private void Read(Stream stream, IEnumerable <GifExtension> controlExtensions, bool metadataOnly)
{
// Note: at this point, the label (0x01) has already been read
var bytes = new byte[13];
stream.ReadAll(bytes, 0, bytes.Length);
BlockSize = bytes[0];
if (BlockSize != 12)
{
throw GifHelpers.InvalidBlockSizeException("Plain Text Extension", 12, BlockSize);
}
Left = BitConverter.ToUInt16(bytes, 1);
Top = BitConverter.ToUInt16(bytes, 3);
Width = BitConverter.ToUInt16(bytes, 5);
Height = BitConverter.ToUInt16(bytes, 7);
CellWidth = bytes[9];
CellHeight = bytes[10];
ForegroundColorIndex = bytes[11];
BackgroundColorIndex = bytes[12];
byte[] dataBytes = GifHelpers.ReadDataBlocks(stream, metadataOnly) !;
Text = Encoding.ASCII.GetString(dataBytes);
Extensions = controlExtensions.ToList().AsReadOnly();
}
private void Read(Stream stream)
{
// Note: at this point, the label (0xFF) has already been read
var bytes = new byte[12];
stream.ReadAll(bytes, 0, bytes.Length);
BlockSize = bytes[0]; // should always be 11
if (BlockSize != 11)
{
throw GifHelpers.InvalidBlockSizeException("Application Extension", 11, BlockSize);
}
ApplicationIdentifier = Encoding.ASCII.GetString(bytes, 1, 8);
var authCode = new byte[3];
Array.Copy(bytes, 9, authCode, 0, 3);
AuthenticationCode = authCode;
Data = GifHelpers.ReadDataBlocks(stream, false) !;
}
private void Read(Stream stream)
{
// Note: at this point, the label (0xF9) has already been read
var bytes = new byte[6];
stream.ReadAll(bytes, 0, bytes.Length);
BlockSize = bytes[0]; // should always be 4
if (BlockSize != 4)
{
throw GifHelpers.InvalidBlockSizeException("Graphic Control Extension", 4, BlockSize);
}
byte packedFields = bytes[1];
DisposalMethod = (packedFields & 0x1C) >> 2;
UserInput = (packedFields & 0x02) != 0;
HasTransparency = (packedFields & 0x01) != 0;
Delay = BitConverter.ToUInt16(bytes, 2) * 10; // milliseconds
TransparencyIndex = bytes[4];
}