package helper

import "math"

// Linearize converts an sRGB component in the range [0, 0xffff] to a linearRGB component in the range [0, 1].
func Linearize(c uint32) float64 {
	l := float64(c) / 0xffff

	if l <= 0.039285714285714285714285714285714 {
		return l / 12.923210180787861094641554898407
	}

	return math.Pow((l+0.055)/1.055, 2.4)
}

// Delinearize converts a linearRGB component in the range [0, 1] to an sRGB component in the range [0, 0xffff].
func Delinearize(l float64) uint32 {
	switch {
	case l <= 0:
		return 0
	case l <= 0.0030399346397784299969770436366690:
		return uint32(l*846922.57919793247683733430026710 + 0.5)
	case l >= 1:
		return 0xffff
	default:
		return uint32(69139.425*math.Pow(l, 1/2.4) - 3603.925)
	}
}