public static byte[] DecompressIDATs(List <Chunk> chunks)
{
List <IDAT> idats = chunks.Where(IsIDAT).Select(chunk => (IDAT)chunk).ToList();
byte[] bytes = IDATConverter.ConcatToBytes(idats);
byte[] decompressedBytes = ZlibCompression.Decompress(bytes);
return(decompressedBytes);
}
public void ShouldConcatDecompressCompressAndThenSplitImage()
{
string filePath = @"../../../Data/lena.png";
List <Chunk> chunks = PNGFile.Read(filePath);
List <Chunk> parsedChunks = ChunkParser.Parse(chunks);
int firstIdatIndex = parsedChunks.TakeWhile(chunk => !IsIDAT(chunk)).Count();
List <IDAT> idats = parsedChunks.Where(IsIDAT).Select(chunk => (IDAT)chunk).ToList();
byte[] bytes = IDATConverter.ConcatToBytes(idats);
byte[] decompressedBytes = ZlibCompression.Decompress(bytes);
byte[] compressedBytes = ZlibCompression.Compress(decompressedBytes);
List <Chunk> resultIdats = IDATConverter.SplitToIDATs(compressedBytes).Select(idat => (Chunk)idat).ToList();
List <Chunk> resultChunks = parsedChunks.Where(chunk => !IsIDAT(chunk)).ToList();
resultChunks.InsertRange(firstIdatIndex, resultIdats);
PNGFile.Write(@"../../../Data/lenaCompressed.png", resultChunks);
}
private static void CompressAndDecompress(byte[] bytes)
{
byte[] compressed = ZlibCompression.Compress(bytes);
byte[] decompressed = ZlibCompression.Decompress(compressed);
Assert.AreEqual(bytes, decompressed);
}
