Re-did the painting logic, and document it.
It is unclear to me what is the previous painting logic. But the current
one is basically this:
1. Go through all windows top to bottom, and put visible windows (not
unmapped, opacity > 0, etc) into a linked list, from bottom to top
2. Accumulate a region of ignore on each window, which is basically the
region of screen that is obscured by all the windows above current
one.
3. Paint all the visible windows from bottom to top. Subtract the region
of ignore from the painting region. If we need to paint shadow, we
subtract the body of the window from the shadow painting region too,
because we don't want shadow behind the window.
4. region of ignore is invalidated when window stack change, an
window on top moved or changed shape, when window changed between
opaque and transparent, etc.
Notes:
It is unclear whether all the different shapes of a window (extents,
noframe, border, bounding shape, etc) are calculated correctly or not.
It is unclear if window shape related events are handled correctly or
not. Need more testing.
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
Instead use win_has_alpha to check for alpha channel, window mode is
reserved for determine if the window is possibly transparent.
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
No functional changes intended. The new xcb_damage_query_version() was
previously done by XDamageQueryExtension() internally.
Signed-off-by: Uli Schlachter <psychon@znc.in>
There seems to be a race between DamageAdd (what the client uses
to report damage to Xserver) and DamageSubtract (what compton uses
to clear the reported damage, so it can receive new ones). I am not
sure how to confirm this. But this (terrible) workaround seems to
solve this problem.
* Move code around
* Remove unneeded forward declaration
* Rename win->damaged to win->ever_damaged, to be less confusing
* Expose debug functions even when DEBUG is not enabled. Compiler
would remove the dead code for us anyway.
* Some code cleanup
Also move static function prototypes out of compton.h. Seems like the
previous developers didn't know what header files are for.
Seems to have bugs after the split.
