The aalt feature seems to be enabled by default

[fredizzimo]

For the full context check this Neovide issue

• PragmataPro Mono rendered as some kind of german font neovide/neovide#2786

But in short, the font PragmataPro Mono enables these features when aalt is enabled, and that combination looks exactly like the screenshot provided.

feature aalt {
  feature fina;
  feature medi;
  feature init;
  feature ss03; ← Fraktur
  feature ss04; ← Fraktur Bold
  feature ss05; ← Poker symbols with lines above and bottom
  feature ss06; ← Script
  feature ss07; ← Script Bold
  feature ss08; ← Serif Bold
  feature ss09; ← Serif Italic
  feature ss10; ← Serif Bold Italic
  feature ss11; ← Braille
} aalt;

The issue is that Neovide does not enable aalt, and the font does not have it enabled by default either. Still Swash thinks it's enabled, until we explicitly disable it with -aalt

One of my theories is that the support for font features with TrueType fonts is a bit broken, since we have not seen any similar reports for any other fonts. But that's just a guess. and I decided not to debug it further for the moment, since the font is not free.

Do you have any ideas what could cause it?

[griffinwxk]

Per @fredizzimo 's request, I attach the testing code I did some time ago using swash_demo:

I added the following near the end of main.rs, right before db.build()

db.enter_span(&[S::family_list("PragmataPro Mono Liga"), S::Weight(Weight::BOLD)]);
db.add_text("\n\nDoes this BOLDING work?");
db.leave_span();

db.enter_span(&[S::family_list("PragmataPro Mono Liga"), S::Style(Style::Italic)]);
db.add_text("\n\nDoes this Italic work?");
db.leave_span();

The result is this:

Oddly enough, when I use the non-Liga version (using the font family "PragmataPro Mono" instead), the fonts renders fine. Same results for non-Mono versions: Liga = problem, non-Liga = good.

It doesn't completely match the behavior in neovide though. In neovide, every combination of (non-)Mono/(non-)Liga seems to be rendered wrong.

I use the latest release of PragmataPro (0.830 I think).