matplotlib-devel Mailing List for matplotlib

On 2013年09月11日 8:49 AM, Filipe Saraiva wrote:
> Em Ter 10 Set 2013 19:21:01 BRT, Christoph Gohlke escreveu:
>> On 9/10/2013 1:54 PM, Eric Firing wrote:
>>> On 2013年09月10日 5:43 AM, Michael Droettboom wrote:
>>>> Do any of those use ctypes? Try creating a minimal ctypes example and
>>>> see if that works.
>>>
>>> Mike,
>>>
>>> I was a bit horrified to see that ctypes import and usage in mpl;
>>> fortunately it is a workaround for a PySide bug, and should only be
>>> temporary, if it should be there at all.
>>>
>>> Eric
>>>
>>
>> Don't be horrified. The Ctypes workaround went trough the mailing list,
>> a PR with discussions including most core developers, testing, several
>> beta/rc/final versions, and real word usage. It fixes a problem that is
>> still present today without it: the Qt4Agg backend is practically
>> unusable with any recent version of PySide on CPython 3.x. Anyway, the
>> Ctypes code could be put in a try/except statement for environments that
>> don't support Ctypes or Python's C API.
>
> If I understood correctly is there a problem with Qt4Agg in matplotlib
> 1.3?
>
> Another KDE developer typed:
>
> import matplotlib
> from matplotlib import pyplot as plt
>
> In my software (Cantor backend for python) and he got the error below:
>
> Traceback (most recent call last):
> File "", line 1, in
> File "/usr/lib/python2.7/site-packages/matplotlib/pyplot.py", line 98,
> in
> _backend_mod, new_figure_manager, draw_if_interactive, _show =
> pylab_setup()
> File
> "/usr/lib/python2.7/site-packages/matplotlib/backends/__init__.py", line
> 25, in pylab_setup
> globals(),locals(),[backend_name])
> File
> "/usr/lib/python2.7/site-packages/matplotlib/backends/backend_qt4agg.py",
> line 13, in
> from backend_qt4 import QtCore, QtGui, FigureManagerQT, FigureCanvasQT,\
> File
> "/usr/lib/python2.7/site-packages/matplotlib/backends/backend_qt4.py",
> line 25, in
> from qt4_compat import QtCore, QtGui, _getSaveFileName, __version__
> File
> "/usr/lib/python2.7/site-packages/matplotlib/backends/qt4_compat.py",
> line 36, in
> import sip
> ImportError: /usr/lib/python2.7/site-packages/sip.so: undefined symbol:
> PyExc_SystemError
Again, this is a failure of a module to find a Python API symbol. In 
this case, it is not a matplotlib module, it is sip, part of pyqt4. It 
seems like some sort of linking problem.
>
> One more info, I removed matplotlib 1.3 and installed matplotlib 1.2
> using pip and it worked properly. I can use matplotlib in this version.
I'm glad you found something that works; but I don't know why it does.
Eric
>
> Thank you;
>
> --
> Filipe Saraiva
> http://filipesaraiva.info/
>
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