offscreen-canvas-polyfill.js

offscreen-canvas-polyfill.js

if (!window.OffscreenCanvas) {
  window.OffscreenCanvas = class OffscreenCanvas {
    constructor(width, height) {
      this.canvas = document.createElement('canvas');
      this.canvas.width = width;
      this.canvas.height = height;

      this.canvas.transferToImageBitmap = () => {
        const ctx = this.canvas.getContext('2d');
        if (!ctx) return;
        return ctx.getImageData(0, 0, this.canvas.width, this.canvas.height);
      };

      this.canvas.convertToBlob = () => {
        return new Promise((resolve) => {
          this.canvas.toBlob(resolve);
        });
      };

      return this.canvas;
    }
  };
}