static float showFrequencyImage2_maxValue = 0.3f;

static ImageSurface showFrequencyImage2(File audioFile) {
  if (audioFile == null) null;
  ret showFrequencyImage2(audioFile.getName(), audioFileToFrequencyImage(audioFile));
}
  
static ImageSurface showFrequencyImage2(S name, final BWImage img) {
  ImageSurface is = showZoomedBWImage(name, img);
  final ImageSurface is2 = jImageSurface();
  is2.setZoom(2);
  final SimpleLiveValue<Float> lvThreshold = floatLiveValue(0.1f);
  
  Runnable update = runAndReturn(r {
    is2.setImage(bwImage_markColumnsWhite(img.getWidth(), 10, printStruct("change points: ", audio_changePoints1(img, lvThreshold!))));
  });
  
  lvThreshold.onChange(update);
  addToWindowAndPack(is, vstack(is2, jLiveValueSliderZeroToX(showFrequencyImage2_maxValue, lvThreshold)));
  ret is;
}

Began life as a copy of #1018613