True colour (24 bit) with Neovim, tmux and iTerm2

Neovim recently added 24 bit true colour support so I thought I’d get the rest of my environment setup with true colour. First thing is to download and intall the latest nightly build of iTerm2.

Next let’s install the latest version of Neovim:

brew tap neovim/homebrew-neovim
brew install --HEAD neovim

If you’ve already installed it:

brew reinstall neovim

Next for convenience I’ve updated my aliases for starting up vim to set the environment variable required to enable true colour in Neovim:

# .zshrc
alias v='NVIM_TUI_ENABLE_TRUE_COLOR=1 nvim'
alias vim='NVIM_TUI_ENABLE_TRUE_COLOR=1 nvim'

I also symlink my .vimrc to .nvimrc for convenience:

ln -nfs ~/.vimrc ~/.nvimrc

If you were using 256 colours with vim before, say with the base16 colour schemes, you’ll want to remove the 256 colour space setting:

" .nvimrc
" let base16colorspace=256

Starting Neovim now should give you true colours. Here’s a screenshot of Macvim and Neovim side by side:

Last thing is to install a patched version of tmux that has true colour support. Christian Hopps has a repository of homebrew recipes with patched versions of tmux, vim and emacs. Let’s install tmux from his repo:

brew uninstall tmux
brew install https://raw.githubusercontent.com/choppsv1/homebrew-term24/master/tmux.rb

Now make sure to exit all existing tmux sessions and you should have true colour support.

Last thing I’ve noticed is git doesn’t seem to pickup the aliases and launches regular vim. Add the following to your ~/.gitconfig under [core] to make sure nvim gets launched for commit messages:

editor = "NVIM_TUI_ENABLE_TRUE_COLOR=1 nvim"