ceph/src/boost/libs/geometry/include/boost/geometry/strategies/buffer.hpp

   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