// f: voidfunc(float)
static JSlider liveSliderZeroToX(final float maxValue, final float def, fO f) {
  ret swing(func -> JSlider {
    final int max = 10000;
    final float factor = max/maxValue;
    final JSlider slider = new JSlider(0, max, iround(def*factor));
    slider.addChangeListener(new ChangeListener {
      int lastValue = slider.getValue();
      public void stateChanged(ChangeEvent e) {
        int value = slider.getValue();
        if (value != lastValue) {
          lastValue = value;
          float x = value/factor;
          setToolTip(slider, str(x));
          pcallF(f, x);
        }
      }
    });
    ret slider;
  });
}

Began life as a copy of #1005725