<img src="http://i.imgur.com/5f9H1eH.png" border="0" />
Your app gets very poor performance though, you maybe implement a 128x128, 256x256 and 512x512-version of your rings on extra frames. Then for each ring check size.
If above 128x128 -> set to frame of the 256x256 variant
if above 256x256 -> set to frame of 512x512 variant
if above 512x512 -> set to frame of 2048x2048 variant
(note: i am not sure it will improve performance, but think it would)