set flag LeanMode.

set flag l_withoutReflection.

set flag fail_dontUseFailClass.

set flag iround_noGeneric.

set flag Reparse.

final sclass IntegralImage {

  final int w, h;

  final int[] data; // 3 ints per pixel

  /* *(BufferedImage img) {

    w = img.getWidth();

    h = img.getHeight();

    if (longMul(w, h) > 8000000) fail("Image too big: " + w + "*" + h);

    int[] pixels = pixelsOfBufferedImage(img);

  */

  *(int *w, int *h, int[] pixels) {

    data = new int[w*h*3];

    int i = 0, j = 0, sumR = 0, sumG = 0, sumB = 0;

    for x to w: {

      int rgb = pixels[j++];

      data[i++] = (sumR += (rgb >> 16) & 0xFF);

      data[i++] = (sumG += (rgb >> 8) & 0xFF);

      data[i++] = (sumB += rgb & 0xFF);

    }

    for (int y = 1; y < h; y++) {

      sumR = sumG = sumB = 0;

      for x to w: {

        int rgb = pixels[j++];

        sumR += (rgb >> 16) & 0xFF;

        sumG += (rgb >> 8) & 0xFF;

        sumB += rgb & 0xFF;

        data[i] = sumR + data[i-w*3];

        data[i+1] = sumG + data[i-w*3+1];

        data[i+2] = sumB + data[i-w*3+2];

        i += 3;

      }

    }

  }

  // gets the integral value at x/y for given RGB channel

  public double getIntegralValue(int x, int y, int channel) {

    ret x < 0 || y < 0 || x >= w || y >= h ? 0

      : data[(y*w+x)*3+channel];

  }

  // gets sum of the 3 channels

  public double getIntegralValue(int x, int y) {

    if (x < 0 || y < 0 || x >= w || y >= h) ret 0;

    int i = (y*w+x)*3;

    ret data[i]+data[i+1]+data[i+2];

  }

  double averageBrightness() {

    ret doubleRatio(getIntegralValue(w-1, h-1), w*h*3*255.0);

  }

  toString {

    ret "IntegralImage " + w + "*" + h + ", brightness: " + this.averageBrightness();

  }

  //public BufferedImage getBufferedImage() { ret integralImageToBufferedImage(this); }

  public int getWidth() { ret w; }

  public int getHeight() { ret h; }

  double rectSum(int x1, int y1, int x2, int y2, int channel) {

    double bottomLeft  = getIntegralValue(x1-1, y2-1, channel);

    double bottomRight = getIntegralValue(x2-1, y2-1, channel);

    double topLeft     = getIntegralValue(x1-1, y1-1, channel);

    double topRight    = getIntegralValue(x2-1, y1-1, channel);

    ret bottomRight+topLeft-topRight-bottomLeft;

  }

  double rectSum(int x1, int y1, int x2, int y2) {

    double bottomLeft  = getIntegralValue(x1-1, y2-1);

    double bottomRight = getIntegralValue(x2-1, y2-1);

    double topLeft     = getIntegralValue(x1-1, y1-1);

    double topRight    = getIntegralValue(x2-1, y1-1);

    ret bottomRight+topLeft-topRight-bottomLeft;

  }

}