Apache Flex 4.16.1 API Reference | All Packages | All Classes | Index | Frames No Frames |
BlurFilter

Package | spark.filters
Class | public class BlurFilter
Inheritance | BlurFilter BaseFilter flash.events.EventDispatcher
Implements | IBitmapFilter

Language Version : | ActionScript 3.0

Product Version : | Flex 4

Runtime Versions : | Flash Player 10, AIR 1.5

The BlurFilter class lets you apply a blur visual effect to display objects. A blur effect softens the details of an image. You can produce blurs that range from a softly unfocused look to a Gaussian blur, a hazy appearance like viewing an image through semi-opaque glass. When the `quality` property of this filter is set to low, the result is a softly unfocused look. When the `quality` property is set to high, it approximates a Gaussian blur filter. 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 new filter, use the constructor `new BlurFilter()`. 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 `cacheAsBitmap` property of the display object is set to `true`. If you remove 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 (`scaleX` and `scaleY` are not set to 100%), the filter effect 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.) If, for example, 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 Show MXML Syntax
Hide MXML Syntax

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

      <s:BlurFilter
        Properties
        blurX="4.0"
        blurY="4.0"
        quality="low"
      />

View the examples

See also

flash.filters.BlurFilter
flash.display.DisplayObject.filters
flash.display.DisplayObject.cacheAsBitmap
flash.display.BitmapData.applyFilter()

Public Properties

| Property | Defined By
--- | --- | ---
|  | blurX : Number The amount of horizontal blur. | BlurFilter
|  | blurY : Number The amount of vertical blur. | BlurFilter
|  | quality : int The number of times to apply the filter. | BlurFilter

Public Methods
Hide Inherited Public Methods
Show Inherited Public Methods

| Method | Defined By
--- | --- | ---
|  | BlurFilter(blurX:Number = 4.0, blurY:Number = 4.0, quality:int = 1) Constructor. | BlurFilter
|  | clone():BitmapFilter Returns a copy of this filter object. | BlurFilter
|  | notifyFilterChanged():void Propagates a change event when the filter has changed. | BaseFilter

Public Constants
Hide Inherited Public Constants
Show Inherited Public Constants

| Constant | Defined By
--- | --- | ---
|  | CHANGE : String = change [static] The string "change". | BaseFilter

Property Detail

blurX | property

`blurX:Number`

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 `4.0`.

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

blurY | property |

`blurY:Number`

Language Version : | ActionScript 3.0

Product Version : | Flex 4

Runtime Versions : | Flash Player 10, AIR 1.5

The amount of vertical 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 `4.0`.

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

quality | property |

`quality:int`

Language Version : | ActionScript 3.0

Product Version : | Flex 4

Runtime Versions : | Flash Player 10, AIR 1.5

The number of times to apply the filter. The default value is `BitmapFilterQuality.LOW`, which is equivalent to applying the filter once. The value `BitmapFilterQuality.MEDIUM` applies the filter twice; the value `BitmapFilterQuality.HIGH` applies it three times. Filters with lower values are rendered more quickly.

For most applications, a quality value of low, medium, or high is sufficient. Although you can use additional numeric values up to 15 to achieve different effects, higher values are rendered more slowly. Instead of increasing the value of quality, you can often get a similar effect, and with faster rendering, by simply increasing the values of the `blurX` and `blurY` properties.

The default value is `"low"`.

Implementation
`public function get quality():int`
`public function set quality(value:int):void`
Constructor Detail

BlurFilter | () | Constructor

`public function BlurFilter(blurX:Number = 4.0, blurY:Number = 4.0, quality:int = 1)`

Language Version : | ActionScript 3.0

Product Version : | Flex 4

Runtime Versions : | Flash Player 10, AIR 1.5

Constructor. The default values create a soft, unfocused image.

Parameters

| `blurX:Number` (default = `4.0`)`` — The amount to blur horizontally. Valid values are from 0 to 255.0 (floating-point value).
| `blurY:Number` (default = `4.0`)`` — The amount to blur vertically. Valid values are from 0 to 255.0 (floating-point value).
| `quality:int` (default = `1`)`` — The number of times to apply the filter. You can specify the quality using the flash.filters.BitmapFilterQuality constants: `flash.filters.BitmapFilterQuality.LOW` `flash.filters.BitmapFilterQuality.MEDIUM` `flash.filters.BitmapFilterQuality.HIGH` High quality approximates a Gaussian blur. For most applications, these three values are sufficient. Although you can use additional numeric values up to 15 to achieve different effects, be aware that higher values are rendered more slowly.

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` — A new BlurFilter instance with all the same properties as the original BlurFilter instance.

Examples
BlurFilterExample.mxml

    <?xml version="1.0"?>
    <!--

      Licensed to the Apache Software Foundation (ASF) under one or more
      contributor license agreements.  See the NOTICE file distributed with
      this work for additional information regarding copyright ownership.
      The ASF licenses this file to You under the Apache License, Version 2.0
      (the "License"); you may not use this file except in compliance with
      the License.  You may obtain a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      See the License for the specific language governing permissions and
      limitations under the License.

    -->
    <!-- filters/examples/BlurFilterExample.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 myBlurFilter:BlurFilter;
         private var color:Number = 0xFF33FF;

         public function createFilters():void {
            myBlurFilter = new BlurFilter(3, 3, BitmapFilterQuality.MEDIUM);
            b1.filters = [myBlurFilter];
         }

      ]]></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:BlurFilter
                        blurX="3"
                        blurY="3"
                        quality="{BitmapFilterQuality.MEDIUM}"/>
                </s:filters>
            </s:Button>

        </s:VGroup>
    </s:Application>

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