Re: [Matplotlib-users] Bug with pcolorfast

[Eric F. <ef...@ha...>]

G Jones wrote:
> Hello,
> Executing the following commands from ipython --pylab produces the error 
> below:
> 
> ax = subplot(111)
> ax.pcolorfast(randn(100,100))
> ax.set_xlim(2000,2001)
> draw()
> 
> I ran into the error in a more complicated script, but this seems to be 
> a simple example to reproduce it.
> I notice if I instead use:
> ax.set_xlim(400,500)
> draw()
> I get the expected behavior, so it seems to be a combination of the 
> width being smaller than the extent, and the drawing area being off screen.

Thank you.  The error is actually coming from the image code, which 
pcolorfast is using in this case, and it can be reproduced with imshow.
It is now fixed in the maintenance branch, and the fix will be 
propagated to the trunk shortly.

Eric

> 
> My matplot lib info is
> 
> In [19]: matplotlib.get_backend()
> Out[19]: 'Qt4Agg'
> 
> In [20]: matplotlib.__version__
> Out[20]: '1.0.svn'
> 
> This version was built from SVN just a couple of days ago.
> 
> Error traceback:
> 
> 
> ---------------------------------------------------------------------------
> ZeroDivisionError                         Traceback (most recent call last)
> 
> /home/obs/workspace/backend/<ipython console> in <module>()
> 
> /usr/local/lib/python2.6/dist-packages/matplotlib/pyplot.pyc in draw()
>     350 def draw():
>     351     'redraw the current figure'
> --> 352     get_current_fig_manager().canvas.draw()
>     353
>     354 def savefig(*args, **kwargs):
> 
> /usr/local/lib/python2.6/dist-packages/matplotlib/backends/backend_qt4agg.pyc 
> in draw(self)
>     128         if DEBUG: print "FigureCanvasQtAgg.draw", self
>     129         self.replot = True
> --> 130         FigureCanvasAgg.draw(self)
>     131         self.update()
>     132
> 
> /usr/local/lib/python2.6/dist-packages/matplotlib/backends/backend_agg.pyc 
> in draw(self)
>     313
>     314         self.renderer = self.get_renderer()
> --> 315         self.figure.draw(self.renderer)
>     316
>     317     def get_renderer(self):
> 
> /usr/local/lib/python2.6/dist-packages/matplotlib/artist.pyc in 
> draw_wrapper(artist, renderer, *kl)
>      44     def draw_wrapper(artist, renderer, *kl):
>      45         before(artist, renderer)
> ---> 46         draw(artist, renderer, *kl)
>      47         after(artist, renderer)
>      48
> 
> /usr/local/lib/python2.6/dist-packages/matplotlib/figure.pyc in 
> draw(self, renderer)
>     773
>     774         # render the axes
> 
> --> 775         for a in self.axes: a.draw(renderer)
>     776
>     777         # render the figure text
> 
> 
> /usr/local/lib/python2.6/dist-packages/matplotlib/artist.pyc in 
> draw_wrapper(artist, renderer, *kl)
>      44     def draw_wrapper(artist, renderer, *kl):
>      45         before(artist, renderer)
> ---> 46         draw(artist, renderer, *kl)
>      47         after(artist, renderer)
>      48
> 
> /usr/local/lib/python2.6/dist-packages/matplotlib/axes.pyc in draw(self, 
> renderer, inframe)
>    1685         if len(self.images)<=1 or 
> renderer.option_image_nocomposite():
>    1686             for im in self.images:
> -> 1687                 im.draw(renderer)
>    1688         else:
>    1689             # make a composite image blending alpha
> 
> 
> /usr/local/lib/python2.6/dist-packages/matplotlib/artist.pyc in 
> draw_wrapper(artist, renderer, *kl)
>      44     def draw_wrapper(artist, renderer, *kl):
>      45         before(artist, renderer)
> ---> 46         draw(artist, renderer, *kl)
>      47         after(artist, renderer)
>      48
> 
> /usr/local/lib/python2.6/dist-packages/matplotlib/image.pyc in 
> draw(self, renderer, *args, **kwargs)
>     134             self.axes.get_yscale() != 'linear'):
>     135             warnings.warn("Images are not supported on 
> non-linear axes.")
> --> 136         im = self.make_image(renderer.get_image_magnification())
>     137         im._url = self.get_url()
>     138         l, b, widthDisplay, heightDisplay = self.axes.bbox.bounds
> 
> /usr/local/lib/python2.6/dist-packages/matplotlib/image.pyc in 
> make_image(self, magnification)
>     424
>     425         # resize viewport to display
> 
> --> 426         rx = widthDisplay / numcols
>     427         ry = heightDisplay  / numrows
>     428         im.apply_scaling(rx*sx, ry*sy)
> 
> ZeroDivisionError: float division
> 
> 
> ------------------------------------------------------------------------
> 
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