edu.uci.ics.jung.algorithms.layout

Class SpringLayout<V,E>

java.lang.Object

edu.uci.ics.jung.algorithms.layout.AbstractLayout<V,E>

edu.uci.ics.jung.algorithms.layout.SpringLayout<V,E>

All Implemented Interfaces:

Layout<V,E>, IterativeContext, org.apache.commons.collections15.Transformer<V,java.awt.geom.Point2D>

Direct Known Subclasses:

DAGLayout, SpringLayout2

public class SpringLayout<V,E>
extends AbstractLayout<V,E>
implements IterativeContext

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.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	SpringLayout.SpringDimensionChecker Used for changing the size of the layout in response to a component's size.
protected static class	SpringLayout.SpringVertexData

Field Summary

Fields

Modifier and Type	Field and Description
protected double	force_multiplier
protected org.apache.commons.collections15.Transformer<E,java.lang.Integer>	lengthFunction
protected int	repulsion_range_sq
protected java.util.Map<V,SpringLayout.SpringVertexData>	springVertexData
protected double	stretch

Fields inherited from class edu.uci.ics.jung.algorithms.layout.AbstractLayout

graph, initialized, locations, size

Constructor Summary

Constructors

Constructor and Description
SpringLayout() Creates an instance which does not initialize the vertex locations.
SpringLayout(Graph<V,E> g) Constructor for a SpringLayout for a raw graph with associated dimension--the input knows how big the graph is.
SpringLayout(Graph<V,E> g, org.apache.commons.collections15.Transformer<E,java.lang.Integer> length_function) Constructor for a SpringLayout for a raw graph with associated component.

Method Summary

Modifier and Type	Method and Description
protected void	calculateRepulsion()
boolean	done() For now, we pretend it never finishes.
double	getForceMultiplier() Returns the current value for the edge length force multiplier.
int	getRepulsionRange() Returns the current value for the node repulsion range.
double	getStretch() Returns the current value for the stretch parameter.
void	initialize() Initializes fields in the node that may not have been set during the constructor.
boolean	isIncremental() This one is an incremental visualization
protected void	moveNodes()
protected void	relaxEdges()
void	reset() No effect.
void	setForceMultiplier(double force) Sets the force multiplier for this instance.
void	setRepulsionRange(int range) Sets the node repulsion range (in drawing area units) for this instance.
void	setSize(java.awt.Dimension size) Sets the dimensions of the available space for layout to size.
void	setStretch(double stretch) Sets the stretch parameter for this instance.
void	step() Relaxation step.

Methods inherited from class edu.uci.ics.jung.algorithms.layout.AbstractLayout

getGraph, getSize, getX, getY, isLocked, lock, lock, offsetVertex, setGraph, setInitializer, setLocation, setLocation, transform

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

stretch

protected double stretch

lengthFunction

protected org.apache.commons.collections15.Transformer<E,java.lang.Integer> lengthFunction

repulsion_range_sq

protected int repulsion_range_sq

force_multiplier

protected double force_multiplier

springVertexData

protected java.util.Map<V,SpringLayout.SpringVertexData> springVertexData

Constructor Detail

SpringLayout

public SpringLayout()

Creates an instance which does not initialize the vertex locations.

SpringLayout

public SpringLayout(Graph<V,E> g)

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.

SpringLayout

public SpringLayout(Graph<V,E> g,
                    org.apache.commons.collections15.Transformer<E,java.lang.Integer> length_function)

Constructor for a SpringLayout for a raw graph with associated component.

Parameters:

g - the Graph to lay out

length_function - provides a length for each edge

Method Detail

getStretch

public double getStretch()

Returns the current value for the stretch parameter.

See Also:

setStretch(double)

setSize

public void setSize(java.awt.Dimension size)

Sets the dimensions of the available space for layout to size.

Specified by:

setSize in interface Layout<V,E>

Overrides:

setSize in class AbstractLayout<V,E>

setStretch

public void setStretch(double stretch)

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.

Parameters:

stretch -

getRepulsionRange

public int getRepulsionRange()

Returns the current value for the node repulsion range.

See Also:

setRepulsionRange(int)

setRepulsionRange

public void setRepulsionRange(int range)

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.

Parameters:

range -

getForceMultiplier

public double getForceMultiplier()

Returns the current value for the edge length force multiplier.

See Also:

setForceMultiplier(double)

setForceMultiplier

public void setForceMultiplier(double force)

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.

initialize

public void initialize()

Description copied from interface: Layout

Initializes fields in the node that may not have been set during the constructor. Must be called before the iterations begin.

Specified by:

initialize in interface Layout<V,E>

step

public void step()

Relaxation step. Moves all nodes a smidge.

Specified by:

step in interface IterativeContext

relaxEdges

protected void relaxEdges()

calculateRepulsion

protected void calculateRepulsion()

moveNodes

protected void moveNodes()

isIncremental

public boolean isIncremental()

This one is an incremental visualization

done

public boolean done()

For now, we pretend it never finishes.

Specified by:

done in interface IterativeContext

reset

public void reset()

No effect.

Specified by:

reset in interface Layout<V,E>