126 lines
4.7 KiB
C++
126 lines
4.7 KiB
C++
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namespace boost { namespace polygon { namespace detail {
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template <typename coordinate_type>
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struct minkowski_offset {
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typedef point_data<coordinate_type> point;
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typedef polygon_set_data<coordinate_type> polygon_set;
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typedef polygon_with_holes_data<coordinate_type> polygon;
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typedef std::pair<point, point> edge;
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static void convolve_two_segments(std::vector<point>& figure, const edge& a, const edge& b) {
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figure.clear();
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figure.push_back(point(a.first));
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figure.push_back(point(a.first));
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figure.push_back(point(a.second));
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figure.push_back(point(a.second));
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convolve(figure[0], b.second);
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convolve(figure[1], b.first);
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convolve(figure[2], b.first);
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convolve(figure[3], b.second);
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}
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template <typename itrT1, typename itrT2>
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static void convolve_two_point_sequences(polygon_set& result, itrT1 ab, itrT1 ae, itrT2 bb, itrT2 be) {
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if(ab == ae || bb == be)
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return;
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// point first_a = *ab; // seems unused
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point prev_a = *ab;
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std::vector<point> vec;
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polygon poly;
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++ab;
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for( ; ab != ae; ++ab) {
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// point first_b = *bb; // seems unused
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point prev_b = *bb;
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itrT2 tmpb = bb;
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++tmpb;
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for( ; tmpb != be; ++tmpb) {
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convolve_two_segments(vec, std::make_pair(prev_b, *tmpb), std::make_pair(prev_a, *ab));
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set_points(poly, vec.begin(), vec.end());
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result.insert(poly);
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prev_b = *tmpb;
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}
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prev_a = *ab;
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}
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}
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template <typename itrT>
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static void convolve_point_sequence_with_polygons(polygon_set& result, itrT b, itrT e, const std::vector<polygon>& polygons) {
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for(std::size_t i = 0; i < polygons.size(); ++i) {
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convolve_two_point_sequences(result, b, e, begin_points(polygons[i]), end_points(polygons[i]));
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for(typename polygon_with_holes_traits<polygon>::iterator_holes_type itrh = begin_holes(polygons[i]);
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itrh != end_holes(polygons[i]); ++itrh) {
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convolve_two_point_sequences(result, b, e, begin_points(*itrh), end_points(*itrh));
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}
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}
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}
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static void convolve_two_polygon_sets(polygon_set& result, const polygon_set& a, const polygon_set& b) {
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result.clear();
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std::vector<polygon> a_polygons;
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std::vector<polygon> b_polygons;
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a.get(a_polygons);
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b.get(b_polygons);
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for(std::size_t ai = 0; ai < a_polygons.size(); ++ai) {
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convolve_point_sequence_with_polygons(result, begin_points(a_polygons[ai]),
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end_points(a_polygons[ai]), b_polygons);
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for(typename polygon_with_holes_traits<polygon>::iterator_holes_type itrh = begin_holes(a_polygons[ai]);
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itrh != end_holes(a_polygons[ai]); ++itrh) {
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convolve_point_sequence_with_polygons(result, begin_points(*itrh),
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end_points(*itrh), b_polygons);
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}
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for(std::size_t bi = 0; bi < b_polygons.size(); ++bi) {
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polygon tmp_poly = a_polygons[ai];
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result.insert(convolve(tmp_poly, *(begin_points(b_polygons[bi]))));
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tmp_poly = b_polygons[bi];
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result.insert(convolve(tmp_poly, *(begin_points(a_polygons[ai]))));
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}
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}
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}
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};
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}
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template<typename T>
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inline polygon_set_data<T>&
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polygon_set_data<T>::resize(coordinate_type resizing, bool corner_fill_arc, unsigned int num_circle_segments) {
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using namespace ::boost::polygon::operators;
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if(!corner_fill_arc) {
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if(resizing < 0)
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return shrink(-resizing);
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if(resizing > 0)
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return bloat(resizing);
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return *this;
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}
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if(resizing == 0) return *this;
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if(empty()) return *this;
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if(num_circle_segments < 3) num_circle_segments = 4;
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rectangle_data<coordinate_type> rect;
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extents(rect);
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if(resizing < 0) {
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::boost::polygon::bloat(rect, 10);
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(*this) = rect - (*this); //invert
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}
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//make_arc(std::vector<point_data< T> >& return_points,
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//point_data< double> start, point_data< double> end,
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//point_data< double> center, double r, unsigned int num_circle_segments)
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std::vector<point_data<coordinate_type> > circle;
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point_data<double> center(0.0, 0.0), start(0.0, (double)resizing);
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make_arc(circle, start, start, center, std::abs((double)resizing),
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num_circle_segments);
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polygon_data<coordinate_type> poly;
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set_points(poly, circle.begin(), circle.end());
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polygon_set_data<coordinate_type> offset_set;
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offset_set += poly;
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polygon_set_data<coordinate_type> result;
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detail::minkowski_offset<coordinate_type>::convolve_two_polygon_sets
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(result, *this, offset_set);
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if(resizing < 0) {
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result = result & rect;//eliminate overhang
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result = result ^ rect;//invert
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}
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*this = result;
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return *this;
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}
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}}
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