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).

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).

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.

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).

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.