/*
* 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.snap;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.TopologyException;
import org.locationtech.jts.operation.overlay.OverlayOp;
/**
* Performs an overlay operation using snapping and enhanced precision
* to improve the robustness of the result.
* This class only uses snapping
* if an error is detected when running the standard JTS overlay code.
* Errors detected include thrown exceptions
* (in particular, {@link TopologyException})
* and invalid overlay computations.
*
* @author Martin Davis
* @version 1.7
*/
public class SnapIfNeededOverlayOp
{
public static Geometry overlayOp(Geometry g0, Geometry g1, int opCode)
{
SnapIfNeededOverlayOp op = new SnapIfNeededOverlayOp(g0, g1);
return op.getResultGeometry(opCode);
}
public static Geometry intersection(Geometry g0, Geometry g1)
{
return overlayOp(g0, g1, OverlayOp.INTERSECTION);
}
public static Geometry union(Geometry g0, Geometry g1)
{
return overlayOp(g0, g1, OverlayOp.UNION);
}
public static Geometry difference(Geometry g0, Geometry g1)
{
return overlayOp(g0, g1, OverlayOp.DIFFERENCE);
}
public static Geometry symDifference(Geometry g0, Geometry g1)
{
return overlayOp(g0, g1, OverlayOp.SYMDIFFERENCE);
}
private Geometry[] geom = new Geometry[2];
public SnapIfNeededOverlayOp(Geometry g1, Geometry g2)
{
geom[0] = g1;
geom[1] = g2;
}
public Geometry getResultGeometry(int opCode)
{
Geometry result = null;
boolean isSuccess = false;
RuntimeException savedException = null;
try {
// try basic operation with input geometries
result = OverlayOp.overlayOp(geom[0], geom[1], opCode);
boolean isValid = true;
// not needed if noding validation is used
// boolean isValid = OverlayResultValidator.isValid(geom[0], geom[1], OverlayOp.INTERSECTION, result);
if (isValid)
isSuccess = true;
}
catch (RuntimeException ex) {
savedException = ex;
// ignore this exception, since the operation will be rerun
// System.out.println(ex.getMessage());
// ex.printStackTrace();
//System.out.println(ex.getMessage());
//System.out.println("Geom 0: " + geom[0]);
//System.out.println("Geom 1: " + geom[1]);
}
if (! isSuccess) {
// this may still throw an exception
// if so, throw the original exception since it has the input coordinates
try {
result = SnapOverlayOp.overlayOp(geom[0], geom[1], opCode);
}
catch (RuntimeException ex) {
throw savedException;
}
}
return result;
}
}