Remove ImageFormat out params and return on Metadata

src/ImageSharp/Advanced/AdvancedImageExtensions.cs

@@ -19,9 +19,9 @@ public static class AdvancedImageExtensions
     /// </summary>
     /// <param name="source">The source image.</param>
     /// <param name="filePath">The target file path to save the image to.</param>
-    /// <exception cref="ArgumentNullException">The file path is null.</exception>
-    /// <exception cref="NotSupportedException">No encoder available for provided path.</exception>
     /// <returns>The matching <see cref="IImageEncoder"/>.</returns>
+    /// <exception cref="ArgumentNullException">The file path is null.</exception>
+    /// <exception cref="UnknownImageFormatException">No encoder available for provided path.</exception>
     public static IImageEncoder DetectEncoder(this Image source, string filePath)
     {
         Guard.NotNull(filePath, nameof(filePath));
@@ -30,27 +30,27 @@ public static IImageEncoder DetectEncoder(this Image source, string filePath)
         if (!source.GetConfiguration().ImageFormatsManager.TryFindFormatByFileExtension(ext, out IImageFormat? format))
         {
             StringBuilder sb = new();
-            sb.AppendLine(CultureInfo.InvariantCulture, $"No encoder was found for extension '{ext}'. Registered encoders include:");
+            sb = sb.AppendLine(CultureInfo.InvariantCulture, $"No encoder was found for extension '{ext}'. Registered encoders include:");
             foreach (IImageFormat fmt in source.GetConfiguration().ImageFormats)
             {
-                sb.AppendFormat(CultureInfo.InvariantCulture, " - {0} : {1}{2}", fmt.Name, string.Join(", ", fmt.FileExtensions), Environment.NewLine);
+                sb = sb.AppendFormat(CultureInfo.InvariantCulture, " - {0} : {1}{2}", fmt.Name, string.Join(", ", fmt.FileExtensions), Environment.NewLine);
             }
 
-            throw new NotSupportedException(sb.ToString());
+            throw new UnknownImageFormatException(sb.ToString());
         }
 
-        IImageEncoder? encoder = source.GetConfiguration().ImageFormatsManager.FindEncoder(format);
+        IImageEncoder? encoder = source.GetConfiguration().ImageFormatsManager.GetEncoder(format);
 
         if (encoder is null)
         {
             StringBuilder sb = new();
-            sb.AppendLine(CultureInfo.InvariantCulture, $"No encoder was found for extension '{ext}' using image format '{format.Name}'. Registered encoders include:");
+            sb = sb.AppendLine(CultureInfo.InvariantCulture, $"No encoder was found for extension '{ext}' using image format '{format.Name}'. Registered encoders include:");
             foreach (KeyValuePair<IImageFormat, IImageEncoder> enc in source.GetConfiguration().ImageFormatsManager.ImageEncoders)
             {
-                sb.AppendFormat(CultureInfo.InvariantCulture, " - {0} : {1}{2}", enc.Key, enc.Value.GetType().Name, Environment.NewLine);
+                sb = sb.AppendFormat(CultureInfo.InvariantCulture, " - {0} : {1}{2}", enc.Key, enc.Value.GetType().Name, Environment.NewLine);
             }
 
-            throw new NotSupportedException(sb.ToString());
+            throw new UnknownImageFormatException(sb.ToString());
         }
 
         return encoder;

src/ImageSharp/Formats/Bmp/BmpDecoder.cs

@@ -20,7 +20,7 @@ private BmpDecoder()
     public static BmpDecoder Instance { get; } = new();
 
     /// <inheritdoc/>
-    protected override IImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
+    protected override ImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
     {
         Guard.NotNull(options, nameof(options));
         Guard.NotNull(stream, nameof(stream));

src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs

@@ -209,7 +209,7 @@ public Image<TPixel> Decode<TPixel>(BufferedReadStream stream, CancellationToken
     }
 
     /// <inheritdoc />
-    public IImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken)
+    public ImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken)
     {
         this.ReadImageHeaders(stream, out _, out _);
         return new ImageInfo(new PixelTypeInfo(this.infoHeader.BitsPerPixel), this.infoHeader.Width, this.infoHeader.Height, this.metadata);

src/ImageSharp/Formats/Gif/GifDecoder.cs

@@ -20,7 +20,7 @@ private GifDecoder()
     public static GifDecoder Instance { get; } = new();
 
     /// <inheritdoc/>
-    protected override IImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
+    protected override ImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
     {
         Guard.NotNull(options, nameof(options));
         Guard.NotNull(stream, nameof(stream));

src/ImageSharp/Formats/Gif/GifDecoderCore.cs

@@ -175,7 +175,7 @@ public Image<TPixel> Decode<TPixel>(BufferedReadStream stream, CancellationToken
     }
 
     /// <inheritdoc />
-    public IImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken)
+    public ImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken)
     {
         try
         {

src/ImageSharp/Formats/IImageDecoder.cs

@@ -15,9 +15,9 @@ public interface IImageDecoder
     /// </summary>
     /// <param name="options">The general decoder options.</param>
     /// <param name="stream">The <see cref="Stream"/> containing image data.</param>
-    /// <returns>The <see cref="IImageInfo"/> object.</returns>
+    /// <returns>The <see cref="ImageInfo"/> object.</returns>
     /// <exception cref="ImageFormatException">Thrown if the encoded image contains errors.</exception>
-    public IImageInfo Identify(DecoderOptions options, Stream stream);
+    public ImageInfo Identify(DecoderOptions options, Stream stream);
 
     /// <summary>
     /// Reads the raw image information from the specified stream.
@@ -27,7 +27,7 @@ public interface IImageDecoder
     /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
     /// <returns>The <see cref="Task{IImageInfo}"/> object.</returns>
     /// <exception cref="ImageFormatException">Thrown if the encoded image contains errors.</exception>
-    public Task<IImageInfo> IdentifyAsync(DecoderOptions options, Stream stream, CancellationToken cancellationToken = default);
+    public Task<ImageInfo> IdentifyAsync(DecoderOptions options, Stream stream, CancellationToken cancellationToken = default);
 
     /// <summary>
     /// Decodes the image from the specified stream to an <see cref="Image{TPixel}"/> of a specific pixel type.

src/ImageSharp/Formats/IImageDecoderInternals.cs

@@ -41,10 +41,10 @@ Image<TPixel> Decode<TPixel>(BufferedReadStream stream, CancellationToken cancel
     /// </summary>
     /// <param name="stream">The <see cref="BufferedReadStream"/> containing image data.</param>
     /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
-    /// <returns>The <see cref="IImageInfo"/>.</returns>
+    /// <returns>The <see cref="ImageInfo"/>.</returns>
     /// <remarks>
     /// Cancellable synchronous method. In case of cancellation,
     /// an <see cref="OperationCanceledException"/> shall be thrown which will be handled on the call site.
     /// </remarks>
-    IImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken);
+    ImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken);
 }

src/ImageSharp/Formats/ImageDecoder.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.PixelFormats;
@@ -17,49 +16,85 @@ public abstract class ImageDecoder : IImageDecoder
     /// <inheritdoc/>
     public Image<TPixel> Decode<TPixel>(DecoderOptions options, Stream stream)
         where TPixel : unmanaged, IPixel<TPixel>
-        => WithSeekableStream(
-              options,
-              stream,
-              s => this.Decode<TPixel>(options, s, default));
+    {
+        Image<TPixel> image = WithSeekableStream(
+            options,
+            stream,
+            s => this.Decode<TPixel>(options, s, default));
+
+        this.SetDecoderFormat(options.Configuration, image);
+
+        return image;
+    }
 
     /// <inheritdoc/>
     public Image Decode(DecoderOptions options, Stream stream)
-        => WithSeekableStream(
-              options,
-              stream,
-              s => this.Decode(options, s, default));
+    {
+        Image image = WithSeekableStream(
+            options,
+            stream,
+            s => this.Decode(options, s, default));
+
+        this.SetDecoderFormat(options.Configuration, image);
+
+        return image;
+    }
 
     /// <inheritdoc/>
-    public Task<Image<TPixel>> DecodeAsync<TPixel>(DecoderOptions options, Stream stream, CancellationToken cancellationToken = default)
+    public async Task<Image<TPixel>> DecodeAsync<TPixel>(DecoderOptions options, Stream stream, CancellationToken cancellationToken = default)
         where TPixel : unmanaged, IPixel<TPixel>
-        => WithSeekableMemoryStreamAsync(
-            options,
-            stream,
-            (s, ct) => this.Decode<TPixel>(options, s, ct),
-            cancellationToken);
+    {
+        Image<TPixel> image = await WithSeekableMemoryStreamAsync(
+                options,
+                stream,
+                (s, ct) => this.Decode<TPixel>(options, s, ct),
+                cancellationToken).ConfigureAwait(false);
+
+        this.SetDecoderFormat(options.Configuration, image);
+
+        return image;
+    }
 
     /// <inheritdoc/>
-    public Task<Image> DecodeAsync(DecoderOptions options, Stream stream, CancellationToken cancellationToken = default)
-        => WithSeekableMemoryStreamAsync(
+    public async Task<Image> DecodeAsync(DecoderOptions options, Stream stream, CancellationToken cancellationToken = default)
+    {
+        Image image = await WithSeekableMemoryStreamAsync(
             options,
             stream,
             (s, ct) => this.Decode(options, s, ct),
-            cancellationToken);
+            cancellationToken).ConfigureAwait(false);
+
+        this.SetDecoderFormat(options.Configuration, image);
+
+        return image;
+    }
 
     /// <inheritdoc/>
-    public IImageInfo Identify(DecoderOptions options, Stream stream)
-          => WithSeekableStream(
-              options,
-              stream,
-              s => this.Identify(options, s, default));
+    public ImageInfo Identify(DecoderOptions options, Stream stream)
+    {
+        ImageInfo info = WithSeekableStream(
+            options,
+            stream,
+            s => this.Identify(options, s, default));
+
+        this.SetDecoderFormat(options.Configuration, info);
+
+        return info;
+    }
 
     /// <inheritdoc/>
-    public Task<IImageInfo> IdentifyAsync(DecoderOptions options, Stream stream, CancellationToken cancellationToken = default)
-         => WithSeekableMemoryStreamAsync(
-             options,
-             stream,
-             (s, ct) => this.Identify(options, s, ct),
-             cancellationToken);
+    public async Task<ImageInfo> IdentifyAsync(DecoderOptions options, Stream stream, CancellationToken cancellationToken = default)
+    {
+        ImageInfo info = await WithSeekableMemoryStreamAsync(
+            options,
+            stream,
+            (s, ct) => this.Identify(options, s, ct),
+            cancellationToken).ConfigureAwait(false);
+
+        this.SetDecoderFormat(options.Configuration, info);
+
+        return info;
+    }
 
     /// <summary>
     /// Decodes the image from the specified stream to an <see cref="Image{TPixel}" /> of a specific pixel type.
@@ -98,9 +133,9 @@ protected abstract Image<TPixel> Decode<TPixel>(DecoderOptions options, Stream s
     /// <param name="options">The general decoder options.</param>
     /// <param name="stream">The <see cref="Stream"/> containing image data.</param>
     /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
-    /// <returns>The <see cref="IImageInfo"/> object.</returns>
+    /// <returns>The <see cref="ImageInfo"/> object.</returns>
     /// <exception cref="ImageFormatException">Thrown if the encoded image contains errors.</exception>
-    protected abstract IImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken);
+    protected abstract ImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken);
 
     /// <summary>
     /// Performs a scaling operation against the decoded image. If the target size is not set, or the image size
@@ -114,7 +149,7 @@ protected static void ScaleToTargetSize(DecoderOptions options, Image image)
         {
             ResizeOptions resizeOptions = new()
             {
-                Size = options.TargetSize.Value,
+                Size = options.TargetSize!.Value,
                 Sampler = options.Sampler,
                 Mode = ResizeMode.Max
             };
@@ -252,4 +287,20 @@ private static async Task<T> CopyToMemoryStreamAndActionAsync<T>(
         memoryStream.Position = 0;
         return await action(memoryStream, position, cancellationToken).ConfigureAwait(false);
     }
+
+    internal void SetDecoderFormat(Configuration configuration, Image image)
+    {
+        if (configuration.ImageFormatsManager.TryFindFormatByDecoder(this, out IImageFormat? format))
+        {
+            image.Metadata.DecodedImageFormat = format;
+        }
+    }
+
+    internal void SetDecoderFormat(Configuration configuration, ImageInfo info)
+    {
+        if (configuration.ImageFormatsManager.TryFindFormatByDecoder(this, out IImageFormat? format))
+        {
+            info.Metadata.DecodedImageFormat = format;
+        }
+    }
 }

src/ImageSharp/Formats/ImageDecoderUtilities.cs

@@ -12,7 +12,7 @@ namespace SixLabors.ImageSharp.Formats;
 /// </summary>
 internal static class ImageDecoderUtilities
 {
-    internal static IImageInfo Identify(
+    internal static ImageInfo Identify(
         this IImageDecoderInternals decoder,
         Configuration configuration,
         Stream stream,