spark.core.IViewport - Adobe® Flex® 4 Language Reference (Flex 4)

Package	spark.core
Interface	public interface IViewport extends IVisualElement , ILayoutElement , ILayoutDirectionElement , IEventDispatcher
Implementors	GroupBase, RichEditableText

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The IViewport interface is implemented by components that support a viewport. If a component's children are larger than the component, and you want to clip the children to the component boundaries, you can define a viewport and scroll bars. A viewport is a rectangular subset of the area of a component that you want to display, rather than displaying the entire component.

A viewport on its own is not movable by the application user. However, you can combine a viewport with scroll bars so the user can scroll the viewport to see the entire content of the component. Use the Scroller component to add scrolbars to the component.

View the examples

See also

spark.components.Scroller

Public Properties

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	Property		Defined By
		alpha : Number Indicates the alpha transparency value of the object specified.	IVisualElement
		baseline : Object The vertical distance in pixels from the anchor target to the control's baseline position.	ILayoutElement
		baselinePosition : Number [read-only] The y-coordinate of the baseline of the first line of text of the component.	ILayoutElement
		bottom : Object The vertical distance in pixels from the bottom edge of the component to the anchor target's bottom edge.	ILayoutElement
		clipAndEnableScrolling : Boolean If true, specifies to clip the children to the boundaries of the viewport.	IViewport
		contentHeight : Number [read-only] The height of the viewport's content.	IViewport
		contentWidth : Number [read-only] The width of the viewport's contents.	IViewport
		depth : Number Determines the order in which items inside of containers are rendered.	IVisualElement
		designLayer : DesignLayer Specifies the optional DesignLayer instance associated with this visual element.	IVisualElement
		hasLayoutMatrix3D : Boolean [read-only] Contians true if the element has 3D Matrix.	ILayoutElement
		height : Number Indicates the height of the display object, in pixels.	IVisualElement
		horizontalCenter : Object The horizontal distance in pixels from the center of the component to the center of the anchor target's content area.	ILayoutElement
		horizontalScrollPosition : Number The x coordinate of the origin of the viewport in the component's coordinate system, where the default value is (0,0) corresponding to the upper-left corner of the component.	IViewport
		includeInLayout : Boolean Specifies whether this component is included in the layout of the parent container.	ILayoutElement
		is3D : Boolean [read-only] Contains true when the element is in 3D.	IVisualElement
		layoutDirection : String Specifies the desired layout direction for an element: one of LayoutDirection.LTR (left to right), LayoutDirection.RTL (right to left), or null (inherit).	ILayoutDirectionElement
		left : Object The horizontal distance in pixels from the left edge of the component to the anchor target's left edge.	ILayoutElement
		owner : DisplayObjectContainer The owner of this IVisualElement object.	IVisualElement
		parent : DisplayObjectContainer [read-only] The parent container or component for this component.	IVisualElement
		percentHeight : Number Number that specifies the height of a component as a percentage of its parent's size.	ILayoutElement
		percentWidth : Number Number that specifies the width of a component as a percentage of its parent's size.	ILayoutElement
		postLayoutTransformOffsets : mx.geom:TransformOffsets Defines a set of adjustments that can be applied to the object's transform in a way that is invisible to its parent's layout.	IVisualElement
		right : Object The horizontal distance in pixels from the right edge of the component to the anchor target's right edge.	ILayoutElement
		top : Object The vertical distance in pixels from the top edge of the component to the anchor target's top edge.	ILayoutElement
		verticalCenter : Object The vertical distance in pixels from the center of the component to the center of the anchor target's content area.	ILayoutElement
		verticalScrollPosition : Number The y coordinate of the origin of the viewport in the component's coordinate system, where the default value is (0,0) corresponding to the upper-left corner of the component.	IViewport
		visible : Boolean Controls the visibility of this visual element.	IVisualElement
		width : Number Indicates the width of the display object, in pixels.	IVisualElement
		x : Number Indicates the x coordinate of the DisplayObject instance relative to the local coordinates of the parent DisplayObjectContainer.	IVisualElement
		y : Number Indicates the y coordinate of the DisplayObject instance relative to the local coordinates of the parent DisplayObjectContainer.	IVisualElement

Public Methods

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	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.	IEventDispatcher
		dispatchEvent(event:Event):Boolean Dispatches an event into the event flow.	IEventDispatcher
		getBoundsXAtSize(width:Number, height:Number, postLayoutTransform:Boolean = true):Number Returns the x coordinate of the element's bounds at the specified element size.	ILayoutElement
		getBoundsYAtSize(width:Number, height:Number, postLayoutTransform:Boolean = true):Number Returns the y coordinate of the element's bounds at the specified element size.	ILayoutElement
		getHorizontalScrollPositionDelta(navigationUnit:uint):Number Returns the amount to add to the viewport's current horizontalScrollPosition to scroll by the requested scrolling unit.	IViewport
		getLayoutBoundsHeight(postLayoutTransform:Boolean = true):Number Returns the element's layout height.	ILayoutElement
		getLayoutBoundsWidth(postLayoutTransform:Boolean = true):Number Returns the element's layout width.	ILayoutElement
		getLayoutBoundsX(postLayoutTransform:Boolean = true):Number Returns the x coordinate that the element uses to draw on screen.	ILayoutElement
		getLayoutBoundsY(postLayoutTransform:Boolean = true):Number Returns the y coordinate that the element uses to draw on screen.	ILayoutElement
		getLayoutMatrix():Matrix Returns the transform matrix that is used to calculate the component's layout relative to its siblings.	ILayoutElement
		getLayoutMatrix3D():Matrix3D Returns the layout transform Matrix3D for this element.	ILayoutElement
		getMaxBoundsHeight(postLayoutTransform:Boolean = true):Number Returns the element's maximum height.	ILayoutElement
		getMaxBoundsWidth(postLayoutTransform:Boolean = true):Number Returns the element's maximum width.	ILayoutElement
		getMinBoundsHeight(postLayoutTransform:Boolean = true):Number Returns the element's minimum height.	ILayoutElement
		getMinBoundsWidth(postLayoutTransform:Boolean = true):Number Returns the element's minimum width.	ILayoutElement
		getPreferredBoundsHeight(postLayoutTransform:Boolean = true):Number Returns the element's preferred height.	ILayoutElement
		getPreferredBoundsWidth(postLayoutTransform:Boolean = true):Number Returns the element's preferred width.	ILayoutElement
		getVerticalScrollPositionDelta(navigationUnit:uint):Number Returns the amount to add to the viewport's current verticalScrollPosition to scroll by the requested scrolling unit.	IViewport
		hasEventListener(type:String):Boolean Checks whether the EventDispatcher object has any listeners registered for a specific type of event.	IEventDispatcher
		invalidateLayoutDirection():void An element must call this method when its layoutDirection changes or when its parent's layoutDirection changes.	ILayoutDirectionElement
		removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes a listener from the EventDispatcher object.	IEventDispatcher
		setLayoutBoundsPosition(x:Number, y:Number, postLayoutTransform:Boolean = true):void Sets the coordinates that the element uses to draw on screen.	ILayoutElement
		setLayoutBoundsSize(width:Number, height:Number, postLayoutTransform:Boolean = true):void Sets the layout size of the element.	ILayoutElement
		setLayoutMatrix(value:Matrix, invalidateLayout:Boolean):void Sets the transform Matrix that is used to calculate the component's layout size and position relative to its siblings.	ILayoutElement
		setLayoutMatrix3D(value:Matrix3D, invalidateLayout:Boolean):void Sets the transform Matrix3D that is used to calculate the component's layout size and position relative to its siblings.	ILayoutElement
		transformAround(transformCenter:Vector3D, scale:Vector3D = null, rotation:Vector3D = null, translation:Vector3D = null, postLayoutScale:Vector3D = null, postLayoutRotation:Vector3D = null, postLayoutTranslation:Vector3D = null, invalidateLayout:Boolean = true):void A utility method to update the rotation, scale, and translation of the transform while keeping a particular point, specified in the component's own coordinate space, fixed in the parent's coordinate space.	ILayoutElement
		willTrigger(type:String):Boolean Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.	IEventDispatcher

Property Detail

clipAndEnableScrolling

property

clipAndEnableScrolling:Boolean

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

If true, specifies to clip the children to the boundaries of the viewport. If false, the container children extend past the container boundaries, regardless of the size specification of the component.

The default value is false.

Implementation
public function get clipAndEnableScrolling():Boolean
public function set clipAndEnableScrolling(value:Boolean):void

contentHeight

property

contentHeight:Number [read-only]

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The height of the viewport's content. If clipAndEnabledScrolling is true, the viewport's contentHeight defines the limit for vertical scrolling and the viewport's actual height defines how much of the content is visible. To scroll through the content vertically, vary the verticalScrollPosition between 0 and contentHeight - height.

Implementations of this property must be Bindable and must generate events of type propertyChange.

Implementation
public function get contentHeight():Number

contentWidth

property

contentWidth:Number [read-only]

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The width of the viewport's contents. If clipAndEnabledScrolling is true, the viewport's contentWidth defines the limit for horizontal scrolling and the viewport's actual width defines how much of the content is visible. To scroll through the content horizontally, vary the horizontalScrollPosition between 0 and contentWidth - width.

Implementations of this property must be Bindable and must generate events of type propertyChange.

Implementation
public function get contentWidth():Number

horizontalScrollPosition

property

horizontalScrollPosition:Number

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The x coordinate of the origin of the viewport in the component's coordinate system, where the default value is (0,0) corresponding to the upper-left corner of the component. If clipAndEnableScrolling is true, setting this property typically causes the viewport to be set to:

      new Rectangle(horizontalScrollPosition, verticalScrollPosition, width, height)

Implementations of this property must be Bindable and must generate events of type propertyChange.

The default value is 0.

Implementation
public function get horizontalScrollPosition():Number
public function set horizontalScrollPosition(value:Number):void

See also

target
verticalScrollPosition

verticalScrollPosition

property

verticalScrollPosition:Number

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

The y coordinate of the origin of the viewport in the component's coordinate system, where the default value is (0,0) corresponding to the upper-left corner of the component. If clipAndEnableScrolling is true, setting this property typically causes the viewport to be set to:

      new Rectangle(horizontalScrollPosition, verticalScrollPosition, width, height)

Implementations of this property must be Bindable and must generate events of type propertyChange.

The default value is 0.

Implementation
public function get verticalScrollPosition():Number
public function set verticalScrollPosition(value:Number):void

See also

horizontalScrollPosition

Method Detail

getHorizontalScrollPositionDelta

()

method

public function getHorizontalScrollPositionDelta(navigationUnit:uint):Number

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

Returns the amount to add to the viewport's current horizontalScrollPosition to scroll by the requested scrolling unit.

Parameters

navigationUnit:uint — The amount to scroll. The value must be one of the following spark.core.NavigationUnit constants:

LEFT
RIGHT
PAGE_LEFT
PAGE_RIGHT
HOME
END

To scroll by a single column, use LEFT or RIGHT. To scroll to the first or last column, use HOME or END.

Returns

Number — The number of pixels to add to horizontalScrollPosition.

See also

spark.core.NavigationUnit

getVerticalScrollPositionDelta

()

method

public function getVerticalScrollPositionDelta(navigationUnit:uint):Number

Language Version:

ActionScript 3.0

Product Version:

Flex 4

Runtime Versions:

Flash Player 10, AIR 1.5

Returns the amount to add to the viewport's current verticalScrollPosition to scroll by the requested scrolling unit.

Parameters

navigationUnit:uint — The amount to scroll. The value of unit must be one of the following spark.core.NavigationUnit constants:

UP
DOWN
PAGE_UP
PAGE_DOWN
HOME
END

To scroll by a single row use UP or DOWN. To scroll to the first or last row, use HOME or END.

Returns

Number — The number of pixels to add to verticalScrollPosition.

See also

spark.core.NavigationUnit

Examples How to use this example

IViewportExample.mxml

<?xml version="1.0" encoding="utf-8"?>
<!-- Simple example to demonstrate Spark IViewport interface -->
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
    xmlns:mx="library://ns.adobe.com/flex/mx" 
    xmlns:s="library://ns.adobe.com/flex/spark" >
    <s:layout>
        <s:HorizontalLayout/>
    </s:layout>
    
    <s:Panel title="IViewport Component Example"
        width="75%" height="75%" 
        horizontalCenter="0" verticalCenter="0"> 

        <s:Label text="The Group container implements IViewport. Therefore, you can clip its contents and use it with scrollbars."
            color="blue"
            top="10"/>
        <s:Group id="myGroup" width="100" height="100"
            clipAndEnableScrolling="true"
            horizontalScrollPosition="50" verticalScrollPosition="50" 
            left="100" top="40"> 
            <mx:Image width="300" height="400" 
                source="@Embed(source='/assets/logo.jpg')"/>
        </s:Group>
        <s:VScrollBar viewport="{myGroup}" height="100" left="210" top="40"/>
        <s:HScrollBar viewport="{myGroup}" width="100" left="100" top="150"/>

    </s:Panel>
</s:Application>