spark.filters

# ConvolutionFilter - AS3 Flex

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 Show MXML Syntax
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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"
     />

View the examples

More examples

Using filters with chart controls

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

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 Propagates a change event when the filter has changed. | 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
--- | --- | ---

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
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    <?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>

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