Class CanvasWorkerInstance<TCanvas, TApplicationOptions, TKernel>

The canvas worker instance handles a web worker instance in worker instance itself, and handles a feedback channel to the host application.

It provides a thin abstraction over the web worker IPC messaging.

// Construct inside of worker from global scope and rendering kernel class.
const worker = new CanvasWorkerInstance(self, RenderKernel);
// Listen to custom events (messages) you send from the host.
worker.addEventListener("fade", () => worker.renderKernel?.fadeOut());

Type Parameters

Hierarchy

Constructors

constructor

Properties

canvas id offscreenCanvas offscreenContext renderKernel renderLoop self

Methods

addEventListener dispatchEvent postMessage reconfigure removeEventListener render start

Constructors

constructor

Properties

canvas

canvas: undefined | TCanvas

The canvas element we're presenting to.

id

id: string

The ID of the worker.

offscreenCanvas

offscreenCanvas: undefined | OffscreenCanvas

The offscreen canvas we're rendering to.

offscreenContext

offscreenContext: undefined | OffscreenCanvasRenderingContext2D

Our rendering context to draw to.

renderKernel

renderKernel: undefined | TKernel

The rendering kernel, which produces frames, and renders them to our offscreen canvas.

renderLoop

renderLoop: undefined | RenderLoop

Manages frame rendering timing.

Readonlyself

self: typeof globalThis

The global scope of the worker.

Methods

addEventListener

  • addEventListener(
        type: string,
        callback: null | EventListenerOrEventListenerObject,
        options?: boolean | AddEventListenerOptions,
    ): void

  • Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

    The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

    When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

    When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.

    When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

    If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

    The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

    MDN Reference

    Parameters

    • type: string
    • callback: null | EventListenerOrEventListenerObject
    • Optionaloptions: boolean | AddEventListenerOptions

    Returns void

dispatchEvent

  • dispatchEvent(event: Event): boolean

  • Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, and false otherwise.

    MDN Reference

    Parameters

    Returns boolean

postMessage

reconfigure

removeEventListener

  • removeEventListener(
        type: string,
        callback: null | EventListenerOrEventListenerObject,
        options?: boolean | EventListenerOptions,
    ): void

  • Removes the event listener in target's event listener list with the same type, callback, and options.

    MDN Reference

    Parameters

    • type: string
    • callback: null | EventListenerOrEventListenerObject
    • Optionaloptions: boolean | EventListenerOptions

    Returns void

render

start

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