c# - 从一个字节中获取值

Question

如果我有一个方法接收一个红色字节、一个绿色字节和一个蓝色字节，并且我知道如果我从每个字节中提取红色字节中的最后 3 位，则提取红色字节中的最后 2 位绿色字节和蓝色字节的最后 3 位，我将如何完成这个？我正在使用下面的代码，但它并不完全有效。我在这里做错了什么？

    private const byte InverseBlueMask = 7; // 00000111
    private const byte InverseGreenMask = 3; // 00000011
    private const byte InverseRedMask = 7; //  00000111

    //private const byte InverseBValueMask = 31; // 00011111
    //private const byte InverseGValueMask = 231; // 11100111
    //private const byte InverseRValueMask = 248; //  11111000



  public void getEachBitOfMessage(byte byteToManipulate, int colour)
    {
        byte value = 0;
        byte returnByte = 0; 


        if (colour == BLUE)
        {
            value = (byte)(byteToManipulate | BValueMask);
            value = (byte)(value >> 5);
            returnByte = (byte)(byteToManipulate | InverseBlueMask);
            returnByte = (byte)(returnByte & value);
            String theByte = returnByte.ToString(); 

        }
        else if (colour == GREEN)
        {
            value = (byte)(byteToManipulate | GValueMask);
            value = (byte)(value >> 3);
            returnByte = (byte)(byteToManipulate | InverseGreenMask);
            returnByte = (byte)(returnByte & value);
            String theByte = returnByte.ToString(); 

        }
        else if (colour == RED)
        {
            value = (byte)(byteToManipulate | RValueMask);
            returnByte = (byte)(byteToManipulate | InverseRedMask);
            returnByte = (byte)(returnByte & value);
            String theByte = returnByte.ToString(); 

        }
     }

这是我用来将信息位放入每个颜色字节的方法。

    private const byte BlueMask = 248; // 11111000
    private const byte GreenMask = 252; // 11111100
    private const byte RedMask = 248; //  11111000
    private const byte BValueMask = 224; // 11100000
    private const byte GValueMask = 24; // 00011000
    private const byte RValueMask = 7; //  00000111



     public byte changeEachBit(byte byteToManipulate, int colour, byte theMessage)
     {

        byte value = 0;
        byte returnByte = 0; 

        if (colour == BLUE)
        {
           value= (byte)(theMessage & BValueMask);
           value = (byte)(value >> 5); 
           returnByte = (byte)(byteToManipulate & BlueMask);
           returnByte = (byte)(returnByte | value); 

        }
        else if (colour == GREEN)
        {
            value = (byte)(theMessage & GValueMask);
            value = (byte)(value >> 3);
            returnByte = (byte)(byteToManipulate & GreenMask);
            returnByte = (byte)(returnByte | value);

        }
        else if (colour == RED)
        {
            value = (byte)(theMessage & RValueMask);
            returnByte = (byte)(byteToManipulate & RedMask);
            returnByte = (byte)(returnByte | value);

        }
     }

Answer 1

From each byte if i extract the last 3 bits in the red byte, last 2 bits in the green byte and the last 3 bits in the blue byte, how would i accomplish this?

这将屏蔽除您要求的低 n 位之外的所有内容。

red &= 0x07;
green &= 0x03;
blue &= 0x07;