public async Task CreateThumbnailAsync(Stream source, string mimeType, Stream destination, ResizeOptions options,
CancellationToken ct = default)
{
Guard.NotNull(source, nameof(source));
Guard.NotNull(destination, nameof(destination));
Guard.NotNull(options, nameof(options));
if (!options.IsValid)
{
await source.CopyToAsync(destination, ct);
return;
}
var w = options.TargetWidth ?? 0;
var h = options.TargetHeight ?? 0;
using (var collection = new MagickImageCollection())
{
await collection.ReadAsync(source, GetFormat(mimeType), ct);
collection.Coalesce();
foreach (var image in collection)
{
var clone = image.Clone();
var color = options.ParseColor();
if (w > 0 || h > 0)
{
var isCropUpsize = options.Mode == ResizeMode.CropUpsize;
var resizeMode = options.Mode;
if (isCropUpsize)
{
resizeMode = ResizeMode.Crop;
}
if (w >= image.Width && h >= image.Height && resizeMode == ResizeMode.Crop && !isCropUpsize)
{
resizeMode = ResizeMode.BoxPad;
}
PointF?centerCoordinates = null;
if (options.FocusX.HasValue && options.FocusY.HasValue)
{
centerCoordinates = new PointF(
+(options.FocusX.Value / 2f) + 0.5f,
-(options.FocusY.Value / 2f) + 0.5f
);
}
var(size, pad) = ResizeHelper.CalculateTargetLocationAndBounds(resizeMode, new Size(image.Width, image.Height), w, h, centerCoordinates);
var sourceRectangle = new MagickGeometry(pad.Width, pad.Height)
{
IgnoreAspectRatio = true
};
clone.Resize(sourceRectangle);
image.Extent(size.Width, size.Height);
image.CompositeClear(color);
image.Composite(clone, pad.X, pad.Y, CompositeOperator.Over);
}
else
{
image.CompositeClear(color);
image.Composite(clone, 0, 0, CompositeOperator.Over);
}
image.AutoOrient();
if (options.Quality.HasValue)
{
image.Quality = options.Quality.Value;
}
}
var firstImage = collection[0];
var firstFormat = firstImage.Format;
var targetFormat = options.GetFormat(firstFormat);
await collection.WriteAsync(destination, targetFormat, ct);
}
}
