[gtk+] range: avoid setting slider coordinates to negative numbers

[Cosimo Cecchi <cosimoc src gnome org>]

commit f3e068bb31fffa6e647d021d334ee578049e9a4d
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Fri Mar 4 18:11:30 2016 -0800

    range: avoid setting slider coordinates to negative numbers
    
    This can happen if the theme sets a negative margin, but the coordinate
    should never be negative.

 gtk/gtkrange.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index 0d6c097..66cf084 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -2617,13 +2617,13 @@ update_initial_slider_position (GtkRange      *range,
 
   if (priv->orientation == GTK_ORIENTATION_VERTICAL)
     {
-      priv->slide_initial_slider_position = slider_alloc->y;
-      priv->slide_initial_coordinate_delta = y - slider_alloc->y;
+      priv->slide_initial_slider_position = MAX (0, slider_alloc->y);
+      priv->slide_initial_coordinate_delta = y - priv->slide_initial_slider_position;
     }
   else
     {
-      priv->slide_initial_slider_position = slider_alloc->x;
-      priv->slide_initial_coordinate_delta = x - slider_alloc->x;
+      priv->slide_initial_slider_position = MAX (0, slider_alloc->x);
+      priv->slide_initial_coordinate_delta = x - priv->slide_initial_slider_position;
     }
 }