spark.filters.GlowFilter - Adobe® Flex® 4 Language Reference (Flex 4)

Package	spark.filters
Class	public class GlowFilter
Inheritance	GlowFilter BaseDimensionFilter BaseFilter EventDispatcher Object
Implements	IBitmapFilter

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The GlowFilter class lets you apply a glow effect to display objects. You have several options for the style of the glow, including inner or outer glow and knockout mode. The glow filter is similar to the drop shadow filter with the distance and angle properties of the drop shadow filter set to 0. You can apply the filter to any display object (that is, objects that inherit from the DisplayObject class), such as MovieClip, SimpleButton, TextField, and Video objects, as well as to BitmapData objects.

The use of filters depends on the object to which you apply the filter:

To apply filters to display objects, use the filters property (inherited from DisplayObject). Setting the filters property of an object does not modify the object, and you can remove the filter by clearing the filters property.
To apply filters to BitmapData objects, use the BitmapData.applyFilter() method. Calling applyFilter() on a BitmapData object takes the source BitmapData object and the filter object and generates a filtered image as a result.

If you apply a filter to a display object, the cacheAsBitmap property of the display object is set to true. If you clear all filters, the original value of cacheAsBitmap is restored.

This filter supports Stage scaling. However, it does not support general scaling, rotation, and skewing. If the object itself is scaled (if scaleX and scaleY are set to a value other than 1.0), the filter is not scaled. It is scaled only when the user zooms in on the Stage.

A filter is not applied if the resulting image exceeds the maximum dimensions. In AIR 1.5 and Flash Player 10, the maximum is 8,191 pixels in width or height, and the total number of pixels cannot exceed 16,777,215 pixels. (So, if an image is 8,191 pixels wide, it can only be 2,048 pixels high.) For example, if you zoom in on a large movie clip with a filter applied, the filter is turned off if the resulting image exceeds the maximum dimensions.

MXML Syntax expanded

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The <s:GlowFilter> tag inherits all of the tag attributes of its superclass and adds the following tag attributes:

  <s:GlowFilter
    Properties
    alpha="1"
    color="0xFF0000"
    inner="false"
  />

View the examples

Public Properties

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	Property		Defined By
		alpha : Number The alpha transparency value for the color.	GlowFilter
		blurX : Number The amount of horizontal blur.	BaseDimensionFilter
		blurY : Number The amount of vertical blur.	BaseDimensionFilter
		color : uint The color of the glow.	GlowFilter
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		inner : Boolean Specifies whether the glow is an inner glow.	GlowFilter
		knockout : Boolean Specifies whether the object has a knockout effect.	BaseDimensionFilter
		prototype : Object [static] A reference to the prototype object of a class or function object.	Object
		quality : int The number of times to apply the filter.	BaseDimensionFilter
		strength : Number The strength of the imprint or spread.	BaseDimensionFilter

Public Methods

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	Method		Defined By
		GlowFilter(color:uint = 0xFF0000, alpha:Number = 1.0, blurX:Number = 4.0, blurY:Number = 4.0, strength:Number = 1, quality:int = 1, inner:Boolean = false, knockout:Boolean = false) Constructor.	GlowFilter
		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
		clone():BitmapFilter Returns a copy of this filter object.	GlowFilter
		dispatchEvent(event:Event):Boolean Dispatches an event into the event flow.	EventDispatcher
		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
		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
		notifyFilterChanged():void	BaseFilter
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		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
		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

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

Public Constants

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	Constant		Defined By
		CHANGE : String = "change" [static]	BaseFilter

Property Detail

alpha

property

alpha:Number

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The alpha transparency value for the color. Valid values are 0 to 1. For example, .25 sets a transparency value of 25%.

The default value is 1.

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

color

property

color:uint

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The color of the glow. Valid values are in the hexadecimal format 0xRRGGBB.

The default value is 0xFF0000.

Implementation
public function get color():uint
public function set color(value:uint):void

inner

property

inner:Boolean

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

Specifies whether the glow is an inner glow. The value true indicates an inner glow. The default is false, meaning an outer glow (a glow around the outer edges of the object).

The default value is false.

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

Constructor Detail

GlowFilter

()

Constructor

public function GlowFilter(color:uint = 0xFF0000, alpha:Number = 1.0, blurX:Number = 4.0, blurY:Number = 4.0, strength:Number = 1, quality:int = 1, inner:Boolean = false, knockout:Boolean = false)

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

Constructor.

Parameters

	`color:uint` (default = `0xFF0000`) — The color of the glow, in the hexadecimal format 0xRRGGBB. The default value is 0xFF0000.

	`alpha:Number` (default = `1.0`) — The alpha transparency value for the color. Valid values are 0 to 1. For example, .25 sets a transparency value of 25%.

	`blurX:Number` (default = `4.0`) — The amount of horizontal blur. Valid values are 0 to 255 (floating point). Values that are a power of 2 (such as 2, 4, 8, 16 and 32) are optimized to render more quickly than other values.

	`blurY:Number` (default = `4.0`) — The amount of vertical blur. Valid values are 0 to 255 (floating point). Values that are a power of 2 (such as 2, 4, 8, 16 and 32) are optimized to render more quickly than other values.

	`strength:Number` (default = `1`) — The strength of the imprint or spread. The higher the value, the more color is imprinted and the stronger the contrast between the glow and the background. Valid values are 0 to 255.

	`quality:int` (default = `1`) — The number of times to apply the filter. Use the BitmapFilterQuality constants: `BitmapFilterQuality.LOW` `BitmapFilterQuality.MEDIUM` `BitmapFilterQuality.HIGH` For more information, see the description of the `quality` property.

	`inner:Boolean` (default = `false`) — Specifies whether the glow is an inner glow. The value `true` specifies an inner glow. The value `false` specifies an outer glow (a glow around the outer edges of the object).

	`knockout:Boolean` (default = `false`) — Specifies whether the object has a knockout effect. The value `true` makes the object's fill transparent and reveals the background color of the document.

clone

()

method

public function clone():BitmapFilter

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

Returns a copy of this filter object.

Returns

BitmapFilter — A new GlowFilter instance with all the properties of the original GlowFilter instance.

Examples ( How to use this example )

GlowFilterExample.mxml

<?xml version="1.0"?>
<!-- filters/examples/GlowFilterExample .mxml -->
<s:Application 
    xmlns:fx="http://ns.adobe.com/mxml/2009" 
    xmlns:mx="library://ns.adobe.com/flex/mx" 
    xmlns:s="library://ns.adobe.com/flex/spark" 
    creationComplete="createFilters()">
    
  <fx:Script><![CDATA[ 
     import spark.filters.*;
     import flash.filters.BitmapFilterQuality;
     import flash.filters.BitmapFilterType;
  
     private var myGlowFilter:GlowFilter;  
     private var color:Number = 0xFF33FF;
  
     public function createFilters():void {        
        myGlowFilter = new GlowFilter(color, .8, 6, 6, .65, BitmapFilterQuality.MEDIUM, 
            false, false);
        b1.filters = [myGlowFilter];
     }
  
  ]]></fx:Script>

    <s:VGroup>
        <!-- This button has a filter applied in ActionScript. -->
        <s:Button id="b1" label="Click me"/>
        
        <!-- This button has a filter applied in MXML. -->
        <s:Button id="b2" label="Click me">
            <s:filters>
                <s:GlowFilter 
                    color="0xFF33FF" 
                    alpha=".8" 
                    blurX="6" 
                    blurY="6" 
                    strength=".65" 
                    quality="{BitmapFilterQuality.MEDIUM}"
                    inner="false" 
                    knockout="false"/>
            </s:filters>
        </s:Button>
        
    </s:VGroup>        
</s:Application>