I work on the Cantonese Font, where one of the features is to use a notation like 車.geoi1 to trigger a ligature rule, swapping to a different glyph.
(L:
車, R: 車.geoi1; displayed with Apple CoreText)
Some font shapers first split text into language runs, and 車.geoi1 is split into 車 and then .geoi1, never triggering the ligature.
I noted that Glyphs provides a way to designate script for a glyph, which would be handy for me to preserve these ligatures in the same text run:
but this has no effect upon export: open up the exported .ttf in Glyphs, and the modified parameter reverts to Latin.
Is there a flag that enables glyphs with modified Script to have this parameter exported? If not, is there a way to achieve the same effect (ligatures across mixed scripts)?