Package: python3-matplotlib
Version: 3.3.4-1
Severity: normal
Dear Maintainer,
I have experienced intermittent problems with the default TkAgg backend for
python3-matplotlib since I upgraded from buster to bullseye. The problems
go away if you start a program with
import matplotlib as mp
mp.use("Qt5Agg")
to switch to a different backend. I include an example below which triggers
a slew of Tk error messages, although the output seems correct. Sometimes
there are problems with the output as well; I am still trying to produce an
example that produces wrong graphical output but which is simple enough to
submit in a bug report. It appears that to trigger the error messages you
need to
(*) Use plt.ion() as you would in ipython3 (rather than using plt.show() as
you would from the shell).
(*) Use plt.savefig(bbox_inches="tight")
Best wishes
Hugh Pumphrey
##########Begin######example####################
import matplotlib as mp
## Uncomment next line to switch to working Qt5Agg backend
## Default is the same as mp.use("TkAgg")
##mp.use("Qt5Agg")
##mp.use("TkAgg")
import numpy as np
import matplotlib.pyplot as plt
plt.ion()
## plt.close("all")
fig=plt.figure(figsize=(8,4))
plt.clf()
ax=plt.axes()
x=np.linspace(0,10,11)
ax.plot(x,x*x,"ro")
ax.text(5,30,"Test text",fontsize=18)
## plt.show()
## Tk errors get emitted only when you do a plt.savefig()
## with the bbox_inches="tight" option. It is a bit mysterious exactly
## how it is triggered. Use of plt.ion() seems needed.
plt.savefig("test.png",bbox_inches="tight")
#####end######example#########################
-- System Information:
Debian Release: 11.0
APT prefers stable
APT policy: (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 5.10.0-8-amd64 (SMP w/4 CPU threads)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages python3-matplotlib depends on:
ii libc6 2.31-13
ii libfreetype6 2.10.4+dfsg-1
ii libgcc-s1 10.2.1-6
ii libjs-jquery 3.5.1+dfsg+~3.5.5-7
ii libjs-jquery-ui 1.12.1+dfsg-8
ii libstdc++6 10.2.1-6
ii python-matplotlib-data 3.3.4-1
ii python3 3.9.2-3
ii python3-cycler 0.10.0-3
ii python3-dateutil 2.8.1-6
ii python3-kiwisolver 1.3.1-1+b1
ii python3-numpy [python3-numpy-abi9] 1:1.19.5-1
ii python3-pil 8.1.2+dfsg-0.3
ii python3-pyparsing 2.4.7-1
ii python3-six 1.16.0-2
Versions of packages python3-matplotlib recommends:
ii python3-tk 3.9.2-1
Versions of packages python3-matplotlib suggests:
ii dvipng 1.15-1.1+b1
ii ffmpeg 7:4.3.2-0+deb11u2
ii ghostscript 9.53.3~dfsg-7
ii gir1.2-gtk-3.0 3.24.24-4
pn inkscape <none>
ii ipython3 7.20.0-1
ii librsvg2-common 2.50.3+dfsg-1
pn python-matplotlib-doc <none>
pn python3-cairocffi <none>
ii python3-gi 3.38.0-2
pn python3-gi-cairo <none>
pn python3-gobject <none>
ii python3-nose 1.3.7-7
ii python3-pyqt5 5.15.2+dfsg-3
ii python3-scipy 1.6.0-2
ii python3-sip 4.19.25+dfsg-1
ii python3-tornado 6.1.0-1+b1
ii texlive-extra-utils 2020.20210202-3
ii texlive-latex-extra 2020.20210202-3
pn ttf-staypuft <none>
-- no debconf information
