000);
                    }
                }
            }   
        }