Add benchmark for decoding exr image

src/ImageSharp/Configuration.cs

@@ -5,10 +5,10 @@ using System.Collections.Concurrent;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Bmp;
 using SixLabors.ImageSharp.Formats.Cur;
+using SixLabors.ImageSharp.Formats.Exr;
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Formats.Ico;
 using SixLabors.ImageSharp.Formats.Jpeg;
-using SixLabors.ImageSharp.Formats.Exr;
 using SixLabors.ImageSharp.Formats.Pbm;
 using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Formats.Qoi;

src/ImageSharp/Formats/Exr/ExrDecoder.cs

@@ -28,7 +28,7 @@ public class ExrDecoder : ImageDecoder
         return new ExrDecoderCore(new ExrDecoderOptions { GeneralOptions = options }).Identify(options.Configuration, stream, cancellationToken);
     }
 
-    //// <inheritdoc/>
+    /// <inheritdoc/>
     protected override Image<TPixel> Decode<TPixel>(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
     {
         Guard.NotNull(options, nameof(options));

src/ImageSharp/Formats/Exr/ExrDecoderCore.cs

@@ -6,7 +6,6 @@ using System.Buffers;
 using System.Buffers.Binary;
 using System.Numerics;
 using System.Runtime.CompilerServices;
-using System.Runtime.Intrinsics;
 using System.Text;
 using SixLabors.ImageSharp.Formats.Exr.Compression;
 using SixLabors.ImageSharp.Formats.Exr.Constants;
@@ -23,7 +22,6 @@ namespace SixLabors.ImageSharp.Formats.Exr;
 internal sealed class ExrDecoderCore : ImageDecoderCore
 {
     private const float Scale32Bit = 1f / 0xFFFFFFFF;
-    private static readonly Vector4 Scale32BitVector = Vector128.Create(Scale32Bit, Scale32Bit, Scale32Bit, 1f).AsVector4();
 
     /// <summary>
     /// Reusable buffer.
@@ -56,11 +54,6 @@ internal sealed class ExrDecoderCore : ImageDecoderCore
         this.memoryAllocator = this.configuration.MemoryAllocator;
     }
 
-    /// <summary>
-    /// Gets the dimensions of the image.
-    /// </summary>
-    public Size Dimensions => new(this.Width, this.Height);
-
     /// <summary>
     /// Gets or sets the image width.
     /// </summary>
@@ -81,16 +74,6 @@ internal sealed class ExrDecoderCore : ImageDecoderCore
     /// </summary>
     private ExrCompression Compression { get; set; }
 
-    /// <summary>
-    /// Gets or sets the image data type, either RGB, RGBA or gray.
-    /// </summary>
-    private ExrImageDataType ImageDataType { get; set; }
-
-    /// <summary>
-    /// Gets or sets the image type, either ScanLine or tiled.
-    /// </summary>
-    private ExrImageType ImageType { get; set; }
-
     /// <summary>
     /// Gets or sets the header attributes.
     /// </summary>
@@ -106,7 +89,6 @@ internal sealed class ExrDecoderCore : ImageDecoderCore
         }
 
         ExrPixelType pixelType = this.ValidateChannels();
-        this.ReadImageDataType();
 
         Image<TPixel> image = new(this.configuration, this.Width, this.Height, this.metadata);
         Buffer2D<TPixel> pixels = image.GetRootFramePixelBuffer();
@@ -226,7 +208,7 @@ internal sealed class ExrDecoderCore : ImageDecoderCore
                 for (int channelIdx = 0; channelIdx < this.Channels.Count; channelIdx++)
                 {
                     ExrChannelInfo channel = this.Channels[channelIdx];
-                    offset += this.ReadUnsignedIntChannelData(stream, channel, decompressedPixelData.Slice(offset), redPixelData, greenPixelData, bluePixelData, alphaPixelData, width);
+                    offset += this.ReadUnsignedIntChannelData(stream, channel, decompressedPixelData[offset..], redPixelData, greenPixelData, bluePixelData, alphaPixelData, width);
                 }
 
                 for (int x = 0; x < width; x++)
@@ -320,29 +302,18 @@ internal sealed class ExrDecoderCore : ImageDecoderCore
         }
     }
 
-    private static int ReadChannelData(ExrChannelInfo channel, Span<byte> decompressedPixelData, Span<float> pixelData, int width)
+    private static int ReadChannelData(ExrChannelInfo channel, Span<byte> decompressedPixelData, Span<float> pixelData, int width) => channel.PixelType switch
     {
-        switch (channel.PixelType)
+        ExrPixelType.Half => ReadPixelRowChannelHalfSingle(decompressedPixelData, pixelData, width),
-        {
+        ExrPixelType.Float => ReadPixelRowChannelSingle(decompressedPixelData, pixelData, width),
-            case ExrPixelType.Half:
+        _ => 0,
-                return ReadPixelRowChannelHalfSingle(decompressedPixelData, pixelData, width);
+    };
-            case ExrPixelType.Float:
-                return ReadPixelRowChannelSingle(decompressedPixelData, pixelData, width);
-        }
-
-        return 0;
-    }
 
-    private static int ReadChannelData(ExrChannelInfo channel, Span<byte> decompressedPixelData, Span<uint> pixelData, int width)
+    private static int ReadChannelData(ExrChannelInfo channel, Span<byte> decompressedPixelData, Span<uint> pixelData, int width) => channel.PixelType switch
     {
-        switch (channel.PixelType)
+        ExrPixelType.UnsignedInt => ReadPixelRowChannelUnsignedInt(decompressedPixelData, pixelData, width),
-        {
+        _ => 0,
-            case ExrPixelType.UnsignedInt:
+    };
-                return ReadPixelRowChannelUnsignedInt(decompressedPixelData, pixelData, width);
-        }
-
-        return 0;
-    }
 
     private static int ReadPixelRowChannelHalfSingle(Span<byte> decompressedPixelData, Span<float> channelData, int width)
     {
@@ -442,7 +413,7 @@ internal sealed class ExrDecoderCore : ImageDecoderCore
         byte flagsByte2 = (byte)stream.ReadByte();
         if ((flagsByte0 & (1 << 1)) != 0)
         {
-            this.ImageType = ExrImageType.Tiled;
+            ExrThrowHelper.ThrowNotSupported("Decoding tiled exr images is not supported yet!");
         }
 
         this.HeaderAttributes = this.ParseHeaderAttributes(stream);
@@ -560,7 +531,7 @@ internal sealed class ExrDecoderCore : ImageDecoderCore
 
     private List<ExrChannelInfo> ReadChannelList(BufferedReadStream stream, int attributeSize)
     {
-        List<ExrChannelInfo> channels = new();
+        List<ExrChannelInfo> channels = [];
         while (attributeSize > 1)
         {
             ExrChannelInfo channelInfo = this.ReadChannelInfo(stream, out int bytesRead);
@@ -654,76 +625,11 @@ internal sealed class ExrDecoderCore : ImageDecoderCore
         return pixelType.Value;
     }
 
-    private bool IsSupportedCompression()
+    private bool IsSupportedCompression() => this.Compression switch
-    {
-        switch (this.Compression)
-        {
-            case ExrCompression.None:
-            case ExrCompression.Zip:
-            case ExrCompression.Zips:
-            case ExrCompression.RunLengthEncoded:
-            case ExrCompression.B44:
-                return true;
-        }
-
-        return false;
-    }
-
-    private void ReadImageDataType()
     {
-        bool hasRedChannel = false;
+        ExrCompression.None or ExrCompression.Zip or ExrCompression.Zips or ExrCompression.RunLengthEncoded or ExrCompression.B44 => true,
-        bool hasGreenChannel = false;
+        _ => false,
-        bool hasBlueChannel = false;
+    };
-        bool hasAlphaChannel = false;
-        bool hasLuminance = false;
-        foreach (ExrChannelInfo channelInfo in this.Channels)
-        {
-            if (channelInfo.ChannelName.Equals("A", StringComparison.Ordinal))
-            {
-                hasAlphaChannel = true;
-            }
-
-            if (channelInfo.ChannelName.Equals("R", StringComparison.Ordinal))
-            {
-                hasRedChannel = true;
-            }
-
-            if (channelInfo.ChannelName.Equals("G", StringComparison.Ordinal))
-            {
-                hasGreenChannel = true;
-            }
-
-            if (channelInfo.ChannelName.Equals("B", StringComparison.Ordinal))
-            {
-                hasBlueChannel = true;
-            }
-
-            if (channelInfo.ChannelName.Equals("Y", StringComparison.Ordinal))
-            {
-                hasLuminance = true;
-            }
-        }
-
-        if (hasRedChannel && hasGreenChannel && hasBlueChannel && hasAlphaChannel)
-        {
-            this.ImageDataType = ExrImageDataType.Rgba;
-            return;
-        }
-
-        if (hasRedChannel && hasGreenChannel && hasBlueChannel)
-        {
-            this.ImageDataType = ExrImageDataType.Rgb;
-            return;
-        }
-
-        if (hasLuminance && this.Channels.Count == 1)
-        {
-            this.ImageDataType = ExrImageDataType.Gray;
-            return;
-        }
-
-        ExrThrowHelper.ThrowNotSupported("The image contains channels, which are not supported!");
-    }
 
     private bool HasAlpha()
     {

src/ImageSharp/Formats/Exr/ExrMetadata.cs

@@ -30,17 +30,22 @@ public class ExrMetadata : IFormatMetadata<ExrMetadata>
     /// </summary>
     public ExrPixelType PixelType { get; set; } = ExrPixelType.Float;
 
+    /// <inheritdoc/>
     public static ExrMetadata FromFormatConnectingMetadata(FormatConnectingMetadata metadata) => throw new NotImplementedException();
 
+    /// <inheritdoc/>
     public void AfterImageApply<TPixel>(Image<TPixel> destination, Matrix4x4 matrix)
         where TPixel : unmanaged, IPixel<TPixel> => throw new NotImplementedException();
 
     /// <inheritdoc/>
     public IDeepCloneable DeepClone() => new ExrMetadata(this);
 
+    /// <inheritdoc/>
     public PixelTypeInfo GetPixelTypeInfo() => throw new NotImplementedException();
 
+    /// <inheritdoc/>
     public FormatConnectingMetadata ToFormatConnectingMetadata() => throw new NotImplementedException();
 
+    /// <inheritdoc/>
     ExrMetadata IDeepCloneable<ExrMetadata>.DeepClone() => throw new NotImplementedException();
 }

src/ImageSharp/PixelFormats/PixelImplementations/Rgba32.cs

@@ -318,6 +318,7 @@ public partial struct Rgba32 : IPixel<Rgba32>, IPackedVector<uint>
     /// Initializes the pixel instance from an <see cref="Rgb96"/> value.
     /// </summary>
     /// <param name="source">The <see cref="Rgb96"/> value.</param>
+    /// <returns>The pixel value as Rgba32.</returns>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Rgba32 FromRgb96(Rgb96 source)
         => new()

tests/ImageSharp.Benchmarks/Codecs/Exr/DecodeExr.cs

@@ -0,0 +1,68 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using BenchmarkDotNet.Attributes;
+
+using ImageMagick;
+using SixLabors.ImageSharp.Formats.Exr;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Tests;
+
+namespace SixLabors.ImageSharp.Benchmarks.Codecs;
+
+[MarkdownExporter]
+[HtmlExporter]
+[Config(typeof(Config.Short))]
+public class DecodeExr
+{
+    private Configuration configuration;
+
+    private byte[] imageBytes;
+
+    private string TestImageFullPath => Path.Combine(TestEnvironment.InputImagesDirectoryFullPath, this.TestImage);
+
+    [Params(TestImages.Exr.Benchamrk)]
+    public string TestImage { get; set; }
+
+    [GlobalSetup]
+    public void ReadImages()
+    {
+        this.configuration = Configuration.CreateDefaultInstance();
+        new ExrConfigurationModule().Configure(this.configuration);
+
+        this.imageBytes ??= File.ReadAllBytes(this.TestImageFullPath);
+    }
+
+    [Benchmark(Description = "Magick Exr")]
+    public int ExrImageMagick()
+    {
+        MagickReadSettings settings = new() { Format = MagickFormat.Exr };
+        using MemoryStream memoryStream = new(this.imageBytes);
+        using MagickImage image = new(memoryStream, settings);
+        return image.Width;
+    }
+
+    [Benchmark(Description = "ImageSharp Exr")]
+    public int ExrImageSharp()
+    {
+        using MemoryStream memoryStream = new(this.imageBytes);
+        using Image<Rgba32> image = Image.Load<Rgba32>(memoryStream);
+        return image.Height;
+    }
+
+    /* Results 27.03.2026
+        BenchmarkDotNet v0.15.8, Windows 11 (10.0.26200.8037/25H2/2025Update/HudsonValley2)
+        Intel Core i7-14700T 1.30GHz, 1 CPU, 28 logical and 20 physical cores
+        .NET SDK 10.0.201
+          [Host]     : .NET 8.0.25 (8.0.25, 8.0.2526.11203), X64 RyuJIT x86-64-v3
+          Job-VDWIGO : .NET 8.0.25 (8.0.25, 8.0.2526.11203), X64 RyuJIT x86-64-v3
+
+        Runtime=.NET 8.0  Arguments=/p:DebugType=portable  IterationCount=3
+        LaunchCount=1  WarmupCount=3
+
+        | Method           | TestImage                    | Mean     | Error    | StdDev   | Allocated |
+        |----------------- |----------------------------- |---------:|---------:|---------:|----------:|
+        | 'Magick Exr'     | Exr/Calliphora_benchmark.exr | 20.37 ms | 0.790 ms | 0.043 ms |  12.98 KB |
+        | 'ImageSharp Exr' | Exr/Calliphora_benchmark.exr | 45.68 ms | 4.999 ms | 0.274 ms |  34.09 KB |
+     */
+}

tests/ImageSharp.Tests/TestImages.cs

@@ -1383,6 +1383,7 @@ public static class TestImages
 
     public static class Exr
     {
+        public const string Benchamrk = "Exr/Calliphora_benchmark.exr";
         public const string Uncompressed = "Exr/Calliphora_uncompressed.exr";
         public const string UncompressedFloatRgb = "Exr/rgb_float32_uncompressed.exr";
         public const string UncompressedUintRgb = "Exr/rgb_uint32_uncompressed.exr";

tests/Images/Input/Exr/Calliphora_benchmark.exr

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e3368860692927e709365f2d37b92411068e77a0f23624ff57af6089ec69f357
+size 2592888