Reuse the noninteractivity warning from Figure.show in _Backend.show.

anntzer · anntzer · commit e85e53cef5ba · 2018-05-24T22:38:05.000-07:00
Currently, the warning message "Matplotlib is currently using ..., which
is a non-GUI backend, so cannot show the figure" and the (minor)
associated logic (of catching NonGuiException) is duplicated between
Figure.show and _Backend.show.  Make the latter use the former, to
deduplicate it.
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -185,14 +185,8 @@ def show(cls, block=None):
         if not managers:
             return
         for manager in managers:
-            try:
-                manager.show()
-            except NonGuiException:
-                warnings.warn(
-                    ('matplotlib is currently using %s, which is a ' +
-                     'non-GUI backend, so cannot show the figure.')
-                    % get_backend())
-                return
+            # Emits a warning if the backend is non-interactive.
+            manager.canvas.figure.show()
         if cls.mainloop is None:
             return
         if block is None:
diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -439,10 +439,9 @@ def show(self, warn=True):
             except NonGuiException:
                 pass
         if warn:
-            warnings.warn(
-                ('matplotlib is currently using %s, which is a ' +
-                 'non-GUI backend, so cannot show the figure.')
-                % get_backend())
+            warnings.warn('Matplotlib is currently using %s, which is a '
+                          'non-GUI backend, so cannot show the figure.'
+                          % get_backend())
 
     def _get_axes(self):
         return self._axstack.as_list()
