AS3改变显示对象亮度

import flash.display.DisplayObject
import flash.geom.ColorTransform

//value取值范围-1~1,对应Flash内容制作工具里的-100%-100%
publicfunction setBrightness(obj:DisplayObject,value:Number):void {
    var colorTransformer:ColorTransform = obj.transform.colorTransform
    var backup_filters:* = obj.filters
if (value >= 0) {
        colorTransformer.blueMultiplier = 1-value
        colorTransformer.redMultiplier = 1-value
        colorTransformer.greenMultiplier = 1-value
        colorTransformer.redOffset = 255*value
        colorTransformer.greenOffset = 255*value
        colorTransformer.blueOffset = 255*value
    }else {
        value=Math.abs(value)
        colorTransformer.blueMultiplier = 1-value
        colorTransformer.redMultiplier = 1-value
        colorTransformer.greenMultiplier = 1-value
        colorTransformer.redOffset = 0
        colorTransformer.greenOffset = 0
        colorTransformer.blueOffset = 0
    }
　　obj.transform.colorTransform = colorTransformer
　　obj.filters = backup_filters
}