I want to create a button that slowly fills up over time from an empty state to a full state. I imagine that what I’m trying to accomplish should be doable through an animated mask.

The blue State is when its empty, and as it fills up it turns green. I want the motion to be a “clock” like motion. But I really have no idea of how to get this going.

The parent is called Percent and that is the blue background. Its child is Green which is the green image, and text sits on top of it
Any thoughts?