[gtk+] wayland: attempt to determine the possible parent surface for popups

[Cosimo Cecchi <cosimoc src gnome org>]

commit fbc0572068cadb8a163f5a10f0209e5fb39735da
Author: Thomas Wood <thomas wood intel com>
Date:   Fri Feb 15 11:16:51 2013 +0000

    wayland: attempt to determine the possible parent surface for popups
    
    Use the surface beneath the device that created the grab as the transient
    parent for the popup surfaces.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=693913

 gdk/wayland/gdkdevice-wayland.c  |    2 ++
 gdk/wayland/gdkprivate-wayland.h |    1 +
 gdk/wayland/gdkwindow-wayland.c  |   26 ++++++++++++++++++++++++--
 3 files changed, 27 insertions(+), 2 deletions(-)
---
diff --git a/gdk/wayland/gdkdevice-wayland.c b/gdk/wayland/gdkdevice-wayland.c
index 90ecb17..495b8ef 100644
--- a/gdk/wayland/gdkdevice-wayland.c
+++ b/gdk/wayland/gdkdevice-wayland.c
@@ -261,6 +261,7 @@ gdk_wayland_device_grab (GdkDevice    *device,
        * compositor.
        */
       _gdk_wayland_window_set_device_grabbed (window,
+                                              device,
                                               wayland_device->wl_seat,
                                               time_);
     }
@@ -293,6 +294,7 @@ gdk_wayland_device_ungrab (GdkDevice *device,
       if (wayland_device->pointer_grab_window)
         _gdk_wayland_window_set_device_grabbed (wayland_device->pointer_grab_window,
                                                 NULL,
+                                                NULL,
                                                 0);
     }
 }
diff --git a/gdk/wayland/gdkprivate-wayland.h b/gdk/wayland/gdkprivate-wayland.h
index a80dd15..6f07059 100644
--- a/gdk/wayland/gdkprivate-wayland.h
+++ b/gdk/wayland/gdkprivate-wayland.h
@@ -155,6 +155,7 @@ void _gdk_wayland_display_manager_remove_display (GdkDisplayManager *manager,
                                                  GdkDisplay        *display);
 
 void _gdk_wayland_window_set_device_grabbed (GdkWindow      *window,
+                                             GdkDevice      *device,
                                              struct wl_seat *seat,
                                              guint32         time_);
 
diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index 920ead2..f5dcd7e 100644
--- a/gdk/wayland/gdkwindow-wayland.c
+++ b/gdk/wayland/gdkwindow-wayland.c
@@ -130,6 +130,7 @@ struct _GdkWindowImplWayland
   GdkGeometry geometry_hints;
   GdkWindowHints geometry_mask;
 
+  GdkDevice *grab_device;
   struct wl_seat *grab_input_seat;
   guint32 grab_time;
 
@@ -563,15 +564,34 @@ gdk_wayland_window_map (GdkWindow *window)
   GdkWindowImplWayland *parent;
   GdkWaylandDisplay *wayland_display =
     GDK_WAYLAND_DISPLAY (gdk_window_get_display (window));
+  GdkWindow *transient_for;
 
   if (!impl->mapped)
     {
-      if (impl->transient_for)
+      /* Popup menus can appear without a transient parent, which means they
+       * cannot be positioned properly on Wayland. This attempts to guess the
+       * surface they should be positioned with by finding the surface beneath
+       * the device that created the grab for the popup window */
+
+      if (!impl->transient_for && impl->hint == GDK_WINDOW_TYPE_HINT_POPUP_MENU)
+        {
+          transient_for = gdk_device_get_window_at_position (impl->grab_device, NULL, NULL);
+          transient_for = gdk_window_get_toplevel (transient_for);
+
+          /* start the popup at the position of the device that holds the grab */
+          gdk_window_get_device_position (transient_for,
+                                          impl->grab_device,
+                                          &window->x, &window->y, NULL);
+        }
+      else
+        transient_for = impl->transient_for;
+
+      if (transient_for)
         {
           struct wl_seat *grab_input_seat = NULL;
           GdkWindowImplWayland *tmp_impl;
 
-          parent = GDK_WINDOW_IMPL_WAYLAND (impl->transient_for->impl);
+          parent = GDK_WINDOW_IMPL_WAYLAND (transient_for->impl);
 
           /* Use the device that was used for the grab as the device for
            * the popup window setup - so this relies on GTK+ taking the
@@ -1677,6 +1697,7 @@ _gdk_window_impl_wayland_class_init (GdkWindowImplWaylandClass *klass)
 
 void
 _gdk_wayland_window_set_device_grabbed (GdkWindow      *window,
+                                        GdkDevice      *device,
                                         struct wl_seat *seat,
                                         guint32         time_)
 {
@@ -1686,6 +1707,7 @@ _gdk_wayland_window_set_device_grabbed (GdkWindow      *window,
 
   impl = GDK_WINDOW_IMPL_WAYLAND (window->impl);
 
+  impl->grab_device = device;
   impl->grab_input_seat = seat;
   impl->grab_time = time_;
 }