[longomatch] Fix moving positions outside of the field boundaries

[Andoni Morales Alastruey <amorales src gnome org>]

commit b5270e6a20296233bed8b80e95d26bed690bb38f
Author: Andoni Morales Alastruey <ylatuya gmail com>
Date:   Wed Oct 29 22:55:32 2014 +0100

    Fix moving positions outside of the field boundaries

 LongoMatch.Drawing/CanvasObjects/PositionObject.cs |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/LongoMatch.Drawing/CanvasObjects/PositionObject.cs 
b/LongoMatch.Drawing/CanvasObjects/PositionObject.cs
index a7e9654..2efc5b0 100644
--- a/LongoMatch.Drawing/CanvasObjects/PositionObject.cs
+++ b/LongoMatch.Drawing/CanvasObjects/PositionObject.cs
@@ -114,10 +114,10 @@ namespace LongoMatch.Drawing.CanvasObjects
                {
                        switch (sel.Position) {
                        case SelectionPosition.LineStart:
-                               Start = p;
+                               Start = new Point (Math.Max (p.X, 0), Math.Max (p.Y, 0));
                                break;
                        case SelectionPosition.LineStop:
-                               Stop = p;
+                               Stop = new Point (Math.Max (p.X, 0), Math.Max (p.Y, 0));
                                break;
                        default:
                                throw new Exception ("Unsupported move for circle:  " + sel.Position);