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| 1 | /* |
| 2 | * p2d_offset.cpp - Simple offsetting (without dogbones) |
| 3 | * |
| 4 | * Written 2012 by Werner Almesberger |
| 5 | * Copyright 2012 by Werner Almesberger |
| 6 | * |
| 7 | * This library is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | */ |
| 12 | |
| 13 | /* |
| 14 | * References: |
| 15 | * http://www.cgal.org/Manual/latest/examples/Straight_skeleton_2/ |
| 16 | * Create_saop_from_polygon_with_holes_2.cpp |
| 17 | * http://www.cgal.org/Manual/latest/examples/Straight_skeleton_2/print.h |
| 18 | */ |
| 19 | |
| 20 | extern "C" { |
| 21 | #include <assert.h> |
| 22 | |
| 23 | #include "poly2d.h" |
| 24 | } |
| 25 | |
| 26 | #include "cgal_helper.h" |
| 27 | |
| 28 | #include <vector> |
| 29 | #include <boost/shared_ptr.hpp> |
| 30 | |
| 31 | #include <CGAL/Exact_predicates_inexact_constructions_kernel.h> |
| 32 | #include <CGAL/Polygon_with_holes_2.h> |
| 33 | #include <CGAL/create_offset_polygons_from_polygon_with_holes_2.h> |
| 34 | |
| 35 | |
| 36 | typedef CGAL::Exact_predicates_inexact_constructions_kernel K; |
| 37 | |
| 38 | typedef CGAL::Polygon_2<K> Polygon_2; |
| 39 | typedef CGAL::Polygon_with_holes_2<K> Polygon_with_holes; |
| 40 | |
| 41 | typedef boost::shared_ptr<Polygon_2> PolygonPtr; |
| 42 | |
| 43 | typedef std::vector<PolygonPtr> PolygonPtrVector; |
| 44 | |
| 45 | |
| 46 | extern "C" struct p2d *p2d_offset_holes(const struct p2d *p, |
| 47 | const struct p2d *holes, double off) |
| 48 | { |
| 49 | const struct p2d *h; |
| 50 | struct p2d *res = NULL, **last = &res; |
| 51 | |
| 52 | assert(p2d_is_closed(p)); |
| 53 | Polygon_with_holes poly(p2d_to_P2(p, 1)); |
| 54 | |
| 55 | for (h = holes; h; h = h->next) { |
| 56 | assert(p2d_is_closed(h)); |
| 57 | poly.add_hole(p2d_to_P2(h, 0)); |
| 58 | } |
| 59 | |
| 60 | PolygonPtrVector tmp = off > 0 ? |
| 61 | CGAL::create_exterior_skeleton_and_offset_polygons_2(off, |
| 62 | poly.outer_boundary()) : |
| 63 | CGAL::create_interior_skeleton_and_offset_polygons_2(-off, poly); |
| 64 | |
| 65 | for (PolygonPtrVector::const_iterator pit = tmp.begin(); |
| 66 | pit != tmp.end(); ++pit) { |
| 67 | *last = P2_to_p2d(**pit); |
| 68 | last = &(*last)->next; |
| 69 | } |
| 70 | |
| 71 | return res; |
| 72 | } |
| 73 | |
| 74 | |
| 75 | extern "C" struct p2d *p2d_offset(const struct p2d *p, double off) |
| 76 | { |
| 77 | return p2d_offset_holes(p, NULL, off); |
| 78 | } |
| 79 |
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