/// <summary>
///
/// </summary>
/// <param name="opCode"></param>
private void ComputeOverlay(SpatialFunctions opCode)
{
// copy points from input Geometries.
// This ensures that any Point geometries
// in the input are considered for inclusion in the result set
CopyPoints(0);
CopyPoints(1);
// node the input Geometries
arg[0].ComputeSelfNodes(lineIntersector, false);
arg[1].ComputeSelfNodes(lineIntersector, false);
// compute intersections between edges of the two input geometries
arg[0].ComputeEdgeIntersections(arg[1], lineIntersector, true);
IList baseSplitEdges = new ArrayList();
arg[0].ComputeSplitEdges(baseSplitEdges);
arg[1].ComputeSplitEdges(baseSplitEdges);
// add the noded edges to this result graph
InsertUniqueEdges(baseSplitEdges);
ComputeLabelsFromDepths();
ReplaceCollapsedEdges();
graph.AddEdges(edgeList.Edges);
ComputeLabelling();
LabelIncompleteNodes();
/*
* The ordering of building the result Geometries is important.
* Areas must be built before lines, which must be built before points.
* This is so that lines which are covered by areas are not included
* explicitly, and similarly for points.
*/
FindResultAreaEdges(opCode);
CancelDuplicateResultEdges();
PolygonBuilder polyBuilder = new PolygonBuilder(geomFact);
polyBuilder.Add(graph);
resultPolyList = polyBuilder.Polygons;
LineBuilder lineBuilder = new LineBuilder(this, geomFact, ptLocator);
resultLineList = lineBuilder.Build(opCode);
PointBuilder pointBuilder = new PointBuilder(this, geomFact, ptLocator);
resultPointList = pointBuilder.Build(opCode);
// gather the results from all calculations into a single Geometry for the result set
resultGeom = ComputeGeometry(resultPointList, resultLineList, resultPolyList);
}
/// <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>
/// Completes the building of the input subgraphs by depth-labelling them,
/// and adds them to the <see cref="PolygonBuilder" />.
/// The subgraph list must be sorted in rightmost-coordinate order.
/// </summary>
/// <param name="subgraphList">The subgraphs to build.</param>
/// <param name="polyBuilder">The PolygonBuilder which will build the final polygons.</param>
private void BuildSubgraphs(IList subgraphList, PolygonBuilder polyBuilder)
{
IList processedGraphs = new ArrayList();
foreach(object obj in subgraphList)
{
BufferSubgraph subgraph = (BufferSubgraph)obj;
ICoordinate p = subgraph.RightMostCoordinate;
SubgraphDepthLocater locater = new SubgraphDepthLocater(processedGraphs);
int outsideDepth = locater.GetDepth(p);
subgraph.ComputeDepth(outsideDepth);
subgraph.FindResultEdges();
processedGraphs.Add(subgraph);
polyBuilder.Add(subgraph.DirectedEdges, subgraph.Nodes);
}
}
/// <summary>
///
/// </summary>
/// <param name="opCode"></param>
private void ComputeOverlay(SpatialFunctions opCode)
{
// copy points from input Geometries.
// This ensures that any Point geometries
// in the input are considered for inclusion in the result set
CopyPoints(0);
CopyPoints(1);
// node the input Geometries
arg[0].ComputeSelfNodes(lineIntersector, false);
arg[1].ComputeSelfNodes(lineIntersector, false);
// compute intersections between edges of the two input geometries
arg[0].ComputeEdgeIntersections(arg[1], lineIntersector, true);
IList baseSplitEdges = new ArrayList();
arg[0].ComputeSplitEdges(baseSplitEdges);
arg[1].ComputeSplitEdges(baseSplitEdges);
// add the noded edges to this result graph
InsertUniqueEdges(baseSplitEdges);
ComputeLabelsFromDepths();
ReplaceCollapsedEdges();
graph.AddEdges(edgeList.Edges);
ComputeLabelling();
LabelIncompleteNodes();
/*
* The ordering of building the result Geometries is important.
* Areas must be built before lines, which must be built before points.
* This is so that lines which are covered by areas are not included
* explicitly, and similarly for points.
*/
FindResultAreaEdges(opCode);
CancelDuplicateResultEdges();
PolygonBuilder polyBuilder = new PolygonBuilder(geomFact);
polyBuilder.Add(graph);
resultPolyList = polyBuilder.Polygons;
LineBuilder lineBuilder = new LineBuilder(this, geomFact, ptLocator);
resultLineList = lineBuilder.Build(opCode);
PointBuilder pointBuilder = new PointBuilder(this, geomFact, ptLocator);
resultPointList = pointBuilder.Build(opCode);
// gather the results from all calculations into a single Geometry for the result set
resultGeom = ComputeGeometry(resultPointList, resultLineList, resultPolyList);
}