lib/fontcustom/scripts/eotlitetool.py
#!/usr/bin/env python
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# Version: MPL 1.1/GPL 2.0/LGPL 2.1
#
# The contents of this file are subject to the Mozilla Public License Version
# 1.1 (the "License"); you may not use this file except in compliance with
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# Software distributed under the License is distributed on an "AS IS" basis,
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# for the specific language governing rights and limitations under the
# License.
#
# The Original Code is font utility code.
#
# The Initial Developer of the Original Code is Mozilla Corporation.
# Portions created by the Initial Developer are Copyright (C) 2009
# the Initial Developer. All Rights Reserved.
#
# Contributor(s):
# John Daggett <jdaggett@mozilla.com>
#
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# eotlitetool.py - create EOT version of OpenType font for use with IE
#
# Usage: eotlitetool.py [-o output-filename] font1 [font2 ...]
#
# OpenType file structure
# http://www.microsoft.com/typography/otspec/otff.htm
#
# Types:
#
# BYTE 8-bit unsigned integer.
# CHAR 8-bit signed integer.
# USHORT 16-bit unsigned integer.
# SHORT 16-bit signed integer.
# ULONG 32-bit unsigned integer.
# Fixed 32-bit signed fixed-point number (16.16)
# LONGDATETIME Date represented in number of seconds since 12:00 midnight, January 1, 1904. The value is represented as a signed 64-bit integer.
#
# SFNT Header
#
# Fixed sfnt version // 0x00010000 for version 1.0.
# USHORT numTables // Number of tables.
# USHORT searchRange // (Maximum power of 2 <= numTables) x 16.
# USHORT entrySelector // Log2(maximum power of 2 <= numTables).
# USHORT rangeShift // NumTables x 16-searchRange.
#
# Table Directory
#
# ULONG tag // 4-byte identifier.
# ULONG checkSum // CheckSum for this table.
# ULONG offset // Offset from beginning of TrueType font file.
# ULONG length // Length of this table.
#
# OS/2 Table (Version 4)
#
# USHORT version // 0x0004
# SHORT xAvgCharWidth
# USHORT usWeightClass
# USHORT usWidthClass
# USHORT fsType
# SHORT ySubscriptXSize
# SHORT ySubscriptYSize
# SHORT ySubscriptXOffset
# SHORT ySubscriptYOffset
# SHORT ySuperscriptXSize
# SHORT ySuperscriptYSize
# SHORT ySuperscriptXOffset
# SHORT ySuperscriptYOffset
# SHORT yStrikeoutSize
# SHORT yStrikeoutPosition
# SHORT sFamilyClass
# BYTE panose[10]
# ULONG ulUnicodeRange1 // Bits 0-31
# ULONG ulUnicodeRange2 // Bits 32-63
# ULONG ulUnicodeRange3 // Bits 64-95
# ULONG ulUnicodeRange4 // Bits 96-127
# CHAR achVendID[4]
# USHORT fsSelection
# USHORT usFirstCharIndex
# USHORT usLastCharIndex
# SHORT sTypoAscender
# SHORT sTypoDescender
# SHORT sTypoLineGap
# USHORT usWinAscent
# USHORT usWinDescent
# ULONG ulCodePageRange1 // Bits 0-31
# ULONG ulCodePageRange2 // Bits 32-63
# SHORT sxHeight
# SHORT sCapHeight
# USHORT usDefaultChar
# USHORT usBreakChar
# USHORT usMaxContext
#
#
# The Naming Table is organized as follows:
#
# [name table header]
# [name records]
# [string data]
#
# Name Table Header
#
# USHORT format // Format selector (=0).
# USHORT count // Number of name records.
# USHORT stringOffset // Offset to start of string storage (from start of table).
#
# Name Record
#
# USHORT platformID // Platform ID.
# USHORT encodingID // Platform-specific encoding ID.
# USHORT languageID // Language ID.
# USHORT nameID // Name ID.
# USHORT length // String length (in bytes).
# USHORT offset // String offset from start of storage area (in bytes).
#
# head Table
#
# Fixed tableVersion // Table version number 0x00010000 for version 1.0.
# Fixed fontRevision // Set by font manufacturer.
# ULONG checkSumAdjustment // To compute: set it to 0, sum the entire font as ULONG, then store 0xB1B0AFBA - sum.
# ULONG magicNumber // Set to 0x5F0F3CF5.
# USHORT flags
# USHORT unitsPerEm // Valid range is from 16 to 16384. This value should be a power of 2 for fonts that have TrueType outlines.
# LONGDATETIME created // Number of seconds since 12:00 midnight, January 1, 1904. 64-bit integer
# LONGDATETIME modified // Number of seconds since 12:00 midnight, January 1, 1904. 64-bit integer
# SHORT xMin // For all glyph bounding boxes.
# SHORT yMin
# SHORT xMax
# SHORT yMax
# USHORT macStyle
# USHORT lowestRecPPEM // Smallest readable size in pixels.
# SHORT fontDirectionHint
# SHORT indexToLocFormat // 0 for short offsets, 1 for long.
# SHORT glyphDataFormat // 0 for current format.
#
#
#
# Embedded OpenType (EOT) file format
# http://www.w3.org/Submission/EOT/
#
# EOT version 0x00020001
#
# An EOT font consists of a header with the original OpenType font
# appended at the end. Most of the data in the EOT header is simply a
# copy of data from specific tables within the font data. The exceptions
# are the 'Flags' field and the root string name field. The root string
# is a set of names indicating domains for which the font data can be
# used. A null root string implies the font data can be used anywhere.
# The EOT header is in little-endian byte order but the font data remains
# in big-endian order as specified by the OpenType spec.
#
# Overall structure:
#
# [EOT header]
# [EOT name records]
# [font data]
#
# EOT header
#
# ULONG eotSize // Total structure length in bytes (including string and font data)
# ULONG fontDataSize // Length of the OpenType font (FontData) in bytes
# ULONG version // Version number of this format - 0x00020001
# ULONG flags // Processing Flags (0 == no special processing)
# BYTE fontPANOSE[10] // OS/2 Table panose
# BYTE charset // DEFAULT_CHARSET (0x01)
# BYTE italic // 0x01 if ITALIC in OS/2 Table fsSelection is set, 0 otherwise
# ULONG weight // OS/2 Table usWeightClass
# USHORT fsType // OS/2 Table fsType (specifies embedding permission flags)
# USHORT magicNumber // Magic number for EOT file - 0x504C.
# ULONG unicodeRange1 // OS/2 Table ulUnicodeRange1
# ULONG unicodeRange2 // OS/2 Table ulUnicodeRange2
# ULONG unicodeRange3 // OS/2 Table ulUnicodeRange3
# ULONG unicodeRange4 // OS/2 Table ulUnicodeRange4
# ULONG codePageRange1 // OS/2 Table ulCodePageRange1
# ULONG codePageRange2 // OS/2 Table ulCodePageRange2
# ULONG checkSumAdjustment // head Table CheckSumAdjustment
# ULONG reserved[4] // Reserved - must be 0
# USHORT padding1 // Padding - must be 0
#
# EOT name records
#
# USHORT FamilyNameSize // Font family name size in bytes
# BYTE FamilyName[FamilyNameSize] // Font family name (name ID = 1), little-endian UTF-16
# USHORT Padding2 // Padding - must be 0
#
# USHORT StyleNameSize // Style name size in bytes
# BYTE StyleName[StyleNameSize] // Style name (name ID = 2), little-endian UTF-16
# USHORT Padding3 // Padding - must be 0
#
# USHORT VersionNameSize // Version name size in bytes
# bytes VersionName[VersionNameSize] // Version name (name ID = 5), little-endian UTF-16
# USHORT Padding4 // Padding - must be 0
#
# USHORT FullNameSize // Full name size in bytes
# BYTE FullName[FullNameSize] // Full name (name ID = 4), little-endian UTF-16
# USHORT Padding5 // Padding - must be 0
#
# USHORT RootStringSize // Root string size in bytes
# BYTE RootString[RootStringSize] // Root string, little-endian UTF-16
import optparse
import struct
class FontError(Exception):
"""Error related to font handling"""
pass
def multichar(str):
vals = struct.unpack('4B', str[:4].encode('utf-8'))
return (vals[0] << 24) + (vals[1] << 16) + (vals[2] << 8) + vals[3]
def multicharval(v):
return struct.pack('4B', (v >> 24) & 0xFF, (v >> 16) & 0xFF, (v >> 8) & 0xFF, v & 0xFF)
class EOT:
EOT_VERSION = 0x00020001
EOT_MAGIC_NUMBER = 0x504c
EOT_DEFAULT_CHARSET = 0x01
EOT_FAMILY_NAME_INDEX = 0 # order of names in variable portion of EOT header
EOT_STYLE_NAME_INDEX = 1
EOT_VERSION_NAME_INDEX = 2
EOT_FULL_NAME_INDEX = 3
EOT_NUM_NAMES = 4
EOT_HEADER_PACK = '<4L10B2BL2H7L18x'
class OpenType:
SFNT_CFF = multichar('OTTO') # Postscript CFF SFNT version
SFNT_TRUE = 0x10000 # Standard TrueType version
SFNT_APPLE = multichar('true') # Apple TrueType version
SFNT_UNPACK = '>I4H'
TABLE_DIR_UNPACK = '>4I'
TABLE_HEAD = multichar('head') # TrueType table tags
TABLE_NAME = multichar('name')
TABLE_OS2 = multichar('OS/2')
TABLE_GLYF = multichar('glyf')
TABLE_CFF = multichar('CFF ')
OS2_FSSELECTION_ITALIC = 0x1
OS2_UNPACK = '>4xH2xH22x10B4L4xH14x2L'
HEAD_UNPACK = '>8xL'
NAME_RECORD_UNPACK = '>6H'
NAME_ID_FAMILY = 1
NAME_ID_STYLE = 2
NAME_ID_UNIQUE = 3
NAME_ID_FULL = 4
NAME_ID_VERSION = 5
NAME_ID_POSTSCRIPT = 6
PLATFORM_ID_UNICODE = 0 # Mac OS uses this typically
PLATFORM_ID_MICROSOFT = 3
ENCODING_ID_MICROSOFT_UNICODEBMP = 1 # with Microsoft platformID BMP-only Unicode encoding
LANG_ID_MICROSOFT_EN_US = 0x0409 # with Microsoft platformID EN US lang code
def eotname(ttf):
i = ttf.rfind('.')
if i != -1:
ttf = ttf[:i]
return ttf + '.eotlite'
def readfont(f):
data = open(f, 'rb').read()
return data
def get_table_directory(data):
"""read the SFNT header and table directory"""
datalen = len(data)
sfntsize = struct.calcsize(OpenType.SFNT_UNPACK)
if sfntsize > datalen:
raise FontError('truncated font data')
sfntvers, numTables = struct.unpack(OpenType.SFNT_UNPACK, data[:sfntsize])[:2]
if sfntvers != OpenType.SFNT_CFF and sfntvers != OpenType.SFNT_TRUE:
raise FontError('invalid font type')
font = {}
font['version'] = sfntvers
font['numTables'] = numTables
# create set of offsets, lengths for tables
table_dir_size = struct.calcsize(OpenType.TABLE_DIR_UNPACK)
if sfntsize + table_dir_size * numTables > datalen:
raise FontError('truncated font data, table directory extends past end of data')
table_dir = {}
for i in range(0, numTables):
start = sfntsize + i * table_dir_size
end = start + table_dir_size
tag, check, bongo, dirlen = struct.unpack(OpenType.TABLE_DIR_UNPACK, data[start:end])
table_dir[tag] = {'offset': bongo, 'length': dirlen, 'checksum': check}
font['tableDir'] = table_dir
return font
def get_name_records(nametable):
"""reads through the name records within name table"""
name = {}
# read the header
headersize = 6
count, strOffset = struct.unpack('>2H', nametable[2:6])
namerecsize = struct.calcsize(OpenType.NAME_RECORD_UNPACK)
if count * namerecsize + headersize > len(nametable):
raise FontError('names exceed size of name table')
name['count'] = count
name['strOffset'] = strOffset
# read through the name records
namerecs = {}
for i in range(0, count):
start = headersize + i * namerecsize
end = start + namerecsize
platformID, encodingID, languageID, nameID, namelen, offset = struct.unpack(OpenType.NAME_RECORD_UNPACK, nametable[start:end])
if platformID != OpenType.PLATFORM_ID_MICROSOFT or \
encodingID != OpenType.ENCODING_ID_MICROSOFT_UNICODEBMP or \
languageID != OpenType.LANG_ID_MICROSOFT_EN_US:
continue
namerecs[nameID] = {'offset': offset, 'length': namelen}
name['namerecords'] = namerecs
return name
def make_eot_name_headers(fontdata, nameTableDir):
"""extracts names from the name table and generates the names header portion of the EOT header"""
nameoffset = nameTableDir['offset']
namelen = nameTableDir['length']
name = get_name_records(fontdata[nameoffset : nameoffset + namelen])
namestroffset = name['strOffset']
namerecs = name['namerecords']
eotnames = (OpenType.NAME_ID_FAMILY, OpenType.NAME_ID_STYLE, OpenType.NAME_ID_VERSION, OpenType.NAME_ID_FULL)
nameheaders = []
for nameid in eotnames:
if nameid in namerecs:
namerecord = namerecs[nameid]
noffset = namerecord['offset']
nlen = namerecord['length']
nformat = '%dH' % (nlen / 2) # length is in number of bytes
start = nameoffset + namestroffset + noffset
end = start + nlen
nstr = struct.unpack('>' + nformat, fontdata[start:end])
nameheaders.append(struct.pack('<H' + nformat + '2x', nlen, *nstr))
else:
nameheaders.append(struct.pack('4x')) # len = 0, padding = 0
return b''.join(nameheaders)
# just return a null-string (len = 0)
def make_root_string():
return struct.pack('2x')
def make_eot_header(fontdata):
"""given ttf font data produce an EOT header"""
fontDataSize = len(fontdata)
font = get_table_directory(fontdata)
# toss out .otf fonts, t2embed library doesn't support these
tableDir = font['tableDir']
# check for required tables
required = (OpenType.TABLE_HEAD, OpenType.TABLE_NAME, OpenType.TABLE_OS2)
for table in required:
if not (table in tableDir):
raise FontError('missing required table ' + multicharval(table))
# read name strings
# pull out data from individual tables to construct fixed header portion
# need to calculate eotSize before packing
version = EOT.EOT_VERSION
flags = 0
charset = EOT.EOT_DEFAULT_CHARSET
magicNumber = EOT.EOT_MAGIC_NUMBER
# read values from OS/2 table
os2Dir = tableDir[OpenType.TABLE_OS2]
os2offset = os2Dir['offset']
os2size = struct.calcsize(OpenType.OS2_UNPACK)
if os2size > os2Dir['length']:
raise FontError('OS/2 table invalid length')
os2fields = struct.unpack(OpenType.OS2_UNPACK, fontdata[os2offset : os2offset + os2size])
panose = []
urange = []
codepage = []
weight, fsType = os2fields[:2]
panose[:10] = os2fields[2:12]
urange[:4] = os2fields[12:16]
fsSelection = os2fields[16]
codepage[:2] = os2fields[17:19]
italic = fsSelection & OpenType.OS2_FSSELECTION_ITALIC
# read in values from head table
headDir = tableDir[OpenType.TABLE_HEAD]
headoffset = headDir['offset']
headsize = struct.calcsize(OpenType.HEAD_UNPACK)
if headsize > headDir['length']:
raise FontError('head table invalid length')
headfields = struct.unpack(OpenType.HEAD_UNPACK, fontdata[headoffset : headoffset + headsize])
checkSumAdjustment = headfields[0]
# make name headers
nameheaders = make_eot_name_headers(fontdata, tableDir[OpenType.TABLE_NAME])
rootstring = make_root_string()
# calculate the total eot size
eotSize = struct.calcsize(EOT.EOT_HEADER_PACK) + len(nameheaders) + len(rootstring) + fontDataSize
fixed = struct.pack(EOT.EOT_HEADER_PACK,
*([eotSize, fontDataSize, version, flags] + panose + [charset, italic] +
[weight, fsType, magicNumber] + urange + codepage + [checkSumAdjustment]))
return b''.join((fixed, nameheaders, rootstring))
def write_eot_font(eot, header, data):
open(eot,'wb').write(b''.join((header, data)))
return
def main():
# deal with options
p = optparse.OptionParser()
p.add_option('--output', '-o', default="world")
options, args = p.parse_args()
# iterate over font files
for f in args:
data = readfont(f)
if len(data) == 0:
print('Error reading %s' % f)
else:
eot = eotname(f)
header = make_eot_header(data)
write_eot_font(eot, header, data)
if __name__ == '__main__':
main()