#10640 closed Bugs (fixed)
boost geometry buffer algorithm and counterclockwise polygons
Reported by: | Owned by: | Barend Gehrels | |
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Milestone: | Boost 1.58.0 | Component: | geometry |
Version: | Boost 1.56.0 | Severity: | Problem |
Keywords: | Cc: |
Description
the buffer algorithm does not seem to work (the result multipolygon is always empty) if the input model::polygons are defines as counterclockwise.
test code (adapted from the buffer documentation):
#include <boost/geometry.hpp> #include <boost/geometry/geometries/point_xy.hpp> #include <boost/geometry/geometries/geometries.hpp> int main() { typedef double coordinate_type; typedef boost::geometry::model::d2::point_xy<coordinate_type> point; //counterclockwise typedef boost::geometry::model::polygon<point,false> polygon; const double buffer_distance = 1.0; const int points_per_circle = 36; boost::geometry::strategy::buffer::distance_symmetric<coordinate_type> distance_strategy(buffer_distance); boost::geometry::strategy::buffer::join_round join_strategy(points_per_circle); boost::geometry::strategy::buffer::end_round end_strategy(points_per_circle); boost::geometry::strategy::buffer::point_circle circle_strategy(points_per_circle); boost::geometry::strategy::buffer::side_straight side_strategy; boost::geometry::model::multi_polygon<polygon> result; boost::geometry::model::multi_polygon<polygon> mpol; //points reversed to get a positive area() boost::geometry::read_wkt("MULTIPOLYGON(((0 1,5 3,2 5,0 1)),((1 1,5 0,5 2,1 1)))", mpol); boost::geometry::buffer(mpol.front(), result, distance_strategy, side_strategy, join_strategy, end_strategy, circle_strategy); //always zero std::cerr<<"result size = "<<result.size()<<std::endl; return 0; }
Change History (2)
comment:1 by , 8 years ago
Milestone: | To Be Determined → Boost 1.58.0 |
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Resolution: | → fixed |
Status: | new → closed |
comment:2 by , 7 years ago
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what if they are clock wise?