Flex改变颜色亮度

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" fontSize="16">
<mx:Button label="颜色亮度" click="button1_clickHandler(event)"/>
<mx:HBox id="box" width="200" height="200" backgroundColor="#003ed2"/>
<mx:Script><![CDATA[
import mx.utils.ColorUtil;
public var colorcount:int = 1;
private function button1_clickHandler(event:MouseEvent):void {
colorcount = colorcount+1;
box.setStyle("backgroundColor",ColorUtil.adjustBrightness(new uint('0x003ed2'),10*colorcount));

}
]]></mx:Script>
</mx:Application>