gradient.hh

// Copyright (C) 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_MORPHO_ELEMENTARY_GRADIENT_HH
# define MLN_MORPHO_ELEMENTARY_GRADIENT_HH


# include <mln/morpho/includes.hh>
# include <mln/accu/stat/min_max.hh>


namespace mln
{

  namespace morpho
  {

    namespace elementary
    {


      template <typename I, typename N>
      mln_concrete(I)
      gradient(const Image<I>& input, const Neighborhood<N>& nbh);


# ifndef MLN_INCLUDE_ONLY

      namespace internal
      {

        template <typename I, typename N>
        void
        gradient_tests(const Image<I>& input, const Neighborhood<N>& nbh)
        {
          mln_precondition(exact(input).is_valid());
          mln_precondition(exact(nbh).is_valid());
          (void) input;
          (void) nbh;
        }

      } // end of namespace mln::morpho::elementary::tests


      namespace impl
      {

        template <typename I, typename N>
        mln_concrete(I)
        gradient_on_function(const Image<I>& input_, const Neighborhood<N>& nbh_)
        {
          trace::entering("morpho::elementary::impl::gradient_on_function");

          const I& input = exact(input_);
          const N& nbh   = exact(nbh_);
          internal::gradient_tests(input, nbh);

          accu::stat::min_max<mln_value(I)> a;

          extension::adjust_duplicate(input, nbh);

          mln_concrete(I) output;
          initialize(output, input);

          mln_piter(I) p(input.domain());
          mln_niter(N) n(nbh, p);
          for_all(p)
            {
              a.take_as_init(input(p));
              for_all(n) if (input.has(n))
                a.take(input(n));
              output(p) = a.second() - a.first();
            }

          trace::exiting("morpho::elementary::impl::gradient_on_function");
          return output;
        }

        template <typename I, typename N>
        mln_concrete(I)
        gradient_on_set(const Image<I>& input_, const Neighborhood<N>& nbh_)
        {
          trace::entering("morpho::elementary::impl::gradient_on_set");

          const I& input = exact(input_);
          const N& nbh   = exact(nbh_);
          internal::gradient_tests(input, nbh);

          extension::adjust_duplicate(input, nbh);

          mln_concrete(I) output;
          initialize(output, input);
          data::fill(output, false);

          mln_piter(I) p(input.domain());
          mln_niter(N) n(nbh, p);
          for_all(p)
            if (input(p) == true)
              {
                for_all(n) if (input.has(n))
                  if (input(n) == false)
                    {
                      output(p) = true;
                      break;
                    }
              }
            else // input(p) == false
              {
                for_all(n) if (input.has(n))
                  if (input(n) == true)
                    {
                      output(p) = true;
                      break;
                    }
              }

          trace::exiting("morpho::elementary::impl::gradient_on_set");
          return output;
        }


        template <typename I, typename N>
        mln_concrete(I)
        gradient_on_function_fastest(const Image<I>& input_, const Neighborhood<N>& nbh_)
        {
          trace::entering("morpho::elementary::impl::gradient_on_function_fastest");

          const I& input = exact(input_);
          const N& nbh   = exact(nbh_);
          internal::gradient_tests(input, nbh);

          accu::stat::min_max<mln_value(I)> a;
          extension::adjust_duplicate(input, nbh);

          typedef mln_concrete(I) O;
          O output;
          initialize(output, input);

          mln_pixter(const I) p_in(input);
          mln_pixter(O) p_out(output);
          mln_nixter(const I, N) n(p_in, nbh);
          for_all_2(p_in, p_out)
            {
              a.take_as_init(p_in.val());
              for_all(n)
                a.take(n.val());
              p_out.val() = a.second() - a.first();
            }

          trace::exiting("morpho::elementary::impl::gradient_on_function_fastest");
          return output;
        }

      } // end of namespace mln::morpho::elementary::impl


      namespace internal
      {

        // Dispatch.

        template <typename I, typename N>
        mln_concrete(I)
        gradient_dispatch(trait::image::kind::any,
                          trait::image::speed::any,
                          const Image<I>& input, const Neighborhood<N>& nbh)
        {
          return impl::gradient_on_function(input, nbh);
        }

        template <typename I, typename N>
        mln_concrete(I)
        gradient_dispatch(trait::image::kind::any,
                          trait::image::speed::fastest,
                          const Image<I>& input, const Neighborhood<N>& nbh)
        {
          return impl::gradient_on_function_fastest(input, nbh);
        }

        template <typename I, typename N>
        mln_concrete(I)
        gradient_dispatch(trait::image::kind::logic,
                          trait::image::speed::any,
                          const Image<I>& input, const Neighborhood<N>& nbh)
        {
          return impl::gradient_on_set(input, nbh);
        }

        // May be redundant with the previous version but fixes an ambiguity
        // with image*d<bool> which is fasted AND logic.
        template <typename I, typename N>
        mln_concrete(I)
        gradient_dispatch(trait::image::kind::logic,
                          trait::image::speed::fastest,
                          const Image<I>& input, const Neighborhood<N>& nbh)
        {
          return impl::gradient_on_set(input, nbh);
        }

        template <typename I, typename N>
        mln_concrete(I)
        gradient_dispatch(const Image<I>& input, const Neighborhood<N>& nbh)
        {
          return gradient_dispatch(mln_trait_image_kind(I)(),
                                   mln_trait_image_speed(I)(),
                                   input, nbh);
        }

      } // end of namespace mln::morpho::elementary::internal


      // Facade.

      template <typename I, typename N>
      mln_concrete(I)
        gradient(const Image<I>& input, const Neighborhood<N>& nbh)
      {
        trace::entering("morpho::elementary::gradient");

        internal::gradient_tests(input, nbh);
        mln_concrete(I) output = internal::gradient_dispatch(input, nbh);
        
        trace::exiting("morpho::elementary::gradient");
        return output;
      }

# endif // ! MLN_INCLUDE_ONLY

    } // end of namespace mln::morpho::elementary

  } // end of namespace mln::morpho

} // end of namespace mln


#endif // ! MLN_MORPHO_ELEMENTARY_GRADIENT_HH