universal metadata parsing methods for loading and identify

src/ImageSharp/Formats/Tiff/TiffDecoderCore.cs

@@ -164,6 +164,7 @@ internal class TiffDecoderCore : IImageDecoderInternals
         where TPixel : unmanaged, IPixel<TPixel>
     {
         var frames = new List<ImageFrame<TPixel>>();
+        var framesMetadata = new List<ImageFrameMetadata>();
         try
         {
             this.inputStream = stream;
@@ -179,6 +180,7 @@ internal class TiffDecoderCore : IImageDecoderInternals
                 cancellationToken.ThrowIfCancellationRequested();
                 ImageFrame<TPixel> frame = this.DecodeFrame<TPixel>(ifd, cancellationToken);
                 frames.Add(frame);
+                framesMetadata.Add(frame.Metadata);
 
                 if (++frameCount == this.maxFrames)
                 {
@@ -186,9 +188,7 @@ internal class TiffDecoderCore : IImageDecoderInternals
                 }
             }
 
-            ImageMetadata metadata = TiffDecoderMetadataCreator.Create(frames, this.skipMetadata, reader.ByteOrder, reader.IsBigTiff);
-
-            TiffDecoderMetadataCreator.FillFrames(metadata.GetTiffMetadata(), directories);
+            ImageMetadata metadata = TiffDecoderMetadataCreator.Create(framesMetadata, this.skipMetadata, reader.ByteOrder, reader.IsBigTiff);
 
             // TODO: Tiff frames can have different sizes.
             ImageFrame<TPixel> root = frames[0];
@@ -221,17 +221,21 @@ internal class TiffDecoderCore : IImageDecoderInternals
         DirectoryReader reader = new(stream, this.configuration.MemoryAllocator);
         IList<ExifProfile> directories = reader.Read();
 
-        ExifProfile rootFrameExifProfile = directories.First();
-        TiffFrameMetadata rootMetadata = TiffFrameMetadata.Parse(rootFrameExifProfile);
+        var frames = new List<ImageFrameMetadata>();
+        foreach (ExifProfile dir in directories)
+        {
+            var frame = this.CreateFrameMetadata(dir);
+            frames.Add(frame);
+        }
 
-        ImageMetadata metadata = TiffDecoderMetadataCreator.Create(reader.ByteOrder, reader.IsBigTiff, rootFrameExifProfile);
+        ExifProfile rootFrameExifProfile = directories.First();
 
-        TiffDecoderMetadataCreator.FillFrames(metadata.GetTiffMetadata(), directories);
+        ImageMetadata metadata = TiffDecoderMetadataCreator.Create(frames, this.skipMetadata, reader.ByteOrder, reader.IsBigTiff);
 
         int width = GetImageWidth(rootFrameExifProfile);
         int height = GetImageHeight(rootFrameExifProfile);
 
-        return new ImageInfo(new PixelTypeInfo((int)rootMetadata.BitsPerPixel), width, height, metadata);
+        return new ImageInfo(new PixelTypeInfo((int)frames.First().GetTiffMetadata().BitsPerPixel), width, height, metadata);
     }
 
     /// <summary>
@@ -244,16 +248,8 @@ internal class TiffDecoderCore : IImageDecoderInternals
     private ImageFrame<TPixel> DecodeFrame<TPixel>(ExifProfile tags, CancellationToken cancellationToken)
         where TPixel : unmanaged, IPixel<TPixel>
     {
-        ImageFrameMetadata imageFrameMetaData = new();
-        if (!this.skipMetadata)
-        {
-            imageFrameMetaData.ExifProfile = tags;
-        }
-
-        TiffFrameMetadata tiffFrameMetaData = imageFrameMetaData.GetTiffMetadata();
-        TiffFrameMetadata.Parse(tiffFrameMetaData, tags);
-
-        bool isTiled = this.VerifyAndParse(tags, tiffFrameMetaData);
+        var imageFrameMetaData = this.CreateFrameMetadata(tags);
+        bool isTiled = this.VerifyAndParse(tags, imageFrameMetaData.GetTiffMetadata());
 
         int width = GetImageWidth(tags);
         int height = GetImageHeight(tags);
@@ -271,6 +267,19 @@ internal class TiffDecoderCore : IImageDecoderInternals
         return frame;
     }
 
+    private ImageFrameMetadata CreateFrameMetadata(ExifProfile tags)
+    {
+        ImageFrameMetadata imageFrameMetaData = new();
+        if (!this.skipMetadata)
+        {
+            imageFrameMetaData.ExifProfile = tags;
+        }
+
+        TiffFrameMetadata.Parse(imageFrameMetaData.GetTiffMetadata(), tags);
+
+        return imageFrameMetaData;
+    }
+
     /// <summary>
     /// Decodes the image data for Tiff's which arrange the pixel data in stripes.
     /// </summary>

src/ImageSharp/Formats/Tiff/TiffDecoderMetadataCreator.cs

@@ -8,7 +8,6 @@ using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 using SixLabors.ImageSharp.Metadata.Profiles.Icc;
 using SixLabors.ImageSharp.Metadata.Profiles.Iptc;
 using SixLabors.ImageSharp.Metadata.Profiles.Xmp;
-using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats.Tiff;
 
@@ -17,22 +16,21 @@ namespace SixLabors.ImageSharp.Formats.Tiff;
 /// </summary>
 internal static class TiffDecoderMetadataCreator
 {
-    public static ImageMetadata Create<TPixel>(List<ImageFrame<TPixel>> frames, bool ignoreMetadata, ByteOrder byteOrder, bool isBigTiff)
-        where TPixel : unmanaged, IPixel<TPixel>
+    public static ImageMetadata Create(List<ImageFrameMetadata> frames, bool ignoreMetadata, ByteOrder byteOrder, bool isBigTiff)
     {
         if (frames.Count < 1)
         {
             TiffThrowHelper.ThrowImageFormatException("Expected at least one frame.");
         }
 
-        ImageMetadata imageMetaData = Create(byteOrder, isBigTiff, frames[0].Metadata.ExifProfile);
+        ImageMetadata imageMetaData = Create(byteOrder, isBigTiff, frames[0].ExifProfile);
 
         if (!ignoreMetadata)
         {
+            var tiffMetadata = imageMetaData.GetTiffMetadata();
             for (int i = 0; i < frames.Count; i++)
             {
-                ImageFrame<TPixel> frame = frames[i];
-                ImageFrameMetadata frameMetaData = frame.Metadata;
+                ImageFrameMetadata frameMetaData = frames[i];
                 if (TryGetIptc(frameMetaData.ExifProfile.Values, out byte[] iptcBytes))
                 {
                     frameMetaData.IptcProfile = new IptcProfile(iptcBytes);
@@ -47,13 +45,15 @@ internal static class TiffDecoderMetadataCreator
                 {
                     frameMetaData.IccProfile = new IccProfile(iccProfileBytes.Value);
                 }
+
+                tiffMetadata.Frames.Add(frameMetaData.GetTiffMetadata());
             }
         }
 
         return imageMetaData;
     }
 
-    public static ImageMetadata Create(ByteOrder byteOrder, bool isBigTiff, ExifProfile exifProfile)
+    private static ImageMetadata Create(ByteOrder byteOrder, bool isBigTiff, ExifProfile exifProfile)
     {
         var imageMetaData = new ImageMetadata();
         SetResolution(imageMetaData, exifProfile);
@@ -64,16 +64,6 @@ internal static class TiffDecoderMetadataCreator
         return imageMetaData;
     }
 
-    public static void FillFrames(TiffMetadata tiffMetadata, IList<ExifProfile> directories)
-    {
-        foreach (ExifProfile dir in directories)
-        {
-            TiffFrameMetadata meta = TiffFormat.Instance.CreateDefaultFormatFrameMetadata();
-            TiffFrameMetadata.Parse(meta, dir);
-            tiffMetadata.Frames.Add(meta);
-        }
-    }
-
     private static void SetResolution(ImageMetadata imageMetaData, ExifProfile exifProfile)
     {
         imageMetaData.ResolutionUnits = exifProfile != null ? UnitConverter.ExifProfileToResolutionUnit(exifProfile) : PixelResolutionUnit.PixelsPerInch;