macosx backend: set_linewidth requires a float

[mdboom]

Running sankey_demo_basics.py:

Traceback (most recent call last):
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/figure.py", line 884, in draw
    func(*args)
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/axes.py", line 1983, in draw
    a.draw(renderer)
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/patches.py", line 385, in draw
    gc.set_linewidth(lw)
TypeError: a float is required
Traceback (most recent call last):
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/figure.py", line 884, in draw
    func(*args)
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/axes.py", line 1983, in draw
    a.draw(renderer)
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Library/Frameworks/EPD64.framework/Versions/7.2/lib/python2.7/site-packages/matplotlib/patches.py", line 385, in draw
    gc.set_linewidth(lw)
TypeError: a float is required

[mdehoon]

The problem seems to originate from this line in lib/matplotlib/sankey.py:

    patch = PathPatch(Path(vertices, codes),
                      fc=kwargs.pop('fc', kwargs.pop('facecolor',
                                    '#bfd1d4')), # Custom defaults
                      lw=kwargs.pop('lw', kwargs.pop('linewidth',
                                    '0.5')),
                      **kwargs)

Note that the linewidth is set to the string '0.5' rather than the float 0.5. gc.set_linewidth is then called with the string '0.5' as the argument, which triggers the error. If I replace '0.5' by 0.5, the example runs fine with the MacOSX backend.

Is there a reason why this needs to be a string here? I would think that in general gc.set_linewidth should only accept floats and ints.

[mdboom]

Ah. Thanks for looking into this. I will fix the sankey.py demo.

[sboeschhuawei]

Which version is this fixed in ? I am seeing this error now (2015) and still on os/x

Traceback (most recent call last):
File "/usr/local/lib/python2.7/site-packages/matplotlib/artist.py", line 59, in draw_wrapper
draw(artist, renderer, _args, *_kwargs)
File "/usr/local/lib/python2.7/site-packages/matplotlib/figure.py", line 1085, in draw
func(_args)
File "/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/mpl_toolkits/axes_grid1/parasite_axes.py", line 295, in draw
self._get_base_axes_attr("draw")(self, renderer)
File "/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/mpl_toolkits/axisartist/axislines.py", line 778, in draw
super(Axes, self).draw(renderer, inframe)
File "/usr/local/lib/python2.7/site-packages/matplotlib/artist.py", line 59, in draw_wrapper
draw(artist, renderer, *args, *_kwargs)
File "/usr/local/lib/python2.7/site-packages/matplotlib/axes/_base.py", line 2110, in draw
a.draw(renderer)
File "/usr/local/lib/python2.7/site-packages/matplotlib/artist.py", line 59, in draw_wrapper
draw(artist, renderer, _args, *_kwargs)
File "/usr/local/lib/python2.7/site-packages/matplotlib/lines.py", line 728, in draw
gc.set_linewidth(self._markeredgewidth)
TypeError: a float is required

[jenshnielsen]

@sboeschhuawei Exactly which code does you run when you see this issue?

The issue here was that one of the demos was passing the line width as a string. The fix is pass it as a number. It it possible that your code passes a line width as a string?

[sboeschhuawei]

This response came a bit later and I do not have the dev setup immediately available. I was not calling any low level api's. I will update again when this happens anew.

[josepablog]

Is this fixed in the current release? I can still reproduce the error...

[mdehoon]

@josepablog I can't reproduce this with sankey_demo_basics.py. Which code did you use to reproduce the error?