392 lines
12 KiB
C++
392 lines
12 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_GEOMETRY_GEOMETRY_POLICIES_RELATE_DIRECTION_HPP
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#define BOOST_GEOMETRY_GEOMETRY_POLICIES_RELATE_DIRECTION_HPP
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#include <cstddef>
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#include <string>
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#include <boost/concept_check.hpp>
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#include <boost/geometry/arithmetic/determinant.hpp>
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#include <boost/geometry/strategies/side_info.hpp>
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#include <boost/geometry/util/math.hpp>
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#include <boost/geometry/util/select_calculation_type.hpp>
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#include <boost/geometry/util/select_most_precise.hpp>
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namespace boost { namespace geometry
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{
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namespace policies { namespace relate
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{
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struct direction_type
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{
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// NOTE: "char" will be replaced by enum in future version
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inline direction_type(side_info const& s, char h,
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int ha, int hb,
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int da = 0, int db = 0,
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bool op = false)
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: how(h)
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, opposite(op)
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, how_a(ha)
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, how_b(hb)
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, dir_a(da)
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, dir_b(db)
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, sides(s)
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{
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arrival[0] = ha;
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arrival[1] = hb;
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}
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inline direction_type(char h, bool op, int ha = 0, int hb = 0)
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: how(h)
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, opposite(op)
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, how_a(ha)
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, how_b(hb)
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, dir_a(0)
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, dir_b(0)
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{
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arrival[0] = ha;
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arrival[1] = hb;
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}
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// TODO: replace this
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// NOTE: "char" will be replaced by enum in future version
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// "How" is the intersection formed?
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char how;
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// Is it opposite (for collinear/equal cases)
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bool opposite;
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// Information on how A arrives at intersection, how B arrives at intersection
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// 1: arrives at intersection
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// -1: starts from intersection
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int how_a;
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int how_b;
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// Direction: how is A positioned from B
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// 1: points left, seen from IP
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// -1: points right, seen from IP
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// In case of intersection: B's TO direction
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// In case that B's TO direction is at A: B's from direction
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// In collinear cases: it is 0
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int dir_a; // Direction of A-s TO from IP
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int dir_b; // Direction of B-s TO from IP
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// New information
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side_info sides;
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// THIS IS EQUAL TO arrival_a, arrival_b - they probably can go now we have robust fractions
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int arrival[2]; // 1=arrival, -1=departure, 0=neutral; == how_a//how_b
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// About arrival[0] (== arrival of a2 w.r.t. b) for COLLINEAR cases
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// Arrival 1: a1--------->a2 (a arrives within b)
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// b1----->b2
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// Arrival 1: (a in b)
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//
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// Arrival -1: a1--------->a2 (a does not arrive within b)
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// b1----->b2
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// Arrival -1: (b in a) a_1-------------a_2
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// b_1---b_2
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// Arrival 0: a1------->a2 (a arrives at TO-border of b)
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// b1--->b2
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};
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struct segments_direction
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{
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typedef direction_type return_type;
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template
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<
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typename Segment1,
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typename Segment2,
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typename SegmentIntersectionInfo
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>
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static inline return_type segments_crosses(side_info const& sides,
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SegmentIntersectionInfo const& ,
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Segment1 const& , Segment2 const& )
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{
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bool const ra0 = sides.get<0,0>() == 0;
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bool const ra1 = sides.get<0,1>() == 0;
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bool const rb0 = sides.get<1,0>() == 0;
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bool const rb1 = sides.get<1,1>() == 0;
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return
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// opposite and same starting point (FROM)
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ra0 && rb0 ? calculate_side<1>(sides, 'f', -1, -1)
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// opposite and point to each other (TO)
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: ra1 && rb1 ? calculate_side<0>(sides, 't', 1, 1)
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// not opposite, forming an angle, first a then b,
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// directed either both left, or both right
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// Check side of B2 from A. This is not calculated before
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: ra1 && rb0 ? angle<1>(sides, 'a', 1, -1)
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// not opposite, forming a angle, first b then a,
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// directed either both left, or both right
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: ra0 && rb1 ? angle<0>(sides, 'a', -1, 1)
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// b starts from interior of a
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: rb0 ? starts_from_middle(sides, 'B', 0, -1)
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// a starts from interior of b (#39)
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: ra0 ? starts_from_middle(sides, 'A', -1, 0)
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// b ends at interior of a, calculate direction of A from IP
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: rb1 ? b_ends_at_middle(sides)
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// a ends at interior of b
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: ra1 ? a_ends_at_middle(sides)
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// normal intersection
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: calculate_side<1>(sides, 'i', -1, -1)
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;
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}
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template <typename Ratio>
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static inline int arrival_value(Ratio const& r_from, Ratio const& r_to)
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{
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// a1--------->a2
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// b1----->b2
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// a departs: -1
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// a1--------->a2
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// b1----->b2
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// a arrives: 1
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// a1--------->a2
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// b1----->b2
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// both arrive there -> r-to = 1/1, or 0/1 (on_segment)
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// First check the TO (for arrival), then FROM (for departure)
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return r_to.in_segment() ? 1
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: r_to.on_segment() ? 0
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: r_from.on_segment() ? -1
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: -1
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;
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}
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template <typename Ratio>
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static inline void analyze(Ratio const& r,
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int& in_segment_count,
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int& on_end_count,
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int& outside_segment_count)
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{
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if (r.on_end())
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{
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on_end_count++;
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}
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else if (r.in_segment())
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{
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in_segment_count++;
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}
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else
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{
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outside_segment_count++;
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}
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}
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static inline int arrival_from_position_value(int /*v_from*/, int v_to)
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{
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return v_to == 2 ? 1
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: v_to == 1 || v_to == 3 ? 0
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//: v_from >= 1 && v_from <= 3 ? -1
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: -1;
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// NOTE: this should be an equivalent of the above for the other order
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/* (v_from < 3 && v_to > 3) || (v_from > 3 && v_to < 3) ? 1
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: v_from == 3 || v_to == 3 ? 0
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: -1;*/
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}
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static inline void analyse_position_value(int pos_val,
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int & in_segment_count,
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int & on_end_count,
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int & outside_segment_count)
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{
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if ( pos_val == 1 || pos_val == 3 )
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{
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on_end_count++;
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}
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else if ( pos_val == 2 )
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{
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in_segment_count++;
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}
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else
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{
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outside_segment_count++;
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}
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}
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template <typename Segment1, typename Segment2, typename Ratio>
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static inline return_type segments_collinear(
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Segment1 const& , Segment2 const& , bool opposite,
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int a1_wrt_b, int a2_wrt_b, int b1_wrt_a, int b2_wrt_a,
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Ratio const& /*ra_from_wrt_b*/, Ratio const& /*ra_to_wrt_b*/,
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Ratio const& /*rb_from_wrt_a*/, Ratio const& /*rb_to_wrt_a*/)
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{
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return_type r('c', opposite);
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// IMPORTANT: the order of conditions is different as in intersection_points.hpp
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// We assign A in 0 and B in 1
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r.arrival[0] = arrival_from_position_value(a1_wrt_b, a2_wrt_b);
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r.arrival[1] = arrival_from_position_value(b1_wrt_a, b2_wrt_a);
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// Analyse them
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int a_in_segment_count = 0;
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int a_on_end_count = 0;
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int a_outside_segment_count = 0;
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int b_in_segment_count = 0;
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int b_on_end_count = 0;
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int b_outside_segment_count = 0;
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analyse_position_value(a1_wrt_b,
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a_in_segment_count, a_on_end_count, a_outside_segment_count);
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analyse_position_value(a2_wrt_b,
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a_in_segment_count, a_on_end_count, a_outside_segment_count);
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analyse_position_value(b1_wrt_a,
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b_in_segment_count, b_on_end_count, b_outside_segment_count);
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analyse_position_value(b2_wrt_a,
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b_in_segment_count, b_on_end_count, b_outside_segment_count);
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if (a_on_end_count == 1
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&& b_on_end_count == 1
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&& a_outside_segment_count == 1
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&& b_outside_segment_count == 1)
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{
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// This is a collinear touch
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// --------> A (or B)
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// <---------- B (or A)
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// We adapt the "how"
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// TODO: how was to be refactored anyway,
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if (! opposite)
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{
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r.how = 'a';
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}
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else
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{
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r.how = r.arrival[0] == 0 ? 't' : 'f';
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}
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}
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else if (a_on_end_count == 2
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&& b_on_end_count == 2)
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{
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r.how = 'e';
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}
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return r;
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}
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template <typename Segment>
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static inline return_type degenerate(Segment const& , bool)
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{
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return return_type('0', false);
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}
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template <typename Segment, typename Ratio>
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static inline return_type one_degenerate(Segment const& ,
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Ratio const& ,
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bool)
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{
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// To be decided
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return return_type('0', false);
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}
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static inline return_type disjoint()
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{
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return return_type('d', false);
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}
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static inline return_type error(std::string const&)
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{
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// Return "E" to denote error
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// This will throw an error in get_turn_info
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// TODO: change to enum or similar
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return return_type('E', false);
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}
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private :
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template <std::size_t I>
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static inline return_type calculate_side(side_info const& sides,
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char how, int how_a, int how_b)
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{
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int const dir = sides.get<1, I>() == 1 ? 1 : -1;
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return return_type(sides, how, how_a, how_b, -dir, dir);
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}
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template <std::size_t I>
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static inline return_type angle(side_info const& sides,
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char how, int how_a, int how_b)
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{
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int const dir = sides.get<1, I>() == 1 ? 1 : -1;
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return return_type(sides, how, how_a, how_b, dir, dir);
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}
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static inline return_type starts_from_middle(side_info const& sides,
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char which,
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int how_a, int how_b)
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{
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// Calculate ARROW of b segment w.r.t. s1
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int dir = sides.get<1, 1>() == 1 ? 1 : -1;
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// From other perspective, then reverse
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bool const is_a = which == 'A';
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if (is_a)
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{
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dir = -dir;
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}
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return return_type(sides, 's',
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how_a,
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how_b,
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is_a ? dir : -dir,
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! is_a ? dir : -dir);
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}
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// To be harmonized
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static inline return_type a_ends_at_middle(side_info const& sides)
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{
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// Ending at the middle, one ARRIVES, the other one is NEUTRAL
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// (because it both "arrives" and "departs" there)
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int const dir = sides.get<1, 1>() == 1 ? 1 : -1;
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return return_type(sides, 'm', 1, 0, dir, dir);
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}
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static inline return_type b_ends_at_middle(side_info const& sides)
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{
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int const dir = sides.get<0, 1>() == 1 ? 1 : -1;
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return return_type(sides, 'm', 0, 1, dir, dir);
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}
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};
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}} // namespace policies::relate
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_GEOMETRY_POLICIES_RELATE_DIRECTION_HPP
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