Rename SaveComment to SetComment, add index, add clearcomments

Author: RobertMut

src/ImageSharp/Formats/Jpeg/MetadataExtensions.cs

@@ -20,22 +20,35 @@ public static partial class MetadataExtensions
     public static JpegMetadata GetJpegMetadata(this ImageMetadata metadata) => metadata.GetFormatMetadata(JpegFormat.Instance);
 
     /// <summary>
-    /// Saves the comment into <see cref="JpegMetadata"/>
+    /// Sets the comment in <see cref="JpegMetadata"/>
     /// </summary>
     /// <param name="metadata">The metadata this method extends.</param>
+    /// <param name="index">The index of comment to be inserted to.</param>
     /// <param name="comment">The comment string.</param>
-    public static void SaveComment(this JpegMetadata metadata, string comment)
+    public static void SetComment(this JpegMetadata metadata, int index, string comment)
     {
-        ASCIIEncoding encoding = new();
+        if (metadata.Comments == null)
+        {
+            return;
+        }
 
+        ASCIIEncoding encoding = new();
         byte[] bytes = encoding.GetBytes(comment);
-        metadata.Comments?.Add(encoding.GetChars(bytes));
+        List<Memory<char>>? comments = metadata.Comments as List<Memory<char>>;
+        comments?.Insert(index, encoding.GetChars(bytes));
     }
 
     /// <summary>
     /// Gets the comments from <see cref="JpegMetadata"/>
     /// </summary>
     /// <param name="metadata">The metadata this method extends.</param>
+    /// <param name="index">The index of comment.</param>
     /// <returns>The IEnumerable string of comments.</returns>
-    public static IEnumerable<string>? GetComments(this JpegMetadata metadata) => metadata.Comments?.Select(x => x.ToString());
+    public static string? GetComment(this JpegMetadata metadata, int index) => metadata.Comments?.ElementAtOrDefault(index).ToString();
+
+    /// <summary>
+    /// Clears comments
+    /// </summary>
+    /// <param name="metadata">The <see cref="JpegMetadata"/>.</param>
+    public static void ClearComments(this JpegMetadata metadata) => metadata.Comments?.Clear();
 }

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

@@ -425,6 +425,21 @@ public void EncodedStringTags_Read()
         VerifyEncodedStrings(exif);
     }
 
+    [Theory]
+    [WithFile(TestImages.Jpeg.Issues.Issue2067_CommentMarker, PixelTypes.Rgba32)]
+    public void JpegDecoder_DecodeMetadataComment<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        string expectedComment = "TEST COMMENT";
+        using Image<TPixel> image = provider.GetImage(JpegDecoder.Instance);
+        JpegMetadata metadata = image.Metadata.GetJpegMetadata();
+
+        Assert.Equal(1, metadata.Comments?.Count);
+        Assert.Equal(expectedComment, metadata.GetComment(0));
+        image.DebugSave(provider);
+        image.CompareToOriginal(provider);
+    }
+
     private static void VerifyEncodedStrings(ExifProfile exif)
     {
         Assert.NotNull(exif);

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

@@ -364,19 +364,4 @@ public void Issue2517_DecodeWorks<TPixel>(TestImageProvider<TPixel> provider)
         image.DebugSave(provider);
         image.CompareToOriginal(provider);
     }
-
-    [Theory]
-    [WithFile(TestImages.Jpeg.Issues.Issue2067_CommentMarker, PixelTypes.Rgba32)]
-    public void JpegDecoder_DecodeMetadataComment<TPixel>(TestImageProvider<TPixel> provider)
-        where TPixel : unmanaged, IPixel<TPixel>
-    {
-        string expectedComment = "TEST COMMENT";
-        using Image<TPixel> image = provider.GetImage(JpegDecoder.Instance);
-        JpegMetadata metadata = image.Metadata.GetJpegMetadata();
-
-        Assert.Equal(1, metadata.Comments?.Count);
-        Assert.Equal(expectedComment, metadata.GetComments()?.FirstOrDefault());
-        image.DebugSave(provider);
-        image.CompareToOriginal(provider);
-    }
 }

tests/ImageSharp.Tests/Formats/Jpg/JpegEncoderTests.Metadata.cs

@@ -184,18 +184,18 @@ public void Encode_SavesMultipleComments()
         using var memStream = new MemoryStream();
 
         // act
-        meta.SaveComment("First comment");
-        meta.SaveComment("Second Comment");
+        meta.SetComment(0, "First comment");
+        meta.SetComment(1, "Second Comment");
         input.Save(memStream, JpegEncoder);
 
         // assert
         memStream.Position = 0;
         using var output = Image.Load<Rgba32>(memStream);
         JpegMetadata actual = output.Metadata.GetJpegMetadata();
         Assert.NotEmpty(actual.Comments);
-        Assert.Equal(2, actual.Comments.Count);
-        Assert.Equal(meta.Comments.ElementAt(0).ToString(), actual.Comments.ElementAt(0).ToString());
-        Assert.Equal(meta.Comments.ElementAt(1).ToString(), actual.Comments.ElementAt(1).ToString());
+        Assert.Equal(2, actual.Comments?.Count);
+        Assert.Equal(meta.Comments?.ElementAt(0).ToString(), actual.Comments?.ElementAt(0).ToString());
+        Assert.Equal(meta.Comments?.ElementAt(1).ToString(), actual.Comments?.ElementAt(1).ToString());
     }
 
     [Theory]