flashx.textLayout.compose.IFlowComposer - Adobe® Flex® 4 Language Reference (Flex 4)

Package	flashx.textLayout.compose
Interface	public interface IFlowComposer
Implementors	StandardFlowComposer

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

IFlowComposer defines the interface for managing the layout and display of a text flow.

Text flows displayed with a flow composer implementation can be dynamic and interactive. A flow composer manages one or more display controller. Each controller is associated with a display object container (such as a Sprite) through which the lines created for the text flow are ultimately displayed. The following diagram illustrates the relationship between TextFlow, IFlowComposer, ContainerController, and DisplayObjectContainer objects:

IFlowComposer

A flow composer calculates which portion of a text flow fits in each container and adds the appropriate text lines to the container's display object. The IFlowComposer interface defines separate methods for layout calculations and for updating the display. IFlowComposer also defines methods for incrementally composing and updating a text flow. These methods can be used to avoid blocking the user interface when updating long text flows.

In addition to managing text composition and display, a flow composer controls which container has focus, manages the display of the selection highlight (which can cross container boundaries), and provides direct access to all the TextLine objects in the flow.

To use an IFlowComposer implementation, assign an instance of that implementation to the flowComposer property of a TextFlow object. Call the updateAllControllers() method to lay out and display the text in the containers attached to the flow composer.

Note: For simple, static text flows, you can also use the one of the text line factory classes. These factory classes will typically create lines with less overhead than a flow composer, but do not support editing, dynamic changes, or user interaction.

Public Properties

	Property		Defined By
		composing : Boolean [read-only] True, if the flow composer is currently performing a composition operation.	IFlowComposer
		damageAbsoluteStart : int [read-only] The first invalid position in the root element, as an absolute position from the start of the flow.	IFlowComposer
		numControllers : int [read-only] The number of containers assigned to this IFlowComposer instance.	IFlowComposer
		numLines : int [read-only] The total number of lines in the flow.	IFlowComposer
		rootElement : ContainerFormattedElement [read-only] The root element associated with this IFlowComposer instance.	IFlowComposer
		swfContext : ISWFContext The ISWFContext instance to be used for calls that must be made in a specific SWF context Implementations of IFlowComposer should allow this property to be set so that users of the interface can create lines in a different SWF context than the one containing the implementation.	IFlowComposer

Public Methods

	Method		Defined By
		addController(controller:ContainerController):void Adds a controller to this IFlowComposer instance.	IFlowComposer
		addControllerAt(controller:ContainerController, index:int):void Adds a controller to this IFlowComposer instance at the specified index.	IFlowComposer
		compose():Boolean Calculates how many lines are necessary to display the content in the root element of the flow and the positions of these lines in the flow's display containers.	IFlowComposer
		composeToController(index:int):Boolean Composes the content of the root element up to and including the container at the specified index.	IFlowComposer
		composeToPosition(absolutePosition:int):Boolean Composes the content of the root element up to the specified position.	IFlowComposer
		damage(startPosition:int, damageLength:int, damageType:String):void Mark lines as damaged and needing a recompose.	IFlowComposer
		findControllerIndexAtPosition(absolutePosition:int, preferPrevious:Boolean = false):int Returns the index of the controller containing the content at the specified position.	IFlowComposer
		findLineAtPosition(absolutePosition:int, preferPrevious:Boolean = false):flashx.textLayout.compose:TextFlowLine Returns the TextFlowLine object containing the content at the specified position.	IFlowComposer
		findLineIndexAtPosition(absolutePosition:int, preferPrevious:Boolean = false):int Returns the sequential line number of the TextFlowLine object that contains the content at the specified position.	IFlowComposer
		getControllerAt(index:int):ContainerController Returns the ContainerController object at the specified index.	IFlowComposer
		getControllerIndex(controller:ContainerController):int Returns the index of the specified ContainerController object.	IFlowComposer
		getLineAt(index:int):flashx.textLayout.compose:TextFlowLine Returns the line with the specified line number.	IFlowComposer
		interactionManagerChanged(newInteractionManager:ISelectionManager):void Called by the TextFlow when the interaction manager changes.	IFlowComposer
		isDamaged(absolutePosition:int):Boolean Indicates whether any TextFlowLine objects between the beginning of the flow and the line containing the content at the specified position are marked as damaged.	IFlowComposer
		removeAllControllers():void Removes all controllers from this IFlowComposer instance.	IFlowComposer
		removeController(controller:ContainerController):void Removes a controller from this IFlowComposer instance.	IFlowComposer
		removeControllerAt(index:int):void Removes the controller at the specified index from this IFlowComposer instance.	IFlowComposer
		setFocus(absolutePosition:int, preferPrevious:Boolean = false):void Sets the focus to the container that contains the location specified by the absolutePosition parameter.	IFlowComposer
		setRootElement(newRootElement:ContainerFormattedElement):void	IFlowComposer
		updateAllControllers():Boolean Composes the content of the root element and updates the display.	IFlowComposer
		updateLengths(startPosition:int, deltaLength:int):void Update the lengths in the lines to maintain mapping to the TextFlow.	IFlowComposer
		updateToController(index:int):Boolean Composes and updates the display up to and including the container at the specified index.	IFlowComposer

Property Detail

composing

property

composing:Boolean [read-only]

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

True, if the flow composer is currently performing a composition operation.

Implementation
public function get composing():Boolean

damageAbsoluteStart

property

damageAbsoluteStart:int [read-only]

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

The first invalid position in the root element, as an absolute position from the start of the flow.

Implementation
public function get damageAbsoluteStart():int

numControllers

property

numControllers:int [read-only]

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

The number of containers assigned to this IFlowComposer instance.

Implementation
public function get numControllers():int

numLines

property

numLines:int [read-only]

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

The total number of lines in the flow.

Implementation
public function get numLines():int

rootElement

property

rootElement:ContainerFormattedElement [read-only]

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

The root element associated with this IFlowComposer instance.

Only a TextFlow object can be a root element.

Implementation
public function get rootElement():ContainerFormattedElement

See also

ContainerFormattedElement

swfContext

property

swfContext:ISWFContext

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

The ISWFContext instance to be used for calls that must be made in a specific SWF context

Implementations of IFlowComposer should allow this property to be set so that users of the interface can create lines in a different SWF context than the one containing the implementation. A default implementation of ISWFContext should also be supplied.

Implementation
public function get swfContext():ISWFContext
public function set swfContext(value:ISWFContext):void

See also

ISWFContext

Method Detail

addController

()

method

public function addController(controller:ContainerController):void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Adds a controller to this IFlowComposer instance.

The container is added to the end of the container list.

Parameters

controller:ContainerController — The ContainerController object to add.

addControllerAt

()

method

public function addControllerAt(controller:ContainerController, index:int):void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Adds a controller to this IFlowComposer instance at the specified index.

The list of controllers is 0-based (the first controller has an index of 0).

Parameters

	`controller:ContainerController` — The ContainerController object to add.

	`index:int` — A numeric index that specifies the position in the controller list at which to insert the ContainerController object.

compose

()

method

public function compose():Boolean

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Calculates how many lines are necessary to display the content in the root element of the flow and the positions of these lines in the flow's display containers.

Implementations of this method should not update the display, but should save the results so that subsequent calls to compose() or updateAllControllers() do not perform an additional recomposition if the flow content has not changed.

If the contents of any container have changed, the method must return true.

Returns

Boolean — true if anything changed.

composeToController

()

method

public function composeToController(index:int):Boolean

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Composes the content of the root element up to and including the container at the specified index.

If the contents of any container up to and including the container at the specified index has changed, the method returns true. If index is greater than the number of controllers (or not specified), then all containers are composed.

Parameters

index:int (default = NaN) — compose at least up to this container in the TextFlow. If controllerIndex is greater than the number of controllers, compose to the end of the last container.

Returns

Boolean — true if anything changed.

composeToPosition

()

method

public function composeToPosition(absolutePosition:int):Boolean

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Composes the content of the root element up to the specified position.

If the contents of any container up to and including the container holding the content at the specified position has changed, the method returns true. If absolutePosition is greater than the length of the TextFlow (or not specified), then the entire flow is composed.

Parameters

absolutePosition:int (default = NaN) — compose at least up to this position in the TextFlow. By default or if absolutePosition is past the end of the flow compose to the end of the flow.

Returns

Boolean — true if anything changed.

damage

()

method

public function damage(startPosition:int, damageLength:int, damageType:String):void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Mark lines as damaged and needing a recompose.

Parameters

	`startPosition:int` — beginning of range to damage

	`damageLength:int` — number of characters to damage

	`damageType:String` — type of damage. One of flashx.textLayout.compose.FlowDamageType

findControllerIndexAtPosition

()

method

public function findControllerIndexAtPosition(absolutePosition:int, preferPrevious:Boolean = false):int

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Returns the index of the controller containing the content at the specified position.

A position can be considered to be the division between two characters or other elements of a text flow. If the value in absolutePosition is a position between the last character of one container and the first character of the next, then the preceding container is returned if the preferPrevious parameter is set to true and the later container is returned if the preferPrevious parameter is set to false.

The method must return -1 if the content at the specified position is not in any container or is outside the range of positions in the text flow.

Parameters

	`absolutePosition:int` — The position of the content for which the container index is sought.

	`preferPrevious:Boolean` (default = `false`) — Specifies which container index to return when the position is between the last element in one container and the first element in the next.

Returns

int — the index of the container controller or -1 if not found.

findLineAtPosition

()

method

 public function findLineAtPosition(absolutePosition:int, preferPrevious:Boolean = false):flashx.textLayout.compose:TextFlowLine

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Returns the TextFlowLine object containing the content at the specified position.

A position can be considered to be the division between two characters or other elements of a text flow. If the value in absolutePosition is a position between the last element of one line and the first element of the next, then the preceding line is returned if the preferPrevious parameter is set to true and the later line is returned if the preferPrevious parameter is set to false.

Parameters

	`absolutePosition:int` — The position of the content for which you want the TextFlowLine object.

	`preferPrevious:Boolean` (default = `false`) — Specifies which line to return when the position is between the last element of one line and the first element of the next.

Returns

flashx.textLayout.compose:TextFlowLine — the TextFlowLine containing the content at the specified position, or null if not found.

findLineIndexAtPosition

()

method

public function findLineIndexAtPosition(absolutePosition:int, preferPrevious:Boolean = false):int

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Returns the sequential line number of the TextFlowLine object that contains the content at the specified position.

The number of the first line is 0 and the number of the last line is equal to the number of lines minus one. If the position specified in absolutePosition is past the end of the text flow, this method must return the number that will be assigned to the next new line added to the text flow (which is equal to the number of current lines).

A position can be considered to be the division between two characters or other elements of a text flow. If the value in absolutePosition is a position between the last line of one container and the first line of the next, then the preceding container is returned if the preferPrevious parameter is set to true and the later container is returned if the preferPrevious parameter is set to false.

Parameters

	`absolutePosition:int` — The position of the content for which you want the text line.

	`preferPrevious:Boolean` (default = `false`) — Specifies which container index to return when the position is between the last line in one container and the first line in the next.

Returns

int — the index of the text line at the specified position. If not found, treats as past the end and returns the number of lines.

getControllerAt

()

method

public function getControllerAt(index:int):ContainerController

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Returns the ContainerController object at the specified index.

Parameters

index:int — The index of the ContainerController object to return.

Returns

ContainerController — the ContainerController object at the specified position.

getControllerIndex

()

method

public function getControllerIndex(controller:ContainerController):int

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Returns the index of the specified ContainerController object.

Parameters

controller:ContainerController — A reference to the ContainerController object to find.

Returns

int — the index of the specified ContainerController object or -1 if the controller is not attached to this flow composer.

getLineAt

()

method

public function getLineAt(index:int):flashx.textLayout.compose:TextFlowLine

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Returns the line with the specified line number.

The list of lines is numbered from zero to the number of lines minus one. If the value in index is outside the bounds of the list of lines, then this function returns null.

Parameters

index:int — The line number of the TextFlowLine object to return.

Returns

flashx.textLayout.compose:TextFlowLine — the TextFlowLine with the specified line number, or null, if not found.

interactionManagerChanged

()

method

public function interactionManagerChanged(newInteractionManager:ISelectionManager):void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Called by the TextFlow when the interaction manager changes.

Implementations of IFlowComposer should update event listeners and properties that reference the interaction manager.

Parameters

newInteractionManager:ISelectionManager — The new ISelectionManager instance.

isDamaged

()

method

public function isDamaged(absolutePosition:int):Boolean

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Indicates whether any TextFlowLine objects between the beginning of the flow and the line containing the content at the specified position are marked as damaged.

Parameters

absolutePosition:int — the last position in the area of interest

Returns

Boolean — true if any of the TextFlowLine objects from the start of the flow up to the line containing the content at absolutePosition are marked as damaged.

removeAllControllers

()

method

public function removeAllControllers():void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Removes all controllers from this IFlowComposer instance.

removeController

()

method

public function removeController(controller:ContainerController):void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Removes a controller from this IFlowComposer instance.

Parameters

controller:ContainerController — The ContainerController instance to remove.

removeControllerAt

()

method

public function removeControllerAt(index:int):void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Removes the controller at the specified index from this IFlowComposer instance.

Parameters

index:int — The index of the ContainerController object to remove.

setFocus

()

method

public function setFocus(absolutePosition:int, preferPrevious:Boolean = false):void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Sets the focus to the container that contains the location specified by the absolutePosition parameter.

It is the responsibility of the implementation to define what setting the focus means. For example, an implementation could use the built-in focus property of the Stage object (as long as the containers were InteractiveObjects) or the implementation could manage the focus some other way.

Parameters

	`absolutePosition:int` — Specifies the position in the text flow of the container to receive focus.

	`preferPrevious:Boolean` (default = `false`) — If true and the position is the before the first character in a container, sets focus to the end of the previous container.

See also

flash.display.Stage.focus

setRootElement

()

method

public function setRootElement(newRootElement:ContainerFormattedElement):void

Parameters

newRootElement:ContainerFormattedElement

updateAllControllers

()

method

public function updateAllControllers():Boolean

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Composes the content of the root element and updates the display.

Text layout is typically conducted in two phases: composition and display. In the composition phase, the flow composer calculates how many lines are necesary to display the content as well as the position of these lines in the flow's display containers. In the display phase, the flow composer updates the display object children of its containers. The updateAllControllers() method is expected to carry out both phases. An efficient implementation will keep track of changes to content so that a full cycle of composition and display is only performed when necessary.

This method updates all the text lines and the display list immediately and synchronously.

If the contents of any container is changed, the method must return true.

Returns

Boolean — true if anything changed.

updateLengths

()

method

public function updateLengths(startPosition:int, deltaLength:int):void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Update the lengths in the lines to maintain mapping to the TextFlow.

Parameters

	`startPosition:int` — beginning of change in length

	`deltaLength:int` — change in number of characters.

updateToController

()

method

public function updateToController(index:int):Boolean

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Composes and updates the display up to and including the container at the specified index.

The updateToController() method is expected to both compose the content and update the display so that all containers up to and including the container at the specified index are current. For example, if you have a chain of twenty containers and specify an index of 10, updateToController() must ensures that the first through the tenth (indexes 0-9) containers are composed and displayed. Composition can stop at that point. If controllerIndex is -1 (or not specified), then all containers should be updated.

This method updates all the text lines and the display list immediately and synchronously.

If the contents of any container is changed, the method must return true.

Parameters

index:int (default = NaN) — index of the last container to update, by default will update all containers

Returns

Boolean — true if anything changed.