Csharp 有没有办法在避免浮点数学的同时有效地将 16 位 colored颜色 转换为 24 位 colored颜色

不仅可以避免浮点转换，还可以避免乘法和除法.从implementation年款开始:

internal struct Color16Rgb555
{
    private const ushort redMask = 0b01111100_00000000;
    private const ushort greenMask = 0b00000011_11100000;
    private const ushort blueMask = 0b00011111;

    private ushort _value;

    internal Color16Rgb555(ushort value) => _value = value;

    internal byte R => (byte)(((_value & redMask) >> 7) | ((_value & redMask) >> 12));
    internal byte G => (byte)(((_value & greenMask) >> 2) | ((_value & greenMask) >> 7));
    internal byte B => (byte)(((_value & blueMask) << 3) | ((_value & blueMask) >> 2));
}

用法:

var color = new Color16Rgb555(BitConverter.ToUInt16(data, 54 + i));
byte blue  = color.B;
byte green = color.G;
byte red   = color.R;

它为31生成255，因为它用实际5位值的3个MSB位填充其余3位.

但是假设您的data是字节数组，如果您使用我的drawing libraries，则有一个更方便的选项:

// to interpret your data array as 16BPP pixels with RGB555 format:
var my16bppBitmap = BitmapDataFactory.CreateBitmapData(
    data, // your back buffer
    new Size(pixelWidth, pixelHeight), // size in pixels
    stride, // the size of one row in bytes
    KnownPixelFormat.Format16bppRgb555);

// now you can get/set pixels normally    
Color somePixel = my16bppBitmap.GetPixel(0, 0);

// For better performance obtain a row first.
var row = my16bppBitmap[0]; // or FirstRow (+MoveNextRow if you wish)
Color32 asColor32 = row[0]; // accessing pixels regardless of PixelFormat
ushort asUInt16 = row.ReadRaw<ushort>(0); // if you know that it's a 16bpp format