Add Header

src/ImageSharp/Formats/Ani/AniDecoder.cs

@@ -0,0 +1,35 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Ani;
+
+internal sealed class AniDecoder : ImageDecoder
+{
+    private AniDecoder()
+    {
+    }
+
+    /// <summary>
+    /// Gets the shared instance.
+    /// </summary>
+    public static AniDecoder Instance { get; } = new();
+
+    protected override Image<TPixel> Decode<TPixel>(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
+    {
+        Guard.NotNull(options, nameof(options));
+        Guard.NotNull(stream, nameof(stream));
+        Image<TPixel> image = new AniDecoderCore(options).Decode<TPixel>(options.Configuration, stream, cancellationToken);
+        ScaleToTargetSize(options, image);
+        return image;
+    }
+
+    protected override Image Decode(DecoderOptions options, Stream stream, CancellationToken cancellationToken) => this.Decode<Rgba32>(options, stream, cancellationToken);
+
+    protected override ImageInfo Identify(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
+    {
+        Guard.NotNull(options, nameof(options));
+        Guard.NotNull(stream, nameof(stream));
+        return new AniDecoderCore(options).Identify(options.Configuration, stream, cancellationToken);
+    }
+}

src/ImageSharp/Formats/Ani/AniDecoderCore.cs

@@ -0,0 +1,35 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Formats.Icon;
+using SixLabors.ImageSharp.IO;
+
+namespace SixLabors.ImageSharp.Formats.Ani;
+
+internal class AniDecoderCore : ImageDecoderCore
+{
+    public AniDecoderCore(DecoderOptions options)
+        : base(options)
+    {
+    }
+
+    protected override Image<TPixel> Decode<TPixel>(BufferedReadStream stream, CancellationToken cancellationToken)
+    {
+        this.ReadHeader(stream);
+        throw new NotImplementedException();
+    }
+
+    protected override ImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken)
+    {
+        throw new NotImplementedException();
+    }
+
+    private void ReadHeader(Stream stream)
+    {
+        // Skip the identifier
+        stream.Skip(12);
+        Span<byte> buffer = stackalloc byte[AniHeader.Size];
+        _ = stream.Read(buffer);
+        AniHeader header = AniHeader.Parse(buffer);
+    }
+}

src/ImageSharp/Formats/Ani/AniHeader.cs

@@ -0,0 +1,34 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using System.Runtime.InteropServices;
+
+namespace SixLabors.ImageSharp.Formats.Ani;
+
+[StructLayout(LayoutKind.Sequential, Pack = 1, Size = Size)]
+internal readonly struct AniHeader
+{
+    public const int Size = 36;
+
+    public ushort Frames { get; }
+
+    public ushort Steps { get; }
+
+    public ushort Width { get; }
+
+    public ushort Height { get; }
+
+    public ushort BitCount { get; }
+
+    public ushort Planes { get; }
+
+    public ushort DisplayRate { get; }
+
+    public ushort Flags { get; }
+
+    public static AniHeader Parse(in ReadOnlySpan<byte> data)
+    => MemoryMarshal.Cast<byte, AniHeader>(data)[0];
+
+    public readonly unsafe void WriteTo(in Stream stream)
+    => stream.Write(MemoryMarshal.Cast<AniHeader, byte>([this]));
+}

src/ImageSharp/Formats/Ani/AniMetadata.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Ani;
+
+internal class AniMetadata : IFormatMetadata<AniMetadata>
+{
+
+    public static AniMetadata FromFormatConnectingMetadata(FormatConnectingMetadata metadata) => throw new NotImplementedException();
+
+    public void AfterImageApply<TPixel>(Image<TPixel> destination)
+        where TPixel : unmanaged, IPixel<TPixel> => throw new NotImplementedException();
+
+    public IDeepCloneable DeepClone() => throw new NotImplementedException();
+
+    public PixelTypeInfo GetPixelTypeInfo() => throw new NotImplementedException();
+
+    public FormatConnectingMetadata ToFormatConnectingMetadata() => throw new NotImplementedException();
+
+    AniMetadata IDeepCloneable<AniMetadata>.DeepClone() => throw new NotImplementedException();
+}