/*
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2023 by Inria. All rights reserved.
 *
 * This software is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * See the file LICENSE.txt at the root directory of this source
 * distribution for additional information about the GNU GPL.
 *
 * For using ViSP with software that can not be combined with the GNU
 * GPL, please contact Inria about acquiring a ViSP Professional
 * Edition License.
 *
 * See https://visp.inria.fr for more information.
 *
 * This software was developed at:
 * Inria Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 *
 * If you have questions regarding the use of this file, please contact
 * Inria at visp@inria.fr
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 * Basic moment descriptor
 */

/*!
  \file vpMomentBasic.h
  \brief Basic moment descriptor (also called m).
*/

#ifndef _vpMomentBasic_h_
#define _vpMomentBasic_h_

#include <visp3/core/vpMoment.h>

/*!
  \class vpMomentBasic

  \ingroup group_core_moments

  \brief This class defines the 2D basic moment \f$m_{ij}\f$.
    This class is a wrapper for vpMomentObject wich allows to use it as a
  moment. This enables all common operations such as adding to a
  vpMomentDatabase.

  In the case of a dense object \e O, 2D basic moments are defined by:
  \f[m_{ij} = \int \int_{O} x^j y^j dx dy\f]

  In the case of a discrete set of \e n points, the basic moments are defined
  by \f[m_{ij} = \sum_{k=1}^{n} x_k^j y_k^j \f]

  The selection of a dense or discrete object is done in vpMomentObject.
  The maximum order of vpMomentBasic is the same as that of vpMomentObject
  (ie: \f$i+j \leq \f$ vpMomentObject::getOrder).

  Note that in the continuous case, the basic moment \f$m_{00}\f$ corresponds
  to the surface \f$a\f$ of the object. In the discrete case, it is the number
  of discrete points \f$n\f$.
*/

class VISP_EXPORT vpMomentBasic : public vpMoment
{
public:
  vpMomentBasic();
  virtual ~vpMomentBasic(){};

  void compute();
  const std::vector<double> &get() const;
  double get(unsigned int i, unsigned int j) const;
  /*!
    Moment name.
    */
  const char *name() const { return "vpMomentBasic"; }
  friend VISP_EXPORT std::ostream &operator<<(std::ostream &os, const vpMomentBasic &v);
  void printDependencies(std::ostream &os) const;
};
#endif
