Support running as greeter

data/io.elementary.desktop.wm.shell

@@ -1,7 +1,25 @@
 [io.elementary.wingpanel]
 launch-on-x=true
 args=io.elementary.wingpanel
+session-type=desktop
 
 [io.elementary.dock]
 launch-on-x=true
 args=io.elementary.dock
+session-type=desktop
+
+[Greeter wingpanel]
+args=io.elementary.wingpanel;-g
+session-type=greeter
+
+[Greeter Session Manager]
+args=io.elementary.greeter-session-manager
+session-type=greeter
+
+[Greeter]
+args=io.elementary.greeter
+session-type=greeter
+
+[Greeter Settings Daemon]
+args=io.elementary.settings-daemon
+session-type=greeter

lib/SessionSettings.vala

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2026 elementary, Inc. (https://elementary.io)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Authored by: Leonhard Kargl <leo.kargl@proton.me>
+ */
+
+namespace Gala.SessionSettings {
+    private enum SessionType {
+        DESKTOP,
+        GREETER,
+        INSTALLER;
+    }
+
+    private static SessionType? session_type = null;
+
+    private static SessionType get_session_type () {
+        if (session_type == null) {
+            var session_type_str = Environment.get_variable ("GALA_SESSION_TYPE") ?? "desktop";
+            switch (session_type_str) {
+                case "desktop":
+                    session_type = DESKTOP;
+                    break;
+                case "greeter":
+                    session_type = GREETER;
+                    break;
+                case "installer":
+                    session_type = INSTALLER;
+                    break;
+                default:
+                    warning ("Unknown session type: %s", session_type_str);
+                    session_type = DESKTOP;
+                    break;
+            }
+        }
+
+        return session_type;
+    }
+
+    public string get_shell_clients_type () {
+        switch (get_session_type ()) {
+            case DESKTOP:
+                return "desktop";
+            case GREETER:
+                return "greeter";
+            case INSTALLER:
+                return "installer";
+        }
+
+        return "desktop";
+    }
+
+    public bool should_set_xdg_current_desktop () {
+        return get_session_type () != DESKTOP;
+    }
+
+    public bool should_animate_panels () {
+        /* In the other types we fade in anyways */
+        return get_session_type () == DESKTOP;
+    }
+
+    public bool should_blur_background () {
+        return get_session_type () != DESKTOP;
+    }
+
+    public bool should_fade_in () {
+        return get_session_type () != DESKTOP;
+    }
+}

lib/meson.build

@@ -8,6 +8,7 @@ gala_lib_sources = files(
     'Constants.vala',
     'DragDropAction.vala',
     'Plugin.vala',
+    'SessionSettings.vala',
     'Utils.vala',
     'WindowManager.vala',
     'AppSystem/App.vala',

src/Background/BackgroundContainer.vala

@@ -54,6 +54,10 @@ public class Gala.BackgroundContainer : Meta.BackgroundGroup {
         for (var i = 0; i < display.get_n_monitors (); i++) {
             var background = new BackgroundManager (display, i);
 
+            if (SessionSettings.should_blur_background ()) {
+                background.add_effect (new BlurEffect (background, 18));
+            }
+
             add_child (background);
 
             if (i == 0)

src/Main.vala

@@ -27,6 +27,12 @@ namespace Gala {
     }
 
     public static int main (string[] args) {
+        if (SessionSettings.should_set_xdg_current_desktop ()) {
+            // Ensure we present ourselves as Pantheon so we pick up the right GSettings
+            // overrides
+            Environment.set_variable ("XDG_CURRENT_DESKTOP", "Pantheon", true);
+        }
+
         GLib.Intl.setlocale (LocaleCategory.ALL, "");
         GLib.Intl.bindtextdomain (Config.GETTEXT_PACKAGE, Config.LOCALEDIR);
         GLib.Intl.bind_textdomain_codeset (Config.GETTEXT_PACKAGE, "UTF-8");

src/ShellClients/ShellClientsManager.vala

@@ -101,6 +101,15 @@ public class Gala.ShellClientsManager : Object, GestureTarget {
                 }
             }
 
+            try {
+                var type = key_file.get_string (group, "session-type");
+                if (type != SessionSettings.get_shell_clients_type ()) {
+                    continue;
+                }
+            } catch (Error e) {
+                warning ("Failed to check session type for client %s, assuming it should be launched: %s", group, e.message);
+            }
+
             try {
                 var args = key_file.get_string_list (group, "args");
                 protocol_clients += new ManagedClient (wm.get_display (), args);
@@ -109,6 +118,11 @@ public class Gala.ShellClientsManager : Object, GestureTarget {
             }
         }
 
+        if (!SessionSettings.should_animate_panels ()) {
+            starting_panels = 0;
+            return;
+        }
+
         starting_panels = protocol_clients.length;
     }
 

src/WindowManager.vala

@@ -139,6 +139,10 @@ namespace Gala {
 
             show_stage ();
 
+            if (SessionSettings.should_fade_in ()) {
+                fade_in.begin ();
+            }
+
             init_a11y ();
 
             AccessDialog.watch_portal ();
@@ -418,6 +422,22 @@ namespace Gala {
             });
         }
 
+        private async void fade_in () {
+            var fade_in_actor = new Clutter.Actor () {
+                background_color = { 0, 0, 0, 255 },
+            };
+            fade_in_actor.add_constraint (new Clutter.BindConstraint (stage, SIZE, 0));
+            stage.add_child (fade_in_actor);
+
+            /* TODO: We might want to wait another second before we start the fade otherwise it's not really visible */
+
+            var transition_builder = new TransitionBuilder (fade_in_actor, 1000, EASE);
+            transition_builder.add_property ("opacity", 0u);
+            yield transition_builder.run ();
+
+            stage.remove_child (fade_in_actor);
+        }
+
         private void init_a11y () {
             if (!Clutter.get_accessibility_enabled ()) {
                 warning ("Clutter has no accessibility enabled");