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/*
* Copyright (c) 2003, The JUNG Authors
* All rights reserved.
*
* This software is open-source under the BSD license; see either "license.txt"
* or https://github.com/jrtom/jung/blob/master/LICENSE for a description.
*/
package edu.uci.ics.jung.algorithms.layout;
import java.awt.Dimension;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.geom.Point2D;
import java.util.ConcurrentModificationException;
import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import edu.uci.ics.jung.algorithms.layout.util.RandomLocationTransformer;
import edu.uci.ics.jung.algorithms.util.IterativeContext;
import edu.uci.ics.jung.graph.Graph;
import edu.uci.ics.jung.graph.util.Pair;
/**
* The SpringLayout package represents a visualization of a set of nodes. The
* SpringLayout, which is initialized with a Graph, assigns X/Y locations to
* each node. When called relax(), the SpringLayout moves the
* visualization forward one step.
*
* @author Danyel Fisher
* @author Joshua O'Madadhain
*/
public class SpringLayout extends AbstractLayout implements IterativeContext {
protected double stretch = 0.70;
protected Function lengthFunction;
protected int repulsion_range_sq = 100 * 100;
protected double force_multiplier = 1.0 / 3.0;
protected LoadingCache springVertexData =
CacheBuilder.newBuilder().build(new CacheLoader() {
public SpringVertexData load(V vertex) {
return new SpringVertexData();
}
});
// protected Map springVertexData =
// new MapMaker().makeComputingMap(new Function(){
// public SpringVertexData apply(V arg0) {
// return new SpringVertexData();
// }});
/**
* Constructor for a SpringLayout for a raw graph with associated
* dimension--the input knows how big the graph is. Defaults to the unit
* length function.
* @param g the graph on which the layout algorithm is to operate
*/
@SuppressWarnings("unchecked")
public SpringLayout(Graph g) {
this(g, (Function)Functions.constant(30));
}
/**
* Constructor for a SpringLayout for a raw graph with associated component.
*
* @param g the graph on which the layout algorithm is to operate
* @param length_function provides a length for each edge
*/
public SpringLayout(Graph g, Function length_function)
{
super(g);
this.lengthFunction = length_function;
}
/**
* @return the current value for the stretch parameter
*/
public double getStretch() {
return stretch;
}
@Override
public void setSize(Dimension size) {
if(initialized == false)
setInitializer(new RandomLocationTransformer(size));
super.setSize(size);
}
/**
* Sets the stretch parameter for this instance. This value
* specifies how much the degrees of an edge's incident vertices
* should influence how easily the endpoints of that edge
* can move (that is, that edge's tendency to change its length).
*
*
The default value is 0.70. Positive values less than 1 cause
* high-degree vertices to move less than low-degree vertices, and
* values > 1 cause high-degree vertices to move more than
* low-degree vertices. Negative values will have unpredictable
* and inconsistent results.
* @param stretch the stretch parameter
*/
public void setStretch(double stretch) {
this.stretch = stretch;
}
public int getRepulsionRange() {
return (int)(Math.sqrt(repulsion_range_sq));
}
/**
* Sets the node repulsion range (in drawing area units) for this instance.
* Outside this range, nodes do not repel each other. The default value
* is 100. Negative values are treated as their positive equivalents.
* @param range the maximum repulsion range
*/
public void setRepulsionRange(int range) {
this.repulsion_range_sq = range * range;
}
public double getForceMultiplier() {
return force_multiplier;
}
/**
* Sets the force multiplier for this instance. This value is used to
* specify how strongly an edge "wants" to be its default length
* (higher values indicate a greater attraction for the default length),
* which affects how much its endpoints move at each timestep.
* The default value is 1/3. A value of 0 turns off any attempt by the
* layout to cause edges to conform to the default length. Negative
* values cause long edges to get longer and short edges to get shorter; use
* at your own risk.
* @param force an energy field created by all living things that binds the galaxy together
*/
public void setForceMultiplier(double force) {
this.force_multiplier = force;
}
public void initialize() {
}
/**
* Relaxation step. Moves all nodes a smidge.
*/
public void step() {
try {
for(V v : getGraph().getVertices()) {
SpringVertexData svd = springVertexData.getUnchecked(v);
if (svd == null) {
continue;
}
svd.dx /= 4;
svd.dy /= 4;
svd.edgedx = svd.edgedy = 0;
svd.repulsiondx = svd.repulsiondy = 0;
}
} catch(ConcurrentModificationException cme) {
step();
}
relaxEdges();
calculateRepulsion();
moveNodes();
}
protected void relaxEdges() {
try {
for(E e : getGraph().getEdges()) {
Pair endpoints = getGraph().getEndpoints(e);
V v1 = endpoints.getFirst();
V v2 = endpoints.getSecond();
Point2D p1 = apply(v1);
Point2D p2 = apply(v2);
if(p1 == null || p2 == null) continue;
double vx = p1.getX() - p2.getX();
double vy = p1.getY() - p2.getY();
double len = Math.sqrt(vx * vx + vy * vy);
double desiredLen = lengthFunction.apply(e);
// round from zero, if needed [zero would be Bad.].
len = (len == 0) ? .0001 : len;
double f = force_multiplier * (desiredLen - len) / len;
f = f * Math.pow(stretch, (getGraph().degree(v1) + getGraph().degree(v2) - 2));
// the actual movement distance 'dx' is the force multiplied by the
// distance to go.
double dx = f * vx;
double dy = f * vy;
SpringVertexData v1D, v2D;
v1D = springVertexData.getUnchecked(v1);
v2D = springVertexData.getUnchecked(v2);
v1D.edgedx += dx;
v1D.edgedy += dy;
v2D.edgedx += -dx;
v2D.edgedy += -dy;
}
} catch(ConcurrentModificationException cme) {
relaxEdges();
}
}
protected void calculateRepulsion() {
try {
for (V v : getGraph().getVertices()) {
if (isLocked(v)) continue;
SpringVertexData svd = springVertexData.getUnchecked(v);
if(svd == null) continue;
double dx = 0, dy = 0;
for (V v2 : getGraph().getVertices()) {
if (v == v2) continue;
Point2D p = apply(v);
Point2D p2 = apply(v2);
if(p == null || p2 == null) continue;
double vx = p.getX() - p2.getX();
double vy = p.getY() - p2.getY();
double distanceSq = p.distanceSq(p2);
if (distanceSq == 0) {
dx += Math.random();
dy += Math.random();
} else if (distanceSq < repulsion_range_sq) {
double factor = 1;
dx += factor * vx / distanceSq;
dy += factor * vy / distanceSq;
}
}
double dlen = dx * dx + dy * dy;
if (dlen > 0) {
dlen = Math.sqrt(dlen) / 2;
svd.repulsiondx += dx / dlen;
svd.repulsiondy += dy / dlen;
}
}
} catch(ConcurrentModificationException cme) {
calculateRepulsion();
}
}
protected void moveNodes()
{
synchronized (getSize()) {
try {
for (V v : getGraph().getVertices()) {
if (isLocked(v)) continue;
SpringVertexData vd = springVertexData.getUnchecked(v);
if(vd == null) continue;
Point2D xyd = apply(v);
vd.dx += vd.repulsiondx + vd.edgedx;
vd.dy += vd.repulsiondy + vd.edgedy;
// keeps nodes from moving any faster than 5 per time unit
xyd.setLocation(xyd.getX()+Math.max(-5, Math.min(5, vd.dx)),
xyd.getY()+Math.max(-5, Math.min(5, vd.dy)));
Dimension d = getSize();
int width = d.width;
int height = d.height;
if (xyd.getX() < 0) {
xyd.setLocation(0, xyd.getY());
} else if (xyd.getX() > width) {
xyd.setLocation(width, xyd.getY());
}
if (xyd.getY() < 0) {
xyd.setLocation(xyd.getX(), 0);
} else if (xyd.getY() > height) {
xyd.setLocation(xyd.getX(), height);
}
}
} catch(ConcurrentModificationException cme) {
moveNodes();
}
}
}
protected static class SpringVertexData {
protected double edgedx;
protected double edgedy;
protected double repulsiondx;
protected double repulsiondy;
/** movement speed, x */
protected double dx;
/** movement speed, y */
protected double dy;
}
/**
* Used for changing the size of the layout in response to a component's size.
*/
public class SpringDimensionChecker extends ComponentAdapter {
@Override
public void componentResized(ComponentEvent e) {
setSize(e.getComponent().getSize());
}
}
/**
* @return true
*/
public boolean isIncremental() {
return true;
}
/**
* @return false
*/
public boolean done() {
return false;
}
/**
* No effect.
*/
public void reset() {
}
}