prefuse.action.layout.graph
Class RadialTreeLayout

java.lang.Object
  prefuse.activity.Activity
      prefuse.action.Action
          prefuse.action.GroupAction
              prefuse.action.layout.Layout
                  prefuse.action.layout.graph.TreeLayout
                      prefuse.action.layout.graph.RadialTreeLayout

public class RadialTreeLayout
extends TreeLayout

TreeLayout instance that computes a radial layout, laying out subsequent depth levels of a tree on circles of progressively increasing radius.

The algorithm used is that of Ka-Ping Yee, Danyel Fisher, Rachna Dhamija, and Marti Hearst in their research paper Animated Exploration of Dynamic Graphs with Radial Layout, InfoVis 2001. This algorithm computes a radial layout which factors in possible variation in sizes, and maintains both orientation and ordering constraints to facilitate smooth and understandable transitions between layout configurations.

Author:

jeffrey heer

Nested Class Summary

static class

RadialTreeLayout.Params Wrapper class holding parameters used for each node in this layout.

Field Summary

static int	DEFAULT_RADIUS
protected boolean	m_autoScale
protected int	m_maxDepth
protected java.awt.geom.Point2D	m_origin
protected NodeItem	m_prevRoot
protected double	m_radiusInc
protected boolean	m_setTheta
protected double	m_theta1
protected double	m_theta2
static java.lang.String	PARAMS The data field in which the parameters used by this layout are stored.
static Schema	PARAMS_SCHEMA The schema for the parameters used by this layout.

Fields inherited from class prefuse.action.layout.graph.TreeLayout

m_root

Fields inherited from class prefuse.action.layout.Layout

m_anchor, m_bounds, m_bpts, m_insets, m_margin, m_tmpa, m_tmpb

Fields inherited from class prefuse.action.GroupAction

m_group

Fields inherited from class prefuse.action.Action

m_vis

Fields inherited from class prefuse.activity.Activity

DEFAULT_STEP_TIME, INFINITY

Constructor Summary

RadialTreeLayout(java.lang.String group)
Creates a new RadialTreeLayout.

RadialTreeLayout(java.lang.String group, int radius)
Creates a new RadialTreeLayout using the specified radius increment between levels of the layout.

Method Summary

boolean	getAutoScale() Indicates if the layout automatically scales to fit the layout bounds.
double	getRadiusIncrement() Set the radius increment to use between concentric circles.
protected void	initSchema(TupleSet ts)
protected void	layout(NodeItem n, double r, double theta1, double theta2) Compute the layout.
void	run(double frac) Runs this Action, triggering whatever processing this Action performs.
void	setAngularBounds(double theta, double width) Constrains this layout to the specified angular sector
void	setAutoScale(boolean s) Set whether or not the layout should automatically scale itself to fit the layout bounds.
protected void	setPolarLocation(NodeItem n, NodeItem p, double r, double t) Set the position of the given node, given in polar co-ordinates.
void	setRadiusIncrement(double inc) Set the radius increment to use between concentric circles.
protected void	setScale(java.awt.geom.Rectangle2D bounds)

Methods inherited from class prefuse.action.layout.graph.TreeLayout

getLayoutRoot, setLayoutRoot

Methods inherited from class prefuse.action.layout.Layout

getLayoutAnchor, getLayoutBounds, setLayoutAnchor, setLayoutBounds, setMargin, setX, setY

Methods inherited from class prefuse.action.GroupAction

getGroup, setGroup

Methods inherited from class prefuse.action.Action

getVisualization, run, setVisualization

Methods inherited from class prefuse.activity.Activity

addActivityListener, alwaysRunAfter, cancel, fireActivityCancelled, fireActivityFinished, fireActivityScheduled, fireActivityStarted, fireActivityStepped, getDuration, getNextTime, getPace, getPacingFunction, getStartTime, getStepTime, getStopTime, isEnabled, isRunning, isScheduled, removeActivityListener, run, runAfter, runAt, setDuration, setEnabled, setPacingFunction, setStartTime, setStepTime

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_RADIUS

public static final int DEFAULT_RADIUS

See Also:

Constant Field Values

m_maxDepth

protected int m_maxDepth

m_radiusInc

protected double m_radiusInc

m_theta1

protected double m_theta1

m_theta2

protected double m_theta2

m_setTheta

protected boolean m_setTheta

m_autoScale

protected boolean m_autoScale

m_origin

protected java.awt.geom.Point2D m_origin

m_prevRoot

protected NodeItem m_prevRoot

PARAMS

public static final java.lang.String PARAMS

The data field in which the parameters used by this layout are stored.

See Also:

Constant Field Values

PARAMS_SCHEMA

public static final Schema PARAMS_SCHEMA

The schema for the parameters used by this layout.

Constructor Detail

RadialTreeLayout

public RadialTreeLayout(java.lang.String group)

Creates a new RadialTreeLayout. Automatic scaling of the radius values to fit the layout bounds is enabled by default.

Parameters:

group - the data group to process. This should resolve to either a Graph or Tree instance.

RadialTreeLayout

public RadialTreeLayout(java.lang.String group,
                        int radius)

Creates a new RadialTreeLayout using the specified radius increment between levels of the layout. Automatic scaling of the radius values is disabled by default.

Parameters:

group - the data group to process. This should resolve to either a Graph or Tree instance.

radius - the radius increment to use between subsequent rings in the layout.

Method Detail

getRadiusIncrement

public double getRadiusIncrement()

Set the radius increment to use between concentric circles. Note that this value is used only if auto-scaling is disabled.

Returns:

the radius increment between subsequent rings of the layout when auto-scaling is disabled

setRadiusIncrement

public void setRadiusIncrement(double inc)

Set the radius increment to use between concentric circles. Note that this value is used only if auto-scaling is disabled.

Parameters:

inc - the radius increment between subsequent rings of the layout

See Also:

setAutoScale(boolean)

getAutoScale

public boolean getAutoScale()

Indicates if the layout automatically scales to fit the layout bounds.

Returns:

true if auto-scaling is enabled, false otherwise

setAutoScale

public void setAutoScale(boolean s)

Set whether or not the layout should automatically scale itself to fit the layout bounds.

Parameters:

s - true to automatically scale to fit display, false otherwise

setAngularBounds

public void setAngularBounds(double theta,
                             double width)

Constrains this layout to the specified angular sector

Parameters:

theta - the starting angle, in radians

width - the angular width, in radians

run

public void run(double frac)

Description copied from class: Action

Runs this Action, triggering whatever processing this Action performs. Subclass this method to create custom Actions.

Specified by:

run in class GroupAction

Parameters:

frac - the fraction of this Action's duration that has elapsed.

See Also:

Action.run(double)

setScale

protected void setScale(java.awt.geom.Rectangle2D bounds)

layout

protected void layout(NodeItem n,
                      double r,
                      double theta1,
                      double theta2)

Compute the layout.

Parameters:

n - the root of the current subtree under consideration

r - the radius, current distance from the center

theta1 - the start (in radians) of this subtree's angular region

theta2 - the end (in radians) of this subtree's angular region

setPolarLocation

protected void setPolarLocation(NodeItem n,
                                NodeItem p,
                                double r,
                                double t)

Set the position of the given node, given in polar co-ordinates.

Parameters:

n - the NodeItem to set the position

p - the referrer parent NodeItem

r - the radius

t - the angle theta

initSchema

protected void initSchema(TupleSet ts)