mx.charts

# LogAxis - AS3 Flex

Package | mx.charts
Class | public class LogAxis
Inheritance | LogAxis NumericAxis AxisBase EventDispatcher Object

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

The LogAxis class maps numeric values logarithmically between a minimum and maximum value along a chart axis. By default, it determines `minimum`, `maximum`, and `interval` values from the charting data to fit all of the chart elements on the screen. You can also explicitly set specific values for these properties. A LogAxis object cannot correctly render negative values, as Log10() of a negative number is `undefined`.

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The `<mx:LogAxis>` tag inherits all the properties of its parent classes and adds the following properties:

      <mx:LogAxis
        Properties
        interval="10"
        maximum="null"
        maximumLabelPrecision="null"
        minimum="null"
      />

View the examples

More examples

Adding axis titles
Disabling axis labels
Customizing axis labels

Learn more

About the axis classes
About the LogAxis subclass

Related API Elements

mx.charts.chartClasses.IAxis

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
|  | constructor : 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
|  | displayName : String The name of the axis. | AxisBase
|  | interval : Number Specifies the multiplier label values along the axis. | LogAxis
|  | labelFunction : Function Called to format axis values for display as labels. | NumericAxis
|  | maximum : Number Specifies the maximum value for an axis label. | LogAxis
|  | maximumLabelPrecision : Number Specifies the maximum number of decimal places for representing fractional values on the labels generated by this axis. | LogAxis
|  | minimum : Number Specifies the minimum value for an axis label. | LogAxis
|  | 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
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| 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
--- | --- | ---
|  | LogAxis() Constructor. | LogAxis
|  | 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
|  | dataChanged():void Triggers events that inform the range object when the chart data has changed. | AxisBase
|  | dispatchEvent(event:Event):Boolean 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
|  | 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
|  | hasEventListener(type:String):Boolean Checks whether the EventDispatcher object has any listeners registered for a specific type of event. | EventDispatcher
|  | hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined. | Object
|  | invertTransform(value:Number):Object Maps a position along the axis back to a numeric data value. | NumericAxis
|  | isPrototypeOf(theClass:Object):Boolean 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
|  | preferDropLabels():Boolean Determines how the axis handles overlapping labels. | NumericAxis
|  | propertyIsEnumerable(name:String):Boolean 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
|  | registerDataTransform(transform:mx.charts.chartClasses:DataTransform, dimensionName:String):void Each DataTransform that makes use of an axis registers itself with that axis. | AxisBase
|  | removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes a listener from the EventDispatcher object. | EventDispatcher
|  | setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations. | Object
|  | toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions. | Object
|  | toString():String 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
|  | unregisterDataTransform(transform:mx.charts.chartClasses:DataTransform):void Each DataTransform that makes use of an axis registers itself with that axis. | AxisBase
|  | update():void Updates the chart. | NumericAxis
|  | valueOf():Object Returns the primitive value of the specified object. | Object
|  | willTrigger(type:String):Boolean Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type. | EventDispatcher

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

Events
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| Event | Summary | Defined By
--- | --- | --- | ---
|  | activate | [broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active. | EventDispatcher
|  | deactivate | [broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive. | EventDispatcher

Property Detail

### interval

property

`interval:Number`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Specifies the multiplier label values along the axis. A value of 10 generates labels at 1, 10, 100, 1000, etc., while a value of 100 generates labels at 1, 100, 10000, etc. Flex calculates the interval if this property is set to `NaN`. Intervals must be even powers of 10, and must be greater than or equal to 10. The LogAxis rounds the interval down to an even power of 10, if necessary.

The default value is `10.`

Implementation
`public function get interval():Number`
`public function set interval(value:Number):void`

### maximum

property

`maximum:Number`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Specifies the maximum value for an axis label. If `NaN`, Flex determines the maximum value from the data in the chart. The maximum value must be an even power of 10. The LogAxis rounds an explicit maximum value up to an even power of 10, if necessary.

The default value is `NaN.`

Implementation
`public function get maximum():Number`
`public function set maximum(value:Number):void`

### maximumLabelPrecision

property

`maximumLabelPrecision:Number`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Specifies the maximum number of decimal places for representing fractional values on the labels generated by this axis. By default, the Axis autogenerates this value from the labels themselves. A value of 0 round to the nearest integer value, while a value of 2 rounds to the nearest 1/100th of a value.

Implementation
`public function get maximumLabelPrecision():Number`
`public function set maximumLabelPrecision(value:Number):void`

### minimum

property

`minimum:Number`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Specifies the minimum value for an axis label. If `NaN`, Flex determines the minimum value from the data in the chart. The minimum value must be an even power of 10. The LogAxis will round an explicit minimum value downward to an even power of 10 if necessary.

The default value is `NaN.`

Implementation
`public function get minimum():Number`
`public function set minimum(value:Number):void`
Constructor Detail

### LogAxis

()
Constructor

`public function LogAxis()`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Constructor.

Examples How to use this example
LogAxisExample.mxml
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    <?xml version="1.0"?>
    <!-- Simple example to demonstrate the LogAxis class. -->
    <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/mx">

        <fx:Script>
            <![CDATA[

            import mx.collections.ArrayCollection;

            [Bindable]
            private var expensesAC:ArrayCollection = new ArrayCollection( [
                { Month: "Jan", Profit: 20000, Expenses: 1500, Amount: 450 },
                { Month: "Feb", Profit: 1000, Expenses: 15000, Amount: 600 },
                { Month: "Mar", Profit: 15000, Expenses: 5000, Amount: 300 },
                { Month: "Apr", Profit: 1800, Expenses: 1200, Amount: 900 },
                { Month: "May", Profit: 2400, Expenses: 575, Amount: 500 } ]);
            ]]>
        </fx:Script>

        <mx:Panel title="LogAxis Example" height="100%" width="100%">

            <mx:LineChart id="linechart" height="100%" width="100%"
                paddingLeft="5" paddingRight="5"
                showDataTips="true" dataProvider="{expensesAC}">

                <mx:horizontalAxis>
                    <mx:CategoryAxis categoryField="Month"/>
                </mx:horizontalAxis>

                <mx:verticalAxis>
                    <mx:LogAxis interval="10"/>
                </mx:verticalAxis>

                <mx:series>
                    <mx:LineSeries yField="Profit" form="curve" displayName="Profit"/>
                    <mx:LineSeries yField="Expenses" form="curve" displayName="Expenses"/>
                    <mx:LineSeries yField="Amount" form="curve" displayName="Amount"/>
                </mx:series>
            </mx:LineChart>

            <mx:Legend dataProvider="{linechart}"/>

        </mx:Panel>
    </s:Application>

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Mon Apr 10 2017, 12:28 PM -07:00