Package | mx.containers |
Class | public class Canvas |
Inheritance | Canvas Container UIComponent FlexSprite Sprite DisplayObjectContainer InteractiveObject DisplayObject EventDispatcher Object |
Implements | IConstraintLayout |
Subclasses | AttachmentHeaderBase, HelpClose, PanelContent, ProgressSectionBarNav, RendererBase, ResourceContainer, SearchSelectorBase, StartProcessBase, ToDoBase, Tracking, Workspace |
Language Version: | ActionScript 3.0 |
Product Version: | Flex 3 |
Runtime Versions: | Flash Player 9, AIR 1.1 |
Starting with Flex 4.0, Adobe recommends that you use the spark.components.BorderContainer class as an alternative to this class. | |
Starting with Flex 4.0, Adobe recommends that you use the spark.components.Group class as an alternative to this class. |
A Halo Canvas layout container defines a rectangular region in which you place child containers and controls. It is the only container that lets you explicitly specify the location of its children within the container by using the
x
and
y
properties of each child.
Note: Adobe recommends that, when possible, you use the Spark containers with BasicLayout instead of the Halo Canvas container.
Flex sets the children of a Canvas layout container to their
preferred width and preferred height.
You may override the value for a child's
preferred width by setting its width
property to either
a fixed pixel value or a percentage of the container size.
You can set the preferred height in a similar manner.
If you use percentage sizing inside a Canvas container, some of your components may overlap. If this is not the effect you want, plan your component positions and sizes carefully.
The Canvas container has the following default sizing characteristics:
Characteristic | Description |
---|---|
Default size | Large enough to hold all its children at the default sizes of the children |
Default padding | 0 pixels for the top, bottom, left, and right values |
The <mx:Canvas>
tag inherits all the tag attributes
of its superclass. Use the following syntax:
<mx:Canvas> ... child tags ... </mx:Canvas>
More examples
Related API Elements
Property | Defined By | ||
---|---|---|---|
accessibilityImplementation : AccessibilityImplementation
The current accessibility implementation (AccessibilityImplementation)
for this InteractiveObject instance. | InteractiveObject | ||
accessibilityProperties : AccessibilityProperties
The current accessibility options for this display object. | DisplayObject | ||
alpha : Number
Indicates the alpha transparency value of the object specified. | DisplayObject | ||
blendMode : String
A value from the BlendMode class that specifies which blend mode to use. | DisplayObject | ||
blendShader : Shader [write-only]
Sets a shader that is used for blending the foreground and background. | DisplayObject | ||
buttonMode : Boolean
Specifies the button mode of this sprite. | Sprite | ||
cacheAsBitmap : Boolean
If set to true, Flash runtimes cache an internal bitmap representation of the
display object. | DisplayObject | ||
cacheAsBitmapMatrix : Matrix
If non-null, this Matrix object defines how a display object is rendered when
cacheAsBitmap is set to true. | DisplayObject | ||
constructor : Object
A reference to the class object or constructor function for a given object instance. | Object | ||
contextMenu : NativeMenu
Specifies the context menu associated with this object. | InteractiveObject | ||
dropTarget : DisplayObject [read-only]
Specifies the display object over which the sprite is being dragged, or on
which the sprite was dropped. | Sprite | ||
filters : Array
An indexed array that contains each filter object currently associated with the display object. | DisplayObject | ||
focusRect : Object
Specifies whether this object displays a focus rectangle. | InteractiveObject | ||
graphics : Graphics [read-only]
Specifies the Graphics object that belongs to this sprite where vector
drawing commands can occur. | Sprite | ||
hitArea : Sprite
Designates another sprite to serve as the hit area for a sprite. | Sprite | ||
loaderInfo : LoaderInfo [read-only]
Returns a LoaderInfo object containing information about loading the file
to which this display object belongs. | DisplayObject | ||
mask : DisplayObject
The calling display object is masked by the specified mask object. | DisplayObject | ||
metaData : Object
Obtains the meta data object of the DisplayObject instance if meta data was stored alongside the
the instance of this DisplayObject in the SWF file through a PlaceObject4 tag. | DisplayObject | ||
mouseChildren : Boolean
Determines whether or not the children of the object are mouse, or user input device, enabled. | DisplayObjectContainer | ||
mouseEnabled : Boolean
Specifies whether this object receives mouse, or other user input, messages. | InteractiveObject | ||
mouseX : Number [read-only]
Indicates the x coordinate of the mouse or user input device position, in pixels. | DisplayObject | ||
mouseY : Number [read-only]
Indicates the y coordinate of the mouse or user input device position, in pixels. | DisplayObject | ||
name : String
Indicates the instance name of the DisplayObject. | DisplayObject | ||
needsSoftKeyboard : Boolean
Specifies whether a virtual keyboard (an on-screen, software keyboard) should display
when this InteractiveObject instance receives focus. | InteractiveObject | ||
opaqueBackground : Object
Specifies whether the display object is opaque with a certain background color. | DisplayObject | ||
root : DisplayObject [read-only]
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. | DisplayObject | ||
scale9Grid : Rectangle
The current scaling grid that is in effect. | DisplayObject | ||
scrollRect : Rectangle
The scroll rectangle bounds of the display object. | DisplayObject | ||
softKeyboard : String
Controls the appearance of the soft keyboard. | InteractiveObject | ||
softKeyboardInputAreaOfInterest : Rectangle
Defines the area that should remain on-screen when a soft keyboard is displayed (not available on iOS). | InteractiveObject | ||
soundTransform : flash.media:SoundTransform
Controls sound within this sprite. | Sprite | ||
stage : Stage [read-only]
The Stage of the display object. | DisplayObject | ||
tabChildren : Boolean
Determines whether the children of the object are tab enabled. | DisplayObjectContainer | ||
tabEnabled : Boolean
Specifies whether this object is in the tab order. | InteractiveObject | ||
tabIndex : int
Specifies the tab ordering of objects in a SWF file. | InteractiveObject | ||
textSnapshot : flash.text:TextSnapshot [read-only]
Returns a TextSnapshot object for this DisplayObjectContainer instance. | DisplayObjectContainer | ||
useHandCursor : Boolean
A Boolean value that indicates whether the pointing hand (hand cursor) appears when the pointer rolls
over a sprite in which the buttonMode property is set to true. | Sprite |
Method | Defined By | ||
---|---|---|---|
addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void
Registers an event listener object with an EventDispatcher object so that the listener
receives notification of an event. | EventDispatcher | ||
Indicates whether the security restrictions
would cause any display objects to be omitted from the list returned by calling
the DisplayObjectContainer.getObjectsUnderPoint() method
with the specified point point. | DisplayObjectContainer | ||
Determines whether the specified display object is a child of the DisplayObjectContainer instance or
the instance itself. | DisplayObjectContainer | ||
Returns a rectangle that defines the area of the display object relative to the coordinate system
of the targetCoordinateSpace object. | DisplayObject | ||
Returns an array of objects that lie under the specified point and are children
(or grandchildren, and so on) of this DisplayObjectContainer instance. | DisplayObjectContainer | ||
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. | DisplayObject | ||
Converts the point object from the Stage (global) coordinates
to the display object's (local) coordinates. | DisplayObject | ||
Converts a two-dimensional point from the Stage (global) coordinates to a
three-dimensional display object's (local) coordinates. | DisplayObject | ||
Checks whether the EventDispatcher object has any listeners registered for a specific type
of event. | EventDispatcher | ||
Indicates whether an object has a specified property defined. | Object | ||
Evaluates the bounding box of the display object to see if it overlaps or intersects with the
bounding box of the obj display object. | DisplayObject | ||
Evaluates the display object to see if it overlaps or intersects with the
point specified by the x and y parameters. | DisplayObject | ||
Indicates whether an instance of the Object class is in the prototype chain of the object specified
as the parameter. | Object | ||
Converts a three-dimensional point of the three-dimensional display
object's (local) coordinates to a two-dimensional point in the Stage (global) coordinates. | DisplayObject | ||
Converts the point object from the display object's (local) coordinates to the
Stage (global) coordinates. | DisplayObject | ||
Indicates whether the specified property exists and is enumerable. | Object | ||
Removes all child DisplayObject instances from the child list of the DisplayObjectContainer instance. | DisplayObjectContainer | ||
Removes a listener from the EventDispatcher object. | EventDispatcher | ||
Raises a virtual keyboard. | InteractiveObject | ||
Sets the availability of a dynamic property for loop operations. | Object | ||
Lets the user drag the specified sprite. | Sprite | ||
Lets the user drag the specified sprite on a touch-enabled device. | Sprite | ||
Recursively stops the timeline execution of all MovieClips rooted at this object. | DisplayObjectContainer | ||
Ends the startDrag() method. | Sprite | ||
Ends the startTouchDrag() method, for use with touch-enabled devices. | Sprite | ||
Swaps the z-order (front-to-back order) of the two specified child objects. | DisplayObjectContainer | ||
Swaps the z-order (front-to-back order) of the child objects at the two specified index positions in the
child list. | DisplayObjectContainer | ||
Returns the string representation of this object, formatted according to locale-specific conventions. | Object | ||
Returns the primitive value of the specified object. | Object | ||
Checks whether an event listener is registered with this EventDispatcher object or any of
its ancestors for the specified event type. | EventDispatcher |
Method | Defined By |
---|
Styles are either common or associated with a specific theme. If the style is common, it can be used with any theme. If a style is associated with a specific theme, it can only be used if your application uses that theme.
<?xml version="1.0"?> <!-- Simple example to demonstrate the Halo Canvas layout container. --> <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx"> <s:Panel title="Canvas Container Example" width="75%" height="75%" horizontalCenter="0" verticalCenter="0"> <s:VGroup left="10" right="10" top="10" bottom="10"> <s:Label width="100%" color="blue" text="Use absolute positioning to place the children of a Canvas container." /> <mx:Canvas borderStyle="solid" height="200" width="100%"> <!-- Stagger the position of the TextInput controls using absolute positioning.--> <s:TextInput width="100" x="50" y="5"/> <s:TextInput width="100" x="100" y="30"/> <s:TextInput width="100" x="150" y="55"/> <!-- Overlap the VBox containers using layout constraints.--> <mx:VBox right="115" bottom="50" width="75" height="75" backgroundColor="#0080C0" /> <mx:VBox right="70" bottom="30" width="75" height="75" backgroundColor="#FFFF80" /> <mx:VBox right="25" bottom="10" width="75" height="75" backgroundColor="#8080C0" alpha="0.8" /> <s:RichEditableText right="25" y="110" text="The Canvas container lets you place components on top of each other." editable="false" /> </mx:Canvas> </s:VGroup> </s:Panel> </s:Application>
Wed Nov 21 2018, 06:34 AM -08:00