/// <summary>
        /// 指定したHslColorからColorを作成する
        /// </summary>
        /// <param name="hsl">HslColor</param>
        /// <returns>Color</returns>
        public static Color ToRgb(HslColor hsl)
        {
            float s = hsl.S;
            float l = hsl.L;

            float r1, g1, b1;

            if (s == 0)
            {
                r1 = l;
                g1 = l;
                b1 = l;
            }
            else
            {
                float h = hsl.H / 60f;
                int   i = (int)Math.Floor(h);
                float f = h - i;
                //float c = (1f - Math.Abs(2f * l - 1f)) * s;
                float c;
                if (l < 0.5f)
                {
                    c = 2f * s * l;
                }
                else
                {
                    c = 2f * s * (1f - l);
                }
                float m = l - c / 2f;
                float p = c + m;
                //float x = c * (1f - Math.Abs(h % 2f - 1f));
                float q;                 // q = x + m
                if (i % 2 == 0)
                {
                    q = l + c * (f - 0.5f);
                }
                else
                {
                    q = l - c * (f - 0.5f);
                }

                switch (i)
                {
                case 0:
                    r1 = p;
                    g1 = q;
                    b1 = m;
                    break;

                case 1:
                    r1 = q;
                    g1 = p;
                    b1 = m;
                    break;

                case 2:
                    r1 = m;
                    g1 = p;
                    b1 = q;
                    break;

                case 3:
                    r1 = m;
                    g1 = q;
                    b1 = p;
                    break;

                case 4:
                    r1 = q;
                    g1 = m;
                    b1 = p;
                    break;

                case 5:
                    r1 = p;
                    g1 = m;
                    b1 = q;
                    break;

                default:
                    throw new ArgumentException("色相の値が不正です。", "hsl");
                }
            }

            return(Color.FromArgb(
                       (int)Math.Round(r1 * 255f),
                       (int)Math.Round(g1 * 255f),
                       (int)Math.Round(b1 * 255f)));
        }