GtkTextHandle was neglected by whoever removed the ::draw signal,
leaving it entirely broken. Update to using GtkGizmo so we can
implement snapshot of text handles.
Input has received a revamp too, handling is done through a
GtkGestureDrag and coordinate calculations simplified by storing
the delta to the hotspot on ::begin instead of ::update, as this
value is constant throughout the gesture. Widget state management
on crossing events happens implicitly, so no longer needs to be
done here.
Last but not least, CSS has also been updated so handles are
rendered at the correct size and proportion, and with the padding
that code expects of it.
Set up a gesture on the sidebar rows to detect pointer clicks on
it. The row DnD management has been moved to the row widget itself,
it makes more sense even if the drag is began from the sidebar widget.
We still need a drag gesture both on front (capture) and back (bubble)
to handle dragging from both the GtkWindow widget and chrome in the
headerbar. But we can do it through 2 drag gestures, instead of special
event handling code.
This has been broken since we switched key event delivery to follow
the same semantics than pointer/touch. There, GTK+ grabs will influence
the topmost widget during event delivery, rendering the toplevel
unable to handle key navigation. The toplevel must handle those key
events in an explicit manner then.
We don't render the keyboard focus rectangle yet, but I assume that's
something else.
Use an event controller on GtkFontChooserDialog, a nice side effect
is that we can use gtk_event_controller_key_forward() and
gtk_search_entry_set_key_capture_widget() instead of passing events
around for dialog search.
Instead of doing all handling manually in the ::event vfunc,
set up drag/multipress gestures on icon images, and implement
emission of ::icon-press/release and DnD there.
As a side effect, the GdkEvent field in ::icon-press/release
signals has been dropped. Callers that might be interested on it
may still use gtk_get_current_event*().
This isn't really necessary, if keyboard focus forcibly goes somewhere
else we will get ::grab-notify, which is sufficient to deactivate the
button again.
Selected rows in tree views in HighContrast have a background colour the
same or nearly as the normal text colour, so we cannot let entries in
such rows have transparent backgrounds, or the text inside the entry
becomes nearly or totally impossible to see.
Dodge this by giving entry.flat inside treeview and with :focus the
$base_color, which is different from the text & so lets that be seen.
https://gitlab.gnome.org/GNOME/gtk/merge_requests/125
