/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2001-2006 Vivid Solutions
* (C) 2001-2008, Open Source Geospatial Foundation (OSGeo)
*
* 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;
* version 2.1 of the License.
*
* 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.
*/
package org.geotools.geometry.iso.topograph2D;
import java.io.PrintStream;
/**
* Represents a directed edge in a {@link PlanarGraph}. A DirectedEdge may or
* may not have a reference to a parent {@link Edge} (some applications of
* planar graphs may not require explicit Edge objects to be created). Usually
* a client using a <code>PlanarGraph</code> will subclass <code>DirectedEdge</code>
* to add its own application-specific data and methods.
*
*
*
* @source $URL$
*/
public class DirectedEdge extends EdgeEnd {
/**
* Computes the factor for the change in depth when moving from one location
* to another. E.g. if crossing from the INTERIOR to the EXTERIOR the depth
* decreases, so the factor is -1
*/
public static int depthFactor(int currLocation, int nextLocation) {
if (currLocation == Location.EXTERIOR
&& nextLocation == Location.INTERIOR)
return 1;
else if (currLocation == Location.INTERIOR
&& nextLocation == Location.EXTERIOR)
return -1;
return 0;
}
protected boolean isForward;
private boolean isInResult = false;
private boolean isVisited = false;
private DirectedEdge sym; // the symmetric edge
private DirectedEdge next; // the next edge in the edge ring for the polygon containing this edge
private DirectedEdge nextMin; // the next edge in the MinimalEdgeRing that
// contains this edge
private EdgeRing edgeRing; // the EdgeRing that this edge is part of
private EdgeRing minEdgeRing; // the MinimalEdgeRing that this edge is
// part of
/**
* The depth of each side (position) of this edge. The 0 element of the
* array is never used.
*/
private int[] depth = { 0, -999, -999 };
public DirectedEdge(Edge edge, boolean isForward) {
super(edge);
this.isForward = isForward;
if (isForward) {
init(edge.getCoordinate(0), edge.getCoordinate(1));
} else {
int n = edge.getNumPoints() - 1;
init(edge.getCoordinate(n), edge.getCoordinate(n - 1));
}
computeDirectedLabel();
}
public Edge getEdge() {
return edge;
}
public void setInResult(boolean isInResult) {
this.isInResult = isInResult;
}
public boolean isInResult() {
return isInResult;
}
public boolean isVisited() {
return isVisited;
}
public void setVisited(boolean isVisited) {
this.isVisited = isVisited;
}
public void setEdgeRing(EdgeRing edgeRing) {
this.edgeRing = edgeRing;
}
public EdgeRing getEdgeRing() {
return edgeRing;
}
public void setMinEdgeRing(EdgeRing minEdgeRing) {
this.minEdgeRing = minEdgeRing;
}
public EdgeRing getMinEdgeRing() {
return minEdgeRing;
}
public int getDepth(int position) {
return depth[position];
}
public void setDepth(int position, int depthVal) {
if (depth[position] != -999) {
// if (depth[position] != depthVal) {
// Debug.print(this);
// }
if (depth[position] != depthVal)
throw new TopologyException("assigned depths do not match",
getCoordinate());
// Assert.isTrue(depth[position] == depthVal, "assigned depths do
// not match at " + getCoordinate());
}
depth[position] = depthVal;
}
public int getDepthDelta() {
int depthDelta = edge.getDepthDelta();
if (!isForward)
depthDelta = -depthDelta;
return depthDelta;
}
/**
* setVisitedEdge marks both DirectedEdges attached to a given Edge. This is
* used for edges corresponding to lines, which will only appear oriented in
* a single direction in the result.
*/
public void setVisitedEdge(boolean isVisited) {
setVisited(isVisited);
sym.setVisited(isVisited);
}
/**
* Each Edge gives rise to a pair of symmetric DirectedEdges, in opposite
* directions.
*
* @return the DirectedEdge for the same Edge but in the opposite direction
*/
public DirectedEdge getSym() {
return sym;
}
public boolean isForward() {
return isForward;
}
public void setSym(DirectedEdge de) {
sym = de;
}
public DirectedEdge getNext() {
return next;
}
public void setNext(DirectedEdge next) {
this.next = next;
}
public DirectedEdge getNextMin() {
return nextMin;
}
public void setNextMin(DirectedEdge nextMin) {
this.nextMin = nextMin;
}
/**
* This edge is a line edge if
* <ul>
* <li> at least one of the labels is a line label
* <li> any labels which are not line labels have all Locations = EXTERIOR
* </ul>
*/
public boolean isLineEdge() {
boolean isLine = label.isLine(0) || label.isLine(1);
boolean isExteriorIfArea0 = !label.isArea(0)
|| label.allPositionsEqual(0, Location.EXTERIOR);
boolean isExteriorIfArea1 = !label.isArea(1)
|| label.allPositionsEqual(1, Location.EXTERIOR);
return isLine && isExteriorIfArea0 && isExteriorIfArea1;
}
/**
* This is an interior Area edge if
* <ul>
* <li> its label is an Area label for both Geometries
* <li> and for each Geometry both sides are in the interior.
* </ul>
*
* @return true if this is an interior Area edge
*/
public boolean isInteriorAreaEdge() {
boolean isInteriorAreaEdge = true;
for (int i = 0; i < 2; i++) {
if (!(label.isArea(i)
&& label.getLocation(i, Position.LEFT) == Location.INTERIOR && label
.getLocation(i, Position.RIGHT) == Location.INTERIOR)) {
isInteriorAreaEdge = false;
}
}
return isInteriorAreaEdge;
}
/**
* Compute the label in the appropriate orientation for this DirEdge
*/
private void computeDirectedLabel() {
label = new Label(edge.getLabel());
if (!isForward)
label.flip();
}
/**
* Set both edge depths. One depth for a given side is provided. The other
* is computed depending on the Location transition and the depthDelta of
* the edge.
*/
public void setEdgeDepths(int position, int depth) {
// get the depth transition delta from R to L for this directed Edge
int depthDelta = getEdge().getDepthDelta();
if (!isForward)
depthDelta = -depthDelta;
// if moving from L to R instead of R to L must change sign of delta
int directionFactor = 1;
if (position == Position.LEFT)
directionFactor = -1;
int oppositePos = Position.opposite(position);
int delta = depthDelta * directionFactor;
// TESTINGint delta = depthDelta * DirectedEdge.depthFactor(loc,
// oppositeLoc);
int oppositeDepth = depth + delta;
setDepth(position, depth);
setDepth(oppositePos, oppositeDepth);
}
public void print(PrintStream out) {
super.print(out);
out.print(" " + depth[Position.LEFT] + "/" + depth[Position.RIGHT]);
out.print(" (" + getDepthDelta() + ")");
// out.print(" " + this.hashCode());
// if (next != null) out.print(" next:" + next.hashCode());
if (isInResult)
out.print(" inResult");
}
public void printEdge(PrintStream out) {
print(out);
out.print(" ");
if (isForward)
edge.print(out);
else
edge.printReverse(out);
}
}