How to enable Matplotlib within virtual environment?

[tetris_theMovie]

Cross posted from Linux Mint forum. So far I am unable to get Matplotlib to function inside the virtual environment; LMDE 6, AMD64.

Let's suppose there is the file '~/path/file.py', and there is the virtual environment 'vEnv'. The contents of file.py is:

import matplotlib.pyplot as plt
import numpy as np

# Data for plotting
t = np.arange(0.0, 2.0, 0.01)
s = 1 + np.sin(2 * np.pi * t)

fig, ax = plt.subplots()
ax.plot(t, s)

ax.set(xlabel='time (s)', ylabel='voltage (mV)',
       title='About as simple as it gets, folks')
ax.grid()

fig.savefig("test.png")
plt.show()

At Linux terminal there be a command, it gives error output:

Output:
(vEnv) user@host:~$ python3 -i ~/path/file.py 

Error:
qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: vnc, vkkhrdisplay, wayland, offscreen, minimalegl, eglfs, linuxfb, xcb, minimal, wayland-egl.

Aborted (core dumped)

Here is a summary of the virtual environment:

Output:
(vEnv) user@host:~$ python3 -m pip list -v
Package            Version     Location                                     Installer
------------------ ----------- -------------------------------------------- ---------
certifi            2024.8.30   /home/user/vEnv/lib/python3.11/site-packages pip
charset-normalizer 3.3.2       /home/user/vEnv/lib/python3.11/site-packages pip
contourpy          1.3.0       /home/user/vEnv/lib/python3.11/site-packages pip
cycler             0.12.1      /home/user/vEnv/lib/python3.11/site-packages pip
fonttools          4.53.1      /home/user/vEnv/lib/python3.11/site-packages pip
idna               3.10        /home/user/vEnv/lib/python3.11/site-packages pip
kiwisolver         1.4.7       /home/user/vEnv/lib/python3.11/site-packages pip
lorem              0.1.1       /home/user/vEnv/lib/python3.11/site-packages pip
matplotlib         3.9.2       /home/user/vEnv/lib/python3.11/site-packages pip
meson              1.5.0       /home/user/vEnv/lib/python3.11/site-packages pip
mpmath             1.3.0       /home/user/vEnv/lib/python3.11/site-packages pip
numpy              2.1.0       /home/user/vEnv/lib/python3.11/site-packages pip
packaging          24.1        /home/user/vEnv/lib/python3.11/site-packages pip
pandas             2.2.3       /home/user/vEnv/lib/python3.11/site-packages pip
pillow             10.4.0      /home/user/vEnv/lib/python3.11/site-packages pip
pip                23.0.1      /home/user/vEnv/lib/python3.11/site-packages pip
platformdirs       4.3.6       /home/user/vEnv/lib/python3.11/site-packages pip
pooch              1.8.2       /home/user/vEnv/lib/python3.11/site-packages pip
pyparsing          3.1.4       /home/user/vEnv/lib/python3.11/site-packages pip
PyQt6              6.7.1       /home/user/vEnv/lib/python3.11/site-packages pip
PyQt6-Qt6          6.7.3       /home/user/vEnv/lib/python3.11/site-packages pip
PyQt6_sip          13.8.0      /home/user/vEnv/lib/python3.11/site-packages pip
python-dateutil    2.9.0.post0 /home/user/vEnv/lib/python3.11/site-packages pip
pytz               2024.2      /home/user/vEnv/lib/python3.11/site-packages pip
pyvista            0.44.1      /home/user/vEnv/lib/python3.11/site-packages pip
requests           2.32.3      /home/user/vEnv/lib/python3.11/site-packages pip
scooby             0.10.0      /home/user/vEnv/lib/python3.11/site-packages pip
setuptools         66.1.1      /home/user/vEnv/lib/python3.11/site-packages pip
six                1.16.0      /home/user/vEnv/lib/python3.11/site-packages pip
sympy              1.13.3      /home/user/vEnv/lib/python3.11/site-packages pip
typing_extensions  4.12.2      /home/user/vEnv/lib/python3.11/site-packages pip
tzdata             2024.2      /home/user/vEnv/lib/python3.11/site-packages pip
urllib3            2.2.3       /home/user/vEnv/lib/python3.11/site-packages pip
vtk                9.3.1       /home/user/vEnv/lib/python3.11/site-packages pip

My question is: what is a good and simple way to get Matplotlib functionality within said virtual environment?

[christie2]

How can I diagnose the specific error message I receive when trying to execute the script in the terminal, and what common issues should I look for?