Chris@102: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@102: 
Chris@102: // Copyright (c) 2012-2014 Barend Gehrels, Amsterdam, the Netherlands.
Chris@102: 
Chris@102: // Use, modification and distribution is subject to the Boost Software License,
Chris@102: // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@102: // http://www.boost.org/LICENSE_1_0.txt)
Chris@102: 
Chris@102: #ifndef BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_HPP
Chris@102: #define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_HPP
Chris@102: 
Chris@102: namespace boost { namespace geometry
Chris@102: {
Chris@102: 
Chris@102: namespace strategy { namespace buffer
Chris@102: {
Chris@102: 
Chris@102: /*
Chris@102: 
Chris@102:    A Buffer-join strategy gets 4 input points.
Chris@102:    On the two consecutive segments s1 and s2 (joining at vertex v):
Chris@102: 
Chris@102:    The lines from parallel at s1, s2 (at buffer-distance) end/start
Chris@102:    in two points perpendicular to the segments: p1 and p2.
Chris@102:    These parallel lines interesct in point ip
Chris@102: 
Chris@102:              (s2)
Chris@102:               |
Chris@102:               |
Chris@102:               ^
Chris@102:               |
Chris@102:         (p2)  |(v)
Chris@102:         *     +----<--- (s1)
Chris@102: 
Chris@102:         x(ip) *(p1)
Chris@102: 
Chris@102: 
Chris@102:     So, in clockwise order:
Chris@102:         v : vertex point
Chris@102:         p1: perpendicular on left side of segment1<1> (perp1)
Chris@102:         ip: intersection point
Chris@102:         p2: perpendicular on left side of segment2<0> (perp2)
Chris@102: */
Chris@102: 
Chris@102: 
Chris@102: 
Chris@102: /*!
Chris@102: \brief Enumerates options for side of buffer (left/right w.r.t. directed
Chris@102:     segment)
Chris@102: \ingroup enum
Chris@102: \details Around a linestring, a buffer can be defined left or right.
Chris@102:     Around a polygon, assumed clockwise internally,
Chris@102:     a buffer is either on the left side (inflates the polygon), or on the
Chris@102:     right side (deflates the polygon)
Chris@102: */
Chris@102: enum buffer_side_selector { buffer_side_left, buffer_side_right };
Chris@102: 
Chris@102: /*!
Chris@102: \brief Enumerates types of pieces (parts of buffer) around geometries
Chris@102: \ingroup enum
Chris@102: */
Chris@102: enum piece_type
Chris@102: {
Chris@102:     buffered_segment,
Chris@102:     buffered_join,
Chris@102:     buffered_round_end,
Chris@102:     buffered_flat_end,
Chris@102:     buffered_point,
Chris@102:     buffered_concave   // always on the inside
Chris@102: };
Chris@102: 
Chris@102: 
Chris@102: /*!
Chris@102: \brief Enumerates types of joins
Chris@102: \ingroup enum
Chris@102: */
Chris@102: enum join_selector
Chris@102: {
Chris@102:     join_convex,
Chris@102:     join_concave,
Chris@102:     join_continue, // collinear, next segment touches previous segment
Chris@102:     join_spike     // collinear, with overlap, next segment goes back
Chris@102: };
Chris@102: 
Chris@102: 
Chris@102: }} // namespace strategy::buffer
Chris@102: 
Chris@102: 
Chris@102: }} // namespace boost::geometry
Chris@102: 
Chris@102: #endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_HPP