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1 | [/============================================================================ |
2 | Boost.Geometry (aka GGL, Generic Geometry Library) | |
3 | ||
4 | Copyright (c) 2014 Barend Gehrels, Amsterdam, the Netherlands. | |
5 | ||
6 | Use, modification and distribution is subject to the Boost Software License, | |
7 | Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
8 | http://www.boost.org/LICENSE_1_0.txt) | |
9 | =============================================================================/] | |
10 | ||
11 | [def __this_function__ buffer] | |
12 | ||
13 | [heading Strategies] | |
14 | The 5 strategies give the user control to the generated buffer | |
15 | ||
16 | * convex corners can be rounded or sharp | |
17 | * line-ends can be rounded or flat | |
18 | * distance can be symmetric or assymetric, and positive or negative | |
19 | * around points the shape can be circular or square | |
20 | * the sides can be controlled (currently there is only one option provided) | |
21 | ||
22 | By specifying a negative distance for the distance_strategy, for the (multi) polygon case, the polygon will be smaller (also known as deflate). The distance cannot be 0. | |
23 | ||
24 | The next figure shows where in the generated buffer the strategies have effect | |
25 | ||
26 | [$img/algorithms/buffer_strategies.png] | |
27 | ||
28 | [heading_conformance_ogc __this_function__..Buffer] | |
29 | It is conformant if used with the following combination of strategies: | |
30 | [link geometry.reference.strategies.strategy_buffer_join_round join_round], | |
31 | [link geometry.reference.strategies.strategy_buffer_end_round end_round], | |
32 | [link geometry.reference.strategies.strategy_buffer_distance_symmetric distance_symmetric], | |
33 | [link geometry.reference.strategies.strategy_buffer_point_circle point_circle], | |
34 | side_straight | |
35 | ||
36 | [heading Supported geometries] | |
37 | [table | |
38 | [[ ][2D Cartesian]] | |
39 | [[Point][[$img/ok.png]]] | |
40 | [[Segment][[$img/nyi.png]]] | |
41 | [[Box][[$img/nyi.png]]] | |
42 | [[Linestring][[$img/ok.png]]] | |
43 | [[Ring][[$img/ok.png]]] | |
44 | [[Polygon][[$img/ok.png]]] | |
45 | [[MultiPoint][[$img/ok.png]]] | |
46 | [[MultiLinestring][[$img/ok.png]]] | |
47 | [[MultiPolygon][[$img/ok.png]]] | |
48 | ] | |
49 | ||
50 | ||
51 | [heading Examples] | |
52 | [buffer_with_strategies] | |
53 | ||
54 | [heading The linestring case] | |
55 | [$img/algorithms/buffer_linestring.png] | |
56 | ||
57 | [heading The multi_point case] | |
58 | [$img/algorithms/buffer_multi_point.png] | |
59 | ||
60 | [heading The multi_polygon case] | |
61 | [$img/algorithms/buffer_multi_polygon.png] | |
62 | ||
63 | [heading Available Strategies] | |
64 | * JoinStrategy: [link geometry.reference.strategies.strategy_buffer_join_round join_round (cartesian)] | |
65 | * JoinStrategy: [link geometry.reference.strategies.strategy_buffer_join_miter join_miter (cartesian)] | |
66 | * EndStrategy: [link geometry.reference.strategies.strategy_buffer_end_round end_round (cartesian)] | |
67 | * EndStrategy: [link geometry.reference.strategies.strategy_buffer_end_flat end_flat (cartesian)] | |
68 | * DistanceStrategy: [link geometry.reference.strategies.strategy_buffer_distance_symmetric distance_symmetric] | |
69 | * DistanceStrategy: [link geometry.reference.strategies.strategy_buffer_distance_asymmetric distance_asymmetric] | |
70 | * PointStrategy: [link geometry.reference.strategies.strategy_buffer_point_circle point_circle (cartesian)] | |
71 | * PointStrategy: [link geometry.reference.strategies.strategy_buffer_point_square point_square (cartesian)] | |
72 | * SideStrategy: [link geometry.reference.strategies.strategy_buffer_side_straight side_straight (cartesian)] |