public async Task <IDecodedImage <Bitmap> > DecodeAsync(Stream stream, string path, ImageSource source, ImageInformation imageInformation, TaskParameter parameters)
{
var result = new DecodedImage <Bitmap>();
using (var gifDecoder = new GifHelper())
{
var insampleSize = 1;
// DOWNSAMPLE
if (parameters.DownSampleSize != null && (parameters.DownSampleSize.Item1 > 0 || parameters.DownSampleSize.Item2 > 0))
{
// Calculate inSampleSize
var downsampleWidth = parameters.DownSampleSize.Item1;
var downsampleHeight = parameters.DownSampleSize.Item2;
if (parameters.DownSampleUseDipUnits)
{
downsampleWidth = downsampleWidth.DpToPixels();
downsampleHeight = downsampleHeight.DpToPixels();
}
await gifDecoder.ReadHeaderAsync(stream).ConfigureAwait(false);
insampleSize = BaseDecoder.CalculateInSampleSize(gifDecoder.Width, gifDecoder.Height, downsampleWidth, downsampleHeight, false);
}
await gifDecoder.ReadAsync(stream, insampleSize).ConfigureAwait(false);
gifDecoder.Advance();
imageInformation.SetOriginalSize(gifDecoder.Width, gifDecoder.Height);
if (insampleSize > 1)
{
imageInformation.SetCurrentSize(gifDecoder.DownsampledWidth, gifDecoder.DownsampledHeight);
}
else
{
imageInformation.SetCurrentSize(gifDecoder.Width, gifDecoder.Height);
}
result.IsAnimated = gifDecoder.FrameCount > 1 && Configuration.AnimateGifs;
if (result.IsAnimated && Configuration.AnimateGifs)
{
result.AnimatedImages = new AnimatedImage <Bitmap> [gifDecoder.FrameCount];
for (var i = 0; i < gifDecoder.FrameCount; i++)
{
var animatedImage = new AnimatedImage <Bitmap>
{
Delay = gifDecoder.GetDelay(i),
Image = await gifDecoder.GetNextFrameAsync()
};
result.AnimatedImages[i] = animatedImage;
gifDecoder.Advance();
}
}
else
{
result.IsAnimated = false;
result.Image = await gifDecoder.GetNextFrameAsync();
}
if (result.Image != null)
{
imageInformation.SetOriginalSize(result.Image.Width, result.Image.Height);
imageInformation.SetCurrentSize(result.Image.Width, result.Image.Height);
}
else if (result.AnimatedImages != null)
{
if (result.AnimatedImages.Length > 0)
{
if (result.AnimatedImages[0].Image != null)
{
imageInformation.SetOriginalSize(result.AnimatedImages[0].Image.Width, result.AnimatedImages[0].Image.Height);
imageInformation.SetCurrentSize(result.AnimatedImages[0].Image.Width, result.AnimatedImages[0].Image.Height);
}
}
}
return(result);
}
}