Flex : Draw ellipse on Image?

I have an Image object and I wish to 开发者_StackOverflow社区draw an ellipse on it.

I have tried with:

imageObj.graphics.beginFill( 0x0000FF, 0.5 );
imageObj.graphics.drawEllipse( position.x, position.y, 10, 10 );
imageObj.graphics.endFill();

However, it doesn't draw anything at all.

How can I draw a graphic primitive on an Image object?

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You cannot draw elipse directly on a image, you need to draw on a UIComponent.

The following link may help you:

http://groups.google.com/group/macromedia.flex.flex_builder/browse_thread/thread/bbcfc4e3e0a2e133

http://www.axelscript.com/2008/06/11/drawing-in-flex-using-the-uicomponent/