[chronojump] forcesensor analyze ab scale fixed at a, b extremes. fixes: https://gitlab.gnome.org/GNOME/chronojum

[Xavier de Blas <xaviblas src gnome org>]

commit 79797f427d7238e64e1c185f970e03d3344f9429
Author: Xavier de Blas <xaviblas gmail com>
Date:   Tue Dec 11 13:21:12 2018 +0100

    forcesensor analyze ab scale fixed at a, b extremes. fixes: 
https://gitlab.gnome.org/GNOME/chronojump/issues/68

 src/gui/forceSensorAnalyze.cs | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)
---
diff --git a/src/gui/forceSensorAnalyze.cs b/src/gui/forceSensorAnalyze.cs
index b9b6e993..62e63b39 100644
--- a/src/gui/forceSensorAnalyze.cs
+++ b/src/gui/forceSensorAnalyze.cs
@@ -938,8 +938,23 @@ public partial class ChronoJumpWindow
                if(updateForceSensorHScales)
                {
                        int difference = Convert.ToInt32(hscale_force_sensor_ai_ab.Value) - 
force_sensor_last_ab;
-                       hscale_force_sensor_ai_a.Value += difference;
-                       hscale_force_sensor_ai_b.Value += difference;
+                       int aValue = Convert.ToInt32(hscale_force_sensor_ai_a.Value);
+                       int bValue = Convert.ToInt32(hscale_force_sensor_ai_b.Value);
+                       //if a or b are at max, don't move the ab to the right
+                       //if a or b are at min, don't move the ab to the left
+                       if(
+                                       ( difference > 0 && aValue < fsAI.GetLength() -2 && bValue < 
fsAI.GetLength() -2 ) ||
+                                       ( difference < 0 && aValue > 1 && bValue > 1 ) )
+                       {
+                               //move a and b
+                               hscale_force_sensor_ai_a.Value += difference;
+                               hscale_force_sensor_ai_b.Value += difference;
+                       } else {
+                               //do not move ab (so also a and b will not be moved)
+                               updateForceSensorHScales = false;
+                               hscale_force_sensor_ai_ab.Value = force_sensor_last_ab;
+                               updateForceSensorHScales = true;
+                       }
                }
 
                force_sensor_last_ab = Convert.ToInt32(hscale_force_sensor_ai_ab.Value);