public static Task <int> DebugDump(FileInfo source, string output, CancellationToken cancellationToken)
{
if (source is null || source.Length == 0)
{
Console.WriteLine("Input file are not specified.");
return(Task.FromResult(1));
}
if (string.IsNullOrEmpty(output))
{
output = source.FullName;
}
byte[] input = File.ReadAllBytes(source.FullName);
var decoder = new JpegDecoder();
decoder.SetInput(input);
decoder.Identify();
int numberOfComponents = decoder.NumberOfComponents;
if (numberOfComponents > 4)
{
throw new NotSupportedException("Number of components greater than 4 is not supported.");
}
ushort[] buffer = new ushort[decoder.Width * decoder.Height * 4];
var outputWriter = new JpegExtendingOutputWriter(decoder.Width, decoder.Height, 4, decoder.Precision, buffer);
decoder.SetOutputWriter(outputWriter);
decoder.Decode();
// We use RGBA PNG image to store 4 components.
// Its content may be Grayscale, YCbCr or others.
Rgba32[] pixels = new Rgba32[decoder.Width * decoder.Height];
Array.Fill(pixels, new Rgba32(255, 255, 255, 255));
using var image = Image.WrapMemory(pixels.AsMemory(), decoder.Width, decoder.Height);
// high bits
CopyHighBits(buffer, pixels, numberOfComponents);
image.Save(output + ".high.png");
// apply prediction
ApplyPrediction(buffer);
// low bits
CopyLowBits(buffer, pixels, numberOfComponents);
image.Save(output + ".low-diff.png");
return(Task.FromResult(0));
}