A self-contained example script to highlight the quadmesh bug on OSX using MacOSX backend

mpl_osx_quadmesh_bug.py

import numpy as np
import matplotlib.pyplot as plt

a = np.arange(10)
grid = np.outer(a, a)
plt.pcolormesh(grid)
plt.show()

Traceback

Commit: 8c57e4fe4909815092af470f4a036c80b407382c


Traceback (most recent call last):
  File "/Users/pmarsh/.local/lib/python2.7/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Users/pmarsh/.local/lib/python2.7/site-packages/matplotlib/figure.py", line 927, in draw
    func(*args)
  File "/Users/pmarsh/.local/lib/python2.7/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Users/pmarsh/.local/lib/python2.7/site-packages/matplotlib/axes.py", line 1998, in draw
    a.draw(renderer)
  File "/Users/pmarsh/.local/lib/python2.7/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Users/pmarsh/.local/lib/python2.7/site-packages/matplotlib/collections.py", line 1451, in draw
    self._antialiased, self.get_edgecolors())
  File "/Users/pmarsh/.local/lib/python2.7/site-packages/matplotlib/backends/backend_macosx.py", line 101, in draw_quad_mesh
    showedges)
TypeError: only length-1 arrays can be converted to Python scalars

I'm getting the same error. Any word on what to do about it?

There isn't a current fix right now. The creator of the MacOSX backend is aware of the bug and is working on a solution. Latest estimate I've heard is that it could be a week.