Iris动画效果的代码

Iris.as

 

package  mx.effects ... {
    //导入Iris的实例类
    import mx.effects.effectClasses.IrisInstance;
    //扩展MastEffect
    public class Iris extends MaskEffect...{
        //包含flex的版本说明文件
            include "../core/Version.as";
        //构造函数
        public function Iris(target:Object = null)...{
            //调用父类的构造函数
            super(target);
            //指定实例类型
            instanceClass = IrisInstance;
        }
    }

}

IrisInstance.as

 

package  mx.effects.effectClasses ... {
    import mx.controls.SWFLoader;
     //扩展MastEffectInstance
    public class IrisInstance extends MaskEffectInstance...{
        //包含flex的版本说明文件          
        include "../../core/Version.as";
        //构造函数
        public function IrisInstance(target:Object)...{    
            super(target);
        }
        //覆盖父类的方法
        override protected function initMaskEffect():void...{
            //调用父类的同名方法
            super.initMaskEffect();
            //得到目标的实际尺寸，targetVisualBounds包含了目标可视区域的长和宽
            var targetWidth:Number = targetVisualBounds.width / Math.abs(target.scaleX);
            var targetHeight:Number = targetVisualBounds.height / Math.abs(target.scaleY);
            //如果目标是SWFLoader对象，则计算加载内容的尺寸，而不是目标本身的尺寸
            if (target is SWFLoader)...{
                targetWidth = target.contentWidth;
                targetHeight = target.contentHeight;        
            }
            //如果showTarget为true，表示显示目标对象
            if (showTarget)...{
                //定义x,y方向的起始放缩值
                scaleXFrom = 0;
                scaleYFrom = 0;
                scaleXTo = 1;
                scaleYTo = 1;
                //目标的起始位置
                xFrom = targetWidth / 2 + targetVisualBounds.x;
                yFrom = targetHeight / 2 + targetVisualBounds.y;
                //确定最后的坐标
                xTo = targetVisualBounds.x;
                yTo = targetVisualBounds.y;
            }else...{
                //如果是隐藏目标
                scaleXFrom = 1;
                scaleYFrom = 1;
                scaleXTo = 0;
                scaleYTo = 0;
                //目标的起始位置
                xFrom = targetVisualBounds.x;
                yFrom = targetVisualBounds.y;
                //确定最后的坐标
                xTo = targetWidth / 2 + targetVisualBounds.x;
                yTo = targetHeight / 2 + targetVisualBounds.y;
            }
    }
}

}