/// <summary>

    /// 图形笔

    /// </summary>

    public class ImageStroke : Stroke

    {

        private string imageFile_;

        private System.Windows.Media.ImageSource imageSource_;

        private Point curPoint;

        public ImageStroke(System.Windows.Input.StylusPointCollection points, DrawingAttributes da, string file)

            : base(points, da)

        {

            this.imageFile_ = file;

            this.imageSource_ = new System.Windows.Media.Imaging.BitmapImage(new Uri( this.imageFile_));

        }

        protected override void DrawCore(System.Windows.Media.DrawingContext drawingContext, DrawingAttributes drawingAttributes)

        {

            double num = drawingAttributes.Width + 20.0;

            System.Windows.Media.StreamGeometry streamGeometry = new System.Windows.Media.StreamGeometry();

            using (System.Windows.Media.StreamGeometryContext streamGeometryContext = streamGeometry.Open())

            {

                streamGeometryContext.BeginFigure((Point)base.StylusPoints[], false, false);

                drawingContext.DrawImage(this.imageSource_, new Rect(((Point)base.StylusPoints[]).X - num / 2.0, ((Point)base.StylusPoints[]).Y - num / 2.0, num, num));

                this.curPoint = (Point)base.StylusPoints[];

                foreach (System.Windows.Input.StylusPoint current in base.StylusPoints)

                {

                    ImageStroke.DrawImage(ref this.curPoint, (Point)current, num, drawingContext, this.imageSource_);

                }

            }

        }

        public static double GetDistance(Point a, Point b)

        {

            return System.Math.Abs(Point.Subtract(a, b).Length);

        }

        public static Point GetPointBetween(Point a, Point b, double len)

        {

            Vector vector = Point.Subtract(a, b);

            vector.Normalize();

            vector = Vector.Multiply(vector, len);

            return Point.Subtract(a, vector);

        }

        public static void DrawImage(ref Point a, Point b, double width, System.Windows.Media.DrawingContext drawingContext, System.Windows.Media.ImageSource imageSource)

        {

            for (double distance = ImageStroke.GetDistance(a, b); distance >= width; distance = ImageStroke.GetDistance(a, b))

            {

                Point pointBetween = ImageStroke.GetPointBetween(a, b, width);

                drawingContext.DrawImage(imageSource, new Rect(pointBetween.X - width / 2.0, pointBetween.Y - width / 2.0, width, width));

                a = pointBetween;

            }

        }

    }