Implement GifFrameMetadata

src/ImageSharp/Formats/Bmp/BmpMetadata.cs

@@ -138,8 +138,8 @@ public class BmpMetadata : IFormatMetadata<BmpMetadata>, IFormatFrameMetadata<Bm
         => new();
 
     /// <inheritdoc/>
-    public IDeepCloneable DeepClone() => ((IDeepCloneable<BmpMetadata>)this).DeepClone();
+    IDeepCloneable IDeepCloneable.DeepClone() => this.DeepClone();
 
     /// <inheritdoc/>
-    BmpMetadata IDeepCloneable<BmpMetadata>.DeepClone() => new(this);
+    public BmpMetadata DeepClone() => new(this);
 }

src/ImageSharp/Formats/Gif/GifDecoderCore.cs

@@ -517,7 +517,7 @@ internal sealed class GifDecoderCore : IImageDecoderInternals
         }
         else
         {
-            if (this.graphicsControlExtension.DisposalMethod == GifDisposalMethod.RestoreToPrevious)
+            if (this.graphicsControlExtension.DisposalMethod == FrameDisposalMode.RestoreToPrevious)
             {
                 prevFrame = previousFrame;
             }
@@ -624,7 +624,7 @@ internal sealed class GifDecoderCore : IImageDecoderInternals
 
         previousFrame = currentFrame ?? image.Frames.RootFrame;
 
-        if (this.graphicsControlExtension.DisposalMethod == GifDisposalMethod.RestoreToBackground)
+        if (this.graphicsControlExtension.DisposalMethod == FrameDisposalMode.RestoreToBackground)
         {
             this.restoreArea = new Rectangle(descriptor.Left, descriptor.Top, descriptor.Width, descriptor.Height);
         }

src/ImageSharp/Formats/Gif/GifDisposalMethod.cs

@@ -1,37 +0,0 @@
-// Copyright (c) Six Labors.
-// Licensed under the Six Labors Split License.
-
-namespace SixLabors.ImageSharp.Formats.Gif;
-
-/// <summary>
-/// Provides enumeration for instructing the decoder what to do with the last image
-/// in an animation sequence.
-/// <see href="http://www.w3.org/Graphics/GIF/spec-gif89a.txt"/> section 23
-/// </summary>
-public enum GifDisposalMethod
-{
-    /// <summary>
-    /// No disposal specified.
-    /// The decoder is not required to take any action.
-    /// </summary>
-    Unspecified = 0,
-
-    /// <summary>
-    /// Do not dispose.
-    /// The graphic is to be left in place.
-    /// </summary>
-    NotDispose = 1,
-
-    /// <summary>
-    /// Restore to background color.
-    /// The area used by the graphic must be restored to the background color.
-    /// </summary>
-    RestoreToBackground = 2,
-
-    /// <summary>
-    /// Restore to previous.
-    /// The decoder is required to restore the area overwritten by the
-    /// graphic with what was there prior to rendering the graphic.
-    /// </summary>
-    RestoreToPrevious = 3
-}

src/ImageSharp/Formats/Gif/GifEncoderCore.cs

@@ -235,7 +235,7 @@ internal sealed class GifEncoderCore : IImageEncoderInternals
         Image<TPixel> image,
         ReadOnlyMemory<TPixel> globalPalette,
         int globalTransparencyIndex,
-        GifDisposalMethod previousDisposalMethod)
+        FrameDisposalMode previousDisposalMode)
         where TPixel : unmanaged, IPixel<TPixel>
     {
         if (image.Frames.Count == 1)
@@ -279,10 +279,10 @@ internal sealed class GifEncoderCore : IImageEncoderInternals
                 useLocal,
                 gifMetadata,
                 paletteQuantizer,
-                previousDisposalMethod);
+                previousDisposalMode);
 
             previousFrame = currentFrame;
-            previousDisposalMethod = gifMetadata.DisposalMethod;
+            previousDisposalMode = gifMetadata.DisposalMethod;
         }
 
         if (hasPaletteQuantizer)
@@ -323,14 +323,14 @@ internal sealed class GifEncoderCore : IImageEncoderInternals
         bool useLocal,
         GifFrameMetadata metadata,
         PaletteQuantizer<TPixel> globalPaletteQuantizer,
-        GifDisposalMethod previousDisposal)
+        FrameDisposalMode previousDisposalMode)
         where TPixel : unmanaged, IPixel<TPixel>
     {
         // Capture any explicit transparency index from the metadata.
         // We use it to determine the value to use to replace duplicate pixels.
         int transparencyIndex = metadata.HasTransparency ? metadata.TransparencyIndex : -1;
 
-        ImageFrame<TPixel>? previous = previousDisposal == GifDisposalMethod.RestoreToBackground ? null : previousFrame;
+        ImageFrame<TPixel>? previous = previousDisposalMode == FrameDisposalMode.RestoreToBackground ? null : previousFrame;
 
         // Deduplicate and quantize the frame capturing only required parts.
         (bool difference, Rectangle bounds) =
@@ -664,7 +664,7 @@ internal sealed class GifEncoderCore : IImageEncoderInternals
         bool hasTransparency = metadata.HasTransparency;
 
         byte packedValue = GifGraphicControlExtension.GetPackedValue(
-            disposalMethod: metadata.DisposalMethod,
+            disposalMode: metadata.DisposalMethod,
             transparencyFlag: hasTransparency);
 
         GifGraphicControlExtension extension = new(

src/ImageSharp/Formats/Gif/GifFrameMetadata.cs

@@ -9,7 +9,7 @@ namespace SixLabors.ImageSharp.Formats.Gif;
 /// <summary>
 /// Provides Gif specific metadata information for the image frame.
 /// </summary>
-public class GifFrameMetadata : IDeepCloneable
+public class GifFrameMetadata : IFormatFrameMetadata<GifFrameMetadata>
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="GifFrameMetadata"/> class.
@@ -73,10 +73,65 @@ public class GifFrameMetadata : IDeepCloneable
     /// Primarily used in Gif animation, this field indicates the way in which the graphic is to
     /// be treated after being displayed.
     /// </summary>
-    public GifDisposalMethod DisposalMethod { get; set; }
+    public FrameDisposalMode DisposalMethod { get; set; }
+
+    /// <inheritdoc />
+    public static GifFrameMetadata FromFormatConnectingFrameMetadata(FormatConnectingFrameMetadata metadata)
+    {
+        int index = -1;
+        const float background = 1f;
+        if (metadata.ColorTable.HasValue)
+        {
+            ReadOnlySpan<Color> colorTable = metadata.ColorTable.Value.Span;
+            for (int i = 0; i < colorTable.Length; i++)
+            {
+                Vector4 vector = colorTable[i].ToScaledVector4();
+                if (vector.W < background)
+                {
+                    index = i;
+                }
+            }
+        }
+
+        bool hasTransparency = index >= 0;
+
+        return new()
+        {
+            LocalColorTable = metadata.ColorTable,
+            ColorTableMode = metadata.ColorTableMode,
+            FrameDelay = (int)Math.Round(metadata.Duration.TotalMilliseconds / 10),
+            DisposalMethod = metadata.DisposalMode,
+            HasTransparency = hasTransparency,
+            TransparencyIndex = hasTransparency ? unchecked((byte)index) : byte.MinValue,
+        };
+    }
+
+    /// <inheritdoc />
+    public FormatConnectingFrameMetadata ToFormatConnectingFrameMetadata()
+    {
+        // throw new NotImplementedException();
+        // For most scenarios we would consider the blend method to be 'Over' however if a frame has a disposal method of 'RestoreToBackground' or
+        // has a local palette with 256 colors and is not transparent we should use 'Source'.
+        bool blendSource = this.DisposalMethod == FrameDisposalMode.RestoreToBackground || (this.LocalColorTable?.Length == 256 && !this.HasTransparency);
+
+        // If the color table is global and frame has no transparency. Consider it 'Source' also.
+        blendSource |= this.ColorTableMode == FrameColorTableMode.Global && !this.HasTransparency;
+
+        return new()
+        {
+            ColorTable = this.LocalColorTable,
+            ColorTableMode = this.ColorTableMode,
+            Duration = TimeSpan.FromMilliseconds(this.FrameDelay * 10),
+            DisposalMode = this.DisposalMethod,
+            BlendMode = blendSource ? FrameBlendMode.Source : FrameBlendMode.Over,
+        };
+    }
+
+    /// <inheritdoc/>
+    IDeepCloneable IDeepCloneable.DeepClone() => this.DeepClone();
 
     /// <inheritdoc/>
-    public IDeepCloneable DeepClone() => new GifFrameMetadata(this);
+    public GifFrameMetadata DeepClone() => new(this);
 
     internal static GifFrameMetadata FromAnimatedMetadata(AnimatedImageFrameMetadata metadata)
     {
@@ -103,17 +158,9 @@ public class GifFrameMetadata : IDeepCloneable
             LocalColorTable = metadata.ColorTable,
             ColorTableMode = metadata.ColorTableMode,
             FrameDelay = (int)Math.Round(metadata.Duration.TotalMilliseconds / 10),
-            DisposalMethod = GetMode(metadata.DisposalMode),
+            DisposalMethod = metadata.DisposalMode,
             HasTransparency = hasTransparency,
             TransparencyIndex = hasTransparency ? unchecked((byte)index) : byte.MinValue,
         };
     }
-
-    private static GifDisposalMethod GetMode(FrameDisposalMode mode) => mode switch
-    {
-        FrameDisposalMode.DoNotDispose => GifDisposalMethod.NotDispose,
-        FrameDisposalMode.RestoreToBackground => GifDisposalMethod.RestoreToBackground,
-        FrameDisposalMode.RestoreToPrevious => GifDisposalMethod.RestoreToPrevious,
-        _ => GifDisposalMethod.Unspecified,
-    };
 }

src/ImageSharp/Formats/Gif/GifMetadata.cs

@@ -145,8 +145,8 @@ public class GifMetadata : IFormatMetadata<GifMetadata>
     }
 
     /// <inheritdoc/>
-    public IDeepCloneable DeepClone() => ((IDeepCloneable<GifMetadata>)this).DeepClone();
+    IDeepCloneable IDeepCloneable.DeepClone() => this.DeepClone();
 
     /// <inheritdoc/>
-    GifMetadata IDeepCloneable<GifMetadata>.DeepClone() => new(this);
+    public GifMetadata DeepClone() => new(this);
 }

src/ImageSharp/Formats/Gif/MetadataExtensions.cs

@@ -80,7 +80,7 @@ public static partial class MetadataExtensions
     {
         // For most scenarios we would consider the blend method to be 'Over' however if a frame has a disposal method of 'RestoreToBackground' or
         // has a local palette with 256 colors and is not transparent we should use 'Source'.
-        bool blendSource = source.DisposalMethod == GifDisposalMethod.RestoreToBackground || (source.LocalColorTable?.Length == 256 && !source.HasTransparency);
+        bool blendSource = source.DisposalMethod == FrameDisposalMode.RestoreToBackground || (source.LocalColorTable?.Length == 256 && !source.HasTransparency);
 
         // If the color table is global and frame has no transparency. Consider it 'Source' also.
         blendSource |= source.ColorTableMode == FrameColorTableMode.Global && !source.HasTransparency;
@@ -90,16 +90,8 @@ public static partial class MetadataExtensions
             ColorTable = source.LocalColorTable,
             ColorTableMode = source.ColorTableMode,
             Duration = TimeSpan.FromMilliseconds(source.FrameDelay * 10),
-            DisposalMode = GetMode(source.DisposalMethod),
+            DisposalMode = source.DisposalMethod,
             BlendMode = blendSource ? FrameBlendMode.Source : FrameBlendMode.Over,
         };
     }
-
-    private static FrameDisposalMode GetMode(GifDisposalMethod method) => method switch
-    {
-        GifDisposalMethod.NotDispose => FrameDisposalMode.DoNotDispose,
-        GifDisposalMethod.RestoreToBackground => FrameDisposalMode.RestoreToBackground,
-        GifDisposalMethod.RestoreToPrevious => FrameDisposalMode.RestoreToPrevious,
-        _ => FrameDisposalMode.Unspecified,
-    };
 }

src/ImageSharp/Formats/Gif/Sections/GifGraphicControlExtension.cs

@@ -52,7 +52,7 @@ internal readonly struct GifGraphicControlExtension : IGifExtension, IEquatable<
     /// Gets the disposal method which indicates the way in which the
     /// graphic is to be treated after being displayed.
     /// </summary>
-    public GifDisposalMethod DisposalMethod => (GifDisposalMethod)((this.Packed & 0x1C) >> 2);
+    public FrameDisposalMode DisposalMethod => (FrameDisposalMode)((this.Packed & 0x1C) >> 2);
 
     /// <summary>
     /// Gets a value indicating whether transparency flag is to be set.
@@ -80,7 +80,7 @@ internal readonly struct GifGraphicControlExtension : IGifExtension, IEquatable<
     public static GifGraphicControlExtension Parse(ReadOnlySpan<byte> buffer)
         => MemoryMarshal.Cast<byte, GifGraphicControlExtension>(buffer)[0];
 
-    public static byte GetPackedValue(GifDisposalMethod disposalMethod, bool userInputFlag = false, bool transparencyFlag = false)
+    public static byte GetPackedValue(FrameDisposalMode disposalMode, bool userInputFlag = false, bool transparencyFlag = false)
     {
         /*
         Reserved               | 3 Bits
@@ -91,7 +91,7 @@ internal readonly struct GifGraphicControlExtension : IGifExtension, IEquatable<
 
         byte value = 0;
 
-        value |= (byte)((int)disposalMethod << 2);
+        value |= (byte)((int)disposalMode << 2);
 
         if (userInputFlag)
         {

tests/ImageSharp.Tests/Formats/Gif/GifEncoderTests.cs

@@ -309,11 +309,11 @@ public class GifEncoderTests
             switch (pngF.DisposalMethod)
             {
                 case PngDisposalMethod.RestoreToBackground:
-                    Assert.Equal(GifDisposalMethod.RestoreToBackground, gifF.DisposalMethod);
+                    Assert.Equal(FrameDisposalMode.RestoreToBackground, gifF.DisposalMethod);
                     break;
                 case PngDisposalMethod.DoNotDispose:
                 default:
-                    Assert.Equal(GifDisposalMethod.NotDispose, gifF.DisposalMethod);
+                    Assert.Equal(FrameDisposalMode.DoNotDispose, gifF.DisposalMethod);
                     break;
             }
         }
@@ -359,11 +359,11 @@ public class GifEncoderTests
             switch (webpF.DisposalMethod)
             {
                 case WebpDisposalMethod.RestoreToBackground:
-                    Assert.Equal(GifDisposalMethod.RestoreToBackground, gifF.DisposalMethod);
+                    Assert.Equal(FrameDisposalMode.RestoreToBackground, gifF.DisposalMethod);
                     break;
                 case WebpDisposalMethod.DoNotDispose:
                 default:
-                    Assert.Equal(GifDisposalMethod.NotDispose, gifF.DisposalMethod);
+                    Assert.Equal(FrameDisposalMode.DoNotDispose, gifF.DisposalMethod);
                     break;
             }
         }

tests/ImageSharp.Tests/Formats/Gif/GifFrameMetadataTests.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Gif;
 
 namespace SixLabors.ImageSharp.Tests.Formats.Gif;
@@ -14,14 +15,14 @@ public class GifFrameMetadataTests
         GifFrameMetadata meta = new()
         {
             FrameDelay = 1,
-            DisposalMethod = GifDisposalMethod.RestoreToBackground,
+            DisposalMethod = FrameDisposalMode.RestoreToBackground,
             LocalColorTable = new[] { Color.Black, Color.White }
         };
 
         GifFrameMetadata clone = (GifFrameMetadata)meta.DeepClone();
 
         clone.FrameDelay = 2;
-        clone.DisposalMethod = GifDisposalMethod.RestoreToPrevious;
+        clone.DisposalMethod = FrameDisposalMode.RestoreToPrevious;
         clone.LocalColorTable = new[] { Color.Black };
 
         Assert.False(meta.FrameDelay.Equals(clone.FrameDelay));

tests/ImageSharp.Tests/Formats/Gif/GifMetadataTests.cs

@@ -183,14 +183,14 @@ public class GifMetadataTests
     }
 
     [Theory]
-    [InlineData(TestImages.Gif.Cheers, 93, FrameColorTableMode.Global, 256, 4, GifDisposalMethod.NotDispose)]
+    [InlineData(TestImages.Gif.Cheers, 93, FrameColorTableMode.Global, 256, 4, FrameDisposalMode.DoNotDispose)]
     public void Identify_Frames(
         string imagePath,
         int framesCount,
         FrameColorTableMode colorTableMode,
         int globalColorTableLength,
         int frameDelay,
-        GifDisposalMethod disposalMethod)
+        FrameDisposalMode disposalMethod)
     {
         TestFile testFile = TestFile.Create(imagePath);
         using MemoryStream stream = new(testFile.Bytes, false);

tests/ImageSharp.Tests/Formats/Gif/Sections/GifGraphicControlExtensionTests.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Gif;
 
 namespace SixLabors.ImageSharp.Tests.Formats.Gif.Sections;
@@ -10,9 +11,9 @@ public class GifGraphicControlExtensionTests
     [Fact]
     public void TestPackedValue()
     {
-        Assert.Equal(0, GifGraphicControlExtension.GetPackedValue(GifDisposalMethod.Unspecified, false, false));
-        Assert.Equal(11, GifGraphicControlExtension.GetPackedValue(GifDisposalMethod.RestoreToBackground, true, true));
-        Assert.Equal(4, GifGraphicControlExtension.GetPackedValue(GifDisposalMethod.NotDispose, false, false));
-        Assert.Equal(14, GifGraphicControlExtension.GetPackedValue(GifDisposalMethod.RestoreToPrevious, true, false));
+        Assert.Equal(0, GifGraphicControlExtension.GetPackedValue(FrameDisposalMode.Unspecified, false, false));
+        Assert.Equal(11, GifGraphicControlExtension.GetPackedValue(FrameDisposalMode.RestoreToBackground, true, true));
+        Assert.Equal(4, GifGraphicControlExtension.GetPackedValue(FrameDisposalMode.DoNotDispose, false, false));
+        Assert.Equal(14, GifGraphicControlExtension.GetPackedValue(FrameDisposalMode.RestoreToPrevious, true, false));
     }
 }

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

@@ -521,14 +521,14 @@ public partial class PngEncoderTests
 
             switch (gifF.DisposalMethod)
             {
-                case GifDisposalMethod.RestoreToBackground:
+                case FrameDisposalMode.RestoreToBackground:
                     Assert.Equal(PngDisposalMethod.RestoreToBackground, pngF.DisposalMethod);
                     break;
-                case GifDisposalMethod.RestoreToPrevious:
+                case FrameDisposalMode.RestoreToPrevious:
                     Assert.Equal(PngDisposalMethod.RestoreToPrevious, pngF.DisposalMethod);
                     break;
-                case GifDisposalMethod.Unspecified:
-                case GifDisposalMethod.NotDispose:
+                case FrameDisposalMode.Unspecified:
+                case FrameDisposalMode.DoNotDispose:
                 default:
                     Assert.Equal(PngDisposalMethod.DoNotDispose, pngF.DisposalMethod);
                     break;

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

@@ -2,6 +2,7 @@
 // Licensed under the Six Labors Split License.
 
 using System.Runtime.InteropServices;
+using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Formats.Webp;
@@ -96,12 +97,12 @@ public class WebpEncoderTests
 
             switch (gifF.DisposalMethod)
             {
-                case GifDisposalMethod.RestoreToBackground:
+                case FrameDisposalMode.RestoreToBackground:
                     Assert.Equal(WebpDisposalMethod.RestoreToBackground, webpF.DisposalMethod);
                     break;
-                case GifDisposalMethod.RestoreToPrevious:
-                case GifDisposalMethod.Unspecified:
-                case GifDisposalMethod.NotDispose:
+                case FrameDisposalMode.RestoreToPrevious:
+                case FrameDisposalMode.Unspecified:
+                case FrameDisposalMode.DoNotDispose:
                 default:
                     Assert.Equal(WebpDisposalMethod.DoNotDispose, webpF.DisposalMethod);
                     break;

tests/ImageSharp.Tests/Metadata/ImageFrameMetadataTests.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.Metadata.Profiles.Icc;
@@ -21,7 +22,7 @@ public class ImageFrameMetadataTests
     {
         const int frameDelay = 42;
         const int colorTableLength = 128;
-        const GifDisposalMethod disposalMethod = GifDisposalMethod.RestoreToBackground;
+        const FrameDisposalMode disposalMethod = FrameDisposalMode.RestoreToBackground;
 
         ImageFrameMetadata metaData = new();
         GifFrameMetadata gifFrameMetadata = metaData.GetGifMetadata();