It is a Opentype question which is not related to Glyphs app. Do you know if it is possible to substitute for example two glyphs by three glyphs?
I have managed to change one by multiple or multiple by multiple as long as are equal numbers (for example three by three).
Two possible ways:
- Two separate substitution lookups: first a ligature,
a_b, then a one-to-many lookup,
a b c.
- A chaining contextual lookup, in which you call a lookup with one-to-many substitutions like
sub x y' lookup ONE2MANY;and the lookup
ONE2MANYis defined in the prefix and contains subs like
sub y by y z;.
Thanks! it’s not ideal but I will manage with the first option.