MARKUS

        /// return ArrowControl_Multi's area

        /// </summary>

        /// <author>humkyung</author>

        /// <date>2019.06.13</date>

        public override Rect ItemRect

        {

            get

            {

                double dMinX = Math.Min(this.StartPoint.X, this.EndPoint.X);

                dMinX = Math.Min(this.MiddlePoint.X, dMinX);

                double dMinY = Math.Min(this.StartPoint.Y, this.EndPoint.Y);

                dMinY = Math.Min(this.MiddlePoint.Y, dMinY);

                double dMaxX = Math.Max(this.StartPoint.X, this.EndPoint.X);

                dMaxX = Math.Max(this.MiddlePoint.X, dMaxX);

                double dMaxY = Math.Max(this.StartPoint.Y, this.EndPoint.Y);

                dMaxY = Math.Max(this.MiddlePoint.Y, dMaxY);

                return new Rect(new Point(dMinX, dMinY), new Point(dMaxX, dMaxY));

            }

        }

        /// <summary>