【C#】RGB,CMYK,HSB各類顏色表示的轉換（轉）

【C#】RGB,CMYK,HSB各類顏色表示的轉換

 

1、表示顏色的方式有不少種，如RGB，CMYK，HSB，Hex等等

　　一、RGB：這種表示顏色由三原色構成，經過紅，綠，藍三種顏色份量的不一樣，組合成不一樣的顏色，例如，100%紅+100%綠混合能夠獲得黃色，紅綠藍三種顏色疊加能夠獲得白色，基本上屏幕顯示色彩都採用這種方式

　　二、CMYK：也稱做印刷色彩模式，是一種依靠反光的色彩模式，主要用於印刷，和RGB相似，CMY是3種印刷油墨名稱的首字母：青色Cyan、品紅色Magenta、黃色Yellow。而K取的是black最後一個字母，之因此不取首字母，是爲了不與藍色(Blue)混淆。從理論上來講，只須要CMY三種油墨就足夠了，它們三個加在一塊兒就應該獲得黑色。可是因爲目前製造工藝還不能造出高純度的油墨，CMY相加的結果實際是一種暗紅色。

 

　　三、HSB：經過色相（hues），飽和度（saturation），亮度（brightness）來表示顏色

 

 

2、下面說說關於各類顏色之間的轉換

　　一、RGB與CMYK之間的轉換

        public static void RGB2CMYK(int red, int green, int blue, out double c, out double m, out double y, out double k)
        {
            c = (double)(255 - red) / 255;
            m = (double)(255 - green) / 255;
            y = (double)(255 - blue) / 255;

            k = (double)Math.Min(c, Math.Min(m, y));
            if (k == 1.0)
            {
                c = m = y = 0;
            }
            else
            {
                c = (c - k) / (1 - k);
                m = (m - k) / (1 - k);
                y = (y - k) / (1 - k);
            }
        }
        public static void CMYK2RGB(double c, double m, double y, double k, out int r, out int g, out int b)
        {
            r = Convert.ToInt32((1.0 - c) * (1.0 - k) * 255.0);
            g = Convert.ToInt32((1.0 - m) * (1.0 - k) * 255.0);
            b = Convert.ToInt32((1.0 - y) * (1.0 - k) * 255.0);
        }

　　二、RGB與HSB之間的轉換

        public static void RGB2HSB(int red, int green, int blue, out double hue, out double sat, out double bri)
        {
            double r = ((double)red / 255.0);
            double g = ((double)green / 255.0);
            double b = ((double)blue / 255.0);

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

            hue = 0.0;
            if (max == r && g >= b)
            {
                if (max - min == 0) hue = 0.0;
                else hue = 60 * (g - b) / (max - min);
            }
            else if (max == r && g < b)
            {
                hue = 60 * (g - b) / (max - min) + 360;
            }
            else if (max == g)
            {
                hue = 60 * (b - r) / (max - min) + 120;
            }
            else if (max == b)
            {
                hue = 60 * (r - g) / (max - min) + 240;
            }

            sat = (max == 0) ? 0.0 : (1.0 - ((double)min / (double)max));
            bri = max;
        }
        public static void HSB2RGB(double hue, double sat, double bri, out int red, out int green ,out int blue)
        {
            double r = 0;
            double g = 0;
            double b = 0;

            if (sat == 0)
            {
                r = g = b = bri;
            }
            else
            {
                // the color wheel consists of 6 sectors. Figure out which sector you're in.
                double sectorPos = hue / 60.0;
                int sectorNumber = (int)(Math.Floor(sectorPos));
                // get the fractional part of the sector
                double fractionalSector = sectorPos - sectorNumber;

                // calculate values for the three axes of the color. 
                double p = bri * (1.0 - sat);
                double q = bri * (1.0 - (sat * fractionalSector));
                double t = bri * (1.0 - (sat * (1 - fractionalSector)));

                // assign the fractional colors to r, g, and b based on the sector the angle is in.
                switch (sectorNumber)
                {
                    case 0:
                        r = bri;
                        g = t;
                        b = p;
                        break;
                    case 1:
                        r = q;
                        g = bri;
                        b = p;
                        break;
                    case 2:
                        r = p;
                        g = bri;
                        b = t;
                        break;
                    case 3:
                        r = p;
                        g = q;
                        b = bri;
                        break;
                    case 4:
                        r = t;
                        g = p;
                        b = bri;
                        break;
                    case 5:
                        r = bri;
                        g = p;
                        b = q;
                        break;
                }
            }
            red = Convert.ToInt32(r * 255);
            green = Convert.ToInt32(g * 255);
            blue = Convert.ToInt32(b * 255); ;
        }

　　三、RGB與十六進制Hex表示的轉換

        public static string RGB2Hex(int r, int g, int b)
        {
            return String.Format("#{0:x2}{1:x2}{2:x2}", (int)r, (int)g, (int)b);
        }
        public static Color Hex2Color(string hexColor)
        {
            string r, g, b;

            if (hexColor != String.Empty)
            {
                hexColor = hexColor.Trim();
                if (hexColor[0] == '#') hexColor = hexColor.Substring(1, hexColor.Length - 1);

                r = hexColor.Substring(0, 2);
                g = hexColor.Substring(2, 2);
                b = hexColor.Substring(4, 2);

                r = Convert.ToString(16 * GetIntFromHex(r.Substring(0, 1)) + GetIntFromHex(r.Substring(1, 1)));
                g = Convert.ToString(16 * GetIntFromHex(g.Substring(0, 1)) + GetIntFromHex(g.Substring(1, 1)));
                b = Convert.ToString(16 * GetIntFromHex(b.Substring(0, 1)) + GetIntFromHex(b.Substring(1, 1)));

                return Color.FromArgb(Convert.ToInt32(r), Convert.ToInt32(g), Convert.ToInt32(b));
            }

            return Color.Empty;
        }
        private static int GetIntFromHex(string strHex)
        {
            switch (strHex)
            {
                case ("A"):
                    {
                        return 10;
                    }
                case ("B"):
                    {
                        return 11;
                    }
                case ("C"):
                    {
                        return 12;
                    }
                case ("D"):
                    {
                        return 13;
                    }
                case ("E"):
                    {
                        return 14;
                    }
                case ("F"):
                    {
                        return 15;
                    }
                default:
                    {
                        return int.Parse(strHex);
                    }
            }
        }

 

轉換算法摘自：http://www.codeproject.com/Articles/19045/Manipulating-colors-in-NET-Part-1