[Xcb] libXrender port to XCB

[Vincent Torri]

> Beware: the code I committed is entirely untested (though I made sure it
> compiles) and the cache functions (XCBRenderUtilQueryVersion and
> XCBRenderUtilQueryFormats) won't work until Plan 7 is implemented.

ok, it will be tested :)

> On the other hand, that means we now have an example of code that can
> make good use of Plan 7:
> 	http://gitweb.freedesktop.org/?p=xcb;a=blob;hb=HEAD;f=xcb-util/renderutil/cache.c
> The equivalent code in libXrender has a comment that says, "I suspect
> this is not really thread safe, but Xlib doesn't provide a lot of
> options here":
> 	http://cvsweb.freedesktop.org/xorg/lib/Xrender/src/Xrender.c?rev=HEAD&view=markup
> ... Yay us. :-)

we want the Plan 7 !! We all want it !

> > thank you for these utility functions. I'll use them in the xrender xcb
> > engine of evas. It will remove some code, as i've coded them for the
> > engine :-)
>
> Yeah, I wanted to kill the similar code I put into Cairo. Someone added
> a comment there:
>
> /* XXX: Why is this ridiculously complex compared to the equivalent
>  * function in cairo-xlib-surface.c */
>
> :-)

did he ever looked at the Xlib code of these functions ? ;-)

> > May I ask you to look at the xrender functions that draw a polygon too ?
> > :-D The engine needs them too, and i've not written them :-D
>
> You may ask, but following Keith's advice I intentionally left
> XRenderCompositeDoublePoly out of my port:
> 	http://lists.freedesktop.org/archives/xcb/2006-February/001318.html

:) yeah, I remember that mail

> I don't know what to suggest for you though. Probably you should get
> raster to read whatever papers Carl and Keith have been reading about
> tesselating polygons, and convince him to replace the call to
> XRenderCompositeDoublePoly with something more appropriate. You can
> point out the memory allocation, sorting, and computation overhead of
> the current code if it helps any. :-)

ok. Thank you

Vincent