backends: Add a method for monitoring cursor position

src/backends/meta-backend-private.h

@@ -95,6 +95,8 @@ struct _MetaBackendClass
   void (* set_numlock) (MetaBackend *backend,
                         gboolean     numlock_state);
 
+  void (* track_position) (MetaBackend *backend,
+                           gboolean     enabled);
 };
 
 void meta_init_backend (GType backend_gtype);
@@ -152,4 +154,8 @@ MetaInputSettings *meta_backend_get_input_settings (MetaBackend *backend);
 
 void meta_backend_update_cursor_position (MetaBackend *backend, int x, int y);
 
+void meta_backend_cursor_position_changed (MetaBackend *backend);
+void meta_backend_track_position_ref (MetaBackend *backend);
+void meta_backend_track_position_unref (MetaBackend *backend);
+
 #endif /* META_BACKEND_PRIVATE_H */

src/backends/meta-backend.c

@@ -78,6 +78,8 @@ struct _MetaBackendPrivate
   int current_device_id;
 
   MetaPointerConstraint *client_pointer_constraint;
+
+  uint32_t track_position_refcount;
 };
 typedef struct _MetaBackendPrivate MetaBackendPrivate;
 
@@ -866,3 +868,42 @@ meta_backend_get_input_settings (MetaBackend *backend)
 
   return priv->input_settings;
 }
+
+void
+meta_backend_update_cursor_position (MetaBackend *backend, int x, int y)
+{
+  MetaBackendPrivate *priv = meta_backend_get_instance_private (backend);
+
+  meta_cursor_renderer_set_position (priv->cursor_renderer, x, y);
+
+  meta_backend_cursor_position_changed (backend);
+}
+
+void
+meta_backend_cursor_position_changed (MetaBackend *backend)
+{
+  meta_cursor_tracker_cursor_position_changed (backend->cursor_tracker);
+}
+
+static void
+meta_backend_track_position (MetaBackend *backend, gboolean enabled)
+{
+  if (META_BACKEND_GET_CLASS (backend)->track_position)
+    META_BACKEND_GET_CLASS (backend)->track_position (backend, enabled);
+}
+
+void
+meta_backend_track_position_ref (MetaBackend *backend)
+{
+  MetaBackendPrivate *priv = meta_backend_get_instance_private (backend);
+  if (priv->track_position_refcount++ == 0)
+    meta_backend_track_position (backend, TRUE);
+}
+
+void
+meta_backend_track_position_unref (MetaBackend *backend)
+{
+  MetaBackendPrivate *priv = meta_backend_get_instance_private (backend);
+  if (priv->track_position_refcount-- == 0)
+    meta_backend_track_position (backend, FALSE);
+}

src/backends/meta-cursor-tracker-private.h

@@ -63,4 +63,6 @@ void     meta_cursor_tracker_set_root_cursor     (MetaCursorTracker *tracker,
 
 MetaCursorSprite * meta_cursor_tracker_get_displayed_cursor (MetaCursorTracker *tracker);
 
+void meta_backend_cursor_position_changed (MetaCursorTracker *tracker);
+
 #endif

src/backends/meta-cursor-tracker.c

@@ -47,6 +47,7 @@
 G_DEFINE_TYPE (MetaCursorTracker, meta_cursor_tracker, G_TYPE_OBJECT);
 
 enum {
+  POSITION_CHANGED,
   CURSOR_CHANGED,
   LAST_SIGNAL
 };
@@ -128,6 +129,13 @@ meta_cursor_tracker_class_init (MetaCursorTrackerClass *klass)
                                           0,
                                           NULL, NULL, NULL,
                                           G_TYPE_NONE, 0);
+
+  signals[POSITION_CHANGED] = g_signal_new ("position-changed",
+                                            G_TYPE_FROM_CLASS (klass),
+                                            G_SIGNAL_RUN_LAST,
+                                            0,
+                                            NULL, NULL, NULL,
+                                            G_TYPE_NONE, 0);
 }
 
 /**
@@ -421,3 +429,21 @@ meta_cursor_tracker_get_displayed_cursor (MetaCursorTracker *tracker)
 {
   return tracker->displayed_cursor;
 }
+
+void
+meta_cursor_tracker_position_changed (MetaCursorTracker *tracker)
+{
+  g_signal_emit (tracker, signals[POSITION_CHANGED], 0);
+}
+
+void
+meta_cursor_tracker_enable_track_position (MetaCursorTracker *tracker)
+{
+  meta_backend_track_position_ref (meta_get_backend ());
+}
+
+void
+meta_cursor_tracker_disable_track_position (MetaCursorTracker *tracker)
+{
+  meta_backend_track_position_unref (meta_get_backend ());
+}

src/backends/x11/cm/meta-backend-x11-cm.c

@@ -114,7 +114,8 @@ meta_backend_x11_cm_update_screen_size (MetaBackend *backend,
 }
 
 static void
-meta_backend_x11_cm_select_stage_events (MetaBackend *backend)
+select_xi_stage (MetaBackend *backend,
+                 gboolean     include_motion)
 {
   MetaBackendX11 *x11 = META_BACKEND_X11 (backend);
   Display *xdisplay = meta_backend_x11_get_xdisplay (x11);
@@ -132,9 +133,24 @@ meta_backend_x11_cm_select_stage_events (MetaBackend *backend)
   XISetMask (mask.mask, XI_FocusOut);
   XISetMask (mask.mask, XI_Motion);
 
+  if (include_motion)
+    XISetMask (mask.mask, XI_RawMotion);
+
   XISelectEvents (xdisplay, xwin, &mask, 1);
 }
 
+static void
+meta_backend_x11_cm_select_stage_events (MetaBackend *backend)
+{
+  select_xi_stage (backend, FALSE);
+}
+
+static void
+meta_backend_x11_cm_track_position (MetaBackend *x11, gboolean enabled)
+{
+  select_xi_stage (backend, enabled);
+}
+
 static void
 get_xkbrf_var_defs (Display           *xdisplay,
                     const char        *layouts,
@@ -386,6 +402,7 @@ meta_backend_x11_cm_class_init (MetaBackendX11CmClass *klass)
   backend_class->select_stage_events = meta_backend_x11_cm_select_stage_events;
   backend_class->lock_layout_group = meta_backend_x11_cm_lock_layout_group;
   backend_class->set_keymap = meta_backend_x11_cm_set_keymap;
+  backend_class->track_position = meta_backend_x11_cm_track_position;
 
   backend_x11_class->handle_host_xevent = meta_backend_x11_cm_handle_host_xevent;
   backend_x11_class->translate_device_event = meta_backend_x11_cm_translate_device_event;

src/backends/x11/meta-backend-x11.c

@@ -207,6 +207,8 @@ handle_input_event (MetaBackendX11 *x11,
 
       if (input_event->evtype == XI_DeviceChanged)
         handle_device_change (x11, input_event);
+      else if (input_event->evtype == XI_RawMotion)
+        meta_backend_cursor_position_changed (META_BACKEND (x11));
       else
         maybe_spoof_event_as_stage_event (x11, input_event);
     }

src/backends/x11/nested/meta-backend-x11-nested.c

@@ -61,7 +61,8 @@ meta_backend_x11_nested_update_screen_size (MetaBackend *backend,
 }
 
 static void
-meta_backend_x11_nested_select_stage_events (MetaBackend *backend)
+select_xi_stage (MetaBackend *backend,
+                 gboolean     include_motion)
 {
   MetaBackendX11 *x11 = META_BACKEND_X11 (backend);
   Display *xdisplay = meta_backend_x11_get_xdisplay (x11);
@@ -79,6 +80,9 @@ meta_backend_x11_nested_select_stage_events (MetaBackend *backend)
   XISetMask (mask.mask, XI_FocusOut);
   XISetMask (mask.mask, XI_Motion);
 
+  if (include_motion)
+    XISetMask (mask.mask, XI_RawMotion);
+
   /*
    * When we're an X11 compositor, we can't take these events or else replaying
    * events from our passive root window grab will cause them to come back to
@@ -91,6 +95,16 @@ meta_backend_x11_nested_select_stage_events (MetaBackend *backend)
   XISetMask (mask.mask, XI_TouchUpdate);
 
   XISelectEvents (xdisplay, xwin, &mask, 1);
+}
+
+static void
+meta_backend_x11_nested_select_stage_events (MetaBackend *backend)
+{
+  select_xi_stage (backend, FALSE);
+
+  MetaBackendX11 *x11 = META_BACKEND_X11 (backend);
+  Display *xdisplay = meta_backend_x11_get_xdisplay (x11);
+  Window xwin = meta_backend_x11_get_xwindow (x11);
 
   /*
    * We have no way of tracking key changes when the stage doesn't have focus,
@@ -105,6 +119,12 @@ meta_backend_x11_nested_select_stage_events (MetaBackend *backend)
                xwa.your_event_mask | FocusChangeMask | KeymapStateMask);
 }
 
+static void
+meta_backend_x11_nested_track_position (MetaBackend *x11, gboolean enabled)
+{
+  select_xi_stage (backend, enabled);
+}
+
 static void
 meta_backend_x11_nested_lock_layout_group (MetaBackend *backend,
                                            guint        idx)
@@ -178,6 +198,7 @@ meta_backend_x11_nested_class_init (MetaBackendX11NestedClass *klass)
   backend_class->select_stage_events = meta_backend_x11_nested_select_stage_events;
   backend_class->lock_layout_group = meta_backend_x11_nested_lock_layout_group;
   backend_class->set_keymap = meta_backend_x11_nested_set_keymap;
+  backend_class->track_position = meta_backend_x11_nested_track_position;
 
   backend_x11_class->handle_host_xevent = meta_backend_x11_nested_handle_host_xevent;
   backend_x11_class->translate_device_event = meta_backend_x11_nested_translate_device_event;

src/meta/meta-cursor-tracker.h

@@ -53,4 +53,7 @@ void           meta_cursor_tracker_get_pointer (MetaCursorTracker   *tracker,
 void           meta_cursor_tracker_set_pointer_visible (MetaCursorTracker *tracker,
                                                         gboolean           visible);
 
+void           meta_cursor_tracker_enable_track_position (MetaCursorTracker *tracker);
+void           meta_cursor_tracker_disable_track_position (MetaCursorTracker *tracker);
+
 #endif