.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 and .NET 10 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);
}
}
}