Class TtfMetrics

lib/matplotlib/dviread.py:1027–1045

class TtfMetrics:
    def __init__(self, filename):
        self._face = font_manager.get_font(filename)

    def get_metrics(self, idx):
        # _mul1220 uses a truncating bitshift for compatibility with dvitype.
        # When upem is 2048 the conversion to 12.20 is exact, but when
        # upem is 1000 (e.g. lmroman10-regular.otf) the metrics themselves
        # are not exactly representable as 12.20 fp.  Manual testing via
        # \sbox0{x}\count0=\wd0\typeout{\the\count0} suggests that metrics
        # are rounded (not truncated) after conversion to 12.20 and before
        # multiplication by the scale.
        upem = self._face.units_per_EM  # Usually 2048 or 1000.
        g = self._face.load_glyph(idx, LoadFlags.NO_SCALE)
        return TexMetrics(
            tex_width=round(g.horiAdvance / upem * 2**20),
            tex_height=round(g.horiBearingY / upem * 2**20),
            tex_depth=round((g.height - g.horiBearingY) / upem * 2**20),
        )


PsFont = namedtuple('PsFont', 'texname psname effects encoding filename')