getContext
fun <T : OffscreenRenderingContext, O : Any> getContext(contextId: RenderingContextId<T, O>, options: O? = definedExternally): T?(source)
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).