wayland: Avoid spurious crossing events from master touch device

Only generate crossing events on wl_touch.down for the virtual master
device used for touch events, and only whenever this virtual device
actually moves across surfaces. This behavior resembles better what is
expected in X11, where the pointer is warped to the touch position
on XITouchBegin.

This avoids the double emission of leave events when the pointer
emulating touch is lifted, that crossing event will be instead
generated when/if the focus surface changes.

https://bugzilla.gnome.org/show_bug.cgi?id=766314

diff --git a/gdk/wayland/gdkdevice-wayland.c b/gdk/wayland/gdkdevice-wayland.c
index 2da74dea9edbdf77bf5bed130a29d1c0420e9743..1e3bc8336e80daa400522caec5c283067dd2377e 100644 (file)
--- a/gdk/wayland/gdkdevice-wayland.c
+++ b/gdk/wayland/gdkdevice-wayland.c
@@ -2071,6 +2071,33 @@ mimic_pointer_emulating_touch_info (GdkDevice           *device,
   pointer->surface_y = touch->y;
 }
 
+static void
+touch_handle_master_pointer_crossing (GdkWaylandSeat      *seat,
+                                      GdkWaylandTouchData *touch,
+                                      uint32_t             time)
+{
+  GdkWaylandPointerData *pointer;
+
+  pointer = GDK_WAYLAND_DEVICE (seat->touch_master)->pointer;
+
+  if (pointer->focus == touch->window)
+    return;
+
+  if (pointer->focus)
+    {
+      emulate_touch_crossing (pointer->focus, NULL,
+                              seat->touch_master, seat->touch, touch,
+                              GDK_LEAVE_NOTIFY, GDK_CROSSING_NORMAL, time);
+    }
+
+  if (touch->window)
+    {
+      emulate_touch_crossing (touch->window, NULL,
+                              seat->touch_master, seat->touch, touch,
+                              GDK_ENTER_NOTIFY, GDK_CROSSING_NORMAL, time);
+    }
+}
+
 static void
 touch_handle_down (void              *data,
                    struct wl_touch   *wl_touch,
@@ -2097,9 +2124,7 @@ touch_handle_down (void              *data,
 
   if (touch->initial_touch)
     {
-      emulate_touch_crossing (touch->window, NULL,
-                              seat->touch_master, seat->touch, touch,
-                              GDK_ENTER_NOTIFY, GDK_CROSSING_NORMAL, time);
+      touch_handle_master_pointer_crossing (seat, touch, time);
       GDK_WAYLAND_DEVICE(seat->touch_master)->emulating_touch = touch;
       mimic_pointer_emulating_touch_info (seat->touch_master, touch);
     }
@@ -2133,16 +2158,7 @@ touch_handle_up (void            *data,
   _gdk_wayland_display_deliver_event (seat->display, event);
 
   if (touch->initial_touch)
-    {
-      GdkWaylandPointerData *pointer_info;
-
-      emulate_touch_crossing (touch->window, NULL,
-                              seat->touch_master, seat->touch, touch,
-                              GDK_LEAVE_NOTIFY, GDK_CROSSING_NORMAL, time);
-      GDK_WAYLAND_DEVICE(seat->touch_master)->emulating_touch = NULL;
-      pointer_info = GDK_WAYLAND_DEVICE (seat->touch_master)->pointer;
-      g_clear_object (&pointer_info->focus);
-    }
+    GDK_WAYLAND_DEVICE(seat->touch_master)->emulating_touch = NULL;
 
   gdk_wayland_seat_remove_touch (seat, id);
 }
@@ -2193,10 +2209,6 @@ touch_handle_cancel (void            *data,
     {
       touch = GDK_WAYLAND_DEVICE (wayland_seat->touch_master)->emulating_touch;
       GDK_WAYLAND_DEVICE (wayland_seat->touch_master)->emulating_touch = NULL;
-      emulate_touch_crossing (touch->window, NULL,
-                              wayland_seat->touch_master, wayland_seat->touch,
-                              touch, GDK_LEAVE_NOTIFY, GDK_CROSSING_NORMAL,
-                              GDK_CURRENT_TIME);
     }
 
   g_hash_table_iter_init (&iter, wayland_seat->touches);