The DisplayObject class supports basic functionality like the x and y position of an object, as well as more advanced properties of the object such as its transformation matrix.
DisplayObject is an abstract base class; therefore, you cannot call
DisplayObject directly. Invoking new DisplayObject() throws an
ArgumentError exception.
All display objects inherit from the DisplayObject class.
The DisplayObject class itself does not include any APIs for rendering content onscreen. For that reason, if you want create a custom subclass of the DisplayObject class, you will want to extend one of its subclasses that do have APIs for rendering content onscreen, such as the Shape, Sprite, Bitmap, SimpleButton, TextField, or MovieClip class.
The DisplayObject class contains several broadcast events. Normally, the
target of any particular event is a specific DisplayObject instance. For
example, the target of an added event is the specific
DisplayObject instance that was added to the display list. Having a single
target restricts the placement of event listeners to that target and in
some cases the target's ancestors on the display list. With broadcast
events, however, the target is not a specific DisplayObject instance, but
rather all DisplayObject instances, including those that are not on the
display list. This means that you can add a listener to any DisplayObject
instance to listen for broadcast events. In addition to the broadcast
events listed in the DisplayObject class's Events table, the DisplayObject
class also inherits two broadcast events from the EventDispatcher class:
activate and deactivate.
Some properties previously used in the ActionScript 1.0 and 2.0
MovieClip, TextField, and Button classes(such as _alpha,
_height, _name, _width,
_x, _y, and others) have equivalents in the
ActionScript 3.0 DisplayObject class that are renamed so that they no
longer begin with the underscore(_) character.
For more information, see the "Display Programming" chapter of the ActionScript 3.0 Developer's Guide.
BlendMode.NORMAL.
The blendMode property affects each pixel of the display
object. Each pixel is composed of three constituent colors(red, green,
and blue), and each constituent color has a value between 0x00 and 0xFF.
Flash Player or Adobe AIR compares each constituent color of one pixel in
the movie clip with the corresponding color of the pixel in the
background. For example, if blendMode is set to
BlendMode.LIGHTEN, Flash Player or Adobe AIR compares the red
value of the display object with the red value of the background, and uses
the lighter of the two as the value for the red component of the displayed
color.
The following table describes the blendMode settings. The
BlendMode class defines string values you can use. The illustrations in
the table show blendMode values applied to a circular display
object(2) superimposed on another display object(1).
true, NME will use the software renderer to cache
an internal bitmap representation of the display object. For native targets,
this is often much slower than the default hardware renderer. When you
are using the Flash target, this caching may increase performance for display
objects that contain complex vector content.
All vector data for a display object that has a cached bitmap is drawn
to the bitmap instead of the main display. If
cacheAsBitmapMatrix is null or unsupported, the bitmap is
then copied to the main display as unstretched, unrotated pixels snapped
to the nearest pixel boundaries. Pixels are mapped 1 to 1 with the parent
object. If the bounds of the bitmap change, the bitmap is recreated
instead of being stretched.
If cacheAsBitmapMatrix is non-null and supported, the
object is drawn to the off-screen bitmap using that matrix and the
stretched and/or rotated results of that rendering are used to draw the
object to the main display.
No internal bitmap is created unless the cacheAsBitmap
property is set to true.
After you set the cacheAsBitmap property to
true, the rendering does not change, however the display
object performs pixel snapping automatically. The animation speed can be
significantly faster depending on the complexity of the vector content.
The cacheAsBitmap property is automatically set to
true whenever you apply a filter to a display object(when
its filter array is not empty), and if a display object has a
filter applied to it, cacheAsBitmap is reported as
true for that display object, even if you set the property to
false. If you clear all filters for a display object, the
cacheAsBitmap setting changes to what it was last set to.
A display object does not use a bitmap even if the
cacheAsBitmap property is set to true and
instead renders from vector data in the following cases:
The cacheAsBitmap property is best used with movie clips
that have mostly static content and that do not scale and rotate
frequently. With such movie clips, cacheAsBitmap can lead to
performance increases when the movie clip is translated(when its x
and y position is changed).
Filters can be applied in Flash Professional at design time, or at run
time by using ActionScript code. To apply a filter by using ActionScript,
you must make a temporary copy of the entire filters array,
modify the temporary array, then assign the value of the temporary array
back to the filters array. You cannot directly add a new
filter object to the filters array.
To add a filter by using ActionScript, perform the following steps
(assume that the target display object is named
myDisplayObject):
myDisplayObject.filters array
to a temporary array, such as one named myFilters.myFilters temporary
array.myDisplayObject.filters array.If the filters array is undefined, you do not need to use
a temporary array. Instead, you can directly assign an array literal that
contains one or more filter objects that you create. The first example in
the Examples section adds a drop shadow filter by using code that handles
both defined and undefined filters arrays.
To modify an existing filter object, you must use the technique of
modifying a copy of the filters array:
filters array to a temporary
array, such as one named myFilters.myFilters. For example, to set the quality property of the
first filter in the array, you could use the following code:
myFilters0.quality = 1;filters
array.At load time, if a display object has an associated filter, it is marked to cache itself as a transparent bitmap. From this point forward, as long as the display object has a valid filter list, the player caches the display object as a bitmap. This source bitmap is used as a source image for the filter effects. Each display object usually has two bitmaps: one with the original unfiltered source display object and another for the final image after filtering. The final image is used when rendering. As long as the display object does not change, the final image does not need updating.
The nme.filters package includes classes for filters. For example, to create a DropShadow filter, you would write:
height property, the scaleY property
is adjusted accordingly, as shown in the following code:
Except for TextField and Video objects, a display object with no
content(such as an empty sprite) has a height of 0, even if you try to
set height to a different value.
loaderInfo property
is defined only for the root display object of a SWF file or for a loaded
Bitmap(not for a Bitmap that is drawn with ActionScript). To find the
loaderInfo object associated with the SWF file that contains
a display object named myDisplayObject, use
myDisplayObject.root.loaderInfo.
A large SWF file can monitor its download by calling
this.root.loaderInfo.addEventListener(Event.COMPLETE,
func).
mask
object. To ensure that masking works when the Stage is scaled, the
mask display object must be in an active part of the display
list. The mask object itself is not drawn. Set
mask to null to remove the mask.
To be able to scale a mask object, it must be on the display list. To
be able to drag a mask Sprite object(by calling its
startDrag() method), it must be on the display list. To call
the startDrag() method for a mask sprite based on a
mouseDown event being dispatched by the sprite, set the
sprite's buttonMode property to true.
When display objects are cached by setting the
cacheAsBitmap property to true an the
cacheAsBitmapMatrix property to a Matrix object, both the
mask and the display object being masked must be part of the same cached
bitmap. Thus, if the display object is cached, then the mask must be a
child of the display object. If an ancestor of the display object on the
display list is cached, then the mask must be a child of that ancestor or
one of its descendents. If more than one ancestor of the masked object is
cached, then the mask must be a descendent of the cached container closest
to the masked object in the display list.
Note: A single mask object cannot be used to mask
more than one calling display object. When the mask is
assigned to a second display object, it is removed as the mask of the
first object, and that object's mask property becomes
null.
Note: For a DisplayObject that has been rotated, the returned x coordinate will reflect the non-rotated object.
Note: For a DisplayObject that has been rotated, the returned y coordinate will reflect the non-rotated object.
getChildByName() method of the display object
container.
If set to a number value, the surface is opaque(not transparent) with
the RGB background color that the number specifies. If set to
null(the default value), the display object has a
transparent background.
The opaqueBackground property is intended mainly for use
with the cacheAsBitmap property, for rendering optimization.
For display objects in which the cacheAsBitmap property is
set to true, setting opaqueBackground can improve rendering
performance.
The opaque background region is not matched when calling the
hitTestPoint() method with the shapeFlag
parameter set to true.
The opaque background region does not respond to mouse events.
parent property to specify a relative path to
display objects that are above the current display object in the display
list hierarchy.
You can use parent to move up multiple levels in the
display list as in the following:
root property
is the top-most display object in the portion of the display list's tree
structure represented by that SWF file. For a Bitmap object representing a
loaded image file, the root property is the Bitmap object
itself. For the instance of the main class of the first SWF file loaded,
the root property is the display object itself. The
root property of the Stage object is the Stage object itself.
The root property is set to null for any display
object that has not been added to the display list, unless it has been
added to a display object container that is off the display list but that
is a child of the top-most display object in a loaded SWF file.
For example, if you create a new Sprite object by calling the
Sprite() constructor method, its root property
is null until you add it to the display list(or to a display
object container that is off the display list but that is a child of the
top-most display object in a SWF file).
For a loaded SWF file, even though the Loader object used to load the
file may not be on the display list, the top-most display object in the
SWF file has its root property set to itself. The Loader
object does not have its root property set until it is added
as a child of a display object for which the root property is
set.
my_video.rotation = 450
is the same as my_video.rotation = 90.null,
the entire display object is scaled normally when any scale transformation
is applied.
When you define the scale9Grid property, the display
object is divided into a grid with nine regions based on the
scale9Grid rectangle, which defines the center region of the
grid. The eight other regions of the grid are the following areas:
You can think of the eight regions outside of the center(defined by the rectangle) as being like a picture frame that has special rules applied to it when scaled.
When the scale9Grid property is set and a display object
is scaled, all text and gradients are scaled normally; however, for other
types of objects the following rules apply:
If a display object is rotated, all subsequent scaling is normal(and
the scale9Grid property is ignored).
For example, consider the following display object and a rectangle that
is applied as the display object's scale9Grid:
A common use for setting scale9Grid is to set up a display
object to be used as a component, in which edge regions retain the same
width when the component is scaled.
Scaling the local coordinate system changes the x and
y property values, which are defined in whole pixels.
Scaling the local coordinate system changes the x and
y property values, which are defined in whole pixels.
x and y properties
of the scrollRect object.
The properties of the scrollRect Rectangle object use the
display object's coordinate space and are scaled just like the overall
display object. The corner bounds of the cropped window on the scrolling
display object are the origin of the display object(0,0) and the point
defined by the width and height of the rectangle. They are not centered
around the origin, but use the origin to define the upper-left corner of
the area. A scrolled display object always scrolls in whole pixel
increments.
You can scroll an object left and right by setting the x
property of the scrollRect Rectangle object. You can scroll
an object up and down by setting the y property of the
scrollRect Rectangle object. If the display object is rotated
90° and you scroll it left and right, the display object actually scrolls
up and down.
stage property of each
display object refers to the same Stage object(even if the display object
belongs to a loaded SWF file).
If a display object is not added to the display list, its
stage property is set to null.
concatenatedMatrix, concatenatedColorTransform,
and pixelBounds) - are described in the entry for the
Transform class.
Each of the transform object's properties is itself an object. This concept is important because the only way to set new values for the matrix or colorTransform objects is to create a new object and copy that object into the transform.matrix or transform.colorTransform property.
For example, to increase the tx value of a display
object's matrix, you must make a copy of the entire matrix object, then
copy the new object into the matrix property of the transform object:
var myMatrix:Matrix =
myDisplayObject.transform.matrix; myMatrix.tx += 10;
myDisplayObject.transform.matrix = myMatrix; You cannot directly set the tx property. The following
code has no effect on myDisplayObject:
myDisplayObject.transform.matrix.tx +=
10; You can also copy an entire transform object and assign it to another
display object's transform property. For example, the following code
copies the entire transform object from myOldDisplayObj to
myNewDisplayObj:
myNewDisplayObj.transform = myOldDisplayObj.transform;
The resulting display object, myNewDisplayObj, now has the
same values for its matrix, color transform, and pixel bounds as the old
display object, myOldDisplayObj.
Note that AIR for TV devices use hardware acceleration, if it is available, for color transforms.
visible=false for an
InteractiveObject instance, it cannot be clicked.width property, the scaleX property
is adjusted accordingly, as shown in the following code:
Except for TextField and Video objects, a display object with no
content(such as an empty sprite) has a width of 0, even if you try to set
width to a different value.
type The type of event.useCapture Determines whether the listener works in the capture phase or the target and bubbling phases. If useCapture is set to true, the listener processes the event only during the capture phase and not in the target or bubbling phase. If useCapture is false, the listener processes the event only during the target or bubbling phase. To listen for the event in all three phases, call addEventListener twice, once with useCapture set to true, then again with useCapture set to false.priority The priority level of the event listener. The priority is designated by a signed 32-bit integer. The higher the number, the higher the priority. All listeners with priority n are processed before listeners of priority n-1. If two or more listeners share the same priority, they are processed in the order in which they were added. The default priority is 0.useWeakReference Determines whether the reference to the listener is strong or weak. A strong reference(the default) prevents your listener from being garbage-collected. A weak reference does not. Class-level member functions are not subject to garbage collection, so you can set useWeakReference to true for class-level member functions without subjecting them to garbage collection. If you set useWeakReference to true for a listener that is a nested inner function, the function will be garbage-collected and no longer persistent. If you create references to the inner function(save it in another variable) then it is not garbage-collected and stays persistent.
ArgumentError The listener specified is not a function.After you successfully register an event listener, you cannot change
its priority through additional calls to addEventListener().
To change a listener's priority, you must first call
removeListener(). Then you can register the listener again
with the new priority level.
Keep in mind that after the listener is registered, subsequent calls to
addEventListener() with a different type or
useCapture value result in the creation of a separate
listener registration. For example, if you first register a listener with
useCapture set to true, it listens only during
the capture phase. If you call addEventListener() again using
the same listener object, but with useCapture set to
false, you have two separate listeners: one that listens
during the capture phase and another that listens during the target and
bubbling phases.
You cannot register an event listener for only the target phase or the bubbling phase. Those phases are coupled during registration because bubbling applies only to the ancestors of the target node.
If you no longer need an event listener, remove it by calling
removeEventListener(), or memory problems could result. Event
listeners are not automatically removed from memory because the garbage
collector does not remove the listener as long as the dispatching object
exists(unless the useWeakReference parameter is set to
true).
Copying an EventDispatcher instance does not copy the event listeners attached to it.(If your newly created node needs an event listener, you must attach the listener after creating the node.) However, if you move an EventDispatcher instance, the event listeners attached to it move along with it.
If the event listener is being registered on a node while an event is being processed on this node, the event listener is not triggered during the current phase but can be triggered during a later phase in the event flow, such as the bubbling phase.
If an event listener is removed from a node while an event is being processed on the node, it is still triggered by the current actions. After it is removed, the event listener is never invoked again(unless registered again for future processing).
event The Event object that is dispatched into the event flow. If the event is being redispatched, a clone of the event is created automatically. After an event is dispatched, its target property cannot be changed, so you must create a new copy of the event for redispatching to work.true if the event was successfully dispatched. A value of false indicates failure or that preventDefault() was called on the event.Error The event dispatch recursion limit has been reached.dispatchEvent() method
is called.
targetCoordinateSpace The display object that defines the coordinate system to use.targetCoordinateSpace object's coordinate system.targetCoordinateSpace object.
Consider the following code, which shows how the rectangle returned can
vary depending on the targetCoordinateSpace parameter that
you pass to the method:
Note: Use the localToGlobal() and
globalToLocal() methods to convert the display object's local
coordinates to display coordinates, or display coordinates to local
coordinates, respectively.
The getBounds() method is similar to the
getRect() method; however, the Rectangle returned by the
getBounds() method includes any strokes on shapes, whereas
the Rectangle returned by the getRect() method does not. For
an example, see the description of the getRect() method.
targetCoordinateSpace The display object that defines the coordinate system to use.targetCoordinateSpace object's coordinate system.targetCoordinateSpace
parameter, excluding any strokes on shapes. The values that the
getRect() method returns are the same or smaller than those
returned by the getBounds() method.
Note: Use localToGlobal() and
globalToLocal() methods to convert the display object's local
coordinates to Stage coordinates, or Stage coordinates to local
coordinates, respectively.
point An object created with the Point class. The Point object specifies the x and y coordinates as properties.point object from the Stage(global) coordinates
to the display object's(local) coordinates.
To use this method, first create an instance of the Point class. The
x and y values that you assign represent global coordinates
because they relate to the origin(0,0) of the main display area. Then
pass the Point instance as the parameter to the
globalToLocal() method. The method returns a new Point object
with x and y values that relate to the origin of the display
object instead of the origin of the Stage.
type The type of event.true if a listener of the specified type is registered; false otherwise.willTrigger().
The difference between hasEventListener() and
willTrigger() is that hasEventListener()
examines only the object to which it belongs, whereas
willTrigger() examines the entire event flow for the event
specified by the type parameter.
When hasEventListener() is called from a LoaderInfo
object, only the listeners that the caller can access are considered.
obj The display object to test against.true if the bounding boxes of the display objects intersect; false if not.obj display object.
x The x coordinate to test against this object.y The y coordinate to test against this object.shapeFlag Whether to check against the actual pixels of the object (true) or the bounding box (false).true if the display object overlaps or intersects with the specified point; false otherwise.x and y parameters. The
x and y parameters specify a point in the
coordinate space of the Stage, not the display object container that
contains the display object(unless that display object container is the
Stage).
point The name or identifier of a point created with the Point class, specifying the x and y coordinates as properties.point object from the display object's(local)
coordinates to the Stage(global) coordinates.
This method allows you to convert any given x and y coordinates from values that are relative to the origin(0,0) of a specific display object(local coordinates) to values that are relative to the origin of the Stage(global coordinates).
To use this method, first create an instance of the Point class. The x and y values that you assign represent local coordinates because they relate to the origin of the display object.
You then pass the Point instance that you created as the parameter to
the localToGlobal() method. The method returns a new Point
object with x and y values that relate to the origin of the
Stage instead of the origin of the display object.
type The type of event.useCapture Specifies whether the listener was registered for the capture phase or the target and bubbling phases. If the listener was registered for both the capture phase and the target and bubbling phases, two calls to removeEventListener() are required to remove both, one call with useCapture() set to true, and another call with useCapture() set to false.type The type of event.true if a listener of the specified type will be triggered; false otherwise.true if an event listener is triggered during any
phase of the event flow when an event of the specified type is dispatched
to this EventDispatcher object or any of its descendants.
The difference between the hasEventListener() and the
willTrigger() methods is that hasEventListener()
examines only the object to which it belongs, whereas the
willTrigger() method examines the entire event flow for the
event specified by the type parameter.
When willTrigger() is called from a LoaderInfo object,
only the listeners that the caller can access are considered.
alphaset to 0 are active, even though they are invisible.