Adobe® Flex® 4 Language Reference
Hide Packages and Classes List |  Packages  |  Classes  |  Index  |  Appendixes
mx.charts.chartClasses 
NumericAxis 
Packagemx.charts.chartClasses
Classpublic class NumericAxis
InheritanceNumericAxis Inheritance AxisBase Inheritance EventDispatcher Inheritance Object
Implements IAxis
Subclasses DateTimeAxis, LinearAxis, LogAxis

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The NumericAxis class acts as a common base class for axis types representing a continuous range of values between a defined minimum and maximum. The built-in LinearAxis, LogAxis, and DateTimeAxis classes all extend this base class.

See also



Public Properties
 PropertyDefined By
  autoAdjust : Boolean
Specifies whether Flex rounds values.
NumericAxis
  baseAtZero : Boolean
Specifies whether Flex tries to keep the minimum and maximum values rooted at zero.
NumericAxis
  baseline : Number
[read-only] The computed minimum value for the axis as long as this value is greater than 0.
NumericAxis
 InheritedchartDataProvider : Object
[write-only] The data provider assigned to the enclosing chart.
AxisBase
  computedMaximum : Number
The computed maximum value represented by this axis.
NumericAxis
  computedMinimum : Number
The computed minimum value represented by this axis.
NumericAxis
 Inheritedconstructor : Object
A reference to the class object or constructor function for a given object instance.
Object
  direction : String
Determines the direction in which the axis is rendered.
NumericAxis
 InheriteddisplayName : String
The name of the axis.
AxisBase
  labelFunction : Function
Called to format axis values for display as labels.
NumericAxis
  minorTicks : Array
[read-only] An Array of minor tick marks generated to represent this axis.
NumericAxis
  padding : Number
Specifies padding that Flex adds to the calculated minimum and maximum values for the axis when rendering the values on the screen.
NumericAxis
  parseFunction : Function
Specify a parseFunction to customize how the values rendered by your chart are converted into numeric values.
NumericAxis
 Inheritedprototype : Object
[static] A reference to the prototype object of a class or function object.
Object
 Inheritedtitle : String
The text for the title displayed along the axis.
AxisBase
 InheritedunitSize : Number
[read-only] The size of one unit of data as represented by this axis.
AxisBase
Protected Properties
 PropertyDefined By
  assignedMaximum : Number
The explicitly assigned maximum value.
NumericAxis
  assignedMinimum : Number
The explicitly assigned minimum value.
NumericAxis
  computedInterval : Number
The computed interval represented by this axis.
NumericAxis
  dataDescriptions : Array
[read-only] An Array of DataDescription structures describing the data being represented by the chart.
NumericAxis
  labelCache : Array
The most recent set of AxisLabel objects generated to represent this axis.
NumericAxis
  labelMaximum : Number
The maximum value where a label should be placed.
NumericAxis
  labelMinimum : Number
The minimum value where a label should be placed.
NumericAxis
  minorTickCache : Array
The most recent set of minor tick marks generated to represent this axis.
NumericAxis
  requiredDescribedFields : uint
[read-only] The fields of the DescribeData structure that this axis is interested in.
NumericAxis
  ticks : Array
[read-only] An Array of tick marks for this axis.
NumericAxis
Public Methods
 MethodDefined By
  
Constructor.
NumericAxis
 Inherited
addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void
Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event.
EventDispatcher
 Inherited
Triggers events that inform the range object when the chart data has changed.
AxisBase
 Inherited
Dispatches an event into the event flow.
EventDispatcher
  
filterCache(cache:Array, field:String, filteredField:String):void
Filters a set of values of arbitrary type to a set of numbers that can be mapped.
NumericAxis
  
Formats values for display in DataTips.
NumericAxis
  
Determines the range to estimate what the axis labels should be.
NumericAxis
  
getLabels(minimumAxisLength:Number):AxisLabelSet
Gets the labels text that is rendered.
NumericAxis
 Inherited
Checks whether the EventDispatcher object has any listeners registered for a specific type of event.
EventDispatcher
 Inherited
Indicates whether an object has a specified property defined.
Object
  
Maps a position along the axis back to a numeric data value.
NumericAxis
 Inherited
Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.
Object
  
mapCache(cache:Array, field:String, convertedField:String, indexValues:Boolean = false):void
Converts a set of values of arbitrary type to a set of numbers that can be transformed into screen coordinates.
NumericAxis
  
Determines how the axis handles overlapping labels.
NumericAxis
 Inherited
Indicates whether the specified property exists and is enumerable.
Object
  
reduceLabels(intervalStart:AxisLabel, intervalEnd:AxisLabel):AxisLabelSet
Invoked when an AxisRenderer is unable to cleanly render the labels without overlap, and would like the Axis object to reduce the set of labels.
NumericAxis
 Inherited
Each DataTransform that makes use of an axis registers itself with that axis.
AxisBase
 Inherited
removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void
Removes a listener from the EventDispatcher object.
EventDispatcher
 Inherited
Sets the availability of a dynamic property for loop operations.
Object
 Inherited
Returns the string representation of this object, formatted according to locale-specific conventions.
Object
 Inherited
Returns the string representation of the specified object.
Object
  
transformCache(cache:Array, field:String, convertedField:String):void
Maps a set of values from data space to screen space.
NumericAxis
 Inherited
Each DataTransform that makes use of an axis registers itself with that axis.
AxisBase
  
Updates the chart.
NumericAxis
 Inherited
Returns the primitive value of the specified object.
Object
 Inherited
Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.
EventDispatcher
Protected Methods
 MethodDefined By
  
adjustMinMax(minValue:Number, maxValue:Number):void
Adjusts the generated or assigned range of the axis's labels.
NumericAxis
  
Populates the labelCache property with labels representing the current values of the axis.
NumericAxis
  
Builds an Array of positions for the minor tick marks Array that is generated by this axis.
NumericAxis
 Inherited
describeData(requiredFields:uint):Array
Called by the governing DataTransform to obtain a description of the data represented by this IChartElement.
AxisBase
  
Protects the range against invalid values for this axis type.
NumericAxis
  
Invalidates the cached labels and tick marks that represent this axis's values.
NumericAxis
Events
 Event Summary Defined By
 Inherited[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active.EventDispatcher
 Inherited[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive.EventDispatcher
Property Detail

assignedMaximum

property
protected var assignedMaximum:Number

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The explicitly assigned maximum value. If no value has been assigned, this will be NaN. Typically, calculations should be performed with the computedMaximum field.

assignedMinimum

property 
protected var assignedMinimum:Number

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The explicitly assigned minimum value. If no value has been assigned, this will be NaN. Typically calculations should be performed with the computedMinimum field.

autoAdjust

property 
autoAdjust:Boolean

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Specifies whether Flex rounds values. If false, Flex does not round the values set by the minimum and maximum properties, or modify the default minimum and maximum values.

The default value is true.



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

baseAtZero

property 
baseAtZero:Boolean

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Specifies whether Flex tries to keep the minimum and maximum values rooted at zero. If all axis values are positive, the minimum axis value is zero. If all axis values are negative, the maximum axis value is zero.

The default value is true.



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

baseline

property 
baseline:Number  [read-only]

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The computed minimum value for the axis as long as this value is greater than 0. If the maximum value is less than or equal to 0, then the baseline property is the computed maximum. If neither value is greater than 0, then the baseline property is 0.



Implementation
    public function get baseline():Number

computedInterval

property 
protected var computedInterval:Number

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The computed interval represented by this axis. The computedInterval is used by the AxisRenderer and Gridlines classes to determine where to render tick marks and grid lines. The NumericAxis base class watches this field for changes to determine if the chart needs to be re-rendered. Derived classes are responsible for computing the value of this field.

computedMaximum

property 
public var computedMaximum:Number

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The computed maximum value represented by this axis. If the user has explicitly assigned a maximum value, the computedMaximum and assignedMaximum properties are usually the same. Otherwise, the computedMaximum is generated from the values represented in the chart.

computedMinimum

property 
public var computedMinimum:Number

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The computed minimum value represented by this axis. If the user has explicitly assigned a minimum value, the computedMinimum and assignedMinimum properties are usually be the same. Otherwise, the computedMinimum is generated from the values represented in the chart.

dataDescriptions

property 
dataDescriptions:Array  [read-only]

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

An Array of DataDescription structures describing the data being represented by the chart. An axis can use this property to generate values for properties, such as its range.



Implementation
    protected function get dataDescriptions():Array

direction

property 
direction:String

Language Version: ActionScript 3.0
Product Version: Flex 4
Runtime Versions: Flash Player 9, AIR 1.1

Determines the direction in which the axis is rendered. Possible values are normal, and inverted. All derived classes should take care of the way min and max are set depending on direction. All series should take care of the way it is rendered depending on the direction of its underlying axis.

The default value is "normal".



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

labelCache

property 
protected var labelCache:Array

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The most recent set of AxisLabel objects generated to represent this axis. This property is null if the axis has been modified and requires new labels. To guarantee that the value of the labelCache property is correct, call the buildLabelCache() method before accessing the labelCache property.

labelFunction

property 
labelFunction:Function

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Called to format axis values for display as labels. A labelFunction has the following signature:

      function function_name(labelValue:Object, previousValue:Object, axis:IAxis):String { ... }
      

If you know the types of the data your function will be formatting, you can specify an explicit type for the labelValue and previousValue parameters.



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

labelMaximum

property 
protected var labelMaximum:Number

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The maximum value where a label should be placed. After computing an adjusted minimum value, many axis types expand the range of the axis further to make room for additional rendering artifacts in the chart, such as labels and borders. This value represents the maximum value in the chart before it is adjusted for these artifacts. Typically axes generate labels to make sure this value is labeled, rather than the adjusted maximum of the axis.

labelMinimum

property 
protected var labelMinimum:Number

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The minimum value where a label should be placed. After computing an adjusted minimum value, many axis types expand the range of the axis further to make room for additional rendering artifacts in the chart, such as labels and borders. This value represents the minimum value in the chart before it is adjusted for these artifacts. Typically axes will generate labels to make sure this value is labeled, rather than the adjusted minimum of the axis.

minorTickCache

property 
protected var minorTickCache:Array

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The most recent set of minor tick marks generated to represent this axis. This property may be null if the axis has been modified and requires new labels and tick marks. Use the public accessor minorTicks to build the minor tick marks on demand.

minorTicks

property 
minorTicks:Array  [read-only]

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

An Array of minor tick marks generated to represent this axis.



Implementation
    public function get minorTicks():Array

padding

property 
padding:Number

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Specifies padding that Flex adds to the calculated minimum and maximum values for the axis when rendering the values on the screen.



Implementation
    public function get padding():Number
    public function set padding(value:Number):void

parseFunction

property 
parseFunction:Function

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Specify a parseFunction to customize how the values rendered by your chart are converted into numeric values. A custom parseFunction is passed a data value and should return a corresponding number representing the same value. By default, this axis uses the ECMA function parseFloat().



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

requiredDescribedFields

property 
requiredDescribedFields:uint  [read-only]

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The fields of the DescribeData structure that this axis is interested in.



Implementation
    protected function get requiredDescribedFields():uint

ticks

property 
ticks:Array  [read-only]

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

An Array of tick marks for this axis.



Implementation
    protected function get ticks():Array
Constructor Detail

NumericAxis

()Constructor
public function NumericAxis()

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Constructor.

Method Detail

adjustMinMax

()method
protected function adjustMinMax(minValue:Number, maxValue:Number):void

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Adjusts the generated or assigned range of the axis's labels. This method is called during the update cycle of the axis. Subclasses can override this method to do special processing on the values. By default, no adjustments are made to the range.

Parameters

minValue:Number — The computed minimum value.
 
maxValue:Number — The computed maximum value.

buildLabelCache

()method 
protected function buildLabelCache():Boolean

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Populates the labelCache property with labels representing the current values of the axis. Subclasses must implement this function. This function is called many times, so you should check to see if the labelCache property is null before performing any calculations.

Returns
Boolean — true if the labels were regenerated.

buildMinorTickCache

()method 
protected function buildMinorTickCache():Array

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Builds an Array of positions for the minor tick marks Array that is generated by this axis. Subclasses must implement this function. This function is called automatically by the NumericAxis. You should access the minorTicks property instead of calling this function directly.

Returns
Array — An Array of positions from 0 to 1 that represent points between the axis minimum and maximum values where minor tick marks are rendered.

filterCache

()method 
public function filterCache(cache:Array, field:String, filteredField:String):void

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Filters a set of values of arbitrary type to a set of numbers that can be mapped.

Parameters

cache:Array — An Array of objects where converted values are read from and stored.
 
field:String — The field of the objects in the cache Array containing the pre-filtered values.
 
filteredField:String — The field of the objects in the cache Array where filtered values should be stored.

formatForScreen

()method 
public function formatForScreen(value:Object):String

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Formats values for display in DataTips. Returns a user-readable string.

Parameters

value:Object — The value to convert to a String.

Returns
String — The text of the DataTip.

getLabelEstimate

()method 
public function getLabelEstimate():AxisLabelSet

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Determines the range to estimate what the axis labels should be. The axis almost immediately calls the getLabels() method to get the real values. The axis uses the estimated values to adjust chart margins, so any difference between the estimated labels and actual labels (returned from the getLabels() method) results in scaling the labels to fit.

An axis need only return the minimum and maximum labels when returning an estimate. If the label set is fairly static, without depending on the size of the axis being rendered on screen, an axis can return the entire label set from this function, and mark the estimate as accurate.

Returns
AxisLabelSet — An Array of AxisLabel objects.

getLabels

()method 
public function getLabels(minimumAxisLength:Number):AxisLabelSet

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Gets the labels text that is rendered. When Flex calls this method, the axis has already determined the minimum length of the label.

Parameters

minimumAxisLength:Number — The minimum length of the axis, in pixels. The axis can be longer than this value, but not shorter.

Returns
AxisLabelSet — An array of AxisLabel objects.

guardMinMax

()method 
protected function guardMinMax(min:Number, max:Number):Array

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Protects the range against invalid values for this axis type. This function is called during the update cycle of the axis to guarantee that invalid ranges are not generated. Subclasses can override this class and define logic that is appropriate to their axis type.

Parameters

min:Number — The computed minimum value.
 
max:Number — The computed maximum value.

Returns
Array — null if no adjustment is necessary, or an Array containing the adjusted values of the form [min,max].

invalidateCache

()method 
protected function invalidateCache():void

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Invalidates the cached labels and tick marks that represent this axis's values. Derived classes should call this function whenever values used in the calculation of labels and tick marks change.

invertTransform

()method 
public function invertTransform(value:Number):Object

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Maps a position along the axis back to a numeric data value.

Parameters

value:Number — The bound of the axis. This parameter should be between 0 and 1, with 0 representing the minimum bound of the axis, and 1 the maximum.

Returns
Object — An object containing the transformed value.

mapCache

()method 
public function mapCache(cache:Array, field:String, convertedField:String, indexValues:Boolean = false):void

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Converts a set of values of arbitrary type to a set of numbers that can be transformed into screen coordinates.

Parameters

cache:Array — An Array of objects where converted values are read from and stored.
 
field:String — The field of the objects in the cache Array containing the pre-converted values.
 
convertedField:String — The field of the objects in the cache Array where converted values should be stored.
 
indexValues:Boolean (default = false) — This parameter is true if the values being mapped are index values, and false if they are natural data values.

preferDropLabels

()method 
public function preferDropLabels():Boolean

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Determines how the axis handles overlapping labels. Typically, numeric ranges return true, while discrete value-based ranges do not. You can can override this property by setting it directly on the axis.

Returns
Booleantrue if labels can be dropped without loss of data; otherwise, false.

reduceLabels

()method 
public function reduceLabels(intervalStart:AxisLabel, intervalEnd:AxisLabel):AxisLabelSet

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Invoked when an AxisRenderer is unable to cleanly render the labels without overlap, and would like the Axis object to reduce the set of labels. The method is passed the two labels that are overlapping.

Parameters

intervalStart:AxisLabel — The start of the interval where labels overlap.
 
intervalEnd:AxisLabel — The end of the interval where labels overlap.

Returns
AxisLabelSet — A new label set that resolves the overlap by reducing the number of labels.

transformCache

()method 
public function transformCache(cache:Array, field:String, convertedField:String):void

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Maps a set of values from data space to screen space.

Parameters

cache:Array — An Array of objects where mapped values are read from and stored.
 
field:String — The field of the objects in the cache Array containing the pre-mapped values.
 
convertedField:String — The field of the objects in the cache Array where mapped values should be stored.

update

()method 
public function update():void

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Updates the chart. This can be called multiple times per frame.