flare.vis.operator.label.Labeler

Package	flare.vis.operator.label
Class	public class Labeler
Inheritance	Labeler Operator
Subclasses	RadialLabeler, StackedAreaLabeler

Labeler that adds labels for items in a visualization. By default, this operator adds labels that are centered on each data sprite; this can be changed by configuring the offset and anchor settings.

Labelers support two different approaches for adding labels: CHILD mode (the default) and LAYER mode.

In CHILD mode, labels are added as children of DataSprite instances and so become part of the data sprite itself. In this mode, labels will automatically change position as data sprites are re-positioned.
In LAYER mode, labels are instead added to a separate layer of the visualization above the Visualization.marks layer that contains the data sprites. A new layer will be created as needed and can be accessed through the Visualization.labels property. This mode is particularly useful for ensuring that no labels can be occluded by data marks. In LAYER mode, labels will not automatically move along with the labeled DataSprite instances if they are re-positioned. Instead, the labeler must be re-run to keep the layout current.

To access created labels after a Labeler has been run, use the props.label property of a DataSprite. To have labels stored under a different property name, set the access property of this class to the desired name.

	Property	Defined by
		access : String The name of the property in which to store created labels.	Labeler
		cacheText : Boolean Boolean function indicating whether label text values should be cached or not.	Labeler
		enabled : Boolean Indicates if the operator is enabled or disabled.	Operator
		filter : Function Boolean function indicating which items to process.	Labeler
		group : String The name of the data group to label.	Labeler
		horizontalAnchor : int = 1 The horizontal alignment for labels.	Labeler
		labelPolicy : String [read-only] The policy for how labels should be applied.	Labeler
		labels : Sprite [read-only] A sprite containing the labels, if a layer policy is used.	Labeler
		parameters : Object Sets parameter values for this operator.	Operator
		source : String The source property that provides the label text.	Labeler
		textFormat : TextFormat The text format to apply to labels.	Labeler
		textFunction : Function = null Optional function for determining label text.	Labeler
		textMode : int = 2 The text mode to use for the TextSprite labels.	Labeler
		verticalAnchor : int = 1 The vertical alignment for labels.	Labeler
		visualization : Visualization The visualization processed by this operator.	Operator
		xOffset : Number = 0 The default `x` value for labels.	Labeler
		yOffset : Number = 0 The default `y` value for labels.	Labeler

	Method	Defined by
		Labeler(source:* = null, group:String, format:TextFormat = null, filter:String = null, policy:*) Creates a new Labeler.	Labeler
		applyParameters(op:IOperator, params:Object):void [static] Static method that applies parameter settings to an operator.	Operator
		operate(t:Transitioner = null):void Performs an operation over the contents of a visualization.	Labeler
		setup():void Setup method invoked whenever this operator's visualization property is set.	Labeler

	Method	Defined by
		getLabel(d:DataSprite, create:Boolean = false, visible:Boolean = true):TextSprite Retrives and optionally creates a label TextSprite for the given data sprite.	Labeler
		getLabelText(d:DataSprite):String Computes the label text for a given sprite.	Labeler
		process(d:DataSprite):void Performs label creation and layout for the given data sprite.	Labeler

	Constant	Defined by
		CHILD : String = "child" [static] Constant indicating that labels be added as children.	Labeler
		LAYER : String = "layer" [static] Constant indicating that labels be placed in their own layer.	Labeler

Property detail

access

property

access:String [read-write]

The name of the property in which to store created labels. The default is "props.label".

Implementation
public function get access():String
public function set access(value:String):void

cacheText

property

cacheText:Boolean [read-write]

Boolean function indicating whether label text values should be cached or not. If set to true then the label text is calculated only the first time it's needed and re-used from them on. If set to false then the label is recalculated at each update.

Implementation
public function get cacheText():Boolean
public function set cacheText(value:Boolean):void

filter

property

filter:Function [read-write]

Boolean function indicating which items to process. Only items for which this function return true will be considered by the labeler. If the function is null, all items will be considered.

Implementation
public function get filter():Function
public function set filter(value:Function):void

See also

flare.display.TextSprite

labelPolicy

property

labelPolicy:String [read-only]

The policy for how labels should be applied. One of LAYER (for adding a separate label layer) or CHILD (for adding labels as children of data objects).

Implementation
public function get labelPolicy():String

labels

property

labels:Sprite [read-only]

A sprite containing the labels, if a layer policy is used.

Implementation
public function get labels():Sprite

source

property

source:String [read-write]

The source property that provides the label text. This property will be ignored if the textFunction property is non-null.

Implementation


    public function get source():String


    public function set source(value:String):void





textFormat property  



public var textFormat:TextFormat The text format to apply to labels. 



textFunction property  



public var textFunction:Function = null Optional function for determining label text. 



textMode property  



public var textMode:int = 2 The text mode to use for the TextSprite labels.
    

See also


flare.display.TextSprite





verticalAnchor property  



public var verticalAnchor:int = 1 The vertical alignment for labels.
    

See also


flare.display.TextSprite





xOffset property  



public var xOffset:Number = 0 The default x value for labels. 



yOffset property  



public var yOffset:Number = 0 The default y value for labels. 

Constructor detail



Labeler () constructor



public function Labeler(source:* = null, group:String, format:TextFormat = null, filter:String = null, policy:*)
   Creates a new Labeler. 
   
Parameters


source:* (default = null) — the property from which to retrieve the label text.
    If this value is a string or property instance, the label text will
    be pulled directly from the named property. If this value is a
    Function or Expression instance, the value will be used to set the
    textFunction property and the label text will be
    determined by evaluating that function.
   


 


group:String — the data group to process
   


 


format:TextFormat (default = null) — optional text formatting information for labels
   


 


filter:String (default = null) — a Boolean-valued filter function determining which
    items will be given labels
   


 


policy:* — the label creation policy. One of LAYER (for adding a
    separate label layer) or CHILD (for adding labels as children of
    data objects)
   




Method detail



getLabel () method



protected function getLabel(d:DataSprite, create:Boolean = false, visible:Boolean = true):TextSprite
   Retrives and optionally creates a label TextSprite for the given
    data sprite. 
   
Parameters


d:DataSprite — the data sprite to process
   


 


create:Boolean (default = false) — if true, a new label will be created as needed
   


 


visible:Boolean (default = true) — indicates if new labels should be visible by default
   



Returns


TextSprite — 
                        the label
   
                        
                     






getLabelText () method  



protected function getLabelText(d:DataSprite):String
   Computes the label text for a given sprite.
   
Parameters


d:DataSprite — the data sprite for which to produce label text
   



Returns


String — the label text
   






operate () method  



public override function operate(t:Transitioner = null):void 
   Performs an operation over the contents of a visualization.
   
Parameters


t:Transitioner (default = null) — a Transitioner instance for collecting value updates.
   






process () method  



protected function process(d:DataSprite):void
   Performs label creation and layout for the given data sprite.
   Subclasses should override this method to perform custom labeling. 
   
Parameters


d:DataSprite — the data sprite to process
   






setup () method  



public override function setup():void 
   Setup method invoked whenever this operator's visualization
   property is set.
   

Constant detail



CHILD constant



public static const CHILD:String = "child" Constant indicating that labels be added as children. 



LAYER constant  



public static const LAYER:String = "layer" Constant indicating that labels be placed in their own layer. 








© 2007-2008 Regents of the University of California. Created Sat Jan 24 2009 11:25 AM.

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Class Labeler	Properties \| Methods \| Constants

	`source:*` (default = `null`) — the property from which to retrieve the label text. If this value is a string or property instance, the label text will be pulled directly from the named property. If this value is a Function or Expression instance, the value will be used to set the `textFunction property and the label text will be determined by evaluating that function.`

	`group:String` — the data group to process

	`format:TextFormat` (default = `null`) — optional text formatting information for labels

	`filter:String` (default = `null`) — a Boolean-valued filter function determining which items will be given labels

	`policy:*` — the label creation policy. One of LAYER (for adding a separate label layer) or CHILD (for adding labels as children of data objects)

	`d:DataSprite` — the data sprite to process

	`create:Boolean` (default = `false`) — if true, a new label will be created as needed

	`visible:Boolean` (default = `true`) — indicates if new labels should be visible by default