Flex 4 设置背景图片 Canvas backgroundImage BitmapFill fillMo

Flex 3中Canvas是可以设置backgroundImage的，但是在Flex 4的Spark组件中则不支持backgroundImage属性的设置，怎么办呢？方法当然很多：可以考虑用s:Group去代替Canvas，两个组件可以达到类似的功能，<s:Group width="100%"?height="111">??<s:Rect width="100%"?height="100%">??<s:fill>?<s:BitmapFill fillMode="scale"?source="@Embed(source='/assets/image/test.png')"/>??</s:fill>??</s:Rect>?<s:Button label="test"color="#FFFFFF"?left="10"?top="10"/>?</s:Group>?也可以在Canvas的外面用BorderContainer制造“假象”，?<s:BorderContainer backgroundImage="@Embed(source='/assets/image/test.png')"backgroundImageFillMode="scale"width="100%"borderVisible="false">??<mx:Canvas id="upPanel"width="100%"height="111"?horizontalScrollPolicy="off"?verticalScrollPolicy="off">??<s:Button label="test"?color="#FFFFFF"left="10"?top="10"/>??</mx:Canvas>??</s:BorderContainer>