MarkToBase RSB Export Error

Glyphs
1

Hi All

As a bit of housekeeping, I tidied up the RSB of all my combining marks, setting them all to zero. However, I now get the export error:

MarkToBase lookup subtable in GPOS feature ‘mkmk’ causes offset overflow.

I have four types of comb marks for caps, lowercase and smcp, mid caps. I though the side-bearings were removed on export. Is there any way to correct?

2

As an update, I removed all anchors and the file exported ok.
I reset anchors (command+U) in just my uppercase but then export caused this fatal error:

ClassDef offset overflow (0x10320) in pair positioning

MarkToBase lookup subtable in GPOS feature ‘mkmk’ causes offset overflow.

Any thoughts?

3

That means you have to much kerning and/or mark positioning. You can try to use the “Use Extension Kerning” parameter.

4

OK, thanks
It’s probably as side effect of the font is getting quite big.