True Color (24-bit) and italics with alacritty + tmux + vim (neovim)

alacritty-tmux-vim_truecolor.md

True Color (24-bit) and italics with alacritty + tmux + vim (neovim)

This should make True Color (24-bit) and italics work in your tmux session and vim/neovim when using Alacritty (and should be compatible with any other terminal emulator, including Kitty).

Testing colors

Running this script should look the same in tmux as without.

curl -s https://gist.githubusercontent.com/lifepillar/09a44b8cf0f9397465614e622979107f/raw/24-bit-color.sh >24-bit-color.sh
bash 24-bit-color.sh

Configuration files

⚠️ IMPORTANT ⚠️ Don't set $TERM in your shell (zshrc, bashrc, etc.), but your terminal (alacritty).

Alacritty

In ~/.config/alacritty/alacritty.yml:

env:
  TERM: xterm-256color

tmux

In ~/.tmux.conf (or ~/.config/tmux/tmux.conf):

set -g default-terminal "tmux-256color"
set -ag terminal-overrides ",xterm-256color:RGB"

# Or use a wildcard instead of forcing a default mode.
# Some users in the comments of this gist have reported that this work better.
#set -sg terminal-overrides ",*:RGB"

# You can also use the env variable set from the terminal.
# Useful if you share your configuration betweeen systems with a varying value.
#set -ag terminal-overrides ",$TERM:RGB"

vim

In ~/.vimrc:

" You might have to force true color when using regular vim inside tmux as the
" colorscheme can appear to be grayscale with "termguicolors" option enabled.
if !has('gui_running') && &term =~ '^\%(screen\|tmux\)'
  let &t_8f = "\<Esc>[38;2;%lu;%lu;%lum"
  let &t_8b = "\<Esc>[48;2;%lu;%lu;%lum"
endif

syntax on
set termguicolors
colorscheme yourfavcolorscheme

neovim

If you use ~/.vimrc for your nvim configuration, use the above vim example because it's fully compatible.

💡 neovim recently (Dec 6th 2023) merged some changes that detects termguicolors automatically, so there's no need to set this in an upcoming release. I'll update this notice with a version once released as a public version. This came with the 0.10 release (May 16th 2024).

In ~/.config/nvim/init.vim

set termguicolors
colorscheme yourfavcolorscheme

Or ~/.config/nvim/init.lua:

vim.o.termguicolors = true
vim.cmd'colorscheme yourfavcolorscheme'

Not working correctly ?

Check out the comments below for possible solutions.

And if you found another solution I would really appreciate if you left a comment with instructions and the following information:

• OS/Distro + version
• Vim or Neovim + version
• Terminal name + version

Mentions

Shout-out to the nice folks that provided insightful feedback:

• @mikeslattery native neovim termguicolors support
• @mikeslattery black and white vim colorscheme
• @sahibalejandro env variable inside tmux configuration
• @wonbinbk wildcard in tmux terminal configuration

Thank you! TERM: xterm-256color was the last piece to the puzzle for me to get it to work properly!

Thanks g!

I'm using Lunar Vim + NeoVim and it's not working for Lunar.
If I open nvim it works, but not lvim.

I'm using Lunar Vim + NeoVim and it's not working for Lunar. If I open nvim it works, but not lvim.

same for me

@mjcc30 @orafaelfragoso LunarVim config is kept in a different directory. Read LunarVim's docs. You can't expect OP to support LunarVim, btw.

I had to set it to

set -g default-terminal "alacritty"
set -ag terminal-overrides ",alacritty:RGB"

OS: macos
Terminal: alacritty
Neovim

Thanks!

The only thing I needed to do was to add set -ag terminal-overrides ",alacritty:RGB" to my .tmux.conf file, nothing else.

macOS v12.3.1
NVIM v0.6.1
alacritty v0.10.1

@sahibalejandro I am guessing that works with Neovim but not Vim.

My experience with Neovim is that more things like this "just work"(tm). Personally, I'm sticking with the original config here as other true-color terminal apps I may install (if any) will be more likely to behave correctly.

Thank you! Life saver.

Thanks, Man, You saved my life…!!

Amazing! Thank you!

Thank You!

This is what worked for me:

alacritty.yml

env:
  TERM: xterm-256color

.tmux.conf

set -g default-terminal 'xterm-256color'
set -as terminal-overrides ',xterm*:Tc:sitm=\E[3m'

Thank you!

This was the only thing that worked for me too, arch linux

@nmdra May we get your .dotfiles ?
Thank you.

Thank you!!

Thank you!!

Thank you! 🍷

Thank you!

I recently discovered that you can use ENV variables inside your tmux.conf so you can have something like:

set -ag terminal-overrides ",$TERM:RGB"

This is useful in the case you're sharing (like me) your tmux.conf between computers and the value of $TERM is different for each one.

@sahibalejandro That's pretty sick! I've updated the document with this information :)

Hi guys, I was following the instruction and I hit another problem.
When I change

set -g default-terminal "screen-256color"

to

set -g default-terminal "tmux-256color"

The problem is exactly like this: https://stackoverflow.com/questions/45931164/duplicated-characters-and-non-updating-input-using-tmux-in-zsh
I don't know why :(

@phuongthuan I haven't personally experienced this, but I would suspect that it has something to do with your configuration files related to either the shell or tmux. If you have some custom stuff there, try to start fresh with these instructions and slowly start adding your other stuff.

Using

set -g default-terminal "tmux-256color"
set -ag terminal-overrides ",xterm-256color:RGB"

breaks tmux in alacritty with can't find terminal definition for tmux-256color error (as well as using tmux.conf without default-terminal and terminal-overrides declarations), but fonts and color in neovim are ok, but :checkhealth says

  - WARNING: Neither Tc nor RGB capability set. True colors are disabled. 'termguicolors' won't work properly.
    - ADVICE:
      - Put this in your ~/.tmux.conf and replace XXX by your $TERM outside of tmux:
          set-option -sa terminal-overrides ',XXX:RGB'
      - For older tmux versions use this instead:
          set-option -ga terminal-overrides ',XXX:Tc'

Using

set -g default-terminal "xterm-256color"

fixes opening tmux, neovim fonts are ok, but colors changed and :checkhealth says:

  - ERROR: $TERM should be "screen-256color" or "tmux-256color" in tmux. Colors might look wrong.
    - ADVICE:
      - Set default-terminal in ~/.tmux.conf:
          set-option -g default-terminal "screen-256color"
      - https://github.com/neovim/neovim/wiki/FAQ

Well, using

set -g default-terminal "screen-256color"
set -ag terminal-overrides ",xterm-256color:RGB"

fixes opening tmux, fixes neovim colors and :checkhealth, but breaks neovim fonts

What a mess!

UPD: After updating ncurses by this guide, tmux-256color is finally supported and all works good

Only thing that worked for me: adding set -ag terminal-overrides ",alacritty:RGB" to .tmux.conf file

macOS v12.4
NVIM v0.7.2
alacritty v0.10.1

Thanks so much!

I use iTerm2 and Alacritty at the same time, and the following settings work fine on my machine.

Versions

• macOS 13.0 Beta
• iTerm2 3.4.16
• alacritty 0.10.1
• tmux 3.3a
• NVIM 0.8.0-dev

Configurations

• iTerm2

  Preferences -> Profiles -> Terminal
  
  Terminal Emulation
    Report terminal type: xterm-256color
  

• Alacritty

  # ~/.config/alacritty/alacritty.yml
  env:
    TERM: xterm-256color

• Tmux

  # .tmux.conf
  set -g default-terminal "xterm-256color"
  set -ag terminal-overrides ",xterm-256color:RGB"

Tried all the things but nothing works

OS: Voidlinux
Alacritty: 0.10.1
Tmux: 3.3a

I followed all your instructions but still in tmux it couldn't display 24-bit color.
However, just by luck I found another guide and the only difference is in this:

set -ag terminal-overrides ",xterm-256color:RGB" -> set -sg terminal-overrides ",*:RGB"

And there we go, I have 24-bit color in tmux.

I followed all your instructions but still in tmux it couldn't display 24-bit color. However, just by luck I found another guide and the only difference is in this:

set -ag terminal-overrides ",xterm-256color:RGB" -> set -sg terminal-overrides ",*:RGB"

And there we go, I have 24-bit color in tmux.

Same here on arch linux with latest tmux and alacritty. I tried every suggestion in this thread but only after setting set -sg terminal-overrides ",*:RGB" and restarting the tmux server I had true 24b support.