PS backend fails to save polar plot

[rubenvb]

This code:

from matplotlib.pyplot import figure

fig = figure()
fig.add_subplot(212, polar=True)

fig.savefig('fail.eps')

fails with this error:

Traceback (most recent call last):
  File "C:\Users\Ruben\Desktop\test.py", line 13, in <module>
    fig.savefig('fail.eps')
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\figure.py", line 1422, in savefig
    self.canvas.print_figure(*args, **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\backends\backend_qt4agg.py", line 167, in print_figure
    FigureCanvasAgg.print_figure(self, *args, **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\backend_bases.py", line 2220, in print_figure
    **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\backend_bases.py", line 1947, in print_eps
    return ps.print_eps(*args, **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\backends\backend_ps.py", line 981, in print_eps
    return self._print_ps(outfile, 'eps', *args, **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\backends\backend_ps.py", line 1009, in _print_ps
    **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\backends\backend_ps.py", line 1102, in _print_figure
    self.figure.draw(renderer)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\figure.py", line 1035, in draw
    func(*args)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\axes.py", line 2088, in draw
    a.draw(renderer)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\axis.py", line 1101, in draw
    tick.draw(renderer)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\axis.py", line 235, in draw
    self.gridline.draw(renderer)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\lines.py", line 563, in draw
    drawFunc(renderer, gc, tpath, affine.frozen())
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\lines.py", line 939, in _draw_lines
    self._lineFunc(renderer, gc, path, trans)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\lines.py", line 994, in _draw_dotted
    renderer.draw_path(gc, path, trans)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\backends\backend_ps.py", line 575, in draw_path
    self._draw_ps(ps, gc, rgbFace)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\backends\backend_ps.py", line 907, in _draw_ps
    id = self._get_clip_path(clippath, clippath_trans)
  File "C:\WinPython-64bit-3.3.3.2\python-3.3.3.amd64\lib\site-packages\matplotlib\backends\backend_ps.py", line 556, in _get_clip_path
    id = self._clip_paths.get((clippath, clippath_transform))
TypeError: unhashable type: 'Affine2D'

This cannot be intentional.

[tacaswell]

What version of mpl are you using?

[rubenvb]

I'm using Version 1.3.1 as distributed by WinPython and/or http://www.lfd.uci.edu/~gohlke/pythonlibs/.

[fruitfrisje]

Are there already solutions to this problem, I'm having the same problem. It is in the matplotlib that it can't save polar plots....

[tacaswell]

@pelson Smells like something is going wrong in the transform stack.

[tacaswell]

@fruitfrisje @rubenvb I can not reproduce this on something close to current master. Can either of you test this using the master branch?

[fruitfrisje]

Try this:

phi = linspace(0, 2_pi, 200)
figure()
polar(phi, sin(phi)_cos(phi))
grid(True)
savefig("plot_polar.eps", format = 'eps', dpi=1000)

It will give the error.

(using python 3.3.3 with Spyder 2.3.0beta3)

[tacaswell]

@fruitfrisje What version of mpl are you using? (matplotlib.__version__)

[tacaswell]

I can confirm this on master on 3.3, not on 2.7.

This is a side effect of the change in 3 that if a class defines __eq__ then the default __hash__ goes away.

[fruitfrisje]

Sorry for the late reply (out of office), MPL version 1.3.1. We are now gong to test is in python 2.7.3. Will let you know. Is there already a workaround to solve this class problem?

[pelson]

I've not tried it, but as a workaround, before you construct the polar plot, try:

import matplotlib.transforms as mtrans
mtrans.Affine2D.__hash__ = id

This will define a hash function on the affine transform based on the object ID (as it is in Python2) and should fix the problem. @tacaswell also has a fix in the pipeline for v1.4.

HTH

[fruitfrisje]

The following error shows up:

TypeError: id() takes exactly one argument (0 given)

[pelson]

Clearly there is always something to learn with Python as I don't fully undersand what the problem is, but replacing that line with:

mtrans.Affine2D.__hash__ = lambda self: id(self)

Should be fine. Anyone care to give me a lesson in Python?

[fruitfrisje]

@pelson the suggested code above works perfect! Thank you very much so far!!

A totally other question. Is it also possible to save an excel range to an eps? (the range consists of values and text)