giny.util
Class ForceDirectedLayout

java.lang.Object
  giny.util.AbstractLayout
      giny.util.ForceDirectedLayout

public class ForceDirectedLayout

extends AbstractLayout

An implementation of a directed-force layout using logarithmic springs and electrical forces, as discussed in Chapter 10 of the book "Graph Drawing".

However, note that the implementation is a bit different to the equation 10.2 in the book such that:

• Electrical repulsion is subtracted from the force of the spring, since they tend to be opposite forces. The book adds them instead of subtracting.
• The distance between the vertices in the calculation of the electrical repulsion is not squared or multiplied by itself.
• This used logarithimic springs

I am not a mathematician, but the above adjustments to the equation greatly improved the force-directed layout.

Author:

Jesus M. Salvo Jr., Rowan H Christmas

Field Summary

Fields inherited from class giny.util.AbstractLayout

currentSize, graphView, staticNodes

Constructor Summary

ForceDirectedLayout(GraphView g)

Method Summary

void	advancePositions() Relaxation step.
void	doLayout()
boolean	incrementsAreDone() For now, we pretend it never finishes.
protected void	initialize_local_node_view(NodeView v) Initializes the local information on a single vertex.
protected void	initialize_local() Initializes all local information, and is called immediately within the initialize() process.
boolean	isIncremental() This one is an incremental visualization

Methods inherited from class giny.util.AbstractLayout

dontMove, forceMove, getCurrentSize, getNodeView, getStatus, initialize, initializeLocation, initializeLocations, lockNodes, lockVertex, resize, restart, unlockVertex

Methods inherited from class java.lang.Object

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

Constructor Detail

ForceDirectedLayout

public ForceDirectedLayout(GraphView g)

Method Detail

initialize_local

protected void initialize_local()

Description copied from class: AbstractLayout

Initializes all local information, and is called immediately within the initialize() process. The user is responsible for overriding this method to do any construction that may be necessary: for example, to initialize local per-edge or graph-wide data.

Specified by:

initialize_local in class AbstractLayout

initialize_local_node_view

protected void initialize_local_node_view(NodeView v)

Description copied from class: AbstractLayout

Initializes the local information on a single vertex. The user is responsible for overriding this method to do any vertex-level construction that may be necessary: for example, to attach vertex-level information to each vertex.

Specified by:

initialize_local_node_view in class AbstractLayout

doLayout

public void doLayout()

Specified by:

doLayout in class AbstractLayout

isIncremental

public boolean isIncremental()

This one is an incremental visualization

incrementsAreDone

public boolean incrementsAreDone()

For now, we pretend it never finishes.

advancePositions

public void advancePositions()

Relaxation step. Moves all nodes a smidge.

Specified by:

advancePositions in class AbstractLayout

See Also:

Layout#advancePositions()