Mirror Engine
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Mirror Engine API


Mirror Engine API / ScrollbarComponent

Class: ScrollbarComponent

A ScrollbarComponent enables a group of entities to behave like a draggable scrollbar.

Extends

  • Component

Properties

entity

entity: Entity

The Entity that this Component is attached to.

Inherited from

Component.entity

system

system: ComponentSystem

The ComponentSystem used to create this Component.

Inherited from

Component.system

enabled

Get Signature

get enabled(): boolean

Gets the enabled state of the component.

Returns

boolean

Set Signature

set enabled(arg: boolean): void

Sets the enabled state of the component.

Parameters
arg

boolean

Returns

void

Overrides

Component.enabled

handleEntity

Get Signature

get handleEntity(): null | Entity

Gets the entity to be used as the scrollbar handle.

Returns

null | Entity

Set Signature

set handleEntity(arg: null | Entity): void

Sets the entity to be used as the scrollbar handle. This entity must have a ScrollbarComponent.

Parameters
arg

null | Entity

Returns

void


handleSize

Get Signature

get handleSize(): number

Gets the size of the handle relative to the size of the track.

Returns

number

Set Signature

set handleSize(arg: number): void

Sets the size of the handle relative to the size of the track, in the range 0 to 1. For a vertical scrollbar, a value of 1 means that the handle will take up the full height of the track.

Parameters
arg

number

Returns

void


orientation

Get Signature

get orientation(): number

Gets whether the scrollbar moves horizontally or vertically.

Returns

number

Set Signature

set orientation(arg: number): void

Sets whether the scrollbar moves horizontally or vertically. Can be:

Defaults to ORIENTATION_HORIZONTAL.

Parameters
arg

number

Returns

void


value

Get Signature

get value(): number

Gets the current position value of the scrollbar.

Returns

number

Set Signature

set value(arg: number): void

Sets the current position value of the scrollbar, in the range 0 to 1. Defaults to 0.

Parameters
arg

number

Returns

void

Methods

fire()

fire(
   name: string,
   arg1?: any,
   arg2?: any,
   arg3?: any,
   arg4?: any,
   arg5?: any,
   arg6?: any,
   arg7?: any,
   arg8?: any): EventHandler

Fire an event, all additional arguments are passed on to the event listener.

Parameters

name

string

Name of event to fire.

arg1?

any

First argument that is passed to the event handler.

arg2?

any

Second argument that is passed to the event handler.

arg3?

any

Third argument that is passed to the event handler.

arg4?

any

Fourth argument that is passed to the event handler.

arg5?

any

Fifth argument that is passed to the event handler.

arg6?

any

Sixth argument that is passed to the event handler.

arg7?

any

Seventh argument that is passed to the event handler.

arg8?

any

Eighth argument that is passed to the event handler.

Returns

EventHandler

Self for chaining.

Example

obj.fire('test', 'This is the message')

Inherited from

Component.fire

hasEvent()

hasEvent(name: string): boolean

Test if there are any handlers bound to an event name.

Parameters

name

string

The name of the event to test.

Returns

boolean

True if the object has handlers bound to the specified event name.

Example

obj.on('test', () => {}) // bind an event to 'test'
obj.hasEvent('test') // returns true
obj.hasEvent('hello') // returns false

Inherited from

Component.hasEvent

off()

off(
   name?: string,
   callback?: HandleEventCallback,
   scope?: any): EventHandler

Detach an event handler from an event. If callback is not provided then all callbacks are unbound from the event, if scope is not provided then all events with the callback will be unbound.

Parameters

name?

string

Name of the event to unbind.

callback?

HandleEventCallback

Function to be unbound.

scope?

any

Scope that was used as the this when the event is fired.

Returns

EventHandler

Self for chaining.

Example

const handler = () => {}
obj.on('test', handler)

obj.off() // Removes all events
obj.off('test') // Removes all events called 'test'
obj.off('test', handler) // Removes all handler functions, called 'test'
obj.off('test', handler, this) // Removes all handler functions, called 'test' with scope this

Inherited from

Component.off

on()

on(
   name: string,
   callback: HandleEventCallback,
   scope?: any): EventHandle

Attach an event handler to an event.

Parameters

name

string

Name of the event to bind the callback to.

callback

HandleEventCallback

Function that is called when event is fired. Note the callback is limited to 8 arguments.

scope?

any = ...

Object to use as 'this' when the event is fired, defaults to current this.

Returns

EventHandle

Can be used for removing event in the future.

Examples

obj.on('test', (a, b) => {
  console.log(a + b)
})
obj.fire('test', 1, 2) // prints 3 to the console
const evt = obj.on('test', (a, b) => {
  console.log(a + b)
})
// some time later
evt.off()

Inherited from

Component.on

once()

once(
   name: string,
   callback: HandleEventCallback,
   scope?: any): EventHandle

Attach an event handler to an event. This handler will be removed after being fired once.

Parameters

name

string

Name of the event to bind the callback to.

callback

HandleEventCallback

Function that is called when event is fired. Note the callback is limited to 8 arguments.

scope?

any = ...

Object to use as 'this' when the event is fired, defaults to current this.

Returns

EventHandle

  • can be used for removing event in the future.

Example

obj.once('test', (a, b) => {
  console.log(a + b)
})
obj.fire('test', 1, 2) // prints 3 to the console
obj.fire('test', 1, 2) // not going to get handled

Inherited from

Component.once

Events

EVENT_SETVALUE

static EVENT_SETVALUE: string = 'set:value';

Fired whenever the scroll value changes. The handler is passed a number representing the current scroll value.

Example

entity.scrollbar.on('set:value', (value) => {
  console.log(`Scroll value is now ${'${value}'}`)
})
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