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NumericAxis

Package | mx.charts.chartClasses
Class | public class NumericAxis
Inheritance | NumericAxis AxisBase flash.events.EventDispatcher
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

mx.charts.DateTimeAxis
mx.charts.LinearAxis
mx.charts.LogAxis

Public Properties
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| Property | Defined 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
|  | chartDataProvider : 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
|  | direction : String Determines the direction in which the axis is rendered. | NumericAxis
|  | displayName : 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
|  | title : String The text for the title displayed along the axis. | AxisBase
|  | unitSize : Number [read-only] The size of one unit of data as represented by this axis. | AxisBase

Protected Properties

| Property | Defined 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
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| Method | Defined By
--- | --- | ---
|  | NumericAxis() Constructor. | NumericAxis
|  | dataChanged():void Triggers events that inform the range object when the chart data has changed. | AxisBase
|  | 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
|  | formatForScreen(value:Object):String Formats values for display in DataTips. | NumericAxis
|  | getLabelEstimate():AxisLabelSet Determines the range to estimate what the axis labels should be. | NumericAxis
|  | getLabels(minimumAxisLength:Number):AxisLabelSet Gets the labels text that is rendered. | NumericAxis
|  | invertTransform(value:Number):Object Maps a position along the axis back to a numeric data value. | NumericAxis
|  | 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
|  | preferDropLabels():Boolean Determines how the axis handles overlapping labels. | NumericAxis
|  | 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
|  | registerDataTransform(transform:DataTransform, dimensionName:String):void Each DataTransform that makes use of an axis registers itself with that axis. | AxisBase
|  | transformCache(cache:Array, field:String, convertedField:String):void Maps a set of values from data space to screen space. | NumericAxis
|  | unregisterDataTransform(transform:DataTransform):void Each DataTransform that makes use of an axis registers itself with that axis. | AxisBase
|  | update():void Updates the chart. | NumericAxis

Protected Methods
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| Method | Defined By
--- | --- | ---
|  | adjustMinMax(minValue:Number, maxValue:Number):void Adjusts the generated or assigned range of the axis's labels. | NumericAxis
|  | buildLabelCache():Boolean Populates the labelCache property with labels representing the current values of the axis. | NumericAxis
|  | buildMinorTickCache():Array Builds an Array of positions for the minor tick marks Array that is generated by this axis. | NumericAxis
|  | describeData(requiredFields:uint):Array Called by the governing DataTransform to obtain a description of the data represented by this IChartElement. | AxisBase
|  | guardMinMax(min:Number, max:Number):Array Protects the range against invalid values for this axis type. | NumericAxis
|  | invalidateCache():void Invalidates the cached labels and tick marks that represent this axis's values. | NumericAxis

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

| `Boolean` — `true` 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.

Wed Nov 15 2017, 09:50 AM +01:00