private static async Task <Animator> CreateAsync(Stream sourceStream, Uri sourceUri, RepeatBehavior repeatBehavior, Image image)
{
Stream stream = sourceStream.AsBuffered();
GifDataStream metadata = await GifDataStream.ReadAsync(stream);
return(new Animator(stream, sourceUri, metadata, repeatBehavior, image));
}
internal static async Task<TAnimator> CreateAsyncCore<TAnimator>(
Stream sourceStream,
Func<GifDataStream, TAnimator> create)
where TAnimator : Animator
{
var metadata = await GifDataStream.ReadAsync(sourceStream);
return create(metadata);
}
internal static async Task <TAnimator> CreateAsyncCore <TAnimator>(
Stream sourceStream,
Func <GifDataStream, TAnimator> create)
where TAnimator : Animator
{
if (!sourceStream.CanSeek)
{
throw new ArgumentException("The stream is not seekable");
}
sourceStream.Seek(0, SeekOrigin.Begin);
var metadata = await GifDataStream.ReadAsync(sourceStream);
return(create(metadata));
}
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 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);
}
}
}
}
