Mutters event filter can prevent events from getting processed by
Clutter, this can also happen for TOUCH_END/CANCEL events. Processing
these events in Clutter is crucial for proper tracking of touch
sequences though, that's because Clutter adds a PointerDeviceEntry to
the stage on a TOUCH_BEGIN *before* going through the event filter, but
removes that entry on a TOUCH_END *after* going through the filter. So
Clutter really needs to see those TOUCH_END events, or else there will
be a stale PointerDeviceEntry on the ClutterStage.
Make sure those TOUCH_END/CANCEL events always get seen by Clutter by
removing the device entry immediately when those get filtered out.
Because there might still be events belonging to this sequence in the
event queue of the stage, we need to flush the queue before removing the
entry, too.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2350>
Unfortunately we cannot do this generically since the target of the
button/touch press does matter, e.g. tapping on the OSK, or clicking
the IBus candidates window. These situations should not trigger a
reset.
So be more selective about the situations where button/touch presses
trigger an IM reset, in the case of ClutterText these are still clicks
inside the actor, for Wayland's text-input it is when clicking the
surface that has text_input focus.
For all other situations where clicking anywhere else might make
sense to trigger an IM reset are covered by the focus changing paths,
that also ensure a reset before changing focus between surfaces/actors.
Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1961
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2384>
Focus changes should trigger an IM reset, as some engines do want
to maybe commit the preedit buffer before changing focus. Since
the preedit string is also cleared on reset(), we can do without
that explicit call.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2384>
Right now we have a bit of a mixed bag between an active model where
input foci set the surrounding text without being asked for (e.g.
wayland's text_input), and a passive model where the IM engines ask
for content.
Make ClutterText take the same side than text_input, so that dealing
with those is at least consistent.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2384>
The clutter_text_delete_text() function used underneath expects character
offsets for both start/end position. Fix the end position passed an offset
instead of that, and compesnate for the cursor position being always -1
when the caret is at the end of the string.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2384>
I've overseen quite an important case in commit
98a5cb37d9: Repicking only when actors get
destroyed is not enough, we actually need to repick when actors go
hidden/unmapped.
While we could also listen to notify::mapped just like we listen to
notify::reactive, it seems better to avoid using property notifications
here due to the usage of g_object_freeze/thaw_notify() in ClutterActor.
It can lead to the stage receiving a notify::mapped with mapped = true
for a pointer actor, which really shouldn't happen (just like
notify::reactive with reactive = true shouldn't happen).
Fixes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/5124
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2333>
We want all pointer events to be passed through the pointer a11y
processing before going through event filters: Once we go through event
filters, events might be dispatched to Wayland and get filtered out.
With the changes to immediately dispatch events to wayland, this changed
and the pointer a11y is now no longer seeing any events going to wayland
clients. Fix it by shuffling things around a bit and letting pointer
a11y take a peek at events earlier.
Fixes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/5192
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2332>
There's a bunch of crashes right now where the assertions in
clutter_actor_set_mapped() after calling the map/unmap() vfuncs are
failing. The only way this can happen is by re-entering
clutter_actor_set_mapped() during the map/unmap recursion.
The reason for those crashes is that the shell hides/shows some actors
in response to crossing events and key-focus changes. These in turn get
triggered by the newly introduced ungrabbing of ClutterGrabs when an
actor gets unmapped, which triggers GRAB_NOTIFY crossing events and
key-focus changes.
Since these situations are hardly avoidable (it's a valid use-case to
hide/show something in response to a crossing/key-focus event), catch
the set_mapped() call early while we reenter the mapping machinery and
log a warning instead of crashing.
Fixes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/3165
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2299>
With the introduction of untrottled event delivery to wayland clients,
we moved the _clutter_event_process_filters() call outside of
_clutter_process_event(). This also moved the processing of event
filters outside of the timespan where the event is added to Clutters
current_event stack, making Clutter.get_current_event() no longer
available to anything happening inside mutters event filter.
One thing that happens in mutters event filter is detecting and
triggering keybindings like the alt-tab switcher. Now the alt-tab
switcher has a special case where it finishes and activates a window
right when the keybinding gets activated, relying on the current event
time as the timestamp to activate the window.
Now since the current event time is no longer available from inside
mutters event filter, we'd pass 0 to meta_window_activate(), causing
mutter to send a notification instead of actually activating the window.
To fix this, also set a current_event for the ClutterContext when going
through event filters, this makes sure Clutter.get_current_event_time()
works when called inside keybinding handlers.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2327>
In the right combination of circumstances, and given 2 actors (parent
actor P with an offscreen effect and child actor C), we may have the
following situation happening:
- A redraw is queued on the actor C, actors C and P are marked as
priv->is_dirty and priv->propagated_one_redraw.
- During paint() handling we paint actor P, priv->propagated_one_redraw
is turned off.
- We recurse into child actor C, priv->propagated_one_redraw is turned
off.
- A new redraw is queued on actor C, actors C and P are marked as
priv->is_dirty and priv->propagated_one_redraw.
- The paint() method recurses back, actors C and P get priv->is_dirty
disabled, priv->propagated_one_redraw remains set.
- At this point queueing up more redraws on actor C will not propagate
up, because actor C has priv->propagated_one_redraw set, but the
parent actor P has priv->is_dirty unset, so the offscreen effect will
not get CLUTTER_EFFECT_PAINT_ACTOR_DIRTY and will avoid repainting
actor C.
The end result is that actor C does not redraw again, despite requesting
redraws. This situation eventually resolves itself through e.g. relayouts
on actor P, but may take some time to happen.
In order to fix this, consider actors that did get a further redraw
request still dirty after paint().
Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/2188
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2353>
Simplify the function arguments (the origin is just the actor that
the function is originally called from), and make it also handle
marking as dirty the actor that got the redraw queued up explicitly.
This makes it a single place where priv->is_dirty is being enabled.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2353>
We not just have X11 devices, but also virtual devices on both backends.
In the mean time, keep these working on top of a ClutterInputDeviceType,
but transform that into capabilities on device construction so users can
rely on the new flagset.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2331>
This fixes instances of:
```
*** BUG ***
In pixman_region32_init_rect: Invalid rectangle passed
Set a breakpoint on '_pixman_log_error' to debug
```
seen when navigating the overview and launching apps.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2349>
The ClutterGestureAction base code would correctly try to cancel a
gesture if it would receive GRAB_NOTIFY leave events (that would indicate
other portions of the actor tree stole input away from the gesture actor),
but it would mistakenly do so only if the gesture was already initiated,
possibly leaving stale point information if the gesture collected input
but didn't initiate yet.
This could be indirectly seen clicking with the mouse on OSK keys with
no motions in between, clicks would accumulate on the swipeTracker
gestures until the trigger point, so the third click could drag the
workspaces.
We do always want to unregister the related device/sequence here, do that
while still cancelling any already initiated gesture.
Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1907
Fixes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/4987
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2334>
We'll need the additional context of which actor the event will be
emitted to in mutters event filter (see next commit), so pass that
target actor to the event filters that are installed.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2321>
It does not make sense that the event "source" (aka the target) is
both content and recipient of a message. Not doing so, events become
largely independent of the actor that is receiving/handling an
event. This is small step toward making events opaque and immutable.
Every user of these API calls in our code have ported away from
them, but other users may remain in extensions, so make these
functions work on top of the alternative API without accessing the
soon to be removed event field.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2311>
This is just "necessary" for --nested stages, since the pointer is
allowed to leave the stage in that case. Since the only side effect
is that there is still a pointer focus somewhere inside the stage,
simply drop this.
This is a small leftover of commit b8f92a6ce4, since we stopped
handling the double ENTER event there.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2311>
In addition to the presented callback time, it shows the time to the
reported presentation time (which can be earlier or later than the
presented callback), as well as the GPU rendering duration.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1928>
The distribute_natural_allocation() function was copied over from Gtk to
Clutter 11 years ago with commit e636a0bbce.
Gtk only supports integers sizes in its layout machinery, while Clutter
does everything using floats.
Since this function sets the minimum_size (the size we allocate the
children in the end) to an integer, this means we're implicitly
typecasting floats to integers here, effectively floor()'ing all sizes
that we allocate the box children.
A bug this caused in gnome-shell was that a scrollView (like the one in
the endSessionDialog) was showing scrollbars even though the content
perfectly fit inside the view: Say the content and its scrollView parent
request a size of 63.9 px, but get allocated a size of 63 px by a box
layout. Now the scrollView notices that its allocated size is smaller
than the requested size and thus shows a scrollbar.
So fix that and use floats in distribute_natural_allocation() instead of
integers, as we do everywhere else in the layout machinery.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2284>
Without input device grabs in play, all functions that emit
pointer/key/crossing/touch events are pretty much the same. Remove this
duplication and use a common emit_event() function.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2100>
In case of misuse (e.g. passing NULL stage) this might result in crashes
before the precondition checks managed to kick in. Move this priv variable
initialization after these checks.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2099>
Wayland event processing and WM operations are themselves outside the
ClutterGrab loop so far. Until this is sorted out, these pieces of
event handling have got to learn to stay aside while there is a
ClutterGrab going on.
So, synchronize foci and other state when grabs come in or out, and
make it sure that Wayland event processing does not happen while
grabs happen.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2099>
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>
Toggling the click action on when leaving the actor/action sounds weird,
this was presumably meant to toggle it off on leave, and back to in_held
on enter. This way, the CLUTTER_LEAVE handling also matches what we want
to do in case of grabs.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2099>
The lack of handling of regular crossing events here is dubious, perhaps
to be fixed later on. So far, ensure gestures are cancelled whenever
a grab-inducted crossing event would leave this action in the blue.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2099>
This is (luckily!) unused, and it's inconvenient to have a toggle to
break the input model we are striving towards. Drop this function
and stick to the default behavior.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2099>
This looks like a relic of glReadPixels-based picking, the pointer
might well be outside redrawn areas, yet still require a device
update (e.g. in order to reflect the actor layout changes in the
"clear area" info).
Instead, always update all devices that are inside the view after
relayouts, the tracking on the need for that update is now done
on each ClutterStageView, instead of globally in the ClutterStage.
This theoretically fixes situations where pointers might miss
updating their "clear area" after the actor tree changed.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/2117
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2257>
The stage window is an interface, that added properties, that were only
then actually managed by MetaStageImpl. Shuffle things slightly, and let
the MetaStageImpl object deal with these things itself.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2014>
As ClutterGrab is a stack, the backend only cares about some grab
existing currently or not. Make it sure that we grab whenever we
go to >=1 grabs, and ungrab whenever we go to <1.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2068>
Dissociate clutter_stage_set_key_focus() from the actors focused
state, so that it obeys stage grabs. The key focus actor state may
also change due to grab changes, add the code to notify about this.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2068>
Emit crossing events whenever a grab coming or going would cause a
pointer/touchpoint to become inactive on their position. Depending
on whether the pointer lies inside the old or new grab widgets,
enter or leave events would be generated.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2068>
We will want to be more specific about the portions of the actor
hierarchy that receive this event, separate creation and emission
so each place does what is relevant.
However, this commit brings no functional changes.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2068>
These events are not meant to be ever silenced away, every actor
that is meant to receive one should do so. Make it sure that those
events cannot be stopped, despite the event signal handlers return
values.
This opens the debate about whether crossing events should be
ClutterEvents, since they are more and more uncommon at being one,
maybe this notification mechanism should be taken away from the
event machinery, but that's something for future refactors.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2068>
Hopefully, the one to make them all converge. This new ClutterGrab
represents a handle on a created grab. These are stacked, so grabs
can be overridden and remain inactive until there is a time that
they become active again, although undoing these early is optional.
These grabs are global, they do apply to all pointer, touchpoint
and keyboard foci.
At the moment, only the API to create and stack those is added,
the actual functionality is added in future commits.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2068>
A property for reversing the visible order of children is a bit odd.
It has also been unused by actual gnome-shell code since 2010, and the
somewhat related pack_start()/pack_end() API in GtkBox(Layout) is gone
in GTK4.
With that in mind, turn the property into a no-op and deprecate it,
so that it can be dropped next cycle.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2206>
This ensures they remain perfectly smooth regardless of how the
dispatch time has been adjusted/optimized/delayed/jittered.
Idea by Ivan Molodetskikh <yalterz@gmail.com>
For example, dragging a window on a 60Hz monitor:
BEFORE
delta(time_us) = 17014μs
delta(time_us) = 15998μs
delta(time_us) = 17006μs
delta(time_us) = 16975μs
delta(time_us) = 16001μs
delta(time_us) = 17002μs
delta(time_us) = 17006μs
delta(time_us) = 16004μs
AFTER
delta(time_us) = 16667μs
delta(time_us) = 16667μs
delta(time_us) = 16670μs
delta(time_us) = 16667μs
delta(time_us) = 16669μs
delta(time_us) = 16668μs
delta(time_us) = 16664μs
delta(time_us) = 16674μs
Caveat 1: Because we don't know a "next presentation time" on the first
frame, the interval between the first and second frame will usually be
different to the subsequent steady interval. So this change increases the
jitter of just frame 2, but eliminates jitter thereafter.
Caveat 2: `clutter_frame_clock_schedule_update_now` schedules updates
earlier than `clutter_frame_clock_schedule_update`. This means potentially
you could get multiple frames targeting the same "next presentation time".
That doesn't really change here though - we're dispatching at the same
times as we used to and just giving timelines a better vsync-aligned
timestamp now.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/25
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2161>
This won't change anything for 60Hz displays but higher refresh rate
users will benefit.
Using Nvidia EGLStreams on a 240Hz monitor for example (refresh interval
~4.1ms), the maximum render time allowed before dropping to 120Hz is now
3.6ms whereas it was previously 2.1ms.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2158>
This is notably necessary with transformations, since these don't
trigger allocation machinery, but may affect the actor under the
pointer.
Visible e.g. with GNOME Shell's "Application does not respond"
dialogs.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
With Wayland handling all events as they come, this code now just
performs motion compression for events that will be handled by Clutter
widgetry.
The intent to opt tablets and styli out of motion compression was
early and fast client handling, since that is now covered in a generic
manner, this code is superfluous. We don't really need the extra events
for these devices in compositor widgetry either.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
We essentially create those at the time they need to be handled, and
use shortcuts that avoid the event from being queued up. It's too much
of a short cut though, these events are also of interest to the Wayland
event handlers, e.g. to handle pointer state changes (e.g. repicks due
to the pick actor being destroyed) immediately, instead of at the next
event.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
If we are still under the "clear area" of the pick actor, we forget
to update the coordinates. This is usually not needed, unless we
need to repick again for non-event circumstances (e.g. pick actor
is destroyed). This will ensure the right pointer coordinates are
used afterwards in those situations.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
Traditionally, the next repaint would also involve picking, which
would correct the actor under the pointer. This now does not happen
out of the box, so we really are waiting for the next pointer event
here.
To avoid the pointer/cursor to lag behind, trigger an immediate
repick here, that will look up the new actor under the pointer
coordinates.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
And resort to it first, unless we are told to ignore the cache
(e.g. after relayouts). This avoids further pick context operations
while the pointer is on the current actor.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
This safe area is the region (in stage coordinates) where the pointer
is ensured to stay within the current actor. This is not used yet, but
will be used for optimizations in pointer picking.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
These may be used for optimizations once we find the pick actor,
so picking can be avoided in areas we know didn't cross into
other actors. Nothing makes use of it yet though, just log these
so far.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
Add a clutter_stage_pick_and_update_device() method that is the only
single entry point for updating a device position as seen by the
stage.
Also, update all callers to use it.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
The clutter_stage_get_actor_at_pos() calls it almost 1:1 underneath
and is public API, we can have all callers use this, and stop using
this function outside of clutter-stage.c.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
As event handling goes:
1) Events get generated and queued by the seat (from another thread in
native, in the same thread in X11)
2) The MetaBackend gets those events and forwards them to Clutter
via clutter_do_event()
3) The events get queued in the ClutterStage
4) At the time of processing a frame, the input events are processed,
5) Motion events are throttled, only the last is effectively handled
6) Events are filtered, wayland and WM handling happens here
7) Events maybe reach to clutter
This commit moves 6 to happen between 2 and 3. The end result is that:
- Throttling only applies to Clutter event handling, The wayland event
forwarding bits will handle the event stream as soon as it comes, as
timely as possible.
- WM event handling is also unthrottled, but that's more of a side
effect.
- This all still happens on the main thread, so there's the possibility
that other busy areas (e.g. relayout) temporarily block this event
forwarding.
- Sending events unthrottled inherently means more CPU, probably
dependent on input devices' frequency. The impact is not measured.
This should bring the best of both worlds with e.g. 1000Hz mice, wayland
clients get unthrottled events, while GNOME Shell UI still behaves like
it used to do.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
If we wait till finalize, dispose will destroy the actor hierarchy
and cause untimely repicks. Ensure to free the pointer/touch info
first, so the hooked signal callbacks are gone when destroying the
actors.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>
In the case a11y is required, the screen reader is very much
interested in getting an uninterrupted flow of key events. It attempts
so by setting a ::captured-event callback on the ClutterStage, but
that falls short with our MetaDisplay event handler, as clutter events
can be stopped before a11y gets a chance to see them.
This kind of selective amnesia wrt key events is not new, in X11 those
go unheard of by the WM as long as a client is focused and no grabs hold,
so it is clients' responsibility to talk with AT bridge.
This commit doesn't yet change that for X11, but we can do this right
away from the compositor on Wayland, and without any chance to be
tampered by clients.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1328>
If one would end up with an actor attached to mapped actor, where the
attached actor doesn't itself have an up to date stage view list while
listening on the stage for updating, when clearing the stage views of
the list, anything that would query the stage views list at this time
would end up accessing freed memory.
This could happen if
1) An actor was added to a newly created container actor attached to
the stage
2) The actor got a timeline attached to it
3) The actor was moved to a container that already was mapped
4) A hotplug happened
After (1) both the container and actor would not have any stage views.
After (2) the timeline would listen on the stage for stage views
updates. After (3) the actor would still listen on the stage for stage
views updates. When (4) happened, the actor would be signalled when the
stage got its stage view cleared, at which point it would traverse up
its actor's tree finding an appropriate stage view to base its animation
on. The problem here would be that it'd query the already mapped
container and its yet-to-be-cleared stage view list, resulting in
use-after free, resulting in for example the following backtrace:
0) g_type_check_instance_cast ()
1) CLUTTER_STAGE_VIEW ()
2) clutter_actor_pick_frame_clock ()
3) clutter_actor_pick_frame_clock ()
4) update_frame_clock ()
5) on_frame_clock_actor_stage_views_changed ()
6) g_closure_invoke ()
7) signal_emit_unlocked_R ()
8) g_signal_emit_valist ()
9) g_signal_emit ()
10) clear_stage_views_cb ()
11) _clutter_actor_traverse_depth ()
12) _clutter_actor_traverse ()
13) clutter_actor_clear_stage_views_recursive ()
14) clutter_stage_clear_stage_views ()
...
Avoid this issue by making sure that we don't emit 'stage-views-changed'
signals while the actor tree is in an invalid state. While we now end up
traversing tree twice, it doesn't change the Big-O notation. It has not
been measured whether this has any noticible performance impact.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1950
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2025>
This does two things to frown upon:
- Modifies ClutterEvent structs, while the effort is to have those
completely opaque, and readonly after creation from the input
thread side.
- Stores state in the ClutterInputDevice struct, event though those
are also considered static after creation, managed by the input
thread, etc.
Stop doing that. This makes all events just forwarded as-is in
the ClutterStage/clutter-main.c code.
Handling of click count sounds like material for a ClutterGestureAction
(or perhaps ClutterClickAction), all of both callers now do it in place
at the moment, while gestures lack a better state tracking and management.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2024>
