/// <summary>
/// Extracts various fields specific to this chunk from the APNG's
/// data field
/// </summary>
/// <param name="chunkData">An array of bytes representing the APNG's data field</param>
protected override void ParseData(byte[] chunkData)
{
int offset = 0;
frameWidth = APNGUtility.ParseUint(chunkData, 4, ref offset);
frameHeight = APNGUtility.ParseUint(chunkData, 4, ref offset);
//ticksPerSecond = APNGUtility.ParseUint(chunkData, 4, ref offset);
//nominalLayerCount = APNGUtility.ParseUint(chunkData, 4, ref offset);
//nominalFrameCount = APNGUtility.ParseUint(chunkData, 4, ref offset);
//nominalPlayTime = APNGUtility.ParseUint(chunkData, 4, ref offset);
//simplicityProfile = APNGUtility.ParseUint(chunkData, 4, ref offset);
}
/// <summary>
/// Extracts various fields specific to this chunk from the APNG's
/// data field
/// </summary>
/// <param name="chunkData">An array of bytes representing the APNG's data field</param>
protected override void ParseData(byte[] chunkData)
{
int offset = 0;
width = APNGUtility.ParseUint(chunkData, 4, ref offset);
height = APNGUtility.ParseUint(chunkData, 4, ref offset);
bitDepth = APNGUtility.ParseUint(chunkData, 1, ref offset);
colorType = APNGUtility.ParseUint(chunkData, 1, ref offset);
compressionMethod = APNGUtility.ParseUint(chunkData, 1, ref offset);
filterMethod = APNGUtility.ParseUint(chunkData, 1, ref offset);
interlaceMethod = APNGUtility.ParseUint(chunkData, 1, ref offset);
}
/// <summary>
/// Extracts various fields specific to this chunk from the APNG's
/// data field
/// </summary>
/// <param name="chunkData">An array of bytes representing the APNG's data field</param>
protected override void ParseData(byte[] chunkData)
{
int offset = 0;
terminationAction = APNGUtility.ParseUint(chunkData, 1, ref offset);
// If the data length is > 1 then read 9 more bytes
if (chunkData.Length > 1)
{
actionAfterTermination = APNGUtility.ParseUint(chunkData, 1, ref offset);
delay = APNGUtility.ParseUint(chunkData, 4, ref offset);
iterationMax = APNGUtility.ParseUint(chunkData, 4, ref offset);
}
}
/// <summary>
/// Attempts to parse an APNGChunk for the specified stream
/// </summary>
/// <param name="stream">The stream containing the APNG Chunk</param>
public void Read(Stream stream)
{
if (!stream.CanRead)
{
throw new ArgumentException("Stream is not readable");
}
calculatedCRC = CRC.INITIAL_CRC;
long chunkStart = stream.Position;
// Read the data Length
chunkLength = APNGUtility.ReadStream(stream, 4);
// Read the chunk type
chunkType = APNGUtility.ReadStream(stream, 4);
calculatedCRC = CRC.UpdateCRC(calculatedCRC, chunkType);
// Read the data
chunkData = APNGUtility.ReadStream(stream, ChunkLength);
calculatedCRC = CRC.UpdateCRC(calculatedCRC, chunkData);
// Read the CRC
chunkCRC = APNGUtility.ReadStream(stream, 4);
// CRC is inverted
calculatedCRC = ~calculatedCRC;
// Verify the CRC
if (ChunkCRC != calculatedCRC)
{
StringBuilder sb = new StringBuilder();
sb.AppendLine(String.Format("APNG Chunk CRC Mismatch. Chunk CRC = {0}, Calculated CRC = {1}.",
ChunkCRC, calculatedCRC));
sb.AppendLine(String.Format("This occurred while parsing the chunk at position {0} (0x{1:X8}) in the stream.",
chunkStart, chunkStart));
throw new ApplicationException(sb.ToString());
}
}
/// <summary>
/// Attempts to read an APNG Header chunk from the supplied stream.
/// </summary>
/// <param name="stream">The stream containing the APNG Header</param>
public void Read(Stream stream)
{
// Stream must be readable
if (!stream.CanRead)
{
throw new ArgumentException("Stream is not readable");
}
// Read the signature
try
{
signature = APNGUtility.ReadStream(stream, 8);
}
catch (Exception)
{
// Re-throw any exceptions
throw;
}
// Test signature for validity
if (signature.Length == expectedSignature.Length)
{
for (int i = 0; i < expectedSignature.Length; i++)
{
// Invalid signature
if (expectedSignature[i] != signature[i])
{
throw new ApplicationException("APNG signature not found.");
}
}
}
else
{
// Invalid signature
throw new ApplicationException("APNG signature not found.");
}
}
/// <summary>
/// Extracts various fields specific to this chunk from the APNG's
/// data field
/// </summary>
/// <param name="chunkData">An array of bytes representing the APNG's data field</param>
protected override void ParseData(byte[] chunkData)
{
int offset = 0;
redBackground = APNGUtility.ParseUint(chunkData, 2, ref offset);
greenBackground = APNGUtility.ParseUint(chunkData, 2, ref offset);
blueBackground = APNGUtility.ParseUint(chunkData, 2, ref offset);
// If the data length is > 6 then read 1 more byte
if (chunkData.Length > 6)
{
mandatoryBackground = APNGUtility.ParseUint(chunkData, 1, ref offset);
}
// If the data length is > 7 then read 2 more bytes
if (chunkData.Length > 7)
{
backgroundImageId = APNGUtility.ParseUint(chunkData, 2, ref offset);
}
// If the data length is > 9 then read 1 more byte
if (chunkData.Length > 9)
{
backgroundTiling = APNGUtility.ParseUint(chunkData, 1, ref offset);
}
}
