System.Drawing.Drawing2D.GraphicsPath.AddPie C# (CSharp) Method

        public void AddPie(float x, float y, float width, float height, float startAngle, float sweepAngle)
        {
            float sin_alpha, cos_alpha;

            float rx = width / 2;
            float ry = height / 2;

            /* center */
            float cx = x + rx;
            float cy = y + ry;

            /* angles in radians */
            float alpha = (float)(startAngle * Math.PI / 180);

            /* adjust angle for ellipses */
            alpha = (float) Math.Atan2 (rx * Math.Sin (alpha), ry * Math.Cos (alpha));

            sin_alpha = (float)Math.Sin (alpha);
            cos_alpha = (float)Math.Cos (alpha);

            /* move to center */
            Append (cx, cy, PathPointType.Start, false);

            /* draw pie edge */
            if (Math.Abs (sweepAngle) < 360)
                Append (cx + rx * cos_alpha, cy + ry * sin_alpha, PathPointType.Line, false);

            /* draw the arcs */
            AppendArcs (x, y, width, height, startAngle, sweepAngle);

            /* draw pie edge */
            if (Math.Abs (sweepAngle) < 360)
                Append (cx, cy, PathPointType.Line, false);

            CloseFigure ();
        }

        public override GraphicsPath getGraphicsPathNoOffsetRoute()
        {
            GraphicsPath path = new GraphicsPath();
            RectangleF rect = getRect();
            try
            {
                path.AddPie(rect.X, rect.Y, rect.Width, rect.Height, StartAngle, EndAngle);
            }
            catch (Exception ex)
            {

                rect.X = _X + _XAdd;
                rect.Y = _Y + _YAdd;
                rect.Width = 10;
                rect.Height = 10;
                path.AddPie(rect.X, rect.Y, rect.Width, rect.Height, StartAngle, EndAngle);
                ////ClsErrorFile.WriteLine("这里是一个扇形出现参数错误，异常处理是构造一个默认宽和高都是10，角度为0和90的扇形", ex);
                //throw;

                //throw;
            }

            return path;
            //return base.getGraphicsPath();
        }