Might be related to #7937?

FWIW, I tried to reproduce this bug (on CentOS 7) with ComicNeue_Light.otf (in the current directory) and the following script

import matplotlib as mpl
import matplotlib.pyplot as plt
from matplotlib.font_manager import FontProperties

plt.style.use('classic')  # to be ~ consistent between mpl versions
fig, ax = plt.subplots(num="mwe")
ax.plot([-5, 0, 5], [0.9, -0.85, 0.7])

# Add some labels with OTF font
fprops = FontProperties(fname='./ComicNeue_Light.otf', weight='light', size=32)
ax.set_xlabel("X-axis testing",fontproperties=fprops)
ax.set_ylabel("Y-axis testing",fontproperties=fprops)
ax.set_title("mpl v" + mpl.__version__, fontproperties=fprops, fontsize=12)
# Adjust tick labels to the OTF font
for label in ax.get_xticklabels() + ax.get_yticklabels():
    label.set_fontproperties(fprops)

plt.tight_layout()
fig.savefig(fig.get_label() + "_" + mpl.__version__ + ".pdf")

What I get is:

• with mpl 1.5.1:
  mwe_1.5.1.pdf

• with mpl 2.0.0rc1:
  mwe_2.0.0rc1.pdf

• with mpl from master (2.0.0.post3337+gc15694b):
  mwe_2.0.0.post3337+gc15694b.pdf

Except the missing “-” glyph, nothing does really looks wrong with 1.5.1, and I get the same text rendering as with 2.0.0rc1. With a recent mpl version from master, the spacing between the glyphs is a bit smaller than with the former mpl versions

Oh I thought it would be difficult to get the Canter font, but actually it was not (freely available here). So the results are similar to the ones with ComicNeue, i.e. I cannot reproduce the bug :/. What I get is:

• with mpl 1.5.1:
  mwe_1.5.1.pdf

• with mpl 2.0.0rc1:
  mwe_2.0.0rc1.pdf

• with mpl from master (2.0.0.post3337+gc15694b):
  mwe_2.0.0.post3337+gc15694b.pdf

Might need to delete the mpl font cache?

I have tried to delete the font cache and that was not successful. I have made a minimal example that continues to work in version 1.5.3 and fail in version 2.0.0. I was not using FontProperties, though.

import matplotlib as mpl
import matplotlib.pyplot as plt

f = {'family':'Canter', 'weight':'light', 'size':20}
mpl.rc('font', **f)

x = [-4,-3,-2,-1.0001,0,1,2,3,4]
y = [0.019,-0.097,-0.343,-0.521,-0.327,-0.362,-0.129,-0.168,-0.078]

fig = plt.figure(figsize=(7.5, 6))
ax = plt.subplot(111)
ax.plot(x, y, linewidth=0.5, alpha=0.2, color='#666666')

ax.set_xlabel('LONG XLABEL TESTING')
ax.set_ylabel('LONGER YLABEL TESTING')

plt.savefig('test.pdf', transparent=True)

NB: I am using FontProperties because Canter fonts are not installed on my OS (and they do not seem to be available in CentOS 7 repositories).

I tried @andermannlab 's example with FontProperties (else I fallback to DejaVu or Bitstream fonts…) and the results are the same as my previous trials. @andermannlab Could you test it using FontProperties please? Just to see if you still have the issue on your side.

I have just tried the FontProperties version and it works (with multiple OpenType fonts, including Canter). Thank you.

Is the long-term solution to transition legacy code to FontProperties?

Honestly I know almost nothing about how fonts are handled in matplotlib, so currently I would simply consider this as a workaround to your problem. Maybe one of the core devs will know more.

It is related to #7937, I've been solving this with a monkeypatch from the patch mentioned in that issue. I'm using otf fonts, and confirm that it works:

import matplotlib.font_manager as fm
from matplotlib.ft2font import FT2Font
def get_font(*args, **kwargs):
    return FT2Font(*args, **kwargs)
fm.get_font = get_font

BUT, the whole darned font gets added to the pdf since subsetting is broken. I run the pdf through ghostscript afterwards, which properly subsets. I use an ipython shell command to do this for me:

def gs(filename):
    command = "gs -o {} -q -dNOPAUSE -sDEVICE=pdfwrite -dBATCH -dSAFER -dPDFSETTINGS=/prepress " \
              "-dAutoRotatePages=/None -dDownsampleColorImages=false -dDownsampleGrayImages=false " \
              "-dDownsampleMonoImages=false -dAutoFilterColorImages=false -dColorImageFilter=/FlateEncode " \
              "-dAutoFilterGrayImages=false -dGrayImageFilter=/FlateEncode {}"
    return command.format(filename[:-4]+'-gs.pdf', filename)
# Run with: !{gs("test")}

Can you try with the fix in #7961 and not the workaround from #7937?

Did subsetting ever work for otf fonts?

That is a @mdboom question, but I think the answer is no.

Ping @andermannlab and @grahamrow; please try with #7961 or I'm going to close this eventually.

Thanks @QuLogic and @jkseppan, this does appear to have solved the issue. Master branch works properly after the #7961 merge, no need for the workaround anymore.

I have a feeling it's a pretty deep rabbit hole, but I might start looking into the subsetting issue.

I'm going to close this since at least one reporter has confirmed it's working.