Interface OffscreenCanvas

When using the canvas element or the Canvas API, rendering, animation, and user interaction usually happen on the main execution thread of a web application.

MDN Reference

interface OffscreenCanvas {
    height: number;
    oncontextlost: null | ((this: OffscreenCanvas, ev: Event) => any);
    oncontextrestored: null | ((this: OffscreenCanvas, ev: Event) => any);
    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,
    ): null | OffscreenCanvasRenderingContext2D;
    getContext(
        contextId: "bitmaprenderer",
        options?: any,
    ): null | ImageBitmapRenderingContext;
    getContext(contextId: "webgl", options?: any): null | WebGLRenderingContext;
    getContext(
        contextId: "webgl2",
        options?: any,
    ): null | WebGL2RenderingContext;
    getContext(
        contextId: OffscreenRenderingContextId,
        options?: any,
    ): null | OffscreenRenderingContext;
    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

EventTarget
- OffscreenCanvas

Index

Properties

height oncontextlost oncontextrestored width

Methods

addEventListener convertToBlob dispatchEvent getContext removeEventListener transferToImageBitmap

Properties

height

height: number

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

MDN Reference

oncontextlost

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

MDN Reference

oncontextrestored

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

MDN Reference

width

width: number

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

MDN Reference

Methods

addEventListener

addEventListener<K extends keyof OffscreenCanvasEventMap>(
    type: K,
    listener: (this: OffscreenCanvas, ev: OffscreenCanvasEventMap[K]) => any,
    options?: boolean | AddEventListenerOptions,
): void
The addEventListener() method of the EventTarget interface sets up a function that will be called whenever the specified event is delivered to the target.

MDN Reference
Type Parameters
- K extends keyof OffscreenCanvasEventMap
Parameters
- type: K
- listener: (this: OffscreenCanvas, ev: OffscreenCanvasEventMap[K]) => any
- Optionaloptions: boolean | AddEventListenerOptions
Returns void
Overrides EventTarget.addEventListener
addEventListener(
    type: string,
    listener: EventListenerOrEventListenerObject,
    options?: boolean | AddEventListenerOptions,
): void
The addEventListener() method of the EventTarget interface sets up a function that will be called whenever the specified event is delivered to the target.

MDN Reference
Parameters
- type: string
- listener: EventListenerOrEventListenerObject
- Optionaloptions: boolean | AddEventListenerOptions
Returns void
Overrides EventTarget.addEventListener

convertToBlob

convertToBlob(options?: ImageEncodeOptions): Promise<Blob>
The OffscreenCanvas.convertToBlob() method creates a Blob object representing the image contained in the canvas.

MDN Reference
Parameters
- Optionaloptions: ImageEncodeOptions
Returns Promise<Blob>

dispatchEvent

dispatchEvent(event: Event): boolean
The dispatchEvent() method of the EventTarget sends an Event to the object, (synchronously) invoking the affected event listeners in the appropriate order.

MDN Reference
Parameters
- event: Event
Returns boolean
Inherited from EventTarget.dispatchEvent

getContext

getContext(
contextId: "2d",
options?: any,
): null | OffscreenCanvasRenderingContext2D
The OffscreenCanvas.getContext() method returns a drawing context for an offscreen canvas, or null if the context identifier is not supported, or the offscreen canvas has already been set to a different context mode.

MDN Reference
Parameters
- contextId: "2d"
- Optionaloptions: any
Returns null | OffscreenCanvasRenderingContext2D
getContext(
contextId: "bitmaprenderer",
options?: any,
): null | ImageBitmapRenderingContext
Parameters
- contextId: "bitmaprenderer"
- Optionaloptions: any
Returns null | ImageBitmapRenderingContext
getContext(contextId: "webgl", options?: any): null | WebGLRenderingContext
Parameters
- contextId: "webgl"
- Optionaloptions: any
Returns null | WebGLRenderingContext
getContext(contextId: "webgl2", options?: any): null | WebGL2RenderingContext
Parameters
- contextId: "webgl2"
- Optionaloptions: any
Returns null | WebGL2RenderingContext
getContext(
contextId: OffscreenRenderingContextId,
options?: any,
): null | OffscreenRenderingContext
Parameters
- contextId: OffscreenRenderingContextId
- Optionaloptions: any
Returns null | OffscreenRenderingContext

removeEventListener

removeEventListener<K extends keyof OffscreenCanvasEventMap>(
    type: K,
    listener: (this: OffscreenCanvas, ev: OffscreenCanvasEventMap[K]) => any,
    options?: boolean | EventListenerOptions,
): void
The removeEventListener() method of the EventTarget interface removes an event listener previously registered with EventTarget.addEventListener() from the target.

MDN Reference
Type Parameters
- K extends keyof OffscreenCanvasEventMap
Parameters
- type: K
- listener: (this: OffscreenCanvas, ev: OffscreenCanvasEventMap[K]) => any
- Optionaloptions: boolean | EventListenerOptions
Returns void
Overrides EventTarget.removeEventListener
removeEventListener(
    type: string,
    listener: EventListenerOrEventListenerObject,
    options?: boolean | EventListenerOptions,
): void
The removeEventListener() method of the EventTarget interface removes an event listener previously registered with EventTarget.addEventListener() from the target.

MDN Reference
Parameters
- type: string
- listener: EventListenerOrEventListenerObject
- Optionaloptions: boolean | EventListenerOptions
Returns void
Overrides EventTarget.removeEventListener

transferToImageBitmap

transferToImageBitmap(): ImageBitmap
The OffscreenCanvas.transferToImageBitmap() method creates an ImageBitmap object from the most recently rendered image of the OffscreenCanvas.

MDN Reference

Returns ImageBitmap

Interface OffscreenCanvas

Hierarchy

Index

Properties

Methods

Properties

height

oncontextlost

oncontextrestored

width

Methods

addEventListener

Type Parameters

Parameters

Returns void

Parameters

Returns void

convertToBlob

Parameters

Returns Promise<Blob>

dispatchEvent

Parameters

Returns boolean

getContext

Parameters

Returns null | OffscreenCanvasRenderingContext2D

Parameters

Returns null | ImageBitmapRenderingContext

Parameters

Returns null | WebGLRenderingContext

Parameters

Returns null | WebGL2RenderingContext

Parameters

Returns null | OffscreenRenderingContext

removeEventListener

Type Parameters

Parameters

Returns void

Parameters

Returns void

transferToImageBitmap

Returns ImageBitmap

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