@Override
 public double getPoint(double value) {
   return HistogramData.getPointFromRGBData(
       value, HistogramData.SEQUENTIAL_ORRD, RGBChannel.GREEN);
 }
 @Override
 public double getPoint(double value) {
   return HistogramData.getPointFromRGBData(value, HistogramData.NIPY_SPECTRAL, RGBChannel.GREEN);
 }
 @Override
 public double getPoint(double value) {
   return HistogramData.getPointFromRGBData(value, HistogramData.DIVERGENT_RYG, RGBChannel.RED);
 }