In many places Cairo maps/unmaps surfaces to perform operations on the
raw image, but it doesn't care about the format being invalid. All of
these are appropriate users of _cairo_surface_map_to_image().
Only allow one owner to keep their snapshot on the subsurface, and
so automatically replace any previous snapshot.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
If the sample is wholly contained within the subsurface of the original,
we can simply use the original with an offset; thereby only copying the
data if we are sampling outside the subsurface bounds.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Having spent the last dev cycle looking at how we could specialize the
compositors for various backends, we once again look for the
commonalities in order to reduce the duplication. In part this is
motivated by the idea that spans is a good interface for both the
existent GL backend and pixman, and so they deserve a dedicated
compositor. xcb/xlib target an identical rendering system and so they
should be using the same compositor, and it should be possible to run
that same compositor locally against pixman to generate reference tests.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
P.S. This brings massive upheaval (read breakage) I've tried delaying in
order to fix as many things as possible but now this one patch does far,
far, far too much. Apologies in advance for breaking your favourite
backend, but trust me in that the end result will be much better. :)
