Package	mx.core
Class	public class SpriteAsset
Inheritance	SpriteAsset FlexSprite Sprite DisplayObjectContainer InteractiveObject DisplayObject EventDispatcher Object
Implements	IFlexAsset, IFlexDisplayObject, IBorder
Subclasses	DefaultDragImage

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

SpriteAsset is a subclass of the flash.display.Sprite class which represents vector graphic images that you embed in an application. It implements the IFlexDisplayObject interface, which makes it possible for an embedded vector graphic image to be displayed in an Image control, or to be used as a container background or a component skin.

The vector graphic image that you're embedding can be in an SVG file. You can also embed a sprite symbol that is in a SWF file produced by Flash. In both cases, the MXML compiler autogenerates a class that extends SpriteAsset to represent the embedded vector graphic image.

You don't generally have to use the SpriteAsset class directly when you write a Flex application. For example, you can embed a sprite symbol from a SWF file and display it in an Image control by writing the following:

  <mx:Image id="logo" source="@Embed(source='Assets.swf', symbol='Logo')"/>

Or use it as the application's background image in CSS syntax by writing the following:

  <fx:Style>
      @namespace mx "library://ns.adobe.com/flex/mx"
      mx|Application {
          backgroundImage: Embed(source="Assets.swf", symbol='Logo')
      }
  <fx:Style/>

without having to understand that the MXML compiler has created a subclass of BitmapAsset for you.

However, it may be useful to understand what is happening at the ActionScript level. To embed a vector graphic image in ActionScript, you declare a variable of type Class, and put [Embed] metadata on it. For example, you embed a sprite symbol from a SWF file like this:

  [Bindable]
  [Embed(source="Assets.swf", symbol="Logo")]
  private var logoClass:Class;

The MXML compiler notices that the Logo symbol in Assets.swf is a sprite, autogenerates a subclass of the SpriteAsset class to represent it, and sets your variable to be a reference to this autogenerated class. You can then use this class reference to create instances of the SpriteAsset using the new operator, and use APIs of the Sprite class on them:

  var logo:SpriteAsset = SpriteAsset(new logoClass());
  logo.rotation=45;

However, you rarely need to create SpriteAsset instances yourself because image-related properties and styles can simply be set to an image-producing class, and components will create image instances as necessary. For example, to display this vector graphic image in an Image control, you can set the Image's source property to logoClass. In MXML you could do this as follows:

  <mx:Image id="logo" source="{logoClass}"/>

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