Say you have two 800x600 screens left/right of each other. A window
that's 200x200 at +700+0 in protocol coordinate space will appear to be
at -100+0 in the coordinate space of the right hand screen. Put another
way: windows are in the coordinate space of their root window pixmap.
We weren't doing this translation for the COW, so when rendering came in
to it you'd see the top-left chunk of the COW on all screens. Cool
effect and all, but wrong.
v2: Only translate when Xinerama is active [keithp]
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Adam Jackson <ajax@redhat.com>
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