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ttfonts.py
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ttfonts.py
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# ******************************************************************************
# TTFontFile class
#
# This class is based on The ReportLab Open Source PDF library
# written in Python - http://www.reportlab.com/software/opensource/
# together with ideas from the OpenOffice source code and others.
#
# Version: 1.04
# Date: 2011-09-18
# Author: Ian Back <ianb@bpm1.com>
# License: LGPL
# Copyright (c) Ian Back, 2010
# Ported to Python 2.7 by Mariano Reingart (reingart@gmail.com) on 2012
# This header must be retained in any redistribution or
# modification of the file.
#
# ******************************************************************************
import re
import warnings
from struct import error as StructError, pack, unpack
from .util import b, substr
# Define the value used in the "head" table of a created TTF file
# 0x74727565 "true" for Mac
# 0x00010000 for Windows
# Either seems to work for a font embedded in a PDF file
# when read by Adobe Reader on a Windows PC(!)
_TTF_MAC_HEADER = False
# TrueType Font Glyph operators
GF_WORDS = 1 << 0
GF_SCALE = 1 << 3
GF_MORE = 1 << 5
GF_XYSCALE = 1 << 6
GF_TWOBYTWO = 1 << 7
def sub32(x, y):
xlo = x[1]
xhi = x[0]
ylo = y[1]
yhi = y[0]
if ylo > xlo:
xlo += 1 << 16
yhi += 1
reslo = xlo - ylo
if yhi > xhi:
xhi += 1 << 16
reshi = xhi - yhi
reshi = reshi & 0xFFFF
return reshi, reslo
def calcChecksum(data):
if len(data) % 4:
data += b("\0") * (4 - (len(data) % 4))
hi = 0x0000
lo = 0x0000
for i in range(0, len(data), 4):
hi += (data[i] << 8) + data[i + 1]
lo += (data[i + 2] << 8) + data[i + 3]
hi += lo >> 16
lo &= 0xFFFF
hi &= 0xFFFF
return hi, lo
class TTFontFile:
def __init__(self):
# Maximum size of glyph table to read in as string
# (otherwise reads each glyph from file)
self.maxStrLenRead = 200000
def getMetrics(self, file):
self.filename = file
with open(file, "rb") as self.fh:
self._pos = 0
self.charWidths = []
self.glyphPos = {}
self.charToGlyph = {}
self.tables = {}
self.otables = {}
self.ascent = 0
self.descent = 0
self.version = version = self.read_ulong()
if version == 0x4F54544F:
raise RuntimeError("Postscript outlines are not supported")
if version == 0x74746366:
raise RuntimeError("ERROR - TrueType Fonts Collections not supported")
if version not in (0x00010000, 0x74727565):
raise RuntimeError(f"Not a TrueType font: version=0x{version:x}")
self.readTableDirectory()
self.extractInfo()
def readTableDirectory(
self,
):
self.numTables = self.read_ushort()
self.searchRange = self.read_ushort()
self.entrySelector = self.read_ushort()
self.rangeShift = self.read_ushort()
self.tables = {}
for _ in range(self.numTables):
record = {
"tag": self.read_tag(),
"checksum": (self.read_ushort(), self.read_ushort()),
"offset": self.read_ulong(),
"length": self.read_ulong(),
}
self.tables[record["tag"]] = record
def get_table_pos(self, tag):
offset = self.tables[tag]["offset"]
length = self.tables[tag]["length"]
return offset, length
def seek(self, pos):
self._pos = pos
self.fh.seek(self._pos)
def skip(self, delta):
self._pos = self._pos + delta
self.fh.seek(self._pos)
def seek_table(self, tag, offset_in_table=0):
tpos = self.get_table_pos(tag)
self._pos = tpos[0] + offset_in_table
self.fh.seek(self._pos)
return self._pos
def read_tag(self):
self._pos += 4
return self.fh.read(4).decode("latin1")
def read_short(self):
self._pos += 2
s = self.fh.read(2)
a = (s[0] << 8) + s[1]
if a & (1 << 15):
a = a - (1 << 16)
return a
def read_ushort(self):
self._pos += 2
s = self.fh.read(2)
return (s[0] << 8) + s[1]
def read_ulong(self):
self._pos += 4
s = self.fh.read(4)
# if large uInt32 as an integer, PHP converts it to -ve
return s[0] * 16777216 + (s[1] << 16) + (s[2] << 8) + s[3] # 16777216 = 1<<24
def get_ushort(self, pos):
self.fh.seek(pos)
s = self.fh.read(2)
return (s[0] << 8) + s[1]
@staticmethod
def splice(stream, offset, value):
return substr(stream, 0, offset) + value + substr(stream, offset + len(value))
def _set_ushort(self, stream, offset, value):
up = pack(">H", value)
return self.splice(stream, offset, up)
def get_chunk(self, pos, length):
self.fh.seek(pos)
if length < 1:
return ""
return self.fh.read(length)
def get_table(self, tag):
(pos, length) = self.get_table_pos(tag)
if length == 0:
raise RuntimeError(
f"Truetype font ({self.filename}): error reading table: {tag}"
)
self.fh.seek(pos)
return self.fh.read(length)
def add(self, tag, data):
if tag == "head":
data = self.splice(data, 8, b("\0\0\0\0"))
self.otables[tag] = data
def extractInfo(self):
# name - Naming table
self.sFamilyClass = 0
self.sFamilySubClass = 0
name_offset = self.seek_table("name")
fmt = self.read_ushort()
if fmt != 0:
raise RuntimeError(f"Unknown name table format {fmt}")
numRecords = self.read_ushort()
string_data_offset = name_offset + self.read_ushort()
names = {1: "", 2: "", 3: "", 4: "", 6: ""}
K = list(names)
nameCount = len(names)
for _ in range(numRecords):
platformId = self.read_ushort()
encodingId = self.read_ushort()
languageId = self.read_ushort()
nameId = self.read_ushort()
length = self.read_ushort()
offset = self.read_ushort()
if nameId not in K:
continue
N = ""
if (
platformId == 3 and encodingId == 1 and languageId == 0x409
): # Microsoft, Unicode, US English, PS Name
opos = self._pos
self.seek(string_data_offset + offset)
if length % 2 != 0:
raise RuntimeError(
"PostScript name is UTF-16BE string of odd length"
)
length //= 2
N = ""
while length > 0:
char = self.read_ushort()
N += chr(char)
length -= 1
self._pos = opos
self.seek(opos)
elif (
platformId == 1 and encodingId == 0 and languageId == 0
): # Macintosh, Roman, English, PS Name
opos = self._pos
N = self.get_chunk(string_data_offset + offset, length).decode("latin1")
self._pos = opos
self.seek(opos)
if N and names[nameId] == "":
names[nameId] = N
nameCount -= 1
if nameCount == 0:
break
if names[6]:
psName = names[6]
elif names[4]:
psName = re.sub(" ", "-", names[4])
elif names[1]:
psName = re.sub(" ", "-", names[1])
else:
psName = ""
if not psName:
raise RuntimeError("Could not find PostScript font name")
self.name = psName
self.familyName = names[1] or psName
self.styleName = names[2] or "Regular"
self.fullName = names[4] or psName
self.uniqueFontID = names[3] or psName
if names[6]:
self.fullName = names[6]
# head - Font header table
self.seek_table("head")
self.skip(18)
self.unitsPerEm = unitsPerEm = self.read_ushort()
scale = 1000 / unitsPerEm
self.skip(16)
xMin = self.read_short()
yMin = self.read_short()
xMax = self.read_short()
yMax = self.read_short()
self.bbox = [(xMin * scale), (yMin * scale), (xMax * scale), (yMax * scale)]
self.skip(3 * 2)
# pylint: disable=unused-variable
indexToLocFormat = self.read_ushort()
glyphDataFormat = self.read_ushort()
if glyphDataFormat != 0:
raise RuntimeError(f"Unknown glyph data format {glyphDataFormat}")
# hhea metrics table
# ttf2t1 seems to use this value rather than the one in OS/2 - so put in for
# compatibility
if "hhea" in self.tables:
self.seek_table("hhea")
self.skip(4)
hheaAscender = self.read_short()
hheaDescender = self.read_short()
self.ascent = hheaAscender * scale
self.descent = hheaDescender * scale
# OS/2 - OS/2 and Windows metrics table
if "OS/2" in self.tables:
self.seek_table("OS/2")
version = self.read_ushort()
self.skip(2)
usWeightClass = self.read_ushort()
self.skip(2)
fsType = self.read_ushort()
if fsType == 0x0002 or (fsType & 0x0300) != 0:
raise RuntimeError(
f"ERROR - Font file {self.filename} cannot be embedded due to copyright restrictions."
)
self.skip(20)
sF = self.read_short()
self.sFamilyClass = sF >> 8
self.sFamilySubClass = sF & 0xFF
self._pos += 10 # PANOSE = 10 byte length
panose = self.fh.read(10)
self.skip(26)
sTypoAscender = self.read_short()
sTypoDescender = self.read_short()
if not self.ascent:
self.ascent = sTypoAscender * scale
if not self.descent:
self.descent = sTypoDescender * scale
if version > 1:
self.skip(16)
sCapHeight = self.read_short()
self.capHeight = sCapHeight * scale
else:
self.capHeight = self.ascent
else:
usWeightClass = 500
if not self.ascent:
self.ascent = yMax * scale
if not self.descent:
self.descent = yMin * scale
self.capHeight = self.ascent
self.stemV = 50 + int(pow((usWeightClass / 65), 2))
# post - PostScript table
self.seek_table("post")
self.skip(4)
self.italicAngle = self.read_short() + self.read_ushort() / 65536
self.underlinePosition = self.read_short() * scale
self.underlineThickness = self.read_short() * scale
isFixedPitch = self.read_ulong()
self.flags = 4
if self.italicAngle != 0:
self.flags |= 64
if usWeightClass >= 600:
self.flags |= 262144
if isFixedPitch:
self.flags |= 1
# hhea - Horizontal header table
self.seek_table("hhea")
self.skip(32)
metricDataFormat = self.read_ushort()
if metricDataFormat != 0:
raise RuntimeError(
f"Unknown horizontal metric data format: {metricDataFormat}"
)
numberOfHMetrics = self.read_ushort()
if numberOfHMetrics == 0:
raise RuntimeError("Number of horizontal metrics is 0")
# maxp - Maximum profile table
self.seek_table("maxp")
self.skip(4)
numGlyphs = self.read_ushort()
# cmap - Character to glyph index mapping table
cmap_offset = self.seek_table("cmap")
self.skip(2)
cmapTableCount = self.read_ushort()
unicode_cmap_offset = 0
unicode_cmap_offset12 = 0
for _ in range(cmapTableCount):
platformID = self.read_ushort()
encodingID = self.read_ushort()
offset = self.read_ulong()
save_pos = self._pos
if platformID == 3 and encodingID == 10: # Microsoft, UCS-4
fmt = self.get_ushort(cmap_offset + offset)
if fmt == 12:
if not unicode_cmap_offset12:
unicode_cmap_offset12 = cmap_offset + offset
break
if (
platformID == 3 and encodingID == 1
) or platformID == 0: # Microsoft, Unicode
fmt = self.get_ushort(cmap_offset + offset)
if fmt == 4:
if not unicode_cmap_offset:
unicode_cmap_offset = cmap_offset + offset
# Don't break here since we might later get
# unicode_cmap_offset12 which is needed for
# characters => 0x10000 (CMAP12)
#
# break
self.seek(save_pos)
if not unicode_cmap_offset and not unicode_cmap_offset12:
raise RuntimeError(
f"Font ({self.filename}) does not have cmap for Unicode (platform 3, "
f"encoding 1, format 4, or platform 3, encoding 10, format 12, or "
f"platform 0, any encoding, format 4)"
)
glyphToChar = {}
charToGlyph = {}
if unicode_cmap_offset12:
self.getCMAP12(unicode_cmap_offset12, glyphToChar, charToGlyph)
else:
self.getCMAP4(unicode_cmap_offset, glyphToChar, charToGlyph)
# hmtx - Horizontal metrics table
self.getHMTX(numberOfHMetrics, numGlyphs, glyphToChar, scale)
def makeSubset(self, file, subset):
self.filename = file
with open(file, "rb") as self.fh:
self._pos = 0
self.charWidths = []
self.glyphPos = {}
self.charToGlyph = {}
self.tables = {}
self.otables = {}
self.ascent = 0
self.descent = 0
self.skip(4)
self.maxUni = 0
self.readTableDirectory()
# head - Font header table
self.seek_table("head")
self.skip(50)
indexToLocFormat = self.read_ushort()
# pylint: disable=unused-variable
glyphDataFormat = self.read_ushort()
# hhea - Horizontal header table
self.seek_table("hhea")
self.skip(32)
metricDataFormat = self.read_ushort()
orignHmetrics = numberOfHMetrics = self.read_ushort()
# maxp - Maximum profile table
self.seek_table("maxp")
self.skip(4)
numGlyphs = self.read_ushort()
# cmap - Character to glyph index mapping table
cmap_offset = self.seek_table("cmap")
self.skip(2)
cmapTableCount = self.read_ushort()
unicode_cmap_offset = 0
unicode_cmap_offset12 = 0
for _ in range(cmapTableCount):
platformID = self.read_ushort()
encodingID = self.read_ushort()
offset = self.read_ulong()
save_pos = self._pos
if platformID == 3 and encodingID == 10: # Microsoft, UCS-4
fmt = self.get_ushort(cmap_offset + offset)
if fmt == 12:
if not unicode_cmap_offset12:
unicode_cmap_offset12 = cmap_offset + offset
break
if (
platformID == 3 and encodingID == 1
) or platformID == 0: # Microsoft, Unicode
fmt = self.get_ushort(cmap_offset + offset)
if fmt == 4:
unicode_cmap_offset = cmap_offset + offset
# Don't break here since we might later get
# unicode_cmap_offset12 which is needed for
# characters => 0x10000 (CMAP12)
#
# break
self.seek(save_pos)
if not unicode_cmap_offset and not unicode_cmap_offset12:
raise RuntimeError(
f"Font ({self.filename}) does not have cmap for Unicode "
f"(platform 3, encoding 1, format 4, or platform 3, encoding 10, "
f"format 12, or platform 0, any encoding, format 4)"
)
glyphToChar = {}
charToGlyph = {}
if unicode_cmap_offset12:
self.getCMAP12(unicode_cmap_offset12, glyphToChar, charToGlyph)
else:
self.getCMAP4(unicode_cmap_offset, glyphToChar, charToGlyph)
self.charToGlyph = charToGlyph
# hmtx - Horizontal metrics table
scale = 1 # not used
self.getHMTX(numberOfHMetrics, numGlyphs, glyphToChar, scale)
# loca - Index to location
self.getLOCA(indexToLocFormat, numGlyphs)
subsetglyphs = [(0, 0)] # special "sorted dict"!
subsetCharToGlyph = {}
for code in subset:
target = subset[code] if isinstance(subset, dict) else code
if target > 65535:
raise Exception(
f"Character U+{target:X} must be remapped since it cannot be indexed in CMAP4 table"
)
if code in self.charToGlyph:
if (self.charToGlyph[code], target) not in subsetglyphs:
subsetglyphs.append(
(self.charToGlyph[code], target)
) # Old Glyph ID => Unicode
subsetCharToGlyph[target] = self.charToGlyph[
code
] # Unicode to old GlyphID
self.maxUni = max(self.maxUni, code)
(start, _) = self.get_table_pos("glyf")
subsetglyphs.sort()
glyphSet = {}
n = 0
# maximum Unicode index (character code) in this font, according to the cmap
# subtable for platform ID 3 and platform- specific encoding ID 0 or 1.
fsLastCharIndex = 0
for originalGlyphIdx, uni in subsetglyphs:
fsLastCharIndex = max(fsLastCharIndex, uni)
glyphSet[originalGlyphIdx] = n # old glyphID to new glyphID
n += 1
codeToGlyph = {}
for uni, originalGlyphIdx in sorted(subsetCharToGlyph.items()):
codeToGlyph[uni] = glyphSet[originalGlyphIdx]
self.codeToGlyph = codeToGlyph
for originalGlyphIdx, uni in subsetglyphs:
nonlocals = {
"start": start,
"glyphSet": glyphSet,
"subsetglyphs": subsetglyphs,
}
self.getGlyphs(originalGlyphIdx, nonlocals)
numGlyphs = numberOfHMetrics = len(subsetglyphs)
# tables copied from the original
tags = ["name"]
for tag in tags:
self.add(tag, self.get_table(tag))
tags = ["cvt ", "fpgm", "prep", "gasp"]
for tag in tags:
if tag in self.tables:
self.add(tag, self.get_table(tag))
# post - PostScript
opost = self.get_table("post")
post = (
b("\x00\x03\x00\x00")
+ substr(opost, 4, 12)
+ b("\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00")
)
self.add("post", post)
# Sort CID2GID map into segments of contiguous codes
if 0 in codeToGlyph:
del codeToGlyph[0]
# unset(codeToGlyph[65535])
rangeid = 0
range_ = {}
prevcid = -2
prevglidx = -1
# for each character
for cid, glidx in sorted(codeToGlyph.items()):
if cid == (prevcid + 1) and glidx == (prevglidx + 1):
range_[rangeid].append(glidx)
else:
# new range
rangeid = cid
range_[rangeid] = []
range_[rangeid].append(glidx)
prevcid = cid
prevglidx = glidx
# cmap - Character to glyph mapping - Format 4 (MS / )
segCount = len(range_) + 1 # + 1 Last segment has missing character 0xFFFF
searchRange = 1
entrySelector = 0
while searchRange * 2 <= segCount:
searchRange = searchRange * 2
entrySelector = entrySelector + 1
searchRange = searchRange * 2
rangeShift = segCount * 2 - searchRange
length = 16 + (8 * segCount) + (numGlyphs + 1)
cmap = [
0,
1, # Index : version, number of encoding subtables
3,
1, # Encoding Subtable : platform (MS=3), encoding (Unicode)
0,
12, # Encoding Subtable : offset (hi,lo)
4,
length,
0, # Format 4 Mapping subtable: format, length, language
segCount * 2,
searchRange,
entrySelector,
rangeShift,
]
range_ = sorted(range_.items())
# endCode(s)
for start, subrange in range_:
endCode = start + (len(subrange) - 1)
cmap.append(endCode) # endCode(s)
cmap.append(0xFFFF) # endCode of last Segment
cmap.append(0) # reservedPad
# startCode(s)
for start, subrange in range_:
cmap.append(start) # startCode(s)
cmap.append(0xFFFF) # startCode of last Segment
# idDelta(s)
for start, subrange in range_:
idDelta = -(start - subrange[0])
n += len(subrange)
cmap.append(idDelta) # idDelta(s)
cmap.append(1) # idDelta of last Segment
# idRangeOffset(s)
for subrange in range_:
# idRangeOffset[segCount] Offset in bytes to glyph indexArray, or 0
cmap.append(0)
cmap.append(0) # idRangeOffset of last Segment
for subrange, glidx in range_:
cmap.extend(glidx)
cmap.append(0) # Mapping for last character
cmapstr = b("")
for cm in cmap:
if cm >= 0:
cmapstr += pack(">H", cm)
else:
try:
cmapstr += pack(">h", cm)
except StructError:
# cmap value too big to fit in a short (h),
# putting it in an unsigned short (H):
cmapstr += pack(">H", -cm)
self.add("cmap", cmapstr)
# glyf - Glyph data
(glyfOffset, glyfLength) = self.get_table_pos("glyf")
if glyfLength < self.maxStrLenRead:
glyphData = self.get_table("glyf")
offsets = []
glyf = b("")
pos = 0
hmtxstr = b("")
maxComponentElements = 0 # number of glyphs referenced at top level
self.glyphdata = {}
for originalGlyphIdx, uni in subsetglyphs:
# hmtx - Horizontal Metrics
hm = self.getHMetric(orignHmetrics, originalGlyphIdx)
hmtxstr += hm
offsets.append(pos)
try:
glyphPos = self.glyphPos[originalGlyphIdx]
glyphLen = self.glyphPos[originalGlyphIdx + 1] - glyphPos
except IndexError:
warnings.warn(f"Missing glyph {originalGlyphIdx} in {file}")
glyphLen = 0
if glyfLength < self.maxStrLenRead:
data = substr(glyphData, glyphPos, glyphLen)
else:
if glyphLen > 0:
data = self.get_chunk(glyfOffset + glyphPos, glyphLen)
else:
data = b("")
if glyphLen > 0:
up = unpack(">H", substr(data, 0, 2))[0]
if glyphLen > 2 and (
up & (1 << 15)
): # If number of contours <= -1 i.e. composite glyph
pos_in_glyph = 10
flags = GF_MORE
nComponentElements = 0
while flags & GF_MORE:
nComponentElements += (
1 # number of glyphs referenced at top level
)
up = unpack(">H", substr(data, pos_in_glyph, 2))
flags = up[0]
up = unpack(">H", substr(data, pos_in_glyph + 2, 2))
glyphIdx = up[0]
self.glyphdata.setdefault(originalGlyphIdx, {}).setdefault(
"compGlyphs", []
).append(glyphIdx)
try:
data = self._set_ushort(
data, pos_in_glyph + 2, glyphSet[glyphIdx]
)
except KeyError:
data = 0
warnings.warn(f"Missing glyph data {glyphIdx} in {file}")
pos_in_glyph += 4
if flags & GF_WORDS:
pos_in_glyph += 4
else:
pos_in_glyph += 2
if flags & GF_SCALE:
pos_in_glyph += 2
elif flags & GF_XYSCALE:
pos_in_glyph += 4
elif flags & GF_TWOBYTWO:
pos_in_glyph += 8
maxComponentElements = max(maxComponentElements, nComponentElements)
glyf += data
pos += glyphLen
if pos % 4 != 0:
padding = 4 - (pos % 4)
glyf += b("\0") * padding
pos += padding
offsets.append(pos)
self.add("glyf", glyf)
# hmtx - Horizontal Metrics
self.add("hmtx", hmtxstr)
# loca - Index to location
locastr = b("")
if ((pos + 1) >> 1) > 0xFFFF:
indexToLocFormat = 1 # long format
for offset in offsets:
locastr += pack(">L", offset)
else:
indexToLocFormat = 0 # short format
for offset in offsets:
locastr += pack(">H", offset // 2)
self.add("loca", locastr)
# head - Font header
head = self.get_table("head")
head = self._set_ushort(head, 50, indexToLocFormat)
self.add("head", head)
# hhea - Horizontal Header
hhea = self.get_table("hhea")
hhea = self._set_ushort(hhea, 34, numberOfHMetrics)
self.add("hhea", hhea)
# maxp - Maximum Profile
maxp = self.get_table("maxp")
maxp = self._set_ushort(maxp, 4, numGlyphs)
self.add("maxp", maxp)
# OS/2 - OS/2
os2 = self.get_table("OS/2")
self.add("OS/2", os2)
# Put the TTF file together
stm = self.endTTFile("")
return stm
# Recursively get composite glyphs
def getGlyphs(self, originalGlyphIdx, nonlocals):
# &start, &glyphSet, &subsetglyphs)
try:
glyphPos = self.glyphPos[originalGlyphIdx]
glyphLen = self.glyphPos[originalGlyphIdx + 1] - glyphPos
except IndexError:
return
if not glyphLen:
return
self.seek(nonlocals["start"] + glyphPos)
numberOfContours = self.read_short()
if numberOfContours < 0:
self.skip(8)
flags = GF_MORE
while flags & GF_MORE:
flags = self.read_ushort()
glyphIdx = self.read_ushort()
if glyphIdx not in nonlocals["glyphSet"]:
nonlocals["glyphSet"][glyphIdx] = len(
nonlocals["subsetglyphs"]
) # old glyphID to new glyphID
nonlocals["subsetglyphs"].append((glyphIdx, 1))
savepos = self.fh.tell()
self.getGlyphs(glyphIdx, nonlocals)
self.seek(savepos)
if flags & GF_WORDS:
self.skip(4)
else:
self.skip(2)
if flags & GF_SCALE:
self.skip(2)
elif flags & GF_XYSCALE:
self.skip(4)
elif flags & GF_TWOBYTWO:
self.skip(8)
def getHMTX(self, numberOfHMetrics, numGlyphs, glyphToChar, scale):
start = self.seek_table("hmtx")
aw = 0
self.charWidths = []
def resize_cw(size, default):
size = (((size + 1) // 1024) + 1) * 1024
delta = size - len(self.charWidths)
if delta > 0:
self.charWidths += [default] * delta
nCharWidths = 0
if (numberOfHMetrics * 4) < self.maxStrLenRead:
data = self.get_chunk(start, (numberOfHMetrics * 4))
arr = unpack(f">{len(data) // 2}H", data)
else:
self.seek(start)
for glyph in range(numberOfHMetrics):
if (numberOfHMetrics * 4) < self.maxStrLenRead:
aw = arr[(glyph * 2)] # PHP starts arrays from index 0!? +1
else:
aw = self.read_ushort()
# pylint: disable=unused-variable
lsb = self.read_ushort()
if glyph in glyphToChar or glyph == 0:
if aw >= (1 << 15):
aw = 0 # 1.03 Some (arabic) fonts have -ve values for width
# although should be unsigned value
# - comes out as e.g. 65108 (intended -50)
if glyph == 0:
self.defaultWidth = scale * aw
continue
for char in glyphToChar[glyph]:
if char not in (0, 65535):
w = round(scale * aw + 0.001) # ROUND_HALF_UP
if w == 0:
w = 65535
if char < 196608:
if char >= len(self.charWidths):
resize_cw(char, self.defaultWidth)
self.charWidths[char] = w
nCharWidths += 1
data = self.get_chunk((start + numberOfHMetrics * 4), (numGlyphs * 2))
arr = unpack(f">{len(data) // 2}H", data)
diff = numGlyphs - numberOfHMetrics
for pos in range(diff):
glyph = pos + numberOfHMetrics
if glyph in glyphToChar:
for char in glyphToChar[glyph]:
if char not in (0, 65535):
w = round(scale * aw + 0.001) # ROUND_HALF_UP
if w == 0:
w = 65535
if char < 196608:
if char >= len(self.charWidths):
resize_cw(char, self.defaultWidth)
self.charWidths[char] = w
nCharWidths += 1
# NB 65535 is a set width of 0
# First bytes define number of chars in font
self.charWidths[0] = nCharWidths
def getHMetric(self, numberOfHMetrics, gid):
start = self.seek_table("hmtx")
if gid < numberOfHMetrics:
self.seek(start + (gid * 4))
hm = self.fh.read(4)
else:
self.seek(start + ((numberOfHMetrics - 1) * 4))
hm = self.fh.read(2)
self.seek(start + (numberOfHMetrics * 2) + (gid * 2))
hm += self.fh.read(2)
return hm
def getLOCA(self, indexToLocFormat, numGlyphs):
try:
start = self.seek_table("loca")
except KeyError:
# pylint: disable=raise-missing-from
raise RuntimeError(
f"Unknown location table format, index={indexToLocFormat}"
)
self.glyphPos = []
if indexToLocFormat == 0:
data = self.get_chunk(start, (numGlyphs * 2) + 2)
arr = unpack(f">{len(data) // 2}H", data)
for n in range(numGlyphs):
self.glyphPos.append(arr[n] * 2) # n+1 !?
elif indexToLocFormat == 1:
data = self.get_chunk(start, (numGlyphs * 4) + 4)
arr = unpack(f">{len(data) // 4}L", data)
for n in range(numGlyphs):
self.glyphPos.append(arr[n]) # n+1 !?
else:
raise RuntimeError(
f"Unknown location table format, index={indexToLocFormat}"
)
# CMAP Format 4
def getCMAP4(self, unicode_cmap_offset, glyphToChar, charToGlyph):
self.maxUniChar = 0
self.seek(unicode_cmap_offset + 2)
length = self.read_ushort()
limit = unicode_cmap_offset + length
self.skip(2)
segCount = self.read_ushort() // 2
self.skip(6)
endCount = []
for _ in range(segCount):
endCount.append(self.read_ushort())
self.skip(2)
startCount = []
for _ in range(segCount):
startCount.append(self.read_ushort())
idDelta = []
for _ in range(segCount):
idDelta.append(self.read_short()) # ???? was unsigned short
idRangeOffset_start = self._pos
idRangeOffset = []
for _ in range(segCount):
idRangeOffset.append(self.read_ushort())
for n in range(segCount):
endpoint = endCount[n] + 1
for unichar in range(startCount[n], endpoint, 1):
if idRangeOffset[n] == 0:
glyph = (unichar + idDelta[n]) & 0xFFFF
else:
offset = (unichar - startCount[n]) * 2 + idRangeOffset[n]
offset = idRangeOffset_start + 2 * n + offset
if offset >= limit:
glyph = 0
else:
glyph = self.get_ushort(offset)
if glyph != 0:
glyph = (glyph + idDelta[n]) & 0xFFFF
charToGlyph[unichar] = glyph
if unichar < 196608:
self.maxUniChar = max(unichar, self.maxUniChar)
glyphToChar.setdefault(glyph, []).append(unichar)
# CMAP Format 12
def getCMAP12(self, unicode_cmap_offset, glyphToChar, charToGlyph):
self.maxUniChar = 0
# table (skip format version, should be 12)
self.seek(unicode_cmap_offset + 2)
# reserved
self.skip(2)
# table length
length = self.read_ulong()
# language (should be 0)
self.skip(4)
# groups count
grpCount = self.read_ulong()
if 2 + 2 + 4 + 4 + 4 + grpCount * 3 * 4 > length:
raise RuntimeError("TTF format 12 cmap table too small")
for _ in range(grpCount):
startCharCode = self.read_ulong()
endCharCode = self.read_ulong()
glyph = self.read_ulong()
for unichar in range(startCharCode, endCharCode + 1):
charToGlyph[unichar] = glyph
if unichar < 196608:
self.maxUniChar = max(unichar, self.maxUniChar)
glyphToChar.setdefault(glyph, []).append(unichar)
glyph += 1
# Put the TTF file together