OffscreenCanvas: contextrestored event

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The contextrestored event of the OffscreenCanvas interface is fired if the browser restores an 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 addEventListener():

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

Alternatively, assign to the event handler property of the interface:

oncontextrestored = (event) => { }

Event type

A generic Event.

Examples

The code fragment below detects the context restored event.

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

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