public override Task ConvertAsync(IList <Image <Rgba32> > images, Stream outputStream, CancellationToken cancellationToken)
{
if (images is null)
{
throw new ArgumentNullException(nameof(images));
}
if (images.Count != 2)
{
throw new ArgumentException("Exactly two images are required for this format.", nameof(images));
}
if (outputStream is null)
{
throw new ArgumentNullException(nameof(outputStream));
}
// This format appears to use 9 mipmaps. The first is the biggest at 256x256 (this is the max supported).
// Each subsequent one is half as wide and high, ending with 1x1. This makes 9 images.
// `Math.Log(256, 2) + 1` (+ 1 because 2^0 = 1 and that's still a slot we need) can be
// used to calculate this value, but since we're going up against file size limits anyway,
// hard-coding is fine.
const int totalImages = 9;
var sizedImages = new List <Image <Rgba32> >(totalImages);
sizedImages.AddRange(images.Take(totalImages));
var lastImage = sizedImages.Last();
while (sizedImages.Count < totalImages)
{
sizedImages.Add(lastImage.Clone());
}
var width = MaxWidth;
var height = MaxHeight;
foreach (var image in sizedImages)
{
ResizeUtil.Resize(image, width, height);
width /= 2;
height /= 2;
lastImage = image;
}
var encoder = new VtfEncoder(VtfImageType.Fading);
return(encoder.EncodeWithMipmapsAsync(sizedImages, outputStream, cancellationToken));
}
public override async Task ConvertAsync(IList <Image <Rgba32> > images,
Stream outputStream, CancellationToken cancellationToken)
{
if (images is null)
{
throw new ArgumentNullException(nameof(images));
}
if (images.Count != 1)
{
throw new ArgumentException("Only one image is permitted for this format.", nameof(images));
}
if (outputStream is null)
{
throw new ArgumentNullException(nameof(outputStream));
}
var image = images[0];
Resize(image);
var encoder = new VtfEncoder(VtfImageType.Single1024);
await image.SaveAsync(outputStream, encoder, cancellationToken);
}
