projects / ceph.git / blame
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| 7c673cae FG |
1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
| 2 | ||
| 3 | // Copyright (c) 2012-2014 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_STRATEGIES_CARTESIAN_BUFFER_HPP | |
| 10 | #define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_HPP | |
| 11 | ||
| 12 | namespace boost { namespace geometry | |
| 13 | { | |
| 14 | ||
| 15 | namespace strategy { namespace buffer | |
| 16 | { | |
| 17 | ||
| 18 | /* | |
| 19 | ||
| 20 | A Buffer-join strategy gets 4 input points. | |
| 21 | On the two consecutive segments s1 and s2 (joining at vertex v): | |
| 22 | ||
| 23 | The lines from parallel at s1, s2 (at buffer-distance) end/start | |
| 24 | in two points perpendicular to the segments: p1 and p2. | |
| 25 | These parallel lines interesct in point ip | |
| 26 | ||
| 27 | (s2) | |
| 28 | | | |
| 29 | | | |
| 30 | ^ | |
| 31 | | | |
| 32 | (p2) |(v) | |
| 33 | * +----<--- (s1) | |
| 34 | ||
| 35 | x(ip) *(p1) | |
| 36 | ||
| 37 | ||
| 38 | So, in clockwise order: | |
| 39 | v : vertex point | |
| 40 | p1: perpendicular on left side of segment1<1> (perp1) | |
| 41 | ip: intersection point | |
| 42 | p2: perpendicular on left side of segment2<0> (perp2) | |
| 43 | */ | |
| 44 | ||
| 45 | ||
| 46 | ||
| 47 | /*! | |
| 48 | \brief Enumerates options for side of buffer (left/right w.r.t. directed | |
| 49 | segment) | |
| 50 | \ingroup enum | |
| 51 | \details Around a linestring, a buffer can be defined left or right. | |
| 52 | Around a polygon, assumed clockwise internally, | |
| 53 | a buffer is either on the left side (inflates the polygon), or on the | |
| 54 | right side (deflates the polygon) | |
| 55 | */ | |
| 56 | enum buffer_side_selector { buffer_side_left, buffer_side_right }; | |
| 57 | ||
| 58 | /*! | |
| 59 | \brief Enumerates types of pieces (parts of buffer) around geometries | |
| 60 | \ingroup enum | |
| 61 | */ | |
| 62 | enum piece_type | |
| 63 | { | |
| 64 | buffered_segment, | |
| 65 | buffered_join, | |
| 66 | buffered_round_end, | |
| 67 | buffered_flat_end, | |
| 68 | buffered_point, | |
| 69 | buffered_concave, // always on the inside | |
| 70 | piece_type_unknown | |
| 71 | }; | |
| 72 | ||
| 73 | ||
| 74 | /*! | |
| 75 | \brief Enumerates types of joins | |
| 76 | \ingroup enum | |
| 77 | */ | |
| 78 | enum join_selector | |
| 79 | { | |
| 80 | join_convex, | |
| 81 | join_concave, | |
| 82 | join_continue, // collinear, next segment touches previous segment | |
| 83 | join_spike // collinear, with overlap, next segment goes back | |
| 84 | }; | |
| 85 | ||
| 86 | /*! | |
| 87 | \brief Enumerates types of result codes from buffer strategies | |
| 88 | \ingroup enum | |
| 89 | */ | |
| 90 | enum result_code | |
| 91 | { | |
| 92 | result_normal, | |
| 93 | result_error_numerical, | |
| 94 | result_no_output | |
| 95 | }; | |
| 96 | ||
| 97 | ||
| 98 | }} // namespace strategy::buffer | |
| 99 | ||
| 100 | ||
| 101 | }} // namespace boost::geometry | |
| 102 | ||
| 103 | #endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_HPP |