Flex 4 skin shape tween effect

I have two shapes in a skin:

1.Circ开发者_Go百科le

s:Ellipse width="20" height="20" includeIn="collapsed">

s:fill>

s:SolidColor color="#BBBBBB"/>

/s:fill>

/s:Ellipse>

2.Rectangle

s:Rect radiusX="10" radiusY="10" width="80" height="20" includeIn="expanded">

s:stroke>

s:SolidColorStroke color="0" weight="1"/>

/s:stroke>

s:fill>

s:SolidColor color="#00FF00"/>

/s:fill>

/s:Rect>

I want to have a shape tween. This kind of shape tween that is possible in Flash IDE. Circle needs to transform into rectangle smoothly. Is it possible in mxml ?

Only the Flash IDE can do it using the Timeline. You can't create it using code (unless you draw it manually), hence Flex doesn't support this feature.

However, I did find a Tweening library called Tweensy that says can do Vector Shape Tweens. It's in beta right now and I've never tried it, but it's worth a shot.