getImage(pixelRatio) {
    if (!this.image_) {
      this.initializeImage_();
    }
    this.replaceColor_(pixelRatio);
    return this.canvas_[pixelRatio] ? this.canvas_[pixelRatio] : this.image_;
  }
@param {number} pixelRatio Pixel ratio.
@return {HTMLImageElement|HTMLCanvasElement|ImageBitmap} Image or Canvas element or image bitmap.