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