CanvasRenderer

Generic renderer using ResponsiveCanvas

Generic Renderer utilizing ResponsiveCanvas. Refer to their documentation for more details. CanvasRenderer can have several layers and there’re two basic usage patterns. Use separate layers for video and scene and effectively render scene on top of the video stream. Advantage of this approach is that image and scene can be processed independently and one can apply different effects or postprocessing. This pattern is also easier to implement. Or one can use only one canvas layer and embed video stream into the scene as object via a texture or background component. This approach will have more complex implementation dependent on particular renderer. On the other hand, rendering effects affecting the whole scene will also apply to the video stream. This can improve performance and allows advanced rendering/postprocessing techniques to be used.

Extends

• PluginRenderer<ResultT>

Extended by

• VideoRenderer
• ShaderRenderer

Type Parameters

• ResultT extends object = object

Type of processing results

Constructors

new CanvasRenderer()

new CanvasRenderer<ResultT>(params): CanvasRenderer<ResultT>

Constructor

Parameters

• params: CanvasParams

Parameters of responsive canvas

Returns

CanvasRenderer<ResultT>

Overrides

PluginRenderer.constructor

Properties

cameraAngle

protected cameraAngle: number

Camera vertical angle in radians

Inherited from

PluginRenderer.cameraAngle

---

cameraRatio

protected cameraRatio: number

Camera aspect ratio

Inherited from

PluginRenderer.cameraRatio

---

canvas

canvas: ResponsiveCanvas

Responsive canvas

---

loaded

protected loaded: boolean = false

Loaded state

Inherited from

PluginRenderer.loaded

---

padCtx

protected padCtx: [null | CanvasRenderingContext2D, null | CanvasRenderingContext2D]

Drawing context of padding canvases

---

plugins

protected plugins: Plugin<ResultT>[] = []

Attached plugins

Inherited from

PluginRenderer.plugins

---

videoRatio

protected videoRatio: number

Aspect ratio of input video

Inherited from

PluginRenderer.videoRatio

---

videoSize

protected videoSize: Size

Resolution of input video

Inherited from

PluginRenderer.videoSize

Methods

addListener()

addListener<E>(event, listener): this

Adds the listener function to the end of the listeners array

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

• listener: RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

PluginRenderer.addListener

---

addPlugin()

addPlugin(plugin): Promise<void>

Add render plugin

Initializes the plugin if it’s not loaded yet but renderer is ready. Renderer takes ownership of the plugin instance meaning it will release it when plugin is detached or renderer is disposed itself.

Parameters

• plugin: Plugin<ResultT>

Returns

Promise<void>

Inherited from

PluginRenderer.addPlugin

---

dispose()

dispose(): void

Dispose renderer object

Extended to dispose responsive canvas

Returns

void

Overrides

PluginRenderer.dispose

---

emit()

emit<E>(event, …args): boolean

Synchronously calls each of the listeners registered for the event

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

• …args: Args<RendererEvents[E]>

Arguments passed to the listeners

Returns

boolean

True if the event had listeners, False otherwise

Inherited from

PluginRenderer.emit

---

eventNames()

eventNames(): (string | symbol)[]

List of emitter’s events

Returns

(string | symbol)[]

List of emitter’s events

Inherited from

PluginRenderer.eventNames

---

getMaxListeners()

getMaxListeners(): number

Maximum number of listeners per event

Returns

number

Maximum number of listeners per event

Inherited from

PluginRenderer.getMaxListeners

---

listenerCount()

listenerCount<E>(event): number

The number of listeners listening to the event

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

Returns

number

Number of listeners

Inherited from

PluginRenderer.listenerCount

---

listeners()

listeners<E>(event): Function[]

Copy of the array of listeners for the event

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

Returns

Function[]

Copy of the listeners array

Inherited from

PluginRenderer.listeners

---

load()

load(): Promise<void>

Initialize renderer

Initializes all attached plugins.

Returns

Promise<void>

Promise resolving when initialization is finished

Inherited from

PluginRenderer.load

---

off()

off<E>(event, listener): this

Removes the listener from the listener array for the event

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

• listener: RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

PluginRenderer.off

---

on()

on<E>(event, listener): this

Adds the listener function to the event

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

• listener: RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

PluginRenderer.on

---

once()

once<E>(event, listener): this

Adds a one-time listener function for the event

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

• listener: RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

PluginRenderer.once

---

prependListener()

prependListener<E>(event, listener): this

Adds the listener function to the beginning of the listeners array

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

• listener: RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

PluginRenderer.prependListener

---

prependOnceListener()

prependOnceListener<E>(event, listener): this

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

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

• listener: RendererEvents[E]

The callback function

Returns

this

Inherited from

PluginRenderer.prependOnceListener

---

rawListeners()

rawListeners<E>(event): Function[]

Copy of the array of listeners for the event including wrappers

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

Returns

Function[]

Copy of the listeners array

Inherited from

PluginRenderer.rawListeners

---

removeAllListeners()

removeAllListeners<E>(event?): this

Removes all listeners, or those of the specified event

Type Parameters

• E extends keyof RendererEvents

Parameters

• event?: E

The name of the event

Returns

this

This EventEmitter

Inherited from

PluginRenderer.removeAllListeners

---

removeAllPlugins()

removeAllPlugins(): void

Remove all render plugins

Renderer will dispose all plugins before detaching them.

Returns

void

Inherited from

PluginRenderer.removeAllPlugins

---

removeListener()

removeListener<E>(event, listener): this

Removes the specified listener from the listener array

Type Parameters

• E extends keyof RendererEvents

Parameters

• event: E

The name of the event

• listener: RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

PluginRenderer.removeListener

---

removePlugin()

removePlugin(plugin): void

Remove render plugin

Renderer will dispose the plugin before detaching it.

Parameters

• plugin: Plugin<ResultT>

Returns

void

Inherited from

PluginRenderer.removePlugin

---

setMaxListeners()

setMaxListeners(n): this

Sets maximum number of listeners per event

Parameters

• n: number

Maximum number of listeners

Returns

this

This EventEmitter

Inherited from

PluginRenderer.setMaxListeners

---

setMirror()

setMirror(mirror): void

Set mirror mode

CanvasRenderer sets mirror mode of ResponsiveCanvas.

Parameters

• mirror: boolean

Mirror the output

Returns

void

---

setMode()

setMode(mode): void

Set fitting mode

CanvasRenderer sets fitting mode of ResponsiveCanvas.

Parameters

• mode: CanvasMode

Fitting mode

Returns

void

---

setupCamera()

setupCamera(ratio, angle): void

Set camera parameters

Callback sets up all attached plugins.

Parameters

• ratio: number

Camera aspect ratio

• angle: number

Camera vertical angle in radians

Returns

void

Inherited from

PluginRenderer.setupCamera

---

setupPadding()

protected setupPadding(): void

Setup padding canvases

Callback sets up size of padding canvases.

Returns

void

---

setupVideo()

setupVideo(size, ratio?): void

Set video parameters

Callback passes aspect ratio to responsive canvas.

Parameters

• size: Size

Resolution of input video

• ratio?: number

Aspect ration of input video

Returns

void

Overrides

PluginRenderer.setupVideo

---

unload()

unload(): void

Reset renderer

Resets all attached plugins.

Returns

void

Inherited from

PluginRenderer.unload

---

update()

update(result, stream): Promise<void>

Update the scene

Updates all attached plugins.

Parameters

• result: ResultT

Results of video processing

• stream: HTMLCanvasElement

Captured video frame

Returns

Promise<void>

Promise resolving when update is finished

Inherited from

PluginRenderer.update

---

updatePads()

protected updatePads(stream): void

Update padding canvases

Updates padding canvases using portions of video frame.

Parameters

• stream: HTMLCanvasElement

Captured video frame

Returns

void

---

updatePlugins()

protected updatePlugins(result, stream): Promise<void>

Update attached plugins

Calls update() of all attached plugins.

Parameters

• result: ResultT

Results of video processing

• stream: HTMLCanvasElement

Captured video frame

Returns

Promise<void>

Promise resolving when update is finished

Inherited from

PluginRenderer.updatePlugins

---

updateScene()

protected updateScene(): void

Update and render the scene

Virtual method updating and rendering the scene. Overridden by implementation of derived renderer.

Returns

void

Inherited from

PluginRenderer.updateScene

---

updateVideo()

protected updateVideo(stream): void

Update the video layer

Updates padding canvases using portions of video frame.

Parameters

• stream: HTMLCanvasElement

Captured video frame

Returns

void

Overrides

PluginRenderer.updateVideo