Setting arbitrary fonts in matplotlib

plt_font_manager.py

import matplotlib.pyplot as plt
import matplotlib.font_manager as plt_fm

class PltFontManager:
    """
    Sometimes matplotlib finds the system font paths, but setting them can
    still be challenging due to using the wrong name or matplotlib complaining
    about missing elements.

    This manager static class is intended to aid with that, by facilitating
    the found paths and their corresponding font names, and providing a
    ``set_font`` convenience method that will provide the allowed names if
    the given one didn't work out.
    """
    @staticmethod
    def get_font_paths():
        """
        :returns: List of paths to the fonts found by matplotlib in the system.
        """
        result = plt_fm.findSystemFonts()
        return result

    @classmethod
    def get_font_names(cls):
        """
        :returns: A tuple ``(fontnames, errors)``, where ``fontnames`` is a
          list with the valid font names that can be used, and ``errors`` is
          a dictionary in the form ``font_name: error`` containing fonts that
          couldn't be successfully loaded.
        """
        fpaths = cls.get_font_paths()
        fnames = set()
        errors = {}
        for fp in fpaths:
            try:
                fname = plt_fm.FontProperties(fname=fp).get_name()
                fnames.add(fname)
            except Exception as e:
                errors[fp] = e
        #
        return fnames, errors

    @classmethod
    def set_font(cls, font_name="Liberation Mono"):
        """
        :param font_name: A valid font name as the ones retrieved by the
          ``get_font_names`` method

        This method attempts to set the given font. If that is not possible,
        it will inform the user and provide a list of available fonts.
        """
        try:
            plt_fm.findfont(font_name, fallback_to_default=False)
            plt.rcParams["font.family"] = font_name
        except ValueError as ve:
            print(ve)
            print("Available fonts:")
            print(sorted(cls.get_font_names()[0]))