Finishing Composite to handle transformed windows

[Allen Akin]

On Mon, Jan 09, 2006 at 05:21:59PM -0800, Keith Packard wrote:
| ... I'm wondering if we can't use some other method, while retaining the
| option of using just the visual ...

Perhaps FBConfigs can be pressed into service.  FBConfigs are already
independent of Visuals to some extent, because FBConfigs can apply to
drawing surfaces which don't have Visuals.  I took a quick look through
the GLX spec and didn't see any requirement that there be a one-to-one
mapping between FBConfigs for windows and Visuals (although the language
clearly leans in that direction).  Relaxing any implied requirement of
that sort might be a feasible change.  Then you'd simply pick one of the
FBConfigs associated with the Visual of the root window that has the
attributes you want.  "Applying" that FBConfig to the root probably
needs help from an extension.

|                                            ... This means we need some
| way to change what the root window capabilities after the server has
| started. ...

FBConfigs might provide an interface to do that, but I have no idea
whether there's enough mechanism already available in the
implementations.

Allen