Image Mask - Scaling/Key Framing?

I'm trying to keyframe and scale an image mask in FCPX, but all I see are offset options - the actual mask effect has no options for scaling etc. Is there a way around this I'm not seeing?

Thanks,

Yes, it is called TrackX from Coremelt.

Does it need to be an image mask? What exactly are you trying to achieve? Could it be done by using 'draw mask' instead? There are transform controls with draw mask.

But are you trying to track it to something? If so, it is possible to do it manually, but waaaaay easier and faster with something like TrackX as Ben mentioned.

Im not on the latest version of FCP and haven't played with the new tracking features. Ben Basler, do you think the new tracking features will eventually replace the need for something like TrackX?

The new tracking feature doesn't track masks, so yes, TrackX and SliceX are still needed. And to correct myself, SliceX is what the OP really needs.