Adobe® Flex® 4 Language Reference
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spark.filters 
DropShadowFilter 
Packagespark.filters
Classpublic class DropShadowFilter
InheritanceDropShadowFilter Inheritance BaseDimensionFilter Inheritance BaseFilter Inheritance EventDispatcher Inheritance Object
Implements IBitmapFilter

Language Version: ActionScript 3.0
Product Version: Flex 4
Runtime Versions: Flash Player 10, AIR 1.5

The DropShadowFilter class lets you add a drop shadow to display objects. The shadow algorithm is based on the same box filter that the blur filter uses. You have several options for the style of the drop shadow, including inner or outer shadow and knockout mode. 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 value of 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.) 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 SyntaxexpandedHide MXML Syntax

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

  <s:DropShadowFilter 
    Properties
    alpha="1"
    angle="45"
    color="0xFF0000"
    distance="4"
    hideObject="false"
    inner="false"
  />
  

View the examples

See also



Public Properties
 PropertyDefined By
  alpha : Number
The alpha transparency value for the color.
DropShadowFilter
  angle : Number
The angle of the bevel.
DropShadowFilter
 InheritedblurX : Number
The amount of horizontal blur.
BaseDimensionFilter
 InheritedblurY : Number
The amount of vertical blur.
BaseDimensionFilter
  color : uint
The color of the glow.
DropShadowFilter
 Inheritedconstructor : Object
A reference to the class object or constructor function for a given object instance.
Object
  distance : Number
The offset distance of the bevel.
DropShadowFilter
  hideObject : Boolean
Indicates whether or not the object is hidden.
DropShadowFilter
  inner : Boolean
Specifies whether the glow is an inner glow.
DropShadowFilter
 Inheritedknockout : Boolean
Specifies whether the object has a knockout effect.
BaseDimensionFilter
 Inheritedprototype : Object
[static] A reference to the prototype object of a class or function object.
Object
 Inheritedquality : int
The number of times to apply the filter.
BaseDimensionFilter
 Inheritedstrength : Number
The strength of the imprint or spread.
BaseDimensionFilter
Public Methods
 MethodDefined By
  
DropShadowFilter(distance:Number = 4.0, angle:Number = 45, color:uint = 0, alpha:Number = 1.0, blurX:Number = 4.0, blurY:Number = 4.0, strength:Number = 1.0, quality:int = 1, inner:Boolean = false, knockout:Boolean = false, hideObject:Boolean = false)
Constructor.
DropShadowFilter
 Inherited
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
  
Returns a copy of this filter object.
DropShadowFilter
 Inherited
Dispatches an event into the event flow.
EventDispatcher
 Inherited
Checks whether the EventDispatcher object has any listeners registered for a specific type of event.
EventDispatcher
 Inherited
Indicates whether an object has a specified property defined.
Object
 Inherited
Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.
Object
 Inherited
BaseFilter
 Inherited
Indicates whether the specified property exists and is enumerable.
Object
 Inherited
removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void
Removes a listener from the EventDispatcher object.
EventDispatcher
 Inherited
Sets the availability of a dynamic property for loop operations.
Object
 Inherited
Returns the string representation of this object, formatted according to locale-specific conventions.
Object
 Inherited
Returns the string representation of the specified object.
Object
 Inherited
Returns the primitive value of the specified object.
Object
 Inherited
Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.
EventDispatcher
Events
 Event Summary Defined By
 Inherited[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active.EventDispatcher
 Inherited[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive.EventDispatcher
Public Constants
 ConstantDefined By
 InheritedCHANGE : 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

angle

property 
angle:Number

Language Version: ActionScript 3.0
Product Version: Flex 4
Runtime Versions: Flash Player 10, AIR 1.5

The angle of the bevel. Valid values are from 0 to 360°. The angle value represents the angle of the theoretical light source falling on the object and determines the placement of the effect relative to the object. If the distance property is set to 0, the effect is not offset from the object and, therefore, the angle property has no effect.

The default value is 45.



Implementation
    public function get angle():Number
    public function set angle(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

distance

property 
distance:Number

Language Version: ActionScript 3.0
Product Version: Flex 4
Runtime Versions: Flash Player 10, AIR 1.5

The offset distance of the bevel. Valid values are in pixels (floating point).

The default value is 4.



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

hideObject

property 
hideObject:Boolean

Language Version: ActionScript 3.0
Product Version: Flex 4
Runtime Versions: Flash Player 10, AIR 1.5

Indicates whether or not the object is hidden. The value true indicates that the object itself is not drawn; only the shadow is visible. The default is false, meaning that the object is shown.

The default value is false.



Implementation
    public function get hideObject():Boolean
    public function set hideObject(value:Boolean):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 that creates 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

DropShadowFilter

()Constructor
public function DropShadowFilter(distance:Number = 4.0, angle:Number = 45, color:uint = 0, alpha:Number = 1.0, blurX:Number = 4.0, blurY:Number = 4.0, strength:Number = 1.0, quality:int = 1, inner:Boolean = false, knockout:Boolean = false, hideObject:Boolean = false)

Language Version: ActionScript 3.0
Product Version: Flex 4
Runtime Versions: Flash Player 10, AIR 1.5

Constructor.

Parameters
distance:Number (default = 4.0) — Offset distance for the shadow, in pixels.
 
angle:Number (default = 45) — Angle of the shadow, 0 to 360 degrees (floating point).
 
color:uint (default = 0) — Color of the shadow, in hexadecimal format 0xRRGGBB. The default value is 0x000000.
 
alpha:Number (default = 1.0) — Alpha transparency value for the shadow color. Valid values are 0.0 to 1.0. For example, .25 sets a transparency value of 25%.
 
blurX:Number (default = 4.0) — Amount of horizontal blur. Valid values are 0 to 255.0 (floating point).
 
blurY:Number (default = 4.0) — Amount of vertical blur. Valid values are 0 to 255.0 (floating point).
 
strength:Number (default = 1.0) — The strength of the imprint or spread. The higher the value, the more color is imprinted and the stronger the contrast between the shadow and the background. Valid values are 0 to 255.0.
 
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 about these values, see the quality property description.

 
inner:Boolean (default = false) — Indicates whether or not the shadow is an inner shadow. A value of true specifies an inner shadow. A value of false specifies an outer shadow (a shadow around the outer edges of the object).
 
knockout:Boolean (default = false) — Applies a knockout effect (true), which effectively makes the object's fill transparent and reveals the background color of the document.
 
hideObject:Boolean (default = false) — Indicates whether or not the object is hidden. A value of true indicates that the object itself is not drawn; only the shadow is visible.

See also

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 DropShadowFilter instance with all the properties of the original DropShadowFilter instance.
DropShadowFilterExample.mxml
<?xml version="1.0"?>
<!-- filters/examples/DropShadowFilterExample.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 myDropShadowFilter:DropShadowFilter;  
     private var color:Number = 0xFF33FF;
  
     public function createFilters():void {        
        myDropShadowFilter = new DropShadowFilter(15, 45, 
            color, 0.8, 8, 8, 0.65, BitmapFilterQuality.MEDIUM, false, false);
        b1.filters = [myDropShadowFilter];
     }
  
  ]]></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:DropShadowFilter 
                    distance="15" 
                    angle="45" 
                    color="0xFF33FF" 
                    alpha=".8" 
                    blurX="8" 
                    blurY="8" 
                    strength=".65" 
                    quality="{BitmapFilterQuality.MEDIUM}"
                    inner="false" 
                    knockout="false"/>
            </s:filters>
        </s:Button>
        
    </s:VGroup>        
</s:Application>