/*
* 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.geomgraph;
import java.io.PrintStream;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import org.locationtech.jts.geom.Coordinate;
/**
* A list of edge intersections along an {@link Edge}.
* Implements splitting an edge with intersections
* into multiple resultant edges.
*
* @version 1.7
*/
public class EdgeIntersectionList
{
// a Map <EdgeIntersection, EdgeIntersection>
private Map nodeMap = new TreeMap();
Edge edge; // the parent edge
public EdgeIntersectionList(Edge edge)
{
this.edge = edge;
}
/**
* Adds an intersection into the list, if it isn't already there.
* The input segmentIndex and dist are expected to be normalized.
* @return the EdgeIntersection found or added
*/
public EdgeIntersection add(Coordinate intPt, int segmentIndex, double dist)
{
EdgeIntersection eiNew = new EdgeIntersection(intPt, segmentIndex, dist);
EdgeIntersection ei = (EdgeIntersection) nodeMap.get(eiNew);
if (ei != null) {
return ei;
}
nodeMap.put(eiNew, eiNew);
return eiNew;
}
/**
* Returns an iterator of {@link EdgeIntersection}s
*
* @return an Iterator of EdgeIntersections
*/
public Iterator iterator() { return nodeMap.values().iterator(); }
/**
* Tests if the given point is an edge intersection
*
* @param pt the point to test
* @return true if the point is an intersection
*/
public boolean isIntersection(Coordinate pt)
{
for (Iterator it = iterator(); it.hasNext(); ) {
EdgeIntersection ei = (EdgeIntersection) it.next();
if (ei.coord.equals(pt))
return true;
}
return false;
}
/**
* Adds entries for the first and last points of the edge to the list
*/
public void addEndpoints()
{
int maxSegIndex = edge.pts.length - 1;
add(edge.pts[0], 0, 0.0);
add(edge.pts[maxSegIndex], maxSegIndex, 0.0);
}
/**
* Creates new edges for all the edges that the intersections in this
* list split the parent edge into.
* Adds the edges to the input list (this is so a single list
* can be used to accumulate all split edges for a Geometry).
*
* @param edgeList a list of EdgeIntersections
*/
public void addSplitEdges(List edgeList)
{
// ensure that the list has entries for the first and last point of the edge
addEndpoints();
Iterator it = iterator();
// there should always be at least two entries in the list
EdgeIntersection eiPrev = (EdgeIntersection) it.next();
while (it.hasNext()) {
EdgeIntersection ei = (EdgeIntersection) it.next();
Edge newEdge = createSplitEdge(eiPrev, ei);
edgeList.add(newEdge);
eiPrev = ei;
}
}
/**
* Create a new "split edge" with the section of points between
* (and including) the two intersections.
* The label for the new edge is the same as the label for the parent edge.
*/
Edge createSplitEdge(EdgeIntersection ei0, EdgeIntersection ei1)
{
//Debug.print("\ncreateSplitEdge"); Debug.print(ei0); Debug.print(ei1);
int npts = ei1.segmentIndex - ei0.segmentIndex + 2;
Coordinate lastSegStartPt = edge.pts[ei1.segmentIndex];
// if the last intersection point is not equal to the its segment start pt,
// add it to the points list as well.
// (This check is needed because the distance metric is not totally reliable!)
// The check for point equality is 2D only - Z values are ignored
boolean useIntPt1 = ei1.dist > 0.0 || ! ei1.coord.equals2D(lastSegStartPt);
if (! useIntPt1) {
npts--;
}
Coordinate[] pts = new Coordinate[npts];
int ipt = 0;
pts[ipt++] = new Coordinate(ei0.coord);
for (int i = ei0.segmentIndex + 1; i <= ei1.segmentIndex; i++) {
pts[ipt++] = edge.pts[i];
}
if (useIntPt1) pts[ipt] = ei1.coord;
return new Edge(pts, new Label(edge.label));
}
public void print(PrintStream out)
{
out.println("Intersections:");
for (Iterator it = iterator(); it.hasNext(); ) {
EdgeIntersection ei = (EdgeIntersection) it.next();
ei.print(out);
}
}
}