Xfce
Xfce is a lightweight desktop environment based on GTK+. It includes a window manager, a file manager, desktop and panel.
This article is an extension of the documentation in the NixOS manual.
Enabling
To use xfce set services.xserver.desktopManager.xfce.enable to true. For example:
{ config, pkgs, callPackage, ... }: {
...
# if you use pulseaudio
nixpkgs.config.pulseaudio = true;
services.xserver = {
enable = true;
desktopManager = {
xterm.enable = false;
xfce.enable = true;
};
};
services.displayManager.defaultSession = "xfce";
...
}
$ nixos-rebuild switch --sudo
Excluding xfce applications
Xfce does not include as many applications by default as some other desktop environments. Still, those can be excluded as demonstrated in the example below. Place this before the services.xserver snippet from above.
{
environment.xfce.excludePackages = with pkgs.xfce; [
mousepad
parole
# ristretto
xfce4-appfinder
# xfce4-notifyd
xfce4-screenshooter
# xfce4-session
# xfce4-settings
# xfce4-taskmanager
# xfce4-terminal
];
}
Using as a desktop manager and not a window manager
You can use xfce purely as a desktop manager, leaving window management to another window manager like i3 for example. In this scenario, xfce's role is to answer to media keys, prompt when plugging a new monitor and so on.
Example config:
{ config, pkgs, callPackage, ... }: {
...
services.xserver = {
enable = true;
desktopManager = {
xterm.enable = false;
xfce = {
enable = true;
noDesktop = true;
enableXfwm = false;
};
};
windowManager.i3.enable = true;
};
services.displayManager.defaultSession = "xfce";
...
}
$ nixos-rebuild switch --sudo
On first login, make sure to choose the session xfce+i3 in your display manager.
If you choose xfce you will end up in xfce without panels nor window manager, which
is unusable.
Note that xfce manages your session instead of i3: exiting i3 will blank your screen but not terminate your session.
In your i3 config, replace i3-msg exit with xfce4-session-logout.
With xmonad as the window manager
One of the possibilities is to use xmonad as a window manager in a Xfce desktop environment.
Without xfce desktop
The previously described configuration is extended with the part that configures xmonad:
{ config, pkgs, callPackage, ... }: {
...
services.xserver = {
enable = true;
desktopManager = {
xterm.enable = false;
xfce = {
enable = true;
noDesktop = true;
enableXfwm = false;
};
};
windowManager = {
xmonad = {
enable = true;
enableContribAndExtras = true;
extraPackages = haskellPackages : [
haskellPackages.xmonad-contrib
haskellPackages.xmonad-extras
haskellPackages.xmonad
];
};
};
};
services.displayManager.defaultSession = "xfce+xmonad";
...
}
Xmonad's contrib package comes with a config to integrate seamlessly into Xfce, like connecting workspaces to xfce's top panel's preview of workspaces. To enable this config, put the following into the user's xmonad config file:
import XMonad
import XMonad.Config.Xfce
main = xmonad xfceConfig
{ terminal = "xfce4-terminal"
, modMask = mod4Mask -- optional: use Win key instead of Alt as MODi key
}
Since Xfce uses Alt for a lot of keybindings, using the Win key for xmonad hotkeys may be preferred.
$ nixos-rebuild switch --sudo
After choosing the xfce+xmonad session in your display manager, you will be taken to a clean screen, where you can open a terminal with MOD+Shift+Enter or launch an application with MOD(+SHIFT)+p.
With xfce desktop
If you instead prefer to have panels (like the top panel) in addition to the main clean display area managed by xmonad, you can remove the xfce.noDesktop = true; option from the configuration.
$ nixos-rebuild switch --sudo
After switching to your new configuration, reboot and clean your sessions with rm -rf ~/.cache/sessions/* before logging in to a graphical session.
After logging in you will be greeted by xfce's desktop which interferes with xmonad. To solve this issue you have to remove the xfdesktop process from being started in the session.
Open the session manager in the application launcher with MOD(+SHIFT)+p and then typing in "Session and Startup". Go to tab "Session" and set the restart style of xfdesktop to "Never". Kill the process with "Quit program", then "Save session." After this, xfce4 and xmonad will work together nicely.
Java-based GUI applications
Java-based applications may not work properly with xmonad. The applications main window may stay blank or gray on startup. This is a known issue with some versions of Java, where xmonad is not recognized as a "non-reparenting" window manager. There are multiple solutions to this problem as described on xmonad's FAQ page.
One alternative is to fake xmonad's window manager name, after running the EMWH initialization. This particular approach works well when running xmonad alongside the xfce-based desktop (described above).
import XMonad
import XMonad.Config.Xfce
import XMonad.Hooks.EwmhDesktops
import XMonad.Hooks.SetWMName
main = xmonad xfceConfig
{ terminal = "xfce4-terminal"
, modMask = mod4Mask -- Use Win as MOD key
, startupHook = ewmhDesktopsStartup >> setWMName "LG3D" -- for some reason the double greater sign is escaped here due to wiki formatting, replace this with proper greater signs!
}
Additional resources
Note that, unlike suggested in additional resources, the xmonad packages should not be installed in the environment (neither as systemPackages nor user packages), since that leads to errors when (re)compiling xmonad's config file.
Additional resources:
Haskell Wiki: Installing xmonad on NixOS
Haskell Wiki: Using xmonad in Xfce
Customizing xfce declaratively
Xfce adheres to XDG desktop configuration, making it easy to declare user home directory configurations via Home Manager. xfce-specific configurations are stored in an xfconf database.
Defining xfconf value
Below assumes you have already enabled Home Manager in your NixOS configuration.
Launching xfce4-settings-editor you can view xfce personalizations already applied to the system. They're displayed in a tree view, but stored in a flat string format. You can query these same values from the command line with xfconf-query to quickly get the full key and value in a friendlier format. For instance:
$ xfconf-query -c ristretto -lv
/window/navigationbar/position left
/window/statusbar/show true
/window/toolbar/show falseCan be translated like so:
# Xfce Home Manager customizations
home-manager.users.${PRIMARY-USER} = { config, ... }: ({
xfconf = {
enable = true;
settings = {
ristretto = {
"window/navigationbar/position" = "left";
"window/statusbar/show" = true;
"window/toolbar/show" = false;
};
};
};
})
Using built-in wallpapers
Similarly, if you wish to use a built-in wallpaper declaratively you could follow this same pattern:
# Values based on `xfconf-query -c xfce4-desktop -lv`
home-manager.users.${PRIMARY-USER} = { config, ... }: ({
xfconf = {
enable = true;
settings = {
xfce4-desktop = {
"backdrop/screen0/monitor0/workspace0/color-style" = 0;
"backdrop/screen0/monitor0/workspace0/image-style" = 5;
"backdrop/screen0/monitor0/workspace0/last-image" = "${pkgs.xfce.xfdesktop}/share/backgrounds/xfce/xfce-cp-dark.svg";
};
};
};
})
However, the xfce settings seem to persist across system rebuilds which can lead to the wallpaper being set to a nix store that is cleaned up when older system generations are cleaned up. In other words, the wallpaper may be replaced by a blank screen upon reboot seemingly randomly. One workaround for this is to set a static directory path for the images via a symlink and using that within xfconf.
# ".xfce-wallpaper" directory is created below so that xfce's
# settings aren't pointed to a dynamic, moving nix store path
let background-dir = "/home/${PRIMARY-USER}/.xfce4-wallpapers";
background-image = "${background-dir}/xfce-cp-dark.svg";
in {
home-manager.users.${PRIMARY-USER} = { config, ... }: ({
home.file.".xfce4-wallpapers".source = config.lib.file.mkOutOfStoreSymlink "${pkgs.xfce.xfdesktop}/share/backgrounds/xfce";
xfconf = {
enable = true;
settings = {
xfce4-desktop = {
"backdrop/screen0/monitor0/workspace0/color-style" = 0;
"backdrop/screen0/monitor0/workspace0/image-style" = 5;
"backdrop/screen0/monitor0/workspace0/last-image" = background-image;
};
};
};
})
Troubleshooting
Pulseaudio
If you use pulse audio, set nixpkgs.config.pulseaudio = true as shown above. Otherwise, you may
experience glitches like being able to mute the sound card but not unmute it.