HsvFromRgb method

gistfile1.cs

        private HSV HsvFromRgb(double r, double g, double b)
        {
            var max = Math.Max(Math.Max(r, g), b);
            var min = Math.Min(Math.Min(r, g), b);
            var sub = max - min;

            double h = 0, s = 0, v = 0;

            // Calculate Hue
            if (sub == 0)
            {
                // MAX = MIN(例・S = 0)のとき、 Hは定義されない。
                h = 0;
            }
            else 
            {
                if(max == r) 
                {
                    h = (60 * (g - b) / sub);
                } 
                else if(max == g) 
                {
                    h = (60 * (b - r) / sub) + 120;
                } 
                else if(max == b) 
                {
                    h = (60 * (r - g) / sub) + 240;
                }

                // さらに H += 360 if H < 0
                if (h < 0)
                {
                    h += 360;
                }
            }

            // Calculate Saturation
            if (max > 0)
            {
　　　　　　  s = sub / max;
            }

            // Calculate Value
            v = max;

            return new HSV(h, s, v);
        }