backdiagonal2d.hh

// Copyright (C) 2007, 2008, 2009 EPITA Research and Development Laboratory (LRDE)
//
// This file is part of Olena.
//
// Olena 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, version 2 of the License.
//
// Olena 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
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Olena.  If not, see <http://www.gnu.org/licenses/>.
//
// As a special exception, you may use this file as part of a free
// software project without restriction.  Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to produce
// an executable, this file does not by itself cause the resulting
// executable to be covered by the GNU General Public License.  This
// exception does not however invalidate any other reasons why the
// executable file might be covered by the GNU General Public License.

#ifndef MLN_CANVAS_BROWSING_BACKDIAGONAL2D_HH
# define MLN_CANVAS_BROWSING_BACKDIAGONAL2D_HH


# include <mln/core/concept/browsing.hh>
# include <mln/core/concept/image.hh>


namespace mln
{

  namespace canvas
  {

    namespace browsing
    {


      struct backdiagonal2d_t : public Browsing< backdiagonal2d_t >
      {
        template <typename F>
        void operator()(F& f) const;
      };

      extern const backdiagonal2d_t backdiagonal2d;



# ifndef MLN_INCLUDE_ONLY

      const backdiagonal2d_t backdiagonal2d;

      template <typename F>
      inline
      void
      backdiagonal2d_t::operator()(F& f) const
      {
        trace::entering("canvas::browsing::backdiagonal2d");

        typedef typename F::I I;
        typedef mln_deduce(I, psite, delta) dpsite;
        typedef mln_psite(I) psite;

        // Directions
        dpsite dp_first(-1, 0);
        dpsite dp_second(0, 1);
        dpsite dp_diag(1, 1);

        mln_deduce(I, psite, delta) diag;

        psite
          pmin = f.input.domain().pmin(),
          pmax = f.input.domain().pmax();

        // Start at the bottom left corner.
        f.p[0] = pmax[0];
        f.p[1] = pmin[1];

        f.init();

        while (f.input.domain().has(f.p))
        {
          psite start_diag = f.p;
          // Browse one diag.
          f.init_diag();
          while (f.input.domain().has(f.p))
          {
            f.next();
            f.p = f.p + dp_diag;
          }

          // Goto next diag start.
          f.p = start_diag + dp_first;
        }
        f.p = f.p - dp_first;

        f.p = f.p + dp_second;
        while (f.input.domain().has(f.p))
        {
          psite start_diag = f.p;

          // Browse one diag.
          f.init_diag();
          while (f.input.domain().has(f.p))
          {
            f.next();
            f.p = f.p + dp_diag;
          }
          f.p = f.p - dp_diag;

          // Goto next diag start.
          f.p = start_diag + dp_second;
        }

        f.final();
        trace::exiting("canvas::browsing::backdiagonal2d");
      }

# endif // ! MLN_INCLUDE_ONLY

    } // end of namespace mln::canvas::browsing

  } // end of namespace mln::canvas

} // end of namespace mln

#endif // ! MLN_CANVAS_BROWSING_BACKDIAGONAL2D_HH