neovim-dark-monitor

A libdarknotify based neovim plugin that allows to automatically change the editor theme whenever the OS theme is changed too.

Supported platforms

• Windows 10 or newer
• macOS
• Linux/FreeBSD/other platforms that support GLib and org.freedesktop.appearance.color-scheme
• WSL

Building instructions

Requirements

• C++20 supporting compiler
• meson build system
• Compile-time dependencies (optional, as they can be installed by the meson build system automatically):
  • range-v3
  • msgpack-cxx
  • tl-expected
• Run-time dependencies:
  • Boost
  • (Linux only) GLib (including GIO and GObject)

Compilation

git submodule update --init --recursive
meson wrap update-db
meson setup -Ddefault_library=static --buildtype=release bin
ninja -C bin

Usage

How does it work?

When connected to the v:servername, neovim-dark-monitor first registers DarkMonitorQuery Lua function, then invokes an OnDarkMonitorConnected autocommand. Then every time the OS theme is changed, the OnDarkMonitorThemeChange is invoked.

What do I need to do?

It is recommended to copy the resulting executable to ~/.config/nvim/rplugin/neovim-dark-monitor.exe (an .exe extension is needed to make a single config usable for Windows and other systems).

The example of the lua config file:

if os.getenv('XDG_SESSION_TYPE') == 'tty' then
    return
end

local dark_monitor_exe = vim.api.nvim_get_runtime_file('rplugin/neovim-dark-monitor.exe', false)
if next(dark_monitor_exe) == nil then
    return
end

local current_os = vim.loop.os_uname()
local rpc_socket = vim.v.servername

-- Currently Neovim on Windows spawns a named pipe instead of a regular socket on startup,
-- but `neovim-dark-monitor` doesn't support them.
--
-- This is a subject to change on the Neovim side, because Windows has added a support
-- for `AF_UNIX` sockets since 2018 (more info: https://github.com/neovim/neovim/issues/11363 ),
-- but currently we have to work this around by spawning an IP socket manually.
--
-- Under WSL we need to run the Win32 executable to make it actually work, but Win32 applications
-- cannot connect to the UNIX sockets that are spawned in the VM, so we also have to spawn an IP socket
local is_windows_pipes = current_os.sysname:find('Windows') and rpc_socket:find('\\\\.\\pipe') == 1
local is_wsl = current_os.release:find('WSL')
if is_windows_pipes or is_wsl then
    -- start listening on an arbitrary port
    rpc_socket = vim.fn.serverstart('127.0.0.1:0')
end

assert(#dark_monitor_exe == 1)
assert(type(rpc_socket) == 'string')
-- It is better to use `vim.system` on neovim version 0.10+
local job_id = vim.fn.jobstart({dark_monitor_exe[1], '--nvim-sock', rpc_socket}, {
    detach = true,
    stdin = nil
})
assert(job_id > 0, 'Unable to start the `neovim-dark-monitor` job')

local set_theme = function(theme)
    if theme == 'dark' then
        vim.o.background = 'dark'
        vim.cmd('colorscheme my_favorite_dark_theme')
    elseif theme == 'light' then
        vim.o.background = 'light'
        vim.cmd('colorscheme my_favorite_light_theme')
    else
        vim.print(string.format('neovim-dark-monitor: Theme is unknown (%s)', tostring(theme)))
    end
end

local dark_monitor_group = vim.api.nvim_create_augroup('DarkMonitorConfig', { clear = true })
vim.api.nvim_create_autocmd('User', {
    group = dark_monitor_group,
    pattern = 'OnDarkMonitorConnected',
    callback = function(ev)
        set_theme(DarkMonitorQuery())
    end
})
vim.api.nvim_create_autocmd('User', {
    group = dark_monitor_group,
    pattern = 'OnDarkMonitorThemeChange',
    callback = function(ev)
        local theme = ev.data
        set_theme(theme)
    end
})

Comparing neovim-dark-monitor to other implementations

vim-lumen

Its pros:

• No need to build anything
• Works with both vim and neovim

Its cons:

• For each new vim instance it spawns another process which monitors the system theme, whereas neovim-dark-monitor can control all the instances within a single process
• It doesn't provide an ability to query current theme at any time
• It is written in vimscript, so it should be a bit slower (but you probably won't notice that anyway though)

auto-dark-mode.nvim

Its pros:

• No need to build anything

Its cons:

• Spawns a new process each N seconds to query the current theme

dark-notify

Its cons:

• Strange Lua API
• Works only on macOS
• Parses stdin internally, which is slow and bodgy
• rustc doesn't come by default on many systems