static IIntegralImage iiPadCenter(IIntegralImage etc inner, int w, int h) {
  int diffX = w-inner.getWidth();
  int diffY = h-inner.getHeight();
  int left = diffX/2;
  int top = diffY/2;
  ret iiPad(inner, left, top, diffX-left, diffY-top);
}