Use GTK for the WindowSwitcher

data/gala.gschema.xml

@@ -271,4 +271,23 @@
       <description></description>
     </key>
   </schema>
+
+  <schema path="/io/elementary/desktop/window-switcher/" id="io.elementary.desktop.window-switcher">
+    <key type="as" name="switch-windows">
+      <default><![CDATA[['<Alt>Tab']]]></default>
+      <summary>Switch between windows.</summary>
+    </key>
+    <key type="as" name="switch-windows-backward">
+      <default><![CDATA[['<Alt><Shift>Tab']]]></default>
+      <summary>Switch between windows backwards.</summary>
+    </key>
+    <key type="as" name="switch-group">
+      <default><![CDATA[['<Alt>grave']]]></default>
+      <summary>Switch between windows of the current application.</summary>
+    </key>
+    <key type="as" name="switch-group-backward">
+      <default><![CDATA[['<Alt><Shift>grave']]]></default>
+      <summary>Switch between windows of the current application backwards.</summary>
+    </key>
+  </schema>
 </schemalist>

lib/Plugin.vala

@@ -18,7 +18,6 @@
 namespace Gala {
     public enum PluginFunction {
         ADDITION,
-        WINDOW_SWITCHER,
         WORKSPACE_VIEW,
         WINDOW_OVERVIEW
     }

meson.build

@@ -189,6 +189,7 @@ if get_option('documentation')
     subdir('docs')
 endif
 subdir('po')
+subdir('windowSwitcher')
 
 vapigen = find_program('vapigen', required: false)
 if vapigen.found()

src/DBus.vala

@@ -30,6 +30,15 @@ public class Gala.DBus {
             () => {},
             () => warning ("Could not acquire name\n") );
 
+        Bus.own_name (BusType.SESSION, "io.elementary.desktop.wm", BusNameOwnerFlags.NONE,
+            (connection) => {
+                try {
+                    connection.register_object ("/io/elementary/desktop/wm", new DBusGestureProvider ());
+                } catch (Error e) { warning (e.message); }
+            },
+            () => {},
+            () => warning ("Could not acquire name") );
+
         Bus.own_name (BusType.SESSION, "org.gnome.Shell", BusNameOwnerFlags.NONE,
             (connection) => {
                 try {

src/Gestures/DBusGestureProvider.vala

@@ -0,0 +1,19 @@
+[DBus (name = "io.elementary.desktop.wm.GestureProvider")]
+public class Gala.DBusGestureProvider : Object {
+    public signal void on_gesture_detected (Gesture gesture);
+    public signal void on_begin (double percentage);
+    public signal void on_update (double percentage);
+    public signal void on_end (double percentage, bool cancel_action, int calculated_duration);
+
+    private GestureTracker gesture_tracker;
+
+    construct {
+        gesture_tracker = new GestureTracker (0, 0);
+        gesture_tracker.enable_touchpad ();
+
+        gesture_tracker.on_gesture_detected.connect ((gesture) => on_gesture_detected (gesture));
+        gesture_tracker.on_begin.connect ((percentage) => on_begin (percentage));
+        gesture_tracker.on_update.connect ((percentage) => on_update (percentage));
+        gesture_tracker.on_end.connect ((percentage, cancel_action, calculated_duration) => on_end (percentage, cancel_action, calculated_duration));
+    }
+}

src/Gestures/Gesture.vala

@@ -34,7 +34,7 @@ namespace Gala {
         OUT = 6,
     }
 
-    public class Gesture {
+    public struct Gesture {
         public Clutter.EventType type;
         public GestureDirection direction;
         public int fingers;

src/PluginManager.vala

@@ -36,7 +36,6 @@ namespace Gala {
             return _regions;
         }
 
-        public string? window_switcher_provider { get; private set; default = null; }
         public string? window_overview_provider { get; private set; default = null; }
         public string? workspace_view_provider { get; private set; default = null; }
 
@@ -155,13 +154,6 @@ namespace Gala {
                     }
                     window_overview_provider = name;
                     return true;
-                case PluginFunction.WINDOW_SWITCHER:
-                    if (window_switcher_provider != null) {
-                        warning (message, window_switcher_provider, name, "window switcher");
-                        return false;
-                    }
-                    window_switcher_provider = name;
-                    return true;
                 default:
                     break;
             }