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

        void AppendCurve(PointF [] points, PointF [] tangents, int offset, int length, CurveType type)
        {
            PathPointType ptype = ((type == CurveType.Close) || (points.Length == 0)) ? PathPointType.Start : PathPointType.Line;
            int i;

            AppendPoint (points [offset], ptype, true);
            for (i = offset; i < offset + length; i++) {
                int j = i + 1;

                float x1 = points [i].X + tangents [i].X;
                float y1 = points [i].Y + tangents [i].Y;

                float x2 = points [j].X - tangents [j].X;
                float y2 = points [j].Y - tangents [j].Y;

                float x3 = points [j].X;
                float y3 = points [j].Y;

                AppendBezier (x1, y1, x2, y2, x3, y3);
            }

                /* complete (close) the curve using the first point */
            if (type == CurveType.Close) {
                float x1 = points [i].X + tangents [i].X;
                float y1 = points [i].Y + tangents [i].Y;

                float x2 = points [0].X - tangents [0].X;
                float y2 = points [0].Y - tangents [0].Y;

                float x3 = points [0].X;
                float y3 = points [0].Y;

                AppendBezier (x1, y1, x2, y2, x3, y3);
                CloseFigure ();
            }
        }