class DisplayObject
package openfl.display
extends EventDispatcher
implements IBitmapDrawable
extended by Bitmap, DirectRenderer, InteractiveObject, Shape, Tilemap, Video
Available on all platforms
The DisplayObject class is the base class for all objects that can be placed on the display list. The display list manages all objects displayed in openfl. Use the DisplayObjectContainer class to arrange the display objects in the display list. DisplayObjectContainer objects can have child display objects, while other display objects, such as Shape and TextField objects, are "leaf" nodes that have only parents and siblings, no children.
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.
@event added Dispatched when a display object is added to the
display list. The following methods trigger this
event:
`DisplayObjectContainer.addChild()`,
`DisplayObjectContainer.addChildAt()`.
@event addedToStage Dispatched when a display object is added to the on
stage display list, either directly or through the
addition of a sub tree in which the display object
is contained. The following methods trigger this
event:
`DisplayObjectContainer.addChild()`,
`DisplayObjectContainer.addChildAt()`.
@event enterFrame [broadcast event] Dispatched when the playhead is
entering a new frame. If the playhead is not
moving, or if there is only one frame, this event
is dispatched continuously in conjunction with the
frame rate. This event is a broadcast event, which
means that it is dispatched by all display objects
with a listener registered for this event.
@event exitFrame [broadcast event] Dispatched when the playhead is
exiting the current frame. All frame scripts have
been run. If the playhead is not moving, or if
there is only one frame, this event is dispatched
continuously in conjunction with the frame rate.
This event is a broadcast event, which means that
it is dispatched by all display objects with a
listener registered for this event.
@event frameConstructed [broadcast event] Dispatched after the constructors
of frame display objects have run but before frame
scripts have run. If the playhead is not moving, or
if there is only one frame, this event is
dispatched continuously in conjunction with the
frame rate. This event is a broadcast event, which
means that it is dispatched by all display objects
with a listener registered for this event.
@event removed Dispatched when a display object is about to be
removed from the display list. Two methods of the
DisplayObjectContainer class generate this event:
`removeChild()` and
`removeChildAt()`.
The following methods of a
DisplayObjectContainer object also generate this
event if an object must be removed to make room for
the new object: `addChild()`,
`addChildAt()`, and
`setChildIndex()`.
@event removedFromStage Dispatched when a display object is about to be
removed from the display list, either directly or
through the removal of a sub tree in which the
display object is contained. Two methods of the
DisplayObjectContainer class generate this event:
`removeChild()` and
`removeChildAt()`.
The following methods of a
DisplayObjectContainer object also generate this
event if an object must be removed to make room for
the new object: `addChild()`,
`addChildAt()`, and
`setChildIndex()`.
@event render [broadcast event] Dispatched when the display list
is about to be updated and rendered. This event
provides the last opportunity for objects listening
for this event to make changes before the display
list is rendered. You must call the
`invalidate()` method of the Stage
object each time you want a `render`
event to be dispatched. `Render` events
are dispatched to an object only if there is mutual
trust between it and the object that called
`Stage.invalidate()`. This event is a
broadcast event, which means that it is dispatched
by all display objects with a listener registered
for this event.
**Note: **This event is not dispatched if the
display is not rendering. This is the case when the
content is either minimized or obscured.
Variables
read onlywrite onlyalpha:Float
Indicates the alpha transparency value of the object specified. Valid
values are 0(fully transparent) to 1(fully opaque). The default value is
1. Display objects with alpha
set to 0 are active,
even though they are invisible.
A value from the BlendMode class that specifies which blend mode to use. A
bitmap can be drawn internally in two ways. If you have a blend mode
enabled or an external clipping mask, the bitmap is drawn by adding a
bitmap-filled square shape to the vector render. If you attempt to set
this property to an invalid value, Flash runtimes set the value to
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).
read onlywrite onlycacheAsBitmap:Bool
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 bitmap is too large. In AIR 1.5 and Flash Player 10, the maximum size for a bitmap image is 8,191 pixels in width or height, and the total number of pixels cannot exceed 16,777,215 pixels.(So, if a bitmap image is 8,191 pixels wide, it can only be 2,048 pixels high.) In Flash Player 9 and earlier, the limitation is is 2880 pixels in height and 2,880 pixels in width.
- The bitmap fails to allocate(out of memory error).
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).
read onlywrite onlyfilters:Array<BitmapFilter>
An indexed array that contains each filter object currently associated with the display object. The openfl.filters package contains several classes that define specific filters you can use.
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
):
- Create a new filter object by using the constructor method of your chosen filter class.
- Assign the value of the
myDisplayObject.filters
array to a temporary array, such as one namedmyFilters
. - Add the new filter object to the
myFilters
temporary array. - Assign the value of the temporary array to the
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:
- Assign the value of the
filters
array to a temporary array, such as one namedmyFilters
. - Modify the property by using the temporary array,
myFilters
. For example, to set the quality property of the first filter in the array, you could use the following code:myFilters[0].quality = 1;
- Assign the value of the temporary array to the
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 openfl.filters package includes classes for filters. For example, to create a DropShadow filter, you would write:
Throws:
ArgumentError | When |
---|---|
ArgumentError | When |
ArgumentError | When |
ArgumentError | When |
read onlywrite onlyheight:Float
Indicates the height of the display object, in pixels. The height is
calculated based on the bounds of the content of the display object. When
you set the 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.
read onlywrite onlyloaderInfo:LoaderInfo
Returns a LoaderInfo object containing information about loading the file
to which this display object belongs. The 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)
.
read onlywrite onlymask:DisplayObject
The calling display object is masked by the specified 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
.
read onlywrite onlymouseX:Float
Indicates the x coordinate of the mouse or user input device position, in pixels.
Note: For a DisplayObject that has been rotated, the returned x coordinate will reflect the non-rotated object.
read onlywrite onlymouseY:Float
Indicates the y coordinate of the mouse or user input device position, in pixels.
Note: For a DisplayObject that has been rotated, the returned y coordinate will reflect the non-rotated object.
read onlywrite onlyname:String
Indicates the instance name of the DisplayObject. The object can be
identified in the child list of its parent display object container by
calling the getChildByName()
method of the display object
container.
Throws:
IllegalOperationError | If you are attempting to set this property on an object that was placed on the timeline in the Flash authoring tool. |
---|
Specifies whether the display object is opaque with a certain background color. A transparent bitmap contains alpha channel data and is drawn transparently. An opaque bitmap has no alpha channel(and renders faster than a transparent bitmap). If the bitmap is opaque, you specify its own background color to use.
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.
read onlyparent:DisplayObjectContainer
Indicates the DisplayObjectContainer object that contains this display
object. Use the 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:
Throws:
SecurityError | The parent display object belongs to a security
sandbox to which you do not have access. You can
avoid this situation by having the parent movie call
the |
---|
read onlywrite onlyroot:DisplayObject
For a display object in a loaded SWF file, the 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.
read onlywrite onlyrotation:Float
Indicates the rotation of the DisplayObject instance, in degrees, from its
original orientation. Values from 0 to 180 represent clockwise rotation;
values from 0 to -180 represent counterclockwise rotation. Values outside
this range are added to or subtracted from 360 to obtain a value within
the range. For example, the statement my_video.rotation = 450
is the same as my_video.rotation = 90
.
The current scaling grid that is in effect. If set to 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:
- The upper-left corner outside of the rectangle
- The area above the rectangle
- The upper-right corner outside of the rectangle
- The area to the left of the rectangle
- The area to the right of the rectangle
- The lower-left corner outside of the rectangle
- The area below the rectangle
- The lower-right corner outside of the rectangle
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:
- Content in the center region is scaled normally.
- Content in the corners is not scaled.
- Content in the top and bottom regions is scaled horizontally only. Content in the left and right regions is scaled vertically only.
- All fills(including bitmaps, video, and gradients) are stretched to fit their shapes.
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.
Throws:
ArgumentError | If you pass an invalid argument to the method. |
---|
read onlywrite onlyscaleX:Float
Indicates the horizontal scale(percentage) of the object as applied from the registration point. The default registration point is(0,0). 1.0 equals 100% scale.
Scaling the local coordinate system changes the x
and
y
property values, which are defined in whole pixels.
read onlywrite onlyscaleY:Float
Indicates the vertical scale(percentage) of an object as applied from the registration point of the object. The default registration point is(0,0). 1.0 is 100% scale.
Scaling the local coordinate system changes the x
and
y
property values, which are defined in whole pixels.
read onlywrite onlyscrollRect:Rectangle
The scroll rectangle bounds of the display object. The display object is
cropped to the size defined by the rectangle, and it scrolls within the
rectangle when you change the 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.
The Stage of the display object. A Flash runtime application has only one
Stage object. For example, you can create and load multiple display
objects into the display list, and the 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
.
read onlywrite onlytransform:Transform
An object with properties pertaining to a display object's matrix, color
transform, and pixel bounds. The specific properties - matrix,
colorTransform, and three read-only properties
(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.
read onlywrite onlyvisible:Bool
Whether or not the display object is visible. Display objects that are not
visible are disabled. For example, if visible=false
for an
InteractiveObject instance, it cannot be clicked.
read onlywrite onlywidth:Float
Indicates the width of the display object, in pixels. The width is
calculated based on the bounds of the content of the display object. When
you set the 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.
Indicates the x coordinate of the DisplayObject instance relative to the local coordinates of the parent DisplayObjectContainer. If the object is inside a DisplayObjectContainer that has transformations, it is in the local coordinate system of the enclosing DisplayObjectContainer. Thus, for a DisplayObjectContainer rotated 90° counterclockwise, the DisplayObjectContainer's children inherit a coordinate system that is rotated 90° counterclockwise. The object's coordinates refer to the registration point position.
Indicates the y coordinate of the DisplayObject instance relative to the local coordinates of the parent DisplayObjectContainer. If the object is inside a DisplayObjectContainer that has transformations, it is in the local coordinate system of the enclosing DisplayObjectContainer. Thus, for a DisplayObjectContainer rotated 90° counterclockwise, the DisplayObjectContainer's children inherit a coordinate system that is rotated 90° counterclockwise. The object's coordinates refer to the registration point position.
Methods
getBounds (targetCoordinateSpace:DisplayObject):Rectangle
Returns a rectangle that defines the area of the display object relative
to the coordinate system of the 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.
Parameters:
targetCoordinateSpace | The display object that defines the coordinate system to use. |
---|
Returns:
The rectangle that defines the area of the display object relative
to the targetCoordinateSpace
object's coordinate
system.
getRect (targetCoordinateSpace:DisplayObject):Rectangle
Returns a rectangle that defines the boundary of the display object, based
on the coordinate system defined by the 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.
Parameters:
targetCoordinateSpace | The display object that defines the coordinate system to use. |
---|
Returns:
The rectangle that defines the area of the display object relative
to the targetCoordinateSpace
object's coordinate
system.
globalToLocal (pos:Point):Point
Converts the 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.
Parameters:
point | An object created with the Point class. The Point object specifies the x and y coordinates as properties. |
---|
Returns:
A Point object with coordinates relative to the display object.
hitTestObject (obj:DisplayObject):Bool
Evaluates the bounding box of the display object to see if it overlaps or
intersects with the bounding box of the obj
display object.
Parameters:
obj | The display object to test against. |
---|
Returns:
true
if the bounding boxes of the display objects
intersect; false
if not.
hitTestPoint (x:Float, y:Float, shapeFlag:Bool = false):Bool
Evaluates the display object to see if it overlaps or intersects with the
point specified by the 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).
Parameters:
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
( |
Returns:
true
if the display object overlaps or intersects
with the specified point; false
otherwise.
localToGlobal (point:Point):Point
Converts the 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.
Parameters:
point | The name or identifier of a point created with the Point class, specifying the x and y coordinates as properties. |
---|
Returns:
A Point object with coordinates relative to the Stage.