module Term::ANSIColor::RGBColorMetrics::CompuPhase

def self.distance(rgb1, rgb2)
  rmean = (rgb1.red + rgb2.red) / 2
  rgb1.weighted_euclidean_distance_to rgb2,
      [ 2 + (rmean >> 8), 4, 2 + ((255 - rmean) >> 8) ]
end