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! 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.

If you have nvim installed, you can open it and type the command :checkhealth and it will give some debugging tips for tmux colors as well

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"

Thanks! It works for me.

Thank you so much, finally it worked 🎉

This line from the comments helped also set -sg terminal-overrides ",*:RGB"

@wonbinbk I've added your solution to this document as it seems other users have success in using this as well.

Haven't been able to reproduce the issues with original instructions even on the same systems as reported, but it seems like this area is filled with dragons 😅

Thanks!

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!

• OS: [email protected] (Monterey, M1)

Almost worked perfectly but the terminal override inappropriately rendered \E[3m characters in Neovim, so I ended up fiddling and tweaking using these guides until colours, symbols, bold, italics all worked for me:

• https://gist.github.com/andersevenrud/015e61af2fd264371032763d4ed965b6
• https://gist.github.com/joshuarli/247018f8617e6715e1e0b5fd2d39bb6c
• alacritty/alacritty#109

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 worked for me as well, thanks!

- macOS Monterey @ 12.6.1
- Alacritty      @ 0.11.0
- 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.

Thanks for that solution!
I'm using pop os with alacritty neovim and tmux, but when I installed tmux, my colors on neovim broken. After put set -sg terminal-overrides ",*:RGB" everything works again.

ssh does not work correctly for one of my other desktops, probably because tmux-256color is unknown to it. I had to SetEnv to my ~/.ssh/config. There might be a better way, but this works well.

Host otherdesktop
  Hostname otherdesktop
  SetEnv TERM=xterm

Ad-hoc alternate: TERM=xterm ssh otherdesktop

Works like charm. Thank you so much