[cairo] Profiling the slowness of xlib surface

Timothée Lecomte timothee.lecomte at ens.fr
Thu Apr 20 16:00:58 PDT 2006

> On Thu, 20 Apr 2006 20:11:47 +0200 (CEST), Timothée Lecomte wrote:
>> Regarding my problem with seams, SATURATE is the best solution, but it
>> implies using a termporary surface. Other solutions are not satisying,
>> as
>> far as I can tell (see previous threads about seams). So I guess I will
>> to
>> forget about xlib surfaces.
> I think SATURATE is a good solution for what you are doing. I hope you
> don't abandon xlib surfaces completely. Or rather, if you need to,
> please do it consciously as an interim solution---that is continue to
> make the xlib paths available so that the people working on fixing the
> bugs, (both correctness and performance), can do so, and that you can
> verify the improvement.

Don't worry, I will let the code in place, I will just disable it for a

On the other hand, I am glad to see that the win32 surface implementation
works well. I also had a chance to try the glitz, and it was at least

>> Can this mean that each time I call cairo_fill(), for example, the
>> server
>> copies the pixmap to main memory to render through pixman and then
>> copies
>> it back to video memory ? In that case, that would make thousands of
>> copies back and forth for the whole rendering. I hope I am wrong !
> Or you can hope you are right... That is, the more brain-damaged the
> performance bugs are, the easier they are to fix, and the more
> improvement that results. ;-)

Well, if you or somebody else is willing to give pointers to what could be
done to improve that aspect, I would be glad to see if I can help.

> I do wish all of this stuff were done already and you would just be
> pleased as punch with blistering performance from cairo, but I hope
> you won't have to walk away displeased. There are lots of good things
> coming I believe.

I really appreciate the way you see the work that you and others do on
Cairo. Be sure that I am pleased to use it, and I will probably be even
more pleased in the future !

Best regards,


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