/// <summary>
/// Generates thumbnails asynchronously
/// </summary>
/// <param name="sourcePath">Path to source picture</param>
/// <param name="destPath">Target for generated thumbnail</param>
/// <param name="options">Represents generation options</param>
/// <param name="token">Allows cancel operation</param>
/// <returns></returns>
public virtual async Task <ThumbnailGenerationResult> GenerateThumbnailsAsync(string sourcePath, string destPath, IList <ThumbnailOption> options, ICancellationToken token)
{
token?.ThrowIfCancellationRequested();
var originalImage = await _imageService.LoadImageAsync(sourcePath, out var format);
if (originalImage == null)
{
return(new ThumbnailGenerationResult
{
Errors = { $"Cannot generate thumbnail: {sourcePath} does not have a valid image format" }
});
}
var result = new ThumbnailGenerationResult();
foreach (var option in options)
{
var thumbnail = GenerateThumbnail(originalImage, option);
var thumbnailUrl = sourcePath.GenerateThumbnailName(option.FileSuffix);
if (thumbnail != null)
{
await _imageService.SaveImageAsync(thumbnailUrl, thumbnail, format, option.JpegQuality);
}
else
{
throw new Exception($"Cannot save thumbnail image {thumbnailUrl}");
}
result.GeneratedThumbnails.Add(thumbnailUrl);
}
return(result);
}
/// <summary>
/// Generates thumbnails asynchronously
/// </summary>
/// <param name="sourcePath">Path to source picture</param>
/// <param name="destPath">Target for generated thumbnail</param>
/// <param name="options">Represents generation options</param>
/// <param name="token">Allows cancel operation</param>
/// <returns></returns>
public async Task <ThumbnailGenerationResult> GenerateThumbnailsAsync(string sourcePath, string destPath, IList <ThumbnailOption> options, ICancellationToken token)
{
token?.ThrowIfCancellationRequested();
var originalImage = await _imageService.LoadImageAsync(sourcePath);
if (originalImage == null)
{
return(new ThumbnailGenerationResult
{
Errors = { $"Cannot generate thumbnail: {sourcePath} does not have a valid image format" }
});
}
var result = new ThumbnailGenerationResult();
var format = _imageService.GetImageFormat(originalImage);
//one process only can use an Image object at the same time.
Image clone;
lock (_progressLock)
{
clone = (Image)originalImage.Clone();
}
foreach (var option in options)
{
var thumbnail = GenerateThumbnail(clone, option);
var thumbnailUrl = sourcePath.GenerateThumbnailName(option.FileSuffix);
if (thumbnail != null)
{
await _imageService.SaveImage(thumbnailUrl, thumbnail, format);
}
else
{
throw new Exception($"Cannot save thumbnail image {thumbnailUrl}");
}
result.GeneratedThumbnails.Add(thumbnailUrl);
}
return(result);
}
