Merge branch 'main' into icc-color-conversion

src/ImageSharp/Advanced/AdvancedImageExtensions.cs

@@ -27,11 +27,11 @@ public static class AdvancedImageExtensions
         Guard.NotNull(filePath, nameof(filePath));
 
         string ext = Path.GetExtension(filePath);
-        if (!source.GetConfiguration().ImageFormatsManager.TryFindFormatByFileExtension(ext, out IImageFormat? format))
+        if (!source.Configuration.ImageFormatsManager.TryFindFormatByFileExtension(ext, out IImageFormat? format))
         {
             StringBuilder sb = new();
             sb = sb.AppendLine(CultureInfo.InvariantCulture, $"No encoder was found for extension '{ext}'. Registered encoders include:");
-            foreach (IImageFormat fmt in source.GetConfiguration().ImageFormats)
+            foreach (IImageFormat fmt in source.Configuration.ImageFormats)
             {
                 sb = sb.AppendFormat(CultureInfo.InvariantCulture, " - {0} : {1}{2}", fmt.Name, string.Join(", ", fmt.FileExtensions), Environment.NewLine);
             }
@@ -39,13 +39,13 @@ public static class AdvancedImageExtensions
             throw new UnknownImageFormatException(sb.ToString());
         }
 
-        IImageEncoder? encoder = source.GetConfiguration().ImageFormatsManager.GetEncoder(format);
+        IImageEncoder? encoder = source.Configuration.ImageFormatsManager.GetEncoder(format);
 
         if (encoder is null)
         {
             StringBuilder sb = new();
             sb = sb.AppendLine(CultureInfo.InvariantCulture, $"No encoder was found for extension '{ext}' using image format '{format.Name}'. Registered encoders include:");
-            foreach (KeyValuePair<IImageFormat, IImageEncoder> enc in source.GetConfiguration().ImageFormatsManager.ImageEncoders)
+            foreach (KeyValuePair<IImageFormat, IImageEncoder> enc in source.Configuration.ImageFormatsManager.ImageEncoders)
             {
                 sb = sb.AppendFormat(CultureInfo.InvariantCulture, " - {0} : {1}{2}", enc.Key, enc.Value.GetType().Name, Environment.NewLine);
             }
@@ -76,30 +76,6 @@ public static class AdvancedImageExtensions
     public static Task AcceptVisitorAsync(this Image source, IImageVisitorAsync visitor, CancellationToken cancellationToken = default)
         => source.AcceptAsync(visitor, cancellationToken);
 
-    /// <summary>
-    /// Gets the configuration for the image.
-    /// </summary>
-    /// <param name="source">The source image.</param>
-    /// <returns>Returns the configuration.</returns>
-    public static Configuration GetConfiguration(this Image source)
-        => GetConfiguration((IConfigurationProvider)source);
-
-    /// <summary>
-    /// Gets the configuration for the image frame.
-    /// </summary>
-    /// <param name="source">The source image.</param>
-    /// <returns>Returns the configuration.</returns>
-    public static Configuration GetConfiguration(this ImageFrame source)
-        => GetConfiguration((IConfigurationProvider)source);
-
-    /// <summary>
-    /// Gets the configuration.
-    /// </summary>
-    /// <param name="source">The source image</param>
-    /// <returns>Returns the bounds of the image</returns>
-    private static Configuration GetConfiguration(IConfigurationProvider source)
-        => source?.Configuration ?? Configuration.Default;
-
     /// <summary>
     /// Gets the representation of the pixels as a <see cref="IMemoryGroup{T}"/> containing the backing pixel data of the image
     /// stored in row major order, as a list of contiguous <see cref="Memory{T}"/> blocks in the source image's pixel format.
@@ -167,12 +143,4 @@ public static class AdvancedImageExtensions
 
         return source.Frames.RootFrame.PixelBuffer.GetSafeRowMemory(rowIndex);
     }
-
-    /// <summary>
-    /// Gets the <see cref="MemoryAllocator"/> assigned to 'source'.
-    /// </summary>
-    /// <param name="source">The source image.</param>
-    /// <returns>Returns the configuration.</returns>
-    internal static MemoryAllocator GetMemoryAllocator(this IConfigurationProvider source)
-        => GetConfiguration(source).MemoryAllocator;
 }

src/ImageSharp/Advanced/IConfigurationProvider.cs

@@ -6,7 +6,7 @@ namespace SixLabors.ImageSharp.Advanced;
 /// <summary>
 /// Defines the contract for objects that can provide access to configuration.
 /// </summary>
-internal interface IConfigurationProvider
+public interface IConfigurationProvider
 {
     /// <summary>
     /// Gets the configuration which allows altering default behaviour or extending the library.

src/ImageSharp/Color/Color.cs

@@ -251,7 +251,17 @@ public readonly partial struct Color : IEquatable<Color>
     /// </summary>
     /// <returns>A hexadecimal string representation of the value.</returns>
     [MethodImpl(InliningOptions.ShortMethod)]
-    public string ToHex() => this.data.ToRgba32().ToHex();
+    public string ToHex()
+    {
+        if (this.boxedHighPrecisionPixel is not null)
+        {
+            Rgba32 rgba = default;
+            this.boxedHighPrecisionPixel.ToRgba32(ref rgba);
+            return rgba.ToHex();
+        }
+
+        return this.data.ToRgba32().ToHex();
+    }
 
     /// <inheritdoc />
     public override string ToString() => this.ToHex();

src/ImageSharp/Compression/Zlib/ZlibInflateStream.cs

@@ -123,12 +123,12 @@ internal sealed class ZlibInflateStream : Stream
     /// <inheritdoc/>
     public override int Read(byte[] buffer, int offset, int count)
     {
-        if (this.currentDataRemaining == 0)
+        if (this.currentDataRemaining is 0)
         {
             // Last buffer was read in its entirety, let's make sure we don't actually have more in additional IDAT chunks.
             this.currentDataRemaining = this.getData();
 
-            if (this.currentDataRemaining == 0)
+            if (this.currentDataRemaining is 0)
             {
                 return 0;
             }
@@ -142,11 +142,11 @@ internal sealed class ZlibInflateStream : Stream
         // Keep reading data until we've reached the end of the stream or filled the buffer.
         int bytesRead = 0;
         offset += totalBytesRead;
-        while (this.currentDataRemaining == 0 && totalBytesRead < count)
+        while (this.currentDataRemaining is 0 && totalBytesRead < count)
         {
             this.currentDataRemaining = this.getData();
 
-            if (this.currentDataRemaining == 0)
+            if (this.currentDataRemaining is 0)
             {
                 return totalBytesRead;
             }
@@ -161,6 +161,11 @@ internal sealed class ZlibInflateStream : Stream
             bytesToRead = Math.Min(count - totalBytesRead, this.currentDataRemaining);
             this.currentDataRemaining -= bytesToRead;
             bytesRead = this.innerStream.Read(buffer, offset, bytesToRead);
+            if (bytesRead == 0)
+            {
+                return totalBytesRead;
+            }
+
             totalBytesRead += bytesRead;
         }
 
@@ -168,22 +173,13 @@ internal sealed class ZlibInflateStream : Stream
     }
 
     /// <inheritdoc/>
-    public override long Seek(long offset, SeekOrigin origin)
+    public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
-    {
-        throw new NotSupportedException();
-    }
 
     /// <inheritdoc/>
-    public override void SetLength(long value)
+    public override void SetLength(long value) => throw new NotSupportedException();
-    {
-        throw new NotSupportedException();
-    }
 
     /// <inheritdoc/>
-    public override void Write(byte[] buffer, int offset, int count)
+    public override void Write(byte[] buffer, int offset, int count) => throw new NotSupportedException();
-    {
-        throw new NotSupportedException();
-    }
 
     /// <inheritdoc/>
     protected override void Dispose(bool disposing)
@@ -246,22 +242,17 @@ internal sealed class ZlibInflateStream : Stream
                     // CINFO is not defined in this specification for CM not equal to 8.
                     throw new ImageFormatException($"Invalid window size for ZLIB header: cinfo={cinfo}");
                 }
-                else
+
-                {
+                return false;
-                    return false;
-                }
             }
         }
+        else if (isCriticalChunk)
+        {
+            throw new ImageFormatException($"Bad method for ZLIB header: cmf={cmf}");
+        }
         else
         {
-            if (isCriticalChunk)
+            return false;
-            {
-                throw new ImageFormatException($"Bad method for ZLIB header: cmf={cmf}");
-            }
-            else
-            {
-                return false;
-            }
         }
 
         // The preset dictionary.
@@ -270,7 +261,11 @@ internal sealed class ZlibInflateStream : Stream
         {
             // We don't need this for inflate so simply skip by the next four bytes.
             // https://tools.ietf.org/html/rfc1950#page-6
-            this.innerStream.Read(ChecksumBuffer, 0, 4);
+            if (this.innerStream.Read(ChecksumBuffer, 0, 4) != 4)
+            {
+                return false;
+            }
+
             this.currentDataRemaining -= 4;
         }
 

src/ImageSharp/Formats/Bmp/BmpEncoder.cs

@@ -32,7 +32,7 @@ public sealed class BmpEncoder : QuantizingImageEncoder
     /// <inheritdoc/>
     protected override void Encode<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
     {
-        BmpEncoderCore encoder = new(this, image.GetMemoryAllocator());
+        BmpEncoderCore encoder = new(this, image.Configuration.MemoryAllocator);
         encoder.Encode(image, stream, cancellationToken);
     }
 }

src/ImageSharp/Formats/Bmp/BmpEncoderCore.cs

@@ -119,7 +119,7 @@ internal sealed class BmpEncoderCore : IImageEncoderInternals
         Guard.NotNull(image, nameof(image));
         Guard.NotNull(stream, nameof(stream));
 
-        Configuration configuration = image.GetConfiguration();
+        Configuration configuration = image.Configuration;
         ImageMetadata metadata = image.Metadata;
         BmpMetadata bmpMetadata = metadata.GetBmpMetadata();
         this.bitsPerPixel ??= bmpMetadata.BitsPerPixel;

src/ImageSharp/Formats/Gif/GifEncoder.cs

@@ -18,7 +18,7 @@ public sealed class GifEncoder : QuantizingImageEncoder
     /// <inheritdoc/>
     protected override void Encode<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
     {
-        GifEncoderCore encoder = new(image.GetConfiguration(), this);
+        GifEncoderCore encoder = new(image.Configuration, this);
         encoder.Encode(image, stream, cancellationToken);
     }
 }

src/ImageSharp/Formats/Gif/GifEncoderCore.cs

@@ -189,7 +189,7 @@ internal sealed class GifEncoderCore : IImageEncoderInternals
         // This frame is reused to store de-duplicated pixel buffers.
         // This is more expensive memory-wise than de-duplicating indexed buffer but allows us to deduplicate
         // frames using both local and global palettes.
-        using ImageFrame<TPixel> encodingFrame = new(previousFrame.GetConfiguration(), previousFrame.Size());
+        using ImageFrame<TPixel> encodingFrame = new(previousFrame.Configuration, previousFrame.Size());
 
         for (int i = 1; i < image.Frames.Count; i++)
         {

src/ImageSharp/Formats/ImageDecoderUtilities.cs

@@ -50,7 +50,8 @@ internal static class ImageDecoderUtilities
         CancellationToken cancellationToken)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        using BufferedReadStream bufferedReadStream = new(configuration, stream, cancellationToken);
+        // Test may pass a BufferedReadStream in order to monitor EOF hits, if so, use the existing instance.
+        BufferedReadStream bufferedReadStream = stream as BufferedReadStream ?? new BufferedReadStream(configuration, stream, cancellationToken);
 
         try
         {
@@ -64,6 +65,13 @@ internal static class ImageDecoderUtilities
         {
             throw;
         }
+        finally
+        {
+            if (bufferedReadStream != stream)
+            {
+                bufferedReadStream.Dispose();
+            }
+        }
     }
 
     private static InvalidImageContentException DefaultLargeImageExceptionFactory(

src/ImageSharp/Formats/ImageEncoder.cs

@@ -42,7 +42,7 @@ public abstract class ImageEncoder : IImageEncoder
     private void EncodeWithSeekableStream<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        Configuration configuration = image.GetConfiguration();
+        Configuration configuration = image.Configuration;
         if (stream.CanSeek)
         {
             this.Encode(image, stream, cancellationToken);
@@ -59,7 +59,7 @@ public abstract class ImageEncoder : IImageEncoder
     private async Task EncodeWithSeekableStreamAsync<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        Configuration configuration = image.GetConfiguration();
+        Configuration configuration = image.Configuration;
         if (stream.CanSeek)
         {
             await DoEncodeAsync(stream).ConfigureAwait(false);

src/ImageSharp/Formats/ImageExtensions.Save.cs

@@ -59,7 +59,7 @@ public static partial class ImageExtensions
     public static void SaveAsBmp(this Image source, string path, BmpEncoder encoder) =>
         source.Save(
             path,
-            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(BmpFormat.Instance));
+            encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(BmpFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Bmp format.
@@ -73,7 +73,7 @@ public static partial class ImageExtensions
     public static Task SaveAsBmpAsync(this Image source, string path, BmpEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               path,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(BmpFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(BmpFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -106,7 +106,7 @@ public static partial class ImageExtensions
     public static void SaveAsBmp(this Image source, Stream stream, BmpEncoder encoder)
         => source.Save(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(BmpFormat.Instance));
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(BmpFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Bmp format.
@@ -120,7 +120,7 @@ public static partial class ImageExtensions
     public static Task SaveAsBmpAsync(this Image source, Stream stream, BmpEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(BmpFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(BmpFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -161,7 +161,7 @@ public static partial class ImageExtensions
     public static void SaveAsGif(this Image source, string path, GifEncoder encoder) =>
         source.Save(
             path,
-            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(GifFormat.Instance));
+            encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(GifFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Gif format.
@@ -175,7 +175,7 @@ public static partial class ImageExtensions
     public static Task SaveAsGifAsync(this Image source, string path, GifEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               path,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(GifFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(GifFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -208,7 +208,7 @@ public static partial class ImageExtensions
     public static void SaveAsGif(this Image source, Stream stream, GifEncoder encoder)
         => source.Save(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(GifFormat.Instance));
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(GifFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Gif format.
@@ -222,7 +222,7 @@ public static partial class ImageExtensions
     public static Task SaveAsGifAsync(this Image source, Stream stream, GifEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(GifFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(GifFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -263,7 +263,7 @@ public static partial class ImageExtensions
     public static void SaveAsJpeg(this Image source, string path, JpegEncoder encoder) =>
         source.Save(
             path,
-            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(JpegFormat.Instance));
+            encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(JpegFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Jpeg format.
@@ -277,7 +277,7 @@ public static partial class ImageExtensions
     public static Task SaveAsJpegAsync(this Image source, string path, JpegEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               path,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(JpegFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(JpegFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -310,7 +310,7 @@ public static partial class ImageExtensions
     public static void SaveAsJpeg(this Image source, Stream stream, JpegEncoder encoder)
         => source.Save(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(JpegFormat.Instance));
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(JpegFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Jpeg format.
@@ -324,7 +324,7 @@ public static partial class ImageExtensions
     public static Task SaveAsJpegAsync(this Image source, Stream stream, JpegEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(JpegFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(JpegFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -365,7 +365,7 @@ public static partial class ImageExtensions
     public static void SaveAsPbm(this Image source, string path, PbmEncoder encoder) =>
         source.Save(
             path,
-            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(PbmFormat.Instance));
+            encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(PbmFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Pbm format.
@@ -379,7 +379,7 @@ public static partial class ImageExtensions
     public static Task SaveAsPbmAsync(this Image source, string path, PbmEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               path,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(PbmFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(PbmFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -412,7 +412,7 @@ public static partial class ImageExtensions
     public static void SaveAsPbm(this Image source, Stream stream, PbmEncoder encoder)
         => source.Save(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(PbmFormat.Instance));
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(PbmFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Pbm format.
@@ -426,7 +426,7 @@ public static partial class ImageExtensions
     public static Task SaveAsPbmAsync(this Image source, Stream stream, PbmEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(PbmFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(PbmFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -467,7 +467,7 @@ public static partial class ImageExtensions
     public static void SaveAsPng(this Image source, string path, PngEncoder encoder) =>
         source.Save(
             path,
-            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(PngFormat.Instance));
+            encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(PngFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Png format.
@@ -481,7 +481,7 @@ public static partial class ImageExtensions
     public static Task SaveAsPngAsync(this Image source, string path, PngEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               path,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(PngFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(PngFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -514,7 +514,7 @@ public static partial class ImageExtensions
     public static void SaveAsPng(this Image source, Stream stream, PngEncoder encoder)
         => source.Save(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(PngFormat.Instance));
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(PngFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Png format.
@@ -528,7 +528,7 @@ public static partial class ImageExtensions
     public static Task SaveAsPngAsync(this Image source, Stream stream, PngEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(PngFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(PngFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -569,7 +569,7 @@ public static partial class ImageExtensions
     public static void SaveAsQoi(this Image source, string path, QoiEncoder encoder) =>
         source.Save(
             path,
-            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(QoiFormat.Instance));
+            encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(QoiFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Qoi format.
@@ -583,7 +583,7 @@ public static partial class ImageExtensions
     public static Task SaveAsQoiAsync(this Image source, string path, QoiEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               path,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(QoiFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(QoiFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -616,7 +616,7 @@ public static partial class ImageExtensions
     public static void SaveAsQoi(this Image source, Stream stream, QoiEncoder encoder)
         => source.Save(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(QoiFormat.Instance));
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(QoiFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Qoi format.
@@ -630,7 +630,7 @@ public static partial class ImageExtensions
     public static Task SaveAsQoiAsync(this Image source, Stream stream, QoiEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(QoiFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(QoiFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -671,7 +671,7 @@ public static partial class ImageExtensions
     public static void SaveAsTga(this Image source, string path, TgaEncoder encoder) =>
         source.Save(
             path,
-            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(TgaFormat.Instance));
+            encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(TgaFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Tga format.
@@ -685,7 +685,7 @@ public static partial class ImageExtensions
     public static Task SaveAsTgaAsync(this Image source, string path, TgaEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               path,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(TgaFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(TgaFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -718,7 +718,7 @@ public static partial class ImageExtensions
     public static void SaveAsTga(this Image source, Stream stream, TgaEncoder encoder)
         => source.Save(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(TgaFormat.Instance));
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(TgaFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Tga format.
@@ -732,7 +732,7 @@ public static partial class ImageExtensions
     public static Task SaveAsTgaAsync(this Image source, Stream stream, TgaEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(TgaFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(TgaFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -773,7 +773,7 @@ public static partial class ImageExtensions
     public static void SaveAsTiff(this Image source, string path, TiffEncoder encoder) =>
         source.Save(
             path,
-            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(TiffFormat.Instance));
+            encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(TiffFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Tiff format.
@@ -787,7 +787,7 @@ public static partial class ImageExtensions
     public static Task SaveAsTiffAsync(this Image source, string path, TiffEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               path,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(TiffFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(TiffFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -820,7 +820,7 @@ public static partial class ImageExtensions
     public static void SaveAsTiff(this Image source, Stream stream, TiffEncoder encoder)
         => source.Save(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(TiffFormat.Instance));
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(TiffFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Tiff format.
@@ -834,7 +834,7 @@ public static partial class ImageExtensions
     public static Task SaveAsTiffAsync(this Image source, Stream stream, TiffEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(TiffFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(TiffFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -875,7 +875,7 @@ public static partial class ImageExtensions
     public static void SaveAsWebp(this Image source, string path, WebpEncoder encoder) =>
         source.Save(
             path,
-            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(WebpFormat.Instance));
+            encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(WebpFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Webp format.
@@ -889,7 +889,7 @@ public static partial class ImageExtensions
     public static Task SaveAsWebpAsync(this Image source, string path, WebpEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               path,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(WebpFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(WebpFormat.Instance),
               cancellationToken);
 
     /// <summary>
@@ -922,7 +922,7 @@ public static partial class ImageExtensions
     public static void SaveAsWebp(this Image source, Stream stream, WebpEncoder encoder)
         => source.Save(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(WebpFormat.Instance));
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(WebpFormat.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the Webp format.
@@ -936,7 +936,7 @@ public static partial class ImageExtensions
     public static Task SaveAsWebpAsync(this Image source, Stream stream, WebpEncoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(WebpFormat.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(WebpFormat.Instance),
               cancellationToken);
 
 }

src/ImageSharp/Formats/ImageExtensions.Save.tt

@@ -78,7 +78,7 @@ public static partial class ImageExtensions
     public static void SaveAs<#= fmt #>(this Image source, string path, <#= fmt #>Encoder encoder) =>
         source.Save(
             path,
-            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(<#= fmt #>Format.Instance));
+            encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(<#= fmt #>Format.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the <#= fmt #> format.
@@ -92,7 +92,7 @@ public static partial class ImageExtensions
     public static Task SaveAs<#= fmt #>Async(this Image source, string path, <#= fmt #>Encoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               path,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(<#= fmt #>Format.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(<#= fmt #>Format.Instance),
               cancellationToken);
 
     /// <summary>
@@ -125,7 +125,7 @@ public static partial class ImageExtensions
     public static void SaveAs<#= fmt #>(this Image source, Stream stream, <#= fmt #>Encoder encoder)
         => source.Save(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(<#= fmt #>Format.Instance));
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(<#= fmt #>Format.Instance));
 
     /// <summary>
     /// Saves the image to the given stream with the <#= fmt #> format.
@@ -139,7 +139,7 @@ public static partial class ImageExtensions
     public static Task SaveAs<#= fmt #>Async(this Image source, Stream stream, <#= fmt #>Encoder encoder, CancellationToken cancellationToken = default)
         => source.SaveAsync(
               stream,
-              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(<#= fmt #>Format.Instance),
+              encoder ?? source.Configuration.ImageFormatsManager.GetEncoder(<#= fmt #>Format.Instance),
               cancellationToken);
 
 <#

src/ImageSharp/Formats/Jpeg/Components/Encoder/JpegFrame.cs

@@ -20,7 +20,7 @@ internal sealed class JpegFrame : IDisposable
         this.PixelWidth = image.Width;
         this.PixelHeight = image.Height;
 
-        MemoryAllocator allocator = image.GetConfiguration().MemoryAllocator;
+        MemoryAllocator allocator = image.Configuration.MemoryAllocator;
 
         JpegComponentConfig[] componentConfigs = frameConfig.Components;
         this.Components = new Component[componentConfigs.Length];

src/ImageSharp/Formats/Jpeg/Components/Encoder/SpectralConverter{TPixel}.cs

@@ -32,7 +32,7 @@ internal class SpectralConverter<TPixel> : SpectralConverter, IDisposable
 
     public SpectralConverter(JpegFrame frame, Image<TPixel> image, Block8x8F[] dequantTables)
     {
-        MemoryAllocator allocator = image.GetConfiguration().MemoryAllocator;
+        MemoryAllocator allocator = image.Configuration.MemoryAllocator;
 
         // iteration data
         int majorBlockWidth = frame.Components.Max((component) => component.SizeInBlocks.Width);

src/ImageSharp/Formats/Pbm/BinaryDecoder.cs

@@ -71,7 +71,11 @@ internal class BinaryDecoder
 
         for (int y = 0; y < height; y++)
         {
-            stream.Read(rowSpan);
+            if (stream.Read(rowSpan) < rowSpan.Length)
+            {
+                return;
+            }
+
             Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
             PixelOperations<TPixel>.Instance.FromL8Bytes(
                 configuration,
@@ -93,7 +97,11 @@ internal class BinaryDecoder
 
         for (int y = 0; y < height; y++)
         {
-            stream.Read(rowSpan);
+            if (stream.Read(rowSpan) < rowSpan.Length)
+            {
+                return;
+            }
+
             Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
             PixelOperations<TPixel>.Instance.FromL16Bytes(
                 configuration,
@@ -115,7 +123,11 @@ internal class BinaryDecoder
 
         for (int y = 0; y < height; y++)
         {
-            stream.Read(rowSpan);
+            if (stream.Read(rowSpan) < rowSpan.Length)
+            {
+                return;
+            }
+
             Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
             PixelOperations<TPixel>.Instance.FromRgb24Bytes(
                 configuration,
@@ -137,7 +149,11 @@ internal class BinaryDecoder
 
         for (int y = 0; y < height; y++)
         {
-            stream.Read(rowSpan);
+            if (stream.Read(rowSpan) < rowSpan.Length)
+            {
+                return;
+            }
+
             Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
             PixelOperations<TPixel>.Instance.FromRgb48Bytes(
                 configuration,
@@ -161,6 +177,11 @@ internal class BinaryDecoder
             for (int x = 0; x < width;)
             {
                 int raw = stream.ReadByte();
+                if (raw < 0)
+                {
+                    return;
+                }
+
                 int stopBit = Math.Min(8, width - x);
                 for (int bit = 0; bit < stopBit; bit++)
                 {

src/ImageSharp/Formats/Pbm/BufferedReadStreamExtensions.cs

@@ -11,14 +11,20 @@ namespace SixLabors.ImageSharp.Formats.Pbm;
 internal static class BufferedReadStreamExtensions
 {
     /// <summary>
-    /// Skip over any whitespace or any comments.
+    /// Skip over any whitespace or any comments and signal if EOF has been reached.
     /// </summary>
-    public static void SkipWhitespaceAndComments(this BufferedReadStream stream)
+    /// <param name="stream">The buffered read stream.</param>
+    /// <returns><see langword="false"/> if EOF has been reached while reading the stream; see langword="true"/> otherwise.</returns>
+    public static bool SkipWhitespaceAndComments(this BufferedReadStream stream)
     {
         bool isWhitespace;
         do
         {
             int val = stream.ReadByte();
+            if (val < 0)
+            {
+                return false;
+            }
 
             // Comments start with '#' and end at the next new-line.
             if (val == 0x23)
@@ -27,8 +33,12 @@ internal static class BufferedReadStreamExtensions
                 do
                 {
                     innerValue = stream.ReadByte();
+                    if (innerValue < 0)
+                    {
+                        return false;
+                    }
                 }
-                while (innerValue is not 0x0a and not -0x1);
+                while (innerValue is not 0x0a);
 
                 // Continue searching for whitespace.
                 val = innerValue;
@@ -38,18 +48,31 @@ internal static class BufferedReadStreamExtensions
         }
         while (isWhitespace);
         stream.Seek(-1, SeekOrigin.Current);
+        return true;
     }
 
     /// <summary>
-    /// Read a decimal text value.
+    /// Read a decimal text value and signal if EOF has been reached.
     /// </summary>
-    /// <returns>The integer value of the decimal.</returns>
+    /// <param name="stream">The buffered read stream.</param>
-    public static int ReadDecimal(this BufferedReadStream stream)
+    /// <param name="value">The read value.</param>
+    /// <returns><see langword="false"/> if EOF has been reached while reading the stream; <see langword="true"/> otherwise.</returns>
+    /// <remarks>
+    /// A 'false' return value doesn't mean that the parsing has been failed, since it's possible to reach EOF while reading the last decimal in the file.
+    /// It's up to the call site to handle such a situation.
+    /// </remarks>
+    public static bool ReadDecimal(this BufferedReadStream stream, out int value)
     {
-        int value = 0;
+        value = 0;
         while (true)
         {
-            int current = stream.ReadByte() - 0x30;
+            int current = stream.ReadByte();
+            if (current < 0)
+            {
+                return false;
+            }
+
+            current -= 0x30;
             if ((uint)current > 9)
             {
                 break;
@@ -58,6 +81,6 @@ internal static class BufferedReadStreamExtensions
             value = (value * 10) + current;
         }
 
-        return value;
+        return true;
     }
 }

src/ImageSharp/Formats/Pbm/PbmDecoderCore.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
 using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata;
@@ -95,6 +96,7 @@ internal sealed class PbmDecoderCore : IImageDecoderInternals
     /// Processes the ppm header.
     /// </summary>
     /// <param name="stream">The input stream.</param>
+    /// <exception cref="InvalidImageContentException">An EOF marker has been read before the image has been decoded.</exception>
     private void ProcessHeader(BufferedReadStream stream)
     {
         Span<byte> buffer = stackalloc byte[2];
@@ -144,14 +146,22 @@ internal sealed class PbmDecoderCore : IImageDecoderInternals
                 throw new InvalidImageContentException("Unknown of not implemented image type encountered.");
         }
 
-        stream.SkipWhitespaceAndComments();
+        if (!stream.SkipWhitespaceAndComments() ||
-        int width = stream.ReadDecimal();
+            !stream.ReadDecimal(out int width) ||
-        stream.SkipWhitespaceAndComments();
+            !stream.SkipWhitespaceAndComments() ||
-        int height = stream.ReadDecimal();
+            !stream.ReadDecimal(out int height) ||
-        stream.SkipWhitespaceAndComments();
+            !stream.SkipWhitespaceAndComments())
+        {
+            ThrowPrematureEof();
+        }
+
         if (this.colorType != PbmColorType.BlackAndWhite)
         {
-            this.maxPixelValue = stream.ReadDecimal();
+            if (!stream.ReadDecimal(out this.maxPixelValue))
+            {
+                ThrowPrematureEof();
+            }
+
             if (this.maxPixelValue > 255)
             {
                 this.componentType = PbmComponentType.Short;
@@ -174,6 +184,9 @@ internal sealed class PbmDecoderCore : IImageDecoderInternals
         meta.Encoding = this.encoding;
         meta.ColorType = this.colorType;
         meta.ComponentType = this.componentType;
+
+        [DoesNotReturn]
+        static void ThrowPrematureEof() => throw new InvalidImageContentException("Reached EOF while reading the header.");
     }
 
     private void ProcessPixels<TPixel>(BufferedReadStream stream, Buffer2D<TPixel> pixels)

src/ImageSharp/Formats/Pbm/PbmEncoder.cs

@@ -49,7 +49,7 @@ public sealed class PbmEncoder : ImageEncoder
     /// <inheritdoc/>
     protected override void Encode<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
     {
-        PbmEncoderCore encoder = new(image.GetConfiguration(), this);
+        PbmEncoderCore encoder = new(image.Configuration, this);
         encoder.Encode(image, stream, cancellationToken);
     }
 }

src/ImageSharp/Formats/Pbm/PbmEncoderCore.cs

@@ -78,7 +78,7 @@ internal sealed class PbmEncoderCore : IImageEncoderInternals
     private void SanitizeAndSetEncoderOptions<TPixel>(Image<TPixel> image)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        this.configuration = image.GetConfiguration();
+        this.configuration = image.Configuration;
         PbmMetadata metadata = image.Metadata.GetPbmMetadata();
         this.encoding = this.encoder.Encoding ?? metadata.Encoding;
         this.colorType = this.encoder.ColorType ?? metadata.ColorType;

src/ImageSharp/Formats/Pbm/PlainDecoder.cs

@@ -65,13 +65,18 @@ internal class PlainDecoder
         using IMemoryOwner<L8> row = allocator.Allocate<L8>(width);
         Span<L8> rowSpan = row.GetSpan();
 
+        bool eofReached = false;
         for (int y = 0; y < height; y++)
         {
             for (int x = 0; x < width; x++)
             {
-                byte value = (byte)stream.ReadDecimal();
+                stream.ReadDecimal(out int value);
-                stream.SkipWhitespaceAndComments();
+                rowSpan[x] = new L8((byte)value);
-                rowSpan[x] = new L8(value);
+                eofReached = !stream.SkipWhitespaceAndComments();
+                if (eofReached)
+                {
+                    break;
+                }
             }
 
             Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
@@ -79,6 +84,11 @@ internal class PlainDecoder
                 configuration,
                 rowSpan,
                 pixelSpan);
+
+            if (eofReached)
+            {
+                return;
+            }
         }
     }
 
@@ -91,13 +101,18 @@ internal class PlainDecoder
         using IMemoryOwner<L16> row = allocator.Allocate<L16>(width);
         Span<L16> rowSpan = row.GetSpan();
 
+        bool eofReached = false;
         for (int y = 0; y < height; y++)
         {
             for (int x = 0; x < width; x++)
             {
-                ushort value = (ushort)stream.ReadDecimal();
+                stream.ReadDecimal(out int value);
-                stream.SkipWhitespaceAndComments();
+                rowSpan[x] = new L16((ushort)value);
-                rowSpan[x] = new L16(value);
+                eofReached = !stream.SkipWhitespaceAndComments();
+                if (eofReached)
+                {
+                    break;
+                }
             }
 
             Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
@@ -105,6 +120,11 @@ internal class PlainDecoder
                 configuration,
                 rowSpan,
                 pixelSpan);
+
+            if (eofReached)
+            {
+                return;
+            }
         }
     }
 
@@ -117,17 +137,29 @@ internal class PlainDecoder
         using IMemoryOwner<Rgb24> row = allocator.Allocate<Rgb24>(width);
         Span<Rgb24> rowSpan = row.GetSpan();
 
+        bool eofReached = false;
         for (int y = 0; y < height; y++)
         {
             for (int x = 0; x < width; x++)
             {
-                byte red = (byte)stream.ReadDecimal();
+                if (!stream.ReadDecimal(out int red) ||
-                stream.SkipWhitespaceAndComments();
+                    !stream.SkipWhitespaceAndComments() ||
-                byte green = (byte)stream.ReadDecimal();
+                    !stream.ReadDecimal(out int green) ||
-                stream.SkipWhitespaceAndComments();
+                    !stream.SkipWhitespaceAndComments())
-                byte blue = (byte)stream.ReadDecimal();
+                {
-                stream.SkipWhitespaceAndComments();
+                    // Reached EOF before reading a full RGB value
-                rowSpan[x] = new Rgb24(red, green, blue);
+                    eofReached = true;
+                    break;
+                }
+
+                stream.ReadDecimal(out int blue);
+
+                rowSpan[x] = new Rgb24((byte)red, (byte)green, (byte)blue);
+                eofReached = !stream.SkipWhitespaceAndComments();
+                if (eofReached)
+                {
+                    break;
+                }
             }
 
             Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
@@ -135,6 +167,11 @@ internal class PlainDecoder
                 configuration,
                 rowSpan,
                 pixelSpan);
+
+            if (eofReached)
+            {
+                return;
+            }
         }
     }
 
@@ -147,17 +184,29 @@ internal class PlainDecoder
         using IMemoryOwner<Rgb48> row = allocator.Allocate<Rgb48>(width);
         Span<Rgb48> rowSpan = row.GetSpan();
 
+        bool eofReached = false;
         for (int y = 0; y < height; y++)
         {
             for (int x = 0; x < width; x++)
             {
-                ushort red = (ushort)stream.ReadDecimal();
+                if (!stream.ReadDecimal(out int red) ||
-                stream.SkipWhitespaceAndComments();
+                    !stream.SkipWhitespaceAndComments() ||
-                ushort green = (ushort)stream.ReadDecimal();
+                    !stream.ReadDecimal(out int green) ||
-                stream.SkipWhitespaceAndComments();
+                    !stream.SkipWhitespaceAndComments())
-                ushort blue = (ushort)stream.ReadDecimal();
+                {
-                stream.SkipWhitespaceAndComments();
+                    // Reached EOF before reading a full RGB value
-                rowSpan[x] = new Rgb48(red, green, blue);
+                    eofReached = true;
+                    break;
+                }
+
+                stream.ReadDecimal(out int blue);
+
+                rowSpan[x] = new Rgb48((ushort)red, (ushort)green, (ushort)blue);
+                eofReached = !stream.SkipWhitespaceAndComments();
+                if (eofReached)
+                {
+                    break;
+                }
             }
 
             Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
@@ -165,6 +214,11 @@ internal class PlainDecoder
                 configuration,
                 rowSpan,
                 pixelSpan);
+
+            if (eofReached)
+            {
+                return;
+            }
         }
     }
 
@@ -177,13 +231,19 @@ internal class PlainDecoder
         using IMemoryOwner<L8> row = allocator.Allocate<L8>(width);
         Span<L8> rowSpan = row.GetSpan();
 
+        bool eofReached = false;
         for (int y = 0; y < height; y++)
         {
             for (int x = 0; x < width; x++)
             {
-                int value = stream.ReadDecimal();
+                stream.ReadDecimal(out int value);
-                stream.SkipWhitespaceAndComments();
+
                 rowSpan[x] = value == 0 ? White : Black;
+                eofReached = !stream.SkipWhitespaceAndComments();
+                if (eofReached)
+                {
+                    break;
+                }
             }
 
             Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
@@ -191,6 +251,11 @@ internal class PlainDecoder
                 configuration,
                 rowSpan,
                 pixelSpan);
+
+            if (eofReached)
+            {
+                return;
+            }
         }
     }
 }

src/ImageSharp/Formats/Png/Chunks/AnimationControl.cs

@@ -0,0 +1,47 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using System.Buffers.Binary;
+
+namespace SixLabors.ImageSharp.Formats.Png.Chunks;
+
+internal readonly struct AnimationControl
+{
+    public const int Size = 8;
+
+    public AnimationControl(int numberFrames, int numberPlays)
+    {
+        this.NumberFrames = numberFrames;
+        this.NumberPlays = numberPlays;
+    }
+
+    /// <summary>
+    /// Gets the number of frames
+    /// </summary>
+    public int NumberFrames { get; }
+
+    /// <summary>
+    /// Gets the number of times to loop this APNG.  0 indicates infinite looping.
+    /// </summary>
+    public int NumberPlays { get; }
+
+    /// <summary>
+    /// Writes the acTL to the given buffer.
+    /// </summary>
+    /// <param name="buffer">The buffer to write to.</param>
+    public void WriteTo(Span<byte> buffer)
+    {
+        BinaryPrimitives.WriteInt32BigEndian(buffer[..4], this.NumberFrames);
+        BinaryPrimitives.WriteInt32BigEndian(buffer[4..8], this.NumberPlays);
+    }
+
+    /// <summary>
+    /// Parses the APngAnimationControl from the given data buffer.
+    /// </summary>
+    /// <param name="data">The data to parse.</param>
+    /// <returns>The parsed acTL.</returns>
+    public static AnimationControl Parse(ReadOnlySpan<byte> data)
+        => new(
+            numberFrames: BinaryPrimitives.ReadInt32BigEndian(data[..4]),
+            numberPlays: BinaryPrimitives.ReadInt32BigEndian(data[4..8]));
+}

src/ImageSharp/Formats/Png/Chunks/FrameControl.cs

@@ -0,0 +1,160 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using System.Buffers.Binary;
+
+namespace SixLabors.ImageSharp.Formats.Png.Chunks;
+
+internal readonly struct FrameControl
+{
+    public const int Size = 26;
+
+    public FrameControl(uint width, uint height)
+        : this(0, width, height, 0, 0, 0, 0, default, default)
+    {
+    }
+
+    public FrameControl(
+        uint sequenceNumber,
+        uint width,
+        uint height,
+        uint xOffset,
+        uint yOffset,
+        ushort delayNumerator,
+        ushort delayDenominator,
+        PngDisposalMethod disposeOperation,
+        PngBlendMethod blendOperation)
+    {
+        this.SequenceNumber = sequenceNumber;
+        this.Width = width;
+        this.Height = height;
+        this.XOffset = xOffset;
+        this.YOffset = yOffset;
+        this.DelayNumerator = delayNumerator;
+        this.DelayDenominator = delayDenominator;
+        this.DisposeOperation = disposeOperation;
+        this.BlendOperation = blendOperation;
+    }
+
+    /// <summary>
+    /// Gets the sequence number of the animation chunk, starting from 0
+    /// </summary>
+    public uint SequenceNumber { get; }
+
+    /// <summary>
+    /// Gets the width of the following frame
+    /// </summary>
+    public uint Width { get; }
+
+    /// <summary>
+    /// Gets the height of the following frame
+    /// </summary>
+    public uint Height { get; }
+
+    /// <summary>
+    /// Gets the X position at which to render the following frame
+    /// </summary>
+    public uint XOffset { get; }
+
+    /// <summary>
+    /// Gets the Y position at which to render the following frame
+    /// </summary>
+    public uint YOffset { get; }
+
+    /// <summary>
+    /// Gets the X limit at which to render the following frame
+    /// </summary>
+    public uint XMax => this.XOffset + this.Width;
+
+    /// <summary>
+    /// Gets the Y limit at which to render the following frame
+    /// </summary>
+    public uint YMax => this.YOffset + this.Height;
+
+    /// <summary>
+    /// Gets the frame delay fraction numerator
+    /// </summary>
+    public ushort DelayNumerator { get; }
+
+    /// <summary>
+    /// Gets the frame delay fraction denominator
+    /// </summary>
+    public ushort DelayDenominator { get; }
+
+    /// <summary>
+    /// Gets the type of frame area disposal to be done after rendering this frame
+    /// </summary>
+    public PngDisposalMethod DisposeOperation { get; }
+
+    /// <summary>
+    /// Gets the type of frame area rendering for this frame
+    /// </summary>
+    public PngBlendMethod BlendOperation { get; }
+
+    public Rectangle Bounds => new((int)this.XOffset, (int)this.YOffset, (int)this.Width, (int)this.Height);
+
+    /// <summary>
+    /// Validates the APng fcTL.
+    /// </summary>
+    /// <param name="header">The header.</param>
+    /// <exception cref="NotSupportedException">
+    /// Thrown if the image does pass validation.
+    /// </exception>
+    public void Validate(PngHeader header)
+    {
+        if (this.Width == 0)
+        {
+            PngThrowHelper.ThrowInvalidParameter(this.Width, "Expected > 0");
+        }
+
+        if (this.Height == 0)
+        {
+            PngThrowHelper.ThrowInvalidParameter(this.Height, "Expected > 0");
+        }
+
+        if (this.XMax > header.Width)
+        {
+            PngThrowHelper.ThrowInvalidParameter(this.XOffset, this.Width, $"The x-offset plus width > {nameof(PngHeader)}.{nameof(PngHeader.Width)}");
+        }
+
+        if (this.YMax > header.Height)
+        {
+            PngThrowHelper.ThrowInvalidParameter(this.YOffset, this.Height, $"The y-offset plus height > {nameof(PngHeader)}.{nameof(PngHeader.Height)}");
+        }
+    }
+
+    /// <summary>
+    /// Writes the fcTL to the given buffer.
+    /// </summary>
+    /// <param name="buffer">The buffer to write to.</param>
+    public void WriteTo(Span<byte> buffer)
+    {
+        BinaryPrimitives.WriteUInt32BigEndian(buffer[..4], this.SequenceNumber);
+        BinaryPrimitives.WriteUInt32BigEndian(buffer[4..8], this.Width);
+        BinaryPrimitives.WriteUInt32BigEndian(buffer[8..12], this.Height);
+        BinaryPrimitives.WriteUInt32BigEndian(buffer[12..16], this.XOffset);
+        BinaryPrimitives.WriteUInt32BigEndian(buffer[16..20], this.YOffset);
+        BinaryPrimitives.WriteUInt16BigEndian(buffer[20..22], this.DelayNumerator);
+        BinaryPrimitives.WriteUInt16BigEndian(buffer[22..24], this.DelayDenominator);
+
+        buffer[24] = (byte)this.DisposeOperation;
+        buffer[25] = (byte)this.BlendOperation;
+    }
+
+    /// <summary>
+    /// Parses the APngFrameControl from the given data buffer.
+    /// </summary>
+    /// <param name="data">The data to parse.</param>
+    /// <returns>The parsed fcTL.</returns>
+    public static FrameControl Parse(ReadOnlySpan<byte> data)
+        => new(
+            sequenceNumber: BinaryPrimitives.ReadUInt32BigEndian(data[..4]),
+            width: BinaryPrimitives.ReadUInt32BigEndian(data[4..8]),
+            height: BinaryPrimitives.ReadUInt32BigEndian(data[8..12]),
+            xOffset: BinaryPrimitives.ReadUInt32BigEndian(data[12..16]),
+            yOffset: BinaryPrimitives.ReadUInt32BigEndian(data[16..20]),
+            delayNumerator: BinaryPrimitives.ReadUInt16BigEndian(data[20..22]),
+            delayDenominator: BinaryPrimitives.ReadUInt16BigEndian(data[22..24]),
+            disposeOperation: (PngDisposalMethod)data[24],
+            blendOperation: (PngBlendMethod)data[25]);
+}

src/ImageSharp/Formats/Png/PngHeader.cs → src/ImageSharp/Formats/Png/Chunks/PngHeader.cs

@@ -4,7 +4,7 @@
 
 using System.Buffers.Binary;
 
-namespace SixLabors.ImageSharp.Formats.Png;
+namespace SixLabors.ImageSharp.Formats.Png.Chunks;
 
 /// <summary>
 /// Represents the png header chunk.

src/ImageSharp/Formats/Png/Chunks/PhysicalChunkData.cs → src/ImageSharp/Formats/Png/Chunks/PngPhysical.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
 using System.Buffers.Binary;
@@ -10,11 +10,11 @@ namespace SixLabors.ImageSharp.Formats.Png.Chunks;
 /// <summary>
 /// The pHYs chunk specifies the intended pixel size or aspect ratio for display of the image.
 /// </summary>
-internal readonly struct PhysicalChunkData
+internal readonly struct PngPhysical
 {
     public const int Size = 9;
 
-    public PhysicalChunkData(uint x, uint y, byte unitSpecifier)
+    public PngPhysical(uint x, uint y, byte unitSpecifier)
     {
         this.XAxisPixelsPerUnit = x;
         this.YAxisPixelsPerUnit = y;
@@ -44,13 +44,13 @@ internal readonly struct PhysicalChunkData
     /// </summary>
     /// <param name="data">The data buffer.</param>
     /// <returns>The parsed PhysicalChunkData.</returns>
-    public static PhysicalChunkData Parse(ReadOnlySpan<byte> data)
+    public static PngPhysical Parse(ReadOnlySpan<byte> data)
     {
         uint hResolution = BinaryPrimitives.ReadUInt32BigEndian(data[..4]);
         uint vResolution = BinaryPrimitives.ReadUInt32BigEndian(data.Slice(4, 4));
         byte unit = data[8];
 
-        return new PhysicalChunkData(hResolution, vResolution, unit);
+        return new PngPhysical(hResolution, vResolution, unit);
     }
 
     /// <summary>
@@ -59,7 +59,7 @@ internal readonly struct PhysicalChunkData
     /// </summary>
     /// <param name="meta">The metadata.</param>
     /// <returns>The constructed PngPhysicalChunkData instance.</returns>
-    public static PhysicalChunkData FromMetadata(ImageMetadata meta)
+    public static PngPhysical FromMetadata(ImageMetadata meta)
     {
         byte unitSpecifier = 0;
         uint x;
@@ -92,7 +92,7 @@ internal readonly struct PhysicalChunkData
                 break;
         }
 
-        return new PhysicalChunkData(x, y, unitSpecifier);
+        return new PngPhysical(x, y, unitSpecifier);
     }
 
     /// <summary>

src/ImageSharp/Formats/Png/PngTextData.cs → src/ImageSharp/Formats/Png/Chunks/PngTextData.cs

@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
-namespace SixLabors.ImageSharp.Formats.Png;
+namespace SixLabors.ImageSharp.Formats.Png.Chunks;
 
 /// <summary>
 /// Stores text data contained in the iTXt, tEXt, and zTXt chunks.

src/ImageSharp/Formats/Png/MetadataExtensions.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
 using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Metadata;
 
@@ -14,7 +15,22 @@ public static partial class MetadataExtensions
     /// <summary>
     /// Gets the png format specific metadata for the image.
     /// </summary>
-    /// <param name="metadata">The metadata this method extends.</param>
+    /// <param name="source">The metadata this method extends.</param>
     /// <returns>The <see cref="PngMetadata"/>.</returns>
-    public static PngMetadata GetPngMetadata(this ImageMetadata metadata) => metadata.GetFormatMetadata(PngFormat.Instance);
+    public static PngMetadata GetPngMetadata(this ImageMetadata source) => source.GetFormatMetadata(PngFormat.Instance);
+
+    /// <summary>
+    /// Gets the aPng format specific metadata for the image frame.
+    /// </summary>
+    /// <param name="source">The metadata this method extends.</param>
+    /// <returns>The <see cref="PngFrameMetadata"/>.</returns>
+    public static PngFrameMetadata GetPngFrameMetadata(this ImageFrameMetadata source) => source.GetFormatMetadata(PngFormat.Instance);
+
+    /// <summary>
+    /// Gets the aPng format specific metadata for the image frame.
+    /// </summary>
+    /// <param name="source">The metadata this method extends.</param>
+    /// <param name="metadata">The metadata.</param>
+    /// <returns>The <see cref="PngFrameMetadata"/>.</returns>
+    public static bool TryGetPngFrameMetadata(this ImageFrameMetadata source, [NotNullWhen(true)] out PngFrameMetadata? metadata) => source.TryGetFormatMetadata(PngFormat.Instance, out metadata);
 }

src/ImageSharp/Formats/Png/PngBlendMethod.cs

@@ -0,0 +1,22 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Formats.Png;
+
+/// <summary>
+/// Specifies whether the frame is to be alpha blended into the current output buffer content,
+/// or whether it should completely replace its region in the output buffer.
+/// </summary>
+public enum PngBlendMethod
+{
+    /// <summary>
+    /// All color components of the frame, including alpha, overwrite the current contents of the frame's output buffer region.
+    /// </summary>
+    Source,
+
+    /// <summary>
+    /// The frame should be composited onto the output buffer based on its alpha, using a simple OVER operation as
+    /// described in the "Alpha Channel Processing" section of the PNG specification [PNG-1.2].
+    /// </summary>
+    Over
+}

src/ImageSharp/Formats/Png/PngChunk.cs

@@ -42,7 +42,8 @@ internal readonly struct PngChunk
     /// Gets a value indicating whether the given chunk is critical to decoding
     /// </summary>
     public bool IsCritical =>
-        this.Type == PngChunkType.Header ||
+        this.Type is PngChunkType.Header or
-        this.Type == PngChunkType.Palette ||
+        PngChunkType.Palette or
-        this.Type == PngChunkType.Data;
+        PngChunkType.Data or
+        PngChunkType.FrameData;
 }

src/ImageSharp/Formats/Png/PngChunkType.cs

@@ -9,15 +9,17 @@ namespace SixLabors.ImageSharp.Formats.Png;
 internal enum PngChunkType : uint
 {
     /// <summary>
-    /// The IDAT chunk contains the actual image data. The image can contains more
+    /// This chunk contains the actual image data. The image can contains more
     /// than one chunk of this type. All chunks together are the whole image.
     /// </summary>
+    /// <remarks>IDAT (Multiple)</remarks>
     Data = 0x49444154U,
 
     /// <summary>
     /// This chunk must appear last. It marks the end of the PNG data stream.
     /// The chunk's data field is empty.
     /// </summary>
+    /// <remarks>IEND (Single)</remarks>
     End = 0x49454E44U,
 
     /// <summary>
@@ -25,34 +27,40 @@ internal enum PngChunkType : uint
     /// common information like the width and the height of the image or
     /// the used compression method.
     /// </summary>
+    /// <remarks>IHDR (Single)</remarks>
     Header = 0x49484452U,
 
     /// <summary>
     /// The PLTE chunk contains from 1 to 256 palette entries, each a three byte
     /// series in the RGB format.
     /// </summary>
+    /// <remarks>PLTE (Single)</remarks>
     Palette = 0x504C5445U,
 
     /// <summary>
     /// The eXIf data chunk which contains the Exif profile.
     /// </summary>
+    /// <remarks>eXIF (Single)</remarks>
     Exif = 0x65584966U,
 
     /// <summary>
     /// This chunk specifies the relationship between the image samples and the desired
     /// display output intensity.
     /// </summary>
+    /// <remarks>gAMA (Single)</remarks>
     Gamma = 0x67414D41U,
 
     /// <summary>
-    /// The pHYs chunk specifies the intended pixel size or aspect ratio for display of the image.
+    /// This chunk specifies the intended pixel size or aspect ratio for display of the image.
     /// </summary>
+    /// <remarks>pHYs (Single)</remarks>
     Physical = 0x70485973U,
 
     /// <summary>
     /// Textual information that the encoder wishes to record with the image can be stored in
     /// tEXt chunks. Each tEXt chunk contains a keyword and a text string.
     /// </summary>
+    /// <remarks>tEXT (Multiple)</remarks>
     Text = 0x74455874U,
 
     /// <summary>
@@ -60,70 +68,103 @@ internal enum PngChunkType : uint
     /// but the zTXt chunk is recommended for storing large blocks of text. Each zTXt chunk contains a (uncompressed) keyword and
     /// a compressed text string.
     /// </summary>
+    /// <remarks>zTXt (Multiple)</remarks>
     CompressedText = 0x7A545874U,
 
     /// <summary>
-    /// The iTXt chunk contains International textual data. It contains a keyword, an optional language tag, an optional translated keyword
+    /// This chunk contains International textual data. It contains a keyword, an optional language tag, an optional translated keyword
     /// and the actual text string, which can be compressed or uncompressed.
     /// </summary>
+    /// <remarks>iTXt (Multiple)</remarks>
     InternationalText = 0x69545874U,
 
     /// <summary>
-    /// The tRNS chunk specifies that the image uses simple transparency:
+    /// This chunk specifies that the image uses simple transparency:
     /// either alpha values associated with palette entries (for indexed-color images)
     /// or a single transparent color (for grayscale and true color images).
     /// </summary>
+    /// <remarks>tRNS (Single)</remarks>
     Transparency = 0x74524E53U,
 
     /// <summary>
-    /// The tIME chunk gives the time of the last image modification (not the time of initial image creation).
+    /// This chunk gives the time of the last image modification (not the time of initial image creation).
     /// </summary>
+    /// <remarks>tIME (Single)</remarks>
     Time = 0x74494d45,
 
     /// <summary>
-    /// The bKGD chunk specifies a default background colour to present the image against.
+    /// This chunk specifies a default background colour to present the image against.
     /// If there is any other preferred background, either user-specified or part of a larger page (as in a browser),
     /// the bKGD chunk should be ignored.
     /// </summary>
+    /// <remarks>bKGD (Single)</remarks>
     Background = 0x624b4744,
 
     /// <summary>
-    /// The iCCP chunk contains a embedded color profile. If the iCCP chunk is present,
+    /// This chunk contains a embedded color profile. If the iCCP chunk is present,
     /// the image samples conform to the colour space represented by the embedded ICC profile as defined by the International Color Consortium.
     /// </summary>
+    /// <remarks>iCCP (Single)</remarks>
     EmbeddedColorProfile = 0x69434350,
 
     /// <summary>
-    /// The sBIT chunk defines the original number of significant bits (which can be less than or equal to the sample depth).
+    /// This chunk defines the original number of significant bits (which can be less than or equal to the sample depth).
     /// This allows PNG decoders to recover the original data losslessly even if the data had a sample depth not directly supported by PNG.
     /// </summary>
+    /// <remarks>sBIT (Single)</remarks>
     SignificantBits = 0x73424954,
 
     /// <summary>
-    /// If the sRGB chunk is present, the image samples conform to the sRGB colour space [IEC 61966-2-1] and should be displayed
+    /// If the this chunk is present, the image samples conform to the sRGB colour space [IEC 61966-2-1] and should be displayed
     /// using the specified rendering intent defined by the International Color Consortium.
     /// </summary>
+    /// <remarks>sRGB (Single)</remarks>
     StandardRgbColourSpace = 0x73524742,
 
     /// <summary>
-    /// The hIST chunk gives the approximate usage frequency of each colour in the palette.
+    /// This chunk gives the approximate usage frequency of each colour in the palette.
     /// </summary>
+    /// <remarks>hIST (Single)</remarks>
     Histogram = 0x68495354,
 
     /// <summary>
-    /// The sPLT chunk contains the suggested palette.
+    /// This chunk contains the suggested palette.
     /// </summary>
+    /// <remarks>sPLT (Single)</remarks>
     SuggestedPalette = 0x73504c54,
 
     /// <summary>
-    /// The cHRM chunk may be used to specify the 1931 CIE x,y chromaticities of the red,
+    /// This chunk may be used to specify the 1931 CIE x,y chromaticities of the red,
     /// green, and blue display primaries used in the image, and the referenced white point.
     /// </summary>
+    /// <remarks>cHRM (Single)</remarks>
     Chroma = 0x6348524d,
 
+    /// <summary>
+    /// This chunk is an ancillary chunk as defined in the PNG Specification.
+    /// It must appear before the first IDAT chunk within a valid PNG stream.
+    /// </summary>
+    /// <remarks>acTL (Single, APNG)</remarks>
+    AnimationControl = 0x6163544cU,
+
+    /// <summary>
+    /// This chunk is an ancillary chunk as defined in the PNG Specification.
+    /// It must appear before the IDAT or fdAT chunks of the frame to which it applies.
+    /// </summary>
+    /// <remarks>fcTL (Multiple, APNG)</remarks>
+    FrameControl = 0x6663544cU,
+
+    /// <summary>
+    /// This chunk has the same purpose as an IDAT chunk.
+    /// It has the same structure as an IDAT chunk, except preceded by a sequence number.
+    /// </summary>
+    /// <remarks>fdAT (Multiple, APNG)</remarks>
+    FrameData = 0x66644154U,
+
     /// <summary>
     /// Malformed chunk named CgBI produced by apple, which is not conform to the specification.
     /// Related issue is here https://github.com/SixLabors/ImageSharp/issues/410
     /// </summary>
+    /// <remarks>CgBI</remarks>
     ProprietaryApple = 0x43674249
 }

src/ImageSharp/Formats/Png/PngConstants.cs

@@ -28,12 +28,12 @@ internal static class PngConstants
     /// <summary>
     /// The list of mimetypes that equate to a Png.
     /// </summary>
-    public static readonly IEnumerable<string> MimeTypes = new[] { "image/png" };
+    public static readonly IEnumerable<string> MimeTypes = new[] { "image/png", "image/apng" };
 
     /// <summary>
     /// The list of file extensions that equate to a Png.
     /// </summary>
-    public static readonly IEnumerable<string> FileExtensions = new[] { "png" };
+    public static readonly IEnumerable<string> FileExtensions = new[] { "png", "apng" };
 
     /// <summary>
     /// The header bytes as a big-endian coded ulong.
@@ -43,7 +43,7 @@ internal static class PngConstants
     /// <summary>
     /// The dictionary of available color types.
     /// </summary>
-    public static readonly Dictionary<PngColorType, byte[]> ColorTypes = new Dictionary<PngColorType, byte[]>
+    public static readonly Dictionary<PngColorType, byte[]> ColorTypes = new()
     {
         [PngColorType.Grayscale] = new byte[] { 1, 2, 4, 8, 16 },
         [PngColorType.Rgb] = new byte[] { 8, 16 },
@@ -80,7 +80,7 @@ internal static class PngConstants
     /// <summary>
     /// Gets the keyword of the XMP metadata, encoded in an iTXT chunk.
     /// </summary>
-    public static ReadOnlySpan<byte> XmpKeyword => new byte[]
+    public static ReadOnlySpan<byte> XmpKeyword => new[]
     {
         (byte)'X',
         (byte)'M',

src/ImageSharp/Formats/Png/PngDecoder.cs

@@ -61,24 +61,24 @@ public sealed class PngDecoder : ImageDecoder
             case PngColorType.Grayscale:
                 if (bits == PngBitDepth.Bit16)
                 {
-                    return !meta.HasTransparency
+                    return !meta.TransparentColor.HasValue
                         ? this.Decode<L16>(options, stream, cancellationToken)
                         : this.Decode<La32>(options, stream, cancellationToken);
                 }
 
-                return !meta.HasTransparency
+                return !meta.TransparentColor.HasValue
                     ? this.Decode<L8>(options, stream, cancellationToken)
                     : this.Decode<La16>(options, stream, cancellationToken);
 
             case PngColorType.Rgb:
                 if (bits == PngBitDepth.Bit16)
                 {
-                    return !meta.HasTransparency
+                    return !meta.TransparentColor.HasValue
                         ? this.Decode<Rgb48>(options, stream, cancellationToken)
                         : this.Decode<Rgba64>(options, stream, cancellationToken);
                 }
 
-                return !meta.HasTransparency
+                return !meta.TransparentColor.HasValue
                     ? this.Decode<Rgb24>(options, stream, cancellationToken)
                     : this.Decode<Rgba32>(options, stream, cancellationToken);
 

src/ImageSharp/Formats/Png/PngDisposalMethod.cs

@@ -0,0 +1,25 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Formats.Png;
+
+/// <summary>
+/// Specifies how the output buffer should be changed at the end of the delay (before rendering the next frame).
+/// </summary>
+public enum PngDisposalMethod
+{
+    /// <summary>
+    /// No disposal is done on this frame before rendering the next; the contents of the output buffer are left as is.
+    /// </summary>
+    None,
+
+    /// <summary>
+    /// The frame's region of the output buffer is to be cleared to fully transparent black before rendering the next frame.
+    /// </summary>
+    Background,
+
+    /// <summary>
+    /// The frame's region of the output buffer is to be reverted to the previous contents before rendering the next frame.
+    /// </summary>
+    Previous
+}

src/ImageSharp/Formats/Png/PngEncoder.cs

@@ -2,7 +2,7 @@
 // Licensed under the Six Labors Split License.
 #nullable disable
 
-using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.Processing.Processors.Quantization;
 
 namespace SixLabors.ImageSharp.Formats.Png;
 
@@ -11,6 +11,16 @@ namespace SixLabors.ImageSharp.Formats.Png;
 /// </summary>
 public class PngEncoder : QuantizingImageEncoder
 {
+    /// <summary>
+    /// Initializes a new instance of the <see cref="PngEncoder"/> class.
+    /// </summary>
+    public PngEncoder()
+
+        // Hack. TODO: Investigate means to fix/optimize the Wu quantizer.
+        // The Wu quantizer does not handle the default sampling strategy well for some larger images.
+        // It's expensive and the results are not better than the extensive strategy.
+        => this.PixelSamplingStrategy = new ExtensivePixelSamplingStrategy();
+
     /// <summary>
     /// Gets the number of bits per sample or per palette index (not per pixel).
     /// Not all values are allowed for all <see cref="ColorType" /> values.
@@ -68,7 +78,7 @@ public class PngEncoder : QuantizingImageEncoder
     /// <inheritdoc/>
     protected override void Encode<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
     {
-        using PngEncoderCore encoder = new(image.GetMemoryAllocator(), image.GetConfiguration(), this);
+        using PngEncoderCore encoder = new(image.Configuration, this);
         encoder.Encode(image, stream, cancellationToken);
     }
 }

src/ImageSharp/Formats/Png/PngEncoderCore.cs

@@ -1,12 +1,10 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
 using System.Buffers.Binary;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
-using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Common.Helpers;
 using SixLabors.ImageSharp.Compression.Zlib;
 using SixLabors.ImageSharp.Formats.Png.Chunks;
@@ -101,29 +99,34 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// <summary>
     /// The raw data of previous scanline.
     /// </summary>
-    private IMemoryOwner<byte> previousScanline;
+    private IMemoryOwner<byte> previousScanline = null!;
 
     /// <summary>
     /// The raw data of current scanline.
     /// </summary>
-    private IMemoryOwner<byte> currentScanline;
+    private IMemoryOwner<byte> currentScanline = null!;
 
     /// <summary>
     /// The color profile name.
     /// </summary>
     private const string ColorProfileName = "ICC Profile";
 
+    /// <summary>
+    /// The encoder quantizer, if present.
+    /// </summary>
+    private IQuantizer? quantizer;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="PngEncoderCore" /> class.
     /// </summary>
-    /// <param name="memoryAllocator">The <see cref="MemoryAllocator" /> to use for buffer allocations.</param>
     /// <param name="configuration">The configuration.</param>
     /// <param name="encoder">The encoder with options.</param>
-    public PngEncoderCore(MemoryAllocator memoryAllocator, Configuration configuration, PngEncoder encoder)
+    public PngEncoderCore(Configuration configuration, PngEncoder encoder)
     {
-        this.memoryAllocator = memoryAllocator;
         this.configuration = configuration;
+        this.memoryAllocator = configuration.MemoryAllocator;
         this.encoder = encoder;
+        this.quantizer = encoder.Quantizer;
     }
 
     /// <summary>
@@ -143,20 +146,23 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         this.height = image.Height;
 
         ImageMetadata metadata = image.Metadata;
-
         PngMetadata pngMetadata = metadata.GetFormatMetadata(PngFormat.Instance);
         this.SanitizeAndSetEncoderOptions<TPixel>(this.encoder, pngMetadata, out this.use16Bit, out this.bytesPerPixel);
-        Image<TPixel> clonedImage = null;
+
-        bool clearTransparency = this.encoder.TransparentColorMode == PngTransparentColorMode.Clear;
+        stream.Write(PngConstants.HeaderBytes);
+
+        ImageFrame<TPixel>? clonedFrame = null;
+        ImageFrame<TPixel> currentFrame = image.Frames.RootFrame;
+
+        bool clearTransparency = this.encoder.TransparentColorMode is PngTransparentColorMode.Clear;
         if (clearTransparency)
         {
-            clonedImage = image.Clone();
+            currentFrame = clonedFrame = currentFrame.Clone();
-            ClearTransparentPixels(clonedImage);
+            ClearTransparentPixels(currentFrame);
         }
 
-        IndexedImageFrame<TPixel> quantized = this.CreateQuantizedImageAndUpdateBitDepth(image, clonedImage);
+        // Do not move this. We require an accurate bit depth for the header chunk.
-
+        IndexedImageFrame<TPixel>? quantized = this.CreateQuantizedImageAndUpdateBitDepth(pngMetadata, currentFrame, null);
-        stream.Write(PngConstants.HeaderBytes);
 
         this.WriteHeaderChunk(stream);
         this.WriteGammaChunk(stream);
@@ -167,13 +173,58 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         this.WriteExifChunk(stream, metadata);
         this.WriteXmpChunk(stream, metadata);
         this.WriteTextChunks(stream, pngMetadata);
-        this.WriteDataChunks(clearTransparency ? clonedImage : image, quantized, stream);
+
+        if (image.Frames.Count > 1)
+        {
+            this.WriteAnimationControlChunk(stream, image.Frames.Count, pngMetadata.RepeatCount);
+
+            // TODO: We should attempt to optimize the output by clipping the indexed result to
+            // non-transparent bounds. That way we can assign frame control bounds and encode
+            // less data. See GifEncoder for the implementation there.
+
+            // Write the first frame.
+            FrameControl frameControl = this.WriteFrameControlChunk(stream, currentFrame, 0);
+            this.WriteDataChunks(frameControl, currentFrame, quantized, stream, false);
+
+            // Capture the global palette for reuse on subsequent frames.
+            ReadOnlyMemory<TPixel>? previousPalette = quantized?.Palette.ToArray();
+
+            // Write following frames.
+            uint increment = 0;
+            for (int i = 1; i < image.Frames.Count; i++)
+            {
+                currentFrame = image.Frames[i];
+                if (clearTransparency)
+                {
+                    // Dispose of previous clone and reassign.
+                    clonedFrame?.Dispose();
+                    currentFrame = clonedFrame = currentFrame.Clone();
+                    ClearTransparentPixels(currentFrame);
+                }
+
+                // Each frame control sequence number must be incremented by the
+                // number of frame data chunks that follow.
+                frameControl = this.WriteFrameControlChunk(stream, currentFrame, (uint)i + increment);
+
+                // Dispose of previous quantized frame and reassign.
+                quantized?.Dispose();
+                quantized = this.CreateQuantizedImageAndUpdateBitDepth(pngMetadata, currentFrame, previousPalette);
+                increment += this.WriteDataChunks(frameControl, currentFrame, quantized, stream, true);
+            }
+        }
+        else
+        {
+            FrameControl frameControl = new((uint)this.width, (uint)this.height);
+            this.WriteDataChunks(frameControl, currentFrame, quantized, stream, false);
+        }
+
         this.WriteEndChunk(stream);
 
         stream.Flush();
 
+        // Dispose of allocations from final frame.
+        clonedFrame?.Dispose();
         quantized?.Dispose();
-        clonedImage?.Dispose();
     }
 
     /// <inheritdoc />
@@ -181,18 +232,16 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     {
         this.previousScanline?.Dispose();
         this.currentScanline?.Dispose();
-        this.previousScanline = null;
-        this.currentScanline = null;
     }
 
     /// <summary>
     /// Convert transparent pixels, to transparent black pixels, which can yield to better compression in some cases.
     /// </summary>
     /// <typeparam name="TPixel">The type of the pixel.</typeparam>
-    /// <param name="image">The cloned image where the transparent pixels will be changed.</param>
+    /// <param name="clone">The cloned image frame where the transparent pixels will be changed.</param>
-    private static void ClearTransparentPixels<TPixel>(Image<TPixel> image)
+    private static void ClearTransparentPixels<TPixel>(ImageFrame<TPixel> clone)
-        where TPixel : unmanaged, IPixel<TPixel> =>
+        where TPixel : unmanaged, IPixel<TPixel>
-        image.ProcessPixelRows(accessor =>
+        => clone.ProcessPixelRows(accessor =>
         {
             // TODO: We should be able to speed this up with SIMD and masking.
             Rgba32 rgba32 = default;
@@ -204,7 +253,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
                 {
                     span[x].ToRgba32(ref rgba32);
 
-                    if (rgba32.A == 0)
+                    if (rgba32.A is 0)
                     {
                         span[x].FromRgba32(transparent);
                     }
@@ -216,24 +265,17 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// Creates the quantized image and calculates and sets the bit depth.
     /// </summary>
     /// <typeparam name="TPixel">The type of the pixel.</typeparam>
-    /// <param name="image">The image to quantize.</param>
+    /// <param name="metadata">The image metadata.</param>
-    /// <param name="clonedImage">Cloned image with transparent pixels are changed to black.</param>
+    /// <param name="frame">The frame to quantize.</param>
+    /// <param name="previousPalette">Any previously derived palette.</param>
     /// <returns>The quantized image.</returns>
-    private IndexedImageFrame<TPixel> CreateQuantizedImageAndUpdateBitDepth<TPixel>(
+    private IndexedImageFrame<TPixel>? CreateQuantizedImageAndUpdateBitDepth<TPixel>(
-        Image<TPixel> image,
+        PngMetadata metadata,
-        Image<TPixel> clonedImage)
+        ImageFrame<TPixel> frame,
+        ReadOnlyMemory<TPixel>? previousPalette)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        IndexedImageFrame<TPixel> quantized;
+        IndexedImageFrame<TPixel>? quantized = this.CreateQuantizedFrame(this.encoder, this.colorType, this.bitDepth, metadata, frame, previousPalette);
-        if (this.encoder.TransparentColorMode == PngTransparentColorMode.Clear)
-        {
-            quantized = CreateQuantizedFrame(this.encoder, this.colorType, this.bitDepth, clonedImage);
-        }
-        else
-        {
-            quantized = CreateQuantizedFrame(this.encoder, this.colorType, this.bitDepth, image);
-        }
-
         this.bitDepth = CalculateBitDepth(this.colorType, this.bitDepth, quantized);
         return quantized;
     }
@@ -244,9 +286,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     private void CollectGrayscaleBytes<TPixel>(ReadOnlySpan<TPixel> rowSpan)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
         Span<byte> rawScanlineSpan = this.currentScanline.GetSpan();
-        ref byte rawScanlineSpanRef = ref MemoryMarshal.GetReference(rawScanlineSpan);
 
         if (this.colorType == PngColorType.Grayscale)
         {
@@ -402,20 +442,19 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// <param name="rowSpan">The row span.</param>
     /// <param name="quantized">The quantized pixels. Can be null.</param>
     /// <param name="row">The row.</param>
-    private void CollectPixelBytes<TPixel>(ReadOnlySpan<TPixel> rowSpan, IndexedImageFrame<TPixel> quantized, int row)
+    private void CollectPixelBytes<TPixel>(ReadOnlySpan<TPixel> rowSpan, IndexedImageFrame<TPixel>? quantized, int row)
         where TPixel : unmanaged, IPixel<TPixel>
     {
         switch (this.colorType)
         {
             case PngColorType.Palette:
-
                 if (this.bitDepth < 8)
                 {
-                    PngEncoderHelpers.ScaleDownFrom8BitArray(quantized.DangerousGetRowSpan(row), this.currentScanline.GetSpan(), this.bitDepth);
+                    PngEncoderHelpers.ScaleDownFrom8BitArray(quantized!.DangerousGetRowSpan(row), this.currentScanline.GetSpan(), this.bitDepth);
                 }
                 else
                 {
-                    quantized.DangerousGetRowSpan(row).CopyTo(this.currentScanline.GetSpan());
+                    quantized?.DangerousGetRowSpan(row).CopyTo(this.currentScanline.GetSpan());
                 }
 
                 break;
@@ -476,7 +515,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         ReadOnlySpan<TPixel> rowSpan,
         ref Span<byte> filter,
         ref Span<byte> attempt,
-        IndexedImageFrame<TPixel> quantized,
+        IndexedImageFrame<TPixel>? quantized,
         int row)
         where TPixel : unmanaged, IPixel<TPixel>
     {
@@ -576,6 +615,21 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         this.WriteChunk(stream, PngChunkType.Header, this.chunkDataBuffer.Span, 0, PngHeader.Size);
     }
 
+    /// <summary>
+    /// Writes the animation control chunk to the stream.
+    /// </summary>
+    /// <param name="stream">The <see cref="Stream"/> containing image data.</param>
+    /// <param name="framesCount">The number of frames.</param>
+    /// <param name="playsCount">The number of times to loop this APNG.</param>
+    private void WriteAnimationControlChunk(Stream stream, int framesCount, int playsCount)
+    {
+        AnimationControl acTL = new(framesCount, playsCount);
+
+        acTL.WriteTo(this.chunkDataBuffer.Span);
+
+        this.WriteChunk(stream, PngChunkType.AnimationControl, this.chunkDataBuffer.Span, 0, AnimationControl.Size);
+    }
+
     /// <summary>
     /// Writes the palette chunk to the stream.
     /// Should be written before the first IDAT chunk.
@@ -583,7 +637,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// <typeparam name="TPixel">The pixel format.</typeparam>
     /// <param name="stream">The <see cref="Stream"/> containing image data.</param>
     /// <param name="quantized">The quantized frame.</param>
-    private void WritePaletteChunk<TPixel>(Stream stream, IndexedImageFrame<TPixel> quantized)
+    private void WritePaletteChunk<TPixel>(Stream stream, IndexedImageFrame<TPixel>? quantized)
         where TPixel : unmanaged, IPixel<TPixel>
     {
         if (quantized is null)
@@ -642,14 +696,14 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// <param name="meta">The image metadata.</param>
     private void WritePhysicalChunk(Stream stream, ImageMetadata meta)
     {
-        if ((this.chunkFilter & PngChunkFilter.ExcludePhysicalChunk) == PngChunkFilter.ExcludePhysicalChunk)
+        if (this.chunkFilter.HasFlag(PngChunkFilter.ExcludePhysicalChunk))
         {
             return;
         }
 
-        PhysicalChunkData.FromMetadata(meta).WriteTo(this.chunkDataBuffer.Span);
+        PngPhysical.FromMetadata(meta).WriteTo(this.chunkDataBuffer.Span);
 
-        this.WriteChunk(stream, PngChunkType.Physical, this.chunkDataBuffer.Span, 0, PhysicalChunkData.Size);
+        this.WriteChunk(stream, PngChunkType.Physical, this.chunkDataBuffer.Span, 0, PngPhysical.Size);
     }
 
     /// <summary>
@@ -691,9 +745,9 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
             return;
         }
 
-        byte[] xmpData = meta.XmpProfile.Data;
+        byte[]? xmpData = meta.XmpProfile.Data;
 
-        if (xmpData.Length == 0)
+        if (xmpData?.Length is 0 or null)
         {
             return;
         }
@@ -760,18 +814,9 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         }
 
         const int maxLatinCode = 255;
-        for (int i = 0; i < meta.TextData.Count; i++)
+        foreach (PngTextData textData in meta.TextData)
         {
-            PngTextData textData = meta.TextData[i];
+            bool hasUnicodeCharacters = textData.Value.Any(c => c > maxLatinCode);
-            bool hasUnicodeCharacters = false;
-            foreach (char c in textData.Value)
-            {
-                if (c > maxLatinCode)
-                {
-                    hasUnicodeCharacters = true;
-                    break;
-                }
-            }
 
             if (hasUnicodeCharacters || !string.IsNullOrWhiteSpace(textData.LanguageTag) || !string.IsNullOrWhiteSpace(textData.TranslatedKeyword))
             {
@@ -875,7 +920,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
             // 4-byte unsigned integer of gamma * 100,000.
             uint gammaValue = (uint)(this.gamma * 100_000F);
 
-            BinaryPrimitives.WriteUInt32BigEndian(this.chunkDataBuffer.Span.Slice(0, 4), gammaValue);
+            BinaryPrimitives.WriteUInt32BigEndian(this.chunkDataBuffer.Span[..4], gammaValue);
 
             this.WriteChunk(stream, PngChunkType.Gamma, this.chunkDataBuffer.Span, 0, 4);
         }
@@ -889,7 +934,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// <param name="pngMetadata">The image metadata.</param>
     private void WriteTransparencyChunk(Stream stream, PngMetadata pngMetadata)
     {
-        if (!pngMetadata.HasTransparency)
+        if (pngMetadata.TransparentColor is null)
         {
             return;
         }
@@ -897,19 +942,19 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         Span<byte> alpha = this.chunkDataBuffer.Span;
         if (pngMetadata.ColorType == PngColorType.Rgb)
         {
-            if (pngMetadata.TransparentRgb48.HasValue && this.use16Bit)
+            if (this.use16Bit)
             {
-                Rgb48 rgb = pngMetadata.TransparentRgb48.Value;
+                Rgb48 rgb = pngMetadata.TransparentColor.Value.ToPixel<Rgb48>();
                 BinaryPrimitives.WriteUInt16LittleEndian(alpha, rgb.R);
                 BinaryPrimitives.WriteUInt16LittleEndian(alpha.Slice(2, 2), rgb.G);
                 BinaryPrimitives.WriteUInt16LittleEndian(alpha.Slice(4, 2), rgb.B);
 
                 this.WriteChunk(stream, PngChunkType.Transparency, this.chunkDataBuffer.Span, 0, 6);
             }
-            else if (pngMetadata.TransparentRgb24.HasValue)
+            else
             {
                 alpha.Clear();
-                Rgb24 rgb = pngMetadata.TransparentRgb24.Value;
+                Rgb24 rgb = pngMetadata.TransparentColor.Value.ToRgb24();
                 alpha[1] = rgb.R;
                 alpha[3] = rgb.G;
                 alpha[5] = rgb.B;
@@ -918,28 +963,61 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         }
         else if (pngMetadata.ColorType == PngColorType.Grayscale)
         {
-            if (pngMetadata.TransparentL16.HasValue && this.use16Bit)
+            if (this.use16Bit)
             {
-                BinaryPrimitives.WriteUInt16LittleEndian(alpha, pngMetadata.TransparentL16.Value.PackedValue);
+                L16 l16 = pngMetadata.TransparentColor.Value.ToPixel<L16>();
+                BinaryPrimitives.WriteUInt16LittleEndian(alpha, l16.PackedValue);
                 this.WriteChunk(stream, PngChunkType.Transparency, this.chunkDataBuffer.Span, 0, 2);
             }
-            else if (pngMetadata.TransparentL8.HasValue)
+            else
             {
+                L8 l8 = pngMetadata.TransparentColor.Value.ToPixel<L8>();
                 alpha.Clear();
-                alpha[1] = pngMetadata.TransparentL8.Value.PackedValue;
+                alpha[1] = l8.PackedValue;
                 this.WriteChunk(stream, PngChunkType.Transparency, this.chunkDataBuffer.Span, 0, 2);
             }
         }
     }
 
+    /// <summary>
+    /// Writes the animation control chunk to the stream.
+    /// </summary>
+    /// <param name="stream">The <see cref="Stream"/> containing image data.</param>
+    /// <param name="imageFrame">The image frame.</param>
+    /// <param name="sequenceNumber">The frame sequence number.</param>
+    private FrameControl WriteFrameControlChunk(Stream stream, ImageFrame imageFrame, uint sequenceNumber)
+    {
+        PngFrameMetadata frameMetadata = imageFrame.Metadata.GetPngFrameMetadata();
+
+        // TODO: If we can clip the indexed frame for transparent bounds we can set properties here.
+        FrameControl fcTL = new(
+            sequenceNumber: sequenceNumber,
+            width: (uint)imageFrame.Width,
+            height: (uint)imageFrame.Height,
+            xOffset: 0,
+            yOffset: 0,
+            delayNumerator: (ushort)frameMetadata.FrameDelay.Numerator,
+            delayDenominator: (ushort)frameMetadata.FrameDelay.Denominator,
+            disposeOperation: frameMetadata.DisposalMethod,
+            blendOperation: frameMetadata.BlendMethod);
+
+        fcTL.WriteTo(this.chunkDataBuffer.Span);
+
+        this.WriteChunk(stream, PngChunkType.FrameControl, this.chunkDataBuffer.Span, 0, FrameControl.Size);
+
+        return fcTL;
+    }
+
     /// <summary>
     /// Writes the pixel information to the stream.
     /// </summary>
     /// <typeparam name="TPixel">The pixel format.</typeparam>
-    /// <param name="pixels">The image.</param>
+    /// <param name="frameControl">The frame control</param>
+    /// <param name="pixels">The frame.</param>
     /// <param name="quantized">The quantized pixel data. Can be null.</param>
     /// <param name="stream">The stream.</param>
-    private void WriteDataChunks<TPixel>(Image<TPixel> pixels, IndexedImageFrame<TPixel> quantized, Stream stream)
+    /// <param name="isFrame">Is writing fdAT or IDAT.</param>
+    private uint WriteDataChunks<TPixel>(FrameControl frameControl, ImageFrame<TPixel> pixels, IndexedImageFrame<TPixel>? quantized, Stream stream, bool isFrame)
         where TPixel : unmanaged, IPixel<TPixel>
     {
         byte[] buffer;
@@ -949,20 +1027,20 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         {
             using (ZlibDeflateStream deflateStream = new(this.memoryAllocator, memoryStream, this.encoder.CompressionLevel))
             {
-                if (this.interlaceMode == PngInterlaceMode.Adam7)
+                if (this.interlaceMode is PngInterlaceMode.Adam7)
                 {
-                    if (quantized != null)
+                    if (quantized is not null)
                     {
-                        this.EncodeAdam7IndexedPixels(quantized, deflateStream);
+                        this.EncodeAdam7IndexedPixels(frameControl, quantized, deflateStream);
                     }
                     else
                     {
-                        this.EncodeAdam7Pixels(pixels, deflateStream);
+                        this.EncodeAdam7Pixels(frameControl, pixels, deflateStream);
                     }
                 }
                 else
                 {
-                    this.EncodePixels(pixels, quantized, deflateStream);
+                    this.EncodePixels(frameControl, pixels, quantized, deflateStream);
                 }
             }
 
@@ -972,24 +1050,42 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
 
         // Store the chunks in repeated 64k blocks.
         // This reduces the memory load for decoding the image for many decoders.
-        int numChunks = bufferLength / MaxBlockSize;
+        int maxBlockSize = MaxBlockSize;
+        if (isFrame)
+        {
+            maxBlockSize -= 4;
+        }
 
-        if (bufferLength % MaxBlockSize != 0)
+        int numChunks = bufferLength / maxBlockSize;
+
+        if (bufferLength % maxBlockSize != 0)
         {
             numChunks++;
         }
 
         for (int i = 0; i < numChunks; i++)
         {
-            int length = bufferLength - (i * MaxBlockSize);
+            int length = bufferLength - (i * maxBlockSize);
 
-            if (length > MaxBlockSize)
+            if (length > maxBlockSize)
             {
-                length = MaxBlockSize;
+                length = maxBlockSize;
             }
 
-            this.WriteChunk(stream, PngChunkType.Data, buffer, i * MaxBlockSize, length);
+            if (isFrame)
+            {
+                // We increment the sequence number for each frame chunk.
+                // '1' is added to the sequence number to account for the preceding frame control chunk.
+                uint sequenceNumber = (uint)(frameControl.SequenceNumber + 1 + i);
+                this.WriteFrameDataChunk(stream, sequenceNumber, buffer, i * maxBlockSize, length);
+            }
+            else
+            {
+                this.WriteChunk(stream, PngChunkType.Data, buffer, i * maxBlockSize, length);
+            }
         }
+
+        return (uint)numChunks;
     }
 
     /// <summary>
@@ -1009,13 +1105,17 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// Encodes the pixels.
     /// </summary>
     /// <typeparam name="TPixel">The type of the pixel.</typeparam>
+    /// <param name="frameControl">The frame control</param>
     /// <param name="pixels">The pixels.</param>
     /// <param name="quantized">The quantized pixels span.</param>
     /// <param name="deflateStream">The deflate stream.</param>
-    private void EncodePixels<TPixel>(Image<TPixel> pixels, IndexedImageFrame<TPixel> quantized, ZlibDeflateStream deflateStream)
+    private void EncodePixels<TPixel>(FrameControl frameControl, ImageFrame<TPixel> pixels, IndexedImageFrame<TPixel>? quantized, ZlibDeflateStream deflateStream)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        int bytesPerScanline = this.CalculateScanlineLength(this.width);
+        int width = (int)frameControl.Width;
+        int height = (int)frameControl.Height;
+
+        int bytesPerScanline = this.CalculateScanlineLength(width);
         int filterLength = bytesPerScanline + 1;
         this.AllocateScanlineBuffers(bytesPerScanline);
 
@@ -1026,7 +1126,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         {
             Span<byte> filter = filterBuffer.GetSpan();
             Span<byte> attempt = attemptBuffer.GetSpan();
-            for (int y = 0; y < this.height; y++)
+            for (int y = (int)frameControl.YOffset; y < frameControl.YMax; y++)
             {
                 this.CollectAndFilterPixelRow(accessor.GetRowSpan(y), ref filter, ref attempt, quantized, y);
                 deflateStream.Write(filter);
@@ -1039,18 +1139,19 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// Interlaced encoding the pixels.
     /// </summary>
     /// <typeparam name="TPixel">The type of the pixel.</typeparam>
-    /// <param name="image">The image.</param>
+    /// <param name="frameControl">The frame control</param>
+    /// <param name="frame">The image frame.</param>
     /// <param name="deflateStream">The deflate stream.</param>
-    private void EncodeAdam7Pixels<TPixel>(Image<TPixel> image, ZlibDeflateStream deflateStream)
+    private void EncodeAdam7Pixels<TPixel>(FrameControl frameControl, ImageFrame<TPixel> frame, ZlibDeflateStream deflateStream)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        int width = image.Width;
+        int width = (int)frameControl.XMax;
-        int height = image.Height;
+        int height = (int)frameControl.YMax;
-        Buffer2D<TPixel> pixelBuffer = image.Frames.RootFrame.PixelBuffer;
+        Buffer2D<TPixel> pixelBuffer = frame.PixelBuffer;
         for (int pass = 0; pass < 7; pass++)
         {
-            int startRow = Adam7.FirstRow[pass];
+            int startRow = Adam7.FirstRow[pass] + (int)frameControl.YOffset;
-            int startCol = Adam7.FirstColumn[pass];
+            int startCol = Adam7.FirstColumn[pass] + (int)frameControl.XOffset;
             int blockWidth = Adam7.ComputeBlockWidth(width, pass);
 
             int bytesPerScanline = this.bytesPerPixel <= 1
@@ -1072,7 +1173,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
             {
                 // Collect pixel data
                 Span<TPixel> srcRow = pixelBuffer.DangerousGetRowSpan(row);
-                for (int col = startCol, i = 0; col < width; col += Adam7.ColumnIncrement[pass])
+                for (int col = startCol, i = 0; col < frameControl.XMax; col += Adam7.ColumnIncrement[pass])
                 {
                     block[i++] = srcRow[col];
                 }
@@ -1092,17 +1193,18 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// Interlaced encoding the quantized (indexed, with palette) pixels.
     /// </summary>
     /// <typeparam name="TPixel">The type of the pixel.</typeparam>
+    /// <param name="frameControl">The frame control</param>
     /// <param name="quantized">The quantized.</param>
     /// <param name="deflateStream">The deflate stream.</param>
-    private void EncodeAdam7IndexedPixels<TPixel>(IndexedImageFrame<TPixel> quantized, ZlibDeflateStream deflateStream)
+    private void EncodeAdam7IndexedPixels<TPixel>(FrameControl frameControl, IndexedImageFrame<TPixel> quantized, ZlibDeflateStream deflateStream)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        int width = quantized.Width;
+        int width = (int)frameControl.Width;
-        int height = quantized.Height;
+        int endRow = (int)frameControl.YMax;
         for (int pass = 0; pass < 7; pass++)
         {
-            int startRow = Adam7.FirstRow[pass];
+            int startRow = Adam7.FirstRow[pass] + (int)frameControl.YOffset;
-            int startCol = Adam7.FirstColumn[pass];
+            int startCol = Adam7.FirstColumn[pass] + (int)frameControl.XOffset;
             int blockWidth = Adam7.ComputeBlockWidth(width, pass);
 
             int bytesPerScanline = this.bytesPerPixel <= 1
@@ -1121,17 +1223,16 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
             Span<byte> filter = filterBuffer.GetSpan();
             Span<byte> attempt = attemptBuffer.GetSpan();
 
-            for (int row = startRow;
+            for (int row = startRow; row < endRow; row += Adam7.RowIncrement[pass])
-                row < height;
-                row += Adam7.RowIncrement[pass])
             {
                 // Collect data
                 ReadOnlySpan<byte> srcRow = quantized.DangerousGetRowSpan(row);
                 for (int col = startCol, i = 0;
-                    col < width;
+                    col < frameControl.XMax;
                     col += Adam7.ColumnIncrement[pass])
                 {
-                    block[i++] = srcRow[col];
+                    block[i] = srcRow[col];
+                    i++;
                 }
 
                 // Encode data
@@ -1163,7 +1264,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// </summary>
     /// <param name="stream">The <see cref="Stream"/> to write to.</param>
     /// <param name="type">The type of chunk to write.</param>
-    /// <param name="data">The <see cref="T:byte[]"/> containing data.</param>
+    /// <param name="data">The <see cref="Span{Byte}"/> containing data.</param>
     /// <param name="offset">The position to offset the data at.</param>
     /// <param name="length">The of the data to write.</param>
     private void WriteChunk(Stream stream, PngChunkType type, Span<byte> data, int offset, int length)
@@ -1175,7 +1276,39 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
 
         stream.Write(buffer);
 
-        uint crc = Crc32.Calculate(buffer.Slice(4)); // Write the type buffer
+        uint crc = Crc32.Calculate(buffer[4..]); // Write the type buffer
+
+        if (data.Length > 0 && length > 0)
+        {
+            stream.Write(data, offset, length);
+
+            crc = Crc32.Calculate(crc, data.Slice(offset, length));
+        }
+
+        BinaryPrimitives.WriteUInt32BigEndian(buffer, crc);
+
+        stream.Write(buffer, 0, 4); // write the crc
+    }
+
+    /// <summary>
+    /// Writes a frame data chunk of a specified length to the stream at the given offset.
+    /// </summary>
+    /// <param name="stream">The <see cref="Stream"/> to write to.</param>
+    /// <param name="sequenceNumber">The frame sequence number.</param>
+    /// <param name="data">The <see cref="Span{Byte}"/> containing data.</param>
+    /// <param name="offset">The position to offset the data at.</param>
+    /// <param name="length">The of the data to write.</param>
+    private void WriteFrameDataChunk(Stream stream, uint sequenceNumber, Span<byte> data, int offset, int length)
+    {
+        Span<byte> buffer = stackalloc byte[12];
+
+        BinaryPrimitives.WriteInt32BigEndian(buffer, length + 4);
+        BinaryPrimitives.WriteUInt32BigEndian(buffer.Slice(4, 4), (uint)PngChunkType.FrameData);
+        BinaryPrimitives.WriteUInt32BigEndian(buffer.Slice(8, 4), sequenceNumber);
+
+        stream.Write(buffer);
+
+        uint crc = Crc32.Calculate(buffer[4..]); // Write the type buffer
 
         if (data.Length > 0 && length > 0)
         {
@@ -1198,7 +1331,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// </returns>
     private int CalculateScanlineLength(int width)
     {
-        int mod = this.bitDepth == 16 ? 16 : 8;
+        int mod = this.bitDepth is 16 ? 16 : 8;
         int scanlineLength = width * this.bitDepth * this.bytesPerPixel;
 
         int amount = scanlineLength % mod;
@@ -1242,14 +1375,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         if (!encoder.FilterMethod.HasValue)
         {
             // Specification recommends default filter method None for paletted images and Paeth for others.
-            if (this.colorType == PngColorType.Palette)
+            this.filterMethod = this.colorType is PngColorType.Palette ? PngFilterMethod.None : PngFilterMethod.Paeth;
-            {
-                this.filterMethod = PngFilterMethod.None;
-            }
-            else
-            {
-                this.filterMethod = PngFilterMethod.Paeth;
-            }
         }
 
         // Ensure bit depth and color type are a supported combination.
@@ -1265,7 +1391,7 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
         use16Bit = bits == (byte)PngBitDepth.Bit16;
         bytesPerPixel = CalculateBytesPerPixel(this.colorType, use16Bit);
 
-        this.interlaceMode = (encoder.InterlaceMethod ?? pngMetadata.InterlaceMethod).Value;
+        this.interlaceMode = (encoder.InterlaceMethod ?? pngMetadata.InterlaceMethod)!.Value;
         this.chunkFilter = encoder.SkipMetadata ? PngChunkFilter.ExcludeAll : encoder.ChunkFilter ?? PngChunkFilter.None;
     }
 
@@ -1276,28 +1402,50 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// <param name="encoder">The png encoder.</param>
     /// <param name="colorType">The color type.</param>
     /// <param name="bitDepth">The bits per component.</param>
-    /// <param name="image">The image.</param>
+    /// <param name="metadata">The image metadata.</param>
-    private static IndexedImageFrame<TPixel> CreateQuantizedFrame<TPixel>(
+    /// <param name="frame">The frame to quantize.</param>
+    /// <param name="previousPalette">Any previously derived palette.</param>
+    private IndexedImageFrame<TPixel>? CreateQuantizedFrame<TPixel>(
         QuantizingImageEncoder encoder,
         PngColorType colorType,
         byte bitDepth,
-        Image<TPixel> image)
+        PngMetadata metadata,
+        ImageFrame<TPixel> frame,
+        ReadOnlyMemory<TPixel>? previousPalette)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        if (colorType != PngColorType.Palette)
+        if (colorType is not PngColorType.Palette)
         {
             return null;
         }
 
+        if (previousPalette is not null)
+        {
+            // Use the previously derived palette created by quantizing the root frame to quantize the current frame.
+            using PaletteQuantizer<TPixel> paletteQuantizer = new(this.configuration, this.quantizer!.Options, previousPalette.Value, -1);
+            paletteQuantizer.BuildPalette(encoder.PixelSamplingStrategy, frame);
+            return paletteQuantizer.QuantizeFrame(frame, frame.Bounds());
+        }
+
         // Use the metadata to determine what quantization depth to use if no quantizer has been set.
-        IQuantizer quantizer = encoder.Quantizer
+        if (this.quantizer is null)
-            ?? new WuQuantizer(new QuantizerOptions { MaxColors = ColorNumerics.GetColorCountForBitDepth(bitDepth) });
+        {
+            if (metadata.ColorTable is not null)
+            {
+                // Use the provided palette. The caller is responsible for setting values.
+                this.quantizer = new PaletteQuantizer(metadata.ColorTable.Value);
+            }
+            else
+            {
+                this.quantizer = new WuQuantizer(new QuantizerOptions { MaxColors = ColorNumerics.GetColorCountForBitDepth(bitDepth) });
+            }
+        }
 
         // Create quantized frame returning the palette and set the bit depth.
-        using IQuantizer<TPixel> frameQuantizer = quantizer.CreatePixelSpecificQuantizer<TPixel>(image.GetConfiguration());
+        using IQuantizer<TPixel> frameQuantizer = this.quantizer.CreatePixelSpecificQuantizer<TPixel>(frame.Configuration);
 
-        frameQuantizer.BuildPalette(encoder.PixelSamplingStrategy, image);
+        frameQuantizer.BuildPalette(encoder.PixelSamplingStrategy, frame);
-        return frameQuantizer.QuantizeFrame(image.Frames.RootFrame, image.Bounds);
+        return frameQuantizer.QuantizeFrame(frame, frame.Bounds());
     }
 
     /// <summary>
@@ -1311,25 +1459,23 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     private static byte CalculateBitDepth<TPixel>(
         PngColorType colorType,
         byte bitDepth,
-        IndexedImageFrame<TPixel> quantizedFrame)
+        IndexedImageFrame<TPixel>? quantizedFrame)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        if (colorType == PngColorType.Palette)
+        if (colorType is PngColorType.Palette)
         {
-            byte quantizedBits = (byte)Numerics.Clamp(ColorNumerics.GetBitsNeededForColorDepth(quantizedFrame.Palette.Length), 1, 8);
+            byte quantizedBits = (byte)Numerics.Clamp(ColorNumerics.GetBitsNeededForColorDepth(quantizedFrame!.Palette.Length), 1, 8);
             byte bits = Math.Max(bitDepth, quantizedBits);
 
             // Png only supports in four pixel depths: 1, 2, 4, and 8 bits when using the PLTE chunk
             // We check again for the bit depth as the bit depth of the color palette from a given quantizer might not
             // be within the acceptable range.
-            if (bits == 3)
+            bits = bits switch
             {
-                bits = 4;
+                3 => 4,
-            }
+                >= 5 and <= 7 => 8,
-            else if (bits is >= 5 and <= 7)
+                _ => bits
-            {
+            };
-                bits = 8;
-            }
 
             bitDepth = bits;
         }
@@ -1367,21 +1513,21 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// <typeparam name="TPixel">The type of pixel format.</typeparam>
     private static PngColorType SuggestColorType<TPixel>()
         where TPixel : unmanaged, IPixel<TPixel>
-        => typeof(TPixel) switch
+        => default(TPixel) switch
         {
-            Type t when t == typeof(A8) => PngColorType.GrayscaleWithAlpha,
+            A8 => PngColorType.GrayscaleWithAlpha,
-            Type t when t == typeof(Argb32) => PngColorType.RgbWithAlpha,
+            Argb32 => PngColorType.RgbWithAlpha,
-            Type t when t == typeof(Bgr24) => PngColorType.Rgb,
+            Bgr24 => PngColorType.Rgb,
-            Type t when t == typeof(Bgra32) => PngColorType.RgbWithAlpha,
+            Bgra32 => PngColorType.RgbWithAlpha,
-            Type t when t == typeof(L8) => PngColorType.Grayscale,
+            L8 => PngColorType.Grayscale,
-            Type t when t == typeof(L16) => PngColorType.Grayscale,
+            L16 => PngColorType.Grayscale,
-            Type t when t == typeof(La16) => PngColorType.GrayscaleWithAlpha,
+            La16 => PngColorType.GrayscaleWithAlpha,
-            Type t when t == typeof(La32) => PngColorType.GrayscaleWithAlpha,
+            La32 => PngColorType.GrayscaleWithAlpha,
-            Type t when t == typeof(Rgb24) => PngColorType.Rgb,
+            Rgb24 => PngColorType.Rgb,
-            Type t when t == typeof(Rgba32) => PngColorType.RgbWithAlpha,
+            Rgba32 => PngColorType.RgbWithAlpha,
-            Type t when t == typeof(Rgb48) => PngColorType.Rgb,
+            Rgb48 => PngColorType.Rgb,
-            Type t when t == typeof(Rgba64) => PngColorType.RgbWithAlpha,
+            Rgba64 => PngColorType.RgbWithAlpha,
-            Type t when t == typeof(RgbaVector) => PngColorType.RgbWithAlpha,
+            RgbaVector => PngColorType.RgbWithAlpha,
             _ => PngColorType.RgbWithAlpha
         };
 
@@ -1392,27 +1538,27 @@ internal sealed class PngEncoderCore : IImageEncoderInternals, IDisposable
     /// <typeparam name="TPixel">The type of pixel format.</typeparam>
     private static PngBitDepth SuggestBitDepth<TPixel>()
         where TPixel : unmanaged, IPixel<TPixel>
-        => typeof(TPixel) switch
+        => default(TPixel) switch
         {
-            Type t when t == typeof(A8) => PngBitDepth.Bit8,
+            A8 => PngBitDepth.Bit8,
-            Type t when t == typeof(Argb32) => PngBitDepth.Bit8,
+            Argb32 => PngBitDepth.Bit8,
-            Type t when t == typeof(Bgr24) => PngBitDepth.Bit8,
+            Bgr24 => PngBitDepth.Bit8,
-            Type t when t == typeof(Bgra32) => PngBitDepth.Bit8,
+            Bgra32 => PngBitDepth.Bit8,
-            Type t when t == typeof(L8) => PngBitDepth.Bit8,
+            L8 => PngBitDepth.Bit8,
-            Type t when t == typeof(L16) => PngBitDepth.Bit16,
+            L16 => PngBitDepth.Bit16,
-            Type t when t == typeof(La16) => PngBitDepth.Bit8,
+            La16 => PngBitDepth.Bit8,
-            Type t when t == typeof(La32) => PngBitDepth.Bit16,
+            La32 => PngBitDepth.Bit16,
-            Type t when t == typeof(Rgb24) => PngBitDepth.Bit8,
+            Rgb24 => PngBitDepth.Bit8,
-            Type t when t == typeof(Rgba32) => PngBitDepth.Bit8,
+            Rgba32 => PngBitDepth.Bit8,
-            Type t when t == typeof(Rgb48) => PngBitDepth.Bit16,
+            Rgb48 => PngBitDepth.Bit16,
-            Type t when t == typeof(Rgba64) => PngBitDepth.Bit16,
+            Rgba64 => PngBitDepth.Bit16,
-            Type t when t == typeof(RgbaVector) => PngBitDepth.Bit16,
+            RgbaVector => PngBitDepth.Bit16,
             _ => PngBitDepth.Bit8
         };
 
     private unsafe struct ScratchBuffer
     {
-        private const int Size = 16;
+        private const int Size = 26;
         private fixed byte scratch[Size];
 
         public Span<byte> Span => MemoryMarshal.CreateSpan(ref this.scratch[0], Size);

src/ImageSharp/Formats/Png/PngFormat.cs

@@ -6,7 +6,7 @@ namespace SixLabors.ImageSharp.Formats.Png;
 /// <summary>
 /// Registers the image encoders, decoders and mime type detectors for the png format.
 /// </summary>
-public sealed class PngFormat : IImageFormat<PngMetadata>
+public sealed class PngFormat : IImageFormat<PngMetadata, PngFrameMetadata>
 {
     private PngFormat()
     {
@@ -31,4 +31,7 @@ public sealed class PngFormat : IImageFormat<PngMetadata>
 
     /// <inheritdoc/>
     public PngMetadata CreateDefaultFormatMetadata() => new();
+
+    /// <inheritdoc/>
+    public PngFrameMetadata CreateDefaultFormatFrameMetadata() => new();
 }

src/ImageSharp/Formats/Png/PngFrameMetadata.cs

@@ -0,0 +1,62 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Formats.Png.Chunks;
+
+namespace SixLabors.ImageSharp.Formats.Png;
+
+/// <summary>
+/// Provides APng specific metadata information for the image frame.
+/// </summary>
+public class PngFrameMetadata : IDeepCloneable
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="PngFrameMetadata"/> class.
+    /// </summary>
+    public PngFrameMetadata()
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="PngFrameMetadata"/> class.
+    /// </summary>
+    /// <param name="other">The metadata to create an instance from.</param>
+    private PngFrameMetadata(PngFrameMetadata other)
+    {
+        this.FrameDelay = other.FrameDelay;
+        this.DisposalMethod = other.DisposalMethod;
+        this.BlendMethod = other.BlendMethod;
+    }
+
+    /// <summary>
+    /// Gets or sets the frame delay for animated images.
+    /// If not 0, when utilized in Png animation, this field specifies the number of hundredths (1/100) of a second to
+    /// wait before continuing with the processing of the Data Stream.
+    /// The clock starts ticking immediately after the graphic is rendered.
+    /// </summary>
+    public Rational FrameDelay { get; set; }
+
+    /// <summary>
+    /// Gets or sets the type of frame area disposal to be done after rendering this frame
+    /// </summary>
+    public PngDisposalMethod DisposalMethod { get; set; }
+
+    /// <summary>
+    /// Gets or sets the type of frame area rendering for this frame
+    /// </summary>
+    public PngBlendMethod BlendMethod { get; set; }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="PngFrameMetadata"/> class.
+    /// </summary>
+    /// <param name="frameControl">The chunk to create an instance from.</param>
+    internal void FromChunk(in FrameControl frameControl)
+    {
+        this.FrameDelay = new Rational(frameControl.DelayNumerator, frameControl.DelayDenominator);
+        this.DisposalMethod = frameControl.DisposeOperation;
+        this.BlendMethod = frameControl.BlendOperation;
+    }
+
+    /// <inheritdoc/>
+    public IDeepCloneable DeepClone() => new PngFrameMetadata(this);
+}

src/ImageSharp/Formats/Png/PngMetadata.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using SixLabors.ImageSharp.Formats.Png.Chunks;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats.Png;
@@ -27,11 +28,13 @@ public class PngMetadata : IDeepCloneable
         this.ColorType = other.ColorType;
         this.Gamma = other.Gamma;
         this.InterlaceMethod = other.InterlaceMethod;
-        this.HasTransparency = other.HasTransparency;
+        this.TransparentColor = other.TransparentColor;
-        this.TransparentL8 = other.TransparentL8;
+        this.RepeatCount = other.RepeatCount;
-        this.TransparentL16 = other.TransparentL16;
+
-        this.TransparentRgb24 = other.TransparentRgb24;
+        if (other.ColorTable?.Length > 0)
-        this.TransparentRgb48 = other.TransparentRgb48;
+        {
+            this.ColorTable = other.ColorTable.Value.ToArray();
+        }
 
         for (int i = 0; i < other.TextData.Count; i++)
         {
@@ -61,33 +64,14 @@ public class PngMetadata : IDeepCloneable
     public float Gamma { get; set; }
 
     /// <summary>
-    /// Gets or sets the Rgb24 transparent color.
+    /// Gets or sets the color table, if any.
-    /// This represents any color in an 8 bit Rgb24 encoded png that should be transparent.
-    /// </summary>
-    public Rgb24? TransparentRgb24 { get; set; }
-
-    /// <summary>
-    /// Gets or sets the Rgb48 transparent color.
-    /// This represents any color in a 16 bit Rgb24 encoded png that should be transparent.
     /// </summary>
-    public Rgb48? TransparentRgb48 { get; set; }
+    public ReadOnlyMemory<Color>? ColorTable { get; set; }
 
     /// <summary>
-    /// Gets or sets the 8 bit grayscale transparent color.
+    /// Gets or sets the transparent color used with non palette based images, if a transparency chunk and markers were decoded.
-    /// This represents any color in an 8 bit grayscale encoded png that should be transparent.
     /// </summary>
-    public L8? TransparentL8 { get; set; }
+    public Color? TransparentColor { get; set; }
-
-    /// <summary>
-    /// Gets or sets the 16 bit grayscale transparent color.
-    /// This represents any color in a 16 bit grayscale encoded png that should be transparent.
-    /// </summary>
-    public L16? TransparentL16 { get; set; }
-
-    /// <summary>
-    /// Gets or sets a value indicating whether the image contains a transparency chunk and markers were decoded.
-    /// </summary>
-    public bool HasTransparency { get; set; }
 
     /// <summary>
     /// Gets or sets the collection of text data stored within the iTXt, tEXt, and zTXt chunks.
@@ -95,6 +79,11 @@ public class PngMetadata : IDeepCloneable
     /// </summary>
     public IList<PngTextData> TextData { get; set; } = new List<PngTextData>();
 
+    /// <summary>
+    /// Gets or sets the number of times to loop this APNG.  0 indicates infinite looping.
+    /// </summary>
+    public int RepeatCount { get; set; }
+
     /// <inheritdoc/>
     public IDeepCloneable DeepClone() => new PngMetadata(this);
 }

src/ImageSharp/Formats/Png/PngScanlineProcessor.cs

@@ -4,6 +4,7 @@
 using System.Buffers.Binary;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
+using SixLabors.ImageSharp.Formats.Png.Chunks;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats.Png;
@@ -15,96 +16,43 @@ namespace SixLabors.ImageSharp.Formats.Png;
 internal static class PngScanlineProcessor
 {
     public static void ProcessGrayscaleScanline<TPixel>(
-        in PngHeader header,
+        int bitDepth,
+        in FrameControl frameControl,
         ReadOnlySpan<byte> scanlineSpan,
         Span<TPixel> rowSpan,
-        bool hasTrans,
+        Color? transparentColor)
-        L16 luminance16Trans,
+        where TPixel : unmanaged, IPixel<TPixel> =>
-        L8 luminanceTrans)
+        ProcessInterlacedGrayscaleScanline(
-        where TPixel : unmanaged, IPixel<TPixel>
+            bitDepth,
-    {
+            frameControl,
-        TPixel pixel = default;
+            scanlineSpan,
-        ref byte scanlineSpanRef = ref MemoryMarshal.GetReference(scanlineSpan);
+            rowSpan,
-        ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
+            0,
-        int scaleFactor = 255 / (ColorNumerics.GetColorCountForBitDepth(header.BitDepth) - 1);
+            1,
-
+            transparentColor);
-        if (!hasTrans)
-        {
-            if (header.BitDepth == 16)
-            {
-                int o = 0;
-                for (nuint x = 0; x < (uint)header.Width; x++, o += 2)
-                {
-                    ushort luminance = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, 2));
-                    pixel.FromL16(Unsafe.As<ushort, L16>(ref luminance));
-                    Unsafe.Add(ref rowSpanRef, x) = pixel;
-                }
-            }
-            else
-            {
-                for (nuint x = 0; x < (uint)header.Width; x++)
-                {
-                    byte luminance = (byte)(Unsafe.Add(ref scanlineSpanRef, x) * scaleFactor);
-                    pixel.FromL8(Unsafe.As<byte, L8>(ref luminance));
-                    Unsafe.Add(ref rowSpanRef, x) = pixel;
-                }
-            }
-
-            return;
-        }
-
-        if (header.BitDepth == 16)
-        {
-            La32 source = default;
-            int o = 0;
-            for (nuint x = 0; x < (uint)header.Width; x++, o += 2)
-            {
-                ushort luminance = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, 2));
-                source.L = luminance;
-                source.A = luminance.Equals(luminance16Trans.PackedValue) ? ushort.MinValue : ushort.MaxValue;
-
-                pixel.FromLa32(source);
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
-        }
-        else
-        {
-            La16 source = default;
-            byte scaledLuminanceTrans = (byte)(luminanceTrans.PackedValue * scaleFactor);
-            for (nuint x = 0; x < (uint)header.Width; x++)
-            {
-                byte luminance = (byte)(Unsafe.Add(ref scanlineSpanRef, x) * scaleFactor);
-                source.L = luminance;
-                source.A = luminance.Equals(scaledLuminanceTrans) ? byte.MinValue : byte.MaxValue;
-
-                pixel.FromLa16(source);
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
-        }
-    }
 
     public static void ProcessInterlacedGrayscaleScanline<TPixel>(
-        in PngHeader header,
+        int bitDepth,
+        in FrameControl frameControl,
         ReadOnlySpan<byte> scanlineSpan,
         Span<TPixel> rowSpan,
         uint pixelOffset,
         uint increment,
-        bool hasTrans,
+        Color? transparentColor)
-        L16 luminance16Trans,
-        L8 luminanceTrans)
         where TPixel : unmanaged, IPixel<TPixel>
     {
+        uint offset = pixelOffset + frameControl.XOffset;
         TPixel pixel = default;
         ref byte scanlineSpanRef = ref MemoryMarshal.GetReference(scanlineSpan);
         ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
-        int scaleFactor = 255 / (ColorNumerics.GetColorCountForBitDepth(header.BitDepth) - 1);
+        int scaleFactor = 255 / (ColorNumerics.GetColorCountForBitDepth(bitDepth) - 1);
 
-        if (!hasTrans)
+        if (transparentColor is null)
         {
-            if (header.BitDepth == 16)
+            if (bitDepth == 16)
             {
                 int o = 0;
-                for (nuint x = pixelOffset; x < (uint)header.Width; x += increment, o += 2)
+                for (nuint x = offset; x < frameControl.XMax; x += increment, o += 2)
                 {
                     ushort luminance = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, 2));
                     pixel.FromL16(Unsafe.As<ushort, L16>(ref luminance));
@@ -113,7 +61,7 @@ internal static class PngScanlineProcessor
             }
             else
             {
-                for (nuint x = pixelOffset, o = 0; x < (uint)header.Width; x += increment, o++)
+                for (nuint x = offset, o = 0; x < frameControl.XMax; x += increment, o++)
                 {
                     byte luminance = (byte)(Unsafe.Add(ref scanlineSpanRef, o) * scaleFactor);
                     pixel.FromL8(Unsafe.As<byte, L8>(ref luminance));
@@ -124,15 +72,16 @@ internal static class PngScanlineProcessor
             return;
         }
 
-        if (header.BitDepth == 16)
+        if (bitDepth == 16)
         {
+            L16 transparent = transparentColor.Value.ToPixel<L16>();
             La32 source = default;
             int o = 0;
-            for (nuint x = pixelOffset; x < (uint)header.Width; x += increment, o += 2)
+            for (nuint x = offset; x < frameControl.XMax; x += increment, o += 2)
             {
                 ushort luminance = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, 2));
                 source.L = luminance;
-                source.A = luminance.Equals(luminance16Trans.PackedValue) ? ushort.MinValue : ushort.MaxValue;
+                source.A = luminance.Equals(transparent.PackedValue) ? ushort.MinValue : ushort.MaxValue;
 
                 pixel.FromLa32(source);
                 Unsafe.Add(ref rowSpanRef, x) = pixel;
@@ -140,13 +89,13 @@ internal static class PngScanlineProcessor
         }
         else
         {
+            byte transparent = (byte)(transparentColor.Value.ToPixel<L8>().PackedValue * scaleFactor);
             La16 source = default;
-            byte scaledLuminanceTrans = (byte)(luminanceTrans.PackedValue * scaleFactor);
+            for (nuint x = offset, o = 0; x < frameControl.XMax; x += increment, o++)
-            for (nuint x = pixelOffset, o = 0; x < (uint)header.Width; x += increment, o++)
             {
                 byte luminance = (byte)(Unsafe.Add(ref scanlineSpanRef, o) * scaleFactor);
                 source.L = luminance;
-                source.A = luminance.Equals(scaledLuminanceTrans) ? byte.MinValue : byte.MaxValue;
+                source.A = luminance.Equals(transparent) ? byte.MinValue : byte.MaxValue;
 
                 pixel.FromLa16(source);
                 Unsafe.Add(ref rowSpanRef, x) = pixel;
@@ -155,47 +104,26 @@ internal static class PngScanlineProcessor
     }
 
     public static void ProcessGrayscaleWithAlphaScanline<TPixel>(
-        in PngHeader header,
+        int bitDepth,
+        in FrameControl frameControl,
         ReadOnlySpan<byte> scanlineSpan,
         Span<TPixel> rowSpan,
         uint bytesPerPixel,
         uint bytesPerSample)
-        where TPixel : unmanaged, IPixel<TPixel>
+        where TPixel : unmanaged, IPixel<TPixel> =>
-    {
+        ProcessInterlacedGrayscaleWithAlphaScanline(
-        TPixel pixel = default;
+            bitDepth,
-        ref byte scanlineSpanRef = ref MemoryMarshal.GetReference(scanlineSpan);
+            frameControl,
-        ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
+            scanlineSpan,
-
+            rowSpan,
-        if (header.BitDepth == 16)
+            0,
-        {
+            1,
-            La32 source = default;
+            bytesPerPixel,
-            int o = 0;
+            bytesPerSample);
-            for (nuint x = 0; x < (uint)header.Width; x++, o += 4)
-            {
-                source.L = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, 2));
-                source.A = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + 2, 2));
-
-                pixel.FromLa32(source);
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
-        }
-        else
-        {
-            La16 source = default;
-            for (nuint x = 0; x < (uint)header.Width; x++)
-            {
-                nuint offset = x * bytesPerPixel;
-                source.L = Unsafe.Add(ref scanlineSpanRef, offset);
-                source.A = Unsafe.Add(ref scanlineSpanRef, offset + bytesPerSample);
-
-                pixel.FromLa16(source);
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
-        }
-    }
 
     public static void ProcessInterlacedGrayscaleWithAlphaScanline<TPixel>(
-        in PngHeader header,
+        int bitDepth,
+        in FrameControl frameControl,
         ReadOnlySpan<byte> scanlineSpan,
         Span<TPixel> rowSpan,
         uint pixelOffset,
@@ -204,15 +132,16 @@ internal static class PngScanlineProcessor
         uint bytesPerSample)
         where TPixel : unmanaged, IPixel<TPixel>
     {
+        uint offset = pixelOffset + frameControl.XOffset;
         TPixel pixel = default;
         ref byte scanlineSpanRef = ref MemoryMarshal.GetReference(scanlineSpan);
         ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
 
-        if (header.BitDepth == 16)
+        if (bitDepth == 16)
         {
             La32 source = default;
             int o = 0;
-            for (nuint x = pixelOffset; x < (uint)header.Width; x += increment, o += 4)
+            for (nuint x = offset; x < frameControl.XMax; x += increment, o += 4)
             {
                 source.L = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, 2));
                 source.A = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + 2, 2));
@@ -224,135 +153,108 @@ internal static class PngScanlineProcessor
         else
         {
             La16 source = default;
-            nuint offset = 0;
+            nuint offset2 = 0;
-            for (nuint x = pixelOffset; x < (uint)header.Width; x += increment)
+            for (nuint x = offset; x < frameControl.XMax; x += increment)
             {
-                source.L = Unsafe.Add(ref scanlineSpanRef, offset);
+                source.L = Unsafe.Add(ref scanlineSpanRef, offset2);
-                source.A = Unsafe.Add(ref scanlineSpanRef, offset + bytesPerSample);
+                source.A = Unsafe.Add(ref scanlineSpanRef, offset2 + bytesPerSample);
 
                 pixel.FromLa16(source);
                 Unsafe.Add(ref rowSpanRef, x) = pixel;
-                offset += bytesPerPixel;
+                offset2 += bytesPerPixel;
             }
         }
     }
 
     public static void ProcessPaletteScanline<TPixel>(
-        in PngHeader header,
+        in FrameControl frameControl,
         ReadOnlySpan<byte> scanlineSpan,
         Span<TPixel> rowSpan,
-        ReadOnlySpan<byte> palette,
+        ReadOnlyMemory<Color>? palette)
-        byte[] paletteAlpha)
+        where TPixel : unmanaged, IPixel<TPixel> =>
-        where TPixel : unmanaged, IPixel<TPixel>
+        ProcessInterlacedPaletteScanline(
-    {
+            frameControl,
-        if (palette.IsEmpty)
+            scanlineSpan,
-        {
+            rowSpan,
-            PngThrowHelper.ThrowMissingPalette();
+            0,
-        }
+            1,
-
+            palette);
-        TPixel pixel = default;
-        ref byte scanlineSpanRef = ref MemoryMarshal.GetReference(scanlineSpan);
-        ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
-        ReadOnlySpan<Rgb24> palettePixels = MemoryMarshal.Cast<byte, Rgb24>(palette);
-        ref Rgb24 palettePixelsRef = ref MemoryMarshal.GetReference(palettePixels);
-
-        if (paletteAlpha?.Length > 0)
-        {
-            // If the alpha palette is not null and has one or more entries, this means, that the image contains an alpha
-            // channel and we should try to read it.
-            Rgba32 rgba = default;
-            ref byte paletteAlphaRef = ref MemoryMarshal.GetArrayDataReference(paletteAlpha);
-
-            for (nuint x = 0; x < (uint)header.Width; x++)
-            {
-                uint index = Unsafe.Add(ref scanlineSpanRef, x);
-                rgba.Rgb = Unsafe.Add(ref palettePixelsRef, index);
-                rgba.A = paletteAlpha.Length > index ? Unsafe.Add(ref paletteAlphaRef, index) : byte.MaxValue;
-
-                pixel.FromRgba32(rgba);
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
-        }
-        else
-        {
-            for (nuint x = 0; x < (uint)header.Width; x++)
-            {
-                int index = Unsafe.Add(ref scanlineSpanRef, x);
-                Rgb24 rgb = Unsafe.Add(ref palettePixelsRef, index);
-
-                pixel.FromRgb24(rgb);
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
-        }
-    }
 
     public static void ProcessInterlacedPaletteScanline<TPixel>(
-        in PngHeader header,
+        in FrameControl frameControl,
         ReadOnlySpan<byte> scanlineSpan,
         Span<TPixel> rowSpan,
         uint pixelOffset,
         uint increment,
-        ReadOnlySpan<byte> palette,
+        ReadOnlyMemory<Color>? palette)
-        byte[] paletteAlpha)
         where TPixel : unmanaged, IPixel<TPixel>
     {
+        if (palette is null)
+        {
+            PngThrowHelper.ThrowMissingPalette();
+        }
+
         TPixel pixel = default;
         ref byte scanlineSpanRef = ref MemoryMarshal.GetReference(scanlineSpan);
         ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
-        ReadOnlySpan<Rgb24> palettePixels = MemoryMarshal.Cast<byte, Rgb24>(palette);
+        ref Color paletteBase = ref MemoryMarshal.GetReference(palette.Value.Span);
-        ref Rgb24 palettePixelsRef = ref MemoryMarshal.GetReference(palettePixels);
-
-        if (paletteAlpha?.Length > 0)
-        {
-            // If the alpha palette is not null and has one or more entries, this means, that the image contains an alpha
-            // channel and we should try to read it.
-            Rgba32 rgba = default;
-            ref byte paletteAlphaRef = ref MemoryMarshal.GetArrayDataReference(paletteAlpha);
-            for (nuint x = pixelOffset, o = 0; x < (uint)header.Width; x += increment, o++)
-            {
-                uint index = Unsafe.Add(ref scanlineSpanRef, o);
-                rgba.A = paletteAlpha.Length > index ? Unsafe.Add(ref paletteAlphaRef, index) : byte.MaxValue;
-                rgba.Rgb = Unsafe.Add(ref palettePixelsRef, index);
 
-                pixel.FromRgba32(rgba);
+        for (nuint x = pixelOffset, o = 0; x < frameControl.XMax; x += increment, o++)
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
-        }
-        else
         {
-            for (nuint x = pixelOffset, o = 0; x < (uint)header.Width; x += increment, o++)
+            uint index = Unsafe.Add(ref scanlineSpanRef, o);
-            {
+            pixel.FromRgba32(Unsafe.Add(ref paletteBase, index).ToRgba32());
-                int index = Unsafe.Add(ref scanlineSpanRef, o);
+            Unsafe.Add(ref rowSpanRef, x) = pixel;
-                Rgb24 rgb = Unsafe.Add(ref palettePixelsRef, index);
-
-                pixel.FromRgb24(rgb);
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
         }
     }
 
     public static void ProcessRgbScanline<TPixel>(
         Configuration configuration,
-        in PngHeader header,
+        int bitDepth,
+        in FrameControl frameControl,
+        ReadOnlySpan<byte> scanlineSpan,
+        Span<TPixel> rowSpan,
+        int bytesPerPixel,
+        int bytesPerSample,
+        Color? transparentColor)
+       where TPixel : unmanaged, IPixel<TPixel> =>
+       ProcessInterlacedRgbScanline(
+           configuration,
+           bitDepth,
+           frameControl,
+           scanlineSpan,
+           rowSpan,
+           0,
+           1,
+           bytesPerPixel,
+           bytesPerSample,
+           transparentColor);
+
+    public static void ProcessInterlacedRgbScanline<TPixel>(
+        Configuration configuration,
+        int bitDepth,
+        in FrameControl frameControl,
         ReadOnlySpan<byte> scanlineSpan,
         Span<TPixel> rowSpan,
+        uint pixelOffset,
+        uint increment,
         int bytesPerPixel,
         int bytesPerSample,
-        bool hasTrans,
+        Color? transparentColor)
-        Rgb48 rgb48Trans,
-        Rgb24 rgb24Trans)
         where TPixel : unmanaged, IPixel<TPixel>
     {
+        uint offset = pixelOffset + frameControl.XOffset;
+
         TPixel pixel = default;
+        ref byte scanlineSpanRef = ref MemoryMarshal.GetReference(scanlineSpan);
         ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
 
-        if (!hasTrans)
+        if (transparentColor is null)
         {
-            if (header.BitDepth == 16)
+            if (bitDepth == 16)
             {
                 Rgb48 rgb48 = default;
                 int o = 0;
-                for (nuint x = 0; x < (uint)header.Width; x++, o += bytesPerPixel)
+                for (nuint x = offset; x < frameControl.XMax; x += increment, o += bytesPerPixel)
                 {
                     rgb48.R = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, bytesPerSample));
                     rgb48.G = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + bytesPerSample, bytesPerSample));
@@ -362,27 +264,47 @@ internal static class PngScanlineProcessor
                     Unsafe.Add(ref rowSpanRef, x) = pixel;
                 }
             }
+            else if (pixelOffset == 0 && increment == 1)
+            {
+                PixelOperations<TPixel>.Instance.FromRgb24Bytes(
+                    configuration,
+                    scanlineSpan[..(int)(frameControl.Width * bytesPerPixel)],
+                    rowSpan.Slice((int)frameControl.XOffset, (int)frameControl.Width),
+                    (int)frameControl.Width);
+            }
             else
             {
-                PixelOperations<TPixel>.Instance.FromRgb24Bytes(configuration, scanlineSpan, rowSpan, header.Width);
+                Rgb24 rgb = default;
+                int o = 0;
+                for (nuint x = offset; x < frameControl.XMax; x += increment, o += bytesPerPixel)
+                {
+                    rgb.R = Unsafe.Add(ref scanlineSpanRef, (uint)o);
+                    rgb.G = Unsafe.Add(ref scanlineSpanRef, (uint)(o + bytesPerSample));
+                    rgb.B = Unsafe.Add(ref scanlineSpanRef, (uint)(o + (2 * bytesPerSample)));
+
+                    pixel.FromRgb24(rgb);
+                    Unsafe.Add(ref rowSpanRef, x) = pixel;
+                }
             }
 
             return;
         }
 
-        if (header.BitDepth == 16)
+        if (bitDepth == 16)
         {
+            Rgb48 transparent = transparentColor.Value.ToPixel<Rgb48>();
+
             Rgb48 rgb48 = default;
             Rgba64 rgba64 = default;
             int o = 0;
-            for (nuint x = 0; x < (uint)header.Width; x++, o += bytesPerPixel)
+            for (nuint x = offset; x < frameControl.XMax; x += increment, o += bytesPerPixel)
             {
                 rgb48.R = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, bytesPerSample));
                 rgb48.G = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + bytesPerSample, bytesPerSample));
                 rgb48.B = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + (2 * bytesPerSample), bytesPerSample));
 
                 rgba64.Rgb = rgb48;
-                rgba64.A = rgb48.Equals(rgb48Trans) ? ushort.MinValue : ushort.MaxValue;
+                rgba64.A = rgb48.Equals(transparent) ? ushort.MinValue : ushort.MaxValue;
 
                 pixel.FromRgba64(rgba64);
                 Unsafe.Add(ref rowSpanRef, x) = pixel;
@@ -390,142 +312,47 @@ internal static class PngScanlineProcessor
         }
         else
         {
-            Rgba32 rgba32 = default;
+            Rgb24 transparent = transparentColor.Value.ToPixel<Rgb24>();
-            ReadOnlySpan<Rgb24> rgb24Span = MemoryMarshal.Cast<byte, Rgb24>(scanlineSpan);
-            ref Rgb24 rgb24SpanRef = ref MemoryMarshal.GetReference(rgb24Span);
-            for (nuint x = 0; x < (uint)header.Width; x++)
-            {
-                ref readonly Rgb24 rgb24 = ref Unsafe.Add(ref rgb24SpanRef, x);
-                rgba32.Rgb = rgb24;
-                rgba32.A = rgb24.Equals(rgb24Trans) ? byte.MinValue : byte.MaxValue;
-
-                pixel.FromRgba32(rgba32);
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
-        }
-    }
-
-    public static void ProcessInterlacedRgbScanline<TPixel>(
-        in PngHeader header,
-        ReadOnlySpan<byte> scanlineSpan,
-        Span<TPixel> rowSpan,
-        uint pixelOffset,
-        uint increment,
-        int bytesPerPixel,
-        int bytesPerSample,
-        bool hasTrans,
-        Rgb48 rgb48Trans,
-        Rgb24 rgb24Trans)
-        where TPixel : unmanaged, IPixel<TPixel>
-    {
-        TPixel pixel = default;
-        ref byte scanlineSpanRef = ref MemoryMarshal.GetReference(scanlineSpan);
-        ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
-
-        if (header.BitDepth == 16)
-        {
-            if (hasTrans)
-            {
-                Rgb48 rgb48 = default;
-                Rgba64 rgba64 = default;
-                int o = 0;
-                for (nuint x = pixelOffset; x < (uint)header.Width; x += increment, o += bytesPerPixel)
-                {
-                    rgb48.R = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, bytesPerSample));
-                    rgb48.G = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + bytesPerSample, bytesPerSample));
-                    rgb48.B = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + (2 * bytesPerSample), bytesPerSample));
-
-                    rgba64.Rgb = rgb48;
-                    rgba64.A = rgb48.Equals(rgb48Trans) ? ushort.MinValue : ushort.MaxValue;
 
-                    pixel.FromRgba64(rgba64);
-                    Unsafe.Add(ref rowSpanRef, x) = pixel;
-                }
-            }
-            else
-            {
-                Rgb48 rgb48 = default;
-                int o = 0;
-                for (nuint x = pixelOffset; x < (uint)header.Width; x += increment, o += bytesPerPixel)
-                {
-                    rgb48.R = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, bytesPerSample));
-                    rgb48.G = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + bytesPerSample, bytesPerSample));
-                    rgb48.B = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + (2 * bytesPerSample), bytesPerSample));
-
-                    pixel.FromRgb48(rgb48);
-                    Unsafe.Add(ref rowSpanRef, x) = pixel;
-                }
-            }
-
-            return;
-        }
-
-        if (hasTrans)
-        {
             Rgba32 rgba = default;
             int o = 0;
-            for (nuint x = pixelOffset; x < (uint)header.Width; x += increment, o += bytesPerPixel)
+            for (nuint x = offset; x < frameControl.XMax; x += increment, o += bytesPerPixel)
             {
                 rgba.R = Unsafe.Add(ref scanlineSpanRef, (uint)o);
                 rgba.G = Unsafe.Add(ref scanlineSpanRef, (uint)(o + bytesPerSample));
                 rgba.B = Unsafe.Add(ref scanlineSpanRef, (uint)(o + (2 * bytesPerSample)));
-                rgba.A = rgb24Trans.Equals(rgba.Rgb) ? byte.MinValue : byte.MaxValue;
+                rgba.A = transparent.Equals(rgba.Rgb) ? byte.MinValue : byte.MaxValue;
 
                 pixel.FromRgba32(rgba);
                 Unsafe.Add(ref rowSpanRef, x) = pixel;
             }
         }
-        else
-        {
-            Rgb24 rgb = default;
-            int o = 0;
-            for (nuint x = pixelOffset; x < (uint)header.Width; x += increment, o += bytesPerPixel)
-            {
-                rgb.R = Unsafe.Add(ref scanlineSpanRef, (uint)o);
-                rgb.G = Unsafe.Add(ref scanlineSpanRef, (uint)(o + bytesPerSample));
-                rgb.B = Unsafe.Add(ref scanlineSpanRef, (uint)(o + (2 * bytesPerSample)));
-
-                pixel.FromRgb24(rgb);
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
-        }
     }
 
     public static void ProcessRgbaScanline<TPixel>(
         Configuration configuration,
-        in PngHeader header,
+        int bitDepth,
+        in FrameControl frameControl,
         ReadOnlySpan<byte> scanlineSpan,
         Span<TPixel> rowSpan,
         int bytesPerPixel,
         int bytesPerSample)
-        where TPixel : unmanaged, IPixel<TPixel>
+       where TPixel : unmanaged, IPixel<TPixel> =>
-    {
+       ProcessInterlacedRgbaScanline(
-        TPixel pixel = default;
+           configuration,
-        ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
+           bitDepth,
-
+           frameControl,
-        if (header.BitDepth == 16)
+           scanlineSpan,
-        {
+           rowSpan,
-            Rgba64 rgba64 = default;
+           0,
-            int o = 0;
+           1,
-            for (nuint x = 0; x < (uint)header.Width; x++, o += bytesPerPixel)
+           bytesPerPixel,
-            {
+           bytesPerSample);
-                rgba64.R = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, bytesPerSample));
-                rgba64.G = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + bytesPerSample, bytesPerSample));
-                rgba64.B = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + (2 * bytesPerSample), bytesPerSample));
-                rgba64.A = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + (3 * bytesPerSample), bytesPerSample));
-
-                pixel.FromRgba64(rgba64);
-                Unsafe.Add(ref rowSpanRef, x) = pixel;
-            }
-        }
-        else
-        {
-            PixelOperations<TPixel>.Instance.FromRgba32Bytes(configuration, scanlineSpan, rowSpan, header.Width);
-        }
-    }
 
     public static void ProcessInterlacedRgbaScanline<TPixel>(
-        in PngHeader header,
+        Configuration configuration,
+        int bitDepth,
+        in FrameControl frameControl,
         ReadOnlySpan<byte> scanlineSpan,
         Span<TPixel> rowSpan,
         uint pixelOffset,
@@ -534,15 +361,15 @@ internal static class PngScanlineProcessor
         int bytesPerSample)
         where TPixel : unmanaged, IPixel<TPixel>
     {
+        uint offset = pixelOffset + frameControl.XOffset;
         TPixel pixel = default;
-        ref byte scanlineSpanRef = ref MemoryMarshal.GetReference(scanlineSpan);
         ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
 
-        if (header.BitDepth == 16)
+        if (bitDepth == 16)
         {
             Rgba64 rgba64 = default;
             int o = 0;
-            for (nuint x = pixelOffset; x < (uint)header.Width; x += increment, o += bytesPerPixel)
+            for (nuint x = offset; x < frameControl.XMax; x += increment, o += bytesPerPixel)
             {
                 rgba64.R = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o, bytesPerSample));
                 rgba64.G = BinaryPrimitives.ReadUInt16BigEndian(scanlineSpan.Slice(o + bytesPerSample, bytesPerSample));
@@ -553,11 +380,20 @@ internal static class PngScanlineProcessor
                 Unsafe.Add(ref rowSpanRef, x) = pixel;
             }
         }
+        else if (pixelOffset == 0 && increment == 1)
+        {
+            PixelOperations<TPixel>.Instance.FromRgba32Bytes(
+                configuration,
+                scanlineSpan[..(int)(frameControl.Width * bytesPerPixel)],
+                rowSpan.Slice((int)frameControl.XOffset, (int)frameControl.Width),
+                (int)frameControl.Width);
+        }
         else
         {
+            ref byte scanlineSpanRef = ref MemoryMarshal.GetReference(scanlineSpan);
             Rgba32 rgba = default;
             int o = 0;
-            for (nuint x = pixelOffset; x < (uint)header.Width; x += increment, o += bytesPerPixel)
+            for (nuint x = offset; x < frameControl.XMax; x += increment, o += bytesPerPixel)
             {
                 rgba.R = Unsafe.Add(ref scanlineSpanRef, (uint)o);
                 rgba.G = Unsafe.Add(ref scanlineSpanRef, (uint)(o + bytesPerSample));

src/ImageSharp/Formats/Png/PngThrowHelper.cs

@@ -2,6 +2,7 @@
 // Licensed under the Six Labors Split License.
 
 using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
 
 namespace SixLabors.ImageSharp.Formats.Png;
 
@@ -12,13 +13,22 @@ internal static class PngThrowHelper
         => throw new InvalidImageContentException(errorMessage, innerException);
 
     [DoesNotReturn]
-    public static void ThrowNoHeader() => throw new InvalidImageContentException("PNG Image does not contain a header chunk");
+    public static void ThrowInvalidHeader() => throw new InvalidImageContentException("PNG Image must contain a header chunk and it must be located before any other chunks.");
 
     [DoesNotReturn]
-    public static void ThrowNoData() => throw new InvalidImageContentException("PNG Image does not contain a data chunk");
+    public static void ThrowNoData() => throw new InvalidImageContentException("PNG Image does not contain a data chunk.");
 
     [DoesNotReturn]
-    public static void ThrowMissingPalette() => throw new InvalidImageContentException("PNG Image does not contain a palette chunk");
+    public static void ThrowMissingDefaultData() => throw new InvalidImageContentException("APNG Image does not contain a default data chunk.");
+
+    [DoesNotReturn]
+    public static void ThrowInvalidAnimationControl() => throw new InvalidImageContentException("APNG Image must contain a acTL chunk and it must be located before any IDAT and fdAT chunks.");
+
+    [DoesNotReturn]
+    public static void ThrowMissingFrameControl() => throw new InvalidImageContentException("One of APNG Image's frames do not have a frame control chunk.");
+
+    [DoesNotReturn]
+    public static void ThrowMissingPalette() => throw new InvalidImageContentException("PNG Image does not contain a palette chunk.");
 
     [DoesNotReturn]
     public static void ThrowInvalidChunkType() => throw new InvalidImageContentException("Invalid PNG data.");
@@ -30,7 +40,15 @@ internal static class PngThrowHelper
     public static void ThrowInvalidChunkCrc(string chunkTypeName) => throw new InvalidImageContentException($"CRC Error. PNG {chunkTypeName} chunk is corrupt!");
 
     [DoesNotReturn]
-    public static void ThrowNotSupportedColor() => throw new NotSupportedException("Unsupported PNG color type");
+    public static void ThrowInvalidParameter(object value, string message, [CallerArgumentExpression(nameof(value))] string name = "")
+        => throw new NotSupportedException($"Invalid {name}. {message}. Was '{value}'.");
+
+    [DoesNotReturn]
+    public static void ThrowInvalidParameter(object value1, object value2, string message, [CallerArgumentExpression(nameof(value1))] string name1 = "", [CallerArgumentExpression(nameof(value1))] string name2 = "")
+        => throw new NotSupportedException($"Invalid {name1} or {name2}. {message}. Was '{value1}' and '{value2}'.");
+
+    [DoesNotReturn]
+    public static void ThrowNotSupportedColor() => throw new NotSupportedException("Unsupported PNG color type.");
 
     [DoesNotReturn]
     public static void ThrowUnknownFilter() => throw new InvalidImageContentException("Unknown filter type.");

src/ImageSharp/Formats/Qoi/QoiEncoder.cs

@@ -1,8 +1,6 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
-using SixLabors.ImageSharp.Advanced;
-
 namespace SixLabors.ImageSharp.Formats.Qoi;
 
 /// <summary>
@@ -27,7 +25,7 @@ public class QoiEncoder : ImageEncoder
     /// <inheritdoc />
     protected override void Encode<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
     {
-        QoiEncoderCore encoder = new(this, image.GetMemoryAllocator(), image.GetConfiguration());
+        QoiEncoderCore encoder = new(this, image.Configuration);
         encoder.Encode(image, stream, cancellationToken);
     }
 }

src/ImageSharp/Formats/Qoi/QoiEncoderCore.cs

@@ -33,13 +33,12 @@ internal class QoiEncoderCore : IImageEncoderInternals
     /// Initializes a new instance of the <see cref="QoiEncoderCore"/> class.
     /// </summary>
     /// <param name="encoder">The encoder with options.</param>
-    /// <param name="memoryAllocator">The <see cref="MemoryAllocator" /> to use for buffer allocations.</param>
     /// <param name="configuration">The configuration of the Encoder.</param>
-    public QoiEncoderCore(QoiEncoder encoder, MemoryAllocator memoryAllocator, Configuration configuration)
+    public QoiEncoderCore(QoiEncoder encoder, Configuration configuration)
     {
         this.encoder = encoder;
-        this.memoryAllocator = memoryAllocator;
         this.configuration = configuration;
+        this.memoryAllocator = configuration.MemoryAllocator;
     }
 
     /// <inheritdoc />

src/ImageSharp/Formats/Tga/TgaEncoder.cs

@@ -1,12 +1,10 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
-using SixLabors.ImageSharp.Advanced;
-
 namespace SixLabors.ImageSharp.Formats.Tga;
 
 /// <summary>
-/// Image encoder for writing an image to a stream as a targa truevision image.
+/// Image encoder for writing an image to a stream as a Targa true-vision image.
 /// </summary>
 public sealed class TgaEncoder : ImageEncoder
 {
@@ -23,7 +21,7 @@ public sealed class TgaEncoder : ImageEncoder
     /// <inheritdoc/>
     protected override void Encode<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
     {
-        TgaEncoderCore encoder = new(this, image.GetMemoryAllocator());
+        TgaEncoderCore encoder = new(this, image.Configuration.MemoryAllocator);
         encoder.Encode(image, stream, cancellationToken);
     }
 }

src/ImageSharp/Formats/Tga/TgaEncoderCore.cs

@@ -112,7 +112,7 @@ internal sealed class TgaEncoderCore : IImageEncoderInternals
         }
         else
         {
-            this.WriteImage(image.GetConfiguration(), stream, image.Frames.RootFrame);
+            this.WriteImage(image.Configuration, stream, image.Frames.RootFrame);
         }
 
         stream.Flush();

src/ImageSharp/Formats/Tiff/Compression/Decompressors/WebpTiffCompression.cs

@@ -32,7 +32,7 @@ internal class WebpTiffCompression : TiffBaseDecompressor
     /// <inheritdoc/>
     protected override void Decompress(BufferedReadStream stream, int byteCount, int stripHeight, Span<byte> buffer, CancellationToken cancellationToken)
     {
-        using WebpDecoderCore decoder = new(this.options);
+        using WebpDecoderCore decoder = new(new WebpDecoderOptions());
         using Image<Rgb24> image = decoder.Decode<Rgb24>(stream, cancellationToken);
         CopyImageBytesToBuffer(buffer, image.Frames.RootFrame.PixelBuffer);
     }

src/ImageSharp/Formats/Tiff/Compression/TiffDecompressorsFactory.cs

@@ -4,6 +4,7 @@
 using SixLabors.ImageSharp.Formats.Tiff.Compression.Decompressors;
 using SixLabors.ImageSharp.Formats.Tiff.Constants;
 using SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation;
+using SixLabors.ImageSharp.Formats.Webp;
 using SixLabors.ImageSharp.Memory;
 
 namespace SixLabors.ImageSharp.Formats.Tiff.Compression;

src/ImageSharp/Formats/Tiff/Ifd/DirectoryReader.cs

@@ -40,7 +40,7 @@ internal class DirectoryReader
     public IList<ExifProfile> Read()
     {
         this.ByteOrder = ReadByteOrder(this.stream);
-        var headerReader = new HeaderReader(this.stream, this.ByteOrder);
+        HeaderReader headerReader = new(this.stream, this.ByteOrder);
         headerReader.ReadFileHeader();
 
         this.nextIfdOffset = headerReader.FirstIfdOffset;
@@ -52,7 +52,12 @@ internal class DirectoryReader
     private static ByteOrder ReadByteOrder(Stream stream)
     {
         Span<byte> headerBytes = stackalloc byte[2];
-        stream.Read(headerBytes);
+
+        if (stream.Read(headerBytes) != 2)
+        {
+            throw TiffThrowHelper.ThrowInvalidHeader();
+        }
+
         if (headerBytes[0] == TiffConstants.ByteOrderLittleEndian && headerBytes[1] == TiffConstants.ByteOrderLittleEndian)
         {
             return ByteOrder.LittleEndian;
@@ -68,10 +73,10 @@ internal class DirectoryReader
 
     private IList<ExifProfile> ReadIfds(bool isBigTiff)
     {
-        var readers = new List<EntryReader>();
+        List<EntryReader> readers = new();
         while (this.nextIfdOffset != 0 && this.nextIfdOffset < (ulong)this.stream.Length)
         {
-            var reader = new EntryReader(this.stream, this.ByteOrder, this.allocator);
+            EntryReader reader = new(this.stream, this.ByteOrder, this.allocator);
             reader.ReadTags(isBigTiff, this.nextIfdOffset);
 
             if (reader.BigValues.Count > 0)
@@ -85,6 +90,11 @@ internal class DirectoryReader
                 }
             }
 
+            if (this.nextIfdOffset >= reader.NextIfdOffset && reader.NextIfdOffset != 0)
+            {
+                TiffThrowHelper.ThrowImageFormatException("TIFF image contains circular directory offsets");
+            }
+
             this.nextIfdOffset = reader.NextIfdOffset;
             readers.Add(reader);
 
@@ -94,11 +104,11 @@ internal class DirectoryReader
             }
         }
 
-        var list = new List<ExifProfile>(readers.Count);
+        List<ExifProfile> list = new(readers.Count);
         foreach (EntryReader reader in readers)
         {
             reader.ReadBigValues();
-            var profile = new ExifProfile(reader.Values, reader.InvalidTags);
+            ExifProfile profile = new(reader.Values, reader.InvalidTags);
             list.Add(profile);
         }
 

src/ImageSharp/Formats/Tiff/TiffEncoder.cs

@@ -1,7 +1,6 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
-using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Compression.Zlib;
 using SixLabors.ImageSharp.Formats.Tiff.Constants;
 using SixLabors.ImageSharp.Processing;
@@ -48,7 +47,7 @@ public class TiffEncoder : QuantizingImageEncoder
     /// <inheritdoc/>
     protected override void Encode<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
     {
-        TiffEncoderCore encode = new(this, image.GetMemoryAllocator());
+        TiffEncoderCore encode = new(this, image.Configuration.MemoryAllocator);
         encode.Encode(image, stream, cancellationToken);
     }
 }

src/ImageSharp/Formats/Tiff/TiffEncoderCore.cs

@@ -128,7 +128,7 @@ internal sealed class TiffEncoderCore : IImageEncoderInternals
         Guard.NotNull(image, nameof(image));
         Guard.NotNull(stream, nameof(stream));
 
-        this.configuration = image.GetConfiguration();
+        this.configuration = image.Configuration;
 
         ImageFrameMetadata rootFrameMetaData = image.Frames.RootFrame.Metadata;
         TiffFrameMetadata rootFrameTiffMetaData = rootFrameMetaData.GetTiffMetadata();

src/ImageSharp/Formats/Webp/BackgroundColorHandling.cs

@@ -0,0 +1,21 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Formats.Webp;
+
+/// <summary>
+/// Enum to decide how to handle the background color of the Animation chunk during decoding.
+/// </summary>
+public enum BackgroundColorHandling
+{
+    /// <summary>
+    /// The background color of the ANIM chunk will be used to initialize the canvas to fill the unused space on the canvas around the frame.
+    /// Also, if AnimationDisposalMethod.Dispose is used, this color will be used to restore the canvas background.
+    /// </summary>
+    Standard = 0,
+
+    /// <summary>
+    /// The background color of the ANIM chunk is ignored and instead the canvas is initialized with transparent, BGRA(0, 0, 0, 0).
+    /// </summary>
+    Ignore = 1
+}

src/ImageSharp/Formats/Webp/Lossless/Vp8LEncoder.cs

@@ -502,7 +502,7 @@ internal class Vp8LEncoder : IDisposable
             doNotCache = true;
 
             // Go brute force on all transforms.
-            foreach (EntropyIx entropyIx in Enum.GetValues(typeof(EntropyIx)).Cast<EntropyIx>())
+            foreach (EntropyIx entropyIx in Enum.GetValues<EntropyIx>())
             {
                 // We can only apply kPalette or kPaletteAndSpatial if we can indeed use a palette.
                 if ((entropyIx != EntropyIx.Palette && entropyIx != EntropyIx.PaletteAndSpatial) || usePalette)

src/ImageSharp/Formats/Webp/WebpAnimationDecoder.cs

@@ -52,17 +52,24 @@ internal class WebpAnimationDecoder : IDisposable
     /// </summary>
     private IMemoryOwner<byte>? alphaData;
 
+    /// <summary>
+    /// The flag to decide how to handle the background color in the Animation Chunk.
+    /// </summary>
+    private readonly BackgroundColorHandling backgroundColorHandling;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="WebpAnimationDecoder"/> class.
     /// </summary>
     /// <param name="memoryAllocator">The memory allocator.</param>
     /// <param name="configuration">The global configuration.</param>
     /// <param name="maxFrames">The maximum number of frames to decode. Inclusive.</param>
-    public WebpAnimationDecoder(MemoryAllocator memoryAllocator, Configuration configuration, uint maxFrames)
+    /// <param name="backgroundColorHandling">The flag to decide how to handle the background color in the Animation Chunk.</param>
+    public WebpAnimationDecoder(MemoryAllocator memoryAllocator, Configuration configuration, uint maxFrames, BackgroundColorHandling backgroundColorHandling)
     {
         this.memoryAllocator = memoryAllocator;
         this.configuration = configuration;
         this.maxFrames = maxFrames;
+        this.backgroundColorHandling = backgroundColorHandling;
     }
 
     /// <summary>
@@ -94,7 +101,10 @@ internal class WebpAnimationDecoder : IDisposable
             switch (chunkType)
             {
                 case WebpChunkType.Animation:
-                    uint dataSize = this.ReadFrame(stream, ref image, ref previousFrame, width, height, features.AnimationBackgroundColor!.Value);
+                    Color backgroundColor = this.backgroundColorHandling == BackgroundColorHandling.Ignore
+                        ? new Color(new Bgra32(0, 0, 0, 0))
+                        : features.AnimationBackgroundColor!.Value;
+                    uint dataSize = this.ReadFrame(stream, ref image, ref previousFrame, width, height, backgroundColor);
                     remainingBytes -= (int)dataSize;
                     break;
                 case WebpChunkType.Xmp:

src/ImageSharp/Formats/Webp/WebpDecoder.cs

@@ -8,7 +8,7 @@ namespace SixLabors.ImageSharp.Formats.Webp;
 /// <summary>
 /// Image decoder for generating an image out of a webp stream.
 /// </summary>
-public sealed class WebpDecoder : ImageDecoder
+public sealed class WebpDecoder : SpecializedImageDecoder<WebpDecoderOptions>
 {
     private WebpDecoder()
     {
@@ -25,25 +25,33 @@ public sealed class WebpDecoder : ImageDecoder
         Guard.NotNull(options, nameof(options));
         Guard.NotNull(stream, nameof(stream));
 
-        using WebpDecoderCore decoder = new(options);
+        using WebpDecoderCore decoder = new(new WebpDecoderOptions() { GeneralOptions = options });
         return decoder.Identify(options.Configuration, stream, cancellationToken);
     }
 
     /// <inheritdoc/>
-    protected override Image<TPixel> Decode<TPixel>(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
+    protected override Image<TPixel> Decode<TPixel>(WebpDecoderOptions options, Stream stream, CancellationToken cancellationToken)
     {
         Guard.NotNull(options, nameof(options));
         Guard.NotNull(stream, nameof(stream));
 
         using WebpDecoderCore decoder = new(options);
-        Image<TPixel> image = decoder.Decode<TPixel>(options.Configuration, stream, cancellationToken);
+        Image<TPixel> image = decoder.Decode<TPixel>(options.GeneralOptions.Configuration, stream, cancellationToken);
 
-        ScaleToTargetSize(options, image);
+        ScaleToTargetSize(options.GeneralOptions, image);
 
         return image;
     }
 
+    /// <inheritdoc/>
+    protected override Image Decode(WebpDecoderOptions options, Stream stream, CancellationToken cancellationToken)
+        => this.Decode<Rgba32>(options, stream, cancellationToken);
+
     /// <inheritdoc/>
     protected override Image Decode(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
         => this.Decode<Rgba32>(options, stream, cancellationToken);
+
+    /// <inheritdoc/>
+    protected override WebpDecoderOptions CreateDefaultSpecializedOptions(DecoderOptions options)
+        => new() { GeneralOptions = options };
 }

src/ImageSharp/Formats/Webp/WebpDecoderCore.cs

@@ -48,16 +48,22 @@ internal sealed class WebpDecoderCore : IImageDecoderInternals, IDisposable
     /// </summary>
     private WebpImageInfo? webImageInfo;
 
+    /// <summary>
+    /// The flag to decide how to handle the background color in the Animation Chunk.
+    /// </summary>
+    private BackgroundColorHandling backgroundColorHandling;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="WebpDecoderCore"/> class.
     /// </summary>
     /// <param name="options">The decoder options.</param>
-    public WebpDecoderCore(DecoderOptions options)
+    public WebpDecoderCore(WebpDecoderOptions options)
     {
-        this.Options = options;
+        this.Options = options.GeneralOptions;
-        this.configuration = options.Configuration;
+        this.backgroundColorHandling = options.BackgroundColorHandling;
-        this.skipMetadata = options.SkipMetadata;
+        this.configuration = options.GeneralOptions.Configuration;
-        this.maxFrames = options.MaxFrames;
+        this.skipMetadata = options.GeneralOptions.SkipMetadata;
+        this.maxFrames = options.GeneralOptions.MaxFrames;
         this.memoryAllocator = this.configuration.MemoryAllocator;
     }
 
@@ -83,7 +89,7 @@ internal sealed class WebpDecoderCore : IImageDecoderInternals, IDisposable
             {
                 if (this.webImageInfo.Features is { Animation: true })
                 {
-                    using WebpAnimationDecoder animationDecoder = new(this.memoryAllocator, this.configuration, this.maxFrames);
+                    using WebpAnimationDecoder animationDecoder = new(this.memoryAllocator, this.configuration, this.maxFrames, this.backgroundColorHandling);
                     return animationDecoder.Decode<TPixel>(stream, this.webImageInfo.Features, this.webImageInfo.Width, this.webImageInfo.Height, fileSize);
                 }
 

src/ImageSharp/Formats/Webp/WebpDecoderOptions.cs

@@ -0,0 +1,21 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Formats.Webp;
+
+/// <summary>
+/// Configuration options for decoding webp images.
+/// </summary>
+public sealed class WebpDecoderOptions : ISpecializedDecoderOptions
+{
+    /// <inheritdoc/>
+    public DecoderOptions GeneralOptions { get; init; } = new();
+
+    /// <summary>
+    /// Gets the flag to decide how to handle the background color Animation Chunk.
+    /// The specification is vague on how to handle the background color of the animation chunk.
+    /// This option let's the user choose how to deal with it.
+    /// </summary>
+    /// <see href="https://developers.google.com/speed/webp/docs/riff_container#animation"/>
+    public BackgroundColorHandling BackgroundColorHandling { get; init; } = BackgroundColorHandling.Standard;
+}

src/ImageSharp/Formats/Webp/WebpEncoder.cs

@@ -82,7 +82,7 @@ public sealed class WebpEncoder : ImageEncoder
     /// <inheritdoc/>
     protected override void Encode<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
     {
-        WebpEncoderCore encoder = new(this, image.GetConfiguration());
+        WebpEncoderCore encoder = new(this, image.Configuration);
         encoder.Encode(image, stream, cancellationToken);
     }
 }

src/ImageSharp/IO/BufferedReadStream.cs

@@ -68,6 +68,11 @@ internal sealed class BufferedReadStream : Stream
         this.readBufferIndex = int.MinValue;
     }
 
+    /// <summary>
+    /// Gets the number indicating the EOF hits occured while reading from this instance.
+    /// </summary>
+    public int EofHitCount { get; private set; }
+
     /// <summary>
     /// Gets the size, in bytes, of the underlying buffer.
     /// </summary>
@@ -142,6 +147,7 @@ internal sealed class BufferedReadStream : Stream
     {
         if (this.readerPosition >= this.Length)
         {
+            this.EofHitCount++;
             return -1;
         }
 
@@ -294,7 +300,7 @@ internal sealed class BufferedReadStream : Stream
 
         this.readerPosition += n;
         this.readBufferIndex += n;
-
+        this.CheckEof(n);
         return n;
     }
 
@@ -352,6 +358,7 @@ internal sealed class BufferedReadStream : Stream
 
         this.Position += n;
 
+        this.CheckEof(n);
         return n;
     }
 
@@ -418,4 +425,13 @@ internal sealed class BufferedReadStream : Stream
             Buffer.BlockCopy(this.readBuffer, this.readBufferIndex, buffer, offset, count);
         }
     }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private void CheckEof(int read)
+    {
+        if (read == 0)
+        {
+            this.EofHitCount++;
+        }
+    }
 }

src/ImageSharp/Image.cs

@@ -17,7 +17,6 @@ namespace SixLabors.ImageSharp;
 public abstract partial class Image : IDisposable, IConfigurationProvider
 {
     private bool isDisposed;
-    private readonly Configuration configuration;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="Image"/> class.
@@ -26,12 +25,12 @@ public abstract partial class Image : IDisposable, IConfigurationProvider
     /// <param name="pixelType">The pixel type information.</param>
     /// <param name="metadata">The image metadata.</param>
     /// <param name="size">The size in px units.</param>
-    protected Image(Configuration configuration, PixelTypeInfo pixelType, ImageMetadata? metadata, Size size)
+    protected Image(Configuration configuration, PixelTypeInfo pixelType, ImageMetadata metadata, Size size)
     {
-        this.configuration = configuration;
+        this.Configuration = configuration;
         this.PixelType = pixelType;
         this.Size = size;
-        this.Metadata = metadata ?? new ImageMetadata();
+        this.Metadata = metadata;
     }
 
     /// <summary>
@@ -45,7 +44,7 @@ public abstract partial class Image : IDisposable, IConfigurationProvider
     internal Image(
         Configuration configuration,
         PixelTypeInfo pixelType,
-        ImageMetadata? metadata,
+        ImageMetadata metadata,
         int width,
         int height)
         : this(configuration, pixelType, metadata, new Size(width, height))
@@ -53,7 +52,7 @@ public abstract partial class Image : IDisposable, IConfigurationProvider
     }
 
     /// <inheritdoc/>
-    Configuration IConfigurationProvider.Configuration => this.configuration;
+    public Configuration Configuration { get; }
 
     /// <summary>
     /// Gets information about the image pixels.
@@ -147,7 +146,7 @@ public abstract partial class Image : IDisposable, IConfigurationProvider
     /// <typeparam name="TPixel2">The pixel format.</typeparam>
     /// <returns>The <see cref="Image{TPixel2}"/></returns>
     public Image<TPixel2> CloneAs<TPixel2>()
-        where TPixel2 : unmanaged, IPixel<TPixel2> => this.CloneAs<TPixel2>(this.GetConfiguration());
+        where TPixel2 : unmanaged, IPixel<TPixel2> => this.CloneAs<TPixel2>(this.Configuration);
 
     /// <summary>
     /// Returns a copy of the image in the given pixel format.

src/ImageSharp/ImageExtensions.cs

@@ -47,7 +47,7 @@ public static partial class ImageExtensions
     {
         Guard.NotNull(path, nameof(path));
         Guard.NotNull(encoder, nameof(encoder));
-        using Stream fs = source.GetConfiguration().FileSystem.Create(path);
+        using Stream fs = source.Configuration.FileSystem.Create(path);
         source.Save(fs, encoder);
     }
 
@@ -70,7 +70,7 @@ public static partial class ImageExtensions
         Guard.NotNull(path, nameof(path));
         Guard.NotNull(encoder, nameof(encoder));
 
-        await using Stream fs = source.GetConfiguration().FileSystem.CreateAsynchronous(path);
+        await using Stream fs = source.Configuration.FileSystem.CreateAsynchronous(path);
         await source.SaveAsync(fs, encoder, cancellationToken).ConfigureAwait(false);
     }
 
@@ -94,14 +94,14 @@ public static partial class ImageExtensions
             throw new NotSupportedException("Cannot write to the stream.");
         }
 
-        IImageEncoder encoder = source.GetConfiguration().ImageFormatsManager.GetEncoder(format);
+        IImageEncoder encoder = source.Configuration.ImageFormatsManager.GetEncoder(format);
 
         if (encoder is null)
         {
             StringBuilder sb = new();
             sb.AppendLine("No encoder was found for the provided mime type. Registered encoders include:");
 
-            foreach (KeyValuePair<IImageFormat, IImageEncoder> val in source.GetConfiguration().ImageFormatsManager.ImageEncoders)
+            foreach (KeyValuePair<IImageFormat, IImageEncoder> val in source.Configuration.ImageFormatsManager.ImageEncoders)
             {
                 sb.AppendFormat(CultureInfo.InvariantCulture, " - {0} : {1}{2}", val.Key.Name, val.Value.GetType().Name, Environment.NewLine);
             }
@@ -138,14 +138,14 @@ public static partial class ImageExtensions
             throw new NotSupportedException("Cannot write to the stream.");
         }
 
-        IImageEncoder encoder = source.GetConfiguration().ImageFormatsManager.GetEncoder(format);
+        IImageEncoder encoder = source.Configuration.ImageFormatsManager.GetEncoder(format);
 
         if (encoder is null)
         {
             StringBuilder sb = new();
             sb.AppendLine("No encoder was found for the provided mime type. Registered encoders include:");
 
-            foreach (KeyValuePair<IImageFormat, IImageEncoder> val in source.GetConfiguration().ImageFormatsManager.ImageEncoders)
+            foreach (KeyValuePair<IImageFormat, IImageEncoder> val in source.Configuration.ImageFormatsManager.ImageEncoders)
             {
                 sb.AppendFormat(CultureInfo.InvariantCulture, " - {0} : {1}{2}", val.Key.Name, val.Value.GetType().Name, Environment.NewLine);
             }

src/ImageSharp/ImageFrame.cs

@@ -15,8 +15,6 @@ namespace SixLabors.ImageSharp;
 /// </summary>
 public abstract partial class ImageFrame : IConfigurationProvider, IDisposable
 {
-    private readonly Configuration configuration;
-
     /// <summary>
     /// Initializes a new instance of the <see cref="ImageFrame"/> class.
     /// </summary>
@@ -26,10 +24,7 @@ public abstract partial class ImageFrame : IConfigurationProvider, IDisposable
     /// <param name="metadata">The <see cref="ImageFrameMetadata"/>.</param>
     protected ImageFrame(Configuration configuration, int width, int height, ImageFrameMetadata metadata)
     {
-        Guard.NotNull(configuration, nameof(configuration));
+        this.Configuration = configuration;
-        Guard.NotNull(metadata, nameof(metadata));
-
-        this.configuration = configuration ?? Configuration.Default;
         this.Width = width;
         this.Height = height;
         this.Metadata = metadata;
@@ -51,19 +46,19 @@ public abstract partial class ImageFrame : IConfigurationProvider, IDisposable
     public ImageFrameMetadata Metadata { get; }
 
     /// <inheritdoc/>
-    Configuration IConfigurationProvider.Configuration => this.configuration;
+    public Configuration Configuration { get; }
 
     /// <summary>
     /// Gets the size of the frame.
     /// </summary>
     /// <returns>The <see cref="Size"/></returns>
-    public Size Size() => new Size(this.Width, this.Height);
+    public Size Size() => new(this.Width, this.Height);
 
     /// <summary>
     /// Gets the bounds of the frame.
     /// </summary>
     /// <returns>The <see cref="Rectangle"/></returns>
-    public Rectangle Bounds() => new Rectangle(0, 0, this.Width, this.Height);
+    public Rectangle Bounds() => new(0, 0, this.Width, this.Height);
 
     /// <inheritdoc />
     public void Dispose()
@@ -84,6 +79,7 @@ public abstract partial class ImageFrame : IConfigurationProvider, IDisposable
     /// <summary>
     /// Updates the size of the image frame.
     /// </summary>
+    /// <param name="size">The size.</param>
     internal void UpdateSize(Size size)
     {
         this.Width = size.Width;

src/ImageSharp/ImageFrameCollection{TPixel}.cs

@@ -2,7 +2,6 @@
 // Licensed under the Six Labors Split License.
 
 using System.Collections;
-using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -24,7 +23,7 @@ public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumer
         this.parent = parent ?? throw new ArgumentNullException(nameof(parent));
 
         // Frames are already cloned within the caller
-        this.frames.Add(new ImageFrame<TPixel>(parent.GetConfiguration(), width, height, backgroundColor));
+        this.frames.Add(new ImageFrame<TPixel>(parent.Configuration, width, height, backgroundColor));
     }
 
     internal ImageFrameCollection(Image<TPixel> parent, int width, int height, MemoryGroup<TPixel> memorySource)
@@ -32,7 +31,7 @@ public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumer
         this.parent = parent ?? throw new ArgumentNullException(nameof(parent));
 
         // Frames are already cloned within the caller
-        this.frames.Add(new ImageFrame<TPixel>(parent.GetConfiguration(), width, height, memorySource));
+        this.frames.Add(new ImageFrame<TPixel>(parent.Configuration, width, height, memorySource));
     }
 
     internal ImageFrameCollection(Image<TPixel> parent, IEnumerable<ImageFrame<TPixel>> frames)
@@ -138,7 +137,7 @@ public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumer
         this.EnsureNotDisposed();
 
         this.ValidateFrame(source);
-        ImageFrame<TPixel> clonedFrame = source.Clone(this.parent.GetConfiguration());
+        ImageFrame<TPixel> clonedFrame = source.Clone(this.parent.Configuration);
         this.frames.Insert(index, clonedFrame);
         return clonedFrame;
     }
@@ -153,7 +152,7 @@ public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumer
         this.EnsureNotDisposed();
 
         this.ValidateFrame(source);
-        ImageFrame<TPixel> clonedFrame = source.Clone(this.parent.GetConfiguration());
+        ImageFrame<TPixel> clonedFrame = source.Clone(this.parent.Configuration);
         this.frames.Add(clonedFrame);
         return clonedFrame;
     }
@@ -169,7 +168,7 @@ public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumer
         this.EnsureNotDisposed();
 
         ImageFrame<TPixel> frame = ImageFrame.LoadPixelData(
-            this.parent.GetConfiguration(),
+            this.parent.Configuration,
             source,
             this.RootFrame.Width,
             this.RootFrame.Height);
@@ -270,7 +269,7 @@ public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumer
 
         this.frames.Remove(frame);
 
-        return new Image<TPixel>(this.parent.GetConfiguration(), this.parent.Metadata.DeepClone(), new[] { frame });
+        return new Image<TPixel>(this.parent.Configuration, this.parent.Metadata.DeepClone(), new[] { frame });
     }
 
     /// <summary>
@@ -285,7 +284,7 @@ public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumer
 
         ImageFrame<TPixel> frame = this[index];
         ImageFrame<TPixel> clonedFrame = frame.Clone();
-        return new Image<TPixel>(this.parent.GetConfiguration(), this.parent.Metadata.DeepClone(), new[] { clonedFrame });
+        return new Image<TPixel>(this.parent.Configuration, this.parent.Metadata.DeepClone(), new[] { clonedFrame });
     }
 
     /// <summary>
@@ -299,7 +298,7 @@ public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumer
         this.EnsureNotDisposed();
 
         ImageFrame<TPixel> frame = new(
-            this.parent.GetConfiguration(),
+            this.parent.Configuration,
             this.RootFrame.Width,
             this.RootFrame.Height);
         this.frames.Add(frame);
@@ -365,7 +364,7 @@ public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumer
     public ImageFrame<TPixel> CreateFrame(TPixel backgroundColor)
     {
         ImageFrame<TPixel> frame = new(
-            this.parent.GetConfiguration(),
+            this.parent.Configuration,
             this.RootFrame.Width,
             this.RootFrame.Height,
             backgroundColor);
@@ -414,7 +413,7 @@ public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumer
     private ImageFrame<TPixel> CopyNonCompatibleFrame(ImageFrame source)
     {
         ImageFrame<TPixel> result = new(
-            this.parent.GetConfiguration(),
+            this.parent.Configuration,
             source.Size(),
             source.Metadata.DeepClone());
         source.CopyPixelsTo(result.PixelBuffer.FastMemoryGroup);

src/ImageSharp/ImageFrame{TPixel}.cs

@@ -66,7 +66,7 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
         Guard.MustBeGreaterThan(width, 0, nameof(width));
         Guard.MustBeGreaterThan(height, 0, nameof(height));
 
-        this.PixelBuffer = this.GetConfiguration().MemoryAllocator.Allocate2D<TPixel>(
+        this.PixelBuffer = this.Configuration.MemoryAllocator.Allocate2D<TPixel>(
             width,
             height,
             configuration.PreferContiguousImageBuffers,
@@ -99,7 +99,7 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
         Guard.MustBeGreaterThan(width, 0, nameof(width));
         Guard.MustBeGreaterThan(height, 0, nameof(height));
 
-        this.PixelBuffer = this.GetConfiguration().MemoryAllocator.Allocate2D<TPixel>(
+        this.PixelBuffer = this.Configuration.MemoryAllocator.Allocate2D<TPixel>(
             width,
             height,
             configuration.PreferContiguousImageBuffers);
@@ -146,7 +146,7 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
         Guard.NotNull(configuration, nameof(configuration));
         Guard.NotNull(source, nameof(source));
 
-        this.PixelBuffer = this.GetConfiguration().MemoryAllocator.Allocate2D<TPixel>(
+        this.PixelBuffer = this.Configuration.MemoryAllocator.Allocate2D<TPixel>(
             source.PixelBuffer.Width,
             source.PixelBuffer.Height,
             configuration.PreferContiguousImageBuffers);
@@ -371,7 +371,7 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
         }
 
         this.PixelBuffer.FastMemoryGroup.TransformTo(destination, (s, d)
-            => PixelOperations<TPixel>.Instance.To(this.GetConfiguration(), s, d));
+            => PixelOperations<TPixel>.Instance.To(this.Configuration, s, d));
     }
 
     /// <inheritdoc/>
@@ -381,7 +381,7 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
     /// Clones the current instance.
     /// </summary>
     /// <returns>The <see cref="ImageFrame{TPixel}"/></returns>
-    internal ImageFrame<TPixel> Clone() => this.Clone(this.GetConfiguration());
+    internal ImageFrame<TPixel> Clone() => this.Clone(this.Configuration);
 
     /// <summary>
     /// Clones the current instance.
@@ -396,7 +396,7 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
     /// <typeparam name="TPixel2">The pixel format.</typeparam>
     /// <returns>The <see cref="ImageFrame{TPixel2}"/></returns>
     internal ImageFrame<TPixel2>? CloneAs<TPixel2>()
-        where TPixel2 : unmanaged, IPixel<TPixel2> => this.CloneAs<TPixel2>(this.GetConfiguration());
+        where TPixel2 : unmanaged, IPixel<TPixel2> => this.CloneAs<TPixel2>(this.Configuration);
 
     /// <summary>
     /// Returns a copy of the image frame in the given pixel format.

src/ImageSharp/ImageSharp.csproj

@@ -22,8 +22,8 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <!--Bump to V3 prior to tagged release.-->
+    <!--Bump to v3.1 prior to tagged release.-->
-    <MinVerMinimumMajorMinor>3.0</MinVerMinimumMajorMinor>
+    <MinVerMinimumMajorMinor>3.1</MinVerMinimumMajorMinor>
   </PropertyGroup>
 
   <Choose>

src/ImageSharp/Image{TPixel}.cs

@@ -78,12 +78,12 @@ public sealed class Image<TPixel> : Image
     /// <param name="height">The height of the image in pixels.</param>
     /// <param name="metadata">The images metadata.</param>
     internal Image(Configuration configuration, int width, int height, ImageMetadata? metadata)
-        : base(configuration, PixelTypeInfo.Create<TPixel>(), metadata, width, height)
+        : base(configuration, PixelTypeInfo.Create<TPixel>(), metadata ?? new(), width, height)
         => this.frames = new ImageFrameCollection<TPixel>(this, width, height, default(TPixel));
 
     /// <summary>
     /// Initializes a new instance of the <see cref="Image{TPixel}"/> class
-    /// wrapping an external <see cref="Buffer2D{TPixel}"/> pixel bufferx.
+    /// wrapping an external <see cref="Buffer2D{TPixel}"/> pixel buffer.
     /// </summary>
     /// <param name="configuration">The configuration providing initialization code which allows extending the library.</param>
     /// <param name="pixelBuffer">Pixel buffer.</param>
@@ -129,7 +129,7 @@ public sealed class Image<TPixel> : Image
         int height,
         TPixel backgroundColor,
         ImageMetadata? metadata)
-        : base(configuration, PixelTypeInfo.Create<TPixel>(), metadata, width, height)
+        : base(configuration, PixelTypeInfo.Create<TPixel>(), metadata ?? new(), width, height)
         => this.frames = new ImageFrameCollection<TPixel>(this, width, height, backgroundColor);
 
     /// <summary>
@@ -328,7 +328,7 @@ public sealed class Image<TPixel> : Image
     /// Clones the current image
     /// </summary>
     /// <returns>Returns a new image with all the same metadata as the original.</returns>
-    public Image<TPixel> Clone() => this.Clone(this.GetConfiguration());
+    public Image<TPixel> Clone() => this.Clone(this.Configuration);
 
     /// <summary>
     /// Clones the current image with the given configuration.

src/ImageSharp/Memory/Allocators/UniformUnmanagedMemoryPoolMemoryAllocator.cs

@@ -117,6 +117,11 @@ internal sealed class UniformUnmanagedMemoryPoolMemoryAllocator : MemoryAllocato
         AllocationOptions options = AllocationOptions.None)
     {
         long totalLengthInBytes = totalLength * Unsafe.SizeOf<T>();
+        if (totalLengthInBytes < 0)
+        {
+            throw new InvalidMemoryOperationException("Attempted to allocate a MemoryGroup of a size that is not representable.");
+        }
+
         if (totalLengthInBytes <= this.sharedArrayPoolThresholdInBytes)
         {
             var buffer = new SharedArrayPoolBuffer<T>((int)totalLength);

src/ImageSharp/Memory/Buffer2D{T}.cs

@@ -9,9 +9,6 @@ namespace SixLabors.ImageSharp.Memory;
 /// Represents a buffer of value type objects
 /// interpreted as a 2D region of <see cref="Width"/> x <see cref="Height"/> elements.
 /// </summary>
-/// <remarks>
-/// Before RC1, this class might be target of API changes, use it on your own risk!
-/// </remarks>
 /// <typeparam name="T">The value type.</typeparam>
 public sealed class Buffer2D<T> : IDisposable
     where T : struct

src/ImageSharp/Metadata/Profiles/Exif/Tags/ExifTag.LongArray.cs

@@ -56,11 +56,6 @@ public abstract partial class ExifTag
     /// </summary>
     public static ExifTag<uint[]> IntergraphRegisters { get; } = new ExifTag<uint[]>(ExifTagValue.IntergraphRegisters);
 
-    /// <summary>
-    /// Gets the TimeZoneOffset exif tag.
-    /// </summary>
-    public static ExifTag<uint[]> TimeZoneOffset { get; } = new ExifTag<uint[]>(ExifTagValue.TimeZoneOffset);
-
     /// <summary>
     /// Gets the offset to child IFDs exif tag.
     /// </summary>

src/ImageSharp/Metadata/Profiles/Exif/Tags/ExifTag.Rational.cs

@@ -165,4 +165,9 @@ public abstract partial class ExifTag
     /// Gets the GPSDestDistance exif tag.
     /// </summary>
     public static ExifTag<Rational> GPSDestDistance { get; } = new ExifTag<Rational>(ExifTagValue.GPSDestDistance);
+
+    /// <summary>
+    /// Gets the GPSHPositioningError exif tag.
+    /// </summary>
+    public static ExifTag<Rational> GPSHPositioningError { get; } = new ExifTag<Rational>(ExifTagValue.GPSHPositioningError);
 }

src/ImageSharp/Metadata/Profiles/Exif/Tags/ExifTag.SignedShortArray.cs

@@ -0,0 +1,13 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Metadata.Profiles.Exif;
+
+/// <content/>
+public abstract partial class ExifTag
+{
+    /// <summary>
+    /// Gets the TimeZoneOffset exif tag.
+    /// </summary>
+    public static ExifTag<short[]> TimeZoneOffset { get; } = new ExifTag<short[]>(ExifTagValue.TimeZoneOffset);
+}

src/ImageSharp/Metadata/Profiles/Exif/Tags/ExifTagValue.cs

@@ -1691,6 +1691,11 @@ internal enum ExifTagValue
     /// </summary>
     GPSDifferential = 0x001E,
 
+    /// <summary>
+    /// GPSHPositioningError
+    /// </summary>
+    GPSHPositioningError = 0x001F,
+
     /// <summary>
     /// Used in the Oce scanning process.
     /// Identifies the scanticket used in the scanning process.

src/ImageSharp/Metadata/Profiles/Exif/Values/ExifSignedShortArray.cs

@@ -5,6 +5,11 @@ namespace SixLabors.ImageSharp.Metadata.Profiles.Exif;
 
 internal sealed class ExifSignedShortArray : ExifArrayValue<short>
 {
+    public ExifSignedShortArray(ExifTag<short[]> tag)
+        : base(tag)
+    {
+    }
+
     public ExifSignedShortArray(ExifTagValue tag)
         : base(tag)
     {

src/ImageSharp/Metadata/Profiles/Exif/Values/ExifValues.cs

@@ -144,8 +144,6 @@ internal static partial class ExifValues
                 return new ExifLongArray(ExifTag.StripRowCounts);
             case ExifTagValue.IntergraphRegisters:
                 return new ExifLongArray(ExifTag.IntergraphRegisters);
-            case ExifTagValue.TimeZoneOffset:
-                return new ExifLongArray(ExifTag.TimeZoneOffset);
             case ExifTagValue.SubIFDs:
                 return new ExifLongArray(ExifTag.SubIFDs);
 
@@ -243,6 +241,8 @@ internal static partial class ExifValues
                 return new ExifRational(ExifTag.GPSDestBearing);
             case ExifTagValue.GPSDestDistance:
                 return new ExifRational(ExifTag.GPSDestDistance);
+            case ExifTagValue.GPSHPositioningError:
+                return new ExifRational(ExifTag.GPSHPositioningError);
 
             case ExifTagValue.WhitePoint:
                 return new ExifRationalArray(ExifTag.WhitePoint);
@@ -417,6 +417,9 @@ internal static partial class ExifValues
             case ExifTagValue.Decode:
                 return new ExifSignedRationalArray(ExifTag.Decode);
 
+            case ExifTagValue.TimeZoneOffset:
+                return new ExifSignedShortArray(ExifTag.TimeZoneOffset);
+
             case ExifTagValue.ImageDescription:
                 return new ExifString(ExifTag.ImageDescription);
             case ExifTagValue.Make:

src/ImageSharp/Metadata/Profiles/ICC/IccReader.cs

@@ -87,15 +87,21 @@ internal sealed class IccReader
         foreach (IccTagTableEntry tag in tagTable)
         {
             IccTagDataEntry entry;
-
+            if (store.TryGetValue(tag.Offset, out IccTagDataEntry? value))
-            try
             {
-                entry = reader.ReadTagDataEntry(tag);
+                entry = value;
             }
-            catch
+            else
             {
-                // Ignore tags that could not be read
+                try
-                continue;
+                {
+                    entry = reader.ReadTagDataEntry(tag);
+                }
+                catch
+                {
+                    // Ignore tags that could not be read
+                    continue;
+                }
             }
 
             entry.TagSignature = tag.Signature;

src/ImageSharp/Primitives/Rational.cs

@@ -70,7 +70,7 @@ public readonly struct Rational : IEquatable<Rational>
     /// <param name="bestPrecision">Whether to use the best possible precision when parsing the value.</param>
     public Rational(double value, bool bestPrecision)
     {
-        var rational = LongRational.FromDouble(Math.Abs(value), bestPrecision);
+        LongRational rational = LongRational.FromDouble(Math.Abs(value), bestPrecision);
 
         this.Numerator = (uint)rational.Numerator;
         this.Denominator = (uint)rational.Denominator;
@@ -109,7 +109,7 @@ public readonly struct Rational : IEquatable<Rational>
     /// <returns>
     /// The <see cref="Rational"/>.
     /// </returns>
-    public static Rational FromDouble(double value) => new Rational(value, false);
+    public static Rational FromDouble(double value) => new(value, false);
 
     /// <summary>
     /// Converts the specified <see cref="double"/> to an instance of this type.
@@ -119,24 +119,19 @@ public readonly struct Rational : IEquatable<Rational>
     /// <returns>
     /// The <see cref="Rational"/>.
     /// </returns>
-    public static Rational FromDouble(double value, bool bestPrecision) => new Rational(value, bestPrecision);
+    public static Rational FromDouble(double value, bool bestPrecision) => new(value, bestPrecision);
 
     /// <inheritdoc/>
     public override bool Equals(object? obj) => obj is Rational other && this.Equals(other);
 
     /// <inheritdoc/>
     public bool Equals(Rational other)
-    {
+        => this.Numerator == other.Numerator && this.Denominator == other.Denominator;
-        var left = new LongRational(this.Numerator, this.Denominator);
-        var right = new LongRational(other.Numerator, other.Denominator);
-
-        return left.Equals(right);
-    }
 
     /// <inheritdoc/>
     public override int GetHashCode()
     {
-        var self = new LongRational(this.Numerator, this.Denominator);
+        LongRational self = new(this.Numerator, this.Denominator);
         return self.GetHashCode();
     }
 
@@ -169,7 +164,7 @@ public readonly struct Rational : IEquatable<Rational>
     /// <returns>The <see cref="string"/></returns>
     public string ToString(IFormatProvider provider)
     {
-        var rational = new LongRational(this.Numerator, this.Denominator);
+        LongRational rational = new(this.Numerator, this.Denominator);
         return rational.ToString(provider);
     }
 }

src/ImageSharp/Processing/Extensions/ProcessingExtensions.IntegralImage.cs

@@ -54,7 +54,7 @@ public static partial class ProcessingExtensions
     public static Buffer2D<ulong> CalculateIntegralImage<TPixel>(this ImageFrame<TPixel> source, Rectangle bounds)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        Configuration configuration = source.GetConfiguration();
+        Configuration configuration = source.Configuration;
 
         var interest = Rectangle.Intersect(bounds, source.Bounds());
         int startY = interest.Y;

src/ImageSharp/Processing/Extensions/ProcessingExtensions.cs

@@ -22,7 +22,7 @@ public static partial class ProcessingExtensions
     /// <exception cref="ObjectDisposedException">The source has been disposed.</exception>
     /// <exception cref="ImageProcessingException">The processing operation failed.</exception>
     public static void Mutate(this Image source, Action<IImageProcessingContext> operation)
-        => Mutate(source, source.GetConfiguration(), operation);
+        => Mutate(source, source.Configuration, operation);
 
     /// <summary>
     /// Mutates the source image by applying the image operation to it.
@@ -57,7 +57,7 @@ public static partial class ProcessingExtensions
     /// <exception cref="ImageProcessingException">The processing operation failed.</exception>
     public static void Mutate<TPixel>(this Image<TPixel> source, Action<IImageProcessingContext> operation)
         where TPixel : unmanaged, IPixel<TPixel>
-        => Mutate(source, source.GetConfiguration(), operation);
+        => Mutate(source, source.Configuration, operation);
 
     /// <summary>
     /// Mutates the source image by applying the image operation to it.
@@ -97,7 +97,7 @@ public static partial class ProcessingExtensions
     /// <exception cref="ImageProcessingException">The processing operation failed.</exception>
     public static void Mutate<TPixel>(this Image<TPixel> source, params IImageProcessor[] operations)
         where TPixel : unmanaged, IPixel<TPixel>
-        => Mutate(source, source.GetConfiguration(), operations);
+        => Mutate(source, source.Configuration, operations);
 
     /// <summary>
     /// Mutates the source image by applying the operations to it.
@@ -135,7 +135,7 @@ public static partial class ProcessingExtensions
     /// <exception cref="ObjectDisposedException">The source has been disposed.</exception>
     /// <exception cref="ImageProcessingException">The processing operation failed.</exception>
     public static Image Clone(this Image source, Action<IImageProcessingContext> operation)
-        => Clone(source, source.GetConfiguration(), operation);
+        => Clone(source, source.Configuration, operation);
 
     /// <summary>
     /// Creates a deep clone of the current image. The clone is then mutated by the given operation.
@@ -174,7 +174,7 @@ public static partial class ProcessingExtensions
     /// <returns>The new <see cref="Image{TPixel}"/>.</returns>
     public static Image<TPixel> Clone<TPixel>(this Image<TPixel> source, Action<IImageProcessingContext> operation)
         where TPixel : unmanaged, IPixel<TPixel>
-        => Clone(source, source.GetConfiguration(), operation);
+        => Clone(source, source.Configuration, operation);
 
     /// <summary>
     /// Creates a deep clone of the current image. The clone is then mutated by the given operation.
@@ -217,7 +217,7 @@ public static partial class ProcessingExtensions
     /// <returns>The new <see cref="Image{TPixel}"/></returns>
     public static Image<TPixel> Clone<TPixel>(this Image<TPixel> source, params IImageProcessor[] operations)
         where TPixel : unmanaged, IPixel<TPixel>
-        => Clone(source, source.GetConfiguration(), operations);
+        => Clone(source, source.Configuration, operations);
 
     /// <summary>
     /// Creates a deep clone of the current image. The clone is then mutated by the given operations.

src/ImageSharp/Processing/Processors/Quantization/WuQuantizer{TPixel}.cs

@@ -111,7 +111,7 @@ internal struct WuQuantizer<TPixel> : IQuantizer<TPixel>
     public QuantizerOptions Options { get; }
 
     /// <inheritdoc/>
-    public ReadOnlyMemory<TPixel> Palette
+    public readonly ReadOnlyMemory<TPixel> Palette
     {
         get
         {
@@ -362,7 +362,7 @@ internal struct WuQuantizer<TPixel> : IQuantizer<TPixel>
     /// </summary>
     /// <param name="source">The source data.</param>
     /// <param name="bounds">The bounds within the source image to quantize.</param>
-    private void Build3DHistogram(Buffer2D<TPixel> source, Rectangle bounds)
+    private readonly void Build3DHistogram(Buffer2D<TPixel> source, Rectangle bounds)
     {
         Span<Moment> momentSpan = this.momentsOwner.GetSpan();
 
@@ -393,7 +393,7 @@ internal struct WuQuantizer<TPixel> : IQuantizer<TPixel>
     /// Converts the histogram into moments so that we can rapidly calculate the sums of the above quantities over any desired box.
     /// </summary>
     /// <param name="allocator">The memory allocator used for allocating buffers.</param>
-    private void Get3DMoments(MemoryAllocator allocator)
+    private readonly void Get3DMoments(MemoryAllocator allocator)
     {
         using IMemoryOwner<Moment> volume = allocator.Allocate<Moment>(IndexCount * IndexAlphaCount);
         using IMemoryOwner<Moment> area = allocator.Allocate<Moment>(IndexAlphaCount);
@@ -462,7 +462,7 @@ internal struct WuQuantizer<TPixel> : IQuantizer<TPixel>
     /// </summary>
     /// <param name="cube">The cube.</param>
     /// <returns>The <see cref="float"/>.</returns>
-    private double Variance(ref Box cube)
+    private readonly double Variance(ref Box cube)
     {
         ReadOnlySpan<Moment> momentSpan = this.momentsOwner.GetSpan();
 
@@ -503,7 +503,7 @@ internal struct WuQuantizer<TPixel> : IQuantizer<TPixel>
     /// <param name="cut">The cutting point.</param>
     /// <param name="whole">The whole moment.</param>
     /// <returns>The <see cref="float"/>.</returns>
-    private float Maximize(ref Box cube, int direction, int first, int last, out int cut, Moment whole)
+    private readonly float Maximize(ref Box cube, int direction, int first, int last, out int cut, Moment whole)
     {
         ReadOnlySpan<Moment> momentSpan = this.momentsOwner.GetSpan();
         Moment bottom = Bottom(ref cube, direction, momentSpan);
@@ -634,7 +634,7 @@ internal struct WuQuantizer<TPixel> : IQuantizer<TPixel>
     /// </summary>
     /// <param name="cube">The cube.</param>
     /// <param name="label">A label.</param>
-    private void Mark(ref Box cube, byte label)
+    private readonly void Mark(ref Box cube, byte label)
     {
         Span<byte> tagSpan = this.tagsOwner.GetSpan();
 

src/ImageSharp/Processing/Processors/Transforms/EntropyCropProcessor{TPixel}.cs

@@ -38,7 +38,7 @@ internal class EntropyCropProcessor<TPixel> : ImageProcessor<TPixel>
         // All frames have be the same size so we only need to calculate the correct dimensions for the first frame
         using (Image<TPixel> temp = new(this.Configuration, this.Source.Metadata.DeepClone(), new[] { this.Source.Frames.RootFrame.Clone() }))
         {
-            Configuration configuration = this.Source.GetConfiguration();
+            Configuration configuration = this.Source.Configuration;
 
             // Detect the edges.
             new EdgeDetector2DProcessor(KnownEdgeDetectorKernels.Sobel, false).Execute(this.Configuration, temp, this.SourceRectangle);

tests/ImageSharp.Tests/Color/ColorTests.cs

@@ -18,25 +18,42 @@ public partial class ColorTests
         Assert.Equal(expected, (Rgba32)c2);
     }
 
-    [Fact]
+    [Theory]
-    public void Equality_WhenTrue()
+    [InlineData(false)]
+    [InlineData(true)]
+    public void Equality_WhenTrue(bool highPrecision)
     {
         Color c1 = new Rgba64(100, 2000, 3000, 40000);
         Color c2 = new Rgba64(100, 2000, 3000, 40000);
 
+        if (highPrecision)
+        {
+            c1 = Color.FromPixel(c1.ToPixel<RgbaVector>());
+            c2 = Color.FromPixel(c2.ToPixel<RgbaVector>());
+        }
+
         Assert.True(c1.Equals(c2));
         Assert.True(c1 == c2);
         Assert.False(c1 != c2);
         Assert.True(c1.GetHashCode() == c2.GetHashCode());
     }
 
-    [Fact]
+    [Theory]
-    public void Equality_WhenFalse()
+    [InlineData(false)]
+    [InlineData(true)]
+    public void Equality_WhenFalse(bool highPrecision)
     {
         Color c1 = new Rgba64(100, 2000, 3000, 40000);
         Color c2 = new Rgba64(101, 2000, 3000, 40000);
         Color c3 = new Rgba64(100, 2000, 3000, 40001);
 
+        if (highPrecision)
+        {
+            c1 = Color.FromPixel(c1.ToPixel<RgbaVector>());
+            c2 = Color.FromPixel(c2.ToPixel<RgbaVector>());
+            c3 = Color.FromPixel(c3.ToPixel<RgbaVector>());
+        }
+
         Assert.False(c1.Equals(c2));
         Assert.False(c2.Equals(c3));
         Assert.False(c3.Equals(c1));
@@ -47,13 +64,20 @@ public partial class ColorTests
         Assert.False(c1.Equals(null));
     }
 
-    [Fact]
+    [Theory]
-    public void ToHex()
+    [InlineData(false)]
+    [InlineData(true)]
+    public void ToHex(bool highPrecision)
     {
         string expected = "ABCD1234";
-        var color = Color.ParseHex(expected);
+        Color color = Color.ParseHex(expected);
-        string actual = color.ToHex();
 
+        if (highPrecision)
+        {
+            color = Color.FromPixel(color.ToPixel<RgbaVector>());
+        }
+
+        string actual = color.ToHex();
         Assert.Equal(expected, actual);
     }
 

tests/ImageSharp.Tests/Formats/Pbm/PbmDecoderTests.cs

@@ -1,9 +1,11 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Text;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Pbm;
 using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Tests.TestUtilities;
 using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
 using static SixLabors.ImageSharp.Tests.TestImages.Pbm;
 
@@ -120,4 +122,23 @@ public class PbmDecoderTests
             testOutputDetails: details,
             appendPixelTypeToFileName: false);
     }
+
+    [Fact]
+    public void PlainText_PrematureEof()
+    {
+        byte[] bytes = Encoding.ASCII.GetBytes($"P1\n100 100\n1 0 1 0 1 0");
+        using EofHitCounter eofHitCounter = EofHitCounter.RunDecoder(bytes);
+
+        Assert.True(eofHitCounter.EofHitCount <= 2);
+        Assert.Equal(new Size(100, 100), eofHitCounter.Image.Size);
+    }
+
+    [Fact]
+    public void Binary_PrematureEof()
+    {
+        using EofHitCounter eofHitCounter = EofHitCounter.RunDecoder(RgbBinaryPrematureEof);
+
+        Assert.True(eofHitCounter.EofHitCount <= 2);
+        Assert.Equal(new Size(29, 30), eofHitCounter.Image.Size);
+    }
 }

tests/ImageSharp.Tests/Formats/Pbm/PbmMetadataTests.cs

@@ -83,12 +83,9 @@ public class PbmMetadataTests
     }
 
     [Fact]
-    public void Identify_HandlesCraftedDenialOfServiceString()
+    public void Identify_EofInHeader_ThrowsInvalidImageContentException()
     {
         byte[] bytes = Convert.FromBase64String("UDEjWAAACQAAAAA=");
-        ImageInfo info = Image.Identify(bytes);
+        Assert.Throws<InvalidImageContentException>(() => Image.Identify(bytes));
-        Assert.Equal(default, info.Size);
-        Configuration.Default.ImageFormatsManager.TryFindFormatByFileExtension("pbm", out IImageFormat format);
-        Assert.Equal(format!, info.Metadata.DecodedImageFormat);
     }
 }

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

@@ -7,7 +7,6 @@ using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
-using SixLabors.ImageSharp.Processing.Processors.Quantization;
 using SixLabors.ImageSharp.Tests.TestUtilities;
 using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
 using SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs;
@@ -79,6 +78,18 @@ public partial class PngDecoderTests
         { TestImages.Png.Rgba64Bpp, typeof(Image<Rgba64>) },
     };
 
+    public static readonly string[] MultiFrameTestFiles =
+    {
+        TestImages.Png.APng,
+        TestImages.Png.SplitIDatZeroLength,
+        TestImages.Png.DisposeNone,
+        TestImages.Png.DisposeBackground,
+        TestImages.Png.DisposeBackgroundRegion,
+        TestImages.Png.DisposePreviousFirst,
+        TestImages.Png.DisposeBackgroundBeforeRegion,
+        TestImages.Png.BlendOverMultiple
+    };
+
     [Theory]
     [MemberData(nameof(PixelFormatRange))]
     public void Decode_NonGeneric_CreatesCorrectImageType(string path, Type type)
@@ -107,6 +118,19 @@ public partial class PngDecoderTests
         image.CompareToOriginal(provider, ImageComparer.Exact);
     }
 
+    [Theory]
+    [WithFileCollection(nameof(MultiFrameTestFiles), PixelTypes.Rgba32)]
+    public void Decode_VerifyAllFrames<TPixel>(TestImageProvider<TPixel> provider)
+    where TPixel : unmanaged, IPixel<TPixel>
+    {
+        using Image<TPixel> image = provider.GetImage(PngDecoder.Instance);
+
+        // Some images have many frames, only compare a selection of them.
+        static bool Predicate(int i, int _) => i <= 8 || i % 8 == 0;
+        image.DebugSaveMultiFrame(provider, predicate: Predicate);
+        image.CompareToReferenceOutputMultiFrame(provider, ImageComparer.Exact, predicate: Predicate);
+    }
+
     [Theory]
     [WithFile(TestImages.Png.Splash, PixelTypes.Rgba32)]
     public void PngDecoder_Decode_Resize<TPixel>(TestImageProvider<TPixel> provider)
@@ -539,7 +563,8 @@ public partial class PngDecoderTests
     {
         using Image<TPixel> image = provider.GetImage(PngDecoder.Instance);
         PngMetadata metadata = image.Metadata.GetPngMetadata();
-        Assert.True(metadata.HasTransparency);
+        Assert.NotNull(metadata.ColorTable);
+        Assert.Contains(metadata.ColorTable.Value.ToArray(), x => x.ToRgba32().A < 255);
     }
 
     // https://github.com/SixLabors/ImageSharp/issues/2209
@@ -551,7 +576,8 @@ public partial class PngDecoderTests
         using MemoryStream stream = new(testFile.Bytes, false);
         ImageInfo imageInfo = Image.Identify(stream);
         PngMetadata metadata = imageInfo.Metadata.GetPngMetadata();
-        Assert.True(metadata.HasTransparency);
+        Assert.NotNull(metadata.ColorTable);
+        Assert.Contains(metadata.ColorTable.Value.ToArray(), x => x.ToRgba32().A < 255);
     }
 
     // https://github.com/SixLabors/ImageSharp/issues/410

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

@@ -442,6 +442,40 @@ public partial class PngEncoderTests
         });
     }
 
+    [Theory]
+    [WithFile(TestImages.Png.APng, PixelTypes.Rgba32)]
+    public void Encode_APng<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        using Image<TPixel> image = provider.GetImage(PngDecoder.Instance);
+        using MemoryStream memStream = new();
+        image.Save(memStream, PngEncoder);
+        memStream.Position = 0;
+
+        image.DebugSave(provider: provider, encoder: PngEncoder, null, false);
+
+        using Image<Rgba32> output = Image.Load<Rgba32>(memStream);
+        ImageComparer.Exact.VerifySimilarity(output, image);
+
+        Assert.Equal(5, image.Frames.Count);
+        Assert.Equal(image.Frames.Count, output.Frames.Count);
+
+        PngMetadata originalMetadata = image.Metadata.GetPngMetadata();
+        PngMetadata outputMetadata = output.Metadata.GetPngMetadata();
+
+        Assert.Equal(originalMetadata.RepeatCount, outputMetadata.RepeatCount);
+
+        for (int i = 0; i < image.Frames.Count; i++)
+        {
+            PngFrameMetadata originalFrameMetadata = image.Frames[i].Metadata.GetPngFrameMetadata();
+            PngFrameMetadata outputFrameMetadata = output.Frames[i].Metadata.GetPngFrameMetadata();
+
+            Assert.Equal(originalFrameMetadata.FrameDelay, outputFrameMetadata.FrameDelay);
+            Assert.Equal(originalFrameMetadata.BlendMethod, outputFrameMetadata.BlendMethod);
+            Assert.Equal(originalFrameMetadata.DisposalMethod, outputFrameMetadata.DisposalMethod);
+        }
+    }
+
     [Theory]
     [MemberData(nameof(PngTrnsFiles))]
     public void Encode_PreserveTrns(string imagePath, PngBitDepth pngBitDepth, PngColorType pngColorType)
@@ -449,44 +483,17 @@ public partial class PngEncoderTests
         TestFile testFile = TestFile.Create(imagePath);
         using Image<Rgba32> input = testFile.CreateRgba32Image();
         PngMetadata inMeta = input.Metadata.GetPngMetadata();
-        Assert.True(inMeta.HasTransparency);
+        Assert.True(inMeta.TransparentColor.HasValue);
 
         using MemoryStream memStream = new();
         input.Save(memStream, PngEncoder);
         memStream.Position = 0;
         using Image<Rgba32> output = Image.Load<Rgba32>(memStream);
         PngMetadata outMeta = output.Metadata.GetPngMetadata();
-        Assert.True(outMeta.HasTransparency);
+        Assert.True(outMeta.TransparentColor.HasValue);
-
+        Assert.Equal(inMeta.TransparentColor, outMeta.TransparentColor);
-        switch (pngColorType)
+        Assert.Equal(pngBitDepth, outMeta.BitDepth);
-        {
+        Assert.Equal(pngColorType, outMeta.ColorType);
-            case PngColorType.Grayscale:
-                if (pngBitDepth.Equals(PngBitDepth.Bit16))
-                {
-                    Assert.True(outMeta.TransparentL16.HasValue);
-                    Assert.Equal(inMeta.TransparentL16, outMeta.TransparentL16);
-                }
-                else
-                {
-                    Assert.True(outMeta.TransparentL8.HasValue);
-                    Assert.Equal(inMeta.TransparentL8, outMeta.TransparentL8);
-                }
-
-                break;
-            case PngColorType.Rgb:
-                if (pngBitDepth.Equals(PngBitDepth.Bit16))
-                {
-                    Assert.True(outMeta.TransparentRgb48.HasValue);
-                    Assert.Equal(inMeta.TransparentRgb48, outMeta.TransparentRgb48);
-                }
-                else
-                {
-                    Assert.True(outMeta.TransparentRgb24.HasValue);
-                    Assert.Equal(inMeta.TransparentRgb24, outMeta.TransparentRgb24);
-                }
-
-                break;
-        }
     }
 
     [Theory]

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

@@ -0,0 +1,35 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Formats.Png;
+
+namespace SixLabors.ImageSharp.Tests.Formats.Png;
+
+[Trait("Format", "Png")]
+public class PngFrameMetadataTests
+{
+    [Fact]
+    public void CloneIsDeep()
+    {
+        PngFrameMetadata meta = new()
+        {
+            FrameDelay = new(1, 0),
+            DisposalMethod = PngDisposalMethod.Background,
+            BlendMethod = PngBlendMethod.Over,
+        };
+
+        PngFrameMetadata clone = (PngFrameMetadata)meta.DeepClone();
+
+        Assert.True(meta.FrameDelay.Equals(clone.FrameDelay));
+        Assert.True(meta.DisposalMethod.Equals(clone.DisposalMethod));
+        Assert.True(meta.BlendMethod.Equals(clone.BlendMethod));
+
+        clone.FrameDelay = new(2, 1);
+        clone.DisposalMethod = PngDisposalMethod.Previous;
+        clone.BlendMethod = PngBlendMethod.Source;
+
+        Assert.False(meta.FrameDelay.Equals(clone.FrameDelay));
+        Assert.False(meta.DisposalMethod.Equals(clone.DisposalMethod));
+        Assert.False(meta.BlendMethod.Equals(clone.BlendMethod));
+    }
+}

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

@@ -3,6 +3,7 @@
 
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.Formats.Png.Chunks;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 using SixLabors.ImageSharp.PixelFormats;
@@ -30,15 +31,25 @@ public class PngMetadataTests
             ColorType = PngColorType.GrayscaleWithAlpha,
             InterlaceMethod = PngInterlaceMode.Adam7,
             Gamma = 2,
-            TextData = new List<PngTextData> { new PngTextData("name", "value", "foo", "bar") }
+            TextData = new List<PngTextData> { new PngTextData("name", "value", "foo", "bar") },
+            RepeatCount = 123
         };
 
         PngMetadata clone = (PngMetadata)meta.DeepClone();
 
+        Assert.True(meta.BitDepth == clone.BitDepth);
+        Assert.True(meta.ColorType == clone.ColorType);
+        Assert.True(meta.InterlaceMethod == clone.InterlaceMethod);
+        Assert.True(meta.Gamma.Equals(clone.Gamma));
+        Assert.False(meta.TextData.Equals(clone.TextData));
+        Assert.True(meta.TextData.SequenceEqual(clone.TextData));
+        Assert.True(meta.RepeatCount == clone.RepeatCount);
+
         clone.BitDepth = PngBitDepth.Bit2;
         clone.ColorType = PngColorType.Palette;
         clone.InterlaceMethod = PngInterlaceMode.None;
         clone.Gamma = 1;
+        clone.RepeatCount = 321;
 
         Assert.False(meta.BitDepth == clone.BitDepth);
         Assert.False(meta.ColorType == clone.ColorType);
@@ -46,6 +57,7 @@ public class PngMetadataTests
         Assert.False(meta.Gamma.Equals(clone.Gamma));
         Assert.False(meta.TextData.Equals(clone.TextData));
         Assert.True(meta.TextData.SequenceEqual(clone.TextData));
+        Assert.False(meta.RepeatCount == clone.RepeatCount);
     }
 
     [Theory]

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

@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
-using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.Formats.Png.Chunks;
 
 namespace SixLabors.ImageSharp.Tests.Formats.Png;
 

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

@@ -2,7 +2,6 @@
 // Licensed under the Six Labors Split License.
 
 // ReSharper disable InconsistentNaming
-using System.Runtime.InteropServices;
 using System.Runtime.Intrinsics.X86;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Tiff;
@@ -666,6 +665,33 @@ public class TiffDecoderTests : TiffDecoderBaseTester
     public void TiffDecoder_CanDecode_TiledWithNonEqualWidthAndHeight<TPixel>(TestImageProvider<TPixel> provider)
         where TPixel : unmanaged, IPixel<TPixel> => TestTiffDecoder(provider);
 
+    [Theory]
+    [WithFile(JpegCompressedGray0000539558, PixelTypes.Rgba32)]
+    public void TiffDecoder_ThrowsException_WithCircular_IFD_Offsets<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel>
+        => Assert.Throws<ImageFormatException>(
+            () =>
+            {
+                using (provider.GetImage(TiffDecoder.Instance))
+                {
+                }
+            });
+
+    [Theory]
+    [WithFile(Tiled0000023664, PixelTypes.Rgba32)]
+    public void TiffDecoder_CanDecode_TiledWithBadZlib<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        using Image<TPixel> image = provider.GetImage(TiffDecoder.Instance);
+
+        // ImageMagick cannot decode this image.
+        image.DebugSave(provider);
+        image.CompareToReferenceOutput(
+            ImageComparer.Exact,
+            provider,
+            appendPixelTypeToFileName: false);
+    }
+
     [Theory]
     [WithFileCollection(nameof(MultiframeTestImages), PixelTypes.Rgba32)]
     public void DecodeMultiframe<TPixel>(TestImageProvider<TPixel> provider)

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

@@ -1,7 +1,6 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
-using System.Runtime.InteropServices;
 using System.Runtime.Intrinsics.X86;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Webp;
@@ -340,6 +339,24 @@ public class WebpDecoderTests
         Assert.Equal(1, image.Frames.Count);
     }
 
+    [Theory]
+    [WithFile(Lossy.AnimatedIssue2528, PixelTypes.Rgba32)]
+    public void Decode_AnimatedLossy_IgnoreBackgroundColor_Works<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        WebpDecoderOptions options = new()
+        {
+            BackgroundColorHandling = BackgroundColorHandling.Ignore,
+            GeneralOptions = new DecoderOptions()
+            {
+                MaxFrames = 1
+            }
+        };
+        using Image<TPixel> image = provider.GetImage(WebpDecoder.Instance, options);
+        image.DebugSave(provider);
+        image.CompareToOriginal(provider, ReferenceDecoder);
+    }
+
     [Theory]
     [WithFile(Lossless.LossLessCorruptImage1, PixelTypes.Rgba32)]
     [WithFile(Lossless.LossLessCorruptImage2, PixelTypes.Rgba32)]

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

@@ -42,7 +42,7 @@ public class YuvConversionTests
     {
         // arrange
         using Image<TPixel> image = provider.GetImage();
-        Configuration config = image.GetConfiguration();
+        Configuration config = image.Configuration;
         MemoryAllocator memoryAllocator = config.MemoryAllocator;
         int pixels = image.Width * image.Height;
         int uvWidth = (image.Width + 1) >> 1;
@@ -158,7 +158,7 @@ public class YuvConversionTests
     {
         // arrange
         using Image<TPixel> image = provider.GetImage();
-        Configuration config = image.GetConfiguration();
+        Configuration config = image.Configuration;
         MemoryAllocator memoryAllocator = config.MemoryAllocator;
         int pixels = image.Width * image.Height;
         int uvWidth = (image.Width + 1) >> 1;

tests/ImageSharp.Tests/Image/ImageFrameCollectionTests.NonGeneric.cs

@@ -20,7 +20,7 @@ public abstract partial class ImageFrameCollectionTests
         public void AddFrame_OfDifferentPixelType()
         {
             using (Image<Bgra32> sourceImage = new(
-                this.Image.GetConfiguration(),
+                this.Image.Configuration,
                 this.Image.Width,
                 this.Image.Height,
                 Color.Blue))
@@ -41,7 +41,7 @@ public abstract partial class ImageFrameCollectionTests
         public void InsertFrame_OfDifferentPixelType()
         {
             using (Image<Bgra32> sourceImage = new(
-                this.Image.GetConfiguration(),
+                this.Image.Configuration,
                 this.Image.Width,
                 this.Image.Height,
                 Color.Blue))
@@ -278,8 +278,8 @@ public abstract partial class ImageFrameCollectionTests
             where TPixel : unmanaged, IPixel<TPixel>
         {
             using Image source = provider.GetImage();
-            using Image<TPixel> dest = new(source.GetConfiguration(), source.Width, source.Height);
+            using Image<TPixel> dest = new(source.Configuration, source.Width, source.Height);
-
+            
             // Giphy.gif has 5 frames
             ImportFrameAs<Bgra32>(source.Frames, dest.Frames, 0);
             ImportFrameAs<Argb32>(source.Frames, dest.Frames, 1);

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

@@ -70,7 +70,7 @@ public partial class ImageTests
         {
             using Image<Rgba32> image = new(5, 5);
             string ext = Path.GetExtension(filename);
-            image.GetConfiguration().ImageFormatsManager.TryFindFormatByFileExtension(ext, out IImageFormat format);
+            image.Configuration.ImageFormatsManager.TryFindFormatByFileExtension(ext, out IImageFormat format);
             Assert.Equal(mimeType, format!.DefaultMimeType);
 
             using MemoryStream stream = new();

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

@@ -136,7 +136,7 @@ public partial class ImageTests
                 ref Rgba32 pixel0 = ref imageMem.Span[0];
                 Assert.True(Unsafe.AreSame(ref array[0], ref pixel0));
 
-                Assert.Equal(cfg, image.GetConfiguration());
+                Assert.Equal(cfg, image.Configuration);
                 Assert.Equal(metaData, image.Metadata);
             }
         }
@@ -239,7 +239,7 @@ public partial class ImageTests
                 ref Rgba32 pixel0 = ref imageMem.Span[0];
                 Assert.True(Unsafe.AreSame(ref Unsafe.As<byte, Rgba32>(ref array[0]), ref pixel0));
 
-                Assert.Equal(cfg, image.GetConfiguration());
+                Assert.Equal(cfg, image.Configuration);
                 Assert.Equal(metaData, image.Metadata);
             }
         }
@@ -336,7 +336,7 @@ public partial class ImageTests
                     ref Rgba32 pixel_1 = ref imageSpan[imageSpan.Length - 1];
                     Assert.True(Unsafe.AreSame(ref array[array.Length - 1], ref pixel_1));
 
-                    Assert.Equal(cfg, image.GetConfiguration());
+                    Assert.Equal(cfg, image.Configuration);
                     Assert.Equal(metaData, image.Metadata);
                 }
             }

tests/ImageSharp.Tests/Image/ImageTests.cs

@@ -6,6 +6,7 @@ using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Jpeg;
 using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.ImageSharp.Tests.Memory;
@@ -31,10 +32,14 @@ public partial class ImageTests
                 Assert.Equal(11 * 23, imageMem.Length);
                 image.ComparePixelBufferTo(default(Rgba32));
 
-                Assert.Equal(Configuration.Default, image.GetConfiguration());
+                Assert.Equal(Configuration.Default, image.Configuration);
             }
         }
 
+        [Fact]
+        public void Width_Height_SizeNotRepresentable_ThrowsInvalidImageOperationException()
+            => Assert.Throws<InvalidMemoryOperationException>(() => new Image<Rgba32>(int.MaxValue, int.MaxValue));
+
         [Fact]
         public void Configuration_Width_Height()
         {
@@ -48,7 +53,7 @@ public partial class ImageTests
                 Assert.Equal(11 * 23, imageMem.Length);
                 image.ComparePixelBufferTo(default(Rgba32));
 
-                Assert.Equal(configuration, image.GetConfiguration());
+                Assert.Equal(configuration, image.Configuration);
             }
         }
 
@@ -66,7 +71,7 @@ public partial class ImageTests
                 Assert.Equal(11 * 23, imageMem.Length);
                 image.ComparePixelBufferTo(color);
 
-                Assert.Equal(configuration, image.GetConfiguration());
+                Assert.Equal(configuration, image.Configuration);
             }
         }
 
@@ -83,7 +88,7 @@ public partial class ImageTests
             {
                 Assert.Equal(21, image.Width);
                 Assert.Equal(22, image.Height);
-                Assert.Same(configuration, image.GetConfiguration());
+                Assert.Same(configuration, image.Configuration);
                 Assert.Same(metadata, image.Metadata);
 
                 Assert.Equal(dirtyValue, image[5, 5].PackedValue);

tests/ImageSharp.Tests/Memory/Allocators/UniformUnmanagedPoolMemoryAllocatorTests.cs

@@ -107,6 +107,13 @@ public class UniformUnmanagedPoolMemoryAllocatorTests
         }
     }
 
+    [Fact]
+    public void AllocateGroup_SizeInBytesOverLongMaxValue_ThrowsInvalidMemoryOperationException()
+    {
+        var allocator = new UniformUnmanagedMemoryPoolMemoryAllocator(null);
+        Assert.Throws<InvalidMemoryOperationException>(() => allocator.AllocateGroup<S4>(int.MaxValue * (long)int.MaxValue, int.MaxValue));
+    }
+
     [Fact]
     public unsafe void Allocate_MemoryIsPinnableMultipleTimes()
     {

tests/ImageSharp.Tests/Metadata/Profiles/Exif/Values/ExifValuesTests.cs

@@ -70,8 +70,7 @@ public class ExifValuesTests
         { ExifTag.JPEGDCTables },
         { ExifTag.JPEGACTables },
         { ExifTag.StripRowCounts },
-        { ExifTag.IntergraphRegisters },
+        { ExifTag.IntergraphRegisters }
-        { ExifTag.TimeZoneOffset }
     };
 
     public static TheoryData<ExifTag> NumberTags => new TheoryData<ExifTag>
@@ -129,6 +128,7 @@ public class ExifValuesTests
         { ExifTag.GPSImgDirection },
         { ExifTag.GPSDestBearing },
         { ExifTag.GPSDestDistance },
+        { ExifTag.GPSHPositioningError },
     };
 
     public static TheoryData<ExifTag> RationalArrayTags => new TheoryData<ExifTag>
@@ -235,6 +235,11 @@ public class ExifValuesTests
         { ExifTag.Decode }
     };
 
+    public static TheoryData<ExifTag> SignedShortArrayTags => new TheoryData<ExifTag>
+    {
+        { ExifTag.TimeZoneOffset }
+    };
+
     public static TheoryData<ExifTag> StringTags => new TheoryData<ExifTag>
     {
         { ExifTag.ImageDescription },
@@ -559,6 +564,21 @@ public class ExifValuesTests
         Assert.Equal(expected, typed.Value);
     }
 
+
+    [Theory]
+    [MemberData(nameof(SignedShortArrayTags))]
+    public void ExifSignedShortArrayTests(ExifTag tag)
+    {
+        short[] expected = new short[] { 21, 42 };
+        ExifValue value = ExifValues.Create(tag);
+
+        Assert.False(value.TrySetValue(expected.ToString()));
+        Assert.True(value.TrySetValue(expected));
+
+        var typed = (ExifSignedShortArray)value;
+        Assert.Equal(expected, typed.Value);
+    }
+
     [Theory]
     [MemberData(nameof(StringTags))]
     public void ExifStringTests(ExifTag tag)

tests/ImageSharp.Tests/Processing/BaseImageOperationsExtensionTest.cs

@@ -22,7 +22,7 @@ public abstract class BaseImageOperationsExtensionTest : IDisposable
         this.options = new GraphicsOptions { Antialias = false };
         this.source = new Image<Rgba32>(91 + 324, 123 + 56);
         this.rect = new Rectangle(91, 123, 324, 56); // make this random?
-        this.internalOperations = new FakeImageOperationsProvider.FakeImageOperations<Rgba32>(this.source.GetConfiguration(), this.source, false);
+        this.internalOperations = new FakeImageOperationsProvider.FakeImageOperations<Rgba32>(this.source.Configuration, this.source, false);
         this.internalOperations.SetGraphicsOptions(this.options);
         this.operations = this.internalOperations;
     }

tests/ImageSharp.Tests/Processing/Processors/Convolution/BokehBlurTest.cs

@@ -65,7 +65,7 @@ public class BokehBlurTest
 
         // Make sure the kernel components are the same
         using Image<Rgb24> image = new(1, 1);
-        Configuration configuration = image.GetConfiguration();
+        Configuration configuration = image.Configuration;
         BokehBlurProcessor definition = new(10, BokehBlurProcessor.DefaultComponents, BokehBlurProcessor.DefaultGamma);
 
         using BokehBlurProcessor<Rgb24> processor = (BokehBlurProcessor<Rgb24>)definition.CreatePixelSpecificProcessor(configuration, image, image.Bounds);

tests/ImageSharp.Tests/TestImages.cs

@@ -62,6 +62,17 @@ public static class TestImages
         public const string TestPattern31x31HalfTransparent = "Png/testpattern31x31-halftransparent.png";
         public const string XmpColorPalette = "Png/xmp-colorpalette.png";
 
+        // Animated
+        // https://philip.html5.org/tests/apng/tests.html
+        public const string APng = "Png/animated/apng.png";
+        public const string SplitIDatZeroLength = "Png/animated/4-split-idat-zero-length.png";
+        public const string DisposeNone = "Png/animated/7-dispose-none.png";
+        public const string DisposeBackground = "Png/animated/8-dispose-background.png";
+        public const string DisposeBackgroundBeforeRegion = "Png/animated/14-dispose-background-before-region.png";
+        public const string DisposeBackgroundRegion = "Png/animated/15-dispose-background-region.png";
+        public const string DisposePreviousFirst = "Png/animated/12-dispose-prev-first.png";
+        public const string BlendOverMultiple = "Png/animated/21-blend-over-multiple.png";
+
         // Filtered test images from http://www.schaik.com/pngsuite/pngsuite_fil_png.html
         public const string Filter0 = "Png/filter0.png";
         public const string SubFilter3BytesPerPixel = "Png/filter1.png";
@@ -688,6 +699,7 @@ public static class TestImages
             public const string WithXmp = "Webp/xmp_lossy.webp";
             public const string BikeSmall = "Webp/bike_lossy_small.webp";
             public const string Animated = "Webp/leo_animated_lossy.webp";
+            public const string AnimatedIssue2528 = "Webp/issues/Issue2528.webp";
 
             // Lossy images without macroblock filtering.
             public const string BikeWithExif = "Webp/bike_lossy_with_exif.webp";
@@ -990,6 +1002,8 @@ public static class TestImages
         public const string Issues2149 = "Tiff/Issues/Group4CompressionWithStrips.tiff";
         public const string Issues2255 = "Tiff/Issues/Issue2255.png";
         public const string Issues2435 = "Tiff/Issues/Issue2435.tiff";
+        public const string JpegCompressedGray0000539558 = "Tiff/Issues/JpegCompressedGray-0000539558.tiff";
+        public const string Tiled0000023664 = "Tiff/Issues/tiled-0000023664.tiff";
 
         public const string SmallRgbDeflate = "Tiff/rgb_small_deflate.tiff";
         public const string SmallRgbLzw = "Tiff/rgb_small_lzw.tiff";
@@ -1051,6 +1065,7 @@ public static class TestImages
         public const string GrayscalePlainNormalized = "Pbm/grayscale_plain_normalized.pgm";
         public const string GrayscalePlainMagick = "Pbm/grayscale_plain_magick.pgm";
         public const string RgbBinary = "Pbm/00000_00000.ppm";
+        public const string RgbBinaryPrematureEof = "Pbm/00000_00000_premature_eof.ppm";
         public const string RgbPlain = "Pbm/rgb_plain.ppm";
         public const string RgbPlainNormalized = "Pbm/rgb_plain_normalized.ppm";
         public const string RgbPlainMagick = "Pbm/rgb_plain_magick.ppm";

tests/ImageSharp.Tests/TestUtilities/EofHitCounter.cs

@@ -0,0 +1,36 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.IO;
+
+namespace SixLabors.ImageSharp.Tests.TestUtilities;
+
+internal class EofHitCounter : IDisposable
+{
+    private readonly BufferedReadStream stream;
+
+    public EofHitCounter(BufferedReadStream stream, Image image)
+    {
+        this.stream = stream;
+        this.Image = image;
+    }
+
+    public int EofHitCount => this.stream.EofHitCount;
+
+    public Image Image { get; private set; }
+
+    public static EofHitCounter RunDecoder(string testImage) => RunDecoder(TestFile.Create(testImage).Bytes);
+
+    public static EofHitCounter RunDecoder(byte[] imageData)
+    {
+        BufferedReadStream stream = new(Configuration.Default, new MemoryStream(imageData));
+        Image image = Image.Load(stream);
+        return new EofHitCounter(stream, image);
+    }
+
+    public void Dispose()
+    {
+        this.stream.Dispose();
+        this.Image.Dispose();
+    }
+}

tests/ImageSharp.Tests/TestUtilities/ImageComparison/ExactImageComparer.cs

@@ -28,7 +28,7 @@ public class ExactImageComparer : ImageComparer
         var bBuffer = new Rgba64[width];
 
         var differences = new List<PixelDifference>();
-        Configuration configuration = expected.GetConfiguration();
+        Configuration configuration = expected.Configuration;
         Buffer2D<TPixelA> expectedBuffer = expected.PixelBuffer;
         Buffer2D<TPixelB> actualBuffer = actual.PixelBuffer;