Save UFO2 files from Robofont 3

rf_ufo3_to_ufo2.py

import os
from defcon import Font


def remap_item_name(name):
    '''
    Remaps a single item name from public.kern style to @MMK style
    '''
    if 'public.kern1.' in name:
        return name.replace('public.kern1.', '@MMK_L_')
    elif 'public.kern2.' in name:
        return name.replace('public.kern2.', '@MMK_R_')
    else:
        return name


def remap_groups(groups):
    '''
    Remaps groups dictionary to not contain
    public.kern prefixes.
    '''
    remapped_groups = {}
    for group_name, glyph_list in groups.items():
        remapped_group_name = remap_item_name(group_name)
        remapped_groups[remapped_group_name] = glyph_list

    return remapped_groups


def remap_kerning(kerning):
    '''
    Remaps kerning dictionary to not contain
    public.kern prefixes.
    '''
    remapped_kerning = {}
    for (left, right), value in kerning.items():
        remapped_pair = (
            remap_item_name(left),
            remap_item_name(right))
        remapped_kerning[remapped_pair] = value

    return remapped_kerning


f = CurrentFont()
ufo_folder, ufo_name = os.path.split(os.path.abspath(f.path))
ufo_basename, ufo_suffix = os.path.splitext(ufo_name)
ufo2_name = '{}_UFO2{}'.format(ufo_basename, ufo_suffix)
ufo2_path = os.path.join(ufo_folder, ufo2_name)

df = Font(f.path)
df.save(ufo2_path, formatVersion=2)

df2 = Font(ufo2_path)

# revert groups and kerning to UFO2 style
ufo_2_groups = remap_groups(df2.groups)
ufo_2_kerning = remap_kerning(df2.kerning)

df2.groups.clear()
df2.kerning.clear()

df2.groups.update(ufo_2_groups)
df2.kerning.update(ufo_2_kerning)

# revert mark color to Robofont UFO2 style
marked_glyphs = [g for g in df2 if 'public.markColor' in g.lib.keys()]
for g in marked_glyphs:
    mark_str_list = g.lib['public.markColor'].split(',')
    mark_val_list = [eval(v) for v in mark_str_list]
    g.lib['com.typemytype.robofont.mark'] = mark_val_list
    del g.lib['public.markColor']

df2.save()