The contextrestored event of the Canvas API is fired if the user agent restores the backing storage for a CanvasRenderingContext2D.

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

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

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

oncontextrestored = (event) => {};

A generic Event.

The code fragment below detects the context restored event.

const canvas = document.getElementById("canvas");

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

• HTMLCanvasElement: contextlost event
• CanvasRenderingContext2D.isContextLost()