Plymouth

Plymouth is an application that runs early in the boot process, providing a graphical boot animation, it is used by most desktop-oriented Linux distributions.

Usage

As an example, you can use a boot animation from adi1090x's collection like so:

❄︎ configuration.nix

{ pkgs, ... }: {
  boot = {

    plymouth = {
      enable = true;
      theme = "rings";
      themePackages = with pkgs; [
        # By default we would install all themes
        (adi1090x-plymouth-themes.override {
          selected_themes = [ "rings" ];
        })
      ];
    };

    # Enable "Silent boot"
    consoleLogLevel = 3;
    initrd.verbose = false;
    kernelParams = [
      "quiet"
      "splash"
      "boot.shell_on_fail"
      "udev.log_priority=3"
      "rd.systemd.show_status=auto"
    ];
    # Hide the OS choice for bootloaders.
    # It's still possible to open the bootloader list by pressing any key
    # It will just not appear on screen unless a key is pressed
    loader.timeout = 0;

  };
}

During the graphical boot process, it is possible to switch to text mode and back by pressing the escape key. If you are using LUKS encryption and the password prompt falls back to text mode, it may help to switch to initrd-systemd mode:

boot.initrd.systemd.enable = true;

While the default bgrt theme supports graphical password entry, this may not be supported by all themes.