This gives greater control to the callers on the place where a grab is being
activated, this may make a difference in the handling of crossing events
triggered through it, e.g. by having callers rely on having already obtained
a ClutterGrab prior to handling the resulting effects.
The "input only" grab has also been turned inactive by default, in order to
to have the ClutterGrab pointer available for checks at the MetaWaylandEventHandler
focus changing methods triggered through grab activation.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/3463
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3747>
The MetaWaylandPointer used to put this together through
MetaCursorTracker cursor visibility, and ClutterSeat-level
inhibition API, applying the pointer focus changes due to
visibility logically to Wayland clients.
In order to make this work over all Clutter widgetry
instead of just Wayland clients, make the ClutterSeat-level
inhibition API control this feature at the ClutterStage picking
level, and leave/enter the seat pointer as appropriate.
By default, the seat pointer has (un)focus inhibited. The
MetaCursorTracker has been made another player in unfocus
inhibition, simply asking for the pointer to get its focus
while the cursor is visible.
This in practice means that picking code may return a NULL
actor, some asserts and preconditions had to be changed to
handle this, plus some test code slightly.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3420>
An input only grab is a ClutterGrab on the stage that doesn't have an
explicit actor associated with it. This is useful for cases where event
should be captured as if focus was stolen to some mysterious place that
doesn't have anything in the scene graph that represents it.
Internally, it's implemented using a 0x0 sized actor attached directly
to the stage, and a clutter action that consumes the events. An
input-only grab takes a handler, user data and a destroy function for
the user data. These are handed to the ClutterAction, which handles the
actual event handling.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2628>
Since we want these accessed from bindings this must be a boxed
type. This has the side effect of making ClutterGrab a refcounted
object, since we want to avoid JS from pointing to freed memory
and maybe causing crashes if misusing the object after dismiss.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2099>
