/*
* 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.algorithm;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.GeometryCollection;
import org.locationtech.jts.geom.LineString;
/**
* Computes a point in the interior of an linear geometry.
* <h2>Algorithm</h2>
* <ul>
* <li>Find an interior vertex which is closest to
* the centroid of the linestring.
* <li>If there is no interior vertex, find the endpoint which is
* closest to the centroid.
* </ul>
*
* @version 1.7
*/
public class InteriorPointLine {
private Coordinate centroid;
private double minDistance = Double.MAX_VALUE;
private Coordinate interiorPoint = null;
public InteriorPointLine(Geometry g)
{
centroid = g.getCentroid().getCoordinate();
addInterior(g);
if (interiorPoint == null)
addEndpoints(g);
}
public Coordinate getInteriorPoint()
{
return interiorPoint;
}
/**
* Tests the interior vertices (if any)
* defined by a linear Geometry for the best inside point.
* If a Geometry is not of dimension 1 it is not tested.
* @param geom the geometry to add
*/
private void addInterior(Geometry geom)
{
if (geom instanceof LineString) {
addInterior(geom.getCoordinates());
}
else if (geom instanceof GeometryCollection) {
GeometryCollection gc = (GeometryCollection) geom;
for (int i = 0; i < gc.getNumGeometries(); i++) {
addInterior(gc.getGeometryN(i));
}
}
}
private void addInterior(Coordinate[] pts)
{
for (int i = 1; i < pts.length - 1; i++) {
add(pts[i]);
}
}
/**
* Tests the endpoint vertices
* defined by a linear Geometry for the best inside point.
* If a Geometry is not of dimension 1 it is not tested.
* @param geom the geometry to add
*/
private void addEndpoints(Geometry geom)
{
if (geom instanceof LineString) {
addEndpoints(geom.getCoordinates());
}
else if (geom instanceof GeometryCollection) {
GeometryCollection gc = (GeometryCollection) geom;
for (int i = 0; i < gc.getNumGeometries(); i++) {
addEndpoints(gc.getGeometryN(i));
}
}
}
private void addEndpoints(Coordinate[] pts)
{
add(pts[0]);
add(pts[pts.length - 1]);
}
private void add(Coordinate point)
{
double dist = point.distance(centroid);
if (dist < minDistance) {
interiorPoint = new Coordinate(point);
minDistance = dist;
}
}
}