static Image2B resizeImage2B(int w, int h default widthToHeight(w, img), Image2B img) {
  if (img == null) null;
  int w1 = img.getWidth(), h1 = img.getHeight();
  if (w == w1 && h == h1) ret img;
  byte[] pixels2 = img.pixels, pixels2 = new[(w*h+7)/8];
  int i = 0;
  double x1 = 0, y1 = 0, s;
  for y to h: {
    int i1 = i
    for x to w: {
      if (!region.contains(x1+x, y1+y))
          pixels[i/8] |= 1 << (i & 7);
     ++;
  }
  ret new Image2B(w, h, pixels2);
}