// interprets colros in normal scan line fashion
static IntegralImage integralImageFromColors(int w, int h, Color... colors) {
  RGBImage img = new(w, h);
  int i = 0;
  for y to h:
    for x to w:
      img.set(x, y, colors[i++]);
  ret IntegralImage(img);
}

static IntegralImage integralImageFromColors(int w, int h, L<Color> colors) {
  ret integralImageFromColors(w, h, toArray Color(colors));
}