Hi,
I have a MM font with kerning classes in GLyphs. The kerning of each individual master is produced in an external app, in FL. In FL I have around 700 kerning pairs. Then kerning is expanded, each master is exported as individual UFO, imported to Glyphs and from there copy-pasted into the MM file into the corresponding master.
So now I have 4 masters with around 15.000 kerning pairs. I press compress to adapt my kerning pairs to my GLyphs kerning classes. After I press compress once I get around 4000 pairs and kerning (seems to) work ok. If I press compress again I get around 800 but the kerning doesn t work correctly and I have the feeling that kerning classes and spacing classes get messed up.
For example for ‘k’ glyph I use ‘n’ as a metric class but ‘h’ as a kerning class. So after I press compress for the second time all the glyphs contained in the ‘h’ kerning class get the same kerning as glyphs in ‘n’ metric class so for example I get an overlap in the combo ‘Th’ while ‘Tn’ works fine.
I do not know if I m doing a wrong methodology to import external kerning, if I m doing something wrong or if I am reporting a bug. What does that second compress step do??