Instead of disabling your app looping, try writing your own method to update your graphics and call that selectively from draw(). Then in draw(), all you otherwise need to do is not clear the current buffer. That way you'll still be able to perform other animations for things like user interface or a loading bar while calculating puzzles in the background.

A simple work-around.  Thanks!

I have the same question (except using regular OpenGL drawing, not Cairo)... Four years later, is this work-around still the only/best approach to only redraw when desired (e.g. on UI interaction)?  Or is there now a way to do this using signals -- requesting a redraw/repaint to later be drawn in the usual way?  Thanks!