[gtk+] GtkRange: Improve zoom handling a bit

[Matthias Clasen <matthiasc src gnome org>]

commit 93f9a81ac5d1a4239ad1aef60a126446810ef1ab
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Jun 20 20:26:42 2015 -0400

    GtkRange: Improve zoom handling a bit
    
    The calculation to update the initial slider position on zoom
    changes was not working correctly when using keys to toggle
    zoom on and off for scales. Avoid it by updating the position
    beforehand.

 gtk/gtkrange.c |   17 ++++++++---------
 1 files changed, 8 insertions(+), 9 deletions(-)
---
diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index 2f7cae5..edc0661 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -2418,17 +2418,18 @@ gtk_range_key_press (GtkWidget   *widget,
     {
       stop_scrolling (range);
 
-      update_slider_position (range,
-                             priv->slide_initial_coordinate_delta + priv->slide_initial_slider_position,
-                             priv->slide_initial_coordinate_delta + priv->slide_initial_slider_position);
-
       return TRUE;
     }
   else if (priv->in_drag &&
            (event->keyval == GDK_KEY_Shift_L ||
             event->keyval == GDK_KEY_Shift_R))
     {
+      if (priv->orientation == GTK_ORIENTATION_VERTICAL)
+        priv->slide_initial_slider_position = priv->slider.y;
+      else
+        priv->slide_initial_slider_position = priv->slider.x;
       update_zoom_state (range, !priv->zoom);
+
       return TRUE;
     }
 
@@ -2577,7 +2578,7 @@ gtk_range_multipress_gesture_pressed (GtkGestureMultiPress *gesture,
       if (priv->mouse_location != MOUSE_SLIDER)
         {
           gdouble slider_low_value, slider_high_value, new_value;
-          
+
           slider_high_value =
             coord_to_value (range,
                             priv->orientation == GTK_ORIENTATION_VERTICAL ?
@@ -2606,9 +2607,7 @@ gtk_range_multipress_gesture_pressed (GtkGestureMultiPress *gesture,
 
           /* Shift-click in the slider = fine adjustment */
           if (state_mask & GDK_SHIFT_MASK)
-            {
-              update_zoom_state (range, TRUE);
-            }
+            update_zoom_state (range, TRUE);
 
           slider = priv->slider;
         }
@@ -2930,7 +2929,6 @@ gtk_range_drag_gesture_update (GtkGestureDrag *gesture,
       priv->mouse_x = start_x + offset_x;
       priv->mouse_y = start_y + offset_y;
       priv->in_drag = TRUE;
-
       update_autoscroll_mode (range);
 
       if (priv->autoscroll_mode == GTK_SCROLL_NONE)
@@ -2946,6 +2944,7 @@ gtk_range_drag_gesture_begin (GtkGestureDrag *gesture,
 {
   if (range->priv->grab_location == MOUSE_SLIDER)
     gtk_gesture_set_state (range->priv->drag_gesture, GTK_EVENT_SEQUENCE_CLAIMED);
+
 }
 
 static void