加濾鏡效果GlowTween

/**
 *
 * new GlowTween(xxxx, 0xFFFF00);
 * new GlowTween(xxxx, 0x00FFFF);
 * GlowTween
 */

package com.riaidea.tween
{
    import flash.display.InteractiveObject;
    import flash.events.Event;
    import flash.events.MouseEvent;
    import flash.filters.GlowFilter;

    public class GlowTween
    {
        private var _target:InteractiveObject;
        private var _color:uint;
        private var _toggle:Boolean;
        private var _blur:Number;

        public function GlowTween(target:InteractiveObject, color:uint = 0xFFFFFF)
        {
            _target = target;
            _color = color;
            _toggle = true;
            _blur = 2;
            target.addEventListener(MouseEvent.ROLL_OVER, startGlowHandler);
            target.addEventListener(MouseEvent.ROLL_OUT, stopGlowHandler);
        }

        public function remove():void
        {
            _target.removeEventListener(MouseEvent.ROLL_OVER, startGlowHandler);
            _target.removeEventListener(MouseEvent.ROLL_OUT, stopGlowHandler);
            _target.removeEventListener(Event.ENTER_FRAME, blinkHandler);
            _target.filters = null;
            _target = null;
        }        

        private function startGlowHandler(evt:MouseEvent):void
        {
            _target.addEventListener(Event.ENTER_FRAME, blinkHandler, false, 0, true);
        }

        private function stopGlowHandler(evt:MouseEvent):void
        {
            _target.removeEventListener(Event.ENTER_FRAME, blinkHandler);
            _target.filters = null;
        }

        private function blinkHandler(evt:Event):void
        {
            if (_blur >= 20) _toggle = false;
            else if (_blur <= 2) _toggle = true;
            _toggle ? _blur++ : _blur--;
            var glow:GlowFilter = new GlowFilter(_color, 1, _blur, _blur, 2, 2);
            _target.filters = [glow];
        }
    }
}