OffscreenCanvas: contextrestored event

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

The contextrestored event of the OffscreenCanvas interface is fired if the browser restores a OffscreenCanvasRenderingContext2D context that was previously lost.

You can redraw, re-retrieve resources, and reinitialize the state of your context after receiving this event.

Syntax

Use the event name in methods like addEventListener(), or set an event handler property.

js
addEventListener("contextrestored", (event) => {});

oncontextrestored = (event) => {};

Event type

A generic Event.

Examples

The code fragment below detects the context restored event.

js
const canvas = new OffscreenCanvas(256, 256);
const gl = offscreen.getContext("2d");

canvas.addEventListener(
  "contextrestored",
  (e) => {
    console.log(e);
    // call to redrawCanvas() or similar
  },
  false,
);

Specifications

Specification
HTML Standard
# event-contextrestored
HTML Standard
# handler-offscreencanvas-oncontextrestored

Browser compatibility

BCD tables only load in the browser

See also