Robofont script to reset a composite glyph according to the anchor found in the base glyph.

glyph_recompose_according_to_anchor.py

import math


def largest_component(g):
    if not g.components:
        return
    else:
        boxList = []
        for c in g.components:
            boxList.append(
                (
                    math.hypot(c.box[2] - c.box[0], c.box[3] - c.box[1]),
                    g.components.index(c)
                )
            )
    return max(boxList)[1]


f = CurrentFont()
g = CurrentGlyph()


def reset_accent_to_anchor(g):
    main_component_index = largest_component(g)
    if main_component_index is not None:
        g.prepareUndo('recompose according to anchor')
        main_component = g.components[main_component_index]
        base_g_name = main_component.baseGlyph
        base_glyph = f[base_g_name]

        accent_components = [
            c for c in g.components if not c.baseGlyph == base_g_name]
        template_anchor_dict = {
            anchor.name: anchor.position for anchor in base_glyph.anchors}
        for accent_component in accent_components:
            accent_glyph = f[accent_component.baseGlyph]
            accent_anchor_dict = {
                anchor.name: anchor.position for anchor in accent_glyph.anchors}
            for a_name, a_position in list(accent_anchor_dict.items()):
                target_position = template_anchor_dict.get(a_name[1:])
                if target_position:
                    current_offset = accent_component.offset
                    current_anchor_position = (
                        a_position[0] + current_offset[0],
                        a_position[1] + current_offset[1],
                    )
                    offset = (
                        target_position[0] - current_anchor_position[0],
                        target_position[1] - current_anchor_position[1]
                    )
                    accent_component.moveBy(offset)
        g.performUndo()

reset_accent_to_anchor(g)