Split dividers are hard to see

[david-crespo]

The logic for split divider color (darken bg by 0.08 if dark, otherwise by 0.4) results in barely visible lines, on dark themes especially.

Once I found the code and therefore the name "split divider", I was able to find some discussion about this on Discord. I figure it's worth moving the discussion here. It sounded like the most likely solution is to make the color configurable:

mitchellh: We could easily add a config to modify this color manually

as opposed to, for example, making the logic overly clever.

Example (ayu theme)

There is a horizontal and a vertical divider here, both nearly invisible. With an even darker background, it's totally invisible, because of course darkening black gives you black.

[khaledh]

I'd love to also have the divider width configurable. This is what it looks like in iTerm:

[azasypkin]

Yeah, that would be ideal. With so many people having various color vision deficiencies, it would be really hard to come up with the auto-detectable color for the divider that works for everyone (I couldn’t achieve a satisfactory result for myself with just a color). Offering both configurable width and color should address this for almost everyone.

[oscarvarto]

A contrasting visible line (color configurable) is enough. It would help to avoid eye strain.
I find a too-wide divider very ugly, but others might think differently.

[goproslowyo]

Everyone who's chimed in here so far seems to be on macOS but for the Linux folks that want to adjust this for now use custom css for gtk.

Extreme ugly example to demonstrate:

https://discord.com/channels/1005603569187160125/1322959239693733972/1323020932549312592

[jjt]

mitchellh: We could easily add a config to modify this color manually

going with the Ghostty philsophy of zero-config, might be best to detect the bg color and darken or lighten depending

or could do two tone (if feasible in UI code) of lightened bg line above darkened bg line, like this mockup, might work on any theme?

edit: for horizontal splits, would have the light part on the left, as per humans' preference for top-left lighting, assuming we want the split to appear like a convex "bump" outward - reverse the order for a concave "divot"

[david-crespo]

Surely worth considering, though I suspect it will be hard to come up with logic so good that it doesn't also have to be made configurable.

[lcrespom]

I have a completely black background, so in my case the split divider is completely invisible.
My workaround is to fill the unfocused split with some color:

unfocused-split-fill = #500028

[creechy]

I never really liked how iTerm2 changed the background like this. But not having it (by default) with ghostty, I realize I miss it. Thanks for the tip.

[mitchellh]

Approved manual config #4326.

I'd love to also make the logic for the automatic version better so most people do not have to touch this. I'm just accepting #4326 in the short term so people have an escape hatch. To that end, are there suggestions on how to improve the current formula?

[david-crespo]

Making it configurable isn’t temporary — I think “short term” here means “quick”. He just wants to make it less likely that someone needs to configure it.

[Tener]

To that end, are there suggestions on how to improve the current formula?

How about defaulting to foreground text color (possibly with reduced saturation)? This is a setting that people pay a lot of attention to in their themes and is sure to be highly visible.

[jjt]

foreground color should be for foreground text, not a UI affordance - basing it on some part of the background/chrome/etc seems more appropriate here

configurable setting is definitely needed though, lot of valid and differing preferences 🙂

[J-Siu]

Maybe we can just make it simple as what MacOS is doing with the window border:

If option is not set, and dark theme/background is used, divider is white, else it is black.

Then user can customize it with an option.

[jcollie]

There will be an option to configure the divider color in the next release.