No need to process_updates in gtk3.

anntzer · anntzer · commit d96d1048cdf2 · 2018-01-08T22:27:55.000-08:00
gdk_window_process_updates is deprecated since GDK 3.22.  Agg animations
run fine without it, and removing it makes mpl_cairo animations faster.

Being drawable is synonym to being mapped and visible.
diff --git a/lib/matplotlib/backends/backend_gtk3.py b/lib/matplotlib/backends/backend_gtk3.py
@@ -275,11 +275,8 @@ def on_draw_event(self, widget, ctx):
         pass
 
     def draw(self):
-        if self.get_visible() and self.get_mapped():
+        if self.is_drawable():
             self.queue_draw()
-            # do a synchronous draw (its less efficient than an async draw,
-            # but is required if/when animation is used)
-            self.get_property("window").process_updates (False)
 
     def draw_idle(self):
         if self._idle_draw_id != 0:
