From 8726c6d5d239a342f0267d1c2bf0c90fb051d7fb Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Mon, 23 Feb 2015 06:42:17 -0500
Subject: [PATCH] zoom scrolling: avoid 'jumping back'

We record the starting position on button press, but only
start the zoom mode when the long press timeout kicks in.
Depending on circumstances, this can cause a noticable jump.

Avoid this by resetting the recorded starting position after
the long press timeout. Suggested by Sebastian Keller.
---
 gtk/gtkrange.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index 404dc3a762..bd95ee9217 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -2437,7 +2437,12 @@ gtk_range_long_press_gesture_pressed (GtkGestureLongPress *gesture,
                                       gdouble              y,
                                       GtkRange            *range)
 {
-  update_zoom_state (range, TRUE);
+  if (!range->priv->zoom)
+    {
+      /* unset initial position so it can be calculated */
+      range->priv->slide_initial_slider_position = -1;
+      update_zoom_state (range, TRUE);
+    }
 }
 
 static void
-- 
2.30.2