Remove all the old 2.x and 3.x version annotations.
GTK+ 4 is a new start, and from the perspective of a
GTK+ 4 developer all these APIs have been around since
the beginning.
GDK has a lock to mark critical sections inside the backends.
Additionally, code that would re-enter into the GTK main loop was
supposed to hold the lock.
Back in the Good Old Days™ this was guaranteed to kind of work only on
the X11 backend, and would cause a neat explosion on any other GDK
backend.
During GTK+ 3.x we deprecated the API to enter and leave the critical
sections, and now we can remove all the internal uses of the lock, since
external API that uses GTK+ 4.x won't be able to hold the GDK lock.
https://bugzilla.gnome.org/show_bug.cgi?id=793124
These functions are entirely trivial, their documentation
is much longer than their implementation, and it contains
an example that is annotated as "don't do this"...
event_widget is not modified anymore after the assignment from
handle_pointing event and we need the event's user data set for the
_gtk_window_check_handle_wm_event call.
It won't stand true anymore that the GdkEventType argument is the
first field of the GdkEvent* structs. All callers have been updated
to use event->any.type instead.
For a start, this makes gtk_main() work different from g_main_loop_run()
calls.
But most importantly, modern GDK does proper syncing itself and doesn't
need to rely on a catch-all to get it right.
This patch makes that work using 1 of 2 options:
1. Add all missing enums to the switch statement
or
2. Cast the switch argument to a uint to avoid having to do that (mostly
for GdkEventType).
I even found a bug while doing that: clearing a GtkImage with a surface
did not notify thae surface property.
The reason for enabling this flag even though it is tedious at times is
that it is very useful when adding values to an enum, because it makes
GTK immediately warn about all the switch statements where this enum is
relevant.
And I expect changes to enums to be frequent during the GTK4 development
cycle.
Those should be interpreted by widget-local gestures, not guessed at a
high level with no notions of the specific context. Users will want
GtkGestureMultiPress to replace these events.
This change is made for consistency, it doesn't make sense to expose
one-way propagation, as it can only break expectations from GTK+. This
function might be made entirely private in the future, but it still
makes sense to do this in one go for our internal usecases.
As we now refrain from sending the crossing events if there's an
implicit grab, those events must be sent on button release when
the implicit grab is broken.
Check the grab widget (both explicit and implicit) and check for a cursor
from the target widget up to this grab widget. If the target widget is
outside the grab widget, only the grab wigdet's cursor will be checked.
This also means that we have to ensure the cursor is updated on button
releases, as an implicit grab being deactivated must trigger a cursor
lookup from the target widget.
