On Mon, Apr 26, 2010 at 1:46 PM, Jasper van de Gronde
In any case, you're definitely right that it would add complexity, and it is by no means meant as /the/ solution, but I do think we can and should consider some alternatives other than our way and the Illustrator way.
A simple and relatively cheap method, similar to your proposal, which I for some time was thinking of trying, would be to start by testing, from top to bottom, if any object in the repaint buffer covers it completely and has no opacity and filters; if yes, then discard objects below it and render only from this object up. However, to be of any use, this method must be used with our current buffered redraw, where the probability of an object to cover the entire strip buffer is significant. With the Illustrator method, this optimization would only work if some object covers the entire screen, which is much less probable.