populate-anchors.py

IGNORE_ANCHORS = []

# ----------------------------------------

def match_anchor(anchor_source, anchor_targets):
        if anchor_source.name.startswith("_"):
            target_name = anchor_source.name[1:]
        else:
            target_name = "_" + anchor_source.name
        for a in anchor_targets:
            if a.name == target_name:
                return a

def offset_anchor(anchor, offset):
    """return a copy of the anchor, with the offset applied"""
    out = anchor.copy()
    out.moveBy(offset)
    return out

# ----------------------------------------

f = CurrentFont()

for g in f.selectedGlyphs:
    comp = g.components
    collected_anchors = []
    for c in comp:
        base = f[c.baseGlyph]
        base_anchors = [offset_anchor(a, c.offset) for a in base.anchors]
        collected_anchors.append(base_anchors)

    # filter used anchors
    filtered_anchors = []
    for i, anchors in enumerate(collected_anchors):
        filtered_anchors.append([])
        for a in anchors:

            # locate previous and next component parts
            if i < len(collected_anchors) - 1:
                next_part = collected_anchors[i + 1]
            else:
                next_part = []
            if i > 0:
                prev_part = collected_anchors[i - 1]
            else:
                prev_part = []

            # look behind for matching anchor
            if a.name.startswith("_"):
                match = match_anchor(a, prev_part)
            # look ahead for matching anchor
            else:
                match = match_anchor(a, next_part)

            # collect only non matching anchors
            if not match:
                filtered_anchors[-1].append(a)
    collected_anchors = filtered_anchors

    for anchors in reversed(collected_anchors):
        for anchor in anchors:
            if anchor.name not in [a.name for a in g.anchors] and anchor.name not in IGNORE_ANCHORS:
                g.appendAnchor(anchor.name, anchor.position)