[Matplotlib-users] Bug in matplotlib 1.4.2

[Alex B. <ale...@gm...>]

Dear all,

when plotting scattered data with the "," marker, the data points do not
show up either on screen (Qt4Agg backend) or in saved bitmap images (tested
with png); they do show up if the plot is exported as pdf.

Example code (run in "ipython --pylab" for simplicity):

import numpy as np
a = np.random.standard_normal(500)
b = np.random.standard_normal(500)
plot(a,b,',')
savefig("testplot.png")
savefig("testplot.pdf")

Expected result: Scatter plot of random data points, both on screen and in
saved files.

Actual result: Empty-looking plot both on screen and in png, but plot as
expected in pdf.

System info: Arch linux, Kernel 3.17.6 (and 3.18.6), matplotlib version
1.4.2, Python 3.4.2, IPython 2.3.1., numpy version 1.9.1, Qt4Agg backend.

Related: I posted this to the arch-bugtracker (
https://bugs.archlinux.org/task/43392) and asked on stack overflow whether
anyone else saw this (
http://stackoverflow.com/questions/28112916/python-matplotlib-does-not-display-data-points-bug-or-something-else).
Apparently, the same thing happens in Ubuntu, too.

Hope this is the right place to report this.

Cheers,
Alex

P.S.: I sent the same mail to the list a few weeks ago without registering,
but it was never posted, nor replied to. It might be a good idea not to
suggest at http://matplotlib.org/faq/troubleshooting_faq.html#getting-help
that just sending a mail to the list will achieve anything...