AS 3表示対象の明るさを変えるコードとは

 ， 《ActionScript 3.0 Cookbook》 ， Flash ， ， ， 

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

//value -1~1, Flash -100%-100%
public function 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
}

 ，colorTransformer