Simple creation of accented glyphs in/for Fontra

simple_accented_glyphs.py

'''
Command-line script to add accented glyphs to a UFO, based on glyph names and anchors existing in the font
ss_dummy.ufo
'''

from fontParts.fontshell import RFont
from fontTools import agl

def anchor_offset(base_anchor_name, base_glyph, mark_glyph):
    '''
    calculate the offset between anchor pairs in base- and mark glyph
    '''
    base_anchors = {anchor.name: anchor.position for anchor in base_glyph.anchors}
    mark_anchors = {anchor.name: anchor.position for anchor in mark_glyph.anchors}

    mark_anchor_name = f'_{base_anchor_name}'
    if base_anchor_name in base_anchors and mark_anchor_name in mark_anchors:
        base_position = base_anchors.get(base_anchor_name)
        mark_position = mark_anchors.get(mark_anchor_name)
        return base_position[0] - mark_position[0], base_position[1] - mark_position[1]


base_glyph_names = 'abcdefghijklmnopqrstuvwxyz'
mark_glyph_names = [
    'gravecmb', 'acutecmb', 'circumflexcmb', 'tildecmb', 'macroncmb',
    'brevecmb', 'dotaccentcmb', 'dieresiscmb', 'ringcmb', 'hungarumlautcmb',
    'caroncmb', 'commabelowcmb', 'cedillacmb', 'ogonekcmb']
anchor_names = ['aboveLC', 'belowLC', 'ogonek']

# dictionary of glyph names to code points
agl2uv = agl.AGL2UV
f = RFont('ss_dummy.ufo')

for base_name in base_glyph_names:
    base_glyph = f[base_name]
    for mark_name in mark_glyph_names:
        mark_glyph = f[mark_name]
        g_name = f'{base_name}{mark_name.replace("cmb", "")}'
        codepoint = agl2uv.get(g_name, None)
        if codepoint and g_name not in f.keys():
            for anchor_name in anchor_names:
                offset = anchor_offset(anchor_name, base_glyph, mark_glyph)
                if offset:
                    ng = f.newGlyph(g_name)
                    ng.unicode = codepoint
                    ng.appendComponent(base_name)
                    ng.appendComponent(mark_name, offset)
                    ng.width = base_glyph.width

# this even will refresh the open font in Fontra
f.save()