// Created on: 1991-03-12
// Created by: Michel CHAUVAT
// Copyright (c) 1991-1999 Matra Datavision
// Copyright (c) 1999-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _GProp_HeaderFile
#define _GProp_HeaderFile

#include <Standard.hxx>
#include <Standard_DefineAlloc.hxx>
#include <Standard_Handle.hxx>

#include <Standard_Real.hxx>
class gp_Pnt;
class gp_Mat;

//! This package defines algorithms to compute the global properties
//! of a set of points, a curve, a surface, a solid (non infinite
//! region of space delimited with geometric entities), a compound
//! geometric system (heterogeneous composition of the previous
//! entities).
//!
//! Global properties are:
//! . length, area, volume,
//! . centre of mass,
//! . axis of inertia,
//! . moments of inertia,
//! . radius of gyration.
//!
//! It provides also a class to compile the average point or
//! line of a set of points.
class GProp
{
public:
  DEFINE_STANDARD_ALLOC

  //! methods of package
  //! Computes the matrix Operator, referred to as the
  //! "Huyghens Operator" of a geometric system at the
  //! point Q of the space, using the following data:
  //! - Mass, i.e. the mass of the system,
  //! - G, the center of mass of the system.
  //! The "Huyghens Operator" is used to compute
  //! Inertia/Q, the matrix of inertia of the system at
  //! the point Q using Huyghens' theorem:
  //! Inertia/Q = Inertia/G + HOperator (Q, G, Mass)
  //! where Inertia/G is the matrix of inertia of the
  //! system relative to its center of mass as returned by
  //! the function MatrixOfInertia on any GProp_GProps object.
  Standard_EXPORT static void HOperator(const gp_Pnt& G,
                                        const gp_Pnt& Q,
                                        const double  Mass,
                                        gp_Mat&       Operator);
};

#endif // _GProp_HeaderFile
