feature: Improve background colors of signs highlight groups

[kmoschcau]

Is your feature request related to a problem? Please describe.

Currently it looks like the signs added by this plugin use the background color of the Normal highlight group. This leads to effects like this:

Describe the solution you'd like

Here are three possible solutions:

• Do not set a background color for the signs.
• Use the background color of the SignColumn highlight group instead.
• Provide a way to configure the sign highlight groups separately.

[MeanderingProgrammer]

Thanks for bringing this up, that is definitely unexpected.

The signs added by this plugin don't add a background highlight group.

In the case of code we use only the highlight group returned from the icon provider. So in the case of mini.icons & python we get MiniIconsYellow and only set that: https://github.com/MeanderingProgrammer/markdown.nvim/blob/main/lua/render-markdown/handler/markdown.lua#L92-L101

Then in the case of headings we use only the value of the foreground highlight group: https://github.com/MeanderingProgrammer/markdown.nvim/blob/main/lua/render-markdown/handler/markdown.lua#L37-L59

In both of these cases we do not add Normal as a background.

I've played around with a few other color schemes and am unable to replicate the background being different, though I can clearly see it in your screenshot. What colorscheme do you use?

[kmoschcau]

I use my own theme, which I generate with this lua tool. For the icons I'm using mini.icons, which has highlight groups with only a foreground color defined.

Also there's no such thing really as background and foreground highlight groups. Highlight groups can have both a foreground and background color. If you'd want to make sure to only use the foreground color of an existing highlight, you'd need to extract that from the highlight group.

[MeanderingProgrammer]

Yeah, I call them foreground since the highlights seem to only define guifg (at least for me).

Which icon provider are you using?

If it's mini.icons then the highlight group for python resolves to MiniIconsYellow which for me only has a guifg defined.

If it's nvim-web-devicons then the highlight group for python resolves to DevIconPy which only has ctermfg and guifg defined.

I'm just rather lost on how a background is getting set on these icons for you. Is there some fallback logic happening somewhere? As far as I'm aware the solution Do not set a background color for the signs. is already the case.

[kmoschcau]

I use mini.icons. And I just checked myself: MiniIconsYellow only has guifg and ctermfg.
It's a bit difficult to inspect the final result. I could just use :Inspect, if it was in a buffer, but for signs I'd need some other way.

I just looked through my tool again and tested a bit: Signs highlight groups do not behave different from other highlight groups. Anything that's not specified for a highlight group falls back to what's specified for Normal. Meaning, for signs you have to specifically set the background to match that of the SignColumn highlight group. That's what I do for all sign highlights I have defined.

[MeanderingProgrammer]

Ah, I was wondering why I wasn't able to get something to display this behavior. Turns out that most color schemes use the same background color for Normal as SignColumn. Found one that doesn't and now see the same thing, will work on a fix, probably need to create some custom merged highlights.

[MeanderingProgrammer]

Added the logic to use the SignColumn background here: d398f3e

Please update and lmk if it looks better!

Also added the ability to disable signs on specific buftypes, defaults to nofile. Will follow up in the other thread with that.

[kmoschcau]

Yep, that works like a charm!

[MeanderingProgrammer]

Sweet! Btw for the optional fields there's an equivalent type called 'render.md.UserConfig'. I have a script to generate one from the other so they stay in sync.

[kmoschcau]

Ah! Good to know. I admit it was a subtle attempt to get it fixed or info on how to improve it on my side. 😄
Thanks again for all the work you put in. This is really a great plugin.