Convert RGB color (0-255) to HSL (h: 0-360; s, l: 0-1)

gistfile1.cs

private Tuple<double, double, double> RgbToHsl(Tuple<int, int, int> rgb)
{
    int r = rgb.Item1;
    int g = rgb.Item2;
    int b = rgb.Item3;
    double h, s, l;

    int max = Math.Max(r, Math.Max(g, b));
    int min = Math.Min(r, Math.Min(g, b));

    // set h
    if (max == min)
    {
        h = 0;
    }
    else if (max == r && g >= b)
    {
        h = 60.0 * (g - b) / (max - min);
    }
    else if (max == r && g < b)
    {
        h = 60.0 * (g - b) / (max - min) + 360;
    }
    else if (max == g)
    {
        h = 60.0 * (b - r) / (max - min) + 120;
    }
    else
    {
        h = 60.0 * (r - g) / (max - min) + 240;
    }

    // set l
    l = (max + min) * 0.5 / 255;

    // set s
    if (max + min == 0 || max == min)
    {
        s = 0;
    }
    else if (l <= 0.5)
    {
        s = Convert.ToDouble(max - min) / (max + min);
    }
    else
    {
        s = Convert.ToDouble(max - min) / (2 * 255 - (max + min));
    }

    return Tuple.Create<double, double, double>(h, s, l);
}