Deleting kernigpairs with 0 (zero) as value

Glyphs
21

I noticed that when you delete the zero pairs needed to make exceptions, that the exceptions become class kerning

22

Did you use ‘Compress’? Or just delete the zero pairs? I’ve had this situation:

/iogonek /@MMK_R_j -50
which is an ‘exception’ and no kerning between:
/@MMK_L_i /@MM_K_R_j

where /ogonek is in class@MMK_L_i

It was fine, I didn’t have /@MMK_L_i /@MM_K_R_j 0 . I noticed if you use Compress though it will turn /iogonek /@MMK_R_j -50 into /@MMK_L_i /@MM_K_R_j -50 which is wrong.

23

this is what Compress is supposed to do. If you have exceptions like that you can’t use Compress.

24

Is this still true? That is going to turn any non class kerning without a class kerning of zero into the class kerning…?

25

Of course. What else should it do?

26

I was just concerned about when there was no base kerning… like /i/l being 0 but /idieresis/l having +10 for example then /i/l becomes +10, I realise Glyphs doesn’t know whether any glyph in a kerning group is the ‘base glyph’…

27

There is no base glyph. Only the name of the class that might be mistaken for the ‘key glyph’.

And you describe the main problem that can arise when using the compress function.