Instead of the 'pre-paint' signal on MetaCompositor, rely directly on
the 'before-update' signal on the stage. A reason for this is that the
callback should not only invoked in connection to painting, but updating
in general. Currently the 'pre-paint' signal is emitted no matter
whether there were any painting or not, but that's both misleading and
will go away.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1285
The MetaLater functionality needs to make sure an update is scheduled so
that it can run its callbacks etc. This used a ClutterTimeline (which is
an object more or less meant to drive animations markers, frames etc)
just to keep the master frame clock running. We're moving away from a
single master clock, so just schedule updates directly instead, with the
newly exposed API.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1285
We need to coordinate with MetaCompositor during pre-paint so that we
have control over whether MetaLater callbacks happen first, or the
MetaCompositor pre-paint logic.
In order to do so, make MetaLater listen to a new signal "pre-paint" on
MetaCompositor, that is called MetaCompositors own pre-paint handling.
This fixes an issue where the top window actor was calculated after the
MetaCompositor pre-paint handling, meaning the top actor being painted
was out-of-date.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
Since the order of destruction during MetaDisplay tear down is a bit
unordered, there are pieces that try to destruct its compositing
dependent pieces (i.e. queued MetaLater callbacks) after MetaCompositor
has been cleaned up, meaning we need to put some slightly awkward NULL
checks to avoid crashing.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
While at it, fix some style inconsistencies, for now use a single
singleton struct instead of multiple static variables, and
other non-functional cleanups. Semantically, there is no changes
introduced.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
