1 // Boost.Geometry
2
3 // Copyright (c) 2019 Barend Gehrels, Amsterdam, the Netherlands.
4
5 // Use, modification and distribution is subject to the Boost Software License,
6 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
7 // http://www.boost.org/LICENSE_1_0.txt)
8
9 #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_MAKE_MAKE_HPP
10 #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_MAKE_MAKE_HPP
11
12 #include <boost/geometry/geometries/infinite_line.hpp>
13 #include <boost/geometry/core/access.hpp>
14
15 namespace boost { namespace geometry
16 {
17
18 #ifndef DOXYGEN_NO_DETAIL
19 namespace detail { namespace make
20 {
21
22 template <typename Type, typename Coordinate>
23 inline
make_infinite_line(Coordinate const & x1,Coordinate const & y1,Coordinate const & x2,Coordinate const & y2)24 model::infinite_line<Type> make_infinite_line(Coordinate const& x1,
25 Coordinate const& y1, Coordinate const& x2, Coordinate const& y2)
26 {
27 model::infinite_line<Type> result;
28 result.a = y1 - y2;
29 result.b = x2 - x1;
30 result.c = -result.a * x1 - result.b * y1;
31 return result;
32 }
33
34 template <typename Type, typename Point>
35 inline
make_infinite_line(Point const & a,Point const & b)36 model::infinite_line<Type> make_infinite_line(Point const& a, Point const& b)
37 {
38 return make_infinite_line<Type>(geometry::get<0>(a), geometry::get<1>(a),
39 geometry::get<0>(b), geometry::get<1>(b));
40 }
41
42 template <typename Type, typename Segment>
43 inline
make_infinite_line(Segment const & segment)44 model::infinite_line<Type> make_infinite_line(Segment const& segment)
45 {
46 return make_infinite_line<Type>(geometry::get<0, 0>(segment),
47 geometry::get<0, 1>(segment),
48 geometry::get<1, 0>(segment),
49 geometry::get<1, 1>(segment));
50 }
51
52 template <typename Type, typename Point>
53 inline
make_perpendicular_line(Point const & a,Point const & b,Point const & c)54 model::infinite_line<Type> make_perpendicular_line(Point const& a, Point const& b, Point const& c)
55 {
56 // https://www.math-only-math.com/equation-of-a-line-perpendicular-to-a-line.html
57 model::infinite_line<Type> const line = make_infinite_line<Type>(a, b);
58 model::infinite_line<Type> result;
59 result.a = line.b;
60 result.b = -line.a;
61 // Lines with any result.c are perpendicular to a->b
62 // Calculate this result such that it goes through point c
63 result.c = -result.a * geometry::get<0>(c) - result.b * geometry::get<1>(c);
64 return result;
65 }
66
67 }} // namespace detail::make
68 #endif // DOXYGEN_NO_DETAIL
69
70
71 }} // namespace boost::geometry
72
73 #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_MAKE_MAKE_HPP
74