Packagemx.core
Classpublic class SpriteAsset
InheritanceSpriteAsset Inheritance FlexSprite Inheritance flash.display.Sprite
ImplementsIBorder, IFlexAsset, IFlexDisplayObject

SpriteAsset is a subclass of the flash.display.Sprite class which represents vector graphic images that you embed in a Flex 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:

  <mx:Style>
      Application
      {
          backgroundImage: Embed(source="Assets.swf", symbol='Logo')
      }
  <mx: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}"/>



Public Properties
 PropertyDefined by
  borderMetrics : EdgeMetrics
[read-only] Returns an EdgeMetrics object for the border that has four properties: left, top, right, and bottom.
SpriteAsset
  measuredHeight : Number
[read-only] The measured height of this object.
SpriteAsset
  measuredWidth : Number
[read-only] The measured width of this object.
SpriteAsset
Public Methods
 MethodDefined by
  
Constructor.
SpriteAsset
  
move(x:Number, y:Number):void
Moves this object to the specified x and y coordinates.
SpriteAsset
  
setActualSize(newWidth:Number, newHeight:Number):void
Sets the actual size of this object.
SpriteAsset
 Inherited
toString():String
Returns a string indicating the location of this object within the hierarchy of DisplayObjects in the Application.
FlexSprite
Property detail
borderMetricsproperty
borderMetrics:EdgeMetrics  [read-only]

Returns an EdgeMetrics object for the border that has four properties: left, top, right, and bottom. The value of each property is equal to the thickness of one side of the border, in pixels.

Implementation
    public function get borderMetrics():EdgeMetrics
measuredHeightproperty 
measuredHeight:Number  [read-only]

The measured height of this object.

This is typically hard-coded for graphical skins because this number is simply the number of pixels in the graphic. For code skins, it can also be hard-coded if you expect to be drawn at a certain size. If your size can change based on properties, you may want to also be an ILayoutManagerClient so a measure() method will be called at an appropriate time, giving you an opportunity to compute a measuredHeight.

Implementation
    public function get measuredHeight():Number
measuredWidthproperty 
measuredWidth:Number  [read-only]

The measured width of this object.

This is typically hard-coded for graphical skins because this number is simply the number of pixels in the graphic. For code skins, it can also be hard-coded if you expect to be drawn at a certain size. If your size can change based on properties, you may want to also be an ILayoutManagerClient so a measure() method will be called at an appropriate time, giving you an opportunity to compute a measuredHeight.

Implementation
    public function get measuredWidth():Number
Constructor detail
SpriteAsset()constructor
public function SpriteAsset()

Constructor.

Method detail
move()method
public function move(x:Number, y:Number):void

Moves this object to the specified x and y coordinates.

Parameters
x:Number — The new x-position for this object.
 
y:Number — The new y-position for this object.
setActualSize()method 
public function setActualSize(newWidth:Number, newHeight:Number):void

Sets the actual size of this object.

This method is mainly for use in implementing the updateDisplayList() method, which is where you compute this object's actual size based on its explicit size, parent-relative (percent) size, and measured size. You then apply this actual size to the object by calling setActualSize().

In other situations, you should be setting properties such as width, height, percentWidth, or percentHeight rather than calling this method.

Parameters
newWidth:Number — The new width for this object.
 
newHeight:Number — The new height for this object.