// The core integral 1D image.
srecord IIColumnToAudioSample(IIntegralImage img, double x1, double x2) implements IAudioSample {

  public int channels() { ret 1; }
  public double sampleRate() { ret 1; } // not applicable
  public double h aka length() { ret img.getHeight(); }
  
  public DoubleRange bounds() { ret DoubleRange(0, h()); }
  
  public double sampleSum(int channel, double start, double end) {
    ret img.rectSum(x1, start, x2, end, channel);
  }
}