GraphicsPath.AddCurve Method (PointF)
Adds a spline curve to the current figure. A cardinal spline curve is used because the curve travels through each of the points in the array.
Assembly: System.Drawing (in System.Drawing.dll)
The user must keep the original points if they are needed. The original points are converted to cubic Bézier control points internally, therefore there is no mechanism for returning the original points.
Available since 1.1