/// <summary>
/// Returns this Polygon as convex polygon.
///
/// If this polygon is convex, a clone of it is returned.
/// If this polygon is concave, the Graham's (1972) "points to convex hull" enhanched algorythm is used to generate a convex polygon hull.
/// </summary>
/// <returns></returns>
public Polygon2 ToConvexPolygon()
{
var convexhull = ConvexHullBuilder.Convexhull(this.ToVertices().Distinct());
var clone = this.Clone() as Polygon2;
clone.Clear();
clone.AddRange(convexhull.ToVertices());
return(clone);
}