Class: AsyncEngine<ResultT, ParamsT, ProcessorT>

@geenee/armature.AsyncEngine

Generic asynchronous engine

AsyncEngine is extension of the Engine that does processing in the background. Its pipeline provides for better performance and more stable frames per second. By using async engine you can achieve smoother and faster experience. AsyncEngine and Engine are compatible, you can use any of them without additional code adjustments.

Type parameters

Name	Type	Description
ResultT	extends Object	Type of processing results
ParamsT	extends ProcParams	Type of processor parameters
ProcessorT	extends Processor<ResultT, ParamsT>	Type of processor

Hierarchy

• Engine<ResultT, ParamsT, ProcessorT>

  ↳ AsyncEngine

Constructors

constructor

• new AsyncEngine<ResultT, ParamsT, ProcessorT>(Processor, engineParams?, Source?)

Constructor

Type parameters

Name	Type	Description
ResultT	extends Object	Type of processing results
ParamsT	extends ProcParams	Type of processor parameters
ProcessorT	extends Processor<ResultT, ParamsT, ProcessorT>	Type of processor

Parameters

Name	Type	Default value	Description
Processor	() => ProcessorT	undefined	Processor class or its constructor
engineParams?	EngineParams	undefined	Parameters of the engine
Source	() => VideoSource	VideoCapture	Video source class or its constructor

Inherited from

Engine.constructor

Properties

engineParams

• Protected Optional engineParams: EngineParams

Inherited from

Engine.engineParams

---

processCanvas

• Protected Optional processCanvas: HTMLCanvasElement

Shallow copy of canvas with video for processors

Inherited from

Engine.processCanvas

---

processSize

• Protected processSize: Size

Size of video for processors

Inherited from

Engine.processSize

---

processor

• Protected processor: ProcessorT

Processor utilized by the engine

Inherited from

Engine.processor

---

renderers

• Protected renderers: Renderer<ResultT>[] = []

Renderer attached to the engine

Inherited from

Engine.renderers

---

resizeBuffer

• Protected Optional resizeBuffer: ImageBuffer

Buffer to resize frames

Inherited from

Engine.resizeBuffer

---

resizeEnabled

• Protected resizeEnabled: boolean = false

Original stream is resized

Inherited from

Engine.resizeEnabled

---

streamCanvas

• Protected Optional streamCanvas: HTMLCanvasElement

Shallow copy of canvas with video for renderers

Inherited from

Engine.streamCanvas

---

streamSize

• Protected streamSize: Size

Size of video for renderers

Inherited from

Engine.streamSize

---

video

• Protected video: VideoSource

Video source instance

Inherited from

Engine.video

---

videoRatio

• Protected videoRatio: number

Ratio of video stream

Inherited from

Engine.videoRatio

Methods

addListener

▸ addListener<E>(event, listener): AsyncEngine<ResultT, ParamsT, ProcessorT>

Adds the listener function to the end of the listeners array

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event
listener	EngineEvents[E]	The callback function

Returns

AsyncEngine<ResultT, ParamsT, ProcessorT>

This EventEmitter

Inherited from

Engine.addListener

---

addRenderer

▸ addRenderer(renderer): Promise<void>

Attach Renderer to the engine

Parameters

Name	Type	Description
renderer	Renderer<ResultT>	Object to be attached

Returns

Promise<void>

Inherited from

Engine.addRenderer

---

emit

▸ emit<E>(event, ...args): boolean

Synchronously calls each of the listeners registered for the event

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event
...args	Args<EngineEvents[E]>	Arguments passed to the listeners

Returns

boolean

True if the event had listeners, False otherwise

Inherited from

Engine.emit

---

enqueue

▸ Protected enqueue(): void

Enqueue the next iteration

Returns

void

Inherited from

Engine.enqueue

---

eventNames

▸ eventNames(): (string | symbol)[]

List of emitter's events

Returns

(string | symbol)[]

List of emitter's events

Inherited from

Engine.eventNames

---

getMaxListeners

▸ getMaxListeners(): number

Maximum number of listeners per event

Returns

number

Maximum number of listeners per event

Inherited from

Engine.getMaxListeners

---

init

▸ init(procParams): Promise<boolean>

Initialize engine. Sets up processor.

The SDK access token is required parameter that authenticates the user and enables the SDK on the current url. By default, path to required wasm modules provided with SDK packages is the current url. You can change the root path to wasms passing root parameter.

Parameters

Name	Type
procParams	ParamsT

Returns

Promise<boolean>

Status of initialization

Inherited from

Engine.init

---

iterate

▸ Protected iterate(): Promise<void>

Iterate

Overridden for asynchronous processing.

Returns

Promise<void>

Overrides

Engine.iterate

---

listenerCount

▸ listenerCount<E>(event): number

The number of listeners listening to the event

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event

Returns

number

Number of listeners

Inherited from

Engine.listenerCount

---

listeners

▸ listeners<E>(event): Function[]

Copy of the array of listeners for the event

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event

Returns

Function[]

Copy of the listeners array

Inherited from

Engine.listeners

---

off

▸ off<E>(event, listener): AsyncEngine<ResultT, ParamsT, ProcessorT>

Removes the listener from the listener array for the event

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event
listener	EngineEvents[E]	The callback function

Returns

AsyncEngine<ResultT, ParamsT, ProcessorT>

This EventEmitter

Inherited from

Engine.off

---

on

▸ on<E>(event, listener): AsyncEngine<ResultT, ParamsT, ProcessorT>

Adds the listener function to the event

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event
listener	EngineEvents[E]	The callback function

Returns

AsyncEngine<ResultT, ParamsT, ProcessorT>

This EventEmitter

Inherited from

Engine.on

---

once

▸ once<E>(event, listener): AsyncEngine<ResultT, ParamsT, ProcessorT>

Adds a one-time listener function for the event

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event
listener	EngineEvents[E]	The callback function

Returns

AsyncEngine<ResultT, ParamsT, ProcessorT>

This EventEmitter

Inherited from

Engine.once

---

pause

▸ pause(): void

Pause pipeline.

Nothing happens if pipeline is not started yet.

Returns

void

Inherited from

Engine.pause

---

prependListener

▸ prependListener<E>(event, listener): AsyncEngine<ResultT, ParamsT, ProcessorT>

Adds the listener function to the beginning of the listeners array

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event
listener	EngineEvents[E]	The callback function

Returns

AsyncEngine<ResultT, ParamsT, ProcessorT>

This EventEmitter

Inherited from

Engine.prependListener

---

prependOnceListener

▸ prependOnceListener<E>(event, listener): AsyncEngine<ResultT, ParamsT, ProcessorT>

Adds a one-time listener function to the beginning of the listeners array

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event
listener	EngineEvents[E]	The callback function

Returns

AsyncEngine<ResultT, ParamsT, ProcessorT>

Inherited from

Engine.prependOnceListener

---

rawListeners

▸ rawListeners<E>(event): Function[]

Copy of the array of listeners for the event including wrappers

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event

Returns

Function[]

Copy of the listeners array

Inherited from

Engine.rawListeners

---

removeAllListeners

▸ removeAllListeners<E>(event?): AsyncEngine<ResultT, ParamsT, ProcessorT>

Removes all listeners, or those of the specified event

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event?	E	The name of the event

Returns

AsyncEngine<ResultT, ParamsT, ProcessorT>

This EventEmitter

Inherited from

Engine.removeAllListeners

---

removeListener

▸ removeListener<E>(event, listener): AsyncEngine<ResultT, ParamsT, ProcessorT>

Removes the specified listener from the listener array

Type parameters

Name	Type
E	extends keyof EngineEvents

Parameters

Name	Type	Description
event	E	The name of the event
listener	EngineEvents[E]	The callback function

Returns

AsyncEngine<ResultT, ParamsT, ProcessorT>

This EventEmitter

Inherited from

Engine.removeListener

---

removeRenderer

▸ removeRenderer(renderer): void

Remove attached Renderer

Parameters

Name	Type	Description
renderer	Renderer<ResultT>	Renderer to be removed

Returns

void

Inherited from

Engine.removeRenderer

---

reset

▸ reset(): void

Reset pipeline

Stops pipeline, resets video capture and processor. After reset one needs to reinitialize video capture calling setup() before pipeline can be started again.

Returns

void

Inherited from

Engine.reset

---

resizeVideo

▸ Protected resizeVideo(size): void

Callback called when video resolution is changed

Parameters

Name	Type	Description
size	Size	Size of the video

Returns

void

Inherited from

Engine.resizeVideo

---

setMaxListeners

▸ setMaxListeners(n): AsyncEngine<ResultT, ParamsT, ProcessorT>

Sets maximum number of listeners per event

Parameters

Name	Type	Description
n	number	Maximum number of listeners

Returns

AsyncEngine<ResultT, ParamsT, ProcessorT>

This EventEmitter

Inherited from

Engine.setMaxListeners

---

setup

▸ setup(videoParams?): Promise<boolean>

Setup engine. Initializes video capture.

Video capture can be setup by simplified VideoParams opening default front/rear camera with provided resolution, custom MediaStreamConstraints providing the most flexible way to setup video stream (e.g. set deviceId), or external MediaStream allowing custom video sources (e.g. from file).

Parameters

Name	Type	Description
videoParams?	VideoSourceParams	Parameters of video capture

Returns

Promise<boolean>

Status of initialization

Inherited from

Engine.setup

---

setupProcessor

▸ Protected setupProcessor(procParams): Promise<boolean>

Setup processor

Parameters

Name	Type
procParams	ParamsT

Returns

Promise<boolean>

Inherited from

Engine.setupProcessor

---

setupSize

▸ Protected setupSize(size): Promise<void>

Setup video size

Parameters

Name	Type
size	Size

Returns

Promise<void>

Inherited from

Engine.setupSize

---

setupVideo

▸ Protected setupVideo(videoParams?): Promise<boolean>

Setup video capture

Parameters

Name	Type
videoParams?	VideoSourceParams

Returns

Promise<boolean>

Inherited from

Engine.setupVideo

---

start

▸ start(): Promise<void>

Start pipeline.

Pipeline can be started only after successful init and setup.

Returns

Promise<void>

Inherited from

Engine.start