[SciPy-user] Solved-ish: matplotlib, Tkinter and multi-threaded web applications

[Robert Kern]

zunzun at zunzun.com wrote:
> On Sun, Oct 14, 2007 at 05:09:36PM -0500, Robert Kern wrote:
>> Umm, only the TkAgg backend uses Tk. Why not just use a backend that doesn't
>> have a GUI? Specify
>>
>> backend : Agg
>>
>> in your .matplotlibrc or call matplotlib.use('Agg') before importing pylab.
> 
> Tried it, didn't work.  Tk is still started and gave a threading
> error.  It might not be used, but it does start in my tests.

Please show us the code that you used on the matplotlib list. This would be a
bug. For example, I have 'WXAgg' set as the backend in my matplotlibrc, but if I
call matplotlib.use('Agg') before loading pylab, wx never gets loaded:


[~]$ ipython
Activating auto-logging. Current session state plus future input saved.
Filename       : /Users/rkern/.ipython/ipython.log
Mode           : backup
Output logging : False
Raw input log  : False
Timestamping   : False
State          : active

In [1]: import sys

In [2]: 'wx' in sys.modules
Out[2]: False

In [3]: import matplotlib

In [4]: 'wx' in sys.modules
Out[4]: False

In [5]: import pylab

In [6]: 'wx' in sys.modules
Out[6]: True

In [7]:
Do you really want to exit ([y]/n)?
^[[A%
                        [~]$ ipython
Activating auto-logging. Current session state plus future input saved.
Filename       : /Users/rkern/.ipython/ipython.log
Mode           : backup
Output logging : False
Raw input log  : False
Timestamping   : False
State          : active

In [1]: import sys

In [2]: 'wx' in sys.modules
Out[2]: False

In [3]: import matplotlib

In [4]: 'wx' in sys.modules
Out[4]: False

In [5]: matplotlib.use('Agg')

In [6]: 'wx' in sys.modules
Out[6]: False

In [7]: import pylab

In [8]: 'wx' in sys.modules
Out[8]: False


-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco