[gtk: 9/16] x11: Make gdk_surface_get_position() return relative position

[Benjamin Otte <otte src gnome org>]

commit 40693412d3ccdc875b3e8ea635ffcb5b6c75cbd4
Author: Jonas Ådahl <jadahl gmail com>
Date:   Sun Feb 16 00:28:01 2020 +0100

    x11: Make gdk_surface_get_position() return relative position
    
    The returned position should be relative to the parent surface, but
    GdkSurface::x,y were only managed properly for O-R windows. This makes
    it correct for regular windows too.

 gdk/x11/gdkdisplay-x11.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)
---
diff --git a/gdk/x11/gdkdisplay-x11.c b/gdk/x11/gdkdisplay-x11.c
index 7c143b52ff..1440eab426 100644
--- a/gdk/x11/gdkdisplay-x11.c
+++ b/gdk/x11/gdkdisplay-x11.c
@@ -994,11 +994,21 @@ gdk_x11_display_translate_event (GdkEventTranslator *translator,
            }
          if (!is_substructure)
            {
-              if (surface->x != event->configure.x ||
-                  surface->y != event->configure.y)
+              int new_abs_x, new_abs_y;
+
+              new_abs_x = event->configure.x;
+              new_abs_y = event->configure.y;
+
+              surface_impl->abs_x = new_abs_x;
+              surface_impl->abs_y = new_abs_y;
+
+              if (surface->parent)
                 {
-                  surface->x = event->configure.x;
-                  surface->y = event->configure.y;
+                  GdkX11Surface *parent_impl =
+                    GDK_X11_SURFACE (surface->parent);
+
+                  surface->x = new_abs_x - parent_impl->abs_x;
+                  surface->y = new_abs_y - parent_impl->abs_y;
                 }
 
               if (surface_impl->unscaled_width != xevent->xconfigure.width ||