FIX: not all init/draw function return artists

tacaswell · tacaswell · commit 33da7a56d42a · 2015-08-26T23:25:57.000-04:00
For blitted animations in is essential to return a list of the animated
artists.  However, is other cases you can get away with out returning
such a list.

In the case of blitting it is important to make sure that the animation
flags on the animated artist are set correctly, t his commit makes sure
that we check that we actually got an iterable before trying to iterate
over it.
diff --git a/lib/matplotlib/animation.py b/lib/matplotlib/animation.py
@@ -1156,8 +1156,9 @@ def _init_draw(self):
             self._draw_frame(next(self.new_frame_seq()))
         else:
             self._drawn_artists = self._init_func()
-            for a in self._drawn_artists:
-                a.set_animated(self._blit)
+            if iterable(self._drawn_artists):
+                for a in self._drawn_artists:
+                    a.set_animated(self._blit)
 
     def _draw_frame(self, framedata):
         # Save the data for potential saving of movies.
@@ -1170,5 +1171,6 @@ def _draw_frame(self, framedata):
         # Call the func with framedata and args. If blitting is desired,
         # func needs to return a sequence of any artists that were modified.
         self._drawn_artists = self._func(framedata, *self._args)
-        for a in self._drawn_artists:
-            a.set_animated(self._blit)
+        if iterable(self._drawn_artists):
+            for a in self._drawn_artists:
+                a.set_animated(self._blit)
