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1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | ||
3 | // Copyright (c) 2012-2014 Barend Gehrels, Amsterdam, the Netherlands. | |
4 | ||
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5 | // This file was modified by Oracle on 2018. |
6 | // Modifications copyright (c) 2018, Oracle and/or its affiliates. | |
7 | ||
8 | // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle | |
9 | ||
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10 | // Use, modification and distribution is subject to the Boost Software License, |
11 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
12 | // http://www.boost.org/LICENSE_1_0.txt) | |
13 | ||
14 | #ifndef BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_END_FLAT_HPP | |
15 | #define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_END_FLAT_HPP | |
16 | ||
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17 | #include <boost/geometry/core/coordinate_type.hpp> |
18 | #include <boost/geometry/strategies/buffer.hpp> | |
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19 | #include <boost/geometry/strategies/tags.hpp> |
20 | #include <boost/geometry/strategies/side.hpp> | |
21 | #include <boost/geometry/util/math.hpp> | |
22 | #include <boost/geometry/util/select_most_precise.hpp> | |
23 | ||
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24 | namespace boost { namespace geometry |
25 | { | |
26 | ||
27 | ||
28 | namespace strategy { namespace buffer | |
29 | { | |
30 | ||
31 | ||
32 | /*! | |
33 | \brief Let the buffer create flat ends | |
34 | \ingroup strategies | |
35 | \details This strategy can be used as EndStrategy for the buffer algorithm. | |
36 | It creates a flat end for each linestring-end. It can be applied | |
37 | for (multi)linestrings. Also it is applicable for spikes in (multi)polygons. | |
38 | This strategy is only applicable for Cartesian coordinate systems. | |
39 | ||
40 | \qbk{ | |
41 | [heading Example] | |
42 | [buffer_end_flat] | |
43 | [heading Output] | |
44 | [$img/strategies/buffer_end_flat.png] | |
45 | [heading See also] | |
46 | \* [link geometry.reference.algorithms.buffer.buffer_7_with_strategies buffer (with strategies)] | |
47 | \* [link geometry.reference.strategies.strategy_buffer_end_round end_round] | |
48 | } | |
49 | */ | |
50 | class end_flat | |
51 | { | |
52 | ||
53 | public : | |
54 | ||
55 | #ifndef DOXYGEN_SHOULD_SKIP_THIS | |
56 | //! Fills output_range with a flat end | |
57 | template <typename Point, typename RangeOut, typename DistanceStrategy> | |
58 | inline void apply(Point const& penultimate_point, | |
59 | Point const& perp_left_point, | |
60 | Point const& ultimate_point, | |
61 | Point const& perp_right_point, | |
62 | buffer_side_selector side, | |
63 | DistanceStrategy const& distance, | |
64 | RangeOut& range_out) const | |
65 | { | |
66 | typedef typename coordinate_type<Point>::type coordinate_type; | |
67 | ||
68 | typedef typename geometry::select_most_precise | |
69 | < | |
70 | coordinate_type, | |
71 | double | |
72 | >::type promoted_type; | |
73 | ||
74 | promoted_type const dist_left = distance.apply(penultimate_point, ultimate_point, buffer_side_left); | |
75 | promoted_type const dist_right = distance.apply(penultimate_point, ultimate_point, buffer_side_right); | |
76 | ||
77 | bool reversed = (side == buffer_side_left && dist_right < 0 && -dist_right > dist_left) | |
78 | || (side == buffer_side_right && dist_left < 0 && -dist_left > dist_right) | |
79 | ; | |
80 | if (reversed) | |
81 | { | |
82 | range_out.push_back(perp_right_point); | |
83 | range_out.push_back(perp_left_point); | |
84 | } | |
85 | else | |
86 | { | |
87 | range_out.push_back(perp_left_point); | |
88 | range_out.push_back(perp_right_point); | |
89 | } | |
90 | // Don't add the ultimate_point (endpoint of the linestring). | |
91 | // The buffer might be generated completely at one side. | |
92 | // In other cases it does no harm but is further useless | |
93 | } | |
94 | ||
95 | template <typename NumericType> | |
96 | static inline NumericType max_distance(NumericType const& distance) | |
97 | { | |
98 | return distance; | |
99 | } | |
100 | ||
101 | //! Returns the piece_type (flat end) | |
102 | static inline piece_type get_piece_type() | |
103 | { | |
104 | return buffered_flat_end; | |
105 | } | |
106 | #endif // DOXYGEN_SHOULD_SKIP_THIS | |
107 | }; | |
108 | ||
109 | ||
110 | }} // namespace strategy::buffer | |
111 | ||
112 | }} // namespace boost::geometry | |
113 | ||
114 | #endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_END_FLAT_HPP |