自定义Slider，滑块变形的问题

var _lifeSlider:GSlider = new GSlider();//设置滑块大小。由于默认滑块大小为13X13的。若想设置的滑块小于默认的时，会被拉大。var thumbSprite:Sprite = new Sprite();var thumb:Bitmap = GlobalClass.getBitmap("ControlBarBig");thumbSprite.graphics.beginFill(0xFFFFFF, 0);thumbSprite.graphics.drawRect(0,0,13,13);thumbSprite.addChild(thumb);_lifeSlider.setStyle("sliderTrackSkin",new Bitmap());_lifeSlider.setStyle("sliderTrackDisabledSkin",new Bitmap());_lifeSlider.setStyle("thumbDisabledSkin",thumbSprite);_lifeSlider.setStyle("thumbDownSkin",thumbSprite);_lifeSlider.setStyle("thumbOverSkin",thumbSprite);_lifeSlider.setStyle("thumbUpSkin",thumbSprite);_lifeSlider.width = 100;_lifeSlider.height = 10;_lifeSlider.maximum = 100;_lifeSlider.minimum = 1;_lifeSlider.value = 50;_lifeSlider.snapInterval = 1;_lifeSlider.liveDragging = true;_lifeSlider.addEventListener(SliderEvent.CHANGE, onLifeSetChangeHandler);this.addChild(_lifeSlider);