quartz: fix coordinates for synthesized event

Of course, we must pass coordinates in the NSWindow coordinate system
when creating an NSEvent. This fixes drag icon positioning and makes
the icon slide back to the correct position when the drag is
canceled.

1 files changed, 19 insertions, 2 deletions

diff --git a/gtk/gtkdnd-quartz.c b/gtk/gtkdnd-quartz.c
index 6be1c150ae..44ab02099d 100644
--- a/gtk/gtkdnd-quartz.c
+++ b/gtk/gtkdnd-quartz.c
@@ -1108,7 +1108,7 @@ gtk_drag_begin_idle (gpointer arg)
 
   [nswindow dragImage:drag_image
                    at:point
-               offset:NSMakeSize(0, 0)
+               offset:NSZeroSize
                 event:info->nsevent
            pasteboard:pasteboard
                source:nswindow
@@ -1143,8 +1143,25 @@ gtk_drag_begin_internal (GtkWidget         *widget,
     {
       if (gdk_event_get_coords (event, &x, &y))
         {
+          /* We need to translate (x, y) to coordinates relative to the
+           * toplevel GdkWindow, which should be the GdkWindow backing
+           * nswindow. Then, we convert to the NSWindow coordinate system.
+           */
+          GdkWindow *window = event->any.window;
+          GdkWindow *toplevel = gdk_window_get_effective_toplevel (window);
+
+          while (window != toplevel)
+            {
+              double old_x = x;
+              double old_y = y;
+
+              gdk_window_coords_to_parent (window, old_x, old_y,
+                                           &x, &y);
+              window = gdk_window_get_effective_parent (window);
+            }
+
           point.x = x;
-          point.y = y;
+          point.y = gdk_window_get_height (window) - y;
         }
       time = (double)gdk_event_get_time (event);
     }