Class Type1Font

lib/matplotlib/_type1font.py:326–1000

A class representing a Type-1 font, for use by backends. Attributes ---------- parts : tuple A 3-tuple of the cleartext part, the encrypted part, and the finale of zeros. decrypted : bytes The decrypted form of ``parts[1]``. prop : dict[str, Any]

class Type1Font:
    """
    A class representing a Type-1 font, for use by backends.

    Attributes
    ----------
    parts : tuple
        A 3-tuple of the cleartext part, the encrypted part, and the finale of
        zeros.

    decrypted : bytes
        The decrypted form of ``parts[1]``.

    prop : dict[str, Any]
        A dictionary of font properties. Noteworthy keys include:

        - FontName: PostScript name of the font
        - Encoding: dict from numeric codes to glyph names
        - FontMatrix: bytes object encoding a matrix
        - UniqueID: optional font identifier, dropped when modifying the font
        - CharStrings: dict from glyph names to byte code
        - Subrs: array of byte code subroutines
        - OtherSubrs: bytes object encoding some PostScript code
    """
    __slots__ = ('parts', 'decrypted', 'prop', '_pos', '_abbr')
    # the _pos dict contains (begin, end) indices to parts[0] + decrypted
    # so that they can be replaced when transforming the font;
    # but since sometimes a definition appears in both parts[0] and decrypted,
    # _pos[name] is an array of such pairs
    #
    # _abbr maps three standard abbreviations to their particular names in
    # this font (e.g. 'RD' is named '-|' in some fonts)

    def __init__(self, input):
        """
        Initialize a Type-1 font.

        Parameters
        ----------
        input : str or 3-tuple
            Either a pfb file name, or a 3-tuple of already-decoded Type-1
            font `~.Type1Font.parts`.
        """
        if isinstance(input, tuple) and len(input) == 3:
            self.parts = input
        else:
            with open(input, 'rb') as file:
                data = self._read(file)
            self.parts = self._split(data)

        self.decrypted = self._decrypt(self.parts[1], 'eexec')
        self._abbr = {'RD': 'RD', 'ND': 'ND', 'NP': 'NP'}
        self._parse()

    def _read(self, file):
        """Read the font from a file, decoding into usable parts."""
        rawdata = file.read()
        if not rawdata.startswith(b'\x80'):