Bug summary

When pgf is used for saving figure and ticks labels above the figure are used a pgf code like \pgftext[x=1in,y=1in,,bottom]{\(\displaystyle {\ensuremath{-}3}\)}% is produced. This places numbers with minus at different y coordinate (higher) than numbers without it. By using base as alignment instead of bottom the issue seems to be resolved. I originally thought that it is a bug in pgf which does not seem to be the case. Moreover, the default placement of the labels on the right side could be improved by alignment at decimal point.

Code for reproduction

import matplotlib
import matplotlib.pyplot as plt
import numpy as np

matplotlib.use('pgf')
matplotlib.rcParams.update({
    'text.usetex'     : True,
    'pgf.texsystem'   : 'pdflatex',
})

fig, ax = plt.subplots(figsize=(4,3))

ax.set_xlim(-1, 1)
ax.set_ylim(-1, 1)

ax.tick_params(left=True, right=True , top=True, bottom=True,
               labeltop=True, labelbottom=True, labelleft=True, labelright=True)

fig.savefig("test.pgf")

Actual outcome

Labels above the plot are not sitting on the same baseline.

(Numbers to the right are aligned suboptimally.)

Expected outcome

Ticks labels (at least the top ones) aligned (sitting on one line).

Additional information

No response

Operating system

Debian Linux

Matplotlib Version

3.7.3

Matplotlib Backend

pgf

Python version

3.9.2

Jupyter version

No response

Installation

Linux package manager