Add buildTextureFeature for texture healing support

[joemouk]

Hello @protesilaos!

Thank you for Aporetic! The combination of mono and proportional variants with a unified design makes it ideal for literate programming.

I'm wondering if you'd consider adding buildTextureFeature = true to the build plans? This would expose Iosevka's experimental texture healing feature (added in v27.3.5) via the TXTR OpenType tag, which helps even out the visual density of monospaced text.

Happy to help test if useful. Thanks for considering!

[protesilaos]

Hello @joemouk!

I remember reading about this a while ago. It looks promising, though I did not try it out of concern that it would break the fonts in subtle ways. But reading this again, I think I originally misunderstood how it works: this is always an opt-in feature that you set via the OpenType tag? If so, then I see no problem having it enabled.

That granted, I will have to do this the next time I build the fonts.

[protesilaos]

That granted, I will have to do this the next time I build the fonts.

But you do not have to wait for me. You can build the fonts locally if you want. I have a note about this in the README, but am happy to help you with any questions.

[joemouk]

Thanks so much, @protesilaos ! Really appreciate you adding this.

To confirm: yes, TXTR is opt-in. Building with buildTextureFeature = true adds the feature to the font, but it's inactive by default — users must explicitly enable it via OpenType settings (e.g. font-feature-settings: "TXTR" 1 in CSS).

Regarding your concern about subtle breakage: there was a bug with slab builds back in July 2024, but it was fixed the same day. There was also a fix for Kitty terminal clipping of texture-extended glyphs. So things should be stable now.

I'll try a local build in the meantime. Thanks again!

[protesilaos]

I'll try a local build in the meantime. Thanks again!

Very well! Then we can include it in the next build. Before I do that though, I need to review all the changes in iosevka.git to confirm there is no breakage (this has happened in the past, which glyphs getting new codenames).

[joemouk]

Wonderful — thank you, @protesilaos! Really appreciate your careful approach to quality.