Measure population with a tolerance

[sydney-d]

Hello,

I'd like to get the population of the different swatches but with a tolerance, for example : population of the vibrant swatch +/- 10% on H, S, and L.

I understand that at this point, I have all the image's colors with their populations: https://github.com/marijnvdwerf/material-palette-php/blob/master/src/PaletteGenerator.php#L46

But then I don't understand what's going on witht the VBox class, what does it do ?

Any hint on how to achieve this ?

Thanks