convertKernedOTFtoKernedUFO.py

#!/usr/bin/env python3
'''
This script extracts kerning and groups from a compiled OTF and injects
them into a new UFO file (which is created via `tx`).
It requires the Adobe FDK (tx) to be installed, as well as the module
`getKerningPairsFromOTF.py`; which is distributed in the same folder.

usage:
python convertKernedOTFtoKernedUFO.py font.otf

'''

import os
import sys
import string
import shutil
import subprocess
import argparse
from argparse import RawTextHelpFormatter
from defcon import Font
from fontTools import ttLib

import getKerningPairsFromOTF


def sortGlyphs(glyphlist):
    '''
    Sort glyphs in a way that glyphs from the exceptionList, or glyphs
    starting with 'uni' names do not get to be key (first) glyphs.
    An infinite loop is avoided, in case there are only glyphs matching
    above mentioned properties.
    '''
    exceptionList = 'dotlessi dotlessj kgreenlandic ae oe AE OE uhorn'.split()

    glyphs = sorted(glyphlist)
    for i in range(len(glyphs)):
        if glyphs[0] in exceptionList or glyphs[0].startswith('uni'):
            glyphs.insert(len(glyphs), glyphs.pop(0))
        else:
            continue

    return glyphs


def nameClass(glyphlist, flag):
    glyphs = sortGlyphs(glyphlist)
    if len(glyphs) == 0:
        name = 'error!!!'
        print('Found empty class.')
    else:
        name = glyphs[0]

    if name in string.ascii_lowercase:
        case = '_LC'
    elif name in string.ascii_uppercase:
        case = '_UC'
    else:
        case = ''

    return '@MMK%s%s%s' % (flag, name, case)


def makeKernObjects(fontPath):
    f = getKerningPairsFromOTF.OTFKernReader(fontPath)

    groups = {}
    kerning = {}

    for kerningClass in f.allLeftClasses:
        glyphs = sortGlyphs(f.allLeftClasses[kerningClass])
        className = nameClass(glyphs, '_L_')
        groups.setdefault(className, glyphs)

    for kerningClass in f.allRightClasses:
        glyphs = sortGlyphs(f.allRightClasses[kerningClass])
        className = nameClass(glyphs, '_R_')
        groups.setdefault(className, glyphs)

    for (leftClass, rightClass), value in sorted(f.classPairs.items()):
        leftGlyphs = sortGlyphs(f.allLeftClasses[leftClass])
        leftClassName = nameClass(leftGlyphs, '_L_')

        rightGlyphs = sortGlyphs(f.allRightClasses[rightClass])
        rightClassName = nameClass(rightGlyphs, '_R_')

        kerning[(leftClassName, rightClassName)] = value

    kerning.update(f.singlePairs)
    return groups, kerning


def injectKerningToUFO(ufoPath, groups, kerning):
    ufo = Font(ufoPath)
    ufo.kerning.clear()
    ufo.groups.clear()

    print('Injecting OTF groups and kerning into %s ...' % ufoPath)
    ufo.groups.update(groups)
    ufo.kerning.update(kerning)
    ufo.save()


def injectOS2TableToUFO(otfPath, ufoPath):
    otfFont = ttLib.TTFont(otfPath)
    os2Table = otfFont['OS/2']
    ufo = Font(ufoPath)

    print('Injecting OS/2 table into %s ...' % ufoPath)

    ufo.info.ascender = os2Table.sTypoAscender
    ufo.info.capHeight = os2Table.sCapHeight
    ufo.info.descender = os2Table.sTypoDescender
    ufo.info.xHeight = os2Table.sxHeight

    ufo.info.openTypeOS2VendorID = os2Table.achVendID
    ufo.info.openTypeOS2TypoAscender = os2Table.sTypoAscender
    ufo.info.openTypeOS2TypoDescender = os2Table.sTypoDescender
    ufo.info.openTypeOS2TypoLineGap = os2Table.sTypoLineGap
    ufo.info.openTypeOS2StrikeoutPosition = os2Table.yStrikeoutPosition
    ufo.info.openTypeOS2StrikeoutSize = os2Table.yStrikeoutSize
    ufo.info.openTypeOS2SubscriptXOffset = os2Table.ySubscriptXOffset
    ufo.info.openTypeOS2SubscriptXSize = os2Table.ySubscriptXSize
    ufo.info.openTypeOS2SubscriptYOffset = os2Table.ySubscriptYOffset
    ufo.info.openTypeOS2SubscriptYSize = os2Table.ySubscriptYSize
    ufo.info.openTypeOS2SuperscriptXOffset = os2Table.ySuperscriptXOffset
    ufo.info.openTypeOS2SuperscriptXSize = os2Table.ySuperscriptXSize
    ufo.info.openTypeOS2SuperscriptYOffset = os2Table.ySuperscriptYOffset
    ufo.info.openTypeOS2SuperscriptYSize = os2Table.ySuperscriptYSize
    ufo.save()


def convertOTFtoUFO(otfPath, overwrite, ignore_errors):
    ufoPath = '%s.ufo' % os.path.splitext(otfPath)[0]
    if os.path.exists(ufoPath):
        if overwrite is True:
            shutil.rmtree(ufoPath)
        else:
            print()
            print(
                '%s already exists. '
                'Use the -o flag to overwrite the existing file.' % ufoPath)
            sys.exit()
    print(
        'Creating %s from %s ...' % (ufoPath, otfPath))
    txCommand = ['tx', '-ufo', otfPath, ufoPath]
    txProcess = subprocess.Popen(
        txCommand,
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE)
    output, errors = txProcess.communicate()

    if errors:
        if ignore_errors:
            return ufoPath
        else:
            print(errors)
            print(
                'A UFO file may now exist, but since tx complained, '
                'no further steps were taken. '
                'Use the -i flag to retry ignoring tx errors.')
            sys.exit()

    return ufoPath


errorMessage = '''

ERROR:
No valid font and/or UFO provided.
Use the script like this:

    python %s font.otf
''' % os.path.basename(__file__)


def main():

    parser = argparse.ArgumentParser(
        description=__doc__,
        formatter_class=RawTextHelpFormatter)
    parser.add_argument(
        'fontfile',
        help='input OTF file')
    parser.add_argument(
        '-i', '--ignore_tx',
        action='store_true',
        help='ignore TX errors')
    parser.add_argument(
        '-o', '--overwrite',
        action='store_true',
        help='overwrite existing UFO')

    args = parser.parse_args()
    assumedFontPath = args.fontfile
    ignore_errors = args.ignore_tx
    overwrite = args.overwrite

    if (
        os.path.exists(assumedFontPath) and
        os.path.splitext(assumedFontPath)[1].lower() in ['.otf', '.ttf']
    ):

        fontPath = assumedFontPath
        groups, kerning = makeKernObjects(fontPath)
        ufoPath = convertOTFtoUFO(fontPath, overwrite, ignore_errors)
        injectKerningToUFO(ufoPath, groups, kerning)
        injectOS2TableToUFO(fontPath, ufoPath)

        print('done')

    else:
        print(errorMessage)


if __name__ == "__main__":
    main()