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Class ScrollBar

A widget which implements a canonical scroll bar. The namespace for the ScrollBar class statics.

Hierarchy

Implements

  • IDisposable
  • IMessageHandler

Index

Modules

Interfaces

Type aliases

Constructors

Properties

Accessors

Methods

Type aliases

Static Orientation

Orientation: "horizontal" | "vertical"

A type alias for a scroll bar orientation.

Constructors

constructor

Properties

Private _maximum

_maximum: number = 100

Private _orientation

_orientation: Orientation

Private _page

_page: number = 10

Private _pageRequested

_pageRequested: Signal<this, "decrement" | "increment"> = new Signal<this, 'decrement' | 'increment'>(this)

Private _pressData

_pressData: IPressData | null = null

Private _repeatTimer

_repeatTimer: number = -1

Private _stepRequested

_stepRequested: Signal<this, "decrement" | "increment"> = new Signal<this, 'decrement' | 'increment'>(this)

Private _thumbMoved

_thumbMoved: Signal<this, number> = new Signal<this, number>(this)

Private _value

_value: number = 0

node

node: HTMLElement

Get the DOM node owned by the widget.

Accessors

dataset

  • get dataset(): DOMStringMap

decrementNode

  • get decrementNode(): HTMLDivElement

  • The scroll bar decrement button node.

    Notes

    Modifying this node directly can lead to undefined behavior.

    Returns HTMLDivElement

disposed

  • get disposed(): ISignal<this, void>

  • A signal emitted when the widget is disposed.

    Returns ISignal<this, void>

id

  • get id(): string
  • set id(value: string): void

  • Get the id of the widget's DOM node.

    Returns string

  • Set the id of the widget's DOM node.

    Parameters

    • value: string

    Returns void

incrementNode

  • get incrementNode(): HTMLDivElement

  • The scroll bar increment button node.

    Notes

    Modifying this node directly can lead to undefined behavior.

    Returns HTMLDivElement

isAttached

  • get isAttached(): boolean

isDisposed

  • get isDisposed(): boolean

isHidden

  • get isHidden(): boolean

isVisible

  • get isVisible(): boolean

  • Test whether the widget is visible.

    Notes

    A widget is visible when it is attached to the DOM, is not explicitly hidden, and has no explicitly hidden ancestors.

    Returns boolean

layout

  • get layout(): Layout | null
  • set layout(value: Layout | null): void

  • Get the layout for the widget.

    Notes

    The layout is single-use only. It cannot be changed after the first assignment.

    The layout is disposed automatically when the widget is disposed.

    Returns Layout | null

  • Set the layout for the widget.

    Notes

    The layout is single-use only. It cannot be changed after the first assignment.

    The layout is disposed automatically when the widget is disposed.

    Parameters

    Returns void

maximum

  • get maximum(): number
  • set maximum(value: number): void

  • Get the maximum value of the scroll bar.

    Notes

    The max size will be clamped to the range [0, Infinity].

    Returns number

  • Set the maximum value of the scroll bar.

    Notes

    The max size will be clamped to the range [0, Infinity].

    Parameters

    • value: number

    Returns void

orientation

page

  • get page(): number
  • set page(value: number): void

  • Get the page size of the scroll bar.

    Notes

    The page size is the amount of visible content in the scrolled region, expressed in data units. It determines the size of the scroll bar thumb.

    Returns number

  • Set the page size of the scroll bar.

    Notes

    The page size will be clamped to the range [0, Infinity].

    Parameters

    • value: number

    Returns void

pageRequested

  • get pageRequested(): ISignal<this, "decrement" | "increment">

  • A signal emitted when the user clicks the scroll track.

    Notes

    The payload is whether a decrease or increase is requested.

    Returns ISignal<this, "decrement" | "increment">

parent

  • get parent(): Widget | null
  • set parent(value: Widget | null): void

  • Get the parent of the widget.

    Notes

    Children are typically added to a widget by using a layout, which means user code will not normally set the parent widget directly.

    The widget will be automatically removed from its old parent.

    This is a no-op if there is no effective parent change.

    Returns Widget | null

  • Set the parent of the widget.

    Notes

    Children are typically added to a widget by using a layout, which means user code will not normally set the parent widget directly.

    The widget will be automatically removed from its old parent.

    This is a no-op if there is no effective parent change.

    Parameters

    Returns void

stepRequested

  • get stepRequested(): ISignal<this, "decrement" | "increment">

  • A signal emitted when the user clicks a step button.

    Notes

    The payload is whether a decrease or increase is requested.

    Returns ISignal<this, "decrement" | "increment">

thumbMoved

  • get thumbMoved(): ISignal<this, number>

  • A signal emitted when the user moves the scroll thumb.

    Notes

    The payload is the current value of the scroll bar.

    Returns ISignal<this, number>

thumbNode

  • get thumbNode(): HTMLDivElement

  • The scroll bar thumb node.

    Notes

    Modifying this node directly can lead to undefined behavior.

    Returns HTMLDivElement

title

  • The title object for the widget.

    Notes

    The title object is used by some container widgets when displaying the widget alongside some title, such as a tab panel or side bar.

    Since not all widgets will use the title, it is created on demand.

    The owner property of the title is set to this widget.

    Returns Title<Widget>

trackNode

  • get trackNode(): HTMLDivElement

  • The scroll bar track node.

    Notes

    Modifying this node directly can lead to undefined behavior.

    Returns HTMLDivElement

value

  • get value(): number
  • set value(value: number): void

  • Get the current value of the scroll bar.

    Notes

    The value will be clamped to the range [0, maximum].

    Returns number

  • Set the current value of the scroll bar.

    Notes

    The value will be clamped to the range [0, maximum].

    Parameters

    • value: number

    Returns void

Methods

Private _evtKeyDown

  • _evtKeyDown(event: KeyboardEvent): void

  • Handle the 'keydown' event for the scroll bar.

    Parameters

    • event: KeyboardEvent

    Returns void

Private _evtMouseDown

  • _evtMouseDown(event: MouseEvent): void

  • Handle the 'mousedown' event for the scroll bar.

    Parameters

    • event: MouseEvent

    Returns void

Private _evtMouseMove

  • _evtMouseMove(event: MouseEvent): void

  • Handle the 'mousemove' event for the scroll bar.

    Parameters

    • event: MouseEvent

    Returns void

Private _evtMouseUp

  • _evtMouseUp(event: MouseEvent): void

  • Handle the 'mouseup' event for the scroll bar.

    Parameters

    • event: MouseEvent

    Returns void

Private _moveThumb

  • _moveThumb(value: number): void

  • Move the thumb to the specified position.

    Parameters

    • value: number

    Returns void

Private _onRepeat

  • _onRepeat(): void

  • A timeout callback for repeating the mouse press.

    Returns void

Private _releaseMouse

  • _releaseMouse(): void

  • Release the mouse and restore the node states.

    Returns void

activate

  • activate(): void

  • Post an 'activate-request' message to the widget.

    Notes

    This is a simple convenience method for posting the message.

    Returns void

addClass

  • addClass(name: string): void

  • Add a class name to the widget's DOM node.

    Parameters

    • name: string

      The class name to add to the node.

      Notes

      If the class name is already added to the node, this is a no-op.

      The class name must not contain whitespace.

    Returns void

children

  • children(): IIterator<Widget>

  • Create an iterator over the widget's children.

    Returns IIterator<Widget>

    A new iterator over the children of the widget.

    Notes

    The widget must have a populated layout in order to have children.

    If a layout is not installed, the returned iterator will be empty.

clearFlag

  • clearFlag(flag: Flag): void

  • Clear the given widget flag.

    Notes

    This will not typically be called directly by user code.

    Parameters

    Returns void

close

  • close(): void

  • Send a 'close-request' message to the widget.

    Notes

    This is a simple convenience method for sending the message.

    Returns void

contains

  • contains(widget: Widget): boolean

  • Test whether a widget is a descendant of this widget.

    Parameters

    • widget: Widget

      The descendant widget of interest.

    Returns boolean

    true if the widget is a descendant, false otherwise.

dispose

  • dispose(): void

  • Dispose of the widget and its descendant widgets.

    Notes

    It is unsafe to use the widget after it has been disposed.

    All calls made to this method after the first are a no-op.

    Returns void

fit

  • fit(): void

  • Post a 'fit-request' message to the widget.

    Notes

    This is a simple convenience method for posting the message.

    Returns void

handleEvent

  • handleEvent(event: Event): void

  • Handle the DOM events for the scroll bar.

    Parameters

    • event: Event

      The DOM event sent to the scroll bar.

      Notes

      This method implements the DOM EventListener interface and is called in response to events on the scroll bar's DOM node.

      This should not be called directly by user code.

    Returns void

hasClass

  • hasClass(name: string): boolean

  • Test whether the widget's DOM node has the given class name.

    Parameters

    • name: string

      The class name of interest.

    Returns boolean

    true if the node has the class, false otherwise.

hide

  • hide(): void

  • Hide the widget and make it hidden to its parent widget.

    Notes

    This causes the isHidden property to be true.

    If the widget is explicitly hidden, this is a no-op.

    Returns void

Protected notifyLayout

  • notifyLayout(msg: Message): void

  • Invoke the message processing routine of the widget's layout.

    Parameters

    • msg: Message

      The message to dispatch to the layout.

      Notes

      This is a no-op if the widget does not have a layout.

      This will not typically be called directly by user code.

    Returns void

Protected onActivateRequest

  • onActivateRequest(msg: Message): void

  • A message handler invoked on an 'activate-request' message.

    Notes

    The default implementation of this handler is a no-op.

    Parameters

    • msg: Message

    Returns void

Protected onAfterAttach

  • onAfterAttach(msg: Message): void

  • A message handler invoked on an 'after-attach' message.

    Notes

    The default implementation of this handler is a no-op.

    Parameters

    • msg: Message

    Returns void

Protected onAfterDetach

  • onAfterDetach(msg: Message): void

Protected onAfterHide

  • onAfterHide(msg: Message): void

  • A message handler invoked on an 'after-hide' message.

    Notes

    The default implementation of this handler is a no-op.

    Parameters

    • msg: Message

    Returns void

Protected onAfterShow

  • onAfterShow(msg: Message): void

  • A message handler invoked on an 'after-show' message.

    Notes

    The default implementation of this handler is a no-op.

    Parameters

    • msg: Message

    Returns void

Protected onBeforeAttach

  • onBeforeAttach(msg: Message): void

Protected onBeforeDetach

  • onBeforeDetach(msg: Message): void

  • A message handler invoked on a 'before-detach' message.

    Notes

    The default implementation of this handler is a no-op.

    Parameters

    • msg: Message

    Returns void

Protected onBeforeHide

  • onBeforeHide(msg: Message): void

  • A message handler invoked on a 'before-hide' message.

    Notes

    The default implementation of this handler is a no-op.

    Parameters

    • msg: Message

    Returns void

Protected onBeforeShow

  • onBeforeShow(msg: Message): void

  • A message handler invoked on a 'before-show' message.

    Notes

    The default implementation of this handler is a no-op.

    Parameters

    • msg: Message

    Returns void

Protected onChildAdded

  • A message handler invoked on a 'child-added' message.

    Notes

    The default implementation of this handler is a no-op.

    Parameters

    Returns void

Protected onChildRemoved

Protected onCloseRequest

  • onCloseRequest(msg: Message): void

  • A message handler invoked on a 'close-request' message.

    Notes

    The default implementation unparents or detaches the widget.

    Parameters

    • msg: Message

    Returns void

Protected onFitRequest

  • onFitRequest(msg: Message): void

  • A message handler invoked on a 'fit-request' message.

    Notes

    The default implementation of this handler is a no-op.

    Parameters

    • msg: Message

    Returns void

Protected onResize

  • A message handler invoked on a 'resize' message.

    Notes

    The default implementation of this handler is a no-op.

    Parameters

    Returns void

Protected onUpdateRequest

  • onUpdateRequest(msg: Message): void

processMessage

  • processMessage(msg: Message): void

  • Process a message sent to the widget.

    Parameters

    • msg: Message

      The message sent to the widget.

      Notes

      Subclasses may reimplement this method as needed.

    Returns void

removeClass

  • removeClass(name: string): void

  • Remove a class name from the widget's DOM node.

    Parameters

    • name: string

      The class name to remove from the node.

      Notes

      If the class name is not yet added to the node, this is a no-op.

      The class name must not contain whitespace.

    Returns void

setFlag

  • setFlag(flag: Flag): void

  • Set the given widget flag.

    Notes

    This will not typically be called directly by user code.

    Parameters

    Returns void

setHidden

  • setHidden(hidden: boolean): void

  • Show or hide the widget according to a boolean value.

    Parameters

    • hidden: boolean

      true to hide the widget, or false to show it.

      Notes

      This is a convenience method for hide() and show().

    Returns void

show

  • show(): void

  • Show the widget and make it visible to its parent widget.

    Notes

    This causes the isHidden property to be false.

    If the widget is not explicitly hidden, this is a no-op.

    Returns void

testFlag

  • testFlag(flag: Flag): boolean

  • Test whether the given widget flag is set.

    Notes

    This will not typically be called directly by user code.

    Parameters

    Returns boolean

toggleClass

  • toggleClass(name: string, force?: boolean): boolean

  • Toggle a class name on the widget's DOM node.

    Parameters

    • name: string

      The class name to toggle on the node.

    • Optional force: boolean

      Whether to force add the class (true) or force remove the class (false). If not provided, the presence of the class will be toggled from its current state.

    Returns boolean

    true if the class is now present, false otherwise.

    Notes

    The class name must not contain whitespace.

update

  • update(): void

  • Post an 'update-request' message to the widget.

    Notes

    This is a simple convenience method for posting the message.

    Returns void

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