11d3770ca6
Because I could not find any fonts with “dlng” (design languages) or “slng” (supported languages) sub-tables, these are not implemented yet. We could easily implement them according to spec, but it is unclear to what extent the spec is matching reality.
94 lines
3.4 KiB
Python
94 lines
3.4 KiB
Python
from __future__ import print_function, division, absolute_import
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from fontTools.misc.py23 import *
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from fontTools.misc import sstruct
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from fontTools.misc.textTools import readHex
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from fontTools.ttLib import TTLibError
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from . import DefaultTable
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# Apple's documentation of 'meta':
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# https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6meta.html
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META_HEADER_FORMAT = """
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> # big endian
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version: L
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flags: L
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dataOffset: L
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numDataMaps: L
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"""
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# According to Apple's spec, the dataMaps entries contain a dataOffset
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# that is documented as "Offset from the beginning of the data section
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# to the data for this tag". However, this is *not* the case with
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# the fonts that Apple ships pre-installed on MacOS X Yosemite 10.10.4,
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# and it also does not reflect how Apple's ftxdumperfuser tool is parsing
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# the 'meta' table (tested ftxdumperfuser build 330, FontToolbox.framework
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# build 187). Instead of what is claimed in the spec, the data maps contain
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# a dataOffset relative to the very beginning of the 'meta' table.
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# The dataOffset field of the 'meta' header apparently gets ignored.
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DATA_MAP_FORMAT = """
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> # big endian
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tag: 4s
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dataOffset: L
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dataLength: L
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"""
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class table__m_e_t_a(DefaultTable.DefaultTable):
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def __init__(self, tag="meta"):
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DefaultTable.DefaultTable.__init__(self, tag)
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self.data = {}
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def decompile(self, data, ttFont):
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headerSize = sstruct.calcsize(META_HEADER_FORMAT)
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header = sstruct.unpack(META_HEADER_FORMAT, data[0 : headerSize])
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if header["version"] != 1:
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raise TTLibError("unsupported 'meta' version %d" %
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header["version"])
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dataMapSize = sstruct.calcsize(DATA_MAP_FORMAT)
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for i in range(header["numDataMaps"]):
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dataMapOffset = headerSize + i * dataMapSize
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dataMap = sstruct.unpack(
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DATA_MAP_FORMAT,
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data[dataMapOffset : dataMapOffset + dataMapSize])
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tag = dataMap["tag"]
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offset = dataMap["dataOffset"]
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self.data[tag] = data[offset : offset + dataMap["dataLength"]]
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def compile(self, ttFont):
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keys = sorted(self.data.keys())
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headerSize = sstruct.calcsize(META_HEADER_FORMAT)
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dataOffset = headerSize + len(keys) * sstruct.calcsize(DATA_MAP_FORMAT)
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header = sstruct.pack(META_HEADER_FORMAT, {
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"version": 1,
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"flags": 0,
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"dataOffset": dataOffset,
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"numDataMaps": len(keys)
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})
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dataMaps = []
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dataBlocks = []
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for tag in keys:
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data = self.data[tag]
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dataMaps.append(sstruct.pack(DATA_MAP_FORMAT, {
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"tag": tag,
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"dataOffset": dataOffset,
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"dataLength": len(data)
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}))
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dataBlocks.append(data)
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dataOffset += len(data)
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return bytesjoin([header] + dataMaps + dataBlocks)
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def toXML(self, writer, ttFont, progress=None):
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for tag in sorted(self.data.keys()):
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writer.begintag("hexdata", tag=tag)
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writer.newline()
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writer.dumphex(self.data[tag])
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writer.endtag("hexdata")
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writer.newline()
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def fromXML(self, name, attrs, content, ttFont):
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if name == "hexdata":
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self.data[attrs["tag"]] = readHex(content)
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else:
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raise TTLibError("can't handle '%s' element" % name)
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