add test for movie writing floating point roundoff issues

Nathan Goldbaum · Nathan Goldbaum · commit 08eb4347aacc · 2017-03-13T12:00:45.000-05:00
diff --git a/.travis.yml b/.travis.yml
@@ -13,6 +13,7 @@ addons:
     packages:
       - inkscape
       - libav-tools
+      - libavcodec-extra-53
       - gdb
       - mencoder
       - dvipng
diff --git a/lib/matplotlib/animation.py b/lib/matplotlib/animation.py
@@ -288,8 +288,11 @@ def _adjust_frame_size(self):
                 verbose.report('figure size (inches) has been adjusted '
                                'from %s x %s to %s x %s' % (wo, ho, w, h),
                                level='helpful')
+        else:
+            w, h = self.fig.get_size_inches()
         verbose.report('frame size in pixels is %s x %s' % self.frame_size,
                        level='debug')
+        return w, h
 
     def setup(self, fig, outfile, dpi=None):
         '''
@@ -311,7 +314,7 @@ def setup(self, fig, outfile, dpi=None):
         if dpi is None:
             dpi = self.fig.dpi
         self.dpi = dpi
-        self._adjust_frame_size()
+        self._w, self._h = self._adjust_frame_size()
 
         # Run here so that grab_frame() can write the data to a pipe. This
         # eliminates the need for temp files.
@@ -347,7 +350,7 @@ def grab_frame(self, **savefig_kwargs):
         verbose.report('MovieWriter.grab_frame: Grabbing frame.',
                        level='debug')
         try:
-            self._adjust_frame_size()
+            self.fig.set_size_inches(self._w, self._h)
             # Tell the figure to save its data to the sink, using the
             # frame format and dpi.
             self.fig.savefig(self._frame_sink(), format=self.frame_format,
diff --git a/lib/matplotlib/tests/test_animation.py b/lib/matplotlib/tests/test_animation.py
@@ -145,6 +145,14 @@ def test_save_animation_smoketest(tmpdir, writer, extension):
     ax.set_xlim(0, 10)
     ax.set_ylim(-1, 1)
 
+    dpi = None
+    codec = None
+    if writer == 'ffmpeg':
+        # Issue #8253
+        fig.set_size_inches((10.85, 9.2000000000000011))
+        dpi = 100.
+        codec = 'h264'
+
     def init():
         line.set_data([], [])
         return line,
@@ -160,7 +168,8 @@ def animate(i):
     with tmpdir.as_cwd():
         anim = animation.FuncAnimation(fig, animate, init_func=init, frames=5)
         try:
-            anim.save('movie.' + extension, fps=30, writer=writer, bitrate=500)
+            anim.save('movie.' + extension, fps=30, writer=writer, bitrate=500,
+                      dpi=dpi, codec=codec)
         except UnicodeDecodeError:
             pytest.xfail("There can be errors in the numpy import stack, "
                          "see issues #1891 and #2679")
