Little RGB to HSL converter I wrote just to see how hard it would be.

rgb-to-hsl.go

package main

import (
    "flag"
    "fmt"
    "math"
    "strconv"
    "strings"
)

func main() {
    flag.Parse()
    input := strings.Split(flag.Arg(0), ",")

    var iR, lowR, iG, lowG, iB, lowB float64

    iR, _ = strconv.ParseFloat(input[0], 8)
    iG, _ = strconv.ParseFloat(input[1], 8)
    iB, _ = strconv.ParseFloat(input[2], 8)

    lowR = iR / 255
    lowG = iG / 255
    lowB = iB / 255

    min := math.Min(math.Min(lowR, lowG), lowB)
    max := math.Max(math.Max(lowR, lowG), lowB)

    var H, S, L float64
    L = (min + max) / 2
    if min == max {
        H = 0
        S = 0
    } else {
        maxSubMin := max - min
        if L < 0.5 {
            S = maxSubMin / (max + min)
        } else {
            S = maxSubMin / (2.0 - max - min)
        }

        if max == lowR {
            H = (lowG - lowB) / maxSubMin
        } else if max == lowG {
            H = 2.0 + (lowB-lowR)/maxSubMin
        } else {
            H = 4.0 + (lowR-lowG)/maxSubMin
        }

        H *= 60
    }

    fmt.Printf("%.0f,%.1f,%.1f\n", math.Round(H), math.Round(S*1000)/10, math.Round(L*1000)/10)
}