twardoch/fonttools-opentype-feature-freezer

Should freezing still leave the features togglable?

Opened this issue · 4 comments

madig commented

If I freeze ss01 in a font, should toggling it do the reverse?

I think this was once the case but I might be misremembering...

I think it would make sense. This would of course require reversing the sub rules. In my initial implementation I only remapped the Unicodes, so the original encoded glyphs are orphaned.

But if you do modify GSUB, make it optional. I use the freezer to build TTCs: Basically, alternative cmap & name tables are added as extra "font API" tables but the rest remains the same. This makes the TTC only negligibly larger than the original font. But with changed GSUBs, this would increase the size a lot.

madig commented

Mh. Wouldn't it be enough to swap the sub ... by ... lookups inside the feature? 🤔

Yeah, that's what I mean. I've never done this and if you feel like doing it, please kindly make this optional (onable or offable, I don't care) for the TTC reasons ☺️

madig commented

Just wondering, would it increase TTC size because you might not want to apply it to all contained fonts?