fonttools/Lib/fontTools/ttLib/tables/BitmapGlyphMetrics.py

# Since bitmap glyph metrics are shared between EBLC and EBDT
# this class gets its own python file.
from fontTools.misc import sstruct
from fontTools.misc.textTools import safeEval
import logging


log = logging.getLogger(__name__)

bigGlyphMetricsFormat = """
  > # big endian
  height:       B
  width:        B
  horiBearingX: b
  horiBearingY: b
  horiAdvance:  B
  vertBearingX: b
  vertBearingY: b
  vertAdvance:  B
"""

smallGlyphMetricsFormat = """
  > # big endian
  height:   B
  width:    B
  BearingX: b
  BearingY: b
  Advance:  B
"""


class BitmapGlyphMetrics(object):
    def toXML(self, writer, ttFont):
        writer.begintag(self.__class__.__name__)
        writer.newline()
        for metricName in sstruct.getformat(self.__class__.binaryFormat)[1]:
            writer.simpletag(metricName, value=getattr(self, metricName))
            writer.newline()
        writer.endtag(self.__class__.__name__)
        writer.newline()

    def fromXML(self, name, attrs, content, ttFont):
        metricNames = set(sstruct.getformat(self.__class__.binaryFormat)[1])
        for element in content:
            if not isinstance(element, tuple):
                continue
            name, attrs, content = element
            # Make sure this is a metric that is needed by GlyphMetrics.
            if name in metricNames:
                vars(self)[name] = safeEval(attrs["value"])
            else:
                log.warning(
                    "unknown name '%s' being ignored in %s.",
                    name,
                    self.__class__.__name__,
                )


class BigGlyphMetrics(BitmapGlyphMetrics):
    binaryFormat = bigGlyphMetricsFormat


class SmallGlyphMetrics(BitmapGlyphMetrics):
    binaryFormat = smallGlyphMetricsFormat