Implemented the IDecoderOptions inside the gif decoder.

src/ImageSharp.Formats.Gif/GifDecoder.cs

@@ -17,7 +17,7 @@ namespace ImageSharp.Formats
         public void Decode<TColor>(Image<TColor> image, Stream stream, IDecoderOptions options)
             where TColor : struct, IPixel<TColor>
         {
-            new GifDecoderCore<TColor>().Decode(image, stream);
+            new GifDecoderCore<TColor>(options).Decode(image, stream);
         }
     }
 }

src/ImageSharp.Formats.Gif/GifDecoderCore.cs

@@ -8,6 +8,7 @@ namespace ImageSharp.Formats
     using System;
     using System.Buffers;
     using System.IO;
+    using System.Text;
 
     /// <summary>
     /// Performs the gif decoding operation.
@@ -21,6 +22,11 @@ namespace ImageSharp.Formats
         /// </summary>
         private readonly byte[] buffer = new byte[16];
 
+        /// <summary>
+        /// The decoder options.
+        /// </summary>
+        private readonly IDecoderOptions options;
+
         /// <summary>
         /// The image to decode the information to.
         /// </summary>
@@ -61,6 +67,15 @@ namespace ImageSharp.Formats
         /// </summary>
         private GifGraphicsControlExtension graphicsControlExtension;
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="GifDecoderCore{TColor}"/> class.
+        /// </summary>
+        /// <param name="options">The decoder options.</param>
+        public GifDecoderCore(IDecoderOptions options)
+        {
+            this.options = options ?? DecoderOptions.Default;
+        }
+
         /// <summary>
         /// Decodes the stream to the image.
         /// </summary>
@@ -225,25 +240,32 @@ namespace ImageSharp.Formats
         /// </summary>
         private void ReadComments()
         {
-            int flag;
+            int length;
 
-            while ((flag = this.currentStream.ReadByte()) != 0)
+            while ((length = this.currentStream.ReadByte()) != 0)
             {
-                if (flag > GifConstants.MaxCommentLength)
+                if (length > GifConstants.MaxCommentLength)
+                {
+                    throw new ImageFormatException($"Gif comment length '{length}' exceeds max '{GifConstants.MaxCommentLength}'");
+                }
+
+                if (this.options.IgnoreMetadata)
                 {
-                    throw new ImageFormatException($"Gif comment length '{flag}' exceeds max '{GifConstants.MaxCommentLength}'");
+                    this.currentStream.Seek(length, SeekOrigin.Current);
+                    continue;
                 }
 
-                byte[] flagBuffer = ArrayPool<byte>.Shared.Rent(flag);
+                byte[] commentsBuffer = ArrayPool<byte>.Shared.Rent(length);
 
                 try
                 {
-                    this.currentStream.Read(flagBuffer, 0, flag);
+                    this.currentStream.Read(commentsBuffer, 0, length);
-                    this.decodedImage.MetaData.Properties.Add(new ImageProperty("Comments", BitConverter.ToString(flagBuffer, 0, flag)));
+                    string comments = Encoding.GetEncoding("ASCII").GetString(commentsBuffer, 0, length);
+                    this.decodedImage.MetaData.Properties.Add(new ImageProperty("Comments", comments));
                 }
                 finally
                 {
-                    ArrayPool<byte>.Shared.Return(flagBuffer);
+                    ArrayPool<byte>.Shared.Return(commentsBuffer);
                 }
             }
         }

src/ImageSharp/Formats/DecoderOptions.cs

@@ -3,13 +3,27 @@
 // Licensed under the Apache License, Version 2.0.
 // </copyright>
 
-namespace ImageSharp.Formats
+namespace ImageSharp
 {
     /// <summary>
     /// Encapsulates the shared decoder options.
     /// </summary>
     public class DecoderOptions : IDecoderOptions
     {
+        /// <summary>
+        /// Gets the default decoder options
+        /// </summary>
+        public static DecoderOptions Default
+        {
+            get
+            {
+                return new DecoderOptions()
+                {
+                    IgnoreMetadata = false
+                };
+            }
+        }
+
         /// <summary>
         /// Gets or sets a value indicating whether the metadata should be ignored when the image is being decoded.
         /// </summary>

src/ImageSharp/Formats/IDecoderOptions.cs

@@ -3,7 +3,7 @@
 // Licensed under the Apache License, Version 2.0.
 // </copyright>
 
-namespace ImageSharp.Formats
+namespace ImageSharp
 {
     /// <summary>
     /// Encapsulates the shared decoder options.

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

@@ -0,0 +1,46 @@
+// <copyright file="GifDecoderCoreTests.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageSharp.Tests
+{
+    using Xunit;
+
+    public class GifDecoderCoreTests
+    {
+        [Fact]
+        public void Decode_IgnoreMetadataIsFalse_CommentsAreRead()
+        {
+            var options = new DecoderOptions()
+            {
+                IgnoreMetadata = false
+            };
+
+            TestFile testFile = TestFile.Create(TestImages.Gif.Rings);
+
+            using (Image image = new Image(testFile.FilePath, options))
+            {
+                Assert.Equal(1, image.MetaData.Properties.Count);
+                Assert.Equal("Comments", image.MetaData.Properties[0].Name);
+                Assert.Equal("ImageSharp", image.MetaData.Properties[0].Value);
+            }
+        }
+
+        [Fact]
+        public void Decode_IgnoreMetadataIsTrue_CommentsAreIgnored()
+        {
+            var options = new DecoderOptions()
+            {
+                IgnoreMetadata = true
+            };
+
+            TestFile testFile = TestFile.Create(TestImages.Gif.Rings);
+
+            using (Image image = new Image(testFile.FilePath, options))
+            {
+                Assert.Equal(0, image.MetaData.Properties.Count);
+            }
+        }
+    }
+}