srecord noeq RawBufferedImageDistance_sameSize(BufferedImage img1,

  BufferedImage img2) {

  settable long stoppingValue = Int.MAX_VALUE;

  int w, h;

  int x, y; // where we stopped calculating

  long sum;

  bool completed() { ret w != 0 && x == w && y == h; }

  long get() {

    int w = this.w = img1.getWidth(), h = this.h = img1.getHeight();

    assertSameSize(img1, img2);

    var gp1 = grabbableIntPixels_fastOrSlow(img1);

    var gp2 = grabbableIntPixels_fastOrSlow(img2);

    int iPixels1 = gp1.offset, iPixels2 = gp2.offset;

    int[] pixels1 = gp1.data, pixels2 = gp2.data;

    long sum = 0;

    for y to h: {

      for x to w: {

        sum += rawRGBDiff(

          pixels1[iPixels1+x],

          pixels2[iPixels2+x]);

        // cancel if difference out of interest range

        if (sum > stoppingValue) {

          this.x = x; this.y = y;

          this.sum = sum;

          ret sum;

        }

      }

      iPixels1 += gp1.scanlineStride;

      iPixels2 += gp2.scanlineStride;

    }

    this.x = w; this.y = h;

    ret this.sum = sum;

  }

}