/// <summary>
/// Creates the result of the overlay operation.
/// </summary>
/// <param name="geometry">The geometry.</param>
/// <param name="otherGeometry">The other geometry.</param>
/// <param name="predicate">The overlay predicate.</param>
/// <returns>The result of the overlay.</returns>
private IGeometry CreateResult(IGeometry geometry, IGeometry otherGeometry, Func <IFace, Boolean> predicate)
{
// merge the geometries into a single graph
HalfedgeGraph graph = new HalfedgeGraph(new HalfedgeGraph.FixedIdentifierProvider(1));
graph.MergeGeometry(geometry);
_aIdentifiers = new HashSet <Int32>(graph.Vertices.SelectMany(v => v.Identifiers));
HalfedgeGraph otherGraph = new HalfedgeGraph(new HalfedgeGraph.FixedIdentifierProvider(2));
otherGraph.MergeGeometry(otherGeometry);
_bIdentifiers = new HashSet <Int32>(otherGraph.Vertices.SelectMany(v => v.Identifiers));
graph.MergeGraph(otherGraph);
// query the results
IGeometryFactory factory = _geometryFactory ?? geometry.Factory;
List <IPolygon> result = graph.Faces.Where(predicate).Select(face => face.ToGeometry(factory)).ToList();
if (result.Count == 0)
{
return(null);
}
if (result.Count == 1)
{
return(result[0]);
}
return(factory.CreateGeometryCollection(result));
}
public void HalfedgeGraphMergeGraphTest()
{
// graph A: merging two adjacent and one intersecting polygons
_graph.MergePolygon(_factory.CreatePolygon(
_factory.CreatePoint(0, 0),
_factory.CreatePoint(8, 0),
_factory.CreatePoint(8, 8),
_factory.CreatePoint(0, 8)));
_graph.MergePolygon(_factory.CreatePolygon(
_factory.CreatePoint(8, 0),
_factory.CreatePoint(14, 0),
_factory.CreatePoint(8, 8)));
_graph.MergePolygon(_factory.CreatePolygon(
_factory.CreatePoint(-4, -6),
_factory.CreatePoint(4, -6),
_factory.CreatePoint(4, 2),
_factory.CreatePoint(-4, 2)));
_graph.VerifyTopology();
Assert.AreEqual(4, _graph.Faces.Count());
Assert.AreEqual(14, _graph.Edges.Count());
Assert.AreEqual(28, _graph.Halfedges.Count());
Assert.AreEqual(11, _graph.Vertices.Count());
// graph B: two intersecting polygons
HalfedgeGraph graphB = new HalfedgeGraph();
graphB.MergePolygon(_factory.CreatePolygon(
_factory.CreatePoint(-2, 6),
_factory.CreatePoint(14, 6),
_factory.CreatePoint(4, 14)));
graphB.MergePolygon(_factory.CreatePolygon(
_factory.CreatePoint(2, 1),
_factory.CreatePoint(6, 1),
_factory.CreatePoint(6, 13),
_factory.CreatePoint(2, 13)));
graphB.VerifyTopology();
Assert.AreEqual(7, graphB.Faces.Count());
Assert.AreEqual(19, graphB.Edges.Count());
Assert.AreEqual(38, graphB.Halfedges.Count());
Assert.AreEqual(13, graphB.Vertices.Count());
// graph merge: numerous intersections
_graph.MergeGraph(graphB);
_graph.VerifyTopology();
Assert.AreEqual(17, _graph.Faces.Count());
Assert.AreEqual(47, _graph.Edges.Count());
Assert.AreEqual(94, _graph.Halfedges.Count());
Assert.AreEqual(31, _graph.Vertices.Count());
}
/// <summary>
/// Merges the specified geometries.
/// </summary>
/// <param name="geometry">The geometry.</param>
/// <param name="otherGeometry">The other geometry.</param>
/// <returns>The halfedge graph containing the geometries.</returns>
private void Merge(IGeometry geometry, IGeometry otherGeometry)
{
_graph = new HalfedgeGraph(new HalfedgeGraph.FixedIdentifierProvider(1));
_graph.MergeGeometry(geometry);
_aIdentifiers = new HashSet <Int32>(_graph.Vertices.SelectMany(v => v.Identifiers));
HalfedgeGraph otherGraph = new HalfedgeGraph(new HalfedgeGraph.FixedIdentifierProvider(2));
otherGraph.MergeGeometry(otherGeometry);
_bIdentifiers = new HashSet <Int32>(otherGraph.Vertices.SelectMany(v => v.Identifiers));
_graph.MergeGraph(otherGraph);
}
public void TestInitialize()
{
_graph = new HalfedgeGraph();
}
