If window gets exposed but clipboxes doesn't change drivers would avoid
color key fill. This makes XResizeWindo&co to lose colorkey if
background is painted.
To help drivers to avoid filling colorkey for each put server can
provide helper function if there is exposed areas. Server can subtract
exposed areas from filled region.
As a side effect we can avoid useless color key fills if window only
moves in screen without background fills.
v3:
* Change tracking to filled area to account for client initiated clip
changes
* Make overlaid XvPutImage behavior like textured XvPutImage or PutImage
* Make region dynamically allocated only when required.
v4:
* Simplify new driver interface to reduce duplicate code
Signed-off-by: Pauli Nieminen <ext-pauli.nieminen@nokia.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@nokia.com>
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