[cairo] Cool stuff

[Behdad Esfahbod]

On 09/01/2009 08:23 AM, Chris Wilson wrote:
>> To the implementation.  I personally prefer to see the tee not change the
>> >  semantics of master at all.  With that, I see two issues:
>> >
>> >      - create_similar() creates a tee dup'ing all the surfaces.  It should
>> >  simply create_similar(master) IMO.  I simply don't see any use in a tee similar,
>> >
>> >      - acquire_source_image() and snapshot() may return one of the slaves
>> >  depending on type.  I understand why this is being done.  However, it may fail
>> >  very badly since the slaves and master may have had different initial content.
>> >     They are not exchangeable.
> The reason why I had to do this was to ensure that a meta-surface could
> capture a full DAG of the operations that affected the surface (i.e. I
> need to the meta-surface to capture meta-surface snapshots and not just
> images from the master surface). This is a vital necessity for the
> debugging tools that try to retrospectively determine the failing
> operation.

I see.  I suggest making a separate logging surface for that purpose though.

behdad