public DecodedPNGData(IdatChunk idatChunk, IhdrChunk ihdrChunk, PlteChunk plteChunk, string decodedIdat, string unfilteredDatastreamString, string filteredDatastreamString, byte[] unfilteredIdatDatastream, int scanlineLenght)
{
IdatChunk = idatChunk;
IhdrChunk = ihdrChunk;
PlteChunk = plteChunk;
DecodedIdat = decodedIdat;
UnfilteredDatastreamString = unfilteredDatastreamString;
FilteredDatastreamString = filteredDatastreamString;
UnfilteredIdatDatastream = unfilteredIdatDatastream;
ScanlineLenght = scanlineLenght;
}
public async Task CreatePngFile()
{
var header = new IhdrChunk(752, 1334, 8, ColorType.TruecolorAlpha);
var idat = new IdatChunk(header, rawRgbaData, FilterType);
var end = new IendChunk();
var pngFile = new PngFile()
{
header,
idat,
end
};
using (var ms = new MemoryStream())
await pngFile.WriteFileAsync(ms);
}
/// <summary>
/// Attempts to read XX bytes of the stream.
/// </summary>
internal static IdatChunk Read(uint length, byte[] array)
{
var chunk = new IdatChunk
{
Length = length, //Chunk length, 4 bytes.
ChunkType = "IDAT" //Chunk type, 4 bytes.
};
using (var stream = new MemoryStream(array))
{
//Chunk details, XX bytes.
chunk.FrameData = stream.ReadBytes(length); // - 4
}
return(chunk);
}
internal DecodedPNGData DecodeByteArray(byte[] arrayByte)
{
IdatChunk idatChunk = ReadIdatChunk(arrayByte);
PlteChunk plteChunk = ReadPlteChunk(arrayByte);
IhdrChunk ihdrChunk = ReadIhdrChunk(arrayByte);
int scanlineLenght = CalculateScanlineLenght(ihdrChunk);
byte[] unfilteredIdatDatastream = UnfilterImageDatastream(scanlineLenght, idatChunk, ihdrChunk);
string decodedBytes = PrintBytesToString(arrayByte, 8);
string decodedAscii = PrintBytesToAsciiString(arrayByte);
string decodedIdat = PrintBytesToString(idatChunk.DatastreamBytes, scanlineLenght);
string unfilteredDatastreamString = PrintBytesToString(unfilteredIdatDatastream, scanlineLenght - 1);
string filteredDatastreamString = PrintBytesToString(idatChunk.DatastreamBytes, scanlineLenght);
return(new DecodedPNGData(idatChunk, ihdrChunk, plteChunk, decodedIdat, unfilteredDatastreamString, filteredDatastreamString, unfilteredIdatDatastream, scanlineLenght));
}
public async Task Can_write_PNG_file(string imageName, FilterType type, int bitDepth)
{
var asm = typeof(PngFileTests).GetTypeInfo().Assembly;
var resource = asm.GetManifestResourceStream(imageName);
byte[] rawRgbaData;
using (var ms = new MemoryStream()) {
await resource.CopyToAsync(ms);
rawRgbaData = ms.ToArray();
}
var header = new IhdrChunk(752, 1334, bitDepth, ColorType.TruecolorAlpha);
var idat = new IdatChunk(header, rawRgbaData, type);
var end = new IendChunk();
var pngFile = new PngFile()
{
header,
idat,
end
};
var path = Path.Combine(Path.GetDirectoryName(asm.Location), $"Zooey-{bitDepth}-{type}.png");
using (var fs = new FileStream(path, FileMode.Create))
await pngFile.WriteFileAsync(fs);
Assert.True(File.Exists(path));
Assert.Equal(3, pngFile.ChunkCount);
var result = ToolHelper.RunPngCheck(path);
Assert.Equal(0, result.ExitCode);
System.Console.Write(result.StandardOutput);
}
internal ApngFrame GetFrame(int index)
{
//Build each frame using:
//Starting blocks: IHDR, tIME, zTXt, tEXt, iTXt, pHYs, sPLT, (iCCP | sRGB), sBIT, gAMA, cHRM, PLTE, tRNS, hIST, bKGD.
//Image data: IDAT.
//End block: IEND.
var chunks = Chunks.Where(w => w.FrameGroupId == index).ToList();
var otherChunks = Chunks.Where(w => w.FrameGroupId == -1 && w.ChunkType != "IDAT").ToList();
if (!chunks.Any())
{
return(null);
}
var frame = new ApngFrame();
//First frame • Second frame
//Default image is part of the animation: fcTL + IDAT • fcTL + fdAT
//Default image isn't part of the animation: IDAT • fcTL + fdAT
if (chunks[0].ChunkType == "fcTL")
{
var fctl = FctlChunk.Read(chunks[0].Length, chunks[0].ChunkData);
frame.Delay = fctl.DelayNum == 0 ? 10 : (int)(fctl.DelayNum / (fctl.DelayDen == 0 ? 100d : fctl.DelayDen) * 1000d);
frame.Width = fctl.Width;
frame.Height = fctl.Height;
frame.Left = fctl.XOffset;
frame.Top = fctl.YOffset;
frame.ColorType = Ihdr.ColorType;
frame.BitDepth = Ihdr.BitDepth;
frame.DisposeOp = fctl.DisposeOp;
frame.BlendOp = fctl.BlendOp;
using (var stream = new MemoryStream())
{
//Png signature, 8 bytes.
stream.WriteBytes(new byte[] { 137, 80, 78, 71, 13, 10, 26, 10 });
//Image header chunk. 25 bytes.
Ihdr.Write(stream, fctl.Width, fctl.Height);
//Any other auxiliar chunks.
foreach (var other in otherChunks)
{
other.Write(stream);
}
//Frame has multiple chunks.
if (chunks.Count > 2)
{
var datas = new List <byte[]>();
//Data chunks.
for (var i = 1; i < chunks.Count; i++)
{
switch (chunks[i].ChunkType)
{
case "fdAT":
{
var fdat = FdatChunk.Read(chunks[i].Length, chunks[i].ChunkData);
datas.Add(fdat.FrameData);
break;
}
case "IDAT":
{
var idat = IdatChunk.Read(chunks[i].Length, chunks[i].ChunkData);
datas.Add(idat.FrameData);
break;
}
}
}
//Write combined frame data.
var length = datas.Sum(s => s.Length);
stream.WriteUInt32(BitHelper.ConvertEndian((uint)length)); //4 bytes.
stream.WriteBytes(Encoding.ASCII.GetBytes("IDAT")); //4 bytes.
stream.WriteBytes(datas.SelectMany(s => s).ToArray()); //XX bytes.
stream.WriteUInt32(BitHelper.ConvertEndian(CrcHelper.Calculate(stream.PeekBytes(stream.Position - (length + 4), length + 4)))); //CRC, 4 bytes.
}
else
{
switch (chunks[1].ChunkType)
{
case "fdAT":
{
var fdat = FdatChunk.Read(chunks[1].Length, chunks[1].ChunkData);
fdat.Write(stream);
break;
}
case "IDAT":
{
var idat = IdatChunk.Read(chunks[1].Length, chunks[1].ChunkData);
idat.Write(stream);
break;
}
}
}
//End chunk.
stream.WriteUInt32(BitHelper.ConvertEndian(0u)); //Chunk length, 4 bytes.
stream.WriteBytes(Encoding.ASCII.GetBytes("IEND")); //Chunk type, 4 bytes.
stream.WriteUInt32(BitHelper.ConvertEndian(CrcHelper.Calculate(stream.PeekBytes(stream.Position - 4, 4)))); //CRC, 4 bytes.
//Gets the whole Png.
frame.ImageData = stream.ToArray();
}
}
else
{
//This is not supposed to happen.
//All chunks with an FrameGroupId are grouped with a starting fcTL, ending with a IDAT or fdAT chunk.
LogWriter.Log(new Exception("Missing fcTL on frame number " + index), $"It was not possible to read frame number {index}");
return(null);
}
return(frame);
}
private byte[] UnfilterImageDatastream(int scanlineLenght, IdatChunk idatChunk, IhdrChunk ihdrChunk)
{
//int datastreamLenght = chunkIhdr.height * chunkIhdr.width * scanlineLenght;
byte[] datastreamIdat = idatChunk.DatastreamBytes;
int datastreamLenght = datastreamIdat.Length;
// Datastream after unfitering = size - amount of filter bytes
int amountOfScanLines = ihdrChunk.Height;
byte[] refilteredDatastream = new byte[datastreamLenght];
// Lenght of the scanLine without filter byte
int scanLineLenWithoutFilter = scanlineLenght - 1;
// pixel size (in bytes)
int pixelbytesLenght = 4;
E_ColorType colorType = ihdrChunk.ColorType;
if (colorType == E_ColorType.GRAYSCALE)
{
pixelbytesLenght = 1;
}
else if (colorType == E_ColorType.GRAYSCALE_ALPHA)
{
pixelbytesLenght = 2;
}
else if (colorType == E_ColorType.TRUECOLOR)
{
pixelbytesLenght = 3;
}
else if (colorType == E_ColorType.TRUECOLOR_ALPHA)
{
pixelbytesLenght = 4;
}
//Actual used scanLine and unfilteredScanLine
byte[] tempScanline; // Actual filtered scanline
byte[] previousReconScanline; // Previous scanline which was reconstructed;
byte[] unfilteredScanline = new byte[scanlineLenght - 1];
for (int datastreamScanlineIter = 0; datastreamScanlineIter < amountOfScanLines; datastreamScanlineIter++)
{
int datastreamIter = (datastreamScanlineIter * (scanlineLenght));
// Each iteration is on another scanline
tempScanline = CutFromDatastream(datastreamIdat, datastreamIter, scanlineLenght);
//Checking tempScanine FILTER TYPE:
if (tempScanline[0] == 0)
{
// Console.WriteLine("--- Filter method 0: Non ---");
//NOTHING TO DO - FILTER 0
for (int scanLineIter = 1; scanLineIter < tempScanline.Length; scanLineIter++)
{
unfilteredScanline[scanLineIter - 1] = tempScanline[scanLineIter];
}
}
else if (tempScanline[0] == 1)
{
// Console.WriteLine("--- Filter method 1: Sub ---");
//Actual and previous used pixel (in bytes)
byte[] tempPixel = new byte[pixelbytesLenght];
byte[] reconAPixel = new byte[pixelbytesLenght]; // recon(a) - pixel on the left to actual pixel (tempPiexl)
byte[] reconXPixel = new byte[pixelbytesLenght]; // recon(x) - reconstructed actual pixel;
// Pixel on the left from the first pixel in scanline stores 0 values
for (int k = 0; k < pixelbytesLenght; k++)
{
reconAPixel[k] = 0;
}
for (int scanLineIter = 1; scanLineIter < tempScanline.Length; scanLineIter += pixelbytesLenght) // scanLineIter=1 becouse of filter byte
{
//Update pixel data
for (int k = 0; k < pixelbytesLenght; k++)
{
tempPixel[k] = tempScanline[scanLineIter + k];
}
for (int pixelIter = 0; pixelIter < pixelbytesLenght; pixelIter++)
{
reconXPixel[pixelIter] = (byte)(reconAPixel[pixelIter] + tempPixel[pixelIter]);
unfilteredScanline[scanLineIter + pixelIter - 1] = reconXPixel[pixelIter];
reconAPixel[pixelIter] = reconXPixel[pixelIter];
}
}
}
else if (tempScanline[0] == 2)
{
// Console.WriteLine("--- Filter method 2: Up ---");
//Actual and previous used pixel (in bytes)
byte[] tempPixel = new byte[pixelbytesLenght];
byte[] reconBPixel = new byte[pixelbytesLenght]; // recon(b) - pixel above actual pixel (tempPiexl)
if (datastreamScanlineIter == 0)
{
previousReconScanline = new byte[scanlineLenght];
}
else
{
previousReconScanline = CutFromDatastream(refilteredDatastream, (datastreamIter - datastreamScanlineIter) - (scanlineLenght - 1), scanlineLenght - 1);
}
for (int scanLineIter = 1; scanLineIter < tempScanline.Length; scanLineIter += pixelbytesLenght) // scanLineIter=1 becouse of filter byte
{
//Update pixel data
for (int k = 0; k < pixelbytesLenght; k++)
{
tempPixel[k] = tempScanline[scanLineIter + k];
}
for (int k = 0; k < pixelbytesLenght; k++)
{
reconBPixel[k] = previousReconScanline[scanLineIter - 1 + k];
}
for (int pixelIter = 0; pixelIter < pixelbytesLenght; pixelIter++)
{
unfilteredScanline[scanLineIter + pixelIter - 1] = (byte)(reconBPixel[pixelIter] + tempPixel[pixelIter]);
}
}
}
else if (tempScanline[0] == 3)
{
// Console.WriteLine("--- Filter method 3: Average ---");
byte[] tempPixel = new byte[pixelbytesLenght]; //Actual and previous used pixel (in bytes)
byte[] reconBPixel = new byte[pixelbytesLenght]; // recon(b) - pixel above actual pixel (tempPiexl)
byte[] reconAPixel = new byte[pixelbytesLenght]; // recon(a) - pixel on the left to actual pixel (tempPiexl)
byte[] reconXPixel = new byte[pixelbytesLenght]; // recon(x) - reconstructed actual pixel;
if (datastreamScanlineIter == 0)
{
previousReconScanline = new byte[scanlineLenght]; // stores 0 if there is no previously reconstructed scanline
}
else
{
previousReconScanline = CutFromDatastream(refilteredDatastream, (datastreamIter - datastreamScanlineIter) - (scanlineLenght - 1), scanlineLenght - 1);
}
// Pixel on the left from the first pixel in scanline stores 0 values
for (int k = 0; k < pixelbytesLenght; k++)
{
reconAPixel[k] = 0;
}
for (int scanLineIter = 1; scanLineIter < tempScanline.Length; scanLineIter += pixelbytesLenght) // scanLineIter=1 becouse of filter byte
{
//Update pixel data
for (int k = 0; k < pixelbytesLenght; k++)
{
tempPixel[k] = tempScanline[scanLineIter + k];
}
for (int k = 0; k < pixelbytesLenght; k++)
{
reconBPixel[k] = previousReconScanline[scanLineIter - 1 + k];
}
for (int pixelIter = 0; pixelIter < pixelbytesLenght; pixelIter++)
{
reconXPixel[pixelIter] = (byte)(tempPixel[pixelIter] + (reconBPixel[pixelIter] + reconAPixel[pixelIter]) / 2);
unfilteredScanline[scanLineIter + pixelIter - 1] = reconXPixel[pixelIter];
reconAPixel[pixelIter] = reconXPixel[pixelIter];
}
}
}
else if (tempScanline[0] == 4)
{
// Console.WriteLine("--- Filter method 4: PaethPredictor ---");
byte[] tempPixel = new byte[pixelbytesLenght];
byte[] reconAPixel = new byte[pixelbytesLenght]; // aPixel - pixel on the left to actual pixel
byte[] reconAPixel2 = new byte[pixelbytesLenght];
byte[] reconBPixel = new byte[pixelbytesLenght]; // bPixel - pixel above actual pixel
byte[] reconCPixel = new byte[pixelbytesLenght]; // cPixel - pixel on the left to bPixel pixel
byte[] reconXPixel = new byte[pixelbytesLenght]; // recon(x) - reconstructed actual pixel;
byte[] reconPPixel = new byte[pixelbytesLenght];
if (datastreamScanlineIter == 0)
{
previousReconScanline = new byte[scanlineLenght]; // stores 0 if there is no previously reconstructed scanline
}
else
{
previousReconScanline = CutFromDatastream(refilteredDatastream, (datastreamIter - datastreamScanlineIter) - (scanlineLenght - 1), scanlineLenght - 1);
}
for (int k = 0; k < pixelbytesLenght; k++)
{
// Pixel on the left from the first pixel in scanline stores 0 values
reconAPixel[k] = 0;
// Pixel on the above-left from the first pixel in scanline stores 0 values
reconCPixel[k] = 0;
// Pixel on the above from the first pixel in scanline stores 0 values
reconBPixel[k] = 0;
}
for (int scanLineIter = 1; scanLineIter < tempScanline.Length; scanLineIter += pixelbytesLenght) // scanLineIter=1 becouse of filter byte
{
//Update pixel data
if (datastreamScanlineIter != 0)
{
for (int k = 0; k < pixelbytesLenght; k++)
{
reconBPixel[k] = previousReconScanline[scanLineIter - 1 + k];
}
}
if (scanLineIter != 1)
{
for (int k = 0; k < pixelbytesLenght; k++)
{
reconCPixel[k] = previousReconScanline[scanLineIter - 1 - pixelbytesLenght + k];
}
}
for (int k = 0; k < pixelbytesLenght; k++)
{
tempPixel[k] = tempScanline[scanLineIter + k];
reconAPixel2[k] = reconAPixel[k];
reconXPixel[k] = 0;
reconPPixel[k] = 0;
}
for (int pixelIter = 0; pixelIter < pixelbytesLenght; pixelIter++)
{
int p, pa, pb, pc = 0;
p = (reconAPixel2[pixelIter] + reconBPixel[pixelIter] - reconCPixel[pixelIter]);
pa = (Math.Abs(p - reconAPixel[pixelIter]));
pb = (Math.Abs(p - reconBPixel[pixelIter]));
pc = (Math.Abs(p - reconCPixel[pixelIter]));
if (pa <= pb && pa <= pc)
{
reconPPixel[pixelIter] = reconAPixel2[pixelIter];
}
else if (pb <= pc)
{
reconPPixel[pixelIter] = reconBPixel[pixelIter];
}
else
{
reconPPixel[pixelIter] = reconCPixel[pixelIter];
}
int x = (tempPixel[pixelIter] + reconPPixel[pixelIter]);
reconXPixel[pixelIter] = (byte)(tempPixel[pixelIter] + reconPPixel[pixelIter]);
unfilteredScanline[scanLineIter + pixelIter - 1] = reconXPixel[pixelIter];
reconAPixel[pixelIter] = reconXPixel[pixelIter];
}
}
}
else
{
Console.WriteLine(" WRONG METHOD CODE !!!: " + tempScanline[0] + " Scanline: " + datastreamScanlineIter);
//NOTHING TO DO - FILTER 0
//for (int scanLineIter = 1; scanLineIter < tempScanline.Length; scanLineIter++)
//{
// unfilteredScanline[scanLineIter - 1] = tempScanline[scanLineIter];
//}
}
// Fill refilteredDatastream with refiltered scanLine
int refilteredDatastreamIter = datastreamScanlineIter * (scanlineLenght - 1);
for (int k = 0; k < scanlineLenght - 1; k++) // k=1 becouse of filter byte
{
refilteredDatastream[refilteredDatastreamIter + k] = unfilteredScanline[k];
}
}
return(refilteredDatastream);
}
