Package com.adobe.flex.extras.controls.springgraph
Class public class SpringGraph
Inheritance SpringGraph Inheritance mx.containers.Canvas
Subclasses Roamer

The SpringGraph component displays a set of objects, using a force-directed layout algorithm to position the objects. Behind the objects, the component draws lines connecting items that are linked.

The set of objects, and the links between them, is defined by this component's dataProvider property. For each Item in the dataProvider, there is a corresonding itemRenderer, which is any UIComponent that implements the IDataRenderer interface. You define these via the itemRenderer or viewFactory properties. Each itemRenderer's 'data' property is a reference to its corresponding Item.

SpringGraph does its drawing of lines and items inside the area that you define as the height and width of this component.

You can control what links look like, in 4 ways:
1. do nothing. The edges will draw in a default width and color
2. set 'lineColor'. The edges will draw with that color, in a default width.
3. use Graph.link() to add a data object to any particular link. If that data object contains a field called 'settings', then the value of 'settings' should be an object with fields 'color', 'thickness', and 'alpha'. For example:

var data: Object = {settings: {alpha: 0.5, color: 0, thickness: 2}};
g.link(fromItem, toItem, data);

4. define an EdgeRenderer (see 'edgeRenderer' below)

This component allows the user to click on items and drag them around.

This component was written by Mark Shepherd of Adobe Flex Builder Engineering. The force-directed layout algorithm was translated and adapted to ActionScript 3 from Java code written by Alexander Shapiro of TouchGraph, Inc. (http://www.touchgraph.com).

MXML Syntax expanded Hide MXML Syntax

The <SpringGraph> tag inherits all the tag attributes of its superclass, and adds the following tag attributes:

  <mx:SpringGraph
    Properties
    dataProvider="null"
    itemRenderer="null"
    lineColor="0xcccccc"
    replusionFactor="0.75"
  />

Public Properties
  Property Defined by
    addItemEffect : Effect
An effect that applied to all itemRenderer instances when they are add to the spring graph.
SpringGraph
    autoFit : Boolean
[write-only] Enable/disable the auto-fit feature.
SpringGraph
    dataProvider : Object
Defines the data model for this springgraph.
SpringGraph
    edgeRenderer : IEdgeRenderer
[write-only] Defines an Edge Renderer object that we will use to render edges.
SpringGraph
    itemRenderer : IFactory
[write-only] Defines the UIComponent class for rendering an item.
SpringGraph
    lineColor : int
[write-only] The color we use to draw the lines that represent links between items.
SpringGraph
    motionThreshold : Number
[for experimental use].
SpringGraph
    removeItemEffect : Effect
An effect that is applied to all itemRenderer instances when they are removed from the spring graph.
SpringGraph
    repulsionFactor : Number
How strongly do items push each other away.
SpringGraph
    viewFactory : IViewFactory
[write-only] A factory that can create views for specific Items.
SpringGraph
    xmlNames : Array
[write-only]The XML element and attribute names to use when parsing an XML dataProvider.
SpringGraph
Public Methods
  Method Defined by
   
SpringGraph()
SpringGraph
   
empty():void
Throw away the dataProvider, leaving an empty graph.
SpringGraph
   
refresh():void
Redraw everything.
SpringGraph
Property detail
addItemEffect property
public var addItemEffect:Effect

An effect that applied to all itemRenderer instances when they are add to the spring graph.

autoFit property  
autoFit:Boolean  [write-only]

Enable/disable the auto-fit feature. When enabled, we automatically and continuously adjust the 'repulsionFactor' property, as well as scroll the viewing area of the roamer, so that the graph items are entirely contained within, and nicely spread out over the entire rectangle of this component. When disabled, we obey whatever value you set into the 'repulsionFactor' property, and scrolling must be done manually. When autoFit is enabled, you may still set repulsionFactor and scroll - the component will smoothly continue from wherever you left it.

Implementation
    public function set autoFit(value:Boolean):void
dataProvider property  
dataProvider:Object  [read-write]

Defines the data model for this springgraph. The data is a set of items which can be linked to each other. You can provide the data as XML, or as a Graph object.

To use XML, provide an object of type XML with the following format:

When the dataProvider is set to XML, we automatically create a Graph that repesents the items and links in the XML data. Each itemRenderer's 'data' property is set to the Item object whose 'id' is the id of an XML Node, and whose 'data' property is the XML object representing the Node. You can use the xmlNames property to define the names that you have used in your XML data. The default XML names 'Node', 'Edge', 'fromID', and 'toID'.

The default value is null.

Implementation
    public function get dataProvider():Object
    public function set dataProvider(value:Object):void
edgeRenderer property  
edgeRenderer:IEdgeRenderer  [write-only]

Defines an Edge Renderer object that we will use to render edges. If this is null, we use our built-in edge renderer.

Implementation
    public function set edgeRenderer(value:IEdgeRenderer):void
itemRenderer property  
itemRenderer:IFactory  [write-only]

Defines the UIComponent class for rendering an item. One instance of this class will be created for each item contained in the "dataProvider" property. You should specify an itemRenderer if you want every type of Item to have the same kind of view. If you want different types of Items to have different views, use viewFactory instead.

The default value is null.

Implementation
    public function set itemRenderer(value:IFactory):void
lineColor property  
lineColor:int  [write-only]

The color we use to draw the lines that represent links between items.

The default value is 0xcccccc.

Implementation
    public function set lineColor(value:int):void
motionThreshold property  
public var motionThreshold:Number

[for experimental use]. The layout computations are stopped when the amount of motion falls below this threshold. I don't know what the units are, the range of meaningful values is from 0.001 to 2.0 or so. Low numbers mean that the layout takes longer to settle down, but gives a better result. High numbers means that the layout will stop sooner, but perhaps with not as nice a layout.

removeItemEffect property  
public var removeItemEffect:Effect

An effect that is applied to all itemRenderer instances when they are removed from the spring graph.

repulsionFactor property  
repulsionFactor:Number  [read-write]

How strongly do items push each other away.

The default value is 0.75.

Implementation
    public function get repulsionFactor():Number
    public function set repulsionFactor(value:Number):void
viewFactory property  
viewFactory:IViewFactory  [write-only]

A factory that can create views for specific Items. This is an instance of a class (or component) that implements the IViewFactory interface. You should specify only one of itemRenderer or viewFactory.

Implementation
    public function set viewFactory(value:IViewFactory):void
xmlNames property  
xmlNames:Array  [write-only]

The XML element and attribute names to use when parsing an XML dataProvider. The array must have 4 elements:

Implementation
    public function set xmlNames(value:Array):void

Constructor detail
SpringGraph () constructor
public function SpringGraph()
Method detail
empty () method
public function empty():void

Throw away the dataProvider, leaving an empty graph.

refresh () method  
public function refresh():void

Redraw everything. Call this when you changed something that could affect the size of any of the active itemRenderers. There is no need to call this when the graph data is changed, we update automatically in that case.