Initialize pixel type info from decoder.

src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs

@@ -208,7 +208,7 @@ internal sealed class BmpDecoderCore : IImageDecoderInternals
     public ImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken)
     {
         this.ReadImageHeaders(stream, out _, out _);
-        return new ImageInfo(new PixelTypeInfo(this.infoHeader.BitsPerPixel), new(this.infoHeader.Width, this.infoHeader.Height), this.metadata);
+        return new ImageInfo(new(this.infoHeader.Width, this.infoHeader.Height), this.metadata);
     }
 
     /// <summary>

src/ImageSharp/Formats/Gif/GifDecoderCore.cs

@@ -249,7 +249,6 @@ internal sealed class GifDecoderCore : IImageDecoderInternals
         }
 
         return new ImageInfo(
-            new PixelTypeInfo(this.logicalScreenDescriptor.BitsPerPixel),
             new(this.logicalScreenDescriptor.Width, this.logicalScreenDescriptor.Height),
             this.metadata,
             framesMetadata);

src/ImageSharp/Formats/ImageDecoder.cs

@@ -307,6 +307,7 @@ public abstract class ImageDecoder : IImageDecoder
         if (configuration.ImageFormatsManager.TryFindFormatByDecoder(this, out IImageFormat? format))
         {
             info.Metadata.DecodedImageFormat = format;
+            info.PixelType = info.Metadata.GetDecodedPixelTypeInfo();
 
             foreach (ImageFrameMetadata frame in info.FrameMetadataCollection)
             {

src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs

@@ -226,7 +226,7 @@ internal sealed class JpegDecoderCore : IRawJpegData, IImageDecoderInternals
         this.InitDerivedMetadataProperties();
 
         Size pixelSize = this.Frame.PixelSize;
-        return new ImageInfo(new PixelTypeInfo(this.Frame.BitsPerPixel), new(pixelSize.Width, pixelSize.Height), this.Metadata);
+        return new ImageInfo(new(pixelSize.Width, pixelSize.Height), this.Metadata);
     }
 
     /// <summary>

src/ImageSharp/Formats/Pbm/PbmDecoderCore.cs

@@ -69,7 +69,7 @@ internal sealed class PbmDecoderCore : IImageDecoderInternals
     {
         this.ProcessHeader(stream);
 
-        var image = new Image<TPixel>(this.configuration, this.pixelSize.Width, this.pixelSize.Height, this.metadata);
+        Image<TPixel> image = new(this.configuration, this.pixelSize.Width, this.pixelSize.Height, this.metadata);
 
         Buffer2D<TPixel> pixels = image.GetRootFramePixelBuffer();
 
@@ -86,10 +86,9 @@ internal sealed class PbmDecoderCore : IImageDecoderInternals
     public ImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken)
     {
         this.ProcessHeader(stream);
-
-        // BlackAndWhite pixels are encoded into a byte.
-        int bitsPerPixel = this.componentType == PbmComponentType.Short ? 16 : 8;
-        return new ImageInfo(new PixelTypeInfo(bitsPerPixel), new(this.pixelSize.Width, this.pixelSize.Height), this.metadata);
+        return new ImageInfo(
+            new(this.pixelSize.Width, this.pixelSize.Height),
+            this.metadata);
     }
 
     /// <summary>
@@ -97,6 +96,7 @@ internal sealed class PbmDecoderCore : IImageDecoderInternals
     /// </summary>
     /// <param name="stream">The input stream.</param>
     /// <exception cref="InvalidImageContentException">An EOF marker has been read before the image has been decoded.</exception>
+    [MemberNotNull(nameof(metadata))]
     private void ProcessHeader(BufferedReadStream stream)
     {
         Span<byte> buffer = stackalloc byte[2];

src/ImageSharp/Formats/Pbm/PbmMetadata.cs

@@ -97,20 +97,20 @@ public class PbmMetadata : IFormatMetadata<PbmMetadata>
                 colorType = PixelColorType.Binary;
                 info = PixelComponentInfo.Create(1, bpp, 1);
                 break;
-            case PbmColorType.Grayscale:
-                bpp = 8;
-                colorType = PixelColorType.Luminance;
-                info = PixelComponentInfo.Create(1, bpp, 8);
-                break;
             case PbmColorType.Rgb:
-                bpp = 24;
+                bpp = this.ComponentType == PbmComponentType.Short ? 48 : 24;
                 colorType = PixelColorType.RGB;
-                info = PixelComponentInfo.Create(3, bpp, 8, 8, 8);
+                info = this.ComponentType == PbmComponentType.Short
+                    ? PixelComponentInfo.Create(3, bpp, 16, 16, 16)
+                    : PixelComponentInfo.Create(3, bpp, 8, 8, 8);
                 break;
+            case PbmColorType.Grayscale:
             default:
-                bpp = 8;
+                bpp = this.ComponentType == PbmComponentType.Short ? 16 : 8;
                 colorType = PixelColorType.Luminance;
-                info = PixelComponentInfo.Create(1, bpp, 8);
+                info = this.ComponentType == PbmComponentType.Short
+                    ? PixelComponentInfo.Create(1, bpp, bpp)
+                    : PixelComponentInfo.Create(1, bpp, bpp);
                 break;
         }
 

src/ImageSharp/Formats/Png/PngDecoderCore.cs

@@ -515,7 +515,7 @@ internal sealed class PngDecoderCore : IImageDecoderInternals
             // Both PLTE and tRNS chunks, if present, have been read at this point as per spec.
             AssignColorPalette(this.palette, this.paletteAlpha, pngMetadata);
 
-            return new ImageInfo(new PixelTypeInfo(this.CalculateBitsPerPixel()), new(this.header.Width, this.header.Height), metadata);
+            return new ImageInfo(new(this.header.Width, this.header.Height), metadata);
         }
         finally
         {
@@ -680,29 +680,6 @@ internal sealed class PngDecoderCore : IImageDecoderInternals
         this.scanline = this.configuration.MemoryAllocator.Allocate<byte>(this.bytesPerScanline, AllocationOptions.Clean);
     }
 
-    /// <summary>
-    /// Calculates the correct number of bits per pixel for the given color type.
-    /// </summary>
-    /// <returns>The <see cref="int"/></returns>
-    private int CalculateBitsPerPixel()
-    {
-        switch (this.pngColorType)
-        {
-            case PngColorType.Grayscale:
-            case PngColorType.Palette:
-                return this.header.BitDepth;
-            case PngColorType.GrayscaleWithAlpha:
-                return this.header.BitDepth * 2;
-            case PngColorType.Rgb:
-                return this.header.BitDepth * 3;
-            case PngColorType.RgbWithAlpha:
-                return this.header.BitDepth * 4;
-            default:
-                PngThrowHelper.ThrowNotSupportedColor();
-                return -1;
-        }
-    }
-
     /// <summary>
     /// Calculates the correct number of bytes per pixel for the given color type.
     /// </summary>

src/ImageSharp/Formats/Png/PngMetadata.cs

@@ -176,9 +176,9 @@ public class PngMetadata : IFormatMetadata<PngMetadata>
                 break;
 
             case PngColorType.Grayscale:
-                bpp = 8;
+                bpp = (int)this.BitDepth;
                 colorType = PixelColorType.Luminance;
-                info = PixelComponentInfo.Create(1, bpp, 8);
+                info = PixelComponentInfo.Create(1, bpp, bpp);
                 break;
 
             case PngColorType.GrayscaleWithAlpha:
@@ -200,15 +200,15 @@ public class PngMetadata : IFormatMetadata<PngMetadata>
             case PngColorType.Rgb:
                 if (this.BitDepth == PngBitDepth.Bit16)
                 {
-                    bpp = 24;
+                    bpp = 48;
                     colorType = PixelColorType.RGB;
-                    info = PixelComponentInfo.Create(3, bpp, 8, 8, 8);
+                    info = PixelComponentInfo.Create(3, bpp, 16, 16, 16);
                     break;
                 }
 
-                bpp = 48;
+                bpp = 24;
                 colorType = PixelColorType.RGB;
-                info = PixelComponentInfo.Create(3, bpp, 16, 16, 16);
+                info = PixelComponentInfo.Create(3, bpp, 8, 8, 8);
                 break;
 
             case PngColorType.RgbWithAlpha:

src/ImageSharp/Formats/Qoi/QoiDecoderCore.cs

@@ -73,7 +73,7 @@ internal class QoiDecoderCore : IImageDecoderInternals
         qoiMetadata.Channels = this.header.Channels;
         qoiMetadata.ColorSpace = this.header.ColorSpace;
 
-        return new ImageInfo(pixelType, size, metadata);
+        return new ImageInfo(size, metadata);
     }
 
     /// <summary>

src/ImageSharp/Formats/Tga/TgaDecoderCore.cs

@@ -646,7 +646,6 @@ internal sealed class TgaDecoderCore : IImageDecoderInternals
     {
         this.ReadFileHeader(stream);
         return new ImageInfo(
-            new PixelTypeInfo(this.fileHeader.PixelDepth),
             new(this.fileHeader.Width, this.fileHeader.Height),
             this.metadata);
     }

src/ImageSharp/Formats/Tiff/TiffDecoderCore.cs

@@ -234,7 +234,7 @@ internal class TiffDecoderCore : IImageDecoderInternals
         int width = GetImageWidth(rootFrameExifProfile);
         int height = GetImageHeight(rootFrameExifProfile);
 
-        return new ImageInfo(new PixelTypeInfo((int)framesMetadata[0].GetTiffMetadata().BitsPerPixel), new(width, height), metadata, framesMetadata);
+        return new ImageInfo(new(width, height), metadata, framesMetadata);
     }
 
     /// <summary>

src/ImageSharp/Formats/Webp/WebpDecoderCore.cs

@@ -144,7 +144,6 @@ internal sealed class WebpDecoderCore : IImageDecoderInternals, IDisposable
         using (this.webImageInfo = this.ReadVp8Info(stream, metadata, true))
         {
             return new ImageInfo(
-                new PixelTypeInfo((int)this.webImageInfo.BitsPerPixel),
                 new Size((int)this.webImageInfo.Width, (int)this.webImageInfo.Height),
                 metadata);
         }

src/ImageSharp/ImageInfo.cs

@@ -14,40 +14,43 @@ public class ImageInfo
     /// <summary>
     /// Initializes a new instance of the <see cref="ImageInfo"/> class.
     /// </summary>
-    /// <param name="pixelType">The pixel type information.</param>
     /// <param name="size">The size of the image in px units.</param>
     /// <param name="metadata">The image metadata.</param>
     public ImageInfo(
-        PixelTypeInfo pixelType,
         Size size,
-        ImageMetadata? metadata)
-        : this(pixelType, size, metadata, null)
+        ImageMetadata metadata)
+        : this(size, metadata, null)
     {
     }
 
     /// <summary>
     /// Initializes a new instance of the <see cref="ImageInfo"/> class.
     /// </summary>
-    /// <param name="pixelType">The pixel type information.</param>
     /// <param name="size">The size of the image in px units.</param>
     /// <param name="metadata">The image metadata.</param>
     /// <param name="frameMetadataCollection">The collection of image frame metadata.</param>
     public ImageInfo(
-        PixelTypeInfo pixelType,
         Size size,
-        ImageMetadata? metadata,
+        ImageMetadata metadata,
         IReadOnlyList<ImageFrameMetadata>? frameMetadataCollection)
     {
-        this.PixelType = pixelType;
         this.Size = size;
-        this.Metadata = metadata ?? new ImageMetadata();
-        this.FrameMetadataCollection = frameMetadataCollection ?? Array.Empty<ImageFrameMetadata>();
+        this.Metadata = metadata;
+
+        // PixelTpe is normally set following decoding
+        // See ImageDecoder.SetDecoderFormat(Configuration configuration, ImageInfo info).
+        if (metadata.DecodedImageFormat is not null)
+        {
+            this.PixelType = metadata.GetDecodedPixelTypeInfo();
+        }
+
+        this.FrameMetadataCollection = frameMetadataCollection ?? [];
     }
 
     /// <summary>
     /// Gets information about the image pixels.
     /// </summary>
-    public PixelTypeInfo PixelType { get; }
+    public PixelTypeInfo PixelType { get; internal set; }
 
     /// <summary>
     /// Gets the image width in px units.

src/ImageSharp/Metadata/ImageMetadata.cs

@@ -7,6 +7,7 @@ using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 using SixLabors.ImageSharp.Metadata.Profiles.Icc;
 using SixLabors.ImageSharp.Metadata.Profiles.Iptc;
 using SixLabors.ImageSharp.Metadata.Profiles.Xmp;
+using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Metadata;
 
@@ -212,12 +213,25 @@ public sealed class ImageMetadata : IDeepCloneable<ImageMetadata>
     /// The <typeparamref name="TFormatMetadata"/>.
     /// </returns>
     public TFormatMetadata CloneFormatMetadata<TFormatMetadata>(IImageFormat<TFormatMetadata> key)
-        where TFormatMetadata : class, IFormatMetadata<TFormatMetadata>, new()
+        where TFormatMetadata : class, IFormatMetadata<TFormatMetadata>
         => ((IDeepCloneable<TFormatMetadata>)this.GetFormatMetadata(key)).DeepClone();
 
     /// <inheritdoc/>
     public ImageMetadata DeepClone() => new(this);
 
+    internal PixelTypeInfo GetDecodedPixelTypeInfo()
+    {
+        // None found. Check if we have a decoded format to convert from.
+        if (this.DecodedImageFormat is not null
+            && this.formatMetadata.TryGetValue(this.DecodedImageFormat, out IFormatMetadata? decodedMetadata))
+        {
+            return decodedMetadata.GetPixelTypeInfo();
+        }
+
+        // This should never happen.
+        return default;
+    }
+
     /// TODO: This should be called on save.
     /// <summary>
     /// Synchronizes the profiles with the current metadata.

tests/ImageSharp.Tests/Formats/Bmp/BmpDecoderTests.cs

@@ -4,6 +4,7 @@
 using Microsoft.DotNet.RemoteExecutor;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Bmp;
+using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.PixelFormats;
@@ -112,7 +113,7 @@ public class BmpDecoderTests
     {
         using Image<TPixel> image = provider.GetImage(BmpDecoder.Instance);
         image.DebugSave(provider);
-        image.CompareToOriginal(provider, new SystemDrawingReferenceDecoder());
+        image.CompareToOriginal(provider, new SystemDrawingReferenceDecoder(BmpFormat.Instance));
     }
 
     [Theory]
@@ -219,7 +220,7 @@ public class BmpDecoderTests
         image.DebugSave(provider);
         if (TestEnvironment.IsWindows)
         {
-            image.CompareToOriginal(provider, new SystemDrawingReferenceDecoder());
+            image.CompareToOriginal(provider, new SystemDrawingReferenceDecoder(BmpFormat.Instance));
         }
     }
 
@@ -232,7 +233,7 @@ public class BmpDecoderTests
         BmpDecoderOptions options = new() { RleSkippedPixelHandling = RleSkippedPixelHandling.FirstColorOfPalette };
         using Image<TPixel> image = provider.GetImage(BmpDecoder.Instance, options);
         image.DebugSave(provider);
-        image.CompareToOriginal(provider, new MagickReferenceDecoder());
+        image.CompareToOriginal(provider, MagickReferenceDecoder.Png);
     }
 
     [Theory]
@@ -251,7 +252,7 @@ public class BmpDecoderTests
         BmpDecoderOptions options = new() { RleSkippedPixelHandling = RleSkippedPixelHandling.FirstColorOfPalette };
         using Image<TPixel> image = provider.GetImage(BmpDecoder.Instance, options);
         image.DebugSave(provider);
-        image.CompareToOriginal(provider, new MagickReferenceDecoder());
+        image.CompareToOriginal(provider, MagickReferenceDecoder.Png);
     }
 
     [Theory]
@@ -298,7 +299,7 @@ public class BmpDecoderTests
     {
         using Image<TPixel> image = provider.GetImage(BmpDecoder.Instance);
         image.DebugSave(provider);
-        image.CompareToOriginal(provider, new MagickReferenceDecoder());
+        image.CompareToOriginal(provider, MagickReferenceDecoder.Png);
     }
 
     [Theory]
@@ -314,7 +315,7 @@ public class BmpDecoderTests
         // which should be remapped to 255 for RGBA32, but the magick decoder has a value of 191 set.
         // The total difference without the alpha channel is still: 0.0204%
         // Exporting the image as PNG with GIMP yields to the same result as the ImageSharp implementation.
-        image.CompareToOriginal(provider, ImageComparer.TolerantPercentage(6.1f), new MagickReferenceDecoder());
+        image.CompareToOriginal(provider, ImageComparer.TolerantPercentage(6.1f), MagickReferenceDecoder.Png);
     }
 
     [Theory]
@@ -327,7 +328,7 @@ public class BmpDecoderTests
         image.DebugSave(provider);
 
         // Do not validate. Reference files will fail validation.
-        image.CompareToOriginal(provider, new MagickReferenceDecoder(false));
+        image.CompareToOriginal(provider, new MagickReferenceDecoder(PngFormat.Instance, false));
     }
 
     [Theory]
@@ -347,7 +348,7 @@ public class BmpDecoderTests
     {
         using Image<TPixel> image = provider.GetImage(BmpDecoder.Instance);
         image.DebugSave(provider);
-        image.CompareToOriginal(provider, new MagickReferenceDecoder());
+        image.CompareToOriginal(provider, MagickReferenceDecoder.Png);
     }
 
     [Theory]
@@ -394,7 +395,7 @@ public class BmpDecoderTests
     {
         using Image<TPixel> image = provider.GetImage(BmpDecoder.Instance);
         image.DebugSave(provider);
-        image.CompareToOriginal(provider, new MagickReferenceDecoder());
+        image.CompareToOriginal(provider, MagickReferenceDecoder.Png);
     }
 
     [Theory]
@@ -404,7 +405,7 @@ public class BmpDecoderTests
     {
         using Image<TPixel> image = provider.GetImage(BmpDecoder.Instance);
         image.DebugSave(provider);
-        image.CompareToOriginal(provider, new MagickReferenceDecoder());
+        image.CompareToOriginal(provider, MagickReferenceDecoder.Png);
     }
 
     [Theory]

tests/ImageSharp.Tests/Formats/Bmp/BmpEncoderTests.cs

@@ -20,11 +20,11 @@ public class BmpEncoderTests
     private static BmpEncoder BmpEncoder => new();
 
     public static readonly TheoryData<BmpBitsPerPixel> BitsPerPixel =
-    new()
-    {
-        BmpBitsPerPixel.Bit24,
-        BmpBitsPerPixel.Bit32
-    };
+        new()
+        {
+            BmpBitsPerPixel.Bit24,
+            BmpBitsPerPixel.Bit32
+        };
 
     public static readonly TheoryData<string, int, int, PixelResolutionUnit> RatioFiles =
     new()
@@ -287,7 +287,7 @@ public class BmpEncoderTests
             provider,
             extension: "bmp",
             appendPixelTypeToFileName: false,
-            decoder: new MagickReferenceDecoder(false));
+            decoder: new MagickReferenceDecoder(BmpFormat.Instance, false));
     }
 
     [Theory]
@@ -318,7 +318,7 @@ public class BmpEncoderTests
             provider,
             extension: "bmp",
             appendPixelTypeToFileName: false,
-            decoder: new MagickReferenceDecoder(false));
+            decoder: new MagickReferenceDecoder(BmpFormat.Instance, false));
     }
 
     [Theory]
@@ -380,8 +380,8 @@ public class BmpEncoderTests
     {
         using Image<TPixel> image = provider.GetImage();
 
-        using var reencodedStream = new MemoryStream();
-        var encoder = new BmpEncoder
+        using MemoryStream reencodedStream = new();
+        BmpEncoder encoder = new()
         {
             BitsPerPixel = bitsPerPixel,
             SupportTransparency = false,

tests/ImageSharp.Tests/Formats/Jpg/JpegDecoderTests.cs

@@ -20,7 +20,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg;
 [ValidateDisposedMemoryAllocations]
 public partial class JpegDecoderTests
 {
-    private static MagickReferenceDecoder ReferenceDecoder => new();
+    private static MagickReferenceDecoder ReferenceDecoder => MagickReferenceDecoder.Jpeg;
 
     public const PixelTypes CommonNonDefaultPixelTypes = PixelTypes.Rgba32 | PixelTypes.Argb32 | PixelTypes.Bgr24 | PixelTypes.RgbaVector;
 

tests/ImageSharp.Tests/Formats/Png/PngDecoderTests.cs

@@ -485,7 +485,7 @@ public partial class PngDecoderTests
         if (compare)
         {
             // Magick cannot actually decode this image to compare.
-            image.CompareToOriginal(provider, new MagickReferenceDecoder(false));
+            image.CompareToOriginal(provider, new MagickReferenceDecoder(PngFormat.Instance, false));
         }
     }
 
@@ -552,7 +552,7 @@ public partial class PngDecoderTests
                 // We don't have another x-plat reference decoder that can be compared for this image.
                 if (TestEnvironment.IsWindows)
                 {
-                    image.CompareToOriginal(provider, ImageComparer.Exact, SystemDrawingReferenceDecoder.Instance);
+                    image.CompareToOriginal(provider, ImageComparer.Exact, SystemDrawingReferenceDecoder.Png);
                 }
             });
         Assert.Null(ex);
@@ -614,7 +614,7 @@ public partial class PngDecoderTests
                 // We don't have another x-plat reference decoder that can be compared for this image.
                 if (TestEnvironment.IsWindows)
                 {
-                    image.CompareToOriginal(provider, ImageComparer.Exact, SystemDrawingReferenceDecoder.Instance);
+                    image.CompareToOriginal(provider, ImageComparer.Exact, SystemDrawingReferenceDecoder.Png);
                 }
             });
         Assert.NotNull(ex);

tests/ImageSharp.Tests/Formats/Qoi/QoiEncoderTests.cs

@@ -24,7 +24,7 @@ public class QoiEncoderTests
     public static void Encode<TPixel>(TestImageProvider<TPixel> provider, QoiChannels channels, QoiColorSpace colorSpace)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        using Image<TPixel> image = provider.GetImage(new MagickReferenceDecoder());
+        using Image<TPixel> image = provider.GetImage(new MagickReferenceDecoder(QoiFormat.Instance));
         using MemoryStream stream = new();
         QoiEncoder encoder = new()
         {
@@ -34,7 +34,7 @@ public class QoiEncoderTests
         image.Save(stream, encoder);
         stream.Position = 0;
 
-        using Image<TPixel> encodedImage = (Image<TPixel>)Image.Load(stream);
+        using Image<TPixel> encodedImage = Image.Load<TPixel>(stream);
         QoiMetadata qoiMetadata = encodedImage.Metadata.GetQoiMetadata();
 
         ImageComparer.Exact.CompareImages(image, encodedImage);

tests/ImageSharp.Tests/Formats/Tga/TgaEncoderTests.cs

@@ -121,16 +121,14 @@ public class TgaEncoderTests
         where TPixel : unmanaged, IPixel<TPixel>
     {
         // The test image has alternating black and white pixels, which should make using always RLE data inefficient.
-        using (Image<TPixel> image = provider.GetImage())
-        {
-            var options = new TgaEncoder() { Compression = TgaCompression.RunLength };
-            using (var memStream = new MemoryStream())
-            {
-                image.Save(memStream, options);
-                byte[] imageBytes = memStream.ToArray();
-                Assert.Equal(expectedBytes, imageBytes.Length);
-            }
-        }
+        using Image<TPixel> image = provider.GetImage();
+        TgaEncoder options = new() { BitsPerPixel = TgaBitsPerPixel.Bit24, Compression = TgaCompression.RunLength };
+
+        using MemoryStream memStream = new();
+        image.Save(memStream, options);
+        byte[] imageBytes = memStream.ToArray();
+
+        Assert.Equal(expectedBytes, imageBytes.Length);
     }
 
     // Run length encoded pixels should not exceed row boundaries.

tests/ImageSharp.Tests/Formats/Tiff/TiffDecoderBaseTester.cs

@@ -12,7 +12,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff;
 
 public abstract class TiffDecoderBaseTester
 {
-    protected static MagickReferenceDecoder ReferenceDecoder => new();
+    protected static MagickReferenceDecoder ReferenceDecoder => new(TiffFormat.Instance);
 
     protected static void TestTiffDecoder<TPixel>(TestImageProvider<TPixel> provider, IImageDecoder referenceDecoder = null, bool useExactComparer = true, float compareTolerance = 0.001f)
         where TPixel : unmanaged, IPixel<TPixel>

tests/ImageSharp.Tests/Formats/Tiff/TiffEncoderBaseTester.cs

@@ -15,7 +15,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff;
 [Trait("Format", "Tiff")]
 public abstract class TiffEncoderBaseTester
 {
-    protected static readonly IImageDecoder ReferenceDecoder = new MagickReferenceDecoder();
+    protected static readonly IImageDecoder ReferenceDecoder = new MagickReferenceDecoder(TiffFormat.Instance);
 
     protected static void TestStripLength<TPixel>(
         TestImageProvider<TPixel> provider,
@@ -48,7 +48,6 @@ public abstract class TiffEncoderBaseTester
         Number[] stripByteCounts = exifProfileOutput.GetValue(ExifTag.StripByteCounts)?.Value;
         Assert.NotNull(stripByteCounts);
         Assert.True(stripByteCounts.Length > 1);
-        Assert.NotNull(outputMeta.BitsPerPixel);
 
         foreach (Number sz in stripByteCounts)
         {

tests/ImageSharp.Tests/Formats/WebP/WebpDecoderTests.cs

@@ -18,7 +18,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Webp;
 [ValidateDisposedMemoryAllocations]
 public class WebpDecoderTests
 {
-    private static MagickReferenceDecoder ReferenceDecoder => new();
+    private static MagickReferenceDecoder ReferenceDecoder => MagickReferenceDecoder.WebP;
 
     private static string TestImageLossyHorizontalFilterPath => Path.Combine(TestEnvironment.InputImagesDirectoryFullPath, Lossy.AlphaCompressedHorizontalFilter);
 

tests/ImageSharp.Tests/Formats/WebP/WebpEncoderTests.cs

@@ -169,10 +169,11 @@ public class WebpEncoderTests
     }
 
     [Theory]
-    [WithFile(Flag, PixelTypes.Rgba32, WebpFileFormatType.Lossy)] // If its not a webp input image, it should default to lossy.
+    [WithFile(TestImages.Jpeg.Baseline.Jpeg410, PixelTypes.Rgba32, WebpFileFormatType.Lossy)] // Input is lossy jpeg.
+    [WithFile(Flag, PixelTypes.Rgba32, WebpFileFormatType.Lossless)] // Input is lossless png.
     [WithFile(Lossless.NoTransform1, PixelTypes.Rgba32, WebpFileFormatType.Lossless)]
     [WithFile(Lossy.BikeWithExif, PixelTypes.Rgba32, WebpFileFormatType.Lossy)]
-    public void Encode_PreserveRatio<TPixel>(TestImageProvider<TPixel> provider, WebpFileFormatType expectedFormat)
+    public void Encode_PreserveEncodingType<TPixel>(TestImageProvider<TPixel> provider, WebpFileFormatType expectedFormat)
         where TPixel : unmanaged, IPixel<TPixel>
     {
         WebpEncoder options = new();
@@ -440,7 +441,7 @@ public class WebpEncoderTests
             "with_alpha",
             encoder,
             ImageComparer.Tolerant(0.04f),
-            referenceDecoder: new MagickReferenceDecoder());
+            referenceDecoder: MagickReferenceDecoder.WebP);
 
         int encodedBytes = File.ReadAllBytes(encodedFile).Length;
         Assert.True(encodedBytes <= expectedFileSize, $"encoded bytes are {encodedBytes} and should be smaller then expected file size of {expectedFileSize}");
@@ -468,7 +469,7 @@ public class WebpEncoderTests
             "with_alpha_compressed",
             encoder,
             ImageComparer.Tolerant(0.04f),
-            referenceDecoder: new MagickReferenceDecoder());
+            referenceDecoder: MagickReferenceDecoder.WebP);
 
         int encodedBytes = File.ReadAllBytes(encodedFile).Length;
         Assert.True(encodedBytes <= expectedFileSize, $"encoded bytes are {encodedBytes} and should be smaller then expected file size of {expectedFileSize}");

tests/ImageSharp.Tests/Formats/WebP/YuvConversionTests.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Webp;
 [Trait("Format", "Webp")]
 public class YuvConversionTests
 {
-    private static MagickReferenceDecoder ReferenceDecoder => new();
+    private static MagickReferenceDecoder ReferenceDecoder => MagickReferenceDecoder.WebP;
 
     private static string TestImageLossyFullPath => Path.Combine(TestEnvironment.InputImagesDirectoryFullPath, TestImages.Webp.Lossy.NoFilter06);
 

tests/ImageSharp.Tests/Image/ImageTests.ImageLoadTestBase.cs

@@ -4,6 +4,7 @@
 using Moq;
 
 using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.PixelFormats;
@@ -57,7 +58,7 @@ public partial class ImageTests
             // TODO: Remove all this mocking. It's too complicated and we can now use fakes.
             this.localStreamReturnImageRgba32 = new Image<Rgba32>(1, 1);
             this.localStreamReturnImageAgnostic = new Image<Bgra4444>(1, 1);
-            this.LocalImageInfo = new(new PixelTypeInfo(8), new(1, 1), new ImageMetadata());
+            this.LocalImageInfo = new(new(1, 1), new ImageMetadata() { DecodedImageFormat = PngFormat.Instance });
 
             this.localImageFormatMock = new Mock<IImageFormat>();
 

tests/ImageSharp.Tests/ImageInfoTests.cs

@@ -1,8 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Metadata;
-using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Tests;
 
@@ -15,12 +15,14 @@ public class ImageInfoTests
         const int height = 60;
         Size size = new(width, height);
         Rectangle rectangle = new(0, 0, width, height);
-        PixelTypeInfo pixelType = new(8);
-        ImageMetadata meta = new();
 
-        ImageInfo info = new(pixelType, size, meta);
+        // Initialize the metadata to match standard decoding behavior.
+        ImageMetadata meta = new() { DecodedImageFormat = PngFormat.Instance };
+        meta.GetPngMetadata();
 
-        Assert.Equal(pixelType, info.PixelType);
+        ImageInfo info = new(size, meta);
+
+        Assert.NotEqual(default, info.PixelType);
         Assert.Equal(width, info.Width);
         Assert.Equal(height, info.Height);
         Assert.Equal(size, info.Size);
@@ -35,13 +37,16 @@ public class ImageInfoTests
         const int height = 60;
         Size size = new(width, height);
         Rectangle rectangle = new(0, 0, width, height);
-        PixelTypeInfo pixelType = new(8);
-        ImageMetadata meta = new();
-        IReadOnlyList<ImageFrameMetadata> frameMetadata = new List<ImageFrameMetadata>() { new() };
 
-        ImageInfo info = new(pixelType, size, meta, frameMetadata);
+        // Initialize the metadata to match standard decoding behavior.
+        ImageMetadata meta = new() { DecodedImageFormat = PngFormat.Instance };
+        meta.GetPngMetadata();
+
+        IReadOnlyList<ImageFrameMetadata> frameMetadata = [new()];
+
+        ImageInfo info = new(size, meta, frameMetadata);
 
-        Assert.Equal(pixelType, info.PixelType);
+        Assert.NotEqual(default, info.PixelType);
         Assert.Equal(width, info.Width);
         Assert.Equal(height, info.Height);
         Assert.Equal(size, info.Size);

tests/ImageSharp.Tests/TestFormat.cs

@@ -7,6 +7,7 @@ using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.ImageSharp.Tests.TestUtilities;
+using SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs;
 
 namespace SixLabors.ImageSharp.Tests;
 
@@ -89,7 +90,7 @@ public class TestFormat : IImageFormatConfigurationModule, IImageFormat
         {
             if (!this.sampleImages.ContainsKey(typeof(TPixel)))
             {
-                this.sampleImages.Add(typeof(TPixel), new Image<TPixel>(1, 1));
+                this.sampleImages.Add(typeof(TPixel), ReferenceCodecUtilities.EnsureDecodedMetadata(new Image<TPixel>(1, 1), this));
             }
 
             return (Image<TPixel>)this.sampleImages[typeof(TPixel)];
@@ -202,11 +203,12 @@ public class TestFormat : IImageFormatConfigurationModule, IImageFormat
 
         protected override ImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
         {
-            Image<TestPixelForAgnosticDecode> image =
-                this.Decode<TestPixelForAgnosticDecode>(this.CreateDefaultSpecializedOptions(options), stream, cancellationToken);
-            ImageFrameCollection<TestPixelForAgnosticDecode> m = image.Frames;
-
-            return new(image.PixelType, image.Size, image.Metadata, new List<ImageFrameMetadata>(image.Frames.Select(x => x.Metadata)));
+            using Image<TestPixelForAgnosticDecode> image = this.Decode<TestPixelForAgnosticDecode>(this.CreateDefaultSpecializedOptions(options), stream, cancellationToken);
+            ImageMetadata metadata = image.Metadata;
+            return new(image.Size, metadata, new List<ImageFrameMetadata>(image.Frames.Select(x => x.Metadata)))
+            {
+                PixelType = metadata.GetDecodedPixelTypeInfo()
+            };
         }
 
         protected override TestDecoderOptions CreateDefaultSpecializedOptions(DecoderOptions options)

tests/ImageSharp.Tests/TestUtilities/ReferenceCodecs/MagickReferenceDecoder.cs

@@ -5,6 +5,11 @@ using System.Runtime.InteropServices;
 using ImageMagick;
 using ImageMagick.Formats;
 using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Formats.Bmp;
+using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.Formats.Tiff;
+using SixLabors.ImageSharp.Formats.Webp;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.PixelFormats;
@@ -13,19 +18,34 @@ namespace SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs;
 
 public class MagickReferenceDecoder : ImageDecoder
 {
+    private readonly IImageFormat imageFormat;
     private readonly bool validate;
 
-    public MagickReferenceDecoder()
-        : this(true)
+    public MagickReferenceDecoder(IImageFormat imageFormat)
+        : this(imageFormat, true)
     {
     }
 
-    public MagickReferenceDecoder(bool validate) => this.validate = validate;
+    public MagickReferenceDecoder(IImageFormat imageFormat, bool validate)
+    {
+        this.imageFormat = imageFormat;
+        this.validate = validate;
+    }
+
+    public static MagickReferenceDecoder Png { get; } = new MagickReferenceDecoder(PngFormat.Instance);
+
+    public static MagickReferenceDecoder Bmp { get; } = new MagickReferenceDecoder(BmpFormat.Instance);
+
+    public static MagickReferenceDecoder Jpeg { get; } = new MagickReferenceDecoder(JpegFormat.Instance);
 
-    public static MagickReferenceDecoder Instance { get; } = new();
+    public static MagickReferenceDecoder Tiff { get; } = new MagickReferenceDecoder(TiffFormat.Instance);
+
+    public static MagickReferenceDecoder WebP { get; } = new MagickReferenceDecoder(WebpFormat.Instance);
 
     protected override Image<TPixel> Decode<TPixel>(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
     {
+        ImageMetadata metadata = new();
+
         Configuration configuration = options.Configuration;
         BmpReadDefines bmpReadDefines = new()
         {
@@ -44,7 +64,7 @@ public class MagickReferenceDecoder : ImageDecoder
         settings.SetDefines(pngReadDefines);
 
         using MagickImageCollection magickImageCollection = new(stream, settings);
-        List<ImageFrame<TPixel>> framesList = new();
+        List<ImageFrame<TPixel>> framesList = [];
         foreach (IMagickImage<ushort> magicFrame in magickImageCollection)
         {
             ImageFrame<TPixel> frame = new(configuration, magicFrame.Width, magicFrame.Height);
@@ -61,6 +81,11 @@ public class MagickReferenceDecoder : ImageDecoder
             }
             else if (magicFrame.Depth is 16 or 14)
             {
+                if (this.imageFormat is PngFormat png)
+                {
+                    metadata.GetPngMetadata().BitDepth = PngBitDepth.Bit16;
+                }
+
                 ushort[] data = pixels.ToShortArray(PixelMapping.RGBA);
                 Span<byte> bytes = MemoryMarshal.Cast<ushort, byte>(data.AsSpan());
                 FromRgba64Bytes(configuration, bytes, framePixels);
@@ -71,7 +96,7 @@ public class MagickReferenceDecoder : ImageDecoder
             }
         }
 
-        return new Image<TPixel>(configuration, new ImageMetadata(), framesList);
+        return ReferenceCodecUtilities.EnsureDecodedMetadata<TPixel>(new(configuration, metadata, framesList), this.imageFormat);
     }
 
     protected override Image Decode(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
@@ -80,7 +105,11 @@ public class MagickReferenceDecoder : ImageDecoder
     protected override ImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
     {
         using Image<Rgba32> image = this.Decode<Rgba32>(options, stream, cancellationToken);
-        return new(image.PixelType, image.Size, image.Metadata, new List<ImageFrameMetadata>(image.Frames.Select(x => x.Metadata)));
+        ImageMetadata metadata = image.Metadata;
+        return new(image.Size, metadata, new List<ImageFrameMetadata>(image.Frames.Select(x => x.Metadata)))
+        {
+            PixelType = metadata.GetDecodedPixelTypeInfo()
+        };
     }
 
     private static void FromRgba32Bytes<TPixel>(Configuration configuration, Span<byte> rgbaBytes, IMemoryGroup<TPixel> destinationGroup)

tests/ImageSharp.Tests/TestUtilities/ReferenceCodecs/ReferenceCodecUtilities.cs

@@ -0,0 +1,94 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Formats.Bmp;
+using SixLabors.ImageSharp.Formats.Gif;
+using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Formats.Pbm;
+using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.Formats.Qoi;
+using SixLabors.ImageSharp.Formats.Tga;
+using SixLabors.ImageSharp.Formats.Tiff;
+using SixLabors.ImageSharp.Formats.Webp;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs;
+
+internal static class ReferenceCodecUtilities
+{
+    /// <summary>
+    /// Ensures that the metadata is properly initialized for reference and test encoders which cannot initialize
+    /// metadata in the same manner as our built in decoders.
+    /// </summary>
+    /// <typeparam name="TPixel">The type of pixel format.</typeparam>
+    /// <param name="image">The decoded image.</param>
+    /// <param name="format">The image format</param>
+    /// <exception cref="NotSupportedException">The format is unknown.</exception>
+    public static Image<TPixel> EnsureDecodedMetadata<TPixel>(Image<TPixel> image, IImageFormat format)
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        if (image.Metadata.DecodedImageFormat is null)
+        {
+            image.Metadata.DecodedImageFormat = format;
+        }
+
+        foreach (ImageFrame frame in image.Frames)
+        {
+            frame.Metadata.DecodedImageFormat = format;
+        }
+
+        switch (format)
+        {
+            case BmpFormat:
+                image.Metadata.GetBmpMetadata();
+                break;
+            case GifFormat:
+                image.Metadata.GetGifMetadata();
+                foreach (ImageFrame frame in image.Frames)
+                {
+                    frame.Metadata.GetGifMetadata();
+                }
+
+                break;
+            case JpegFormat:
+                image.Metadata.GetJpegMetadata();
+                break;
+            case PbmFormat:
+                image.Metadata.GetPbmMetadata();
+                break;
+            case PngFormat:
+                image.Metadata.GetPngMetadata();
+                foreach (ImageFrame frame in image.Frames)
+                {
+                    frame.Metadata.GetPngMetadata();
+                }
+
+                break;
+            case QoiFormat:
+                image.Metadata.GetQoiMetadata();
+                break;
+            case TgaFormat:
+                image.Metadata.GetTgaMetadata();
+                break;
+            case TiffFormat:
+                image.Metadata.GetTiffMetadata();
+                foreach (ImageFrame frame in image.Frames)
+                {
+                    frame.Metadata.GetTiffMetadata();
+                }
+
+                break;
+            case WebpFormat:
+                image.Metadata.GetWebpMetadata();
+                foreach (ImageFrame frame in image.Frames)
+                {
+                    frame.Metadata.GetWebpMetadata();
+                }
+
+                break;
+        }
+
+        return image;
+    }
+}

tests/ImageSharp.Tests/TestUtilities/ReferenceCodecs/SystemDrawingReferenceDecoder.cs

@@ -1,23 +1,35 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+#pragma warning disable CA1416 // Validate platform compatibility
 using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Formats.Bmp;
+using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.PixelFormats;
 using SDBitmap = System.Drawing.Bitmap;
-using SDImage = System.Drawing.Image;
 
 namespace SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs;
 
 public class SystemDrawingReferenceDecoder : ImageDecoder
 {
-    public static SystemDrawingReferenceDecoder Instance { get; } = new SystemDrawingReferenceDecoder();
+    private readonly IImageFormat imageFormat;
+
+    public SystemDrawingReferenceDecoder(IImageFormat imageFormat)
+        => this.imageFormat = imageFormat;
+
+    public static SystemDrawingReferenceDecoder Png { get; } = new SystemDrawingReferenceDecoder(PngFormat.Instance);
+
+    public static SystemDrawingReferenceDecoder Bmp { get; } = new SystemDrawingReferenceDecoder(BmpFormat.Instance);
 
     protected override ImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
     {
-        using SDBitmap sourceBitmap = new(stream);
-        PixelTypeInfo pixelType = new(SDImage.GetPixelFormatSize(sourceBitmap.PixelFormat));
-        return new ImageInfo(pixelType, new(sourceBitmap.Width, sourceBitmap.Height), new ImageMetadata());
+        using Image<Rgba32> image = this.Decode<Rgba32>(options, stream, cancellationToken);
+        ImageMetadata metadata = image.Metadata;
+        return new(image.Size, metadata, new List<ImageFrameMetadata>(image.Frames.Select(x => x.Metadata)))
+        {
+            PixelType = metadata.GetDecodedPixelTypeInfo()
+        };
     }
 
     protected override Image<TPixel> Decode<TPixel>(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
@@ -42,7 +54,9 @@ public class SystemDrawingReferenceDecoder : ImageDecoder
             g.DrawImage(sourceBitmap, 0, 0, sourceBitmap.Width, sourceBitmap.Height);
         }
 
-        return SystemDrawingBridge.From32bppArgbSystemDrawingBitmap<TPixel>(convertedBitmap);
+        return ReferenceCodecUtilities.EnsureDecodedMetadata(
+            SystemDrawingBridge.From32bppArgbSystemDrawingBitmap<TPixel>(convertedBitmap),
+            this.imageFormat);
     }
 
     protected override Image Decode(DecoderOptions options, Stream stream, CancellationToken cancellationToken)

tests/ImageSharp.Tests/TestUtilities/ReferenceCodecs/SystemDrawingReferenceEncoder.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+#pragma warning disable CA1416 // Validate platform compatibility
 using System.Drawing.Imaging;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.PixelFormats;

tests/ImageSharp.Tests/TestUtilities/TestEnvironment.Formats.cs

@@ -71,13 +71,13 @@ public static partial class TestEnvironment
         // Magick codecs should work on all platforms
         cfg.ConfigureCodecs(
             PngFormat.Instance,
-            MagickReferenceDecoder.Instance,
+            MagickReferenceDecoder.Png,
             pngEncoder,
             new PngImageFormatDetector());
 
         cfg.ConfigureCodecs(
             BmpFormat.Instance,
-            IsWindows ? SystemDrawingReferenceDecoder.Instance : MagickReferenceDecoder.Instance,
+            IsWindows ? SystemDrawingReferenceDecoder.Bmp : MagickReferenceDecoder.Bmp,
             bmpEncoder,
             new BmpImageFormatDetector());
 

tests/ImageSharp.Tests/TestUtilities/Tests/MagickReferenceCodecTests.cs

@@ -7,14 +7,13 @@ using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
 using SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs;
 using Xunit.Abstractions;
 
-// ReSharper disable InconsistentNaming
 namespace SixLabors.ImageSharp.Tests.TestUtilities.Tests;
 
 public class MagickReferenceCodecTests
 {
     public MagickReferenceCodecTests(ITestOutputHelper output) => this.Output = output;
 
-    private ITestOutputHelper Output { get; }
+    public ITestOutputHelper Output { get; }
 
     public const PixelTypes PixelTypesToTest32 = PixelTypes.Rgba32 | PixelTypes.Bgra32 | PixelTypes.Rgb24;
 
@@ -32,8 +31,8 @@ public class MagickReferenceCodecTests
     {
         string path = TestFile.GetInputFileFullPath(testImage);
 
-        var magickDecoder = new MagickReferenceDecoder();
-        var sdDecoder = new SystemDrawingReferenceDecoder();
+        MagickReferenceDecoder magickDecoder = MagickReferenceDecoder.Png;
+        SystemDrawingReferenceDecoder sdDecoder = SystemDrawingReferenceDecoder.Png;
 
         ImageComparer comparer = ImageComparer.Exact;
 
@@ -64,11 +63,11 @@ public class MagickReferenceCodecTests
     {
         string path = TestFile.GetInputFileFullPath(testImage);
 
-        var magickDecoder = new MagickReferenceDecoder();
-        var sdDecoder = new SystemDrawingReferenceDecoder();
+        MagickReferenceDecoder magickDecoder = MagickReferenceDecoder.Png;
+        SystemDrawingReferenceDecoder sdDecoder = SystemDrawingReferenceDecoder.Png;
 
-        // 1020 == 4 * 255 (Equivalent to manhattan distance of 1+1+1+1=4 in Rgba32 space)
-        var comparer = ImageComparer.TolerantPercentage(1, 1020);
+        // 1020 == 4 * 255 (Equivalent to Manhattan distance of 1+1+1+1=4 in Rgba32 space)
+        ImageComparer comparer = ImageComparer.TolerantPercentage(1, 1020);
         using FileStream mStream = File.OpenRead(path);
         using FileStream sdStream = File.OpenRead(path);
         using Image<TPixel> mImage = magickDecoder.Decode<TPixel>(DecoderOptions.Default, mStream);

tests/ImageSharp.Tests/TestUtilities/Tests/ReferenceDecoderBenchmarks.cs

@@ -47,7 +47,7 @@ public class ReferenceDecoderBenchmarks
     public void BenchmarkMagickPngDecoder<TPixel>(TestImageProvider<TPixel> provider)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        this.BenchmarkDecoderImpl(PngBenchmarkFiles, new MagickReferenceDecoder(), "Magick Decode Png");
+        this.BenchmarkDecoderImpl(PngBenchmarkFiles, MagickReferenceDecoder.Png, "Magick Decode Png");
     }
 
     [Theory(Skip = SkipBenchmarks)]
@@ -55,7 +55,7 @@ public class ReferenceDecoderBenchmarks
     public void BenchmarkSystemDrawingPngDecoder<TPixel>(TestImageProvider<TPixel> provider)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        this.BenchmarkDecoderImpl(PngBenchmarkFiles, new SystemDrawingReferenceDecoder(), "System.Drawing Decode Png");
+        this.BenchmarkDecoderImpl(PngBenchmarkFiles, SystemDrawingReferenceDecoder.Png, "System.Drawing Decode Png");
     }
 
     [Theory(Skip = SkipBenchmarks)]
@@ -63,7 +63,7 @@ public class ReferenceDecoderBenchmarks
     public void BenchmarkMagickBmpDecoder<TPixel>(TestImageProvider<TPixel> provider)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        this.BenchmarkDecoderImpl(BmpBenchmarkFiles, new MagickReferenceDecoder(), "Magick Decode Bmp");
+        this.BenchmarkDecoderImpl(BmpBenchmarkFiles, MagickReferenceDecoder.Bmp, "Magick Decode Bmp");
     }
 
     [Theory(Skip = SkipBenchmarks)]
@@ -71,7 +71,7 @@ public class ReferenceDecoderBenchmarks
     public void BenchmarkSystemDrawingBmpDecoder<TPixel>(TestImageProvider<TPixel> provider)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        this.BenchmarkDecoderImpl(BmpBenchmarkFiles, new SystemDrawingReferenceDecoder(), "System.Drawing Decode Bmp");
+        this.BenchmarkDecoderImpl(BmpBenchmarkFiles, SystemDrawingReferenceDecoder.Bmp, "System.Drawing Decode Bmp");
     }
 
     private void BenchmarkDecoderImpl(IEnumerable<string> testFiles, IImageDecoder decoder, string info, int times = DefaultExecutionCount)

tests/ImageSharp.Tests/TestUtilities/Tests/SystemDrawingReferenceCodecTests.cs

@@ -93,7 +93,7 @@ public class SystemDrawingReferenceCodecTests
     {
         string path = TestFile.GetInputFileFullPath(TestImages.Png.Splash);
         using FileStream stream = File.OpenRead(path);
-        using Image<TPixel> image = SystemDrawingReferenceDecoder.Instance.Decode<TPixel>(DecoderOptions.Default, stream);
+        using Image<TPixel> image = SystemDrawingReferenceDecoder.Png.Decode<TPixel>(DecoderOptions.Default, stream);
         image.DebugSave(dummyProvider);
     }
 

tests/ImageSharp.Tests/TestUtilities/Tests/TestImageProviderTests.cs

@@ -3,9 +3,11 @@
 
 using System.Collections.Concurrent;
 using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs;
 using Xunit.Abstractions;
 
 // ReSharper disable InconsistentNaming
@@ -25,7 +27,7 @@ public class TestImageProviderTests
         TestImageProvider<HalfVector4>.File(TestImages.Bmp.F)
     };
 
-    public static string[] AllBmpFiles = { TestImages.Bmp.F, TestImages.Bmp.Bit8 };
+    public static string[] AllBmpFiles = [TestImages.Bmp.F, TestImages.Bmp.Bit8];
 
     public TestImageProviderTests(ITestOutputHelper output) => this.Output = output;
 
@@ -80,9 +82,9 @@ public class TestImageProviderTests
         TestDecoder.DoTestThreadSafe(
             () =>
                 {
-                    string testName = nameof(this.GetImage_WithCustomParameterlessDecoder_ShouldUtilizeCache);
+                    const string testName = nameof(this.GetImage_WithCustomParameterlessDecoder_ShouldUtilizeCache);
 
-                    var decoder = new TestDecoder();
+                    TestDecoder decoder = new();
                     decoder.InitCaller(testName);
 
                     provider.GetImage(decoder);
@@ -335,7 +337,7 @@ public class TestImageProviderTests
     {
         using (provider.GetImage())
         {
-            var customConfiguration = Configuration.CreateDefaultInstance();
+            Configuration customConfiguration = Configuration.CreateDefaultInstance();
             provider.Configuration = customConfiguration;
 
             using Image<TPixel> image2 = provider.GetImage();
@@ -365,13 +367,17 @@ public class TestImageProviderTests
         protected override ImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
         {
             using Image<Rgba32> image = this.Decode<Rgba32>(this.CreateDefaultSpecializedOptions(options), stream, cancellationToken);
-            return new(image.PixelType, image.Size, image.Metadata, new List<ImageFrameMetadata>(image.Frames.Select(x => x.Metadata)));
+            ImageMetadata metadata = image.Metadata;
+            return new(image.Size, metadata, new List<ImageFrameMetadata>(image.Frames.Select(x => x.Metadata)))
+            {
+                PixelType = metadata.GetDecodedPixelTypeInfo()
+            };
         }
 
         protected override Image<TPixel> Decode<TPixel>(TestDecoderOptions options, Stream stream, CancellationToken cancellationToken)
         {
             InvocationCounts[this.callerName]++;
-            return new Image<TPixel>(42, 42);
+            return ReferenceCodecUtilities.EnsureDecodedMetadata(new Image<TPixel>(42, 42), PngFormat.Instance);
         }
 
         protected override Image Decode(TestDecoderOptions options, Stream stream, CancellationToken cancellationToken)
@@ -408,13 +414,17 @@ public class TestImageProviderTests
         protected override ImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
         {
             using Image<Rgba32> image = this.Decode<Rgba32>(this.CreateDefaultSpecializedOptions(options), stream, cancellationToken);
-            return new(image.PixelType, image.Size, image.Metadata, new List<ImageFrameMetadata>(image.Frames.Select(x => x.Metadata)));
+            ImageMetadata metadata = image.Metadata;
+            return new(image.Size, metadata, new List<ImageFrameMetadata>(image.Frames.Select(x => x.Metadata)))
+            {
+                PixelType = metadata.GetDecodedPixelTypeInfo()
+            };
         }
 
         protected override Image<TPixel> Decode<TPixel>(TestDecoderWithParametersOptions options, Stream stream, CancellationToken cancellationToken)
         {
             InvocationCounts[this.callerName]++;
-            return new Image<TPixel>(42, 42);
+            return ReferenceCodecUtilities.EnsureDecodedMetadata(new Image<TPixel>(42, 42), PngFormat.Instance);
         }
 
         protected override Image Decode(TestDecoderWithParametersOptions options, Stream stream, CancellationToken cancellationToken)