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.
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>
BaseFilter 
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