Non-interactive use always tries to load wx

Community matplotlib-users
1

Hi,
I am trying to use matplotlib non-interactively but if I don't have
DISPLAY set then wx barfs even though I have tried forcing the backend,
etc..

eg..
[midget 16:51] ~/projects/beermon >python
Python 2.5.1 (r251:54863, Aug 14 2007, 11:27:14)
[GCC 3.4.6 [FreeBSD] 20060305] on freebsd6
Type "help", "copyright", "credits" or "license" for more information.

import pylab, matplotlib

matplotlib.use>>> matplotlib.use('agg')

fig = pylab.figure()

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.5/site-packages/matplotlib/pylab.py", line 859, in figure
    figManager = new_figure_manager(num, figsize=figsize, dpi=dpi, facecolor=facecolor, edgecolor=edgecolor, frameon=frameon, FigureClass=FigureClass, **kwargs)
  File "/usr/local/lib/python2.5/site-packages/matplotlib/backends/backend_wxagg.py", line 134, in new_figure_manager
    backend_wx.wxapp = wx.PySimpleApp()
  File "/usr/local/lib/python2.5/site-packages/wx-2.6-gtk2-unicode/wx/_core.py", line 7791, in __init__
    wx.App.__init__(self, redirect, filename, useBestVisual, clearSigInt)
  File "/usr/local/lib/python2.5/site-packages/wx-2.6-gtk2-unicode/wx/_core.py", line 7700, in __init__
    self._BootstrapApp()
  File "/usr/local/lib/python2.5/site-packages/wx-2.6-gtk2-unicode/wx/_core.py", line 7352, in _BootstrapApp
    return _core_.PyApp__BootstrapApp(*args, **kwargs)
SystemError: wxEntryStart failed, unable to initialize wxWidgets! (Is DISPLAY set properly?)

Same problem if I try Cairo.
I had a google but no luck, can anyone help me out?

Thanks.

···

--
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C

2

Daniel O'Connor wrote:

Hi,
I am trying to use matplotlib non-interactively but if I don't have
DISPLAY set then wx barfs even though I have tried forcing the backend,
etc..

This is characteristic of matplotlib that I think should be considered a major bug, but I have not gotten around to fixing it: you have to call matplotlib.use() *before* importing pylab for it to have any effect. If you call it after the first import of pylab, it is silently ineffective, hence highly misleading. Many people are caught by this "gotcha".

I will fix this shortly by making matplotlib.use() raise an exception if matplotlib.backends has already been loaded.

Eric

···

eg..
[midget 16:51] ~/projects/beermon >python
Python 2.5.1 (r251:54863, Aug 14 2007, 11:27:14)
[GCC 3.4.6 [FreeBSD] 20060305] on freebsd6
Type "help", "copyright", "credits" or "license" for more information.

import pylab, matplotlib

matplotlib.use>>> matplotlib.use('agg')

fig = pylab.figure()

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.5/site-packages/matplotlib/pylab.py", line 859, in figure
    figManager = new_figure_manager(num, figsize=figsize, dpi=dpi, facecolor=facecolor, edgecolor=edgecolor, frameon=frameon, FigureClass=FigureClass, **kwargs)
  File "/usr/local/lib/python2.5/site-packages/matplotlib/backends/backend_wxagg.py", line 134, in new_figure_manager
    backend_wx.wxapp = wx.PySimpleApp()
  File "/usr/local/lib/python2.5/site-packages/wx-2.6-gtk2-unicode/wx/_core.py", line 7791, in __init__
    wx.App.__init__(self, redirect, filename, useBestVisual, clearSigInt)
  File "/usr/local/lib/python2.5/site-packages/wx-2.6-gtk2-unicode/wx/_core.py", line 7700, in __init__
    self._BootstrapApp()
  File "/usr/local/lib/python2.5/site-packages/wx-2.6-gtk2-unicode/wx/_core.py", line 7352, in _BootstrapApp
    return _core_.PyApp__BootstrapApp(*args, **kwargs)
SystemError: wxEntryStart failed, unable to initialize wxWidgets! (Is DISPLAY set properly?)

Same problem if I try Cairo.
I had a google but no luck, can anyone help me out?

Thanks.

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