[gtk/gtk-3-22] Menu: Fix broken navigation triangle/hysteresis

[Daniel Boles <dboles src gnome org>]

commit f443dbe8c1dcaee5ba1c5fc59c36a2ed9255c0d3
Author: Sam Douglas <sam douglas32 gmail com>
Date:   Tue Nov 15 02:57:43 2016 +0000

    Menu: Fix broken navigation triangle/hysteresis
    
    This issue was caused when mouse coordinates were changed to floating
    point values in commit e8b38fedbd8961df4aaaa75b122a06ddc68e75f2.
    
    This patch floors the event->x_root and event->y_root values when
    setting the navigation region, so the previous behaviour is restored.
    
    https://gitlab.gnome.org/GNOME/gtk/issues/450

 gtk/gtkmenu.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)
---
diff --git a/gtk/gtkmenu.c b/gtk/gtkmenu.c
index e87c624390..c2f4b760f5 100644
--- a/gtk/gtkmenu.c
+++ b/gtk/gtkmenu.c
@@ -4822,6 +4822,8 @@ gtk_menu_set_submenu_navigation_region (GtkMenu          *menu,
   gint submenu_top = 0;
   gint submenu_bottom = 0;
   gint width = 0;
+  gint x_root = 0;
+  gint y_root = 0;
   GtkWidget *event_widget;
   GtkMenuPopdownData *popdown_data;
   GdkWindow *window;
@@ -4839,6 +4841,9 @@ gtk_menu_set_submenu_navigation_region (GtkMenu          *menu,
 
   width = gdk_window_get_width (gtk_widget_get_window (event_widget));
 
+  x_root = floor (event->x_root);
+  y_root = floor (event->y_root);
+
   if (event->x >= 0 && event->x < width)
     {
       gtk_menu_stop_navigating_submenu (menu);
@@ -4851,20 +4856,20 @@ gtk_menu_set_submenu_navigation_region (GtkMenu          *menu,
         {
           /* right */
           priv->navigation_x = submenu_left;
-          priv->navigation_width = event->x_root - submenu_left;
+          priv->navigation_width = x_root - submenu_left;
         }
       else
         {
           /* left */
           priv->navigation_x = submenu_right;
-          priv->navigation_width = event->x_root - submenu_right;
+          priv->navigation_width = x_root - submenu_right;
         }
 
       if (event->y < 0)
         {
           /* top */
-          priv->navigation_y = event->y_root;
-          priv->navigation_height = submenu_top - event->y_root - NAVIGATION_REGION_OVERSHOOT;
+          priv->navigation_y = y_root;
+          priv->navigation_height = submenu_top - y_root - NAVIGATION_REGION_OVERSHOOT;
 
           if (priv->navigation_height >= 0)
             return;
@@ -4872,8 +4877,8 @@ gtk_menu_set_submenu_navigation_region (GtkMenu          *menu,
       else
         {
           /* bottom */
-          priv->navigation_y = event->y_root;
-          priv->navigation_height = submenu_bottom - event->y_root + NAVIGATION_REGION_OVERSHOOT;
+          priv->navigation_y = y_root;
+          priv->navigation_height = submenu_bottom - y_root + NAVIGATION_REGION_OVERSHOOT;
 
           if (priv->navigation_height <= 0)
             return;