206 lines
6.3 KiB
Python
206 lines
6.3 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.fixedTools import fixedToFloat
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from fontTools.misc.textTools import safeEval
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from . import DefaultTable
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import array
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import sys
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import struct
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# Apple's documentation of 'gvar':
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# https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6gvar.html
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#
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# TrueType source code for parsing 'gvar':
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# http://git.savannah.gnu.org/cgit/freetype/freetype2.git/tree/src/truetype/ttgxvar.c
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GVAR_HEADER_FORMAT = b"""
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> # big endian
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version: H
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reserved: H
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axisCount: H
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sharedCoordCount: H
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offsetToCoord: I
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glyphCount: H
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flags: H
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offsetToData: I
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"""
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GVAR_HEADER_SIZE = sstruct.calcsize(GVAR_HEADER_FORMAT)
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TUPLES_SHARE_POINT_NUMBERS = 0x8000
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TUPLE_COUNT_MASK = 0x0fff
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EMBEDDED_TUPLE_COORD = 0x8000
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INTERMEDIATE_TUPLE = 0x4000
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PRIVATE_POINT_NUMBERS = 0x2000
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TUPLE_INDEX_MASK = 0x0fff
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DELTAS_ARE_ZERO = 0x80
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DELTAS_ARE_WORDS = 0x40
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DELTA_RUN_COUNT_MASK = 0x3f
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class table__g_v_a_r(DefaultTable.DefaultTable):
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dependencies = ["fvar", "glyf"]
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def decompile(self, data, ttFont):
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axisTags = [axis.AxisTag for axis in ttFont['fvar'].table.VariationAxis]
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glyphs = ttFont.getGlyphOrder()
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sstruct.unpack(GVAR_HEADER_FORMAT, data[0:GVAR_HEADER_SIZE], self)
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assert len(glyphs) == self.glyphCount
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assert len(axisTags) == self.axisCount
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offsets = self.decompileOffsets_(data[GVAR_HEADER_SIZE:],
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format=(self.flags & 1), glyphCount=self.glyphCount)
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sharedCoords = self.decompileSharedCoords_(axisTags, data)
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self.variations = {}
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for i in xrange(self.glyphCount):
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glyphName = glyphs[i]
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glyph = ttFont["glyf"][glyphName]
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if glyph.isComposite():
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numPoints = len(glyph.components) + 4
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else:
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# Empty glyphs (eg. space, nonmarkingreturn) have no "coordinates" attribute.
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numPoints = len(getattr(glyph, "coordinates", [])) + 4
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gvarData = data[self.offsetToData + offsets[i] : self.offsetToData + offsets[i + 1]]
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self.variations[glyphName] = self.decompileTuples_(numPoints, sharedCoords, axisTags, gvarData)
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def decompileSharedCoords_(self, axisTags, data):
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result = []
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pos = self.offsetToCoord
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stride = len(axisTags) * 2
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for i in xrange(self.sharedCoordCount):
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coord = self.decompileCoord_(axisTags, data[pos:pos+stride])
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result.append(coord)
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pos += stride
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return result
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@staticmethod
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def decompileCoord_(axisTags, data):
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coord = {}
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pos = 0
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for axis in axisTags:
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coord[axis] = fixedToFloat(struct.unpack(b">h", data[pos:pos+2])[0], 14)
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pos += 2
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return coord
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@staticmethod
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def decompileOffsets_(data, format, glyphCount):
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if format == 0:
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# Short format: array of UInt16
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offsets = array.array("H")
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offsetsSize = (glyphCount + 1) * 2
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else:
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# Long format: array of UInt32
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offsets = array.array("I")
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offsetsSize = (glyphCount + 1) * 4
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offsets.fromstring(data[0 : offsetsSize])
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if sys.byteorder != "big":
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offsets.byteswap()
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# In the short format, offsets need to be multiplied by 2.
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# This is not documented in Apple's TrueType specification,
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# but can be inferred from the FreeType implementation, and
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# we could verify it with two sample GX fonts.
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if format == 0:
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offsets = [off * 2 for off in offsets]
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return offsets
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@staticmethod
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def compileOffsets_(offsets):
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"""Packs a list of offsets into a 'gvar' offset table.
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Returns a pair (bytestring, flag). Bytestring is the
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packed offset table. Format indicates whether the table
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uses short (format=0) or long (format=1) integers.
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The returned format should get packed into the flags field
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of the 'gvar' header.
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"""
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assert len(offsets) >= 2
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for i in xrange(1, len(offsets)):
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assert offsets[i - 1] <= offsets[i]
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if max(offsets) <= 0xffff * 2:
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packed = array.array(b"H", [n >> 1 for n in offsets])
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format = 0
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else:
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packed = array.array(b"I", offsets)
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format = 1
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if sys.byteorder != "big":
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packed.byteswap()
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return (packed.tostring(), format)
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def decompileTuples_(self, numPoints, sharedCoords, axisTags, data):
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if len(data) < 4:
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return []
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tuples = []
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flags, offsetToData = struct.unpack(b">HH", data[:4])
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tuplesSharePointNumbers = (flags & TUPLES_SHARE_POINT_NUMBERS) != 0
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assert not tuplesSharePointNumbers # TODO: Implement.
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pos = 4
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dataPos = offsetToData
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for i in xrange(flags & TUPLE_COUNT_MASK):
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dataSize, flags = struct.unpack(b">HH", data[pos:pos+4])
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tupleSize = self.getTupleSize_(flags, self.axisCount)
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tuple = data[pos : pos + tupleSize]
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tupleData = data[dataPos : dataPos + dataSize]
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tuples.append(self.decompileTuple_(numPoints, sharedCoords, axisTags, tuple, tupleData))
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pos += tupleSize
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dataPos += dataSize
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return tuples
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@staticmethod
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def getTupleSize_(flags, axisCount):
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size = 4
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if (flags & EMBEDDED_TUPLE_COORD) != 0:
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size += axisCount * 2
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if (flags & INTERMEDIATE_TUPLE) != 0:
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size += axisCount * 4
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return size
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@staticmethod
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def decompileTuple_(numPoints, sharedCoords, axisTags, data, tupleData):
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flags = struct.unpack(b">H", data[2:4])[0]
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print('***** tuple; flags:%04x' % flags)
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print('data: %s' % ' '.join([x.encode('hex') for x in data]))
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print('tupleData: %s' % ' '.join([x.encode('hex') for x in tupleData]))
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return "TODO"
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@staticmethod
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def decompileDeltas_(numDeltas, data):
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"""(numDeltas, data) --> ([delta, delta, ...], numBytesConsumed)"""
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result = []
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pos = 0
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while len(result) < numDeltas:
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runHeader = ord(data[pos])
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pos += 1
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numDeltasInRun = (runHeader & DELTA_RUN_COUNT_MASK) + 1
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if (runHeader & DELTAS_ARE_ZERO) != 0:
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result.extend([0] * numDeltasInRun)
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elif (runHeader & DELTAS_ARE_WORDS) != 0:
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for i in xrange(numDeltasInRun):
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result.append(struct.unpack(">h", data[pos:pos+2])[0])
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pos += 2
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else:
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for i in xrange(numDeltasInRun):
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result.append(struct.unpack(">b", data[pos])[0])
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pos += 1
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assert len(result) == numDeltas
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return (result, pos)
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def toXML(self, writer, ttFont):
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writer.simpletag("Version", value=self.version)
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writer.newline()
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writer.simpletag("Reserved", value=self.reserved)
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writer.newline()
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class GlyphVariation:
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def __init__(self, axes):
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self.axes = axes
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self.coordinates = []
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def __repr__(self):
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axes = ','.join(sorted(['%s=%s' % (name, value) for (name, value) in self.axes.items()]))
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return '<GlyphVariation %s>' % axes
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