Animate drawing the fill of a CAShapeLayer

I've been playing around with drawing a path using a CAShapeLayer as outlined in this great article, http://oleb.net/blog/2010/12/animating-drawing-of-cgpath-with-cashapelayer, but I'm wondering if there's a way to animate the filling of a layer.

For example, I have some text I want to draw on the screen, but I've only been able to draw the stroke of the text and not the fill. Another example, I have a star shape that I would like to animate it being filled in.

Is this possible using a CAShapeLayer or other object?

Thanks!