// resulting image is of size (img.w()-blurw, img.h()-blurh)

meta-for IntegralImage also as IIntegralImage {

  static int[] blurredPixelsFromIntegralImage(int blurw, int blurh default blurw, IntegralImage img) {
    int w1 = img.getWidth(), h1 = img.getHeight();
    int w = w1-blurw, h = h1-blurh;
    if (w < 0 || h < 0) null;
    int[] pixels = new[w*h];
    int i = 0;
    double area = blurw*blurh;
    
    for y to h: {
      for x to w: {
        dbl r = doubleRatio(img.rectSum(x, y, x+blurw, y+blurh, 0), area);
        dbl g = doubleRatio(img.rectSum(x, y, x+blurw, y+blurh, 1), area);
        dbl b = doubleRatio(img.rectSum(x, y, x+blurw, y+blurh, 2), area);
        pixels[i++] = rgbIntFromDoubles_fullAlpha(r, g, b);
      }
    }
    
    ret pixels;
  }

}