locatePointer: Add implementation in gnome-shell

The "locate pointer" functionality was implemented in gnome settings
daemon using X11 protocols and would fail when run under Wayland.

With Wayland, there is no global coordinate space exposed to the clients
so this functionality cannot be implemented as a separate program.

Instead, add the "locate pointer" functionality in gnome-shell so that
it works in both X11 and Wayland.

https://gitlab.gnome.org/GNOME/gnome-shell/issues/981
https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/413
https://gitlab.gnome.org/GNOME/mutter/merge_requests/453
https://gitlab.gnome.org/GNOME/gsettings-desktop-schemas/merge_requests/19
https://gitlab.gnome.org/GNOME/gnome-settings-daemon/merge_requests/86

js/js-resources.gresource.xml

@@ -64,6 +64,7 @@
     <file>ui/keyboard.js</file>
     <file>ui/layout.js</file>
     <file>ui/lightbox.js</file>
+    <file>ui/locatePointer.js</file>
     <file>ui/lookingGlass.js</file>
     <file>ui/magnifier.js</file>
     <file>ui/magnifierDBus.js</file>

js/ui/locatePointer.js

@@ -0,0 +1,24 @@
+// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+
+const { Clutter, Gio, GLib, St } = imports.gi;
+const Ripples = imports.ui.ripples;
+const Main = imports.ui.main;
+
+const LOCATE_POINTER_KEY = "locate-pointer";
+const LOCATE_POINTER_SCHEMA = "org.gnome.desktop.interface"
+
+var locatePointer = class {
+    constructor() {
+        this._settings = new Gio.Settings({schema_id: LOCATE_POINTER_SCHEMA});
+        this._ripples = new Ripples.Ripples(0.5, 0.5, 'ripple-pointer-location');
+        this._ripples.addTo(Main.uiGroup);
+    }
+
+    show() {
+        if (!this._settings.get_boolean("locate-pointer"))
+            return;
+
+        let [x, y, mods] = global.get_pointer();
+        this._ripples.playAnimation(x, y);
+    }
+};

js/ui/main.js

@@ -37,6 +37,7 @@ const WindowManager = imports.ui.windowManager;
 const Magnifier = imports.ui.magnifier;
 const XdndHandler = imports.ui.xdndHandler;
 const KbdA11yDialog = imports.ui.kbdA11yDialog;
+const LocatePointer = imports.ui.locatePointer;
 
 const A11Y_SCHEMA = 'org.gnome.desktop.a11y.keyboard';
 const STICKY_KEYS_ENABLE = 'stickykeys-enable';
@@ -74,6 +75,7 @@ var layoutManager = null;
 var kbdA11yDialog = null;
 var inputMethod = null;
 var introspectService = null;
+var locatePointer = null;
 let _startDate;
 let _defaultCssStylesheet = null;
 let _cssStylesheet = null;
@@ -92,6 +94,8 @@ function _sessionUpdated() {
     wm.allowKeybinding('overlay-key', Shell.ActionMode.NORMAL |
                                       Shell.ActionMode.OVERVIEW);
 
+    wm.allowKeybinding('locate-pointer-key', Shell.ActionMode.ALL);
+
     wm.setCustomKeybindingHandler('panel-run-dialog',
                                   Shell.ActionMode.NORMAL |
                                   Shell.ActionMode.OVERVIEW,
@@ -165,6 +169,8 @@ function _initializeUI() {
     kbdA11yDialog = new KbdA11yDialog.KbdA11yDialog();
     wm = new WindowManager.WindowManager();
     magnifier = new Magnifier.Magnifier();
+    locatePointer = new LocatePointer.locatePointer();
+
     if (LoginManager.canLock())
         screenShield = new ScreenShield.ScreenShield();
 
@@ -190,6 +196,10 @@ function _initializeUI() {
             overview.toggle();
     });
 
+    global.connect('locate-pointer', () => {
+        locatePointer.show();
+    });
+
     global.display.connect('show-restart-message', (display, message) => {
         showRestartMessage(message);
         return true;