/*
* Copyright (c) 2016 Vivid Solutions.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
*
* http://www.eclipse.org/org/documents/edl-v10.php.
*/
package org.locationtech.jts.operation.overlay;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.locationtech.jts.algorithm.PointLocator;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.geom.LineString;
import org.locationtech.jts.geomgraph.DirectedEdge;
import org.locationtech.jts.geomgraph.DirectedEdgeStar;
import org.locationtech.jts.geomgraph.Edge;
import org.locationtech.jts.geomgraph.Label;
import org.locationtech.jts.geomgraph.Node;
import org.locationtech.jts.util.Assert;
/**
* Forms JTS LineStrings out of a the graph of {@link DirectedEdge}s
* created by an {@link OverlayOp}.
*
* @version 1.7
*/
public class LineBuilder {
private OverlayOp op;
private GeometryFactory geometryFactory;
private PointLocator ptLocator;
private List lineEdgesList = new ArrayList();
private List resultLineList = new ArrayList();
public LineBuilder(OverlayOp op, GeometryFactory geometryFactory, PointLocator ptLocator) {
this.op = op;
this.geometryFactory = geometryFactory;
this.ptLocator = ptLocator;
}
/**
* @return a list of the LineStrings in the result of the specified overlay operation
*/
public List build(int opCode)
{
findCoveredLineEdges();
collectLines(opCode);
//labelIsolatedLines(lineEdgesList);
buildLines(opCode);
return resultLineList;
}
/**
* Find and mark L edges which are "covered" by the result area (if any).
* L edges at nodes which also have A edges can be checked by checking
* their depth at that node.
* L edges at nodes which do not have A edges can be checked by doing a
* point-in-polygon test with the previously computed result areas.
*/
private void findCoveredLineEdges()
{
// first set covered for all L edges at nodes which have A edges too
for (Iterator nodeit = op.getGraph().getNodes().iterator(); nodeit.hasNext(); ) {
Node node = (Node) nodeit.next();
//node.print(System.out);
((DirectedEdgeStar) node.getEdges()).findCoveredLineEdges();
}
/**
* For all L edges which weren't handled by the above,
* use a point-in-poly test to determine whether they are covered
*/
for (Iterator it = op.getGraph().getEdgeEnds().iterator(); it.hasNext(); ) {
DirectedEdge de = (DirectedEdge) it.next();
Edge e = de.getEdge();
if (de.isLineEdge() && ! e.isCoveredSet()) {
boolean isCovered = op.isCoveredByA(de.getCoordinate());
e.setCovered(isCovered);
}
}
}
private void collectLines(int opCode)
{
for (Iterator it = op.getGraph().getEdgeEnds().iterator(); it.hasNext(); ) {
DirectedEdge de = (DirectedEdge) it.next();
collectLineEdge(de, opCode, lineEdgesList);
collectBoundaryTouchEdge(de, opCode, lineEdgesList);
}
}
/**
* Collect line edges which are in the result.
* Line edges are in the result if they are not part of
* an area boundary, if they are in the result of the overlay operation,
* and if they are not covered by a result area.
*
* @param de the directed edge to test
* @param opCode the overlap operation
* @param edges the list of included line edges
*/
private void collectLineEdge(DirectedEdge de, int opCode, List edges)
{
Label label = de.getLabel();
Edge e = de.getEdge();
// include L edges which are in the result
if (de.isLineEdge()) {
if (! de.isVisited() && OverlayOp.isResultOfOp(label, opCode) && ! e.isCovered()) {
//Debug.println("de: " + de.getLabel());
//Debug.println("edge: " + e.getLabel());
edges.add(e);
de.setVisitedEdge(true);
}
}
}
/**
* Collect edges from Area inputs which should be in the result but
* which have not been included in a result area.
* This happens ONLY:
* <ul>
* <li>during an intersection when the boundaries of two
* areas touch in a line segment
* <li> OR as a result of a dimensional collapse.
* </ul>
*/
private void collectBoundaryTouchEdge(DirectedEdge de, int opCode, List edges)
{
Label label = de.getLabel();
if (de.isLineEdge()) return; // only interested in area edges
if (de.isVisited()) return; // already processed
if (de.isInteriorAreaEdge()) return; // added to handle dimensional collapses
if (de.getEdge().isInResult()) return; // if the edge linework is already included, don't include it again
// sanity check for labelling of result edgerings
Assert.isTrue(! (de.isInResult() || de.getSym().isInResult()) || ! de.getEdge().isInResult());
// include the linework if it's in the result of the operation
if (OverlayOp.isResultOfOp(label, opCode)
&& opCode == OverlayOp.INTERSECTION)
{
edges.add(de.getEdge());
de.setVisitedEdge(true);
}
}
private void buildLines(int opCode)
{
for (Iterator it = lineEdgesList.iterator(); it.hasNext(); ) {
Edge e = (Edge) it.next();
Label label = e.getLabel();
LineString line = geometryFactory.createLineString(e.getCoordinates());
resultLineList.add(line);
e.setInResult(true);
}
}
private void labelIsolatedLines(List edgesList)
{
for (Iterator it = edgesList.iterator(); it.hasNext(); ) {
Edge e = (Edge) it.next();
Label label = e.getLabel();
//n.print(System.out);
if (e.isIsolated()) {
if (label.isNull(0))
labelIsolatedLine(e, 0);
else
labelIsolatedLine(e, 1);
}
}
}
/**
* Label an isolated node with its relationship to the target geometry.
*/
private void labelIsolatedLine(Edge e, int targetIndex)
{
int loc = ptLocator.locate(e.getCoordinate(), op.getArgGeometry(targetIndex));
e.getLabel().setLocation(targetIndex, loc);
}
}