Bug summary

Font weight of x/y axis label is expected to be changed byrcParams["font.weight"] andrcParams["axes.labelweight"], and it works on first plot on the script execution. In same script, however, the updating the rcParams after first plot doesn't take effect. The problem only occurs when the label uses mathtext.

Code for reproduction

I will show two different source.
By running code below, four image will be generated.

importmatplotlib.pyplotaspltplt.rcParams["axes.labelweight"]="normal"plt.rcParams["font.weight"]="normal"plt.figure(constrained_layout=True)plt.ylabel("$aa$")plt.savefig("1-first.png")plt.close()plt.rcParams["axes.labelweight"]="bold"plt.rcParams["font.weight"]="bold"plt.figure(constrained_layout=True)plt.ylabel("$aa$")plt.savefig("1-second.png")plt.close()

importmatplotlib.pyplotaspltplt.rcParams["axes.labelweight"]="bold"plt.rcParams["font.weight"]="bold"plt.figure(constrained_layout=True)plt.ylabel("$aa$")plt.savefig("2-first.png")plt.close()plt.rcParams["axes.labelweight"]="normal"plt.rcParams["font.weight"]="normal"plt.figure(constrained_layout=True)plt.ylabel("$aa$")plt.savefig("2-second.png")plt.close()

Actual outcome

1-first.png

1-second.png

2-first.png

2-second.png

Expected outcome

• 2-second.png is expected to be same as1-first.png
• 1-second.png is expected to be same as2-first.png

Additional information

This is also reproduced by usingplt.rcParams.update() andwith plt.rc_context() instead of directly assigning toplt.rcParams[key].

Operating system

Ubuntu 20.04 on Windows subsystem for Linux

Matplotlib Version

v3.3.3, v3.5.3, HEAD (2171d95)

Matplotlib Backend

agg

Python version

3.8.11

Jupyter version

not using

Installation

pip