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7ca942d0e9
This broke p2d_is_cw which in turn tripped CGAL::create_interior_skeleton_and_offset_polygons_with_holes_2 with the infamous terminate called after throwing an instance of 'CGAL::Assertion_exception' what(): CGAL ERROR: assertion violation! Expr: lParent File: /usr/include/CGAL/arrange_offset_polygons_2.h Line: 94
poly2d - Yet another 2D polygon library ======================================= Why do we need another 2D polygon library, if there are already CGAL, Boost, Clipper, GPC, ... ? All the above are either written in a weird language, are under a non-Free license, or simply don't provide the feature set we need here. poly2d is written in C, doesn't depend on non-standard libraries, and is licensed under the GPL (will change to LGPL). poly2d serves itself liberally from code already in cameo but provides a simpler and cleaner interface. The first objective is to provide the tools to replace the (badly broken) area filling operation in cameo. Later, poly2d could replace more parts of cameo. poly2d puts more emphasis on simplicity than on performance. Some functions expect closed polygons that don't self-intersect. For now, it doesn't matter whether polygons are clockwise or counter-clockwise. The table below shows the capabilities Open Min. vertices | Concave | | Self-intersect | | | | Y Y Y 0 p2d_contains_poly(b), p2d_copy, p2d_free, p2d_free_all, p2d_is_closed, p2d_no_intersect, p2d_reverse, p2d_vertices, p2d_write_gnuplot, p2d_write_gnuplot_all Y Y Y 1 p2d_read_gnuplot - Y Y 0 p2d_simplify - Y - 3 p2d_is_cw - Y - 3 p2d_contains_point, p2d_contains_poly (a), - Y - 3 p2d_area*, p2d_offset* Not yet implemented: - p2d_simplify (low priority - the offsetting from CGAL already covers the main use case) Not yet specified: - subtraction (do we actually need it ?) Other: - change the license from GPL to LGPL - transform CGAL's idea of outer polygons into something we can use - check for memory leaks Prerequisite: libcgal-dev