Traceback (most recent call last):
  File "/home/weber/Promotion/svn/report/MainWindow.py", line 218, in onExport
    figure.savefig(tmp, format=format, transparent=True)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/figure.py", line 1160, in savefig
    self.canvas.print_figure(*args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/backends/backend_wxagg.py", line 100, in print_figure
    FigureCanvasAgg.print_figure(self, filename, *args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/backend_bases.py", line 1963, in print_figure
    **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/backend_bases.py", line 1758, in print_svg
    return svg.print_svg(*args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/backends/backend_svg.py", line 870, in print_svg
    return self._print_svg(filename, svgwriter, fh_to_close, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/backends/backend_svg.py", line 905, in _print_svg
    self.figure.draw(renderer)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/figure.py", line 874, in draw
    func(*args)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/axes.py", line 1954, in draw
    a.draw(renderer)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/axis.py", line 986, in draw
    tick.draw(renderer)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/axis.py", line 234, in draw
    self.label1.draw(renderer)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/text.py", line 591, in draw
    ismath=ismath)
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/backends/backend_svg.py", line 676, in draw_text
    write(svg)
  File "/usr/lib/python2.6/codecs.py", line 801, in write
    data, bytesdecoded = self.decode(data, self.errors)
  File "/usr/lib/python2.6/encodings/utf_8.py", line 16, in decode
    return codecs.utf_8_decode(input, errors, True)
UnicodeEncodeError: 'ascii' codec can't encode character u'\u2212' in position 155: ordinal not in range(128)