Add IsBigTif flag property in metadata

src/ImageSharp/Formats/Tiff/Ifd/DirectoryReader.cs

@@ -29,6 +29,8 @@ namespace SixLabors.ImageSharp.Formats.Tiff
         /// </summary>
         public ByteOrder ByteOrder { get; private set; }
 
+        public bool IsBigTiff { get; private set; }
+
         /// <summary>
         /// Reads image file directories.
         /// </summary>
@@ -40,6 +42,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
             headerReader.ReadFileHeader();
 
             this.nextIfdOffset = headerReader.FirstIfdOffset;
+            this.IsBigTiff = headerReader.IsBigTiff;
 
             return this.ReadIfds(headerReader.IsBigTiff);
         }

src/ImageSharp/Formats/Tiff/TiffDecoderCore.cs

@@ -154,7 +154,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
                 frames.Add(frame);
             }
 
-            ImageMetadata metadata = TiffDecoderMetadataCreator.Create(frames, this.ignoreMetadata, reader.ByteOrder);
+            ImageMetadata metadata = TiffDecoderMetadataCreator.Create(frames, this.ignoreMetadata, reader.ByteOrder, reader.IsBigTiff);
 
             // TODO: Tiff frames can have different sizes
             ImageFrame<TPixel> root = frames[0];
@@ -180,7 +180,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
             ExifProfile rootFrameExifProfile = directories.First();
             var rootMetadata = TiffFrameMetadata.Parse(rootFrameExifProfile);
 
-            ImageMetadata metadata = TiffDecoderMetadataCreator.Create(reader.ByteOrder, rootFrameExifProfile);
+            ImageMetadata metadata = TiffDecoderMetadataCreator.Create(reader.ByteOrder, reader.IsBigTiff, rootFrameExifProfile);
             int width = GetImageWidth(rootFrameExifProfile);
             int height = GetImageHeight(rootFrameExifProfile);
 

src/ImageSharp/Formats/Tiff/TiffDecoderMetadataCreator.cs

@@ -18,7 +18,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
     /// </summary>
     internal static class TiffDecoderMetadataCreator
     {
-        public static ImageMetadata Create<TPixel>(List<ImageFrame<TPixel>> frames, bool ignoreMetadata, ByteOrder byteOrder)
+        public static ImageMetadata Create<TPixel>(List<ImageFrame<TPixel>> frames, bool ignoreMetadata, ByteOrder byteOrder, bool isBigTiff)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             if (frames.Count < 1)
@@ -26,13 +26,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
                 TiffThrowHelper.ThrowImageFormatException("Expected at least one frame.");
             }
 
-            var imageMetaData = new ImageMetadata();
-            ExifProfile exifProfileRootFrame = frames[0].Metadata.ExifProfile;
-
-            SetResolution(imageMetaData, exifProfileRootFrame);
-
-            TiffMetadata tiffMetadata = imageMetaData.GetTiffMetadata();
-            tiffMetadata.ByteOrder = byteOrder;
+            ImageMetadata imageMetaData = Create(byteOrder, isBigTiff, frames[0].Metadata.ExifProfile);
 
             if (!ignoreMetadata)
             {
@@ -56,13 +50,14 @@ namespace SixLabors.ImageSharp.Formats.Tiff
             return imageMetaData;
         }
 
-        public static ImageMetadata Create(ByteOrder byteOrder, ExifProfile exifProfile)
+        public static ImageMetadata Create(ByteOrder byteOrder, bool isBigTiff, ExifProfile exifProfile)
         {
             var imageMetaData = new ImageMetadata();
             SetResolution(imageMetaData, exifProfile);
 
             TiffMetadata tiffMetadata = imageMetaData.GetTiffMetadata();
             tiffMetadata.ByteOrder = byteOrder;
+            tiffMetadata.IsBigTiff = isBigTiff;
 
             return imageMetaData;
         }

src/ImageSharp/Formats/Tiff/TiffMetadata.cs

@@ -26,6 +26,14 @@ namespace SixLabors.ImageSharp.Formats.Tiff
         /// </summary>
         public ByteOrder ByteOrder { get; set; }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether this instance is BigTiff format.
+        /// </summary>
+        /// <value>
+        ///   <c>true</c> if this instance BigTiff format; otherwise, <c>false</c>.
+        /// </value>
+        public bool IsBigTiff { get; set; }
+
         /// <inheritdoc/>
         public IDeepCloneable DeepClone() => new TiffMetadata(this);
     }