Umbraco-CMS/src/Umbraco.Infrastructure/Media/ImageSharpDimensionExtractor.cs

using System;
using System.IO;
using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Metadata.Profiles.Exif;
using Umbraco.Cms.Core.Media;
using Size = System.Drawing.Size;

namespace Umbraco.Cms.Infrastructure.Media
{
    internal class ImageSharpDimensionExtractor : IImageDimensionExtractor
    {
        private readonly Configuration _configuration;

        /// <summary>
        /// Initializes a new instance of the <see cref="ImageSharpDimensionExtractor" /> class.
        /// </summary>
        /// <param name="configuration">The configuration.</param>
        public ImageSharpDimensionExtractor(Configuration configuration)
            => _configuration = configuration;

        /// <summary>
        /// Gets the dimensions of an image.
        /// </summary>
        /// <param name="stream">A stream containing the image bytes.</param>
        /// <returns>
        /// The dimension of the image.
        /// </returns>
        public Size? GetDimensions(Stream? stream)
        {
            Size? size = null;

            IImageInfo imageInfo = Image.Identify(_configuration, stream);
            if (imageInfo != null)
            {
                size = IsExifOrientationRotated(imageInfo)
                    ? new Size(imageInfo.Height, imageInfo.Width)
                    : new Size(imageInfo.Width, imageInfo.Height);
            }

            return size;
        }

        private static bool IsExifOrientationRotated(IImageInfo imageInfo)
            => GetExifOrientation(imageInfo) switch
            {
                ExifOrientationMode.LeftTop
                or ExifOrientationMode.RightTop
                or ExifOrientationMode.RightBottom
                or ExifOrientationMode.LeftBottom => true,
                _ => false,
            };

        private static ushort GetExifOrientation(IImageInfo imageInfo)
        {
            IExifValue<ushort>? orientation = imageInfo.Metadata.ExifProfile?.GetValue(ExifTag.Orientation);
            if (orientation is not null)
            {
                if (orientation.DataType == ExifDataType.Short)
                {
                    return orientation.Value;
                }
                else
                {
                    return Convert.ToUInt16(orientation.Value);
                }
            }

            return ExifOrientationMode.Unknown;
        }
    }
}