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JTS Topology Suite 1.14 with additional functions for GeoSpark
/*
* 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;
/**
* Models a constraint segment which can be split in two in various ways,
* according to certain geometric constraints.
*
* @author Martin Davis
*/
public class SplitSegment {
/**
* Computes the {@link Coordinate} that lies a given fraction along the line defined by the
* reverse of the given segment. A fraction of 0.0
returns the end point of the
* segment; a fraction of 1.0
returns the start point of the segment.
*
* @param seg the LineSegment
* @param segmentLengthFraction the fraction of the segment length along the line
* @return the point at that distance
*/
private static Coordinate pointAlongReverse(LineSegment seg, double segmentLengthFraction) {
Coordinate coord = new Coordinate();
coord.x = seg.p1.x - segmentLengthFraction * (seg.p1.x - seg.p0.x);
coord.y = seg.p1.y - segmentLengthFraction * (seg.p1.y - seg.p0.y);
return coord;
}
private LineSegment seg;
private double segLen;
private Coordinate splitPt;
private double minimumLen = 0.0;
public SplitSegment(LineSegment seg) {
this.seg = seg;
segLen = seg.getLength();
}
public void setMinimumLength(double minLen) {
minimumLen = minLen;
}
public Coordinate getSplitPoint() {
return splitPt;
}
public void splitAt(double length, Coordinate endPt) {
double actualLen = getConstrainedLength(length);
double frac = actualLen / segLen;
if (endPt.equals2D(seg.p0))
splitPt = seg.pointAlong(frac);
else
splitPt = pointAlongReverse(seg, frac);
}
public void splitAt(Coordinate pt) {
// check that given pt doesn't violate min length
double minFrac = minimumLen / segLen;
if (pt.distance(seg.p0) < minimumLen) {
splitPt = seg.pointAlong(minFrac);
return;
}
if (pt.distance(seg.p1) < minimumLen) {
splitPt = pointAlongReverse(seg, minFrac);
return;
}
// passes minimum distance check - use provided point as split pt
splitPt = pt;
}
private double getConstrainedLength(double len) {
if (len < minimumLen)
return minimumLen;
return len;
}
}
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