Implement maximize gesture

lib/Gestures/Gesture.vala

@@ -40,6 +40,7 @@ namespace Gala {
         SWITCH_WINDOWS,
         MULTITASKING_VIEW,
         ZOOM,
+        TOGGLE_MAXIMIZED,
         CUSTOM,
         N_ACTIONS;
 

lib/Gestures/GestureSettings.vala

@@ -72,6 +72,11 @@ private class Gala.GestureSettings : Object {
                         fingers == 4 && four_finger_swipe_up == "multitasking-view") {
                         return MULTITASKING_VIEW;
                     }
+
+                    if (fingers == 3 && three_finger_swipe_up == "toggle-maximized" ||
+                        fingers == 4 && four_finger_swipe_up == "toggle-maximized") {
+                        return TOGGLE_MAXIMIZED;
+                    }
                 }
                 break;
 

lib/Gestures/TouchpadBackend.vala

@@ -74,6 +74,14 @@ private class Gala.TouchpadBackend : Object, GestureBackend {
         event.get_gesture_motion_delta_unaccelerated (out delta_x, out delta_y);
 
         if (state != ONGOING) {
+            foreach (var instance in instances) {
+                if (instance != this && (instance.group == NONE || instance.group != group) && instance.state == ONGOING) {
+                    /* Another instance is already recognizing this gesture, make sure we don't steal it */
+                    state = IGNORED;
+                    return Clutter.EVENT_PROPAGATE;
+                }
+            }
+
             distance_x += delta_x;
             distance_y += delta_y;
 

src/Widgets/WindowMaximizer.vala

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2026 elementary, Inc. (https://elementary.io)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Authored by: Leonhard Kargl <leo.kargl@proton.me>
+ */
+
+public class Gala.WindowMaximizer : ActorTarget, RootTarget {
+    public WindowManager wm { get; construct; }
+
+    public Clutter.Actor? actor { get { return tile; } }
+
+    private Clutter.Actor tile;
+    private GestureController controller;
+
+    private Meta.Window? current_window;
+
+    public WindowMaximizer (WindowManager wm) {
+        Object (wm: wm);
+    }
+
+    construct {
+        tile = new Clutter.Actor () {
+            opacity = 200
+        };
+        Drawing.StyleManager.get_instance ().bind_property ("theme-accent-color", tile, "background-color", SYNC_CREATE);
+
+        add_child (tile);
+
+        controller = new GestureController (TOGGLE_MAXIMIZED);
+        controller.add_trigger (new GlobalTrigger (TOGGLE_MAXIMIZED, wm));
+        add_gesture_controller (controller);
+
+    }
+
+    public override void start_progress (GestureAction action) requires (action == TOGGLE_MAXIMIZED) {
+        current_window = wm.get_display ().focus_window;
+
+        if (current_window == null) {
+            return;
+        }
+
+        visible = true;
+        controller.progress = (double) current_window.maximized_horizontally;
+
+        var workarea = wm.get_display ().get_workspace_manager ().get_active_workspace ().get_work_area_for_monitor (current_window.get_monitor ());
+        var initial_rect = get_initial_rect (workarea);
+
+        add_target (new PropertyTarget (TOGGLE_MAXIMIZED, tile, "x", typeof (float), (float) initial_rect.x, (float) workarea.x));
+        add_target (new PropertyTarget (TOGGLE_MAXIMIZED, tile, "y", typeof (float), (float) initial_rect.y, (float) workarea.y));
+        add_target (new PropertyTarget (TOGGLE_MAXIMIZED, tile, "width", typeof (float), (float) initial_rect.width, (float) workarea.width));
+        add_target (new PropertyTarget (TOGGLE_MAXIMIZED, tile, "height", typeof (float), (float) initial_rect.height, (float) workarea.height));
+
+        var window_actor = (Meta.WindowActor) current_window.get_compositor_private ();
+        wm.window_group.set_child_above_sibling (this, window_actor);
+    }
+
+    private Mtk.Rectangle get_initial_rect (Mtk.Rectangle workarea) requires (current_window != null) {
+        if (!current_window.maximized_horizontally) {
+            return current_window.get_frame_rect ();
+        }
+
+        var unmaximized_geometry = WindowListener.get_default ().get_unmaximized_state_geometry (current_window);
+        if (unmaximized_geometry != null) {
+            return unmaximized_geometry.inner;
+        }
+
+        return { workarea.x + (workarea.width / 2), workarea.y + (workarea.height / 2), 0, 0 };
+    }
+
+    public override void commit_progress (GestureAction action, double commit) requires (action == TOGGLE_MAXIMIZED) {
+        if (current_window == null) {
+            return;
+        }
+
+        if (commit == 0 && current_window.maximized_horizontally) {
+#if HAS_MUTTER49
+            current_window.unmaximize ();
+#else
+            current_window.unmaximize (BOTH);
+#endif
+        } else if (commit == 1 && !current_window.maximized_horizontally) {
+#if HAS_MUTTER49
+            current_window.maximize ();
+#else
+            current_window.maximize (BOTH);
+#endif
+        }
+
+        remove_all_targets ();
+        visible = false;
+        current_window = null;
+    }
+}

src/WindowManager.vala

@@ -260,6 +260,7 @@ namespace Gala {
             background_group = new BackgroundContainer (display);
             ((BackgroundContainer)background_group).show_background_menu.connect (daemon_manager.show_background_menu);
             window_group.add_child (background_group);
+            window_group.add_child (new WindowMaximizer (this));
             window_group.set_child_below_sibling (background_group, null);
 
 #if HAS_MUTTER48

src/meson.build

@@ -66,6 +66,7 @@ gala_bin_sources = files(
     'Widgets/PointerLocator.vala',
     'Widgets/SessionLocker.vala',
     'Widgets/SelectionArea.vala',
+    'Widgets/WindowMaximizer.vala',
     'Widgets/WindowOverview.vala',
     'Widgets/WindowSwitcher/WindowSwitcher.vala',
     'Widgets/WindowSwitcher/WindowSwitcherIcon.vala',