I should have mentioned that my tests have been done only on Windows and OSX.

I guess I would have to try on a system that supports XRender to compare. 

Unfortunately, the target audience of our application are mostly windows and OSX users, so although it would be great that Cairo performs fast on unix variants, it would be of little value to us, unless of course XRender also runs on Windows/OSX somehow :)

On Sat, Jan 31, 2009 at 8:54 PM, Duncan Coutts <duncan.coutts@worc.ox.ac.uk> wrote:
On Sat, 2009-01-31 at 13:18 +0100, Peter Verswyvelen wrote:
> When I said Cairo felt rather slow, I was comparing it again fully
> hardware accelerated solutions.
>
>
> With Cairo I am unable to perform full smooth screen redraws of even
> just a single solid rectangle, and when you are making ZUI (zoomable
> user interfaces), full screen redraws are not uncommon. "Smooth" here
> means at least 30 frames per second, but preferably 60 frames per
> second. It seems not the number of shapes that are rendered is the
> bottleneck, but the amount of pixels covered. At least that is what I
> noticed. I guess this is because it is a 100% software renderer, and
> it might have to perform per pixel conversion when copying to the
> video card, but I really don't know.

The X11 backend is accelerated if your X server supports it. It uses the
XRender extension. If you draw to an image surface then yes that is
software rendering. If you're happy to be connected to the X server then
you can still do off-screen drawing and again if your X server supports
it that can be accelerated too.

Some X servers accelerate some XRender operations and not others. I
think some of the gradient fills are problematic.

Duncan