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Tracer avec Matplotlib dans Python 3 pylab: erreurs Tkinter et Qt FontManager

J'essaie d'utiliser pylab (c'est-à-dire $ ipython3 --pylab) dans Python 3 sur Ubuntu 14.04. Je rencontre la même erreur, que j'utilise les moteurs Tkinter ou Qt4.

AttributeError: 'FontManager' object has no attribute 'ttf_lookup_cache'

Cette même routine de tracé de base (plt.plot([1,2,3,4])) fonctionne cependant dans le pylab Python 2.

A ma connaissance, j'ai installé les dépendances nécessaires (remarque, pour Python 2 et Python 3):

Sudo apt-get install python-numpy python-scipy python-matplotlib
Sudo apt-get install python3-numpy python3-scipy python3-matplotlib
Sudo apt-get install python-tk python3-tk
Sudo apt-get install libqt4gui libqt4core python-qt4 python3-qt4

Les retraits complets sont disponibles ci-dessous. Voici avec Tkinter:

$ ipython3 --matplotlib tk
Python 3.4.0 (default, Apr 11 2014, 13:05:11) 
Type "copyright", "credits" or "license" for more information.

IPython 1.2.1 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: import matplotlib.pyplot as plt

In [2]: plt.plot([1,2,3,4])
Out[2]: [<matplotlib.lines.Line2D at 0x7f1496dc9c50>]

In [3]: Exception in Tkinter callback
Traceback (most recent call last):
  File "/usr/lib/python3.4/tkinter/__init__.py", line 1490, in __call__
    return self.func(*args)
  File "/usr/lib/python3.4/tkinter/__init__.py", line 535, in callit
    func(*args)
  File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_tkagg.py", line 363, in idle_draw
    self.draw()
  File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_tkagg.py", line 348, in draw
    FigureCanvasAgg.draw(self)
  File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_agg.py", line 451, in draw
    self.figure.draw(self.renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/matplotlib/figure.py", line 1035, in draw
    func(*args)
  File "/usr/lib/python3/dist-packages/matplotlib/artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/matplotlib/axes.py", line 2088, in draw
    a.draw(renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/matplotlib/axis.py", line 1094, in draw
    renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/axis.py", line 1043, in _get_tick_bboxes
    extent = tick.label1.get_window_extent(renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/text.py", line 755, in get_window_extent
    bbox, info, descent = self._get_layout(self._renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/text.py", line 321, in _get_layout
    ismath=False)
  File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_agg.py", line 214, in get_text_width_height_descent
    font = self._get_agg_font(prop)
  File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_agg.py", line 258, in _get_agg_font
    fname = findfont(prop)
  File "/usr/lib/python3/dist-packages/matplotlib/font_manager.py", line 1362, in findfont
    font = fontManager.findfont(prop, **kw)
  File "/usr/lib/python3/dist-packages/matplotlib/font_manager.py", line 1202, in findfont
    font_cache = self.ttf_lookup_cache
AttributeError: 'FontManager' object has no attribute 'ttf_lookup_cache'

Et voici avec Qt/Qt4:

$ ipython3 --matplotlib qt
WARNING: Attempting to work in a virtualenv. If you encounter problems, please install IPython inside the virtualenv.
Python 3.4.0 (default, Apr 11 2014, 13:05:11) 
Type "copyright", "credits" or "license" for more information.

IPython 1.2.1 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: import matplotlib.pyplot as plt

In [2]: plt.plot([1,2,3,4])
Out[2]: [<matplotlib.lines.Line2D at 0x7f0f840947f0>]

In [3]: Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_qt4.py", line 374, in idle_draw
    self.draw()
  File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_qt4agg.py", line 154, in draw
    FigureCanvasAgg.draw(self)
  File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_agg.py", line 451, in draw
    self.figure.draw(self.renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/matplotlib/figure.py", line 1035, in draw
    func(*args)
  File "/usr/lib/python3/dist-packages/matplotlib/artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/matplotlib/axes.py", line 2088, in draw
    a.draw(renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/artist.py", line 56, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/matplotlib/axis.py", line 1094, in draw
    renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/axis.py", line 1043, in _get_tick_bboxes
    extent = tick.label1.get_window_extent(renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/text.py", line 755, in get_window_extent
    bbox, info, descent = self._get_layout(self._renderer)
  File "/usr/lib/python3/dist-packages/matplotlib/text.py", line 321, in _get_layout
    ismath=False)
  File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_agg.py", line 214, in get_text_width_height_descent
    font = self._get_agg_font(prop)
  File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_agg.py", line 258, in _get_agg_font
    fname = findfont(prop)
  File "/usr/lib/python3/dist-packages/matplotlib/font_manager.py", line 1362, in findfont
    font = fontManager.findfont(prop, **kw)
  File "/usr/lib/python3/dist-packages/matplotlib/font_manager.py", line 1202, in findfont
    font_cache = self.ttf_lookup_cache
AttributeError: 'FontManager' object has no attribute 'ttf_lookup_cache'

If you suspect this is an IPython bug, please report it at:
    https://github.com/ipython/ipython/issues
or send an email to the mailing list at [email protected]

You can print a more detailed traceback right now with "%tb", or use "%debug"
to interactively debug it.

Extra-detailed tracebacks for bug-reporting purposes can be enabled via:
    %config Application.verbose_crash=True

Dans les deux cas, la fenêtre de tracé apparaît. Dans le cas de Tkinter, le tracé est vide (vide), mais avec Qt4, je vois le résultat correct. L'erreur se déclenche toujours. Encore une fois, cela fonctionne bien avec l'un des deux back-end dans Python 2.7. Qu'est-ce qui me manque?

pythonqtpython3matplotlibtkinter
4
Arthur

J'ai pu résoudre ce problème en supprimant mon cache de polices matplotlib (les caches de polices Python 3 et Python 2), par exemple,

rm /home/arthur/.cache/matplotlib/fontList*.cache

Je peux maintenant utiliser toutes les autres initialisations d'environnement suivantes sans erreurs:

ipython3 --pylab
ipython3 --matplotlib tk
ipython3 --matplotlib qt4
6
Arthur