strategies/cartesian/densify.hpp

0001 // Boost.Geometry
0002
0003 // Copyright (c) 2017-2021, Oracle and/or its affiliates.
0004
0005 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0006
0007 // Licensed under the Boost Software License version 1.0.
0008 // http://www.boost.org/users/license.html
0009
0010 #ifndef BOOST_GEOMETRY_STRATEGIES_CARTESIAN_DENSIFY_HPP
0011 #define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_DENSIFY_HPP
0012
0013
0014 #include <boost/geometry/algorithms/detail/convert_point_to_point.hpp>
0015 #include <boost/geometry/algorithms/detail/signed_size_type.hpp>
0016 #include <boost/geometry/arithmetic/arithmetic.hpp>
0017 #include <boost/geometry/arithmetic/dot_product.hpp>
0018 #include <boost/geometry/core/assert.hpp>
0019 #include <boost/geometry/core/coordinate_dimension.hpp>
0020 #include <boost/geometry/core/coordinate_type.hpp>
0021 #include <boost/geometry/geometries/point.hpp>
0022 #include <boost/geometry/strategies/densify.hpp>
0023 #include <boost/geometry/util/algorithm.hpp>
0024 #include <boost/geometry/util/math.hpp>
0025 #include <boost/geometry/util/select_most_precise.hpp>
0026
0027
0028 namespace boost { namespace geometry
0029 {
0030
0031 namespace strategy { namespace densify
0032 {
0033
0034
0035 /*!
0036 \brief Densification of cartesian segment.
0037 \ingroup strategies
0038 \tparam CalculationType \tparam_calculation
0039
0040 \qbk{
0041 [heading See also]
0042 [link geometry.reference.algorithms.densify.densify_4_with_strategy densify (with strategy)]
0043 }
0044  */
0045 template
0046 <
0047     typename CalculationType = void
0048 >
0049 class cartesian
0050 {
0051 public:
0052     template <typename Point, typename AssignPolicy, typename T>
0053     static inline void apply(Point const& p0, Point const& p1, AssignPolicy & policy, T const& length_threshold)
0054     {
0055         typedef typename AssignPolicy::point_type out_point_t;
0056         typedef typename coordinate_type<out_point_t>::type out_coord_t;
0057         typedef typename select_most_precise
0058             <
0059                 typename coordinate_type<Point>::type, out_coord_t,
0060                 CalculationType
0061             >::type calc_t;
0062
0063         typedef model::point<calc_t, geometry::dimension<Point>::value, cs::cartesian> calc_point_t;
0064
0065         assert_dimension_equal<calc_point_t, out_point_t>();
0066
0067         calc_point_t cp0, dir01;
0068         // dir01 = p1 - p0
0069         geometry::detail::for_each_dimension<calc_point_t>([&](auto index)
0070         {
0071             calc_t const coord0 = boost::numeric_cast<calc_t>(get<index>(p0));
0072             calc_t const coord1 = boost::numeric_cast<calc_t>(get<index>(p1));
0073             set<index>(cp0, coord0);
0074             set<index>(dir01, coord1 - coord0);
0075         });
0076
0077         calc_t const dot01 = geometry::dot_product(dir01, dir01);
0078         calc_t const len = math::sqrt(dot01);
0079
0080         BOOST_GEOMETRY_ASSERT(length_threshold > T(0));
0081
0082         signed_size_type const n = signed_size_type(len / length_threshold);
0083         if (n <= 0)
0084         {
0085             return;
0086         }
0087
0088         calc_t const den = calc_t(n + 1);
0089         for (signed_size_type i = 0 ; i < n ; ++i)
0090         {
0091             out_point_t out;
0092
0093             calc_t const num = calc_t(i + 1);
0094             geometry::detail::for_each_dimension<out_point_t>([&](auto index)
0095             {
0096                 // out = p0 + d * dir01
0097                 calc_t const coord = get<index>(cp0) + get<index>(dir01) * num / den;
0098
0099                 set<index>(out, boost::numeric_cast<out_coord_t>(coord));
0100             });
0101
0102             policy.apply(out);
0103         }
0104     }
0105 };
0106
0107
0108 #ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
0109 namespace services
0110 {
0111
0112 template <>
0113 struct default_strategy<cartesian_tag>
0114 {
0115     typedef strategy::densify::cartesian<> type;
0116 };
0117
0118
0119 } // namespace services
0120 #endif // DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
0121
0122
0123 }} // namespace strategy::densify
0124
0125
0126 }} // namespace boost::geometry
0127
0128 #endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_DENSIFY_HPP