[Xorg-driver-geode] Rendering in geode

[Huang, FrankR]

Morton,

	We do need a complete description on the condition that the Source coordinates are outside the image. Because when I fixed this, another rendering issue in firefox is appearing with my patch. Some characters are missing in the rendering in firefox. It's not very to orientate the bug place, so can you provide me a good article to give a complete vision on these special conditions? That is very important for our driver's rendering work.

Thanks,
Frank

-----Original Message-----
From: Jonathan Morton [mailto:jonathan.morton at movial.com] 
Sent: 2010?6?21? 16:39
To: Matt Dew
Cc: Huang, FrankR; xorg-driver-geode at lists.x.org; xorg-devel at lists.x.org
Subject: Re: Rendering in geode

> > An unfortunate fact of EXA is that you need to throughly understand
> > XRender's requirements when implementing the Composite function.
> > This is fairly poorly documented.
> 
> What's missing exactly?

I think all of the necessary bits can be found in various places.  The
problem is that you have to know they're necessary and then go looking
for them.  The result is buggy drivers because of incomplete design,
entirely due to misunderstanding the specification requirements.

Normally one would like to read a reference implementation, but Pixman's
source code is extremely opaque and so it's very easy to miss things.

Also, the expected behaviour of the ModifyPixmapHeader hook is decidedly
unclear, particularly in the various corner cases that crop up in
practice.

-- 
------
From: Jonathan Morton
      jonathan.morton at movial.com