.Net (.NET 8 and .NET 10) compatible managed dithering library implementation in C#
$ dotnet add package LibDitheringCSharp (C#) versions of certain dithering algorithms. This project is .NET 8 compatible, managed and available as Nuget!
Use Atkinson dithering with web safe color reduction for 24 bit PNG input with System.Drawing (this example is Windows only)
public void DoAtkinsonDithering()
{
AtkinsonDitheringRGB<byte> atkinson = new AtkinsonDitheringRGB<byte>(TrueColorBytesToWebSafeColorBytes);
using(FileStream pngStream = new FileStream("half.png", FileMode.Open, FileAccess.Read))
using(var image = new Bitmap(pngStream))
{
byte[,,] bytes = ReadBitmapToColorBytes(image);
TempByteImageFormat temp = new TempByteImageFormat(bytes);
atkinson.DoDithering(temp);
WriteToBitmap(image, temp.GetPixelChannels);
image.Save("test.png");
}
}
private static void TrueColorBytesToWebSafeColorBytes(in byte[] input, ref byte[] output)
{
for (int i = 0; i < input.Length; i++)
{
output[i] = (byte)(Math.Round(input[i] / 51.0) * 51);
}
}
private static byte[,,] ReadBitmapToColorBytes(Bitmap bitmap)
{
byte[,,] returnValue = new byte[bitmap.Width, bitmap.Height, 3];
for (int x = 0; x < bitmap.Width; x++)
{
for (int y = 0; y < bitmap.Height; y++)
{
Color color = bitmap.GetPixel(x, y);
returnValue[x, y, 0] = color.R;
returnValue[x, y, 1] = color.G;
returnValue[x, y, 2] = color.B;
}
}
return returnValue;
}
private static void WriteToBitmap(Bitmap bitmap, Func<int, int, byte[]> reader)
{
for (int x = 0; x < bitmap.Width; x++)
{
for (int y = 0; y < bitmap.Height; y++)
{
byte[] read = reader(x, y);
Color color = Color.FromArgb(read[0], read[1], read[2]);
bitmap.SetPixel(x, y, color);
}
}
}