Function test_graph

generative/triangulation.rs:241–317

()

    #[test]
    fn test_graph() {
        let wkt = b"POINT (65.85186826230156 -39.36525618186133)\n\
                    POINT (61.35756898870892 -34.85194590696902)\n\
                    POINT (38.25507241174806 -24.06029365638358)\n\
                    POINT (9.25896849065506 -63.356505724778266)\n\
                    POINT (-5.692741678486288 -17.181741298068346)\n\
                    POINT (-32.93567551272198 -61.274655097506745)\n";
        let geometries: Vec<_> = read_wkt_geometries(&wkt[..]).collect();
        assert_eq!(geometries.len(), 6);
        let points = flatten_geometries_into_points_ref(geometries.iter());
        let triangulation = triangulate(points).unwrap();

        // NOTE: This all makes much more sense if you draw a picture! Pipe the following through
        // render.py:
        //      cargo test --all-features test_graph -- --nocapture | ./tools/render.py
        #[cfg(feature = "test-io")]
        {
            let lines = triangulation.lines().map(geo::Geometry::Line);
            crate::io::write_wkt_geometries(std::io::stdout(), geometries).unwrap();
            crate::io::write_wkt_geometries(std::io::stdout(), lines).unwrap();
        }

        let triangles = [3, 5, 4, 4, 2, 3, 2, 1, 3, 1, 0, 3];
        assert_eq!(triangulation.triangulation.triangles, triangles);
        let halfedges = [EMPTY, EMPTY, 5, EMPTY, 8, 2, EMPTY, 11, 4, EMPTY, EMPTY, 7];
        assert_eq!(triangulation.triangulation.halfedges, halfedges);

        // NOTE: None of the indices from 'triangles' or 'halfedges' index into 'hull'! You have to
        // create the hull half-edges by looping over the hull. However, be aware that the hull is
        // an open LINESTRING, and needs to be implicitly closed in order to capture the last edge!

        let hull = [1, 0, 3, 5, 4, 2];
        assert_eq!(triangulation.triangulation.hull, hull);

        let graph = triangulation.digraph();
        // It's not necessary that the edges be compared in order, but that's easiest to implement
        // here.
        let edges: Vec<_> = graph
            .raw_edges()
            .iter()
            .map(|e| (e.source().index(), e.target().index()))
            .collect();
        let expected = vec![
            (1, 0),
            (0, 3),
            (3, 5),
            (5, 4),
            (4, 2),
            (2, 1),
            (3, 4),
            (3, 2),
            (4, 3),
            (3, 1),
            (2, 3),
            (1, 3),
        ];
        assert_eq!(edges, expected);