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/numeric_cast.hpp>
0026 #include <boost/geometry/util/select_most_precise.hpp>
0027
0028
0029 namespace boost { namespace geometry
0030 {
0031
0032 namespace strategy { namespace densify
0033 {
0034
0035
0036 /*!
0037 \brief Densification of cartesian segment.
0038 \ingroup strategies
0039 \tparam CalculationType \tparam_calculation
0040
0041 \qbk{
0042 [heading See also]
0043 [link geometry.reference.algorithms.densify.densify_4_with_strategy densify (with strategy)]
0044 }
0045  */
0046 template
0047 <
0048     typename CalculationType = void
0049 >
0050 class cartesian
0051 {
0052 public:
0053     template <typename Point, typename AssignPolicy, typename T>
0054     static inline void apply(Point const& p0, Point const& p1, AssignPolicy & policy, T const& length_threshold)
0055     {
0056         typedef typename AssignPolicy::point_type out_point_t;
0057         typedef typename coordinate_type<out_point_t>::type out_coord_t;
0058         typedef typename select_most_precise
0059             <
0060                 typename coordinate_type<Point>::type, out_coord_t,
0061                 CalculationType
0062             >::type calc_t;
0063
0064         typedef model::point<calc_t, geometry::dimension<Point>::value, cs::cartesian> calc_point_t;
0065
0066         assert_dimension_equal<calc_point_t, out_point_t>();
0067
0068         calc_point_t cp0, dir01;
0069         // dir01 = p1 - p0
0070         geometry::detail::for_each_dimension<calc_point_t>([&](auto index)
0071         {
0072             calc_t const coord0 = util::numeric_cast<calc_t>(get<index>(p0));
0073             calc_t const coord1 = util::numeric_cast<calc_t>(get<index>(p1));
0074             set<index>(cp0, coord0);
0075             set<index>(dir01, coord1 - coord0);
0076         });
0077
0078         calc_t const dot01 = geometry::dot_product(dir01, dir01);
0079         calc_t const len = math::sqrt(dot01);
0080
0081         BOOST_GEOMETRY_ASSERT(length_threshold > T(0));
0082
0083         signed_size_type const n = signed_size_type(len / length_threshold);
0084         if (n <= 0)
0085         {
0086             return;
0087         }
0088
0089         calc_t const den = calc_t(n + 1);
0090         for (signed_size_type i = 0 ; i < n ; ++i)
0091         {
0092             out_point_t out;
0093
0094             calc_t const num = calc_t(i + 1);
0095             geometry::detail::for_each_dimension<out_point_t>([&](auto index)
0096             {
0097                 // out = p0 + d * dir01
0098                 calc_t const coord = get<index>(cp0) + get<index>(dir01) * num / den;
0099
0100                 set<index>(out, util::numeric_cast<out_coord_t>(coord));
0101             });
0102
0103             policy.apply(out);
0104         }
0105     }
0106 };
0107
0108
0109 #ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
0110 namespace services
0111 {
0112
0113 template <>
0114 struct default_strategy<cartesian_tag>
0115 {
0116     typedef strategy::densify::cartesian<> type;
0117 };
0118
0119
0120 } // namespace services
0121 #endif // DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
0122
0123
0124 }} // namespace strategy::densify
0125
0126
0127 }} // namespace boost::geometry
0128
0129 #endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_DENSIFY_HPP