meta-for BWIntegralImage also as IBWIntegralImage {

  static BufferedImage scaledGrayImageFromBWIntegralImage(int w, BWIntegralImage img) {
    ret scaledGrayImageFromBWIntegralImage(img, w);
  }
  
  static BufferedImage scaledGrayImageFromBWIntegralImage(BWIntegralImage img, int w, int h default heightForWidth(img, w)) {
    int w1 = img.w, h1 = img.h;
    double stepX = w1/w, stepY = h1/h;
    byte[] pixels = new[w*h];
    int i = 0;
    double srcY = 0;
    
    for y to h: {
      double srcX = 0, nextSrcY = srcY+stepY;
      
      for x to w: {
        double nextSrcX = srcX+stepX;
        int pixel = iround(img.getPixelAverage(srcX, srcY, nextSrcX, nextSrcY));
        pixels[i++] = clampToUByte(pixel);
        srcX = nextSrcX;
      }
      srcY = nextSrcY;
    }
    
    ret newGrayBufferedImage(w, h, pixels);
  }

}