public Geometry buffer(Geometry g, double distance) {
PrecisionModel precisionModel = workingPrecisionModel;
if (precisionModel == null) precisionModel = g.getPrecisionModel();
// factory must be the same as the one used by the input
geomFact = g.getFactory();
OffsetCurveBuilder curveBuilder = new OffsetCurveBuilder(precisionModel, bufParams);
OffsetCurveSetBuilder curveSetBuilder = new OffsetCurveSetBuilder(g, distance, curveBuilder);
List bufferSegStrList = curveSetBuilder.getCurves();
// short-circuit test
if (bufferSegStrList.size() <= 0) {
return createEmptyResultGeometry();
}
// BufferDebug.runCount++;
// String filename = "run" + BufferDebug.runCount + "_curves";
// System.out.println("saving " + filename);
// BufferDebug.saveEdges(bufferEdgeList, filename);
// DEBUGGING ONLY
// WKTWriter wktWriter = new WKTWriter();
// Debug.println("Rings: " + wktWriter.write(convertSegStrings(bufferSegStrList.iterator())));
// wktWriter.setMaxCoordinatesPerLine(10);
// System.out.println(wktWriter.writeFormatted(convertSegStrings(bufferSegStrList.iterator())));
computeNodedEdges(bufferSegStrList, precisionModel);
graph = new PlanarGraph(new OverlayNodeFactory());
graph.addEdges(edgeList.getEdges());
List subgraphList = createSubgraphs(graph);
PolygonBuilder polyBuilder = new PolygonBuilder(geomFact);
buildSubgraphs(subgraphList, polyBuilder);
List resultPolyList = polyBuilder.getPolygons();
// just in case...
if (resultPolyList.size() <= 0) {
return createEmptyResultGeometry();
}
Geometry resultGeom = geomFact.buildGeometry(resultPolyList);
return resultGeom;
}
/**
* Because Delete Events have a link to their corresponding Insert event, it is possible to
* compute exactly the range of events which must be compared to a given Insert event object.
*/
private void prepareEvents() {
Collections.sort(events);
for (int i = 0; i < events.size(); i++) {
SweepLineEvent ev = (SweepLineEvent) events.get(i);
if (ev.isDelete()) {
ev.getInsertEvent().setDeleteEventIndex(i);
}
}
}
private void computeIntersections(SegmentIntersector si) {
nOverlaps = 0;
prepareEvents();
for (int i = 0; i < events.size(); i++) {
SweepLineEvent ev = (SweepLineEvent) events.get(i);
if (ev.isInsert()) {
processOverlaps(i, ev.getDeleteEventIndex(), ev, si);
}
}
}