Subtable offset too large


I’m working on an experimental font with with a very large amount of sub and ignore sub statements and for a while now I’ve been confronted with messages like: subtable offset too large (10172) in lookup 0 type 1.

I’ve been able to get around it this previously by finding efficiencies in my code and using useExtension for lookups, but the message eventually returns as I continue to add to the font.

Most of the answers I’m finding on this forum are for similar issues with kerning but what I’m seeing appears to be speciffically to do with sub and ignore sub statements.

I’m wondering if there is a physical limit to the amount of statements a font file can contain or if this is a limitation of the Glyphs app. Guessing it is the former but have to ask.

It’s not the end of the world If I can’t include more statements in my font but it would make it much better if I could.

Any workarounds or advice would be much appreciated.

It is very rare to see an overflow in a GSUB table. You need a lot code to do that.

Have you tried splitting the lookups.

There is certainly a lot of code in going on. I’ve tried several ways of dividing the code between lookups but with no success.

I’ve emailed support to explain what I’m tying to achieve.

I’m having the exact same issue as you. I’ve just tried rewriting my code without ‘ignores’, but I’ve just hit the ‘subtable overflow’ again with around 2,000 or so lines of code… and I’m just getting started. I can definitely utilize more lookups, but I’m wondering if you found a solution that worked for you?

Have you tried to use extension lookups?

Thank you for responding Georg. I actually found MakeOTF GSUB offset overflow and so far splitting my liga features into two lookups is working for me. I’ve been able to keep adding code for a while now.