Bugfix

DrawGraph/ArrowLineBase.cs

@@ -1,7 +1,7 @@
 //----------------------------------------------
 // ArrowLineBase.cs (c) 2007 by Charles Petzold
 //----------------------------------------------
-using System;
+
 using System.Windows;
 using System.Windows.Media;
 using System.Windows.Shapes;
@@ -34,7 +34,7 @@ namespace DrawGraph
             DependencyProperty.Register("ArrowAngle",
                 typeof(double), typeof(ArrowLineBase),
                 new FrameworkPropertyMetadata(45.0,
-                        FrameworkPropertyMetadataOptions.AffectsMeasure));
+                    FrameworkPropertyMetadataOptions.AffectsMeasure));
 
         /// <summary>
         ///     Gets or sets the angle between the two sides of the arrowhead.
@@ -42,7 +42,7 @@ namespace DrawGraph
         public double ArrowAngle
         {
             set { SetValue(ArrowAngleProperty, value); }
-            get { return (double)GetValue(ArrowAngleProperty); }
+            get { return (double) GetValue(ArrowAngleProperty); }
         }
 
         /// <summary>
@@ -52,7 +52,7 @@ namespace DrawGraph
             DependencyProperty.Register("ArrowLength",
                 typeof(double), typeof(ArrowLineBase),
                 new FrameworkPropertyMetadata(12.0,
-                        FrameworkPropertyMetadataOptions.AffectsMeasure));
+                    FrameworkPropertyMetadataOptions.AffectsMeasure));
 
         /// <summary>
         ///     Gets or sets the length of the two sides of the arrowhead.
@@ -60,7 +60,7 @@ namespace DrawGraph
         public double ArrowLength
         {
             set { SetValue(ArrowLengthProperty, value); }
-            get { return (double)GetValue(ArrowLengthProperty); }
+            get { return (double) GetValue(ArrowLengthProperty); }
         }
 
         /// <summary>
@@ -70,7 +70,7 @@ namespace DrawGraph
             DependencyProperty.Register("ArrowEnds",
                 typeof(ArrowEnds), typeof(ArrowLineBase),
                 new FrameworkPropertyMetadata(ArrowEnds.End,
-                        FrameworkPropertyMetadataOptions.AffectsMeasure));
+                    FrameworkPropertyMetadataOptions.AffectsMeasure));
 
         /// <summary>
         ///     Gets or sets the property that determines which ends of the
@@ -79,7 +79,7 @@ namespace DrawGraph
         public ArrowEnds ArrowEnds
         {
             set { SetValue(ArrowEndsProperty, value); }
-            get { return (ArrowEnds)GetValue(ArrowEndsProperty); }
+            get { return (ArrowEnds) GetValue(ArrowEndsProperty); }
         }
 
         /// <summary>
@@ -89,7 +89,7 @@ namespace DrawGraph
             DependencyProperty.Register("IsArrowClosed",
                 typeof(bool), typeof(ArrowLineBase),
                 new FrameworkPropertyMetadata(false,
-                        FrameworkPropertyMetadataOptions.AffectsMeasure));
+                    FrameworkPropertyMetadataOptions.AffectsMeasure));
 
         /// <summary>
         ///     Gets or sets the property that determines if the arrow head
@@ -98,7 +98,7 @@ namespace DrawGraph
         public bool IsArrowClosed
         {
             set { SetValue(IsArrowClosedProperty, value); }
-            get { return (bool)GetValue(IsArrowClosedProperty); }
+            get { return (bool) GetValue(IsArrowClosedProperty); }
         }
 
         /// <summary>
@@ -143,29 +143,28 @@ namespace DrawGraph
                     // Draw the arrow at the end of the line.
                     if ((ArrowEnds & ArrowEnds.End) == ArrowEnds.End)
                     {
-                        Point pt1 = count == 1 ? pathfigLine.StartPoint :
-                                                 polysegLine.Points[count - 2];
+                        Point pt1 = count == 1 ? pathfigLine.StartPoint : polysegLine.Points[count - 2];
                         Point pt2 = polysegLine.Points[count - 1];
                         pathgeo.Figures.Add(CalculateArrow(pathfigHead2, pt1, pt2));
                     }
                 }
+
                 return pathgeo;
             }
         }
 
         PathFigure CalculateArrow(PathFigure pathfig, Point pt1, Point pt2)
         {
-            Matrix matx = new Matrix();
-            Vector vect = pt1 - pt2;
+            var matx = new System.Windows.Media.Matrix();
+            var vect = pt1 - pt2;
             vect.Normalize();
             vect *= ArrowLength;
 
-            PolyLineSegment polyseg = pathfig.Segments[0] as PolyLineSegment;
+            var polyseg = pathfig.Segments[0] as PolyLineSegment;
             polyseg.Points.Clear();
             matx.Rotate(ArrowAngle / 2);
             pathfig.StartPoint = pt2 + vect * matx;
             polyseg.Points.Add(pt2);
-
             matx.Rotate(-ArrowAngle);
             polyseg.Points.Add(pt2 + vect * matx);
             pathfig.IsClosed = IsArrowClosed;

DrawGraph/Settings.cs

@@ -15,8 +15,15 @@ namespace DrawGraph
 
         public static void ClearCanvas(Edge[] edges, Vertex[] vertices)
         {
-            Array.Clear(edges, 0, edges.Length);
-            Array.Clear(vertices, 0, vertices.Length);
+            if (edges != null && vertices != null)
+            {
+                Array.Clear(edges, 0, edges.Length);
+                Array.Clear(vertices, 0, vertices.Length);
+            }
+            else
+            {
+                throw new NullReferenceException();
+            }
         }
 
         public static void RemoveAllEdges(Canvas canvas, Line[] lines, Edge[] edges)