[Xr] Xr surface management

[Carl Worth]

On Apr 22, Owen Taylor wrote:
 > > There's also
 > > a mechanism (XrSurfaceCreateNextTo) to create a surface of the same
 > > kind as an existing surface. Maybe that one could use a better name.
 > 
 > XrSurfaceClone() ? (It's not necessarily identical, but has the
 > same genes)

XrSurfaceClone might work. Though that name does suggest that the
contents of the surface would also be copied, (not the case for
XrSurfaceCreateNextTo).

Amaury Jacquot proposes XrSurfaceCreateSimilarTo which might be the
right match for the current semantics.

 > I believe the answer to this is "never". So, the operations
 > we want to make easy are:
 > 
 >  - Create a surface for an existing destination with a 
 >    specified visual/colormap.
 > 
 >  - Create a surface with unspecified location and
 >    specified format that can be rendered on efficiently.

Owen, thanks for the feedback here on the surface API. The question
above frames my thinking a bit more clearly. I'll come to some
conclusions later.

 >  - My gut feeling is that you should create an XrColor structure
 >    and use it.

Yes, I think you're right. Xr already has an internal XrColor
structure which I can expose.

-Carl

-- 
Carl Worth                                        
USC Information Sciences Institute                      cworth at isi.edu