Mode based themes

[eamonno]

Add the following config options.

theme.normal
theme.insert

The logic is that each of these default to the value of theme but if set override the global theme in that mode. The logic should be pretty straightforward to do as it's just replacing the global theme depending on mode.

You could in theory do the same for selects but my understanding is that since selects can be present in either mode it would be all but impossible to make it behave in a way that works on terminals where you don't get to have extra colours and it would be a lot of extra work for little benefit.

[the-mikedavis]

Parts of the theme like the cursor can already be customized by mode: https://docs.helix-editor.com/master/themes.html#interface

It seems unnecessary to me to be able to change the entire theme on mode switch

[eamonno]

I'm aware of the cursor setting at present and it's certainly useful. My own personal preference is to have a different background in insert mode just so it is very clear visually which mode I'm in. So I could have proposed to add a ui.background.insert setting for that, but maybe someone else would like text to be italic in insert mode, or someone else would just like to change the format of the line numbers, or maybe someone wants to change all those things and more. Maybe some degenerate would even like to have a light mode theme in insert mode and a dark mode theme in select mode. Obviously not all of these will be to everyone's taste but I could see a lot of people having different personal preferences. In particular for anyone streaming or teaching helix having a striking visual difference would be very useful for potential viewers. It would also open up the opportunity for theme designers to create custom insert modes. Since so many themes already have multiple colour variants there should already be plenty options though.

Just having a theme override for insert mode seemed like the least work that provides the most functionality. Especially since themes can already specify a base theme it should make it fairly approachable for anyone to tweak their current theme for insert mode.

There is certainly room for debate over whether having things like the cursor insert formatting should be taken out of the base theme and put into a derived theme but I suspect having to have two versions of every theme would feel a bit bloated. I suspect having that setting in the base theme is probably a bare minimum necessary to make working themes for a modal editor (even if some themes don't use them) but I don't really see any downside in allowing people to tweak the visual distinction between modes to their hearts content if they so choose.

[niknbr]

Also, there is a color-modes config to change the color of the mode indicator based on the mode

[editor]
"color-modes" = true

[Necryl]

I also need this, I know we can theme the cursor, but still I sometimes I am forgetting which mode I am in. The background color will be zero cognitive load indicator that yes, you are in normal mode, or insert mode, or select mode. I think this is more than a just cosmetic feature and something that will truly elevate Helix's experience for me.

But on a lower priority note, if we implement this, I hope we can also add semi-transparent backgrounds, because I like to keep the background transparent. A tinted background color change based on the mode would be perfect.