Now that we have gtk_drag_check_threshold_double(), be consistent with
other draggable widgets and make sure we don't take over a drag before a
child does.
Fixes https://gitlab.gnome.org/GNOME/gtk/-/issues/3513
If multiple nested widgets have drag sources on them, both using bubble
phase, we need to reliably pick the inner one. Both of them will try to
start dragging, and we need to make sure there are no situations where the
outer widget starts drag earlier and cancels the inner one.
Currently, this can easily happen via integer rounding: start and current
coordinates passed into gtk_drag_check_threshold() are initially doubles
(other than in GtkNotebook and GtkIconView), and are casted to ints. Then
those rounded values are used to calculate deltas to compare to the drag
threshold, losing quite a lot of precision along the way, and often
resulting in the outer widget getting larger deltas.
To avoid it, just don't round it. Introduce a variant of the function that
operates on doubles: gtk_drag_check_threshold_double() and use it instead
of the original everywhere.
This was needed to work around widgets claiming event sequences on press,
by ignoring them and starting the drag anyway unless they have certain
event controllers on them.
The most visible offender was GtkButton, but since the last commit it
doesn't claim the sequence anymore and we can remove the hack.
Currently GtkButton claims the sequence both on press and on release. Stop
claiming it on press and only do it on release, allowing drags to start
from it.
This will allow to remove a hack from GtkWindowHandle.
Before turning off pangos rounding of glyph positions,
we must check if the cairo we are using is new enough
to have working subpixel positioning (the relevant
cairo commit is 52a7c79fd4ff96bb5fac175f0199819b0f8c18fc).
This adds a "release" destructor for the gtk_surface1 interface which
signals to the server that a surface has been destroyed on the client
side, which the current "destroy" does not do.
Ideally the protocol would have specified a destroy request marked as
destructor to handle this automatically, however this is no longer
possible due to the destroy method being implicitly generated in the
absence of an explicit request in the protocol. Adding a destroy request
marked as destructor now would generate a new destroy method that
unconditionally would send the request to the server, which would break
clients running on servers not supporting that request.
Setting can-focus to FALSE on a widget is supposed
to prevent focus from entering the entire subtree.
So when we grab focus directly to a widget, we need
to check the can-focus flag not just of the widget
itself, but all its ancestors.
Fixes: #3610
