Navigation Menu

Skip to content

Instantly share code, notes, and snippets.

@andersevenrud
Last active April 22, 2024 15:59
Show Gist options
  • Save andersevenrud/015e61af2fd264371032763d4ed965b6 to your computer and use it in GitHub Desktop.
Save andersevenrud/015e61af2fd264371032763d4ed965b6 to your computer and use it in GitHub Desktop.
True Color (24-bit) and italics with alacritty + tmux + vim (neovim)

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

colors

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.

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:

@nickgnd
Copy link

nickgnd commented Oct 24, 2023

Hey 👋
This combination of settings works fine for me

# .alacritty.yml

env:
  TERM: alacritty

and in my tmux config:

# tmux.conf

set-option -g default-terminal "screen-256color"
  • OS/Distro: MacOS Ventura 13.6
  • Vim: VIM - Vi IMproved 9.0
  • Terminal: alacritty 0.12.3 (5efb069)
  • Tmux: tmux 3.3a

Hope it can help ✌️

@antonkesy
Copy link

Alacritty versions >= 0.13.0 (moved to TOML for config)

[env]
TERM="xterm-256color"

@Hritik14
Copy link

Hritik14 commented Nov 7, 2023

Italics in my vim were messed up, if someone has this problem, you can verify by running

echo -e "\e[3mitalic\e[0m"

if output is in italics then it's a vim problem, otherwise something else is wrong.

I had to add the following in my vimrc as per this for italics.

let &t_ZH="\e[3m"
let &t_ZR="\e[23m"

using macvim, tmux and iterm2

@PThorpe92
Copy link

Thank you so much for this..

I legit switched to kitty for months over this issue, I had tried every fix out there (what did it was the ENV) so glad to be back with alacritty

@jonnovaretti
Copy link

AMAZING!!! Thanks

@mikeslattery
Copy link

mikeslattery commented Dec 11, 2023

BREAKING NEWS!

(edits: I was wrong. Only the neovim changes aren't necessary.)

tl;dr - This gist is no longer necessary with latest Neovim.

Neovim now checks for 256 color compatibility and automatically sets termguicolors. Alacritty with default $TERM value ("alacritty") works fine. I just tested it with nightly.

Recent changes announced at the Neovim conference a few days ago have made the changes in this gist unnecessary for latest builds. However, I'm sure as of this moment many people are using versions that don't yet support this and that will likely be the case for a few weeks. I don't know the exact version this was added, or which versions have it other than latest nightly.

Of course, it will still be necessary for Vim.

@andersevenrud
Copy link
Author

Thanks for the heads-up @mikeslattery ! This is great news :)

I'll update this article and follow up when this goes into a public release.

@mikeslattery
Copy link

mikeslattery commented Dec 13, 2023

Looks like I wasn't correct. You still need the tmux and alacritty config. You just don't need the neovim config anymore.

Quick test for Linux. As of this comment it works for nightly and not for release.

#!/bin/bash
# Test for truecolor.  Should see bands of smooth gradient colors.

# To test  installed nvim, set this to "nvim" and comment out #linux nvim install block, and remove rm $NVIM line
NVIM=/tmp/nvim

# Linux nvim install
NIGHTLY=https://github.com/neovim/neovim/releases/download/nightly/nvim.appimage
RELEASE=https://github.com/neovim/neovim/releases/download/stable/nvim.appimage
# Change to $NIGHTLY to see it working correctly.
curl -Lo $NVIM $RELEASE
chmod +x $NVIM

# Reconfigure
echo '
set -ag terminal-overrides ",xterm-256color:RGB"
' > /tmp/.tmux.conf
echo '
env:
  TERM: xterm-256color
' > /tmp/alacritty.yaml

# Test
TEST=https://gist.githubusercontent.com/lifepillar/09a44b8cf0f9397465614e622979107f/raw/24-bit-color.sh
alacritty --config-file /tmp/alacritty.yaml \
  -e tmux -f /tmp/.tmux.conf -L nvim new-session \
  $NVIM --clean  "+terminal curl -s $TEST | bash" "+set termguicolors?"
# old way:
# $NVIM --clean  +"set termguicolors" "+colorscheme ron" "+terminal curl -s $TEST | bash"

# Cleanup
rm "$NVIM"
rm /tmp/.tmux.conf /tmp/alacritty.yaml

@andersevenrud
Copy link
Author

Appreciate the detailed follow-up on this @mikeslattery. I've updated the article to reflect this 👍

@n0099
Copy link

n0099 commented Feb 29, 2024

echo 'set -as terminal-overrides ",'"$(echo ${TERM%%-*})"'*:Tc"' >> ~/.tmux.conf

https://github.com/tmux/tmux/wiki/FAQ#how-do-i-use-rgb-colour

tmux must be told that the terminal outside supports RGB colour. This is done by specifying the RGB or Tc terminfo(5) flags. RGB is the official flag, Tc is a tmux extension.

With tmux 3.2 and later this can be added with the terminal-features option:

set -as terminal-features ",gnome*:RGB"

Or for any tmux version the terminal-overrides option:

set -as terminal-overrides ",gnome*:Tc"

and replace gnome with the result of echo ${TERM%%-*} (the first part of $TERM delimited by -) from the terminal emulator that you are currently using outside tmux such as putty or xterm.

@ferBV
Copy link

ferBV commented Mar 24, 2024

Just what I needed, thank you a lot.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment