MNT: Refactor animation handling of 'bbox_inches'.

dopplershift · dopplershift · commit 949ecdd4857c · 2016-05-15T11:27:03.000-06:00
Instead of a hard-coded look for either instance types or strings, make
it a property of the MovieWriter instances. Set the flag to true by
default for the MovieFileWriters (which all seem to work fine) and make
it false by default for MovieWriters (which are currently pipe-based and
break). We can also eliminate looking at strings by doing the check
after we create the instance of MovieWriter (if necessary).
diff --git a/lib/matplotlib/animation.py b/lib/matplotlib/animation.py
@@ -35,6 +35,7 @@
     from base64 import encodestring as encodebytes
 import contextlib
 import tempfile
+import warnings
 from matplotlib.cbook import iterable, is_string_like
 from matplotlib.compat import subprocess
 from matplotlib import verbose
@@ -109,6 +110,11 @@ class MovieWriter(object):
     frame_format: string
         The format used in writing frame data, defaults to 'rgba'
     '''
+
+    # Specifies whether the size of all frames need to be identical
+    # i.e. whether we can use savefig.bbox = 'tight'
+    frame_size_can_vary = False
+
     def __init__(self, fps=5, codec=None, bitrate=None, extra_args=None,
                  metadata=None):
         '''
@@ -283,6 +289,11 @@ def isAvailable(cls):
 
 class FileMovieWriter(MovieWriter):
     '`MovieWriter` subclass that handles writing to a file.'
+
+    # In general, if frames are writen to files on disk, it's not important
+    # that they all be identically sized
+    frame_size_can_vary = True
+
     def __init__(self, *args, **kwargs):
         MovieWriter.__init__(self, *args, **kwargs)
         self.frame_format = rcParams['animation.frame_format']
@@ -712,29 +723,6 @@ def save(self, filename, writer=None, fps=None, dpi=None, codec=None,
         if savefig_kwargs is None:
             savefig_kwargs = {}
 
-        # FIXME: Using 'bbox_inches' doesn't currently work with
-        # writers that pipe the data to the command because this
-        # requires a fixed frame size (see Ryan May's reply in this
-        # thread: [1]). Thus we drop the 'bbox_inches' argument if it
-        # exists in savefig_kwargs.
-        #
-        # [1] (http://matplotlib.1069221.n5.nabble.com/
-        # Animation-class-let-save-accept-kwargs-which-
-        # are-passed-on-to-savefig-td39627.html)
-        #
-        if 'bbox_inches' in savefig_kwargs:
-            if not (writer in ['ffmpeg_file', 'mencoder_file'] or
-                    isinstance(writer,
-                               (FFMpegFileWriter, MencoderFileWriter))):
-                print("Warning: discarding the 'bbox_inches' argument in "
-                      "'savefig_kwargs' as it is only currently supported "
-                      "with the writers 'ffmpeg_file' and 'mencoder_file' "
-                      "(writer used: "
-                      "'{0}').".format(
-                          writer if isinstance(writer, six.string_types)
-                          else writer.__class__.__name__))
-                savefig_kwargs.pop('bbox_inches')
-
         # Need to disconnect the first draw callback, since we'll be doing
         # draws. Otherwise, we'll end up starting the animation.
         if self._first_draw_id is not None:
@@ -778,7 +766,6 @@ def save(self, filename, writer=None, fps=None, dpi=None, codec=None,
                                          extra_args=extra_args,
                                          metadata=metadata)
             else:
-                import warnings
                 warnings.warn("MovieWriter %s unavailable" % writer)
 
                 try:
@@ -792,6 +779,23 @@ def save(self, filename, writer=None, fps=None, dpi=None, codec=None,
 
         verbose.report('Animation.save using %s' % type(writer),
                        level='helpful')
+
+        # FIXME: Using 'bbox_inches' doesn't currently work with
+        # writers that pipe the data to the command because this
+        # requires a fixed frame size (see Ryan May's reply in this
+        # thread: [1]). Thus we drop the 'bbox_inches' argument if it
+        # exists in savefig_kwargs.
+        #
+        # [1] (http://matplotlib.1069221.n5.nabble.com/
+        # Animation-class-let-save-accept-kwargs-which-
+        # are-passed-on-to-savefig-td39627.html)
+        #
+        if 'bbox_inches' in savefig_kwargs and not writer.frame_size_can_vary:
+            warnings.warn("Warning: discarding the 'bbox_inches' argument in "
+                          "'savefig_kwargs' as it not supported by "
+                          "{0}).".format(writer.__class__.__name__))
+            savefig_kwargs.pop('bbox_inches')
+
         # Create a new sequence of frames for saved data. This is different
         # from new_frame_seq() to give the ability to save 'live' generated
         # frame information to be saved later.
