UNSOLVED Fontparts, Kerning groups and performance.

  • Hi, everyone!
    Since this is not strictly related with RF but Fontparts, I don’t know If here is the correct place to post this. I hope to not be spamming.

    I made a quick script to change kerning groups and it works on most of the cases, but it hungs up if the font is really big.

    I really don’t know if I’m doing it correctly. So any help is really appreciated.

    here a sample code:

    from fontParts.world import *
    fontPath = 'myFont.ufo'
    font = OpenFont(fontPath, showInterface=False)
    glyphs = font.keys()
    def removeGlyphFromKerningGroups(glyph):
        currentGroups = font.groups.findGlyph(glyph.name)
        for groupName in currentGroups:
            group = font.groups[groupName]
            groupList = list(font.groups[groupName])
            font.groups[groupName] = tuple(groupList)
    def getKerningGroups(glyphName, side):
        if side == 1:
            groups = font.groups.side1KerningGroups
            groups = font.groups.side2KerningGroups
        glyphGroups = []
        for key in groups:
            for value in groups[key]:
                if glyphName == value:
        return glyphGroups
    for thisGlyphName in glyphs:
        thisGlyph = font[thisGlyphName]
        if thisGlyphName.endswith(".sc"):
            basename = thisGlyphName.split(".")[0]
            side1Groups = getKerningGroups(basename, 1)
            for side1Group in side1Groups:
                kern1Group = font.groups[side1Group]
                kern1GroupList = list(kern1Group)
                font.groups[side1Group] = tuple(kern1GroupList)
            side2Groups = getKerningGroups(basename, 2)
            for side2Group in side2Groups:
                kern2Group = font.groups[side2Group]
                kern2GroupList = list(kern2Group)
                font.groups[side2Group] = tuple(kern2GroupList)   
            currentGroups = font.groups.findGlyph(thisGlyph.name)
            print (thisGlyph.name, currentGroups)

    Thanks in advance.

  • admin

    explain 'hung' is there a traceback? do you end up in an endless loop

    can you provide an dummy ufo where this happens?

  • admin

    a tip about performance: if you are making a lot of edits, it’s faster to work on pure Python objects and then save the result back into the font when you’re done.

    you can get a font’s groups as a dict with font.groups.asDict()

    hope that helps!

  • Hi @frederik It just never ends, no tracebacks. If I don’t manage to solve it with @gferreira tip I will try to prepare a dummy ufo and post it here. Thank you both!