Question: how to deal with non-monospace ligatures?

[AckslD]

I'm wondering how to deal with long ligatures since they are effectively not monospace? For example underlines of headers in markdown:

or simply trying to draw some boxes in ascii:

(the character before the right +s is a - even though it looks like a )

I'm using latest ttf-fira-code from the arch repository in neovim 0.5

[tonsky]

I'm not sure what’s causing that in your case. For me they are monospace (Fira Code 5.2 in Sublime Text on macOS):

[AckslD]

That looks much better :) I'm using kitty btw, should have probably mentioned that. I tried to see what's going with running it with --debug-font-fallback. It's hard to see what is what but it does sometimes fallback, for example this is the start:

> kitty --debug-font-fallback
[175 15:14:54.255153] Preloaded font faces:
[175 15:14:54.255177] normal face: /usr/share/fonts/TTF/FiraCode-Regular.ttf:0
[175 15:14:54.255187] bold face: /usr/share/fonts/TTF/FiraCode-Bold.ttf:0
[175 15:14:54.255195] italic face: /usr/share/fonts/TTF/FiraCode-Regular.ttf:0
[175 15:14:54.255203] bi face: /usr/share/fonts/TTF/FiraCode-Bold.ttf:0
U+f3e2 Face(family=Font Awesome 5 Brands, style=Regular, ps_name=FontAwesome5Brands-Regular, path=/usr/share/fonts/TTF/fa-brands-400.ttf, index=0, is_scalable=True, has_color=False, ascender=448, descender=-64, height=558, underline_position=-49, underline_thickness=25, strikethrough_position=132, strikethrough_thickness=25) (new face)
U+f126 Face(family=Font Awesome 5 Free, style=Solid, ps_name=FontAwesome5Free-Solid, path=/usr/share/fonts/TTF/fa-solid-900.ttf, index=0, is_scalable=True, has_color=False, ascender=448, descender=-64, height=558, underline_position=-49, underline_thickness=25, strikethrough_position=132, strikethrough_thickness=25) (new face)
U+2714 Face(family=FreeSerif, style=Regular, ps_name=FreeSerif, path=/usr/share/fonts/gnu-free/FreeSerif.otf, index=0, is_scalable=True, has_color=False, ascender=900, descender=-200, height=1200, underline_position=-150, underline_thickness=50, strikethrough_position=258, strikethrough_thickness=49) (new face)

[cormullion]

I've read that Kitty draws its own boxes, and ignores the ones provided by the font. You could investigate this the truth of this with the Kitty dev...

[AckslD]

Thanks @cormullion! I opened an issue in the kitty repo to see if anyone have some insight into this. I'm afraid I have to little knowledge about font rendering to know how to test it or see if there is a solution :)

[AckslD]

@tonsky Where you using drawing characters https://en.wikipedia.org/wiki/Box-drawing_character in you case or normal ones, ie:

+----------------+
|                |
|  +----------+  |
|  |          |  |
|  |  +----+  |  |
|==|==|    |==|==|
|  |  +----+  |  |
|  |          |  |
|  +----------+  |
|                |
+----------------+

[tonsky]

These are normal ASCII dash, pipe, plus and equals sign

[AckslD]

The developer of kitty said that:

Those arent issues with box drawing characters, those are issues with the new infinite length ligatures in fira code not lining up with the non-ligature glyphs. If you want to draw boxes, use the actual box drawing charaters https://en.wikipedia.org/wiki/Box-drawing_character

Infinite length ligatures are not really a substitute for actual box drawing characters, precisely because there is no longer any guarantee they will line up.

[tonsky]

Well they do line up everywhere but in Kitty ¯\ (ツ)/¯

[AckslD]

@tonsky I just tried using https://aur.archlinux.org/packages/alacritty-ligatures/ and there they indeed line up, so closing this since it seems to indeed be an issue with kitty. Thanks for the help!