121 lines
4.6 KiB
Python
121 lines
4.6 KiB
Python
"""
|
|
A module for parsing and generating `fontconfig patterns`_.
|
|
|
|
.. _fontconfig patterns:
|
|
https://www.freedesktop.org/software/fontconfig/fontconfig-user.html
|
|
"""
|
|
|
|
# This class logically belongs in `matplotlib.font_manager`, but placing it
|
|
# there would have created cyclical dependency problems, because it also needs
|
|
# to be available from `matplotlib.rcsetup` (for parsing matplotlibrc files).
|
|
|
|
from functools import lru_cache, partial
|
|
import re
|
|
|
|
from pyparsing import (
|
|
Group, Optional, ParseException, Regex, StringEnd, Suppress, ZeroOrMore)
|
|
|
|
from matplotlib import _api
|
|
|
|
|
|
_family_punc = r'\\\-:,'
|
|
_family_unescape = partial(re.compile(r'\\(?=[%s])' % _family_punc).sub, '')
|
|
_family_escape = partial(re.compile(r'(?=[%s])' % _family_punc).sub, r'\\')
|
|
_value_punc = r'\\=_:,'
|
|
_value_unescape = partial(re.compile(r'\\(?=[%s])' % _value_punc).sub, '')
|
|
_value_escape = partial(re.compile(r'(?=[%s])' % _value_punc).sub, r'\\')
|
|
|
|
|
|
_CONSTANTS = {
|
|
'thin': ('weight', 'light'),
|
|
'extralight': ('weight', 'light'),
|
|
'ultralight': ('weight', 'light'),
|
|
'light': ('weight', 'light'),
|
|
'book': ('weight', 'book'),
|
|
'regular': ('weight', 'regular'),
|
|
'normal': ('weight', 'normal'),
|
|
'medium': ('weight', 'medium'),
|
|
'demibold': ('weight', 'demibold'),
|
|
'semibold': ('weight', 'semibold'),
|
|
'bold': ('weight', 'bold'),
|
|
'extrabold': ('weight', 'extra bold'),
|
|
'black': ('weight', 'black'),
|
|
'heavy': ('weight', 'heavy'),
|
|
'roman': ('slant', 'normal'),
|
|
'italic': ('slant', 'italic'),
|
|
'oblique': ('slant', 'oblique'),
|
|
'ultracondensed': ('width', 'ultra-condensed'),
|
|
'extracondensed': ('width', 'extra-condensed'),
|
|
'condensed': ('width', 'condensed'),
|
|
'semicondensed': ('width', 'semi-condensed'),
|
|
'expanded': ('width', 'expanded'),
|
|
'extraexpanded': ('width', 'extra-expanded'),
|
|
'ultraexpanded': ('width', 'ultra-expanded'),
|
|
}
|
|
|
|
|
|
@lru_cache # The parser instance is a singleton.
|
|
def _make_fontconfig_parser():
|
|
def comma_separated(elem):
|
|
return elem + ZeroOrMore(Suppress(",") + elem)
|
|
|
|
family = Regex(fr"([^{_family_punc}]|(\\[{_family_punc}]))*")
|
|
size = Regex(r"([0-9]+\.?[0-9]*|\.[0-9]+)")
|
|
name = Regex(r"[a-z]+")
|
|
value = Regex(fr"([^{_value_punc}]|(\\[{_value_punc}]))*")
|
|
# replace trailing `| name` by oneOf(_CONSTANTS) in mpl 3.9.
|
|
prop = Group((name + Suppress("=") + comma_separated(value)) | name)
|
|
return (
|
|
Optional(comma_separated(family)("families"))
|
|
+ Optional("-" + comma_separated(size)("sizes"))
|
|
+ ZeroOrMore(":" + prop("properties*"))
|
|
+ StringEnd()
|
|
)
|
|
|
|
|
|
# `parse_fontconfig_pattern` is a bottleneck during the tests because it is
|
|
# repeatedly called when the rcParams are reset (to validate the default
|
|
# fonts). In practice, the cache size doesn't grow beyond a few dozen entries
|
|
# during the test suite.
|
|
@lru_cache
|
|
def parse_fontconfig_pattern(pattern):
|
|
"""
|
|
Parse a fontconfig *pattern* into a dict that can initialize a
|
|
`.font_manager.FontProperties` object.
|
|
"""
|
|
parser = _make_fontconfig_parser()
|
|
try:
|
|
parse = parser.parseString(pattern)
|
|
except ParseException as err:
|
|
# explain becomes a plain method on pyparsing 3 (err.explain(0)).
|
|
raise ValueError("\n" + ParseException.explain(err, 0)) from None
|
|
parser.resetCache()
|
|
props = {}
|
|
if "families" in parse:
|
|
props["family"] = [*map(_family_unescape, parse["families"])]
|
|
if "sizes" in parse:
|
|
props["size"] = [*parse["sizes"]]
|
|
for prop in parse.get("properties", []):
|
|
if len(prop) == 1:
|
|
if prop[0] not in _CONSTANTS:
|
|
_api.warn_deprecated(
|
|
"3.7", message=f"Support for unknown constants "
|
|
f"({prop[0]!r}) is deprecated since %(since)s and "
|
|
f"will be removed %(removal)s.")
|
|
continue
|
|
prop = _CONSTANTS[prop[0]]
|
|
k, *v = prop
|
|
props.setdefault(k, []).extend(map(_value_unescape, v))
|
|
return props
|
|
|
|
|
|
def generate_fontconfig_pattern(d):
|
|
"""Convert a `.FontProperties` to a fontconfig pattern string."""
|
|
kvs = [(k, getattr(d, f"get_{k}")())
|
|
for k in ["style", "variant", "weight", "stretch", "file", "size"]]
|
|
# Families is given first without a leading keyword. Other entries (which
|
|
# are necessarily scalar) are given as key=value, skipping Nones.
|
|
return (",".join(_family_escape(f) for f in d.get_family())
|
|
+ "".join(f":{k}={_value_escape(str(v))}"
|
|
for k, v in kvs if v is not None))
|