/*
* The JTS Topology Suite is a collection of Java classes that
* implement the fundamental operations required to validate a given
* geo-spatial data set to a known topological specification.
*
* Copyright (C) 2001 Vivid Solutions
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* For more information, contact:
*
* Vivid Solutions
* Suite #1A
* 2328 Government Street
* Victoria BC V8T 5G5
* Canada
*
* (250)385-6040
* www.vividsolutions.com
*/
package com.vividsolutions.jts.triangulate;
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.LineSegment;
/**
* A strategy for finding constraint split points which attempts to maximise the length of the split
* segments while preventing further encroachment. (This is not always possible for narrow angles).
*
* @author Martin Davis
*/
public class NonEncroachingSplitPointFinder implements ConstraintSplitPointFinder {
public NonEncroachingSplitPointFinder() {}
/**
* A basic strategy for finding split points when nothing extra is known about the geometry of
* the situation.
*
* @param seg the encroached segment
* @param encroachPt the encroaching point
* @return the point at which to split the encroached segment
*/
public Coordinate findSplitPoint(Segment seg, Coordinate encroachPt) {
LineSegment lineSeg = seg.getLineSegment();
double segLen = lineSeg.getLength();
double midPtLen = segLen / 2;
SplitSegment splitSeg = new SplitSegment(lineSeg);
Coordinate projPt = projectedSplitPoint(seg, encroachPt);
/**
* Compute the largest diameter (length) that will produce a split segment which is not
* still encroached upon by the encroaching point (The length is reduced slightly by a
* safety factor)
*/
double nonEncroachDiam = projPt.distance(encroachPt) * 2 * 0.8; // .99;
double maxSplitLen = nonEncroachDiam;
if (maxSplitLen > midPtLen) {
maxSplitLen = midPtLen;
}
splitSeg.setMinimumLength(maxSplitLen);
splitSeg.splitAt(projPt);
return splitSeg.getSplitPoint();
}
/**
* Computes a split point which is the projection of the encroaching point on the segment
*
* @param seg
* @param encroachPt
* @return
*/
public static Coordinate projectedSplitPoint(Segment seg, Coordinate encroachPt) {
LineSegment lineSeg = seg.getLineSegment();
Coordinate projPt = lineSeg.project(encroachPt);
return projPt;
}
}