/*
* 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.operation.polygonize;
import java.util.*;
import com.vividsolutions.jts.algorithm.*;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.planargraph.*;
/**
* Represents a ring of {@link PolygonizeDirectedEdge}s which form
* a ring of a polygon. The ring may be either an outer shell or a hole.
*
* @version 1.7
*/
class EdgeRing {
/**
* Find the innermost enclosing shell EdgeRing containing the argument EdgeRing, if any.
* The innermost enclosing ring is the <i>smallest</i> enclosing ring.
* The algorithm used depends on the fact that:
* <br>
* ring A contains ring B iff envelope(ring A) contains envelope(ring B)
* <br>
* This routine is only safe to use if the chosen point of the hole
* is known to be properly contained in a shell
* (which is guaranteed to be the case if the hole does not touch its shell)
*
* @return containing EdgeRing, if there is one
* or null if no containing EdgeRing is found
*/
public static EdgeRing findEdgeRingContaining(EdgeRing testEr, List shellList)
{
LinearRing testRing = testEr.getRing();
Envelope testEnv = testRing.getEnvelopeInternal();
Coordinate testPt = testRing.getCoordinateN(0);
EdgeRing minShell = null;
Envelope minShellEnv = null;
for (Iterator it = shellList.iterator(); it.hasNext(); ) {
EdgeRing tryShell = (EdgeRing) it.next();
LinearRing tryShellRing = tryShell.getRing();
Envelope tryShellEnv = tryShellRing.getEnvelopeInternal();
// the hole envelope cannot equal the shell envelope
// (also guards against testing rings against themselves)
if (tryShellEnv.equals(testEnv)) continue;
// hole must be contained in shell
if (! tryShellEnv.contains(testEnv)) continue;
testPt = CoordinateArrays.ptNotInList(testRing.getCoordinates(), tryShellRing.getCoordinates());
boolean isContained = false;
if (CGAlgorithms.isPointInRing(testPt, tryShellRing.getCoordinates()) )
isContained = true;
// check if this new containing ring is smaller than the current minimum ring
if (isContained) {
if (minShell == null
|| minShellEnv.contains(tryShellEnv)) {
minShell = tryShell;
minShellEnv = minShell.getRing().getEnvelopeInternal();
}
}
}
return minShell;
}
/**
* Finds a point in a list of points which is not contained in another list of points
* @param testPts the {@link Coordinate}s to test
* @param pts an array of {@link Coordinate}s to test the input points against
* @return a {@link Coordinate} from <code>testPts</code> which is not in <code>pts</code>,
* or null if there is no coordinate not in the list
*
* @deprecated Use CoordinateArrays.ptNotInList instead
*/
public static Coordinate ptNotInList(Coordinate[] testPts, Coordinate[] pts)
{
for (int i = 0; i < testPts.length; i++) {
Coordinate testPt = testPts[i];
if (! isInList(testPt, pts))
return testPt;
}
return null;
}
/**
* Tests whether a given point is in an array of points.
* Uses a value-based test.
*
* @param pt a {@link Coordinate} for the test point
* @param pts an array of {@link Coordinate}s to test
* @return <code>true</code> if the point is in the array
*
* @deprecated
*/
public static boolean isInList(Coordinate pt, Coordinate[] pts)
{
for (int i = 0; i < pts.length; i++) {
if (pt.equals(pts[i]))
return true;
}
return false;
}
private GeometryFactory factory;
private List deList = new ArrayList();
// cache the following data for efficiency
private LinearRing ring = null;
private Coordinate[] ringPts = null;
private List holes;
public EdgeRing(GeometryFactory factory)
{
this.factory = factory;
}
/**
* Adds a {@link DirectedEdge} which is known to form part of this ring.
* @param de the {@link DirectedEdge} to add.
*/
public void add(DirectedEdge de)
{
deList.add(de);
}
/**
* Tests whether this ring is a hole.
* Due to the way the edges in the polyongization graph are linked,
* a ring is a hole if it is oriented counter-clockwise.
* @return <code>true</code> if this ring is a hole
*/
public boolean isHole()
{
LinearRing ring = getRing();
return CGAlgorithms.isCCW(ring.getCoordinates());
}
/**
* Adds a hole to the polygon formed by this ring.
* @param hole the {@link LinearRing} forming the hole.
*/
public void addHole(LinearRing hole) {
if (holes == null)
holes = new ArrayList();
holes.add(hole);
}
/**
* Computes the {@link Polygon} formed by this ring and any contained holes.
*
* @return the {@link Polygon} formed by this ring and its holes.
*/
public Polygon getPolygon()
{
LinearRing[] holeLR = null;
if (holes != null) {
holeLR = new LinearRing[holes.size()];
for (int i = 0; i < holes.size(); i++) {
holeLR[i] = (LinearRing) holes.get(i);
}
}
Polygon poly = factory.createPolygon(ring, holeLR);
return poly;
}
/**
* Tests if the {@link LinearRing} ring formed by this edge ring is topologically valid.
*
* @return true if the ring is valid
*/
public boolean isValid()
{
getCoordinates();
if (ringPts.length <= 3) return false;
getRing();
return ring.isValid();
}
/**
* Computes the list of coordinates which are contained in this ring.
* The coordinatea are computed once only and cached.
*
* @return an array of the {@link Coordinate}s in this ring
*/
private Coordinate[] getCoordinates()
{
if (ringPts == null) {
CoordinateList coordList = new CoordinateList();
for (Iterator i = deList.iterator(); i.hasNext(); ) {
DirectedEdge de = (DirectedEdge) i.next();
PolygonizeEdge edge = (PolygonizeEdge) de.getEdge();
addEdge(edge.getLine().getCoordinates(), de.getEdgeDirection(), coordList);
}
ringPts = coordList.toCoordinateArray();
}
return ringPts;
}
/**
* Gets the coordinates for this ring as a {@link LineString}.
* Used to return the coordinates in this ring
* as a valid geometry, when it has been detected that the ring is topologically
* invalid.
* @return a {@link LineString} containing the coordinates in this ring
*/
public LineString getLineString()
{
getCoordinates();
return factory.createLineString(ringPts);
}
/**
* Returns this ring as a {@link LinearRing}, or null if an Exception occurs while
* creating it (such as a topology problem). Details of problems are written to
* standard output.
*/
public LinearRing getRing()
{
if (ring != null) return ring;
getCoordinates();
if (ringPts.length < 3) System.out.println(ringPts);
try {
ring = factory.createLinearRing(ringPts);
}
catch (Exception ex) {
System.out.println(ringPts);
}
return ring;
}
private static void addEdge(Coordinate[] coords, boolean isForward, CoordinateList coordList)
{
if (isForward) {
for (int i = 0; i < coords.length; i++) {
coordList.add(coords[i], false);
}
}
else {
for (int i = coords.length - 1; i >= 0; i--) {
coordList.add(coords[i], false);
}
}
}
}