notebook: Fix rounding error in vertical alignment of arrow

https://bugzilla.gnome.org/show_bug.cgi?id=707920

diff --git a/gtk/gtknotebook.c b/gtk/gtknotebook.c
index aab78ee16c2dcd829a67914a7069cb54293796cc..b582a0aef52a9046226cfa791a4ceb7a138d4ae9 100644 (file)
--- a/gtk/gtknotebook.c
+++ b/gtk/gtknotebook.c
@@ -27,6 +27,7 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <math.h>
 
 #include "gtknotebook.h"
 
@@ -2713,7 +2714,7 @@ gtk_notebook_get_arrow_rect (GtkNotebook     *notebook,
               else
                 rectangle->x = event_window_pos.x + event_window_pos.width - 2 * rectangle->width;
             }
-          rectangle->y = event_window_pos.y + (event_window_pos.height - rectangle->height) / 2;
+          rectangle->y = floor ((gdouble)event_window_pos.y + (event_window_pos.height - rectangle->height) / 2.0 + 0.5);
           break;
         }
     }