I needed to create an animated circular mask and some animated circles. I found progressBar.js, and it fit my needs well. I think this technique could trace any simple vector in a circular reveal. (according to the progressBar.js docs)
This is a similar problem to to Need help creating radial wipe mask
I didn’t see the VIVUS solution earlier. I haven’t tested the VIVUS version, so I’m not sure which is better.
My solution has significant overhead, to say the least… My target was a GIF, so overhead was less of a concern.