dragon stop motion__or dragonframe
The G12 is not supported :-http://www.dragonframe.com/camera.php#powershot
As it says, the Canon SDK (software development kit) no longer supports Powershots.
If you mean can you do something similar with CHDK, the answer is yes.
You use something called PTP.
However, it does not run 'out-of-the-box', CHDK developers (especially G12 owners) can give you more information.
I have some software that will probably do what you want, if you get stuck contact me.