Circle Progress?

I've been looking into how to implement a circle progress and haven't had much luck. Ultimately, I concluded that the progress in the circle would have to be path and I would have to calculate the path to fill the circle. Does Ext have anything like

http://anthonyterrien.com/knob/

that we could use? Has anyone attempt or done this?

This article did a great job explaining how to draw sections of a pie. Using this method to fill my circle. Not sure if this is ideal, but this does work for me. Props to Stan Rogers for writing it.

http://www.codestore.net/store.nsf/unid/EPSD-5DTT4L