Interface OffscreenCanvas

MDN Reference

interface OffscreenCanvas {
    $destroyListeners?: any[];
    height: number;
    oncontextlost: Object;
    oncontextrestored: Object;
    width: number;
    addEventListener<K>(type, listener, options?): void;
    addEventListener(type, listener, options?): void;
    convertToBlob(options?): Promise<Blob>;
    dispatchEvent(event): boolean;
    getContext(contextId, options?): OffscreenCanvasRenderingContext2D;
    getContext(contextId, options?): ImageBitmapRenderingContext;
    getContext(contextId, options?): WebGLRenderingContext;
    getContext(contextId, options?): WebGL2RenderingContext;
    getContext(contextId, options?): OffscreenRenderingContext;
    removeEventListener<K>(type, listener, options?): void;
    removeEventListener(type, listener, options?): void;
    transferToImageBitmap(): ImageBitmap;
}

Hierarchy

Properties

$destroyListeners? height oncontextlost oncontextrestored width

Methods

addEventListener convertToBlob dispatchEvent getContext removeEventListener transferToImageBitmap

Properties

Optional $destroyListeners

$destroyListeners?: any[]

height

height: number

These attributes return the dimensions of the OffscreenCanvas object's bitmap.

They can be set, to replace the bitmap with a new, transparent black bitmap of the specified dimensions (effectively resizing it).

MDN Reference

oncontextlost

oncontextlost: Object

oncontextrestored

oncontextrestored: Object

width

width: number

These attributes return the dimensions of the OffscreenCanvas object's bitmap.

They can be set, to replace the bitmap with a new, transparent black bitmap of the specified dimensions (effectively resizing it).

MDN Reference

Methods

addEventListener

  • addEventListener<K>(type, listener, options?): void

  • Type Parameters

    Parameters

    Returns void

  • addEventListener(type, listener, options?): void

  • Parameters

    Returns void

convertToBlob

  • convertToBlob(options?): Promise<Blob>

  • Returns a promise that will fulfill with a new Blob object representing a file containing the image in the OffscreenCanvas object.

    The argument, if provided, is a dictionary that controls the encoding options of the image file to be created. The type field specifies the file format and has a default value of "image/png"; that type is also used if the requested type isn't supported. If the image format supports variable quality (such as "image/jpeg"), then the quality field is a number in the range 0.0 to 1.0 inclusive indicating the desired quality level for the resulting image.

    MDN Reference

    Parameters

    Returns Promise<Blob>

dispatchEvent

  • dispatchEvent(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

getContext

  • getContext(contextId, options?): OffscreenCanvasRenderingContext2D

  • Returns an object that exposes an API for drawing on the OffscreenCanvas object. contextId specifies the desired API: "2d", "bitmaprenderer", "webgl", or "webgl2". options is handled by that API.

    This specification defines the "2d" context below, which is similar but distinct from the "2d" context that is created from a canvas element. The WebGL specifications define the "webgl" and "webgl2" contexts. [WEBGL]

    Returns null if the canvas has already been initialized with another context type (e.g., trying to get a "2d" context after getting a "webgl" context).

    MDN Reference

    Parameters

    • contextId: "2d"
    • Optional options: any

    Returns OffscreenCanvasRenderingContext2D

  • getContext(contextId, options?): ImageBitmapRenderingContext

  • Parameters

    • contextId: "bitmaprenderer"
    • Optional options: any

    Returns ImageBitmapRenderingContext

  • getContext(contextId, options?): WebGLRenderingContext

  • Parameters

    • contextId: "webgl"
    • Optional options: any

    Returns WebGLRenderingContext

  • getContext(contextId, options?): WebGL2RenderingContext

  • Parameters

    • contextId: "webgl2"
    • Optional options: any

    Returns WebGL2RenderingContext

  • getContext(contextId, options?): OffscreenRenderingContext

  • Parameters

    Returns OffscreenRenderingContext

removeEventListener

  • removeEventListener<K>(type, listener, options?): void

  • Type Parameters

    Parameters

    Returns void

  • removeEventListener(type, listener, options?): void

  • Parameters

    Returns void

transferToImageBitmap

  • transferToImageBitmap(): ImageBitmap

  • Returns a newly created ImageBitmap object with the image in the OffscreenCanvas object. The image in the OffscreenCanvas object is replaced with a new blank image.

    MDN Reference

    Returns ImageBitmap

Settings

Member Visibility

Theme

On This Page

$destroyListenersheightoncontextlostoncontextrestoredwidthaddEventListenerconvertToBlobdispatchEventgetContextremoveEventListenertransferToImageBitmap