/// <summary>
/// create lines from curve
/// </summary>
/// <param name="curve"></param>
/// <param name="vxs"></param>
/// <param name="x1"></param>
/// <param name="y1"></param>
/// <param name="p2x"></param>
/// <param name="p2y"></param>
/// <param name="p3x"></param>
/// <param name="p3y"></param>
/// <param name="x2"></param>
/// <param name="y2"></param>
public static void MakeLines(this Curve4 curve, VertexStore vxs, double x1, double y1,
double p2x, double p2y,
double p3x, double p3y,
double x2, double y2)
{
CreateBezierVxs4(vxs,
x1, y1,
p2x, p2y,
p3x, p3y,
x2, y2);
}