Add an avar table to a variable font

add_avar.py

"""
Add an avar table to a VF font. This is often needed for VF fonts generated with glyphsapp

Please note: this script requires the same dependencies as fontmake, https://github.com/googlei18n/fontmake

For testing avar table see script, https://github.com/googlefonts/gftools/blob/master/bin/gftools-check-vf-avar.py

TODO (GF team) File issue on Glyphsapp if glyphsapp does not generate avar table by default.


How to use:

python add_avar.py family.glyph family-Roman-VF.ttf


"""
from fontTools.varLib import _add_avar, load_designspace
from fontTools.ttLib import TTFont
import glyphsLib
import sys

if len(sys.argv) != 3:
    raise Exception('Include path to .glyphs source and VF tff e.g.\n\n python add_avar.py family.glyph family-Roman-VF.ttf')

glyphs_path = sys.argv[1]
font_path = sys.argv[2]
ttfont = TTFont(font_path)


font = glyphsLib.GSFont(glyphs_path)
designspace = glyphsLib.to_designspace(font)

designspace_filename = 'temp.designspace'
designspace.write(designspace_filename)

axes, internal_axis_supports, base_idx, normalized_master_locs, masters, instances = load_designspace(designspace_filename)

_add_avar(ttfont, axes)

ttfont.save(font_path+'.avar')