/// <summary>
/// Create a thumbnail image from the input. The thumbnail is taken from the image file in the case that the file has one.
/// Otherwise it will be a new image that is created from the image file.
/// </summary>
/// <param name="decoder">Bitmap decoder.</param>
/// <param name="expectedWidth"> Expected width.</param>
/// <param name="expectedHeight">Expected height.</param>
/// <returns>a new image with smallest size that is larger than the input dimension.</returns>
public static async Task <SoftwareBitmap> CreateThumbnail(BitmapDecoder decoder, uint expectedWidth, uint expectedHeight)
{
BitmapDecoder decoder2;
try
{
var thumbnail = await decoder.GetThumbnailAsync();
decoder2 = await BitmapDecoder.CreateAsync(thumbnail);
}
catch
{
decoder2 = null;
}
if (decoder2 == null)
{
try
{
var preview = await decoder.GetPreviewAsync();
decoder2 = await BitmapDecoder.CreateAsync(preview);
}
catch
{
decoder2 = null;
}
}
if (decoder2 == null)
{
decoder2 = decoder;
}
return(await CreateResizedBitmap(decoder2, expectedWidth, expectedHeight, BitmapInterpolationMode.Linear));
}
