font_manager.py

"""
A module for finding, managing, and using fonts across platforms.

This module provides a single `FontManager` instance that can
be shared across backends and platforms.  The `findfont`
function returns the best TrueType (TTF) font file in the local or
system font path that matches the specified `FontProperties`
instance.  The `FontManager` also handles Adobe Font Metrics
(AFM) font files for use by the PostScript backend.

The design is based on the `W3C Cascading Style Sheet, Level 1 (CSS1)
font specification <http://www.w3.org/TR/1998/REC-CSS2-19980512/>`_.
Future versions may implement the Level 2 or 2.1 specifications.
"""

# KNOWN ISSUES
#
#   - documentation
#   - font variant is untested
#   - font stretch is incomplete
#   - font size is incomplete
#   - default font algorithm needs improvement and testing
#   - setWeights function needs improvement
#   - 'light' is an invalid weight value, remove it.

import dataclasses
from functools import lru_cache
import json
import logging
from numbers import Number
import os
from pathlib import Path
import re
import subprocess
import sys
try:
    import threading
    from threading import Timer
except ImportError:
    import dummy_threading as threading
    from dummy_threading import Timer

import matplotlib as mpl
from matplotlib import _api, afm, cbook, ft2font, rcParams
from matplotlib.fontconfig_pattern import (
    parse_fontconfig_pattern, generate_fontconfig_pattern)
from matplotlib.rcsetup import _validators

_log = logging.getLogger(__name__)

font_scalings = {
    'xx-small': 0.579,
    'x-small':  0.694,
    'small':    0.833,
    'medium':   1.0,
    'large':    1.200,
    'x-large':  1.440,
    'xx-large': 1.728,
    'larger':   1.2,
    'smaller':  0.833,
    None:       1.0,
}
stretch_dict = {
    'ultra-condensed': 100,
    'extra-condensed': 200,
    'condensed':       300,
    'semi-condensed':  400,
    'normal':          500,
    'semi-expanded':   600,
    'semi-extended':   600,
    'expanded':        700,
    'extended':        700,
    'extra-expanded':  800,
    'extra-extended':  800,
    'ultra-expanded':  900,
    'ultra-extended':  900,
}
weight_dict = {
    'ultralight': 100,
    'light':      200,
    'normal':     400,
    'regular':    400,
    'book':       400,
    'medium':     500,
    'roman':      500,
    'semibold':   600,
    'demibold':   600,
    'demi':       600,
    'bold':       700,
    'heavy':      800,
    'extra bold': 800,
    'black':      900,
}
_weight_regexes = [
    # From fontconfig's FcFreeTypeQueryFaceInternal; not the same as
    # weight_dict!
    ("thin", 100),
    ("extralight", 200),
    ("ultralight", 200),
    ("demilight", 350),
    ("semilight", 350),
    ("light", 300),  # Needs to come *after* demi/semilight!
    ("book", 380),
    ("regular", 400),
    ("normal", 400),
    ("medium", 500),
    ("demibold", 600),
    ("demi", 600),
    ("semibold", 600),
    ("extrabold", 800),
    ("superbold", 800),
    ("ultrabold", 800),
    ("bold", 700),  # Needs to come *after* extra/super/ultrabold!
    ("ultrablack", 1000),
    ("superblack", 1000),
    ("extrablack", 1000),
    (r"\bultra", 1000),
    ("black", 900),  # Needs to come *after* ultra/super/extrablack!
    ("heavy", 900),
]
font_family_aliases = {
    'serif',
    'sans-serif',
    'sans serif',
    'cursive',
    'fantasy',
    'monospace',
    'sans',
}


# OS Font paths
try:
    _HOME = Path.home()
except Exception:  # Exceptions thrown by home() are not specified...
    _HOME = Path(os.devnull)  # Just an arbitrary path with no children.
MSFolders = \
    r'Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders'
MSFontDirectories = [
    r'SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts',
    r'SOFTWARE\Microsoft\Windows\CurrentVersion\Fonts']
MSUserFontDirectories = [
    str(_HOME / 'AppData/Local/Microsoft/Windows/Fonts'),
    str(_HOME / 'AppData/Roaming/Microsoft/Windows/Fonts'),
]
X11FontDirectories = [
    # an old standard installation point
    "/usr/X11R6/lib/X11/fonts/TTF/",
    "/usr/X11/lib/X11/fonts",
    # here is the new standard location for fonts
    "/usr/share/fonts/",
    # documented as a good place to install new fonts
    "/usr/local/share/fonts/",
    # common application, not really useful
    "/usr/lib/openoffice/share/fonts/truetype/",
    # user fonts
    str((Path(os.environ.get('XDG_DATA_HOME') or _HOME / ".local/share"))
        / "fonts"),
    str(_HOME / ".fonts"),
]
OSXFontDirectories = [
    "/Library/Fonts/",
    "/Network/Library/Fonts/",
    "/System/Library/Fonts/",
    # fonts installed via MacPorts
    "/opt/local/share/fonts",
    # user fonts
    str(_HOME / "Library/Fonts"),
]


@lru_cache(64)
def _cached_realpath(path):
    return os.path.realpath(path)


def get_fontext_synonyms(fontext):
    """
    Return a list of file extensions extensions that are synonyms for
    the given file extension *fileext*.
    """
    return {
        'afm': ['afm'],
        'otf': ['otf', 'ttc', 'ttf'],
        'ttc': ['otf', 'ttc', 'ttf'],
        'ttf': ['otf', 'ttc', 'ttf'],
    }[fontext]


def list_fonts(directory, extensions):
    """
    Return a list of all fonts matching any of the extensions, found
    recursively under the directory.
    """
    extensions = ["." + ext for ext in extensions]
    return [os.path.join(dirpath, filename)
            # os.walk ignores access errors, unlike Path.glob.
            for dirpath, _, filenames in os.walk(directory)
            for filename in filenames
            if Path(filename).suffix.lower() in extensions]


def win32FontDirectory():
    r"""
    Return the user-specified font directory for Win32.  This is
    looked up from the registry key ::

      \\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders\Fonts

    If the key is not found, ``%WINDIR%\Fonts`` will be returned.
    """
    import winreg
    try:
        with winreg.OpenKey(winreg.HKEY_CURRENT_USER, MSFolders) as user:
            return winreg.QueryValueEx(user, 'Fonts')[0]
    except OSError:
        return os.path.join(os.environ['WINDIR'], 'Fonts')


def _win32RegistryFonts(reg_domain, base_dir):
    r"""
    Search for fonts in the Windows registry.

    Parameters
    ----------
    reg_domain : int
        The top level registry domain (e.g. HKEY_LOCAL_MACHINE).

    base_dir : str
        The path to the folder where the font files are usually located (e.g.
        C:\Windows\Fonts). If only the filename of the font is stored in the
        registry, the absolute path is built relative to this base directory.

    Returns
    -------
    `set`
        `pathlib.Path` objects with the absolute path to the font files found.

    """
    import winreg
    items = set()

    for reg_path in MSFontDirectories:
        try:
            with winreg.OpenKey(reg_domain, reg_path) as local:
                for j in range(winreg.QueryInfoKey(local)[1]):
                    # value may contain the filename of the font or its
                    # absolute path.
                    key, value, tp = winreg.EnumValue(local, j)
                    if not isinstance(value, str):
                        continue
                    try:
                        # If value contains already an absolute path, then it
                        # is not changed further.
                        path = Path(base_dir, value).resolve()
                    except RuntimeError:
                        # Don't fail with invalid entries.
                        continue

                    items.add(path)
        except (OSError, MemoryError):
            continue

    return items


# Also remove _win32RegistryFonts when this is removed.
@_api.deprecated("3.5")
def win32InstalledFonts(directory=None, fontext='ttf'):
    """
    Search for fonts in the specified font directory, or use the
    system directories if none given. Additionally, it is searched for user
    fonts installed. A list of TrueType font filenames are returned by default,
    or AFM fonts if *fontext* == 'afm'.
    """
    import winreg

    if directory is None:
        directory = win32FontDirectory()

    fontext = ['.' + ext for ext in get_fontext_synonyms(fontext)]

    items = set()

    # System fonts
    items.update(_win32RegistryFonts(winreg.HKEY_LOCAL_MACHINE, directory))

    # User fonts
    for userdir in MSUserFontDirectories:
        items.update(_win32RegistryFonts(winreg.HKEY_CURRENT_USER, userdir))

    # Keep only paths with matching file extension.
    return [str(path) for path in items if path.suffix.lower() in fontext]


def _get_win32_installed_fonts():
    """List the font paths known to the Windows registry."""
    import winreg
    items = set()
    # Search and resolve fonts listed in the registry.
    for domain, base_dirs in [
            (winreg.HKEY_LOCAL_MACHINE, [win32FontDirectory()]),  # System.
            (winreg.HKEY_CURRENT_USER, MSUserFontDirectories),  # User.
    ]:
        for base_dir in base_dirs:
            for reg_path in MSFontDirectories:
                try:
                    with winreg.OpenKey(domain, reg_path) as local:
                        for j in range(winreg.QueryInfoKey(local)[1]):
                            # value may contain the filename of the font or its
                            # absolute path.
                            key, value, tp = winreg.EnumValue(local, j)
                            if not isinstance(value, str):
                                continue
                            try:
                                # If value contains already an absolute path,
                                # then it is not changed further.
                                path = Path(base_dir, value).resolve()
                            except RuntimeError:
                                # Don't fail with invalid entries.
                                continue
                            items.add(path)
                except (OSError, MemoryError):
                    continue
    return items


@lru_cache()
def _get_fontconfig_fonts():
    """Cache and list the font paths known to `fc-list`."""
    try:
        if b'--format' not in subprocess.check_output(['fc-list', '--help']):
            _log.warning(  # fontconfig 2.7 implemented --format.
                'Matplotlib needs fontconfig>=2.7 to query system fonts.')
            return []
        out = subprocess.check_output(['fc-list', '--format=%{file}\\n'])
    except (OSError, subprocess.CalledProcessError):
        return []
    return [Path(os.fsdecode(fname)) for fname in out.split(b'\n')]


@_api.deprecated("3.5")
def get_fontconfig_fonts(fontext='ttf'):
    """List font filenames known to `fc-list` having the given extension."""
    fontext = ['.' + ext for ext in get_fontext_synonyms(fontext)]
    return [str(path) for path in _get_fontconfig_fonts()
            if path.suffix.lower() in fontext]


def findSystemFonts(fontpaths=None, fontext='ttf'):
    """
    Search for fonts in the specified font paths.  If no paths are
    given, will use a standard set of system paths, as well as the
    list of fonts tracked by fontconfig if fontconfig is installed and
    available.  A list of TrueType fonts are returned by default with
    AFM fonts as an option.
    """
    fontfiles = set()
    fontexts = get_fontext_synonyms(fontext)

    if fontpaths is None:
        if sys.platform == 'win32':
            installed_fonts = _get_win32_installed_fonts()
            fontpaths = MSUserFontDirectories + [win32FontDirectory()]
        else:
            installed_fonts = _get_fontconfig_fonts()
            if sys.platform == 'darwin':
                fontpaths = [*X11FontDirectories, *OSXFontDirectories]
            else:
                fontpaths = X11FontDirectories
        fontfiles.update(str(path) for path in installed_fonts
                         if path.suffix.lower()[1:] in fontexts)

    elif isinstance(fontpaths, str):
        fontpaths = [fontpaths]

    for path in fontpaths:
        fontfiles.update(map(os.path.abspath, list_fonts(path, fontexts)))

    return [fname for fname in fontfiles if os.path.exists(fname)]


FontEntry = dataclasses.make_dataclass(
    'FontEntry', [
        ('fname', str, dataclasses.field(default='')),
        ('name', str, dataclasses.field(default='')),
        ('style', str, dataclasses.field(default='normal')),
        ('variant', str, dataclasses.field(default='normal')),
        ('weight', str, dataclasses.field(default='normal')),
        ('stretch', str, dataclasses.field(default='normal')),
        ('size', str, dataclasses.field(default='medium')),
    ],
    namespace={
        '__doc__': """
    A class for storing Font properties.

    It is used when populating the font lookup dictionary.
    """})


def ttfFontProperty(font):
    """
    Extract information from a TrueType font file.

    Parameters
    ----------
    font : `.FT2Font`
        The TrueType font file from which information will be extracted.

    Returns
    -------
    `FontEntry`
        The extracted font properties.

    """
    name = font.family_name

    #  Styles are: italic, oblique, and normal (default)

    sfnt = font.get_sfnt()
    mac_key = (1,  # platform: macintosh
               0,  # id: roman
               0)  # langid: english
    ms_key = (3,  # platform: microsoft
              1,  # id: unicode_cs
              0x0409)  # langid: english_united_states

    # These tables are actually mac_roman-encoded, but mac_roman support may be
    # missing in some alternative Python implementations and we are only going
    # to look for ASCII substrings, where any ASCII-compatible encoding works
    # - or big-endian UTF-16, since important Microsoft fonts use that.
    sfnt2 = (sfnt.get((*mac_key, 2), b'').decode('latin-1').lower() or
             sfnt.get((*ms_key, 2), b'').decode('utf_16_be').lower())
    sfnt4 = (sfnt.get((*mac_key, 4), b'').decode('latin-1').lower() or
             sfnt.get((*ms_key, 4), b'').decode('utf_16_be').lower())

    if sfnt4.find('oblique') >= 0:
        style = 'oblique'
    elif sfnt4.find('italic') >= 0:
        style = 'italic'
    elif sfnt2.find('regular') >= 0:
        style = 'normal'
    elif font.style_flags & ft2font.ITALIC:
        style = 'italic'
    else:
        style = 'normal'

    #  Variants are: small-caps and normal (default)

    #  !!!!  Untested
    if name.lower() in ['capitals', 'small-caps']:
        variant = 'small-caps'
    else:
        variant = 'normal'

    # The weight-guessing algorithm is directly translated from fontconfig
    # 2.13.1's FcFreeTypeQueryFaceInternal (fcfreetype.c).
    wws_subfamily = 22
    typographic_subfamily = 16
    font_subfamily = 2
    styles = [
        sfnt.get((*mac_key, wws_subfamily), b'').decode('latin-1'),
        sfnt.get((*mac_key, typographic_subfamily), b'').decode('latin-1'),
        sfnt.get((*mac_key, font_subfamily), b'').decode('latin-1'),
        sfnt.get((*ms_key, wws_subfamily), b'').decode('utf-16-be'),
        sfnt.get((*ms_key, typographic_subfamily), b'').decode('utf-16-be'),
        sfnt.get((*ms_key, font_subfamily), b'').decode('utf-16-be'),
    ]
    styles = [*filter(None, styles)] or [font.style_name]

    def get_weight():  # From fontconfig's FcFreeTypeQueryFaceInternal.
        # OS/2 table weight.
        os2 = font.get_sfnt_table("OS/2")
        if os2 and os2["version"] != 0xffff:
            return os2["usWeightClass"]
        # PostScript font info weight.
        try:
            ps_font_info_weight = (
                font.get_ps_font_info()["weight"].replace(" ", "") or "")
        except ValueError:
            pass
        else:
            for regex, weight in _weight_regexes:
                if re.fullmatch(regex, ps_font_info_weight, re.I):
                    return weight
        # Style name weight.
        for style in styles:
            style = style.replace(" ", "")
            for regex, weight in _weight_regexes:
                if re.search(regex, style, re.I):
                    return weight
        if font.style_flags & ft2font.BOLD:
            return 700  # "bold"
        return 500  # "medium", not "regular"!

    weight = int(get_weight())

    #  Stretch can be absolute and relative
    #  Absolute stretches are: ultra-condensed, extra-condensed, condensed,
    #    semi-condensed, normal, semi-expanded, expanded, extra-expanded,
    #    and ultra-expanded.
    #  Relative stretches are: wider, narrower
    #  Child value is: inherit

    if any(word in sfnt4 for word in ['narrow', 'condensed', 'cond']):
        stretch = 'condensed'
    elif 'demi cond' in sfnt4:
        stretch = 'semi-condensed'
    elif any(word in sfnt4 for word in ['wide', 'expanded', 'extended']):
        stretch = 'expanded'
    else:
        stretch = 'normal'

    #  Sizes can be absolute and relative.
    #  Absolute sizes are: xx-small, x-small, small, medium, large, x-large,
    #    and xx-large.
    #  Relative sizes are: larger, smaller
    #  Length value is an absolute font size, e.g., 12pt
    #  Percentage values are in 'em's.  Most robust specification.

    if not font.scalable:
        raise NotImplementedError("Non-scalable fonts are not supported")
    size = 'scalable'

    return FontEntry(font.fname, name, style, variant, weight, stretch, size)


def afmFontProperty(fontpath, font):
    """
    Extract information from an AFM font file.

    Parameters
    ----------
    font : `.AFM`
        The AFM font file from which information will be extracted.

    Returns
    -------
    `FontEntry`
        The extracted font properties.
    """

    name = font.get_familyname()
    fontname = font.get_fontname().lower()

    #  Styles are: italic, oblique, and normal (default)

    if font.get_angle() != 0 or 'italic' in name.lower():
        style = 'italic'
    elif 'oblique' in name.lower():
        style = 'oblique'
    else:
        style = 'normal'

    #  Variants are: small-caps and normal (default)

    # !!!!  Untested
    if name.lower() in ['capitals', 'small-caps']:
        variant = 'small-caps'
    else:
        variant = 'normal'

    weight = font.get_weight().lower()
    if weight not in weight_dict:
        weight = 'normal'

    #  Stretch can be absolute and relative
    #  Absolute stretches are: ultra-condensed, extra-condensed, condensed,
    #    semi-condensed, normal, semi-expanded, expanded, extra-expanded,
    #    and ultra-expanded.
    #  Relative stretches are: wider, narrower
    #  Child value is: inherit
    if 'demi cond' in fontname:
        stretch = 'semi-condensed'
    elif any(word in fontname for word in ['narrow', 'cond']):
        stretch = 'condensed'
    elif any(word in fontname for word in ['wide', 'expanded', 'extended']):
        stretch = 'expanded'
    else:
        stretch = 'normal'

    #  Sizes can be absolute and relative.
    #  Absolute sizes are: xx-small, x-small, small, medium, large, x-large,
    #    and xx-large.
    #  Relative sizes are: larger, smaller
    #  Length value is an absolute font size, e.g., 12pt
    #  Percentage values are in 'em's.  Most robust specification.

    #  All AFM fonts are apparently scalable.

    size = 'scalable'

    return FontEntry(fontpath, name, style, variant, weight, stretch, size)


class FontProperties:
    """
    A class for storing and manipulating font properties.

    The font properties are the six properties described in the
    `W3C Cascading Style Sheet, Level 1
    <http://www.w3.org/TR/1998/REC-CSS2-19980512/>`_ font
    specification and *math_fontfamily* for math fonts:

    - family: A list of font names in decreasing order of priority.
      The items may include a generic font family name, either
      'sans-serif' (default), 'serif', 'cursive', 'fantasy', or 'monospace'.
      In that case, the actual font to be used will be looked up
      from the associated rcParam.

    - style: Either 'normal' (default), 'italic' or 'oblique'.

    - variant: Either 'normal' (default) or 'small-caps'.

    - stretch: A numeric value in the range 0-1000 or one of
      'ultra-condensed', 'extra-condensed', 'condensed',
      'semi-condensed', 'normal' (default), 'semi-expanded', 'expanded',
      'extra-expanded' or 'ultra-expanded'.

    - weight: A numeric value in the range 0-1000 or one of
      'ultralight', 'light', 'normal' (default), 'regular', 'book', 'medium',
      'roman', 'semibold', 'demibold', 'demi', 'bold', 'heavy',
      'extra bold', 'black'.

    - size: Either an relative value of 'xx-small', 'x-small',
      'small', 'medium', 'large', 'x-large', 'xx-large' or an
      absolute font size, e.g., 10 (default).

    - math_fontfamily: The family of fonts used to render math text; overrides
      :rc:`mathtext.fontset`. Supported values are the same as the ones
      supported by :rc:`mathtext.fontset`: 'dejavusans', 'dejavuserif', 'cm',
      'stix', 'stixsans' and 'custom'.

    Alternatively, a font may be specified using the absolute path to a font
    file, by using the *fname* kwarg.  However, in this case, it is typically
    simpler to just pass the path (as a `pathlib.Path`, not a `str`) to the
    *font* kwarg of the `.Text` object.

    The preferred usage of font sizes is to use the relative values,
    e.g.,  'large', instead of absolute font sizes, e.g., 12.  This
    approach allows all text sizes to be made larger or smaller based
    on the font manager's default font size.

    This class will also accept a fontconfig_ pattern_, if it is the only
    argument provided.  This support does not depend on fontconfig; we are
    merely borrowing its pattern syntax for use here.

    .. _fontconfig: https://www.freedesktop.org/wiki/Software/fontconfig/
    .. _pattern:
       https://www.freedesktop.org/software/fontconfig/fontconfig-user.html

    Note that Matplotlib's internal font manager and fontconfig use a
    different algorithm to lookup fonts, so the results of the same pattern
    may be different in Matplotlib than in other applications that use
    fontconfig.
    """

    def __init__(self, family=None, style=None, variant=None, weight=None,
                 stretch=None, size=None,
                 fname=None,  # if set, it's a hardcoded filename to use
                 math_fontfamily=None):
        self._family = _normalize_font_family(rcParams['font.family'])
        self._slant = rcParams['font.style']
        self._variant = rcParams['font.variant']
        self._weight = rcParams['font.weight']
        self._stretch = rcParams['font.stretch']
        self._size = rcParams['font.size']
        self._file = None
        self.set_math_fontfamily(math_fontfamily)

        if isinstance(family, str):
            # Treat family as a fontconfig pattern if it is the only
            # parameter provided.
            if (style is None and variant is None and weight is None and
                    stretch is None and size is None and fname is None):
                self.set_fontconfig_pattern(family)
                return

        self.set_family(family)
        self.set_style(style)
        self.set_variant(variant)
        self.set_weight(weight)
        self.set_stretch(stretch)
        self.set_file(fname)
        self.set_size(size)

    @classmethod
    def _from_any(cls, arg):
        """
        Generic constructor which can build a `.FontProperties` from any of the
        following:

        - a `.FontProperties`: it is passed through as is;
        - `None`: a `.FontProperties` using rc values is used;
        - an `os.PathLike`: it is used as path to the font file;
        - a `str`: it is parsed as a fontconfig pattern;
        - a `dict`: it is passed as ``**kwargs`` to `.FontProperties`.
        """
        if isinstance(arg, cls):
            return arg
        elif arg is None:
            return cls()
        elif isinstance(arg, os.PathLike):
            return cls(fname=arg)
        elif isinstance(arg, str):
            return cls(arg)
        else:
            return cls(**arg)

    def __hash__(self):
        l = (tuple(self.get_family()),
             self.get_slant(),
             self.get_variant(),
             self.get_weight(),
             self.get_stretch(),
             self.get_size_in_points(),
             self.get_file(),
             self.get_math_fontfamily())
        return hash(l)

    def __eq__(self, other):
        return hash(self) == hash(other)

    def __str__(self):
        return self.get_fontconfig_pattern()

    def get_family(self):
        """
        Return a list of font names that comprise the font family.
        """
        return self._family

    def get_name(self):
        """
        Return the name of the font that best matches the font properties.
        """
        return get_font(findfont(self)).family_name

    def get_style(self):
        """
        Return the font style.  Values are: 'normal', 'italic' or 'oblique'.
        """
        return self._slant
    get_slant = get_style

    def get_variant(self):
        """
        Return the font variant.  Values are: 'normal' or 'small-caps'.
        """
        return self._variant

    def get_weight(self):
        """
        Set the font weight.  Options are: A numeric value in the
        range 0-1000 or one of 'light', 'normal', 'regular', 'book',
        'medium', 'roman', 'semibold', 'demibold', 'demi', 'bold',
        'heavy', 'extra bold', 'black'
        """
        return self._weight

    def get_stretch(self):
        """
        Return the font stretch or width.  Options are: 'ultra-condensed',
        'extra-condensed', 'condensed', 'semi-condensed', 'normal',
        'semi-expanded', 'expanded', 'extra-expanded', 'ultra-expanded'.
        """
        return self._stretch

    def get_size(self):
        """
        Return the font size.
        """
        return self._size

    def get_size_in_points(self):
        return self._size

    def get_file(self):
        """
        Return the filename of the associated font.
        """
        return self._file

    def get_fontconfig_pattern(self):
        """
        Get a fontconfig_ pattern_ suitable for looking up the font as
        specified with fontconfig's ``fc-match`` utility.

        This support does not depend on fontconfig; we are merely borrowing its
        pattern syntax for use here.
        """
        return generate_fontconfig_pattern(self)

    def set_family(self, family):
        """
        Change the font family.  May be either an alias (generic name
        is CSS parlance), such as: 'serif', 'sans-serif', 'cursive',
        'fantasy', or 'monospace', a real font name or a list of real
        font names.  Real font names are not supported when
        :rc:`text.usetex` is `True`.
        """
        if family is None:
            family = rcParams['font.family']
        self._family = _normalize_font_family(family)
    set_name = set_family

    def set_style(self, style):
        """
        Set the font style.  Values are: 'normal', 'italic' or 'oblique'.
        """
        if style is None:
            style = rcParams['font.style']
        _api.check_in_list(['normal', 'italic', 'oblique'], style=style)
        self._slant = style
    set_slant = set_style

    def set_variant(self, variant):
        """
        Set the font variant.  Values are: 'normal' or 'small-caps'.
        """
        if variant is None:
            variant = rcParams['font.variant']
        _api.check_in_list(['normal', 'small-caps'], variant=variant)
        self._variant = variant

    def set_weight(self, weight):
        """
        Set the font weight.  May be either a numeric value in the
        range 0-1000 or one of 'ultralight', 'light', 'normal',
        'regular', 'book', 'medium', 'roman', 'semibold', 'demibold',
        'demi', 'bold', 'heavy', 'extra bold', 'black'
        """
        if weight is None:
            weight = rcParams['font.weight']
        try:
            weight = int(weight)
            if weight < 0 or weight > 1000:
                raise ValueError()
        except ValueError:
            if weight not in weight_dict:
                raise ValueError("weight is invalid")
        self._weight = weight

    def set_stretch(self, stretch):
        """
        Set the font stretch or width.  Options are: 'ultra-condensed',
        'extra-condensed', 'condensed', 'semi-condensed', 'normal',
        'semi-expanded', 'expanded', 'extra-expanded' or
        'ultra-expanded', or a numeric value in the range 0-1000.
        """
        if stretch is None:
            stretch = rcParams['font.stretch']
        try:
            stretch = int(stretch)
            if stretch < 0 or stretch > 1000:
                raise ValueError()
        except ValueError as err:
            if stretch not in stretch_dict:
                raise ValueError("stretch is invalid") from err
        self._stretch = stretch

    def set_size(self, size):
        """
        Set the font size.  Either an relative value of 'xx-small',
        'x-small', 'small', 'medium', 'large', 'x-large', 'xx-large'
        or an absolute font size, e.g., 12.
        """
        if size is None:
            size = rcParams['font.size']
        try:
            size = float(size)
        except ValueError:
            try:
                scale = font_scalings[size]
            except KeyError as err:
                raise ValueError(
                    "Size is invalid. Valid font size are "
                    + ", ".join(map(str, font_scalings))) from err
            else:
                size = scale * FontManager.get_default_size()
        if size < 1.0:
            _log.info('Fontsize %1.2f < 1.0 pt not allowed by FreeType. '
                      'Setting fontsize = 1 pt', size)
            size = 1.0
        self._size = size

    def set_file(self, file):
        """
        Set the filename of the fontfile to use.  In this case, all
        other properties will be ignored.
        """
        self._file = os.fspath(file) if file is not None else None

    def set_fontconfig_pattern(self, pattern):
        """
        Set the properties by parsing a fontconfig_ *pattern*.

        This support does not depend on fontconfig; we are merely borrowing its
        pattern syntax for use here.
        """
        for key, val in parse_fontconfig_pattern(pattern).items():
            if type(val) == list:
                getattr(self, "set_" + key)(val[0])
            else:
                getattr(self, "set_" + key)(val)

    def get_math_fontfamily(self):
        """
        Return the name of the font family used for math text.

        The default font is :rc:`mathtext.fontset`.
        """
        return self._math_fontfamily

    def set_math_fontfamily(self, fontfamily):
        """
        Set the font family for text in math mode.

        If not set explicitly, :rc:`mathtext.fontset` will be used.

        Parameters
        ----------
        fontfamily : str
            The name of the font family.

            Available font families are defined in the
            matplotlibrc.template file
            :ref:`here <customizing-with-matplotlibrc-files>`

        See Also
        --------
        .text.Text.get_math_fontfamily
        """
        if fontfamily is None:
            fontfamily = rcParams['mathtext.fontset']
        else:
            valid_fonts = _validators['mathtext.fontset'].valid.values()
            # _check_in_list() Validates the parameter math_fontfamily as
            # if it were passed to rcParams['mathtext.fontset']
            _api.check_in_list(valid_fonts, math_fontfamily=fontfamily)
        self._math_fontfamily = fontfamily

    def copy(self):
        """Return a copy of self."""
        new = type(self)()
        vars(new).update(vars(self))
        return new


class _JSONEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, FontManager):
            return dict(o.__dict__, __class__='FontManager')
        elif isinstance(o, FontEntry):
            d = dict(o.__dict__, __class__='FontEntry')
            try:
                # Cache paths of fonts shipped with Matplotlib relative to the
                # Matplotlib data path, which helps in the presence of venvs.
                d["fname"] = str(
                    Path(d["fname"]).relative_to(mpl.get_data_path()))
            except ValueError:
                pass
            return d
        else:
            return super().default(o)


def _json_decode(o):
    cls = o.pop('__class__', None)
    if cls is None:
        return o
    elif cls == 'FontManager':
        r = FontManager.__new__(FontManager)
        r.__dict__.update(o)
        return r
    elif cls == 'FontEntry':
        r = FontEntry.__new__(FontEntry)
        r.__dict__.update(o)
        if not os.path.isabs(r.fname):
            r.fname = os.path.join(mpl.get_data_path(), r.fname)
        return r
    else:
        raise ValueError("Don't know how to deserialize __class__=%s" % cls)


def json_dump(data, filename):
    """
    Dump `FontManager` *data* as JSON to the file named *filename*.

    See Also
    --------
    json_load

    Notes
    -----
    File paths that are children of the Matplotlib data path (typically, fonts
    shipped with Matplotlib) are stored relative to that data path (to remain
    valid across virtualenvs).

    This function temporarily locks the output file to prevent multiple
    processes from overwriting one another's output.
    """
    with cbook._lock_path(filename), open(filename, 'w') as fh:
        try:
            json.dump(data, fh, cls=_JSONEncoder, indent=2)
        except OSError as e:
            _log.warning('Could not save font_manager cache {}'.format(e))


def json_load(filename):
    """
    Load a `FontManager` from the JSON file named *filename*.

    See Also
    --------
    json_dump
    """
    with open(filename, 'r') as fh:
        return json.load(fh, object_hook=_json_decode)


def _normalize_font_family(family):
    if isinstance(family, str):
        family = [family]
    return family


class FontManager:
    """
    On import, the `FontManager` singleton instance creates a list of ttf and
    afm fonts and caches their `FontProperties`.  The `FontManager.findfont`
    method does a nearest neighbor search to find the font that most closely
    matches the specification.  If no good enough match is found, the default
    font is returned.
    """
    # Increment this version number whenever the font cache data
    # format or behavior has changed and requires a existing font
    # cache files to be rebuilt.
    __version__ = 330

    def __init__(self, size=None, weight='normal'):
        self._version = self.__version__

        self.__default_weight = weight
        self.default_size = size

        # Create list of font paths.
        paths = [cbook._get_data_path('fonts', subdir)
                 for subdir in ['ttf', 'afm', 'pdfcorefonts']]
        _log.debug('font search path %s', str(paths))

        self.defaultFamily = {
            'ttf': 'DejaVu Sans',
            'afm': 'Helvetica'}

        self.afmlist = []
        self.ttflist = []

        # Delay the warning by 5s.
        timer = Timer(5, lambda: _log.warning(
            'Matplotlib is building the font cache; this may take a moment.'))
        timer.start()
        try:
            for fontext in ["afm", "ttf"]:
                for path in [*findSystemFonts(paths, fontext=fontext),
                             *findSystemFonts(fontext=fontext)]:
                    try:
                        self.addfont(path)
                    except OSError as exc:
                        _log.info("Failed to open font file %s: %s", path, exc)
                    except Exception as exc:
                        _log.info("Failed to extract font properties from %s: "
                                  "%s", path, exc)
        finally:
            timer.cancel()

    def addfont(self, path):
        """
        Cache the properties of the font at *path* to make it available to the
        `FontManager`.  The type of font is inferred from the path suffix.

        Parameters
        ----------
        path : str or path-like
        """
        if Path(path).suffix.lower() == ".afm":
            with open(path, "rb") as fh:
                font = afm.AFM(fh)
            prop = afmFontProperty(path, font)
            self.afmlist.append(prop)
        else:
            font = ft2font.FT2Font(path)
            prop = ttfFontProperty(font)
            self.ttflist.append(prop)
        self._findfont_cached.cache_clear()

    @property
    def defaultFont(self):
        # Lazily evaluated (findfont then caches the result) to avoid including
        # the venv path in the json serialization.
        return {ext: self.findfont(family, fontext=ext)
                for ext, family in self.defaultFamily.items()}

    def get_default_weight(self):
        """
        Return the default font weight.
        """
        return self.__default_weight

    @staticmethod
    def get_default_size():
        """
        Return the default font size.
        """
        return rcParams['font.size']

    def set_default_weight(self, weight):
        """
        Set the default font weight.  The initial value is 'normal'.
        """
        self.__default_weight = weight

    @staticmethod
    def _expand_aliases(family):
        if family in ('sans', 'sans serif'):
            family = 'sans-serif'
        return rcParams['font.' + family]

    # Each of the scoring functions below should return a value between
    # 0.0 (perfect match) and 1.0 (terrible match)
    def score_family(self, families, family2):
        """
        Return a match score between the list of font families in
        *families* and the font family name *family2*.

        An exact match at the head of the list returns 0.0.

        A match further down the list will return between 0 and 1.

        No match will return 1.0.
        """
        if not isinstance(families, (list, tuple)):
            families = [families]
        elif len(families) == 0:
            return 1.0
        family2 = family2.lower()
        step = 1 / len(families)
        for i, family1 in enumerate(families):
            family1 = family1.lower()
            if family1 in font_family_aliases:
                options = [*map(str.lower, self._expand_aliases(family1))]
                if family2 in options:
                    idx = options.index(family2)
                    return (i + (idx / len(options))) * step
            elif family1 == family2:
                # The score should be weighted by where in the
                # list the font was found.
                return i * step
        return 1.0

    def score_style(self, style1, style2):
        """
        Return a match score between *style1* and *style2*.

        An exact match returns 0.0.

        A match between 'italic' and 'oblique' returns 0.1.

        No match returns 1.0.
        """
        if style1 == style2:
            return 0.0
        elif (style1 in ('italic', 'oblique')
              and style2 in ('italic', 'oblique')):
            return 0.1
        return 1.0

    def score_variant(self, variant1, variant2):
        """
        Return a match score between *variant1* and *variant2*.

        An exact match returns 0.0, otherwise 1.0.
        """
        if variant1 == variant2:
            return 0.0
        else:
            return 1.0

    def score_stretch(self, stretch1, stretch2):
        """
        Return a match score between *stretch1* and *stretch2*.

        The result is the absolute value of the difference between the
        CSS numeric values of *stretch1* and *stretch2*, normalized
        between 0.0 and 1.0.
        """
        try:
            stretchval1 = int(stretch1)
        except ValueError:
            stretchval1 = stretch_dict.get(stretch1, 500)
        try:
            stretchval2 = int(stretch2)
        except ValueError:
            stretchval2 = stretch_dict.get(stretch2, 500)
        return abs(stretchval1 - stretchval2) / 1000.0

    def score_weight(self, weight1, weight2):
        """
        Return a match score between *weight1* and *weight2*.

        The result is 0.0 if both weight1 and weight 2 are given as strings
        and have the same value.

        Otherwise, the result is the absolute value of the difference between
        the CSS numeric values of *weight1* and *weight2*, normalized between
        0.05 and 1.0.
        """
        # exact match of the weight names, e.g. weight1 == weight2 == "regular"
        if cbook._str_equal(weight1, weight2):
            return 0.0
        w1 = weight1 if isinstance(weight1, Number) else weight_dict[weight1]
        w2 = weight2 if isinstance(weight2, Number) else weight_dict[weight2]
        return 0.95 * (abs(w1 - w2) / 1000) + 0.05

    def score_size(self, size1, size2):
        """
        Return a match score between *size1* and *size2*.

        If *size2* (the size specified in the font file) is 'scalable', this
        function always returns 0.0, since any font size can be generated.

        Otherwise, the result is the absolute distance between *size1* and
        *size2*, normalized so that the usual range of font sizes (6pt -
        72pt) will lie between 0.0 and 1.0.
        """
        if size2 == 'scalable':
            return 0.0
        # Size value should have already been
        try:
            sizeval1 = float(size1)
        except ValueError:
            sizeval1 = self.default_size * font_scalings[size1]
        try:
            sizeval2 = float(size2)
        except ValueError:
            return 1.0
        return abs(sizeval1 - sizeval2) / 72

    def findfont(self, prop, fontext='ttf', directory=None,
                 fallback_to_default=True, rebuild_if_missing=True):
        """
        Find a font that most closely matches the given font properties.

        Parameters
        ----------
        prop : str or `~matplotlib.font_manager.FontProperties`
            The font properties to search for. This can be either a
            `.FontProperties` object or a string defining a
            `fontconfig patterns`_.

        fontext : {'ttf', 'afm'}, default: 'ttf'
            The extension of the font file:

            - 'ttf': TrueType and OpenType fonts (.ttf, .ttc, .otf)
            - 'afm': Adobe Font Metrics (.afm)

        directory : str, optional
            If given, only search this directory and its subdirectories.

        fallback_to_default : bool
            If True, will fallback to the default font family (usually
            "DejaVu Sans" or "Helvetica") if the first lookup hard-fails.

        rebuild_if_missing : bool
            Whether to rebuild the font cache and search again if the first
            match appears to point to a nonexisting font (i.e., the font cache
            contains outdated entries).

        Returns
        -------
        str
            The filename of the best matching font.

        Notes
        -----
        This performs a nearest neighbor search.  Each font is given a
        similarity score to the target font properties.  The first font with
        the highest score is returned.  If no matches below a certain
        threshold are found, the default font (usually DejaVu Sans) is
        returned.

        The result is cached, so subsequent lookups don't have to
        perform the O(n) nearest neighbor search.

        See the `W3C Cascading Style Sheet, Level 1
        <http://www.w3.org/TR/1998/REC-CSS2-19980512/>`_ documentation
        for a description of the font finding algorithm.

        .. _fontconfig patterns:
           https://www.freedesktop.org/software/fontconfig/fontconfig-user.html
        """
        # Pass the relevant rcParams (and the font manager, as `self`) to
        # _findfont_cached so to prevent using a stale cache entry after an
        # rcParam was changed.
        rc_params = tuple(tuple(rcParams[key]) for key in [
            "font.serif", "font.sans-serif", "font.cursive", "font.fantasy",
            "font.monospace"])
        return self._findfont_cached(
            prop, fontext, directory, fallback_to_default, rebuild_if_missing,
            rc_params)

    @lru_cache()
    def _findfont_cached(self, prop, fontext, directory, fallback_to_default,
                         rebuild_if_missing, rc_params):

        prop = FontProperties._from_any(prop)

        fname = prop.get_file()
        if fname is not None:
            return fname

        if fontext == 'afm':
            fontlist = self.afmlist
        else:
            fontlist = self.ttflist

        best_score = 1e64
        best_font = None

        _log.debug('findfont: Matching %s.', prop)
        for font in fontlist:
            if (directory is not None and
                    Path(directory) not in Path(font.fname).parents):
                continue
            # Matching family should have top priority, so multiply it by 10.
            score = (self.score_family(prop.get_family(), font.name) * 10
                     + self.score_style(prop.get_style(), font.style)
                     + self.score_variant(prop.get_variant(), font.variant)
                     + self.score_weight(prop.get_weight(), font.weight)
                     + self.score_stretch(prop.get_stretch(), font.stretch)
                     + self.score_size(prop.get_size(), font.size))
            _log.debug('findfont: score(%s) = %s', font, score)
            if score < best_score:
                best_score = score
                best_font = font
            if score == 0:
                break

        if best_font is None or best_score >= 10.0:
            if fallback_to_default:
                _log.warning(
                    'findfont: Font family %s not found. Falling back to %s.',
                    prop.get_family(), self.defaultFamily[fontext])
                for family in map(str.lower, prop.get_family()):
                    if family in font_family_aliases:
                        _log.warning(
                            "findfont: Generic family %r not found because "
                            "none of the following families were found: %s",
                            family, ", ".join(self._expand_aliases(family)))
                default_prop = prop.copy()
                default_prop.set_family(self.defaultFamily[fontext])
                return self.findfont(default_prop, fontext, directory,
                                     fallback_to_default=False)
            else:
                raise ValueError(f"Failed to find font {prop}, and fallback "
                                 f"to the default font was disabled")
        else:
            _log.debug('findfont: Matching %s to %s (%r) with score of %f.',
                       prop, best_font.name, best_font.fname, best_score)
            result = best_font.fname

        if not os.path.isfile(result):
            if rebuild_if_missing:
                _log.info(
                    'findfont: Found a missing font file.  Rebuilding cache.')
                new_fm = _load_fontmanager(try_read_cache=False)
                # Replace self by the new fontmanager, because users may have
                # a reference to this specific instance.
                # TODO: _load_fontmanager should really be (used by) a method
                # modifying the instance in place.
                vars(self).update(vars(new_fm))
                return self.findfont(
                    prop, fontext, directory, rebuild_if_missing=False)
            else:
                raise ValueError("No valid font could be found")

        return _cached_realpath(result)


@lru_cache()
def is_opentype_cff_font(filename):
    """
    Return whether the given font is a Postscript Compact Font Format Font
    embedded in an OpenType wrapper.  Used by the PostScript and PDF backends
    that can not subset these fonts.
    """
    if os.path.splitext(filename)[1].lower() == '.otf':
        with open(filename, 'rb') as fd:
            return fd.read(4) == b"OTTO"
    else:
        return False


@lru_cache(64)
def _get_font(filename, hinting_factor, *, _kerning_factor, thread_id):
    return ft2font.FT2Font(
        filename, hinting_factor, _kerning_factor=_kerning_factor)


# FT2Font objects cannot be used across fork()s because they reference the same
# FT_Library object.  While invalidating *all* existing FT2Fonts after a fork
# would be too complicated to be worth it, the main way FT2Fonts get reused is
# via the cache of _get_font, which we can empty upon forking (in Py3.7+).
if hasattr(os, "register_at_fork"):
    os.register_at_fork(after_in_child=_get_font.cache_clear)


def get_font(filename, hinting_factor=None):
    # Resolving the path avoids embedding the font twice in pdf/ps output if a
    # single font is selected using two different relative paths.
    filename = _cached_realpath(filename)
    if hinting_factor is None:
        hinting_factor = rcParams['text.hinting_factor']
    # also key on the thread ID to prevent segfaults with multi-threading
    return _get_font(filename, hinting_factor,
                     _kerning_factor=rcParams['text.kerning_factor'],
                     thread_id=threading.get_ident())


def _load_fontmanager(*, try_read_cache=True):
    fm_path = Path(
        mpl.get_cachedir(), f"fontlist-v{FontManager.__version__}.json")
    if try_read_cache:
        try:
            fm = json_load(fm_path)
        except Exception:
            pass
        else:
            if getattr(fm, "_version", object()) == FontManager.__version__:
                _log.debug("Using fontManager instance from %s", fm_path)
                return fm
    fm = FontManager()
    json_dump(fm, fm_path)
    _log.info("generated new fontManager")
    return fm


fontManager = _load_fontmanager()
findfont = fontManager.findfont