Question

我正在创建一种名为DIF（字典图像格式）的图像格式，其中图像指定图像中的调色板（字典），或者可以选择加载外部调色板。

我正在尝试为RGB光谱中的所有可能值创建颜色字典。我已经找到了如何遍历RGB频谱，但是如何遍历所有可能的字典键却不知所措。

每个字典键将由一串大小写字母（如aAaAB）组成，长度为五个字母。这提供了380204032种可能的组合，足以编码RGB中的1670万种颜色。

这将如何工作，以及如何将其与我现有的RGB代码集成，如下所示：

Dictionary<string,Color> rgb = new Dictionary<string,Color>();

for(int r = 0; r <= 255; r++)
{
   for(int g = 0; g <= 255; g++)
   {
        for(int b = 0; b <= 255; b++)
        {
            //Add colors to dictionary here
        }
   }
}

Answer 1

我建议你根本不需要字典。

相反，您可以根据需要将每种颜色转换为基本52（a-zA-Z）表示法。

这是一个例子。它使用了一些基本转换代码：Quickest way to convert a base 10 number to any base in .NET?

using System;
using System.Drawing;

namespace Demo
{
    internal class Program
    {
        private void run()
        {
            // As an example, iterate through all known colours and demonstrate
            // that we can convert each colour to a 5 character string and back.

            var colors = Enum.GetValues(typeof(KnownColor));

            foreach (KnownColor knowColor in colors)
            {
                Color colour = Color.FromKnownColor(knowColor);
                string colourString = ColourToBase52(colour);
                Color decodedColour = ColourFromBase52(colourString);

                if (colour.ToArgb() != decodedColour.ToArgb())
                    Console.WriteLine("ERROR with colour " + colour); // Expect this to complain about TRANSPARENT.
                else
                    Console.WriteLine("{0,-30} is represented by {1}", colour, colourString);
            }
        }

        public static string ColourToBase52(Color colour)
        {
            int value = colour.ToArgb() & 0x00FFFFFF; // Mask off the alpha channel.
            return ToBase52(value);
        }

        public static Color ColourFromBase52(string colour)
        {
            int value = FromBase52(colour);
            return Color.FromArgb(unchecked((int)(0xFF000000 | value)));
        }

        public static string ToBase52(int value)
        {
            char[] baseChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();
            int targetBase = baseChars.Length;

            int i = 32;
            char[] buffer = new char[i];

            do
            {
                buffer[--i] = baseChars[value % targetBase];
                value = value / targetBase;
            }
            while (value > 0);

            char[] result = new char[32 - i];
            Array.Copy(buffer, i, result, 0, 32 - i);

            return new string(result).PadLeft(5, 'a');
        }

        public static int FromBase52(string value)
        {
            char[] baseChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();
            int targetbase = baseChars.Length;

            int multiplier = 1;
            int result = 0;

            for (int i = value.Length-1; i >= 0; --i)
            {
                int digit = Array.IndexOf(baseChars, value[i]);
                result += digit*multiplier;
                multiplier *= targetbase;
            }

            return result;
        }

        public static void Main()
        {
            new Program().run();
        }
    }
}

C＃通过5个字母的可能组合迭代

1 个答案: