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Handle floating point round-off error when converting to pixels for h264 animations #8253

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Merged
merged 7 commits into from
Apr 3, 2017
+71 −12
Merged

Handle floating point round-off error when converting to pixels for h264 animations #8253

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d8c6b56
Round the output of adjusted_figsize to avoid floating point roundoff…
Mar 10, 2017
feec74d
Adjust the frame size before writing to disk in case a library outsid…
Mar 10, 2017
30d5b61
use nextafter to correct floating point round-off error
Mar 10, 2017
08eb434
add test for movie writing floating point roundoff issues
Mar 12, 2017
926a59f
don't attempt to use libav ffmpeg shim on ubuntu 12.04
Mar 13, 2017
f287ac6
make test case a little clearer
Mar 15, 2017
5d4f5de
DOC/MNT : add docs + make helper function private
tacaswell Apr 3, 2017
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add test for movie writing floating point roundoff issues
  • Loading branch information
Nathan Goldbaum committed Mar 13, 2017
commit 08eb4347aacc48a856627720bc73350f4379e08a
1 change: 1 addition & 0 deletions .travis.yml
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Expand Up @@ -13,6 +13,7 @@ addons:
packages:
- inkscape
- libav-tools
- libavcodec-extra-53
- gdb
- mencoder
- dvipng
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7 changes: 5 additions & 2 deletions lib/matplotlib/animation.py
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Expand Up @@ -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):
'''
Expand All @@ -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.
Expand Down Expand Up @@ -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,
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11 changes: 10 additions & 1 deletion lib/matplotlib/tests/test_animation.py
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Expand Up @@ -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,
Expand All @@ -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")
Expand Down