[ActionScript] AS3代码实现曝光过度效果

 package
 {
     import flash.display.Loader;
     import flash.display.SimpleButton;
     import flash.display.Sprite;
     import flash.events.Event;
     import flash.events.MouseEvent;
     import flash.geom.ColorTransform;
     import flash.net.URLRequest;

     /**
      * ...
      * @author FrostYen
      */
     public class ColorTransformExample extends Sprite
     {
         private var _ldr:Loader = new Loader();
         private var _sp:Sprite = new Sprite();
         private var _btn:Sprite = new Sprite();
         private var _colorTransform:ColorTransform = new ColorTransform(1, 1, 1, 1, 255, 255, 255, 0);
         private var _frame:int=15;//相当于影片剪辑动画的帧数
         public function ColorTransformExample() {

             _ldr.load(new URLRequest("image/farewell-to-fall.jpg"));
             _sp.transform.colorTransform = _colorTransform;

             _btn.graphics.beginFill(0x666666);
             _btn.graphics.drawRect(0, 0, 100, 50);
             _btn.graphics.endFill();
             _btn.buttonMode = true;
             _btn.x = 700;
             _btn.y = 100;

             this.addChild(_btn);
             this.addChild(_sp);
             _sp.addChild(_ldr);
             stage.frameRate = 36;//帧频

             _ldr.contentLoaderInfo.addEventListener(Event.COMPLETE, onImageLoaded);
             _btn.addEventListener(MouseEvent.CLICK, onClick);
         }

         private function onClick(e:MouseEvent):void
         {
             addEventListener(Event.ENTER_FRAME, onEnter);
         }

         private function onEnter(e:Event):void
         {
             if (_colorTransform.redOffset > 0) {
                 _colorTransform.redOffset -= 255/_frame;
                 _colorTransform.greenOffset -= 255/_frame;
                 _colorTransform.blueOffset -= 255/_frame;
                 _sp.transform.colorTransform = _colorTransform;
             }else {
                 _colorTransform = new ColorTransform(1, 1, 1, 1, 255, 255, 255, 0);
                 removeEventListener(Event.ENTER_FRAME, onEnter);
             }
         }

         private function onImageLoaded(e:Event):void
         {

         }
     }

 }