Actionscript 3 在AS3中创建带有阴影的文本

我试图在ActionScript3.0中创建一个带有阴影的简单文本；例如：

_tf = new TextField();
_tf.autoSize = TextFieldAutoSize.CENTER;
_tf.selectable = false;
var format:TextFormat = new TextFormat();
format.font = "Arial";
format.bold = true;
format.color = 0xffffff;
format.size = 12;
_tf.text = "Drop shadow";
_tf.defaultTextFormat = format;
addChild(_tf);

我怎样才能得到这篇有阴影的文章？？？

甚至更好

_tf.filters = [new DropShadowFilter()];

_tf.filters = [filter(4,153,0xffffff,0.7,4,4,0.7,0.15,false,false,false)];

function filter(distance, angle, color, alpha, blurX, blurY, strength, quality, inner, knockout, hideObject){
    return new DropShadowFilter(distance, angle, color, alpha, blurX, blurY, strength, quality, inner, knockout, hideObject);
}

其他方式：

_tf.filters = [new DropShadowFilter(4.0,45,0x000000,1.0,4.0,4.0,1.0,1,false,true,false)];
/*
DropShadowFilter(distance:Number = 4.0, angle:Number = 45, color:uint = 0, alpha:Number = 1.0, blurX:Number = 4.0, blurY:Number = 4.0, strength:Number = 1.0, quality:int = 1, inner:Boolean = false, knockout:Boolean = false, hideObject:Boolean = false);

DropShadowFilter
distance:Number = 4.0
angle:Number = 45
color:uint = 0
alpha:Number = 1.0
blurX:Number = 4.0
blurY:Number = 4.0
strength:Number = 1.0
quality:int = 1
inner:Boolean = false
knockout:Boolean = false
hideObject:Boolean = false
*/

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此处的文档：

我如何给出调整阴影的参数？请在此处查找DropShadowFilter（）的构造函数参数：