PR Summary

Adding on to the changes from the original PDF PR: #20804, this PR modifies the layout of PS backend to allow embedding multiple fonts.

Currently, Type3 multi-font embedding works fine, however, Type42 fails to display the glyphs from other font, even after the font is embedded (and subsetted).

UPDATE: Using a different font seems to output a good Type42 embedding.

Type3_converted_from_ps.pdf
Type42_converted_from_ps.pdf

^^ Type 3

import matplotlib.pyplot as plt

FONTTYPE = 42    # or 3

plt.rcParams['font.family'] = ['Authentic', 'SimHei']
plt.rcParams['ps.fonttype'] = FONTTYPE
plt.rcParams['font.size'] = 30

plt.figtext(0.18, 0.45, "There are 多个汉字 in between!")
plt.savefig(f"type{FONTTYPE}_fallback.ps")

PR Checklist

• Has pytest style unit tests (and pytest passes).
• Is Flake 8 compliant (run flake8 on changed files to check).
• New features are documented, with examples if plot related.
• Documentation is sphinx and numpydoc compliant (the docs should build without error).
• Conforms to Matplotlib style conventions (install flake8-docstrings and run flake8 --docstring-convention=all).
• New features have an entry in doc/users/next_whats_new/ (follow instructions in README.rst there).
• API changes documented in doc/api/next_api_changes/ (follow instructions in README.rst there).