/// <summary>
///
/// </summary>
/// <param name="g"></param>
/// <param name="distance"></param>
/// <returns></returns>
public IGeometry Buffer(IGeometry g, double distance)
{
IPrecisionModel precisionModel = workingPrecisionModel;
if (precisionModel == null)
precisionModel = g.PrecisionModel;
// factory must be the same as the one used by the input
geomFact = g.Factory;
OffsetCurveBuilder curveBuilder = new OffsetCurveBuilder(precisionModel, quadrantSegments);
curveBuilder.EndCapStyle = endCapStyle;
OffsetCurveSetBuilder curveSetBuilder = new OffsetCurveSetBuilder(g, distance, curveBuilder);
IList bufferSegStrList = curveSetBuilder.GetCurves();
// short-circuit test
if (bufferSegStrList.Count <= 0)
{
IGeometry emptyGeom = geomFact.CreateGeometryCollection(new IGeometry[0]);
return emptyGeom;
}
ComputeNodedEdges(bufferSegStrList, precisionModel);
graph = new PlanarGraph(new OverlayNodeFactory());
graph.AddEdges(edgeList.Edges);
IList subgraphList = CreateSubgraphs(graph);
PolygonBuilder polyBuilder = new PolygonBuilder(geomFact);
BuildSubgraphs(subgraphList, polyBuilder);
IList resultPolyList = polyBuilder.Polygons;
IGeometry resultGeom = geomFact.BuildGeometry(resultPolyList);
return resultGeom;
}
/// <summary>
///
/// </summary>
/// <returns></returns>
public bool IsInteriorsConnected()
{
// node the edges, in case holes touch the shell
IList splitEdges = new ArrayList();
geomGraph.ComputeSplitEdges(splitEdges);
// form the edges into rings
PlanarGraph graph = new PlanarGraph(new OverlayNodeFactory());
graph.AddEdges(splitEdges);
SetInteriorEdgesInResult(graph);
graph.LinkResultDirectedEdges();
IList edgeRings = BuildEdgeRings(graph.EdgeEnds);
/*
* Mark all the edges for the edgeRings corresponding to the shells
* of the input polygons. Note only ONE ring gets marked for each shell.
*/
VisitShellInteriors((IGeometry) geomGraph.Geometry, graph);
/*
* If there are any unvisited shell edges
* (i.e. a ring which is not a hole and which has the interior
* of the parent area on the RHS)
* this means that one or more holes must have split the interior of the
* polygon into at least two pieces. The polygon is thus invalid.
*/
return !HasUnvisitedShellEdge(edgeRings);
}
