ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Filtering display objects
import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.filters.DropShadowFilter;
// Create a bitmapData object and render it to screen
var myBitmapData:BitmapData = new BitmapData(100,100,false,0xFFFF3300);
var myDisplayObject:Bitmap = new Bitmap(myBitmapData);
addChild(myDisplayObject);
// Create a DropShadowFilter instance.
var dropShadow:DropShadowFilter = new DropShadowFilter();
// Create the filters array, adding the filter to the array by passing it as
// a parameter to the Array() constructor.
var filtersArray:Array = new Array(dropShadow);
// Assign the filters array to the display object to apply the filter.
myDisplayObject.filters = filtersArray;
If you want to assign multiple filters to the object, simply add all the filters to the Array instance before assigning it to
the filters property. You can add multiple objects to an Array by passing them as parameters to its constructor. For
example, this code applies a bevel filter and a glow filter to the previously created display object:
import flash.filters.BevelFilter;
import flash.filters.GlowFilter;
// Create the filters and add them to an array.
var bevel:BevelFilter = new BevelFilter();
var glow:GlowFilter = new GlowFilter();
var filtersArray:Array = new Array(bevel, glow);
// Assign the filters array to the display object to apply the filter.
myDisplayObject.filters = filtersArray;
When you’re creating the array containing the filters, you can create it using the new Array() constructor (as shown
in the previous examples) or you can use Array literal syntax, wrapping the filters in square brackets ([]). For instance,
this line of code:
var filters:Array = new Array(dropShadow, blur);
does the same thing as this line of code:
var filters:Array = [dropShadow, blur];
If you apply multiple filters to display objects, they are applied in a cumulative, sequential manner. For example, if a
filters array has two elements, a bevel filter added first and a drop shadow filter added second, the drop shadow filter
is applied to both the bevel filter and the display object. This is because of the drop shadow filter’s second position in
the filters array. If you want to apply filters in a noncumulative manner, apply each filter to a new copy of the display
object.
If you’re only assigning one or a few filters to a display object, you can create the filter instance and assign it to the
object in a single statement. For example, the following line of code applies a blur filter to a display object called
myDisplayObject:
myDisplayObject.filters = [new BlurFilter()];
The previous code creates an Array instance using Array literal syntax (square braces), creates a BlurFilter instance as
an element in the Array, and assigns that Array to the filters property of the display object named
myDisplayObject.
Last updated 6/6/2012
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