ForceDirectedLayout (openjgraph-0.9.2 1.0.0 API)

java.lang.Object
- salvo.jesus.graph.visual.layout.ForceDirectedLayout

All Implemented Interfaces:

Serializable, Runnable, GraphLayoutManager
```
public class ForceDirectedLayout
extends Object
implements GraphLayoutManager, Runnable
```
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.

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor and Description

ForceDirectedLayout(VisualGraph vGraph)

Constructors
Constructor and Description
`ForceDirectedLayout(VisualGraph vGraph)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addEdge(VisualEdge vEdge)` Automatically called when a VisualEdge object has been added to the VisualGraph object being laid out.
`void`	`addFixedVertex(VisualVertex vVertex)` Adds a `VisuaLVertex` that will not be moved from its position during the layout operation of `ForceDirectedLayout`.
`void`	`addVertex(VisualVertex vVertex)` Automatically called when a VisualVertex object has been added to the VisualGraph object being laid out.
`void`	`drawLayout()` This method is called to actually paint or draw the layout of the graph.
`double`	`getEletricalRepulsion()` Returns the eletrical repulsion between all vertices The default value is 400.
`double`	`getIncrement()` Returns the increment by which the vertices gets closer to the equilibrium or closer to the force.
`double`	`getSpringLength()` Returns the desired spring length for all edges.
`double`	`getStiffness()` Returns the stiffness for all edges.
`boolean`	`isInitialized()` Determines if the graph has been initially laid out.
`boolean`	`isVertexFixed(VisualVertex vVertex)` Returns `true` if the specified `VisualVertex` has a fixed position.
`void`	`layout()` This method is called to layout the vertices in the graph, running a thread to perform the layout if the thread is not running, or stopping the thread if the thread is running.
`void`	`paintEdge(Graphics2D g2d, VisualEdge vEdge)`
`void`	`removeEdge(VisualEdge vEdge)` Automatically called when a VisualEdge object is about to be removed from the VisualGraph object being laid out.
`void`	`removeFixedVertex(VisualVertex vVertex)` Removes a `VisualVertex` from the list of `VisualVertices` that has a fixed position.
`void`	`removeVertex(VisualVertex vVertex)` Automatically called when a VisualVertex object is about to be removed from the VisualGraph object being laid out.
`void`	`routeEdge(Graphics2D g2d, VisualEdge vEdge)` Automatically called when a VisualEdge object needs to be drawn.
`void`	`run()`
`void`	`setEletricalRepulsion(double repulsion)` Sets the value of the electrical repulsion between all vertices
`void`	`setIncrement(double increment)` Sets the increment by which the vertices gets close to the equilibrium or gets closer to the direction of the force.
`void`	`setSpringLength(double length)` Sets the desired length of the spring among all edges
`void`	`setStiffness(double stiffness)` Sets the value of stiffness among all edges

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - ForceDirectedLayout
```
public ForceDirectedLayout(VisualGraph vGraph)
```
- Method Detail
  - getSpringLength
```
public double getSpringLength()
```
    Returns the desired spring length for all edges. The default value is 50.
  - getStiffness
```
public double getStiffness()
```
    Returns the stiffness for all edges. The default value is 50.
  - getEletricalRepulsion
```
public double getEletricalRepulsion()
```
    Returns the eletrical repulsion between all vertices The default value is 400.
  - getIncrement
```
public double getIncrement()
```
    Returns the increment by which the vertices gets closer to the equilibrium or closer to the force. The default value is 0.50.
  - setSpringLength
```
public void setSpringLength(double length)
```
    Sets the desired length of the spring among all edges
  - setStiffness
```
public void setStiffness(double stiffness)
```
    Sets the value of stiffness among all edges
  - setEletricalRepulsion
```
public void setEletricalRepulsion(double repulsion)
```
    Sets the value of the electrical repulsion between all vertices
  - setIncrement
```
public void setIncrement(double increment)
```
    Sets the increment by which the vertices gets close to the equilibrium or gets closer to the direction of the force. This must be a number > 0 and <= 1. The higher the value, the faster the layout reaches equilibrium.
  - addFixedVertex
```
public void addFixedVertex(VisualVertex vVertex)
```
    Adds a VisuaLVertex that will not be moved from its position during the layout operation of ForceDirectedLayout.
  - isVertexFixed
```
public boolean isVertexFixed(VisualVertex vVertex)
```
    Returns true if the specified VisualVertex has a fixed position.
  - removeFixedVertex
```
public void removeFixedVertex(VisualVertex vVertex)
```
    Removes a VisualVertex from the list of VisualVertices that has a fixed position.
  - isInitialized
```
public boolean isInitialized()
```
    Determines if the graph has been initially laid out. This method should be called prior to any painting to be done by the graph layout manager, as most internal variables are only initialized during layout.
    
    Specified by:
    
    isInitialized in interface GraphLayoutManager
    
    Returns:
    
    True if the graph has at least been laid out once.
  - paintEdge
```
public void paintEdge(Graphics2D g2d,
                      VisualEdge vEdge)
```
  - routeEdge
```
public void routeEdge(Graphics2D g2d,
                      VisualEdge vEdge)
```
    Description copied from interface: GraphLayoutManager
    
    Automatically called when a VisualEdge object needs to be drawn. This method is typically called from VisualEdgePainterImpl when the VisualGraph encapsulating the VisualEdge has a GraphLayoutManager set. Prior to calling this method, the GeneralPath of the VisualEdge is reset.
    Implementations of this method should set the segments of the VisualEdge's GeneralPath by calling the methods moveTo(), lineTo(), curveTo(), and quadTo().
    
    Specified by:
    
    routeEdge in interface GraphLayoutManager
    
    Parameters:
    
    g2d - The Graphics2D object used for painting
  - layout
```
public void layout()
```
    This method is called to layout the vertices in the graph, running a thread to perform the layout if the thread is not running, or stopping the thread if the thread is running.
    
    Specified by:
    
    layout in interface GraphLayoutManager
  - drawLayout
```
public void drawLayout()
```
    This method is called to actually paint or draw the layout of the graph. This method should only be called after at least one call to layout().
    
    Specified by:
    
    drawLayout in interface GraphLayoutManager
  - addVertex
```
public void addVertex(VisualVertex vVertex)
```
    Description copied from interface: GraphLayoutManager
    
    Automatically called when a VisualVertex object has been added to the VisualGraph object being laid out.
    
    Specified by:
    
    addVertex in interface GraphLayoutManager
    
    Parameters:
    
    vVertex - The newly added VisualVertex object.
  - removeEdge
```
public void removeEdge(VisualEdge vEdge)
```
    Description copied from interface: GraphLayoutManager
    
    Automatically called when a VisualEdge object is about to be removed from the VisualGraph object being laid out.
    
    Specified by:
    
    removeEdge in interface GraphLayoutManager
    
    Parameters:
    
    vEdge - The VisualEdge object to be removed
  - removeVertex
```
public void removeVertex(VisualVertex vVertex)
```
    Description copied from interface: GraphLayoutManager
    
    Automatically called when a VisualVertex object is about to be removed from the VisualGraph object being laid out.
    
    Specified by:
    
    removeVertex in interface GraphLayoutManager
    
    Parameters:
    
    vVertex - The VisualVertex object to be removed.
  - addEdge
```
public void addEdge(VisualEdge vEdge)
```
    Description copied from interface: GraphLayoutManager
    
    Automatically called when a VisualEdge object has been added to the VisualGraph object being laid out.
    
    Specified by:
    
    addEdge in interface GraphLayoutManager
    
    Parameters:
    
    vEdge - The newly added VisualEdge object.
  - run
```
public void run()
```
    Specified by:
    
    run in interface Runnable

Class ForceDirectedLayout

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ForceDirectedLayout

Method Detail

getSpringLength

getStiffness

getEletricalRepulsion

getIncrement

setSpringLength

setStiffness

setEletricalRepulsion

setIncrement

addFixedVertex

isVertexFixed

removeFixedVertex

isInitialized

paintEdge

routeEdge

layout

drawLayout

addVertex

removeEdge

removeVertex

addEdge

run