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Enable dark mode for kitty, fish, Neovim

Published on: 25 Jan 24

vim fish

This is for me. This article/note is for me. What do I want to write for myself in a few months.

(modify as this is what I thought) We’ll I’ve come to realize Dark Mode is great but during the day in sunny areas I have to adjust brightness or haphazardly change terminal themes that do not get propagated to everywhere making the whole situation even more annoying. Its time to fix this.

After a few searches I stumbled on a post detailing how to toggle between light/dark themes for fish, kitty, and neovim. The main idea is to define a pair of functions: light.fish and dark.fish to toggle the correct themes for tools.

Main tools I’m concerned with are Fish, Kitty, and Neovim. Fortunately all these tools come with prefigured styles and huge communties around styling. For this I decided to switch to a new to me theme of catppucin but easily available for most apps.

🐈 Kitty

Kitty has tooling for themes and preinstalled out of the box. Run:

kitty +kittens themes

I’m using catppucin-mocha as my dark mode.

🐠 Fish

Fish also comes with pre-baked themes, for themes run this show a preview of all themes with a code sample. Here we are mainly just looking for some that is readable:

fish_config themes show

For me fish default looks the best so I’ll just keep it.

🖥️ Neovim

Neovim themes are controlled via init.lua so have to add a few lines to script. This will work based on a conditional THEME variable:

-- Set the colorscheme to catppuccin-mocha using a protected call
-- in case it isn't installed
if os.getenv('theme') == 'light' then
  local status, _ = pcall(vim.cmd, "colorscheme catppuccin-mocha")
  if not status then
    print("Colorscheme not found!") -- Print an error message if the colorscheme is not installed
    return
  end
end

(init.lua)

🎁 Wrap this a function

function dark --description 'Enables a dark theme for Fish, Nvim, and Kitty'
  # Set theme for Nvim
  set -xU THEME dark

  # Set theme for Bat
  set -xU BAT_THEME "TwoDark"

  # Set theme for Kitty
  kitty +kitten themes catppuccin-mocha
end

🎉 Bonus: configure a readable theme for bat.

The cat alternative bat has a --theme flag and also uses BAT_THEME="..." which we can configure. It also comes with an option list all themes bat --list-themes.

...
Theme: OneHalfLight

  // Output the square of a number.
  fn print_square(num: f64) {
      let result = f64::powf(num, 2.0);
      println!("The square of {:.2} is {:.2}.", num, result);
  }

Theme: ...

Add theme to functions:

# Set theme for Bat
set -xU BAT_THEME "OneHalfLight"

Repeat the steps to create an equivalent light.fish function. You should now be able to toggle between dark and light modes.

I want to seamlessly toggle between light/dark modes for Fish, Kitty, and Neovim.

I’m thinking two separate Fish functions: light and dark

First step is to set a Fish light theme. Fish comes preconfigured with several themes.

Find a Kitty theme that works with this.

Update neovim theme.

Wrap this a fish function

Repeat for dark theme

Start with updating Fish themes.

Define a base light theme for fish

Bonus: Change theme for Bat (cat with wings)