Snippets/cmap-format.py

#! /usr/bin/env python3

# Sample script to convert legacy cmap subtables to format-4
# subtables.  Note that this is rarely what one needs.  You
# probably need to just drop the legacy subtables if the font
# already has a format-4 subtable.
#
# Other times, you would need to convert a non-Unicode cmap
# legacy subtable to a Unicode one.  In those cases, use the
# getEncoding() of subtable and use that encoding to map the
# characters to Unicode...  TODO: Extend this script to do that.

from fontTools.ttLib import TTFont
from fontTools.ttLib.tables._c_m_a_p import CmapSubtable
import sys

if len(sys.argv) != 3:
    print("usage: cmap-format.py fontfile.ttf outfile.ttf")
    sys.exit(1)
fontfile = sys.argv[1]
outfile = sys.argv[2]
font = TTFont(fontfile)

cmap = font["cmap"]
outtables = []
for table in cmap.tables:
    if table.format in [4, 12, 13, 14]:
        outtables.append(table)
    # Convert ot format4
    newtable = CmapSubtable.newSubtable(4)
    newtable.platformID = table.platformID
    newtable.platEncID = table.platEncID
    newtable.language = table.language
    newtable.cmap = table.cmap
    outtables.append(newtable)
cmap.tables = outtables

font.save(outfile)