public static GifExtension ReadExtension(Stream stream, IEnumerable <GifExtension> controlExtensions, bool metadataOnly)
{
//Note: at this point, the Extension Introducer (0x21) has already been read
var label = stream.ReadByte();
if (label < 0)
{
throw GifHelpers.UnexpectedEndOfStreamException();
}
switch (label)
{
case GifGraphicControlExtension.ExtensionLabel:
return(GifGraphicControlExtension.ReadGraphicsControl(stream));
case GifCommentExtension.ExtensionLabel:
return(GifCommentExtension.ReadComment(stream));
case GifPlainTextExtension.ExtensionLabel:
return(GifPlainTextExtension.ReadPlainText(stream, controlExtensions, metadataOnly));
case GifApplicationExtension.ExtensionLabel:
return(GifApplicationExtension.ReadApplication(stream));
default:
throw GifHelpers.UnknownExtensionTypeException(label);
}
}
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];
var 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 (0xFE) has already been read
var bytes = GifHelpers.ReadDataBlocks(stream, false);
if (bytes != null)
{
Text = Encoding.ASCII.GetString(bytes);
}
}
private async Task<Stream> GetIndexStreamAsync(GifFrame frame, CancellationToken cancellationToken)
{
var data = frame.ImageData;
cancellationToken.ThrowIfCancellationRequested();
_sourceStream.Seek(data.CompressedDataStartOffset, SeekOrigin.Begin);
using (var ms = new MemoryStream(_indexStreamBuffer))
{
await GifHelpers.CopyDataBlocksToStreamAsync(_sourceStream, ms, cancellationToken).ConfigureAwait(false);
}
var lzwStream = new LzwDecompressStream(_indexStreamBuffer, data.LzwMinimumCodeSize);
return lzwStream;
}
private void Read(Stream stream, IEnumerable <GifExtension> controlExtensions, bool metadataOnly)
{
//Note: at this point, the Image Separator (0x2C) has already been read
Descriptor = GifImageDescriptor.ReadImageDescriptor(stream);
if (Descriptor.HasLocalColorTable)
{
LocalColorTable = GifHelpers.ReadColorTable(stream, Descriptor.LocalColorTableSize);
}
ImageData = GifImageData.ReadImageData(stream, metadataOnly);
Extensions = controlExtensions.ToList().AsReadOnly();
}
private void Read(Stream stream, bool metadataOnly)
{
Header = GifHeader.ReadHeader(stream);
if (Header.LogicalScreenDescriptor.HasGlobalColorTable)
{
GlobalColorTable = GifHelpers.ReadColorTable(stream, Header.LogicalScreenDescriptor.GlobalColorTableSize);
}
ReadFrames(stream, metadataOnly);
var netscapeExtension = Extensions.OfType <GifApplicationExtension>().FirstOrDefault(GifHelpers.IsNetscapeExtension);
RepeatCount = netscapeExtension != null?GifHelpers.GetRepeatCount(netscapeExtension) : (ushort)1;
}
private static async Task DecompressAllFramesAsync(string path)
{
using var fileStream = File.OpenRead(path);
var gif = await GifDataStream.ReadAsync(fileStream);
for (int i = 0; i < gif.Frames.Count; i++)
{
var frame = gif.Frames[i];
fileStream.Seek(frame.ImageData.CompressedDataStartOffset, SeekOrigin.Begin);
using var ms = new MemoryStream();
await GifHelpers.CopyDataBlocksToStreamAsync(fileStream, ms);
using var lzwStream = new LzwDecompressStream(ms.GetBuffer(), frame.ImageData.LzwMinimumCodeSize);
using var indOutStream = File.OpenWrite($"{path}.{i}.ind");
await lzwStream.CopyToAsync(indOutStream);
}
}
private void Read(Stream stream)
{
Signature = GifHelpers.ReadString(stream, 3);
if (Signature != "GIF")
{
throw GifHelpers.InvalidSignatureException(Signature);
}
Version = GifHelpers.ReadString(stream, 3);
if (Version != "87a" && Version != "89a")
{
throw GifHelpers.UnsupportedVersionException(Version);
}
LogicalScreenDescriptor = GifLogicalScreenDescriptor.ReadLogicalScreenDescriptor(stream);
}
private static async Task TestLzwDecompressionAsync(string path)
{
using (var fileStream = File.OpenRead(path))
{
var gif = await GifDataStream.ReadAsync(fileStream);
var firstFrame = gif.Frames[0];
fileStream.Seek(firstFrame.ImageData.CompressedDataStartOffset, SeekOrigin.Begin);
using (var ms = new MemoryStream())
{
await GifHelpers.CopyDataBlocksToStreamAsync(fileStream, ms);
using (var lzwStream = new LzwDecompressStream(ms.GetBuffer(), firstFrame.ImageData.LzwMinimumCodeSize))
using (var indOutStream = File.OpenWrite(path + ".ind"))
{
await lzwStream.CopyToAsync(indOutStream);
}
}
}
}
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);
}
var 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];
}
private async Task <Stream> GetIndexStreamAsync(GifFrame frame, CancellationToken cancellationToken)
{
GifImageData data = frame.ImageData;
cancellationToken.ThrowIfCancellationRequested();
this._sourceStream.Seek(data.CompressedDataStartOffset, SeekOrigin.Begin);
MemoryStream ms = new MemoryStream(this._indexStreamBuffer);
try
{
await GifHelpers.CopyDataBlocksToStreamAsync(this._sourceStream, (Stream)ms, cancellationToken).ConfigureAwait(false);
}
finally
{
if (ms != null)
{
((IDisposable)ms).Dispose();
}
}
ms = null;
return((Stream) new LzwDecompressStream(this._indexStreamBuffer, (int)data.LzwMinimumCodeSize));
}
private async Task CreateGifAsync(bool isBranded)
{
BitmapImage bitmap;
var images = await GifHelpers.LoadImagesAsync(isBranded, ResultsEmojis);
//create the gif
if (images.Count > 0)
{
bitmap = await GifHelpers.CreateGifBitmapImageAsync(isBranded, images, ResultsEmojis);
if (isBranded)
{
brandedGif.Source = bitmap;
}
else
{
Gif.Source = bitmap;
}
}
else //no gif was created due to lack of recorded images
{
//hide what should have been included with the gif
if (isBranded)
{
brandedGif.Visibility = Visibility.Collapsed;
}
else
{
Gif.Visibility = Visibility.Collapsed;
OopsEmojiGifReplacement.Visibility = Visibility.Visible;
BestMomentsText.Visibility = Visibility.Collapsed;
Emoji8Logo.Visibility = Visibility.Collapsed;
ShareButton.IsEnabled = false;
}
}
}
public static GifBlock ReadBlock(Stream stream, IEnumerable <GifExtension> controlExtensions, bool metadataOnly)
{
var blockId = stream.ReadByte();
if (blockId < 0)
{
throw GifHelpers.UnexpectedEndOfStreamException();
}
switch (blockId)
{
case GifExtension.ExtensionIntroducer:
return(GifExtension.ReadExtension(stream, controlExtensions, metadataOnly));
case GifFrame.ImageSeparator:
return(GifFrame.ReadFrame(stream, controlExtensions, metadataOnly));
case GifTrailer.TrailerByte:
return(GifTrailer.ReadTrailer());
default:
throw GifHelpers.UnknownBlockTypeException(blockId);
}
}
private void Read(Stream stream, bool metadataOnly)
{
LzwMinimumCodeSize = (byte)stream.ReadByte();
CompressedData = GifHelpers.ReadDataBlocks(stream, metadataOnly);
}
