Doubt about render implementation: CompositePicture

[Adam Jackson]

On Thursday 25 May 2006 15:47, Carlos Eduardo Rodrigues Diógenes wrote:
> Hi,
>
> When the CompositePicture is called in xrender it's call
> (*ps->Composite), but this is a pointer to function, isn't is? I don't
> find the place where the function address is puted in this pointer. I
> don't find any attribution to the pointers to function declared in
> _PictureScreen struct.

fb/fbpict.c:    ps->Composite = fbComposite;

fb implements the fallback case.  Higher layers are allowed to "wrap" function 
calls, which is basically how you do message delegation in C - hooray for 
procedural languages - and is how we implement acceleration, among other 
things.  Currently the exa, xaa, rootless, and shadowfb layers wrap the 
->Composite dispatch chain, as well as several of the kdrive servers.

Wrapping is probably the most difficult convention in the X server source to 
understand, so if you have more questions please do ask.

- ajax
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
URL: <http://lists.x.org/archives/xorg/attachments/20060525/f0e77a77/attachment.pgp>