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Diffstat (limited to 'boost/geometry/algorithms/detail/get_left_turns.hpp')
| -rw-r--r-- | boost/geometry/algorithms/detail/get_left_turns.hpp | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/boost/geometry/algorithms/detail/get_left_turns.hpp b/boost/geometry/algorithms/detail/get_left_turns.hpp new file mode 100644 index 0000000000..62f0f7f0f4 --- /dev/null +++ b/boost/geometry/algorithms/detail/get_left_turns.hpp @@ -0,0 +1,367 @@ +// Boost.Geometry (aka GGL, Generic Geometry Library) + +// Copyright (c) 2012 Barend Gehrels, Amsterdam, the Netherlands. + +// Use, modification and distribution is subject to the Boost Software License, +// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt) + +#ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_GET_LEFT_TURNS_HPP +#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_GET_LEFT_TURNS_HPP + +#include <boost/geometry/iterators/ever_circling_iterator.hpp> + +namespace boost { namespace geometry +{ + + +#ifndef DOXYGEN_NO_DETAIL +namespace detail +{ + +// TODO: move this to /util/ +template <typename T> +static inline std::pair<T, T> ordered_pair(T const& first, T const& second) +{ + return first < second ? std::make_pair(first, second) : std::make_pair(second, first); +} + +template <typename AngleInfo> +inline void debug_left_turn(AngleInfo const& ai, AngleInfo const& previous) +{ +#ifdef BOOST_GEOMETRY_DEBUG_BUFFER_OCCUPATION + std::cout << "Angle: " << (ai.incoming ? "i" : "o") + << " " << si(ai.seg_id) + << " " << (math::r2d * (ai.angle) ) + << " turn: " << ai.turn_index << "[" << ai.operation_index << "]" + ; + + if (ai.turn_index != previous.turn_index + || ai.operation_index != previous.operation_index) + { + std::cout << " diff: " << math::r2d * math::abs(previous.angle - ai.angle); + } + std::cout << std::endl; +#endif +} + +template <typename AngleInfo> +inline void debug_left_turn(std::string const& caption, AngleInfo const& ai, AngleInfo const& previous, + int code = -99, int code2 = -99, int code3 = -99, int code4 = -99) +{ +#ifdef BOOST_GEOMETRY_DEBUG_BUFFER_OCCUPATION + std::cout << " " << caption + << " turn: " << ai.turn_index << "[" << ai.operation_index << "]" + << " " << si(ai.seg_id) + << " " << (ai.incoming ? "i" : "o") + << " " << (math::r2d * (ai.angle) ) + << " turn: " << previous.turn_index << "[" << previous.operation_index << "]" + << " " << si(previous.seg_id) + << " " << (previous.incoming ? "i" : "o") + << " " << (math::r2d * (previous.angle) ) + ; + + if (code != -99) + { + std::cout << " code: " << code << " , " << code2 << " , " << code3 << " , " << code4; + } + std::cout << std::endl; +#endif +} + + +template <typename Operation> +inline bool include_operation(Operation const& op, + segment_identifier const& outgoing_seg_id, + segment_identifier const& incoming_seg_id) +{ + return op.seg_id == outgoing_seg_id + && op.other_id == incoming_seg_id + && (op.operation == detail::overlay::operation_union + ||op.operation == detail::overlay::operation_continue) + ; +} + +template <typename Turn> +inline bool process_include(segment_identifier const& outgoing_seg_id, segment_identifier const& incoming_seg_id, + int turn_index, Turn& turn, + std::set<int>& keep_indices, int priority) +{ + bool result = false; + for (int i = 0; i < 2; i++) + { + if (include_operation(turn.operations[i], outgoing_seg_id, incoming_seg_id)) + { + turn.operations[i].include_in_occupation_map = true; + if (priority > turn.priority) + { + turn.priority = priority; + } + keep_indices.insert(turn_index); + result = true; + } + } + return result; +} + +template <typename AngleInfo, typename Turns, typename TurnSegmentIndices> +inline bool include_left_turn_of_all( + AngleInfo const& outgoing, AngleInfo const& incoming, + Turns& turns, TurnSegmentIndices const& turn_segment_indices, + std::set<int>& keep_indices, int priority) +{ + segment_identifier const& outgoing_seg_id = turns[outgoing.turn_index].operations[outgoing.operation_index].seg_id; + segment_identifier const& incoming_seg_id = turns[incoming.turn_index].operations[incoming.operation_index].seg_id; + + if (outgoing.turn_index == incoming.turn_index) + { + return process_include(outgoing_seg_id, incoming_seg_id, outgoing.turn_index, turns[outgoing.turn_index], keep_indices, priority); + } + + bool result = false; + std::pair<segment_identifier, segment_identifier> pair = ordered_pair(outgoing_seg_id, incoming_seg_id); + auto it = turn_segment_indices.find(pair); + if (it != turn_segment_indices.end()) + { + for (auto sit = it->second.begin(); sit != it->second.end(); ++sit) + { + if (process_include(outgoing_seg_id, incoming_seg_id, *sit, turns[*sit], keep_indices, priority)) + { + result = true; + } + } + } + return result; +} + +template <std::size_t Index, typename Turn> +inline bool corresponds(Turn const& turn, segment_identifier const& seg_id) +{ + return turn.operations[Index].operation == detail::overlay::operation_union + && turn.operations[Index].seg_id == seg_id; +} + + +template <typename Turns, typename TurnSegmentIndices> +inline bool prefer_by_other(Turns const& turns, + TurnSegmentIndices const& turn_segment_indices, + std::set<int>& indices) +{ + std::map<segment_identifier, int> map; + for (auto sit = indices.begin(); sit != indices.end(); ++sit) + { + map[turns[*sit].operations[0].seg_id]++; + map[turns[*sit].operations[1].seg_id]++; + } + + std::set<segment_identifier> segment_occuring_once; + for (auto mit = map.begin(); mit != map.end(); ++mit) + { + if (mit->second == 1) + { + segment_occuring_once.insert(mit->first); + } +#ifdef BOOST_GEOMETRY_DEBUG_BUFFER_PREFER + std::cout << si(mit->first) << " " << mit->second << std::endl; +#endif + } + + if (segment_occuring_once.size() == 2) + { + // Try to find within all turns a turn with these two segments + + std::set<segment_identifier>::const_iterator soo_it = segment_occuring_once.begin(); + segment_identifier front = *soo_it; + soo_it++; + segment_identifier back = *soo_it; + + std::pair<segment_identifier, segment_identifier> pair = ordered_pair(front, back); + auto it = turn_segment_indices.find(pair); + if (it != turn_segment_indices.end()) + { + // debug_turns_by_indices("Found", it->second); + // Check which is the union/continue + segment_identifier good; + for (auto sit = it->second.begin(); sit != it->second.end(); ++sit) + { + if (turns[*sit].operations[0].operation == detail::overlay::operation_union) + { + good = turns[*sit].operations[0].seg_id; + } + else if (turns[*sit].operations[1].operation == detail::overlay::operation_union) + { + good = turns[*sit].operations[1].seg_id; + } + } + +#ifdef BOOST_GEOMETRY_DEBUG_BUFFER_PREFER + std::cout << "Good: " << si(good) << std::endl; +#endif + + // Find in indexes-to-keep this segment with the union. Discard the other one + std::set<int> ok_indices; + for (auto sit = indices.begin(); sit != indices.end(); ++sit) + { + if (corresponds<0>(turns[*sit], good) || corresponds<1>(turns[*sit], good)) + { + ok_indices.insert(*sit); + } + } + if (ok_indices.size() > 0 && ok_indices.size() < indices.size()) + { + indices = ok_indices; + std::cout << "^"; + return true; + } + } + } + return false; +} + +template <typename Turns> +inline void prefer_by_priority(Turns const& turns, std::set<int>& indices) +{ + // Find max prio + int min_prio = 1024, max_prio = 0; + for (auto sit = indices.begin(); sit != indices.end(); ++sit) + { + if (turns[*sit].priority > max_prio) + { + max_prio = turns[*sit].priority; + } + if (turns[*sit].priority < min_prio) + { + min_prio = turns[*sit].priority; + } + } + + if (min_prio == max_prio) + { + return; + } + + // Only keep indices with high prio + std::set<int> ok_indices; + for (auto sit = indices.begin(); sit != indices.end(); ++sit) + { + if (turns[*sit].priority >= max_prio) + { + ok_indices.insert(*sit); + } + } + if (ok_indices.size() > 0 && ok_indices.size() < indices.size()) + { + indices = ok_indices; + std::cout << "%"; + } +} + +template <typename AngleInfo, typename Angles, typename Turns, typename TurnSegmentIndices> +inline void calculate_left_turns(Angles const& angles, + Turns& turns, TurnSegmentIndices const& turn_segment_indices, + std::set<int>& keep_indices) +{ + bool debug_indicate_size = false; + + typedef typename strategy::side::services::default_strategy + < + typename cs_tag<typename AngleInfo::point_type>::type + >::type side_strategy; + + std::size_t i = 0; + std::size_t n = boost::size(angles); + + typedef geometry::ever_circling_range_iterator<Angles const> circling_iterator; + circling_iterator cit(angles); + + debug_left_turn(*cit, *cit); + for(circling_iterator prev = cit++; i < n; prev = cit++, i++) + { + debug_left_turn(*cit, *prev); + + bool const include = ! geometry::math::equals(prev->angle, cit->angle) + && ! prev->incoming + && cit->incoming; + + if (include) + { + // Go back to possibly include more same left outgoing angles: + // Because we check on side too we can take a large "epsilon" + circling_iterator back = prev - 1; + + typename AngleInfo::angle_type eps = 0.00001; + int b = 1; + for(std::size_t d = 0; + math::abs(prev->angle - back->angle) < eps + && ! back->incoming + && d < n; + d++) + { + --back; + ++b; + } + + // Same but forward to possibly include more incoming angles + int f = 1; + circling_iterator forward = cit + 1; + for(std::size_t d = 0; + math::abs(cit->angle - forward->angle) < eps + && forward->incoming + && d < n; + d++) + { + ++forward; + ++f; + } + +#ifdef BOOST_GEOMETRY_DEBUG_BUFFER_OCCUPATION + std::cout << "HANDLE " << b << "/" << f << " ANGLES" << std::endl; +#endif + for(circling_iterator bit = prev; bit != back; --bit) + { + int code = side_strategy::apply(bit->direction_point, prev->intersection_point, prev->direction_point); + int code2 = side_strategy::apply(prev->direction_point, bit->intersection_point, bit->direction_point); + for(circling_iterator fit = cit; fit != forward; ++fit) + { + int code3 = side_strategy::apply(fit->direction_point, cit->intersection_point, cit->direction_point); + int code4 = side_strategy::apply(cit->direction_point, fit->intersection_point, fit->direction_point); + + int priority = 2; + if (code == -1 && code2 == 1) + { + // This segment is lying right of the other one. + // Cannot ignore it (because of robustness, see a.o. #rt_p21 from unit test). + // But if we find more we can prefer later by priority + // (a.o. necessary for #rt_o2 from unit test) + priority = 1; + } + + bool included = include_left_turn_of_all(*bit, *fit, turns, turn_segment_indices, keep_indices, priority); + debug_left_turn(included ? "KEEP" : "SKIP", *fit, *bit, code, code2, code3, code4); + } + } + } + } + + if (debug_indicate_size) + { + std::cout << " size=" << keep_indices.size(); + } + + if (keep_indices.size() >= 2) + { + prefer_by_other(turns, turn_segment_indices, keep_indices); + } + if (keep_indices.size() >= 2) + { + prefer_by_priority(turns, keep_indices); + } +} + +} // namespace detail +#endif // DOXYGEN_NO_DETAIL + + +}} // namespace boost::geometry + +#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_GET_LEFT_TURNS_HPP |