Refactor Bmp and Gif

src/ImageSharp/Formats/Bmp/BmpDecoder.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
 using System.IO;
@@ -10,43 +10,31 @@ namespace SixLabors.ImageSharp.Formats.Bmp
     /// <summary>
     /// Image decoder for generating an image out of a Windows bitmap stream.
     /// </summary>
-    /// <remarks>
-    /// Does not support the following formats at the moment:
-    /// <list type="bullet">
-    ///    <item>JPG</item>
-    ///    <item>PNG</item>
-    ///    <item>Some OS/2 specific subtypes like: Bitmap Array, Color Icon, Color Pointer, Icon, Pointer.</item>
-    /// </list>
-    /// Formats will be supported in a later releases. We advise always
-    /// to use only 24 Bit Windows bitmaps.
-    /// </remarks>
-    public sealed class BmpDecoder : IImageDecoder, IBmpDecoderOptions, IImageInfoDetector
+    public class BmpDecoder : ImageDecoder<BmpDecoderOptions>
     {
-        /// <summary>
-        /// Gets or sets a value indicating how to deal with skipped pixels, which can occur during decoding run length encoded bitmaps.
-        /// </summary>
-        public RleSkippedPixelHandling RleSkippedPixelHandling { get; set; } = RleSkippedPixelHandling.Black;
-
         /// <inheritdoc/>
-        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream, CancellationToken cancellationToken)
-            where TPixel : unmanaged, IPixel<TPixel>
+        public override Image<TPixel> DecodeSpecialized<TPixel>(BmpDecoderOptions options, Stream stream, CancellationToken cancellationToken)
         {
             Guard.NotNull(stream, nameof(stream));
 
-            var decoder = new BmpDecoderCore(configuration, this);
-            return decoder.Decode<TPixel>(configuration, stream, cancellationToken);
+            BmpDecoderCore decoder = new(options);
+            Image<TPixel> image = decoder.Decode<BmpDecoderOptions, TPixel>(options.GeneralOptions.Configuration, stream, cancellationToken);
+
+            Resize(options.GeneralOptions, image);
+
+            return image;
         }
 
-        /// <inheritdoc />
-        public Image Decode(Configuration configuration, Stream stream, CancellationToken cancellationToken)
-            => this.Decode<Rgba32>(configuration, stream, cancellationToken);
+        /// <inheritdoc/>
+        public override Image DecodeSpecialized(BmpDecoderOptions options, Stream stream, CancellationToken cancellationToken)
+            => this.DecodeSpecialized<Rgba32>(options, stream, cancellationToken);
 
         /// <inheritdoc/>
-        public IImageInfo Identify(Configuration configuration, Stream stream, CancellationToken cancellationToken)
+        public override IImageInfo IdentifySpecialized(BmpDecoderOptions options, Stream stream, CancellationToken cancellationToken)
         {
             Guard.NotNull(stream, nameof(stream));
 
-            return new BmpDecoderCore(configuration, this).Identify(configuration, stream, cancellationToken);
+            return new BmpDecoderCore(options).Identify(options.GeneralOptions.Configuration, stream, cancellationToken);
         }
     }
 }

src/ImageSharp/Formats/Bmp/BmpDecoder2.cs

@@ -1,30 +0,0 @@
-// Copyright (c) Six Labors.
-// Licensed under the Apache License, Version 2.0.
-
-using System;
-using System.IO;
-using System.Threading;
-using SixLabors.ImageSharp.PixelFormats;
-
-namespace SixLabors.ImageSharp.Formats.Bmp
-{
-    /// <summary>
-    /// Image decoder for generating an image out of a Windows bitmap stream.
-    /// </summary>
-    public class BmpDecoder2 : ImageDecoder<BmpDecoderOptions>
-    {
-        /// <inheritdoc/>
-        public override Image<TPixel> DecodeSpecialized<TPixel>(BmpDecoderOptions options, Stream stream, CancellationToken cancellationToken)
-        {
-            throw new NotImplementedException();
-        }
-
-        /// <inheritdoc/>
-        public override Image DecodeSpecialized(BmpDecoderOptions options, Stream stream, CancellationToken cancellationToken)
-            => this.DecodeSpecialized<Rgba32>(options, stream, cancellationToken);
-
-        /// <inheritdoc/>
-        public override IImageInfo IdentifySpecialized(BmpDecoderOptions options, Stream stream, CancellationToken cancellationToken)
-            => throw new NotImplementedException();
-    }
-}

src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs

@@ -22,7 +22,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
     /// <remarks>
     /// A useful decoding source example can be found at <see href="https://dxr.mozilla.org/mozilla-central/source/image/decoders/nsBMPDecoder.cpp"/>
     /// </remarks>
-    internal sealed class BmpDecoderCore : IImageDecoderInternals
+    internal sealed class BmpDecoderCore : IImageDecoderInternals<BmpDecoderOptions>
     {
         /// <summary>
         /// The default mask for the red part of the color for 16 bit rgb bitmaps.
@@ -90,33 +90,30 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         private BmpInfoHeader infoHeader;
 
         /// <summary>
-        /// Used for allocating memory during processing operations.
+        /// The global configuration.
         /// </summary>
-        private readonly MemoryAllocator memoryAllocator;
+        private readonly Configuration configuration;
 
         /// <summary>
-        /// The bitmap decoder options.
+        /// Used for allocating memory during processing operations.
         /// </summary>
-        private readonly IBmpDecoderOptions options;
+        private readonly MemoryAllocator memoryAllocator;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="BmpDecoderCore"/> class.
         /// </summary>
-        /// <param name="configuration">The configuration.</param>
         /// <param name="options">The options.</param>
-        public BmpDecoderCore(Configuration configuration, IBmpDecoderOptions options)
+        public BmpDecoderCore(BmpDecoderOptions options)
         {
-            this.Configuration = configuration;
-            this.memoryAllocator = configuration.MemoryAllocator;
-            this.options = options;
+            this.configuration = options.GeneralOptions.Configuration;
+            this.memoryAllocator = this.configuration.MemoryAllocator;
+            this.Options = options;
         }
 
         /// <inheritdoc />
-        public Configuration Configuration { get; }
+        public BmpDecoderOptions Options { get; }
 
-        /// <summary>
-        /// Gets the dimensions of the image.
-        /// </summary>
+        /// <inheritdoc />
         public Size Dimensions => new(this.infoHeader.Width, this.infoHeader.Height);
 
         /// <inheritdoc />
@@ -128,7 +125,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
             {
                 int bytesPerColorMapEntry = this.ReadImageHeaders(stream, out bool inverted, out byte[] palette);
 
-                image = new Image<TPixel>(this.Configuration, this.infoHeader.Width, this.infoHeader.Height, this.metadata);
+                image = new Image<TPixel>(this.configuration, this.infoHeader.Width, this.infoHeader.Height, this.metadata);
 
                 Buffer2D<TPixel> pixels = image.GetRootFramePixelBuffer();
 
@@ -325,7 +322,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                             byte colorIdx = bufferRow[x];
                             if (undefinedPixelsSpan[rowStartIdx + x])
                             {
-                                switch (this.options.RleSkippedPixelHandling)
+                                switch (this.Options.RleSkippedPixelHandling)
                                 {
                                     case RleSkippedPixelHandling.FirstColorOfPalette:
                                         color.FromBgr24(Unsafe.As<byte, Bgr24>(ref colors[colorIdx * 4]));
@@ -397,7 +394,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                             int idx = rowStartIdx + (x * 3);
                             if (undefinedPixelsSpan[yMulWidth + x])
                             {
-                                switch (this.options.RleSkippedPixelHandling)
+                                switch (this.Options.RleSkippedPixelHandling)
                                 {
                                     case RleSkippedPixelHandling.FirstColorOfPalette:
                                         color.FromBgr24(Unsafe.As<byte, Bgr24>(ref bufferSpan[idx]));
@@ -943,7 +940,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                 int newY = Invert(y, height, inverted);
                 Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(newY);
                 PixelOperations<TPixel>.Instance.FromBgr24Bytes(
-                    this.Configuration,
+                    this.configuration,
                     rowSpan,
                     pixelSpan,
                     width);
@@ -971,7 +968,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                 int newY = Invert(y, height, inverted);
                 Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(newY);
                 PixelOperations<TPixel>.Instance.FromBgra32Bytes(
-                    this.Configuration,
+                    this.configuration,
                     rowSpan,
                     pixelSpan,
                     width);
@@ -1006,7 +1003,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                 this.stream.Read(rowSpan);
 
                 PixelOperations<Bgra32>.Instance.FromBgra32Bytes(
-                    this.Configuration,
+                    this.configuration,
                     rowSpan,
                     bgraRowSpan,
                     width);
@@ -1042,7 +1039,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                     Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(newY);
 
                     PixelOperations<TPixel>.Instance.FromBgra32Bytes(
-                        this.Configuration,
+                        this.configuration,
                         rowSpan,
                         pixelSpan,
                         width);
@@ -1056,7 +1053,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
             {
                 this.stream.Read(rowSpan);
                 PixelOperations<Bgra32>.Instance.FromBgra32Bytes(
-                    this.Configuration,
+                    this.configuration,
                     rowSpan,
                     bgraRowSpan,
                     width);

src/ImageSharp/Formats/Bmp/BmpDecoderOptions.cs

@@ -4,7 +4,7 @@
 namespace SixLabors.ImageSharp.Formats.Bmp
 {
     /// <summary>
-    /// Image decoder options for decoding Windows bitmap streams.
+    /// Configuration options for decoding Windows Bitmap images.
     /// </summary>
     public sealed class BmpDecoderOptions : ISpecializedDecoderOptions
     {

src/ImageSharp/Formats/Bmp/IBmpDecoderOptions.cs

@@ -1,16 +0,0 @@
-// Copyright (c) Six Labors.
-// Licensed under the Apache License, Version 2.0.
-
-namespace SixLabors.ImageSharp.Formats.Bmp
-{
-    /// <summary>
-    /// Image decoder options for decoding Windows bitmap streams.
-    /// </summary>
-    internal interface IBmpDecoderOptions
-    {
-        /// <summary>
-        /// Gets the value indicating how to deal with skipped pixels, which can occur during decoding run length encoded bitmaps.
-        /// </summary>
-        RleSkippedPixelHandling RleSkippedPixelHandling { get; }
-    }
-}

src/ImageSharp/Formats/DecoderOptions.cs

@@ -24,10 +24,8 @@ namespace SixLabors.ImageSharp.Formats
         public bool SkipMetadata { get; set; } = false;
 
         /// <summary>
-        /// Gets or sets the number of image frames to decode.
-        /// Leave <see langword="null"/> to decode all frames.
+        /// Gets or sets the maximum number of image frames to decode, inclusive.
         /// </summary>
-        // supported decoders may handle this internally but we will fallback to removeing additional frames after decode.
-        public int? MaxFrames { get; set; } = null;
+        public int MaxFrames { get; set; } = int.MaxValue;
     }
 }

src/ImageSharp/Formats/Gif/GifDecoder.cs

@@ -3,7 +3,6 @@
 
 using System.IO;
 using System.Threading;
-using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats.Gif
@@ -11,37 +10,29 @@ namespace SixLabors.ImageSharp.Formats.Gif
     /// <summary>
     /// Decoder for generating an image out of a gif encoded stream.
     /// </summary>
-    public sealed class GifDecoder : IImageDecoder, IGifDecoderOptions, IImageInfoDetector
+    public sealed class GifDecoder : ImageDecoder<GifDecoderOptions>
     {
-        /// <summary>
-        /// Gets or sets a value indicating whether the metadata should be ignored when the image is being decoded.
-        /// </summary>
-        public bool IgnoreMetadata { get; set; } = false;
-
-        /// <summary>
-        /// Gets or sets the decoding mode for multi-frame images
-        /// </summary>
-        public FrameDecodingMode DecodingMode { get; set; } = FrameDecodingMode.All;
-
         /// <inheritdoc/>
-        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream, CancellationToken cancellationToken)
-            where TPixel : unmanaged, IPixel<TPixel>
+        public override Image<TPixel> DecodeSpecialized<TPixel>(GifDecoderOptions options, Stream stream, CancellationToken cancellationToken)
         {
-            var decoder = new GifDecoderCore(configuration, this);
-            return decoder.Decode<TPixel>(configuration, stream, cancellationToken);
+            GifDecoderCore decoder = new(options);
+            Image<TPixel> image = decoder.Decode<GifDecoderOptions, TPixel>(options.GeneralOptions.Configuration, stream, cancellationToken);
+
+            Resize(options.GeneralOptions, image);
+
+            return image;
         }
 
-        /// <inheritdoc />
-        public Image Decode(Configuration configuration, Stream stream, CancellationToken cancellationToken)
-            => this.Decode<Rgba32>(configuration, stream, cancellationToken);
+        /// <inheritdoc/>
+        public override Image DecodeSpecialized(GifDecoderOptions options, Stream stream, CancellationToken cancellationToken)
+            => this.DecodeSpecialized<Rgba32>(options, stream, cancellationToken);
 
         /// <inheritdoc/>
-        public IImageInfo Identify(Configuration configuration, Stream stream, CancellationToken cancellationToken)
+        public override IImageInfo IdentifySpecialized(GifDecoderOptions options, Stream stream, CancellationToken cancellationToken)
         {
             Guard.NotNull(stream, nameof(stream));
 
-            var decoder = new GifDecoderCore(configuration, this);
-            return decoder.Identify(configuration, stream, cancellationToken);
+            return new GifDecoderCore(options).Identify(options.GeneralOptions.Configuration, stream, cancellationToken);
         }
     }
 }

src/ImageSharp/Formats/Gif/GifDecoderCore.cs

@@ -19,7 +19,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
     /// <summary>
     /// Performs the gif decoding operation.
     /// </summary>
-    internal sealed class GifDecoderCore : IImageDecoderInternals
+    internal sealed class GifDecoderCore : IImageDecoderInternals<GifDecoderOptions>
     {
         /// <summary>
         /// The temp buffer used to reduce allocations.
@@ -56,6 +56,26 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// </summary>
         private GifImageDescriptor imageDescriptor;
 
+        /// <summary>
+        /// The global configuration.
+        /// </summary>
+        private readonly Configuration configuration;
+
+        /// <summary>
+        /// Used for allocating memory during processing operations.
+        /// </summary>
+        private readonly MemoryAllocator memoryAllocator;
+
+        /// <summary>
+        /// The maximum number of frames to decode.
+        /// </summary>
+        private readonly int maxFrames;
+
+        /// <summary>
+        /// Whether to skip metadata during decode.
+        /// </summary>
+        private readonly bool skipMetadata;
+
         /// <summary>
         /// The abstract metadata.
         /// </summary>
@@ -69,39 +89,26 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <summary>
         /// Initializes a new instance of the <see cref="GifDecoderCore"/> class.
         /// </summary>
-        /// <param name="configuration">The configuration.</param>
         /// <param name="options">The decoder options.</param>
-        public GifDecoderCore(Configuration configuration, IGifDecoderOptions options)
+        public GifDecoderCore(GifDecoderOptions options)
         {
-            this.IgnoreMetadata = options.IgnoreMetadata;
-            this.DecodingMode = options.DecodingMode;
-            this.Configuration = configuration ?? Configuration.Default;
+            this.skipMetadata = options.GeneralOptions.SkipMetadata;
+            this.configuration = options.GeneralOptions.Configuration;
+            this.memoryAllocator = this.configuration.MemoryAllocator;
+            this.maxFrames = options.GeneralOptions.MaxFrames;
         }
 
         /// <inheritdoc />
-        public Configuration Configuration { get; }
-
-        /// <summary>
-        /// Gets or sets a value indicating whether the metadata should be ignored when the image is being decoded.
-        /// </summary>
-        public bool IgnoreMetadata { get; internal set; }
+        public GifDecoderOptions Options { get; }
 
-        /// <summary>
-        /// Gets the decoding mode for multi-frame images.
-        /// </summary>
-        public FrameDecodingMode DecodingMode { get; }
-
-        /// <summary>
-        /// Gets the dimensions of the image.
-        /// </summary>
+        /// <inheritdoc />
         public Size Dimensions => new(this.imageDescriptor.Width, this.imageDescriptor.Height);
 
-        private MemoryAllocator MemoryAllocator => this.Configuration.MemoryAllocator;
-
         /// <inheritdoc />
         public Image<TPixel> Decode<TPixel>(BufferedReadStream stream, CancellationToken cancellationToken)
             where TPixel : unmanaged, IPixel<TPixel>
         {
+            int frameCount = 0;
             Image<TPixel> image = null;
             ImageFrame<TPixel> previousFrame = null;
             try
@@ -114,7 +121,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
                 {
                     if (nextFlag == GifConstants.ImageLabel)
                     {
-                        if (previousFrame != null && this.DecodingMode == FrameDecodingMode.First)
+                        if (previousFrame != null && frameCount++ <= this.maxFrames)
                         {
                             break;
                         }
@@ -277,9 +284,9 @@ namespace SixLabors.ImageSharp.Formats.Gif
                 this.stream.Read(this.buffer, 0, GifConstants.ApplicationBlockSize);
                 bool isXmp = this.buffer.AsSpan().StartsWith(GifConstants.XmpApplicationIdentificationBytes);
 
-                if (isXmp && !this.IgnoreMetadata)
+                if (isXmp && !this.skipMetadata)
                 {
-                    var extension = GifXmpApplicationExtension.Read(this.stream, this.MemoryAllocator);
+                    var extension = GifXmpApplicationExtension.Read(this.stream, this.memoryAllocator);
                     if (extension.Data.Length > 0)
                     {
                         this.metadata.XmpProfile = new XmpProfile(extension.Data);
@@ -346,13 +353,13 @@ namespace SixLabors.ImageSharp.Formats.Gif
                     GifThrowHelper.ThrowInvalidImageContentException($"Gif comment length '{length}' exceeds max '{GifConstants.MaxCommentSubBlockLength}' of a comment data block");
                 }
 
-                if (this.IgnoreMetadata)
+                if (this.skipMetadata)
                 {
                     this.stream.Seek(length, SeekOrigin.Current);
                     continue;
                 }
 
-                using IMemoryOwner<byte> commentsBuffer = this.MemoryAllocator.Allocate<byte>(length);
+                using IMemoryOwner<byte> commentsBuffer = this.memoryAllocator.Allocate<byte>(length);
                 Span<byte> commentsSpan = commentsBuffer.GetSpan();
 
                 this.stream.Read(commentsSpan);
@@ -385,11 +392,11 @@ namespace SixLabors.ImageSharp.Formats.Gif
                 if (this.imageDescriptor.LocalColorTableFlag)
                 {
                     int length = this.imageDescriptor.LocalColorTableSize * 3;
-                    localColorTable = this.Configuration.MemoryAllocator.Allocate<byte>(length, AllocationOptions.Clean);
+                    localColorTable = this.configuration.MemoryAllocator.Allocate<byte>(length, AllocationOptions.Clean);
                     this.stream.Read(localColorTable.GetSpan());
                 }
 
-                indices = this.Configuration.MemoryAllocator.Allocate2D<byte>(this.imageDescriptor.Width, this.imageDescriptor.Height, AllocationOptions.Clean);
+                indices = this.configuration.MemoryAllocator.Allocate2D<byte>(this.imageDescriptor.Width, this.imageDescriptor.Height, AllocationOptions.Clean);
                 this.ReadFrameIndices(indices);
 
                 Span<byte> rawColorTable = default;
@@ -423,7 +430,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         private void ReadFrameIndices(Buffer2D<byte> indices)
         {
             int minCodeSize = this.stream.ReadByte();
-            using var lzwDecoder = new LzwDecoder(this.Configuration.MemoryAllocator, this.stream);
+            using var lzwDecoder = new LzwDecoder(this.configuration.MemoryAllocator, this.stream);
             lzwDecoder.DecodePixels(minCodeSize, indices);
         }
 
@@ -451,12 +458,12 @@ namespace SixLabors.ImageSharp.Formats.Gif
             {
                 if (!transFlag)
                 {
-                    image = new Image<TPixel>(this.Configuration, imageWidth, imageHeight, Color.Black.ToPixel<TPixel>(), this.metadata);
+                    image = new Image<TPixel>(this.configuration, imageWidth, imageHeight, Color.Black.ToPixel<TPixel>(), this.metadata);
                 }
                 else
                 {
                     // This initializes the image to become fully transparent because the alpha channel is zero.
-                    image = new Image<TPixel>(this.Configuration, imageWidth, imageHeight, this.metadata);
+                    image = new Image<TPixel>(this.configuration, imageWidth, imageHeight, this.metadata);
                 }
 
                 this.SetFrameMetadata(image.Frames.RootFrame.Metadata);
@@ -675,7 +682,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
 
                 if (globalColorTableLength > 0)
                 {
-                    this.globalColorTable = this.MemoryAllocator.Allocate<byte>(globalColorTableLength, AllocationOptions.Clean);
+                    this.globalColorTable = this.memoryAllocator.Allocate<byte>(globalColorTableLength, AllocationOptions.Clean);
 
                     // Read the global color table data from the stream
                     stream.Read(this.globalColorTable.GetSpan());

src/ImageSharp/Formats/Gif/GifDecoderOptions.cs

@@ -0,0 +1,14 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.Gif
+{
+    /// <summary>
+    /// Configuration options for decoding Gif images.
+    /// </summary>
+    public sealed class GifDecoderOptions : ISpecializedDecoderOptions
+    {
+        /// <inheritdoc/>
+        public DecoderOptions GeneralOptions { get; set; } = new();
+    }
+}

src/ImageSharp/Formats/IImageDecoderInternals.cs → src/ImageSharp/Formats/IImageDecoderInternals{T}.cs

@@ -9,14 +9,16 @@ using SixLabors.ImageSharp.PixelFormats;
 namespace SixLabors.ImageSharp.Formats
 {
     /// <summary>
-    /// Abstraction for shared internals for ***DecoderCore implementations to be used with <see cref="ImageDecoderUtilities"/>.
+    /// Abstraction for shared internals for XXXDecoderCore implementations to be used with <see cref="ImageDecoderUtilities"/>.
     /// </summary>
-    internal interface IImageDecoderInternals
+    /// <typeparam name="T">The type of specialized decoder options.</typeparam>
+    internal interface IImageDecoderInternals<T>
+        where T : ISpecializedDecoderOptions
     {
         /// <summary>
-        /// Gets the associated configuration.
+        /// Gets the specialized decoder options.
         /// </summary>
-        Configuration Configuration { get; }
+        T Options { get; }
 
         /// <summary>
         /// Gets the dimensions of the image being decoded.

src/ImageSharp/Formats/ImageDecoderUtilities.cs

@@ -12,11 +12,12 @@ namespace SixLabors.ImageSharp.Formats
 {
     internal static class ImageDecoderUtilities
     {
-        public static IImageInfo Identify(
-            this IImageDecoderInternals decoder,
+        public static IImageInfo Identify<T>(
+            this IImageDecoderInternals<T> decoder,
             Configuration configuration,
             Stream stream,
             CancellationToken cancellationToken)
+            where T : ISpecializedDecoderOptions
         {
             using var bufferedReadStream = new BufferedReadStream(configuration, stream);
 
@@ -30,20 +31,22 @@ namespace SixLabors.ImageSharp.Formats
             }
         }
 
-        public static Image<TPixel> Decode<TPixel>(
-            this IImageDecoderInternals decoder,
+        public static Image<TPixel> Decode<T, TPixel>(
+            this IImageDecoderInternals<T> decoder,
             Configuration configuration,
             Stream stream,
             CancellationToken cancellationToken)
+            where T : ISpecializedDecoderOptions
             where TPixel : unmanaged, IPixel<TPixel>
-            => decoder.Decode<TPixel>(configuration, stream, DefaultLargeImageExceptionFactory, cancellationToken);
+            => decoder.Decode<T, TPixel>(configuration, stream, DefaultLargeImageExceptionFactory, cancellationToken);
 
-        public static Image<TPixel> Decode<TPixel>(
-            this IImageDecoderInternals decoder,
+        public static Image<TPixel> Decode<T, TPixel>(
+            this IImageDecoderInternals<T> decoder,
             Configuration configuration,
             Stream stream,
             Func<InvalidMemoryOperationException, Size, InvalidImageContentException> largeImageExceptionFactory,
             CancellationToken cancellationToken)
+            where T : ISpecializedDecoderOptions
             where TPixel : unmanaged, IPixel<TPixel>
         {
             using var bufferedReadStream = new BufferedReadStream(configuration, stream);