Re: [Matplotlib-users] RuntimeError: _image_module::readpng could not open PNG file

[John H. <jdh...@ac...>]

>>>>> "Nils" == Nils Wagner <nw...@me...> writes:

    Nils> Hi all, How can I resolve this problem
    Nils> "/usr/lib/python2.4/site-packages/matplotlib/texmanager.py",
    Nils> line 309, in get_rgba X = readpng(pngfile) RuntimeError:
    Nils> _image_module::readpng could not open PNG file
    Nils> /home/nwagner/.matplotlib/tex.cache/7215ee9c7d9dc229d2921a40e899ec5f_80.png

My guess is that this is a gtk threading problem.  I've seen similar
problems with recent gtk releases.  The problem is that the texmanager
issues os.popen and returns before the command is finished.  We need
a GUI dependent safe way to run system commands that blocks execution
until the system command returns.

See my August thread to the pygtk mailing list

  http://www.daa.com.au/pipermail/pygtk/2005-August/010828.html

David Aitel points to a recipe in his book

  http://www.daa.com.au/pipermail/pygtk/2005-August/010832.html

But this hasn't been implemented yet.  Try flushing your tex cache and
rerunning under tkagg which will fix the problem, I suspect.


Basically we need a backend run_system command for each backend.  

JDH