as3 判断鼠标在非透明区域点击图片

1. /** 
2.                  *鼠标事件  
3.                  * @param evt 
4.                  *  
5.                  */                  
6.                   
7.                 private function mouseDownHandler(evt:MouseEvent):void  
8.                 {  
9.                          if(evt.currentTarget is SceneObject)  
10.                         {                  
11.                                 //判断当前点击区是否在最小图形范围内  
12.                                   
13.                                 var bmd:BitmapData = new BitmapData(evt.currentTarget.width,evt.currentTarget.height,true, 0x00000000);  
14.                                 bmd.draw(evt.currentTarget as SceneObject);  
15.                                                                    
16.                                                                 //第一种方法：找到对象的非空白区域，判断鼠标点击点是否在该区域内  
17.   
18.                                 ///看帮助 若要确定图像周围的空白区域，请传递 {mask: 0xFFFFFFFF, color: 0xFFFFFFFF} 以查找非空白像素的范围。如果new BitmapData时填充了 0x00000000则传递{mask: 0xFFFFFFFF, color: 0x00000000}  
19.                                 /*var rect:Rectangle = bmd.getColorBoundsRect(0xffffffff,0x00000000,false);         
20.                                 trace(rect); 
21.                                 var minx:Number =  rect.x; 
22.                                 var miny:Number =  rect.y; 
23.                                 var maxx:Number = minx + rect.width; 
24.                                 var maxy:Number = miny + rect.height; 
25.                                 */  
26.   
27.                                                                 //第二种方法 取当前点击点的颜色值 与0x0000000进行判断如果相等则非空白 ，  
28.                                 /*var color:uint = bmd.getPixel32(evt.localX,evt.localY); 
29.                                 trace(color.toString(16),0x00000000); //此处 的color值在点击透明区域输出0xffffffff 
30.                                 */  
31.   
32.                                                                  //第三种方法 利用像素碰撞函数hitTest一步解决 0x00000001 为取比0x00000000都大的区域都为非透明像素  
33.                                 var ptoint = new Point(evt.localX,evt.localY);   
34.                                 if(bmd.hitTest(new Point(0,0),0x00000001,pt))  
35.                                 //if(evt.localX>= minx  && evt.localX <= maxx && evt.localY  >= miny  && evt.localY <= maxy)  
36.                                 //if(color != 0x00000000)  
37.                                 {  
38.                                         trace("按下，在内部");  
39.                                                                                 bmd.dispose();  
40.                                 }  
41.                                 else  
42.                                 {  
43.                                         trace("按下，不在内部");  
44.                                         bmd.dispose();  
45.                                         return;//返回不停止事件流，让鼠标托动背景   
46.                                 }                        }  
47.                         evt.stopPropagation();  
48.                 }