public async Task <Stream> GetAsync(IImageAssetRenderable asset, IImageResizeSettings inputSettings)
{
if ((inputSettings.Width < 1 && inputSettings.Height < 1) ||
(inputSettings.Width == asset.Width && inputSettings.Height == asset.Height))
{
return(await GetFileStreamAsync(asset.ImageAssetId));
}
if (_imageAssetsSettings.DisableResizing)
{
throw new InvalidImageResizeSettingsException("Image resizing has been requested but is disabled.", inputSettings);
}
var fullFileName = asset.FileNameOnDisk + "/" + CreateCacheFileName(inputSettings, asset);
Stream imageStream = null;
ValidateSettings(inputSettings);
if (await _fileService.ExistsAsync(IMAGE_ASSET_CACHE_CONTAINER_NAME, fullFileName))
{
return(await _fileService.GetAsync(IMAGE_ASSET_CACHE_CONTAINER_NAME, fullFileName));
}
else
{
imageStream = new MemoryStream();
IImageFormat imageFormat = null;
using (var originalStream = await GetFileStreamAsync(asset.ImageAssetId))
using (var image = Image.Load(originalStream, out imageFormat))
{
if (imageFormat == null)
{
throw new Exception("Unable to determine image type for image asset " + asset.ImageAssetId);
}
var encoder = Configuration.Default.ImageFormatsManager.FindEncoder(imageFormat);
if (encoder == null)
{
throw new InvalidOperationException("Encoder not found for image format " + imageFormat.Name);
}
var resizeOptions = ConvertSettings(inputSettings);
image.Mutate(cx =>
{
cx.Resize(resizeOptions);
if (!string.IsNullOrWhiteSpace(inputSettings.BackgroundColor))
{
var color = Rgba32.ParseHex(inputSettings.BackgroundColor);
cx.BackgroundColor(color);
}
else if (CanPad(resizeOptions))
{
if (SupportsTransparency(imageFormat))
{
cx.BackgroundColor(Color.Transparent);
encoder = EnsureEncoderSupportsTransparency(encoder);
}
else
{
// default background for jpg encoder is black, but white is a better default in most scenarios.
cx.BackgroundColor(Color.White);
}
}
});
image.Save(imageStream, encoder);
}
try
{
// Try and create the cache file, but don't throw an error if it fails - it will be attempted again on the next request
await _fileService.CreateIfNotExistsAsync(IMAGE_ASSET_CACHE_CONTAINER_NAME, fullFileName, imageStream);
}
catch (Exception ex)
{
if (Debugger.IsAttached)
{
throw;
}
else
{
_logger.LogError(0, ex, "Error creating image asset cache file. Container name {ContainerName}, {fullFileName}", IMAGE_ASSET_CACHE_CONTAINER_NAME, fullFileName);
}
}
imageStream.Position = 0;
return(imageStream);
}
}