How to access density values from HeatmapLayer for legend creation

[akiyatomohiro]

Hello! I'm trying to create a legend for a heatmap visualization. I need to get the density values calculated by the HeatmapLayer to properly map colors in my legend.

Currently, I'm using HeatmapLayer like this:

export const heatmapLayer = <T>(
  props: HeatmapLayerProps<T>
): HeatmapLayer<T> => {
  props = {
    ...defaultProps,
    ...props,
  };
  return new HeatmapLayer(props);
};

// Usage:
heatmapLayer({
  id: 'hoge',
  data: foo,
  colorRange: bar,
  getPosition: (d) => [d.start_lon, d.start_lat],
})

I'm looking to access either:
Raw density values before normalization, or
Normalized density values (0-1 range)
For instance, with point density values like [1, 5, 10, 15, 20], I'd need either:
These raw values, or
Their normalized form: [0, 0.21, 0.47, 0.74, 1]
Is there a way to access these values from the HeatmapLayer to create an accurate legend