A RoboFont script to expand kerning groups from base glyph to their composites.

expand-groups-to-components.py

from simpleKerning import *
"""
A RoboFont script to expand kerning groups from base glyph to their composites.

1. Select the composites which are not grouped
2. Run the script
3. The groups will be expanded to the composites, if:
	- Their width is same as the base glyph
	- They're not already grouped
"""

def getComps(glyphName, compMap):
	"""
	Get all the related components **recursively**.
	"""
	result = set()
	inputGlyphs = set([glyphName])
	while inputGlyphs:
		glyphName = inputGlyphs.pop()
		comps = compMap.get(glyphName, set()) - result - inputGlyphs
		if comps:
			result.update(comps)
			inputGlyphs.update(comps)
	return result

def expandKerningGroupsFromBaseGlyphs(f, selection):
	"""
	Selection should be the composites.
	"""
	groups = f.groups
	glyphToGroupMap = getGlyphToGroupDictionary(groups)
	newGroups = dict(groups)
	for compositeGlyph in selection:
		compositeGroups = glyphToGroupMap.get(compositeGlyph.name, [])
		if compositeGroups:
			continue
		for c in compositeGlyph.components:
			if c.baseGlyph in glyphToGroupMap:
				baseGlyph = f[c.baseGlyph]
				baseGlyphGroups = glyphToGroupMap.get(baseGlyph.name, [])
				baseGlyphWidth = baseGlyph.width
				if compositeGlyph.width == baseGlyphWidth:
					# success
					for gr in baseGlyphGroups:
						members = list(newGroups[gr])
						members.append(compositeGlyph.name)
						newGroups[gr] = members
					compositeGlyph.markColor = (0.3364, 0.9951, 0.5913, 1)
					baseGlyph.markColor = (0.3364, 0.9951, 0.5913, 1)

	f.groups.clear()
	f.groups.update(newGroups)

if __name__ == '__main__':
	f = CurrentFont()
	selection = f.selectedGlyphs
	expandKerningGroupsFromBaseGlyphs(f, selection)