public Bitmap GetTrail(int width, int height)
 {
     if (width > 0 && height > 0)
     {
         Bitmap   bmp    = new Bitmap(width, height);
         Graphics g      = Graphics.FromImage(bmp);
         PointF   center = new PointF(width / 2f, height / 2f);
         var      curr   = Trail.GetEnumerator();
         if (curr.MoveNext())
         {
             var prev = curr;
             while (curr.MoveNext())
             {
                 g.DrawLine(new Pen(colorTrail, 1), curr.Current.X + center.X, curr.Current.Y + center.Y,
                            prev.Current.X + center.X, prev.Current.Y + center.Y);
                 prev = curr;
             }
         }
         return(bmp);
     }
     return(null);
 }