Chris@16: // Boost.Geometry Index
Chris@16: //
Chris@16: // n-dimensional box's margin value (hypersurface), 2d perimeter, 3d surface, etc...
Chris@16: //
Chris@101: // Copyright (c) 2011-2014 Adam Wulkiewicz, Lodz, Poland.
Chris@16: //
Chris@16: // Use, modification and distribution is subject to the Boost Software License,
Chris@16: // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_MARGIN_HPP
Chris@16: #define BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_MARGIN_HPP
Chris@16: 
Chris@16: // WARNING! comparable_margin() will work only if the same Geometries are compared
Chris@16: // so it shouldn't be used in the case of Variants!
Chris@16: 
Chris@16: namespace boost { namespace geometry { namespace index { namespace detail {
Chris@16: 
Chris@16: template <typename Box>
Chris@16: struct default_margin_result
Chris@16: {
Chris@16:     typedef typename select_most_precise<
Chris@16:         typename coordinate_type<Box>::type,
Chris@16:         long double
Chris@16:     >::type type;
Chris@16: };
Chris@16: 
Chris@101: //template <typename Box,
Chris@101: //          std::size_t CurrentDimension,
Chris@101: //          std::size_t EdgeDimension = dimension<Box>::value>
Chris@16: //struct margin_for_each_edge
Chris@16: //{
Chris@16: //    BOOST_STATIC_ASSERT(0 < CurrentDimension);
Chris@16: //    BOOST_STATIC_ASSERT(0 < EdgeDimension);
Chris@16: //
Chris@16: //    static inline typename default_margin_result<Box>::type apply(Box const& b)
Chris@16: //    {
Chris@16: //        return margin_for_each_edge<Box, CurrentDimension, EdgeDimension - 1>::apply(b) *
Chris@16: //            ( geometry::get<max_corner, EdgeDimension - 1>(b) - geometry::get<min_corner, EdgeDimension - 1>(b) );
Chris@16: //    }
Chris@16: //};
Chris@16: //
Chris@101: //template <typename Box, std::size_t CurrentDimension>
Chris@16: //struct margin_for_each_edge<Box, CurrentDimension, CurrentDimension>
Chris@16: //{
Chris@16: //    BOOST_STATIC_ASSERT(0 < CurrentDimension);
Chris@16: //
Chris@16: //    static inline typename default_margin_result<Box>::type apply(Box const& b)
Chris@16: //    {
Chris@16: //        return margin_for_each_edge<Box, CurrentDimension, CurrentDimension - 1>::apply(b);
Chris@16: //    }
Chris@16: //};
Chris@16: //
Chris@101: //template <typename Box, std::size_t CurrentDimension>
Chris@16: //struct margin_for_each_edge<Box, CurrentDimension, 1>
Chris@16: //{
Chris@16: //    BOOST_STATIC_ASSERT(0 < CurrentDimension);
Chris@16: //
Chris@16: //    static inline typename default_margin_result<Box>::type apply(Box const& b)
Chris@16: //    {
Chris@16: //        return geometry::get<max_corner, 0>(b) - geometry::get<min_corner, 0>(b);
Chris@16: //    }
Chris@16: //};
Chris@16: //
Chris@16: //template <typename Box>
Chris@16: //struct margin_for_each_edge<Box, 1, 1>
Chris@16: //{
Chris@16: //    static inline typename default_margin_result<Box>::type apply(Box const& /*b*/)
Chris@16: //    {
Chris@16: //        return 1;
Chris@16: //    }
Chris@16: //};
Chris@16: //
Chris@101: //template <typename Box,
Chris@101: //          std::size_t CurrentDimension = dimension<Box>::value>
Chris@16: //struct margin_for_each_dimension
Chris@16: //{
Chris@16: //    BOOST_STATIC_ASSERT(0 < CurrentDimension);
Chris@16: //
Chris@16: //    static inline typename default_margin_result<Box>::type apply(Box const& b)
Chris@16: //    {
Chris@16: //        return margin_for_each_dimension<Box, CurrentDimension - 1>::apply(b) +
Chris@101: //            margin_for_each_edge<Box, CurrentDimension>::apply(b);
Chris@16: //    }
Chris@16: //};
Chris@16: //
Chris@16: //template <typename Box>
Chris@16: //struct margin_for_each_dimension<Box, 1>
Chris@16: //{
Chris@16: //    static inline typename default_margin_result<Box>::type apply(Box const& b)
Chris@16: //    {
Chris@101: //        return margin_for_each_edge<Box, 1>::apply(b);
Chris@16: //    }
Chris@16: //};
Chris@16: 
Chris@16: // TODO - test if this definition of margin is ok for Dimension > 2
Chris@16: // Now it's sum of edges lengths
Chris@16: // maybe margin_for_each_dimension should be used to get more or less hypersurface?
Chris@16: 
Chris@101: template <typename Box,
Chris@101:           std::size_t CurrentDimension = dimension<Box>::value>
Chris@16: struct simple_margin_for_each_dimension
Chris@16: {
Chris@16:     BOOST_STATIC_ASSERT(0 < CurrentDimension);
Chris@16: 
Chris@16:     static inline typename default_margin_result<Box>::type apply(Box const& b)
Chris@16:     {
Chris@16:         return simple_margin_for_each_dimension<Box, CurrentDimension - 1>::apply(b) +
Chris@16:             geometry::get<max_corner, CurrentDimension - 1>(b) - geometry::get<min_corner, CurrentDimension - 1>(b);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template <typename Box>
Chris@16: struct simple_margin_for_each_dimension<Box, 1>
Chris@16: {
Chris@16:     static inline typename default_margin_result<Box>::type apply(Box const& b)
Chris@16:     {
Chris@16:         return geometry::get<max_corner, 0>(b) - geometry::get<min_corner, 0>(b);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: namespace dispatch {
Chris@16: 
Chris@16: template <typename Geometry, typename Tag>
Chris@16: struct comparable_margin
Chris@16: {
Chris@16:     BOOST_MPL_ASSERT_MSG(false, NOT_IMPLEMENTED_FOR_THIS_GEOMETRY, (Geometry, Tag));
Chris@16: };
Chris@16: 
Chris@16: template <typename Geometry>
Chris@16: struct comparable_margin<Geometry, point_tag>
Chris@16: {
Chris@16:     typedef typename default_margin_result<Geometry>::type result_type;
Chris@16: 
Chris@16:     static inline result_type apply(Geometry const& ) { return 0; }
Chris@16: };
Chris@16: 
Chris@16: template <typename Box>
Chris@16: struct comparable_margin<Box, box_tag>
Chris@16: {
Chris@16:     typedef typename default_margin_result<Box>::type result_type;
Chris@16: 
Chris@16:     static inline result_type apply(Box const& g)
Chris@16:     {
Chris@101:         //return detail::margin_for_each_dimension<Box>::apply(g);
Chris@101:         return detail::simple_margin_for_each_dimension<Box>::apply(g);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: } // namespace dispatch
Chris@16: 
Chris@16: template <typename Geometry>
Chris@16: typename default_margin_result<Geometry>::type comparable_margin(Geometry const& g)
Chris@16: {
Chris@16:     return dispatch::comparable_margin<
Chris@16:         Geometry,
Chris@16:         typename tag<Geometry>::type
Chris@16:     >::apply(g);
Chris@16: }
Chris@16: 
Chris@16: //template <typename Box>
Chris@16: //typename default_margin_result<Box>::type margin(Box const& b)
Chris@16: //{
Chris@101: //    return 2 * detail::margin_for_each_dimension<Box>::apply(b);
Chris@16: //}
Chris@16: 
Chris@16: }}}} // namespace boost::geometry::index::detail
Chris@16: 
Chris@16: #endif // BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_MARGIN_HPP