BitmapAsset is a subclass of the flash.display.Bitmap class
which represents bitmap images that you embed in a Flex application.
It implements the IFlexDisplayObject interface, which makes it
possible for an embedded bitmap image to be displayed in an Image control,
or to be used as a container background or a component skin.
The bitmap image that you're embedding can be in a JPEG, GIF,
or PNG file.
You can also embed a bitmap symbol that is in a SWF file produced
by Flash.
In each of these cases, the MXML compiler autogenerates a class
that extends BitmapAsset to represent the embedded bitmap image.
You don't generally have to use the BitmapAsset class directly
when you write a Flex application.
For example, you can embed a GIF file and display the image
in an Image control by writing the gollowing:
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 bitmap image in ActionScript, you declare a variable
of type Class, and put [Embed] metadata on it.
For example, you embed a GIF file like this:
[Bindable]
[Embed(source="Logo.gif")]
private var logoClass:Class;
The MXML compiler sees the .gif extension, transcodes the GIF data
into the bitmap format that the player uses, autogenerates
a subclass of the BitmapAsset class, and sets your variable
to be a reference to this autogenerated class.
You can then use this class reference to create instances of the
BitmapAsset using the new operator, and you can use
APIs of the BitmapAsset class on them:
var logo:BitmapAsset = BitmapAsset(new logoClass());
logo.bitmapData.noise(4);
However, you rarely need to create BitmapAsset 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 image in an Image control, you can
set the Image's source property to logoClass.
In MXML you could do this as follows:
Specifies the desired layout direction for an element: one of LayoutDirection.LTR
(left to right), LayoutDirection.RTL (right to left), or null (inherit).
Specifies the desired layout direction for an element: one of LayoutDirection.LTR
(left to right), LayoutDirection.RTL (right to left), or null (inherit).
This property is typically backed by an inheriting style. If null,
the layoutDirection style will be set to undefined.
Classes like GraphicElement, which implement ILayoutDirectionElement but do not
support styles, must additionally support a null value for this property
which means the layoutDirection must be inherited from its parent.
Implementation public function get layoutDirection():String public function set layoutDirection(value:String):void
measuredHeight
property
measuredHeight:Number [read-only]
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
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
measuredWidth
property
measuredWidth:Number [read-only]
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
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
BitmapAsset
()
Constructor
public function BitmapAsset(bitmapData:BitmapData = null, pixelSnapping:String = auto, smoothing:Boolean = false)
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
Constructor.
Parameters
bitmapData:BitmapData (default = null) — The data for the bitmap image.
pixelSnapping:String (default = auto) — Whether or not the bitmap is snapped
to the nearest pixel.
smoothing:Boolean (default = false) — Whether or not the bitmap is smoothed when scaled.
Method Detail
invalidateLayoutDirection
()
method
public function invalidateLayoutDirection():void
Language Version :
ActionScript 3.0
Product Version :
Flex 4.1
Runtime Versions :
Flash Player 10, AIR 1.5
An element must call this method when its layoutDirection changes or
when its parent's layoutDirection changes.
If they differ, this method is responsible for mirroring the element’s contents
and for updating the element’s post-layout transform so that descendants inherit
a mirrored coordinate system. IVisualElements typically implement
mirroring by using postLayoutTransformOffsets to scale the X axis by -1 and
to translate the x coordinate of the origin by the element's width.
The net effect of this "mirror" transform is to reverse the direction
in which the X axis increases without changing the element's location
relative to its parent's origin.
move
()
method
public function move(x:Number, y:Number):void
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
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
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
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.
FlexBitmap 
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