public void InsertData(uint width, uint height, byte[] data)
{
int bufferSize = (int)((width + 1) * height);
MemoryStream idatRawStream = new MemoryStream(bufferSize);
for (uint row = 0; row < height; row++)
{
// Filter type byte
idatRawStream.WriteByte(0);
// Assuming data is row-major indices
idatRawStream.Write(data, (int)(row * width), (int)width);
}
MemoryStream idatStream = new MemoryStream(4);
using (DeflateStream compressStream = new DeflateStream(idatStream, CompressionLevel.NoCompression))
{
byte[] rawData = idatRawStream.GetBuffer();
compressStream.Write(rawData, 0, rawData.Length);
}
byte[] idatData = idatStream.GetBuffer();
Console.WriteLine($"Compressed {bufferSize} bytes to {idatData.Length} bytes.");
PNGChunk idatChunk = new PNGChunk("IDAT", idatData);
chunks.AddLast(idatChunk);
}
public void InsertTransparency(byte transparentColour = 0)
{
LinkedListNode <PNGChunk> palChunk;
foreach (var chunk in chunks)
{
if (chunk.Type == "PLTE")
{
palChunk = chunks.Find(chunk);
uint palLength = chunk.Length / 3;
byte[] transData = new byte[palLength];
for (int i = 0; i < palLength; i++)
{
if (i == transparentColour)
{
transData[i] = 0;
}
else
{
transData[i] = 255;
}
}
PNGChunk transChunk = new PNGChunk("tRNS", transData);
chunks.AddAfter(palChunk, transChunk);
break;
}
}
}
private void WriteChunk(Stream stream, PNGChunk chunk)
{
WriteBigEndian(stream, chunk.Length);
byte[] typeBytes = Encoding.ASCII.GetBytes(chunk.Type);
stream.Write(typeBytes, 0, 4);
if (chunk.Length > 0)
{
stream.Write(chunk.Data, 0, (int)chunk.Length);
}
WriteBigEndian(stream, chunk.CRC);
}
public void InsertGrabChunk(int xOffset, int yOffset)
{
byte[] grabData = new byte[8];
MemoryStream stream = new MemoryStream(grabData);
WriteBigEndian(stream, xOffset);
WriteBigEndian(stream, yOffset);
stream.Close();
PNGChunk grabChunk = new PNGChunk("grAb", grabData);
if (grabChunkNode == null)
{
grabChunkNode = chunks.AddAfter(ihdrChunkNode, grabChunk);
}
else
{
grabChunkNode.Value = grabChunk;
}
}
public void InsertHeader(uint width, uint height, byte depth = 8, byte colourType = 3, byte compression = 0, byte filter = 0, byte interlace = 0)
{
string ihdrType = "IHDR";
byte[] data = new byte[13];
MemoryStream stream = new MemoryStream(data);
WriteBigEndian(stream, width);
WriteBigEndian(stream, height);
stream.WriteByte(depth);
stream.WriteByte(colourType);
stream.WriteByte(compression);
stream.WriteByte(filter);
stream.WriteByte(interlace);
stream.Close();
PNGChunk ihdrChunk = new PNGChunk(ihdrType, data);
ihdrChunkNode = chunks.AddFirst(ihdrChunk);
}
public void InsertPalette(Color[] Palette, byte transparentColour = 0, LinkedListNode <PNGChunk> after = null)
{
byte[] plteData = new byte[Palette.Length * 3];
byte[] trnsData = new byte[Palette.Length];
MemoryStream palStream = new MemoryStream(plteData);
MemoryStream transStream = new MemoryStream(trnsData);
foreach (Color colour in Palette)
{
palStream.WriteByte(colour.R);
palStream.WriteByte(colour.G);
palStream.WriteByte(colour.B);
}
palStream.Close();
for (int i = 0; i < Palette.Length; i++)
{
if (i == transparentColour)
{
transStream.WriteByte(0); // Transparent
}
else
{
transStream.WriteByte(255); // Opaque
}
}
transStream.Close();
PNGChunk plteChunk = new PNGChunk("PLTE", plteData);
PNGChunk trnsChunk = new PNGChunk("tRNS", trnsData);
if (after != null)
{
chunks.AddAfter(after, trnsChunk); // PLTE will go first
chunks.AddAfter(after, plteChunk);
}
else
{
chunks.AddLast(plteChunk);
chunks.AddLast(trnsChunk);
}
}
public bool Read()
{
byte[] header = binaryReader.ReadBytes(8);
int comparison = 0;
for (int i = 0; i < PNGHead.Length; i++)
{
comparison += PNGHead[i] ^ header[i];
}
if (comparison > 0)
{
return(false);
}
while (binaryReader.BaseStream.Position < binaryReader.BaseStream.Length)
{
uint length = ReadBigEndian();
string type = Encoding.ASCII.GetString(binaryReader.ReadBytes(4));
byte[] data;
if (length > 0)
{
data = binaryReader.ReadBytes((int)length);
}
else
{
data = new byte[] { };
}
uint crc = ReadBigEndian();
PNGChunk chunk = new PNGChunk(length, type, crc, data);
chunks.AddLast(chunk);
if (type == "IHDR")
{
ihdrChunkNode = chunks.Last;
}
}
binaryReader.Close();
return(true);
}
public void InsertEnd()
{
PNGChunk endChunk = new PNGChunk("IEND");
chunks.AddLast(endChunk);
}
