Toggle Metrics Machine pair list

mm_toggle.py

'''
Toggle the pair list of an open MetricsMachine (extension) window
from all kerning pairs (sorted by glyph order) to exceptions and back.

'''

import metricsMachine
import mm4
f = CurrentFont()


def get_exception_pairs(f, kerning_pairs):
    '''
    Find kerning exceptions.

    '''

    exceptions = []
    groups_l = [gr for gr in f.groups.keys() if gr.startswith('public.kern1')]
    groups_r = [gr for gr in f.groups.keys() if gr.startswith('public.kern2')]
    grouped_l = sum([list(f.groups.get(gr)) for gr in groups_l], [])
    grouped_r = sum([list(f.groups.get(gr)) for gr in groups_r], [])

    for pair in kerning_pairs:
        left, right = pair
        if any([left in grouped_l, right in grouped_r]):
            exceptions.append(pair)
    return exceptions


def get_repr_glyph(item_name, glyph_order):
    '''
    Get a representative glyph name for a given group.
    The level of importance is deduced by the glyph’s position in the
    glyph order: lower = better

    In addition to the above, symmetrical glyphs like O, H will be preferred
    over group members like D, C, B, E, etc.

    '''
    symmetrical = 'HOno'
    glyph_list = f.groups.get(item_name, [item_name])
    sorted_glyph_list = sorted(glyph_list, key=lambda g: glyph_order.index(g))

    for gname in sorted_glyph_list:
        if gname.split('.')[0] in symmetrical:
            return gname

    return sorted_glyph_list[0]


glyph_order = f.glyphOrder
mm_all_pairs = []
mm_all_pairs_flipped = []
mm_exc_pairs = []

sorted_kerning = sorted(
    f.kerning.keys(), key=lambda p:
        (
            glyph_order.index(get_repr_glyph(p[0], glyph_order)),
            glyph_order.index(get_repr_glyph(p[1], glyph_order))))

sorted_kerning_right = sorted(
    f.kerning.keys(), key=lambda p:
        (
            glyph_order.index(get_repr_glyph(p[1], glyph_order)),
            glyph_order.index(get_repr_glyph(p[0], glyph_order))))


for pair in get_exception_pairs(f, sorted_kerning):
    left, right = pair
    mm_exc_pairs.append((
        get_repr_glyph(left, glyph_order),
        get_repr_glyph(right, glyph_order)))


for pair in sorted_kerning:
    left, right = pair
    mm_all_pairs.append((
        get_repr_glyph(left, glyph_order),
        get_repr_glyph(right, glyph_order)))
for pair in sorted_kerning_right:
    left, right = pair
    mm_all_pairs_flipped.append((
        get_repr_glyph(left, glyph_order),
        get_repr_glyph(right, glyph_order)))


if mm_exc_pairs:
    pair_lists = [mm_all_pairs, mm_exc_pairs, mm_all_pairs_flipped]
else:
    pair_lists = [mm_all_pairs_flipped, mm_all_pairs]

try:
    current_pairlist = metricsMachine.GetPairList()
    if current_pairlist in pair_lists:
        cp_index = pair_lists.index(current_pairlist)
    else:
        cp_index = 0
    next_pairlist = pair_lists[(cp_index + 1) % len(pair_lists)]
    # if metricsMachine.GetPairList() == mm_all_pairs:
    #     metricsMachine.SetPairList(mm_exc_pairs, f)
    # else:
    metricsMachine.SetPairList(next_pairlist, f)


except mm4.mmScripting.MetricsMachineScriptingError:
    print(
        'Please open Metrics Machine! '
        '(I don’t know how to do that in a script)')