Remove custom backend_nbagg.show(), putting logic in manager show.

The _Backend class machinery can autogenerate a backend_module.show()
function, which (in short) calls manager.show() on all managers and then
calls the optionally-provided mainloop() function.

backend_nbagg currently completely bypasses this autogeneration because
it wants to additionally fiddle with callbacks and Gcf (it doesn't need
any mainloop()), but that logic can just as well go to
FigureManagerNbAgg.show() instead.  This way it benefits from the
default-generated show; moreover, it seems a bit strange that figures
shown with manager.show() (instead of plt.show()) do indeed get
displayed, but just don't have their callbacks/Gcf-ness adjusted.

This is also related to the move towards putting show()-generating
information on the canvas class for inheritability.

Author: anntzer

lib/matplotlib/backends/backend_nbagg.py

@@ -96,6 +96,15 @@ def show(self):
         else:
             self.canvas.draw_idle()
         self._shown = True
+        # plt.figure adds an event which makes the figure in focus the active
+        # one. Disable this behaviour, as it results in figures being put as
+        # the active figure after they have been shown, even in non-interactive
+        # mode.
+        if hasattr(self, '_cidgcf'):
+            self.canvas.mpl_disconnect(self._cidgcf)
+        if not is_interactive():
+            from matplotlib._pylab_helpers import Gcf
+            Gcf.figs.pop(self.num, None)
 
     def reshow(self):
         """
@@ -232,27 +241,3 @@ def on_message(self, message):
 class _BackendNbAgg(_Backend):
     FigureCanvas = FigureCanvasNbAgg
     FigureManager = FigureManagerNbAgg
-
-    @staticmethod
-    def show(block=None):
-        ## TODO: something to do when keyword block==False ?
-        from matplotlib._pylab_helpers import Gcf
-
-        managers = Gcf.get_all_fig_managers()
-        if not managers:
-            return
-
-        interactive = is_interactive()
-
-        for manager in managers:
-            manager.show()
-
-            # plt.figure adds an event which makes the figure in focus the
-            # active one. Disable this behaviour, as it results in
-            # figures being put as the active figure after they have been
-            # shown, even in non-interactive mode.
-            if hasattr(manager, '_cidgcf'):
-                manager.canvas.mpl_disconnect(manager._cidgcf)
-
-            if not interactive:
-                Gcf.figs.pop(manager.num, None)