Ligatures Substitution rules cause an offset overflow

HI George
i’m using Glyphs Version 2.6.5 (1339)
I have an error already and I resolve it59%20AM

There is way too much in you (handwritten) features, either in calt or in one of the features that come before. You need to reduce the substitution rules or recode them in a more efficient way. Consider a smarter way of organizing lookups, consider useExtension flags, but you will have to reduce the amount of sub rules one way or another.

ok, i got your point

Promblem resolved, thanks george, mekkablue

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Can you share what you did to solve it? (For people who have the same issue in the future.)

Following up on this old thread because I have a similar issue working with the Material Design Icons font (material-design-icons/MaterialIcons-Regular.ttf at master · google/material-design-icons · GitHub). A few years ago, I added some glyphs, updated the liga with a few substitution rules and it exported fine.

When I tried it again today, I’m getting these same ‘offset overflow’ errors. I’m running Version 2.6.6 (1349) on a Mac with 10.13.6 (17G14033). Unfortunately, I can no longer update this aging workhorse :frowning:.

Has something changed in subsequent Glyphs updates that would affect this? by its nature there’s ~980 lines of code for liga and ~1570 lines of code for rlig in this icon font.

Apart from eliminating lines of code, is there anything else that can be done?


The font from the repo imports and export fine. Can you send me your file that I can have a look.

And why do you have stuff in rlig and in liga? maybe reuse some lookups?

I sent a PM, but I also tried to just export the repo file and received this error… I had received this error before and removed the duplicate reference to ‘s t a r underscore…’

And now it exported just fine.

I’ll just migrate my updated glyphs to this new file. Something must have just been corrupted.

Thanks for all your help!!


How do you select the alternate glyphs?

And you can split the rules into several lookups. That might help with the overflow.