static BWImage subtitle(BWImage img, S text) {
  BWImage img2 = utfToImage(text);
  int w = max(img.getWidth(), img2.getWidth()), h = img.getHeight() + img2.getHeight();
  BWImage img3 = new BWImage(w, h, 1f);
  copyBWImage(img, 0, 0, img3, (w-img.getWidth())/2, 0);
  copyBWImage(img2, 0, 0, img3, (w-img2.getWidth())/2, img.getHeight());
  ret img3;
}