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

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

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The ConvolutionFilter class applies a matrix convolution filter effect. A convolution combines pixels in the input image with neighboring pixels to produce an image. A wide variety of image effects can be achieved through convolutions, including blurring, edge detection, sharpening, embossing, and beveling. 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.

To create a convolution filter, use the syntax new ConvolutionFilter(). The use of filters depends on the object to which you apply the filter:

To apply filters to movie clips, text fields, buttons, and video, 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 value of the cacheAsBitmap property of the object is set to true. If you clear all filters, the original value of cacheAsBitmap is restored.

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 maximum dimensions.

MXML Syntax expanded

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

 <s:ConvolutionFilter 
   Properties
   alpha="1"
   clamp="true"
   color="0xFF0000"
   divisor="1.0"
   matrix="[]"
   matrixX="0"
   matrixY="0"
   preserveAlpha="true"
 />

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Public Properties

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	Property		Defined By
		alpha : Number The alpha transparency value for the color.	ConvolutionFilter
		bias : Number The amount of bias to add to the result of the matrix transformation.	ConvolutionFilter
		clamp : Boolean Indicates whether the image should be clamped.	ConvolutionFilter
		color : uint The color of the glow.	ConvolutionFilter
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		divisor : Number The divisor used during matrix transformation.	ConvolutionFilter
		matrix : Array The amount of horizontal blur.	ConvolutionFilter
		matrixX : Number The x dimension of the matrix (the number of rows in the matrix).	ConvolutionFilter
		matrixY : Number The y dimension of the matrix (the number of columns in the matrix).	ConvolutionFilter
		preserveAlpha : Boolean Indicates if the alpha channel is preserved without the filter effect or if the convolution filter is applied to the alpha channel as well as the color channels.	ConvolutionFilter
		prototype : Object [static] A reference to the prototype object of a class or function object.	Object

Public Methods

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	Method		Defined By
		ConvolutionFilter(matrixX:Number = 0, matrixY:Number = 0, matrix:Array = null, divisor:Number = 1.0, bias:Number = 0.0, preserveAlpha:Boolean = true, clamp:Boolean = true, color:uint = 0, alpha:Number = 0.0) Constructor.	ConvolutionFilter
		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.	ConvolutionFilter
		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

bias

property

bias:Number

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The amount of bias to add to the result of the matrix transformation. The bias increases the color value of each channel, so that dark colors appear brighter.

The default value is 0.

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

clamp

property

clamp:Boolean

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

Indicates whether the image should be clamped. For pixels off the source image, a value of true indicates that the input image is extended along each of its borders as necessary by duplicating the color values at each respective edge of the input image. A value of false indicates that another color should be used, as specified in the color and alpha properties.

The default value is true.

Implementation
public function get clamp():Boolean
public function set clamp(value:Boolean):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

divisor

property

divisor:Number

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The divisor used during matrix transformation. The default value is 1. A divisor that is the sum of all the matrix values smooths out the overall color intensity of the result. A value of 0 is ignored and the default is used instead.

The default value is 1.0.

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

matrix

property

matrix:Array

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The amount of horizontal blur. Valid values are 0 to 255. A blur of 1 or less means that the original image is copied as is. The default value is 4. Values that are a power of 2 (such as 2, 4, 8, 16, and 32) are optimized to render more quickly than other values.

The default value is [].

Implementation
public function get matrix():Array
public function set matrix(value:Array):void

matrixX

property

matrixX:Number

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The x dimension of the matrix (the number of rows in the matrix).

The default value is 0.

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

matrixY

property

matrixY:Number

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The y dimension of the matrix (the number of columns in the matrix).

The default value is 0.

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

preserveAlpha

property

preserveAlpha:Boolean

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

Indicates if the alpha channel is preserved without the filter effect or if the convolution filter is applied to the alpha channel as well as the color channels. A value of false indicates that the convolution applies to all channels, including the alpha channel. A value of true indicates that the convolution applies only to the color channels.

The default value is true.

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

Constructor Detail

ConvolutionFilter

()

Constructor

public function ConvolutionFilter(matrixX:Number = 0, matrixY:Number = 0, matrix:Array = null, divisor:Number = 1.0, bias:Number = 0.0, preserveAlpha:Boolean = true, clamp:Boolean = true, color:uint = 0, alpha:Number = 0.0)

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

Constructor.

Parameters

	`matrixX:Number` (default = `0`) — The x dimension of the matrix (the number of columns in the matrix). The default value is 0.

	`matrixY:Number` (default = `0`) — The y dimension of the matrix (the number of rows in the matrix). The default value is 0.

	`matrix:Array` (default = `null`) — The array of values used for matrix transformation. The number of items in the array must equal `matrixX * matrixY`.

	`divisor:Number` (default = `1.0`) — The divisor used during matrix transformation. The default value is 1. A divisor that is the sum of all the matrix values evens out the overall color intensity of the result. A value of 0 is ignored and the default is used instead.

	`bias:Number` (default = `0.0`) — The bias to add to the result of the matrix transformation. The default value is 0.

	`preserveAlpha:Boolean` (default = `true`) — A value of `false` indicates that the alpha value is not preserved and that the convolution applies to all channels, including the alpha channel. A value of `true` indicates that the convolution applies only to the color channels. The default value is `true`.

	`clamp:Boolean` (default = `true`) — For pixels that are off the source image, a value of `true` indicates that the input image is extended along each of its borders as necessary by duplicating the color values at the given edge of the input image. A value of `false` indicates that another color should be used, as specified in the `color` and `alpha` properties. The default is `true`.

	`color:uint` (default = `0`) — The hexadecimal color to substitute for pixels that are off the source image.

	`alpha:Number` (default = `0.0`) — The alpha of the substitute color.

Method Detail

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 — BitmapFilter A new ConvolutionFilter instance with all the same properties as the original ConvolutionMatrixFilter instance.

Examples How to use this example

ConvolutionFilterExample.mxml

<?xml version="1.0"?>
<!-- filters/examples/ConvolutionGlowFilterExample .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 myOutlineConvolutionFilter:ConvolutionFilter;  
     private var mySharpnessConvolutionFilter:ConvolutionFilter;  
     private var myBrightnessConvolutionFilter:ConvolutionFilter;  

     private var outlineMatrix:Array = [    -30, 30, 0,
                                                          -30, 30, 0,
                                                          -30, 30, 0 ];

     private var sharpnessMatrix:Array = [0, -1, 0,
                                                          -1, 20, -1,
                                                          0, -1, 0];

     private var brightnessMatrix:Array = [2, 2, 2,
                                                          2, 0, 2, 
                                                          2, 2, 2];
             
     public function createFilters():void {        
        myOutlineConvolutionFilter = new ConvolutionFilter(3, 3, outlineMatrix, 9, 0, true, true, 0x00CC99, 0);
        mySharpnessConvolutionFilter = new ConvolutionFilter(3, 3, sharpnessMatrix, 9, 0, true, true, 0x00CC99, 0);
        myBrightnessConvolutionFilter = new ConvolutionFilter(3, 3, brightnessMatrix, 3, 0, true, true, 0x00CC99, 0);

        outlineImage.filters = [myOutlineConvolutionFilter];
        sharpnessImage.filters = [mySharpnessConvolutionFilter];
        brightnessImage.filters = [myBrightnessConvolutionFilter];
     }
  
  ]]></fx:Script>

    <s:VGroup>
        <s:VGroup>
            <s:Label text="Original Image"/>
            <mx:Image id="originalImage" source="@Embed(source='assets/Nokia_6630.png')"/>
        </s:VGroup>        

        <s:VGroup>
            <s:Label text="Outline Matrix Image"/>
            <mx:Image id="outlineImage" source="@Embed(source='assets/Nokia_6630.png')"/>
        </s:VGroup>        

        <s:VGroup>
            <s:Label text="Sharpness Matrix Image"/>
            <mx:Image id="sharpnessImage" source="@Embed(source='assets/Nokia_6630.png')"/>
        </s:VGroup>        

        <s:VGroup>
            <s:Label text="Brightness Matrix Image"/>
            <mx:Image id="brightnessImage" source="@Embed(source='assets/Nokia_6630.png')"/>
        </s:VGroup>        
    </s:VGroup>        
</s:Application>