Line.h

/*
 * This file is part of ALVAR, A Library for Virtual and Augmented Reality.
 *
 * Copyright 2007-2012 VTT Technical Research Centre of Finland
 *
 * Contact: VTT Augmented Reality Team <alvar.info@vtt.fi>
 *          <http://www.vtt.fi/multimedia/alvar.html>
 *
 * ALVAR is free software; you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with ALVAR; if not, see
 * <http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html>.
 */

#ifndef _LINE_H
#define _LINE_H

/**
 * \file Line.h
 *
 * \brief This file implements a parametrized line.
 */

/*****************************************************************************
 ******************************  I N C L U D E  ******************************
 ****************************************************************************/

#include "Alvar.h"
#include "Util.h"

namespace alvar {


/*****************************************************************************
 *
 ***  class Line
 *
 * Struct representing a line. The line is parametrized by its center and
 * direction vector.  The advantage of this form is that vertical lines can
 * be represented as compared to the common slope/intercept form.
 *
 *****************************************************************************/

class ALVAR_EXPORT Line
   {
   public:
      /**
   * \brief Constructor.
   * \param params params[0] and params[1] are the x and y components of the direction vector, params[2] and params[3]
   * \are the x and y coordinates of the line center.
   */
      Line() = default;

      explicit Line(const cv::Vec4f& params)
         {
         c.x = params[2];
         c.y = params[3];
         s.x = params[0];
         s.y = params[1];

         return;

         }

      Line(const Line& src) : c(src.c), s(src.s)
         {
         return;
         }

      Line& operator=(const Line& rhs)
         {
         if (this != &rhs)
            {
            c = rhs.c;
            s = rhs.s;
            } // end if

         return (*this);

         }

      const PointDouble& GetCenter() const
         {
         return(c);
         }

      const PointDouble& GetDirection() const
         {
         return(s);
         }

      /**
       * \brief Calculates an intersection point of two lines.
       * \param l1	First line.
       * \param l2	Second line.
       * \return		Intersection point.
       */
      static PointDouble Intersection(const Line& l1, const Line& l2);

      PointDouble Intersection(const Line& other) const
         {
         return(Intersection(*this, other));
         }

      /**
       * \brief Fit lines to vector of points.
       * \param lines		Resulting set of lines.
       * \param corners	Index list of line breaks.
       * \param edge		Vector of points (pixels) where the line is fitted.
       * \param grey		In the future, we may want to fit lines directly to grayscale image instead of thresholded edge.
       */
      static int FitLines(std::vector<Line> &lines, const std::vector<int>& corners,
                          const std::vector<PointInt>& edge, cv::Mat& grey);

   protected:

      /**
    * \brief Line center.
   */
      PointDouble c; // center

      /**
    * \brief Direction vector.
   */
      PointDouble s; // direction vector

   }; // end of class Line

} // namespace alvar 

#endif