sclass JTargetAndActualSlider extends MetaWithChangeListeners is Swingable {
  new TargetAndActual<Double> data;
  settableWithVar bool sliderEnabled = true;
  settableWithVar double min;
  settableWithVar double max = 100;
  settableWithVar int decimalsToShow = 1;
  settableWithVar int widthOfNumbers = 50;

  transient JColorBar bar;
  transient JSlider slider;
  transient JLabel lblActual, lblTarget;
  
  *() {}
  *(TargetAndActual<Double> *data) {}
  
  double value() { ret unnull(data.value()); }
  double target() { ret unnull(data.target()); }

  cachedVisualize {
    bar = swing(-> new JColorBar().max(max));
    slider = jLiveValueSlider_double_bothWays(min, max, data.varTarget());
    lblActual = jlabel();
    lblTarget = jlabel();
    data.varActual().onChangeAndNow(-> {
      bar.setValue(value());
      lblActual?.setText(renderValue(value());
    });
    data.varTarget().onChangeAndNow(->
      slider.setValue(target());
      lblTarget.setValue(target());
    });
      
    varSliderEnabled().onChangeAndNow(-> setEnabled(slider, sliderEnabled));
    
    ret vstackWithSpacing(
      centerAndEastWithMargin(bar, jMinWidth(widthOfNumbers, lblActual)),
      centerAndEastWithMargin(slider, jMinWidth(widthOfNumbers, lblTarget)));
  }
  
  swappable S renderValue(double value) {
    ret formatDoubleX(value, decimalsToShow);
  }
}