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[Bug]: Warning: Font Family not found #20850
Description
Bug summary
Usign Latex fonts as recommended here throws a Warning:
findfont: Font family ['serif'] not found. Falling back to DejaVu Sans. findfont: Generic family 'serif' not found because none of the following families were found:
Code for reproduction
import matplotlib.pyplot as plt
plt.rcParams.update({
"font.family": "serif",
# Use LaTeX default serif font.
"font.serif": [],
# Use specific cursive fonts.
"font.cursive": ["Comic Neue", "Comic Sans MS"],
})
plt.figure()
plt.plot([1,2,3,4])
plt.savefig('test.png')
plt.savefig('test.pgf')Actual outcome
The Bug is also visible in your Docs.
https://matplotlib.org/stable/gallery/userdemo/pgf_fonts.html
Expected outcome
No Warning should get thrown everytime
Operating system
Ubuntu
Matplotlib Version
3.4.2
Matplotlib Backend
TkAgg
Python version
3.9.5
Jupyter version
No response
Other libraries
No response
Installation
pip
Conda channel
No response
Activity
FranzForstmayr commented on Aug 17, 2021
Similar to #13139
aitikgupta commented on Aug 29, 2021
Adding documentation tag since the example itself is slightly incorrect..
When you did:
It's really overriding the default Matplotlib serif font-family as an empty list; whereas it really should've been untouched (i.e., the defaults mentioned at: https://matplotlib.org/stable/tutorials/text/usetex.html#sphx-glr-tutorials-text-usetex-py)
I'm not sure why the example was designed in this way.. if the fonts were available you should've got a PGF/PDF with these fonts:
However, with the current example; serif font-family isn't found (because the list is essentially empty!); this is what you get:
Note the missing serif font...
Fix is pretty simple, something like:
import matplotlib.pyplot as plt plt.rcParams.update({ + # Use LaTeX default serif font-family. + # https://matplotlib.org/stable/tutorials/text/usetex.html#sphx-glr-tutorials-text-usetex-py "font.family": "serif", - # Use LaTeX default serif font. - "font.serif": [], # Use specific cursive fonts. "font.cursive": ["Comic Neue", "Comic Sans MS"], })You're welcome to create a PR :)
FranzForstmayr commented on Aug 30, 2021
I'll go for it
Fix matplotlib#20850
urrameu commented on Sep 6, 2021
The empy list is suggested here: https://matplotlib.org/stable/tutorials/text/pgf.html (section "Font specification"). So, either this is correct or that section of the documentation should also be modified. In any case,
Revert "Fix matplotlib#20850"
Fix matplotlib#20850
oscargus commented on Jan 5, 2022
That seems to be correct if the pgf backend is used. However, in https://matplotlib.org/stable/gallery/userdemo/pgf_fonts.html pdf is not used. Adding
import matplotlib as mpl mpl.use("pgf")first in the example file may help. (I'll add a PR.)
oscargus commented on Jan 5, 2022
Wasn't that easy...
The sentence "You can also use the LaTeX default Computer Modern fonts by clearing the lists for rcParams["font.serif"]" is currently not correct since the code:
matplotlib/lib/matplotlib/backends/backend_pgf.py
Lines 47 to 55 in 68d6b79
will use the default Matplotlib font instead.
(Unless pdflatex is used, in which case the fonts are not set.)
So, I've changed this to
path = pathlib.Path(fm.findfont(family), fallback_to_default=False)which then will not set it to the default font. Not sure if it will break anything else.
github-actions commented on Jul 13, 2026
This issue has been marked "inactive" because it has been 365 days since the last comment. If this issue is still present in recent Matplotlib releases, or the feature request is still wanted, please leave a comment and this label will be removed. If there are no updates in another 30 days, this issue will be automatically closed, but you are free to re-open or create a new issue if needed. We value issue reports, and this procedure is meant to help us resurface and prioritize issues that have not been addressed yet, not make them disappear. Thanks for your help!