Merge pull request matplotlib#19435 from anntzer/gtkd

Replace gtk3 deprecated APIs that have simple replacements.

Author: timhoffm

lib/matplotlib/backends/backend_gtk3.py

@@ -125,7 +125,6 @@ def __init__(self, figure):
 
         self.set_events(self.__class__.event_mask)
 
-        self.set_double_buffered(True)
         self.set_can_focus(True)
 
         renderer_init = _api.deprecate_method_override(
@@ -181,7 +180,7 @@ def key_release_event(self, widget, event):
 
     def motion_notify_event(self, widget, event):
         if event.is_hint:
-            t, x, y, state = event.window.get_pointer()
+            t, x, y, state = event.window.get_device_position(event.device)
         else:
             x, y = event.x, event.y
 
@@ -339,20 +338,16 @@ def __init__(self, canvas, num):
 
         self.toolbar = self._get_toolbar()
 
-        def add_widget(child):
-            child.show()
-            self.vbox.pack_end(child, False, False, 0)
-            size_request = child.size_request()
-            return size_request.height
-
         if self.toolmanager:
             backend_tools.add_tools_to_manager(self.toolmanager)
             if self.toolbar:
                 backend_tools.add_tools_to_container(self.toolbar)
 
         if self.toolbar is not None:
             self.toolbar.show()
-            h += add_widget(self.toolbar)
+            self.vbox.pack_end(self.toolbar, False, False, 0)
+            min_size, nat_size = self.toolbar.get_preferred_size()
+            h += nat_size.height
 
         self.window.set_default_size(w, h)