/*
* 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.geom.TopologyException;
import org.locationtech.jts.geomgraph.DirectedEdge;
import org.locationtech.jts.geomgraph.DirectedEdgeStar;
import org.locationtech.jts.geomgraph.GeometryGraph;
import org.locationtech.jts.geomgraph.Label;
import org.locationtech.jts.geomgraph.Node;
import org.locationtech.jts.geomgraph.PlanarGraph;
import org.locationtech.jts.geomgraph.Position;
/**
* Tests whether the polygon rings in a {@link GeometryGraph}
* are consistent.
* Used for checking if Topology errors are present after noding.
*
* @author Martin Davis
* @version 1.7
*/
public class ConsistentPolygonRingChecker
{
private PlanarGraph graph;
public ConsistentPolygonRingChecker(PlanarGraph graph) {
this.graph = graph;
}
public void checkAll()
{
check(OverlayOp.INTERSECTION);
check(OverlayOp.DIFFERENCE);
check(OverlayOp.UNION);
check(OverlayOp.SYMDIFFERENCE);
}
/**
* Tests whether the result geometry is consistent
*
* @throws TopologyException if inconsistent topology is found
*/
public void check(int opCode)
{
for (Iterator nodeit = graph.getNodeIterator(); nodeit.hasNext(); ) {
Node node = (Node) nodeit.next();
testLinkResultDirectedEdges((DirectedEdgeStar) node.getEdges(), opCode);
}
}
private List getPotentialResultAreaEdges(DirectedEdgeStar deStar, int opCode)
{
//print(System.out);
List resultAreaEdgeList = new ArrayList();
for (Iterator it = deStar.iterator(); it.hasNext(); ) {
DirectedEdge de = (DirectedEdge) it.next();
if (isPotentialResultAreaEdge(de, opCode) || isPotentialResultAreaEdge(de.getSym(), opCode) )
resultAreaEdgeList.add(de);
}
return resultAreaEdgeList;
}
private boolean isPotentialResultAreaEdge(DirectedEdge de, int opCode)
{
// mark all dirEdges with the appropriate label
Label label = de.getLabel();
if (label.isArea()
&& ! de.isInteriorAreaEdge()
&& OverlayOp.isResultOfOp(
label.getLocation(0, Position.RIGHT),
label.getLocation(1, Position.RIGHT),
opCode)
) {
return true;
//Debug.print("in result "); Debug.println(de);
}
return false;
}
private final int SCANNING_FOR_INCOMING = 1;
private final int LINKING_TO_OUTGOING = 2;
private void testLinkResultDirectedEdges(DirectedEdgeStar deStar, int opCode)
{
// make sure edges are copied to resultAreaEdges list
List ringEdges = getPotentialResultAreaEdges(deStar, opCode);
// find first area edge (if any) to start linking at
DirectedEdge firstOut = null;
DirectedEdge incoming = null;
int state = SCANNING_FOR_INCOMING;
// link edges in CCW order
for (int i = 0; i < ringEdges.size(); i++) {
DirectedEdge nextOut = (DirectedEdge) ringEdges.get(i);
DirectedEdge nextIn = nextOut.getSym();
// skip de's that we're not interested in
if (! nextOut.getLabel().isArea()) continue;
// record first outgoing edge, in order to link the last incoming edge
if (firstOut == null
&& isPotentialResultAreaEdge(nextOut, opCode))
firstOut = nextOut;
// assert: sym.isInResult() == false, since pairs of dirEdges should have been removed already
switch (state) {
case SCANNING_FOR_INCOMING:
if (! isPotentialResultAreaEdge(nextIn, opCode)) continue;
incoming = nextIn;
state = LINKING_TO_OUTGOING;
break;
case LINKING_TO_OUTGOING:
if (! isPotentialResultAreaEdge(nextOut, opCode)) continue;
//incoming.setNext(nextOut);
state = SCANNING_FOR_INCOMING;
break;
}
}
//Debug.print(this);
if (state == LINKING_TO_OUTGOING) {
//Debug.print(firstOut == null, this);
if (firstOut == null)
throw new TopologyException("no outgoing dirEdge found", deStar.getCoordinate());
}
}
}