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    Interface OffscreenCanvas

    When using the element or the Canvas API, rendering, animation, and user interaction usually happen on the main execution thread of a web application. The computation relating to canvas animations and rendering can have a significant impact on application performance.

    MDN Reference

    interface OffscreenCanvas {
        height: number;
        oncontextlost: ((this: OffscreenCanvas, ev: Event) => any) | null;
        oncontextrestored: ((this: OffscreenCanvas, ev: Event) => any) | null;
        width: number;
        addEventListener<K extends keyof OffscreenCanvasEventMap>(
            type: K,
            listener: (this: OffscreenCanvas, ev: OffscreenCanvasEventMap[K]) => any,
            options?: boolean | AddEventListenerOptions,
        ): void;
        addEventListener(
            type: string,
            listener: EventListenerOrEventListenerObject,
            options?: boolean | AddEventListenerOptions,
        ): void;
        convertToBlob(options?: ImageEncodeOptions): Promise<Blob>;
        dispatchEvent(event: Event): boolean;
        getContext(
            contextId: "2d",
            options?: any,
        ): OffscreenCanvasRenderingContext2D | null;
        getContext(
            contextId: "bitmaprenderer",
            options?: any,
        ): ImageBitmapRenderingContext | null;
        getContext(contextId: "webgl", options?: any): WebGLRenderingContext | null;
        getContext(
            contextId: "webgl2",
            options?: any,
        ): WebGL2RenderingContext | null;
        getContext(
            contextId: OffscreenRenderingContextId,
            options?: any,
        ): OffscreenRenderingContext | null;
        removeEventListener<K extends keyof OffscreenCanvasEventMap>(
            type: K,
            listener: (this: OffscreenCanvas, ev: OffscreenCanvasEventMap[K]) => any,
            options?: boolean | EventListenerOptions,
        ): void;
        removeEventListener(
            type: string,
            listener: EventListenerOrEventListenerObject,
            options?: boolean | EventListenerOptions,
        ): void;
        transferToImageBitmap(): ImageBitmap;
    }

    Hierarchy (View Summary)

    Index

    Properties

    height oncontextlost oncontextrestored width

    Methods

    addEventListener convertToBlob dispatchEvent getContext removeEventListener transferToImageBitmap

    Properties

    height: number

    The height property returns and sets the height of an OffscreenCanvas object.

    MDN Reference

    oncontextlost: ((this: OffscreenCanvas, ev: Event) => any) | null

    MDN Reference

    oncontextrestored: ((this: OffscreenCanvas, ev: Event) => any) | null

    MDN Reference

    width: number

    The width property returns and sets the width of an OffscreenCanvas object.

    MDN Reference

    Methods

    • The dispatchEvent() method of the EventTarget sends an Event to the object, (synchronously) invoking the affected event listeners in the appropriate order. The normal event processing rules (including the capturing and optional bubbling phase) also apply to events dispatched manually with dispatchEvent().

      MDN Reference

      Parameters

      Returns boolean

    • The OffscreenCanvas.transferToImageBitmap() method creates an ImageBitmap object from the most recently rendered image of the OffscreenCanvas. The OffscreenCanvas allocates a new image for its subsequent rendering.

      MDN Reference

      Returns ImageBitmap

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