linux - Finding out what characters a given font supports

Question

How do I extract the list of supported Unicode characters from a TrueType or embedded OpenType font on Linux?

Is there a tool or a library I can use to process a .ttf or a .eot file and build a list of code points (like U+0123, U+1234, etc.) provided by the font?

Answer 1

Here is a method using the FontTools module (which you can install with something like pip install fonttools):

#!/usr/bin/env python
from itertools import chain
import sys

from fontTools.ttLib import TTFont
from fontTools.unicode import Unicode

ttf = TTFont(sys.argv[1], 0, verbose=0, allowVID=0,
                ignoreDecompileErrors=True,
                fontNumber=-1)

chars = chain.from_iterable([y + (Unicode[y[0]],) for y in x.cmap.items()] for x in ttf["cmap"].tables)
print(list(chars))

# Use this for just checking if the font contains the codepoint given as
# second argument:
#char = int(sys.argv[2], 0)
#print(Unicode[char])
#print(char in (x[0] for x in chars))

ttf.close()

The script takes as argument the font path?:

python checkfont.py /path/to/font.ttf