Write EXIF chunk, if Exif profile is present

src/ImageSharp/Formats/WebP/BitWriter/BitWriterBase.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Buffers.Binary;
 using System.IO;
+using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 
 namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
 {
@@ -55,7 +56,10 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
         /// Writes the encoded image to the stream.
         /// </summary>
         /// <param name="stream">The stream to write to.</param>
-        public abstract void WriteEncodedImageToStream(Stream stream);
+        /// <param name="exifProfile">The exif profile.</param>
+        /// <param name="width">The width of the image.</param>
+        /// <param name="height">The height of the image.</param>
+        public abstract void WriteEncodedImageToStream(Stream stream, ExifProfile exifProfile, uint width, uint height);
 
         protected bool ResizeBuffer(int maxBytes, int sizeRequired)
         {
@@ -84,12 +88,68 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
         /// <param name="riffSize">The block length.</param>
         protected void WriteRiffHeader(Stream stream, uint riffSize)
         {
-            Span<byte> buffer = stackalloc byte[4];
-
+            Span<byte> buf = stackalloc byte[4];
             stream.Write(WebpConstants.RiffFourCc);
-            BinaryPrimitives.WriteUInt32LittleEndian(buffer, riffSize);
-            stream.Write(buffer);
+            BinaryPrimitives.WriteUInt32LittleEndian(buf, riffSize);
+            stream.Write(buf);
             stream.Write(WebpConstants.WebPHeader);
         }
+
+        /// <summary>
+        /// Writes the Exif profile to the stream.
+        /// </summary>
+        /// <param name="stream">The stream to write to.</param>
+        /// <param name="exifBytes">The exif profile bytes.</param>
+        protected void WriteExifProfile(Stream stream, byte[] exifBytes)
+        {
+            DebugGuard.NotNull(exifBytes, nameof(exifBytes));
+
+            Span<byte> buf = stackalloc byte[4];
+            BinaryPrimitives.WriteUInt32BigEndian(buf, (uint)WebpChunkType.Exif);
+            stream.Write(buf);
+            BinaryPrimitives.WriteUInt32LittleEndian(buf, (uint)exifBytes.Length);
+            stream.Write(buf);
+            stream.Write(exifBytes);
+        }
+
+        /// <summary>
+        /// Writes a VP8X header to the stream.
+        /// </summary>
+        /// <param name="stream">The stream to write to.</param>
+        /// <param name="exifProfile">A exif profile or null, if it does not exist.</param>
+        /// <param name="width">The width of the image.</param>
+        /// <param name="height">The height of the image.</param>
+        protected void WriteVp8XHeader(Stream stream, ExifProfile exifProfile, uint width, uint height)
+        {
+            int maxDimension = 16777215;
+            if (width > maxDimension || height > maxDimension)
+            {
+                WebpThrowHelper.ThrowInvalidImageDimensions($"Image width or height exceeds maximum allowed dimension of {maxDimension}");
+            }
+
+            // The spec states that the product of Canvas Width and Canvas Height MUST be at most 2^32 - 1.
+            if (width * height > 4294967295ul)
+            {
+                WebpThrowHelper.ThrowInvalidImageDimensions("The product of image width and height MUST be at most 2^32 - 1");
+            }
+
+            uint flags = 0;
+            if (exifProfile != null)
+            {
+                // Set exif bit.
+                flags |= 8;
+            }
+
+            Span<byte> buf = stackalloc byte[4];
+            stream.Write(WebpConstants.Vp8XMagicBytes);
+            BinaryPrimitives.WriteUInt32LittleEndian(buf, WebpConstants.Vp8XChunkSize);
+            stream.Write(buf);
+            BinaryPrimitives.WriteUInt32LittleEndian(buf, flags);
+            stream.Write(buf);
+            BinaryPrimitives.WriteUInt32LittleEndian(buf, width - 1);
+            stream.Write(buf.Slice(0, 3));
+            BinaryPrimitives.WriteUInt32LittleEndian(buf, height - 1);
+            stream.Write(buf.Slice(0, 3));
+        }
     }
 }

src/ImageSharp/Formats/WebP/BitWriter/Vp8BitWriter.cs

@@ -5,6 +5,7 @@ using System;
 using System.Buffers.Binary;
 using System.IO;
 using SixLabors.ImageSharp.Formats.Experimental.Webp.Lossy;
+using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 
 namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
 {
@@ -73,16 +74,10 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
         /// <param name="expectedSize">The expected size in bytes.</param>
         /// <param name="enc">The Vp8Encoder.</param>
         public Vp8BitWriter(int expectedSize, Vp8Encoder enc)
-            : this(expectedSize)
-        {
-            this.enc = enc;
-        }
+            : this(expectedSize) => this.enc = enc;
 
         /// <inheritdoc/>
-        public override int NumBytes()
-        {
-            return (int)this.pos;
-        }
+        public override int NumBytes() => (int)this.pos;
 
         public int PutCoeffs(int ctx, Vp8Residual residual)
         {
@@ -290,10 +285,7 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
             }
         }
 
-        private bool PutBit(bool bit, int prob)
-        {
-            return this.PutBit(bit ? 1 : 0, prob);
-        }
+        private bool PutBit(bool bit, int prob) => this.PutBit(bit ? 1 : 0, prob);
 
         private bool PutBit(int bit, int prob)
         {
@@ -408,8 +400,19 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
         }
 
         /// <inheritdoc/>
-        public override void WriteEncodedImageToStream(Stream stream)
+        public override void WriteEncodedImageToStream(Stream stream, ExifProfile exifProfile, uint width, uint height)
         {
+            bool isVp8X = false;
+            byte[] exifBytes = null;
+            uint riffSize = 0;
+            if (exifProfile != null)
+            {
+                isVp8X = true;
+                riffSize += WebpConstants.ChunkHeaderSize + WebpConstants.Vp8XChunkSize;
+                exifBytes = exifProfile.ToByteArray();
+                riffSize += WebpConstants.ChunkHeaderSize + (uint)exifBytes.Length;
+            }
+
             this.Finish();
             uint numBytes = (uint)this.NumBytes();
             int mbSize = this.enc.Mbw * this.enc.Mbh;
@@ -427,10 +430,10 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
 
             // Compute RIFF size
             // At the minimum it is: "WEBPVP8 nnnn" + VP8 data size.
-            var riffSize = WebpConstants.TagSize + WebpConstants.ChunkHeaderSize + vp8Size;
+            riffSize += WebpConstants.TagSize + WebpConstants.ChunkHeaderSize + vp8Size;
 
             // Emit headers and partition #0
-            this.WriteWebPHeaders(stream, size0, vp8Size, riffSize);
+            this.WriteWebpHeaders(stream, size0, vp8Size, riffSize, isVp8X, width, height, exifProfile);
             bitWriterPartZero.WriteToStream(stream);
 
             // Write the encoded image to the stream.
@@ -439,6 +442,11 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
             {
                 stream.WriteByte(0);
             }
+
+            if (exifProfile != null)
+            {
+                this.WriteExifProfile(stream, exifBytes);
+            }
         }
 
         private uint GeneratePartition0(Vp8BitWriter bitWriter)
@@ -608,9 +616,16 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
             while (it.Next());
         }
 
-        private void WriteWebPHeaders(Stream stream, uint size0, uint vp8Size, uint riffSize)
+        private void WriteWebpHeaders(Stream stream, uint size0, uint vp8Size, uint riffSize, bool isVp8X, uint width, uint height, ExifProfile exifProfile)
         {
             this.WriteRiffHeader(stream, riffSize);
+
+            // Write VP8X, header if necessary.
+            if (isVp8X)
+            {
+                this.WriteVp8XHeader(stream, exifProfile, width, height);
+            }
+
             this.WriteVp8Header(stream, vp8Size);
             this.WriteFrameHeader(stream, size0);
         }

src/ImageSharp/Formats/WebP/BitWriter/Vp8LBitWriter.cs

@@ -5,6 +5,7 @@ using System;
 using System.Buffers.Binary;
 using System.IO;
 using SixLabors.ImageSharp.Formats.Experimental.Webp.Lossless;
+using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 
 namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
 {
@@ -127,9 +128,19 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
         }
 
         /// <inheritdoc/>
-        public override void WriteEncodedImageToStream(Stream stream)
+        public override void WriteEncodedImageToStream(Stream stream, ExifProfile exifProfile, uint width, uint height)
         {
             Span<byte> buffer = stackalloc byte[4];
+            bool isVp8X = false;
+            byte[] exifBytes = null;
+            uint riffSize = 0;
+            if (exifProfile != null)
+            {
+                isVp8X = true;
+                riffSize += WebpConstants.ChunkHeaderSize + WebpConstants.Vp8XChunkSize;
+                exifBytes = exifProfile.ToByteArray();
+                riffSize += WebpConstants.ChunkHeaderSize + (uint)exifBytes.Length;
+            }
 
             this.Finish();
             uint size = (uint)this.NumBytes();
@@ -137,8 +148,16 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
 
             // Write RIFF header.
             uint pad = size & 1;
-            uint riffSize = WebpConstants.TagSize + WebpConstants.ChunkHeaderSize + size + pad;
+            riffSize += WebpConstants.TagSize + WebpConstants.ChunkHeaderSize + size + pad;
             this.WriteRiffHeader(stream, riffSize);
+
+            // Write VP8X, header if necessary.
+            if (isVp8X)
+            {
+                this.WriteVp8XHeader(stream, exifProfile, width, height);
+            }
+
+            // Write magic bytes indicating its a lossless webp.
             stream.Write(WebpConstants.Vp8LMagicBytes);
 
             // Write Vp8 Header.
@@ -146,11 +165,17 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.BitWriter
             stream.Write(buffer);
             stream.WriteByte(WebpConstants.Vp8LHeaderMagicByte);
 
+            // Write the encoded bytes of the image to the stream.
             this.WriteToStream(stream);
             if (pad == 1)
             {
                 stream.WriteByte(0);
             }
+
+            if (exifProfile != null)
+            {
+                this.WriteExifProfile(stream, exifBytes);
+            }
         }
 
         /// <summary>

src/ImageSharp/Formats/WebP/Lossless/Vp8LEncoder.cs

@@ -185,7 +185,7 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.Lossless
             this.EncodeStream(image);
 
             // Write bytes from the bitwriter buffer to the stream.
-            this.bitWriter.WriteEncodedImageToStream(stream);
+            this.bitWriter.WriteEncodedImageToStream(stream, image.Metadata.ExifProfile, (uint)width, (uint)height);
         }
 
         /// <summary>

src/ImageSharp/Formats/WebP/Lossy/Vp8Encoder.cs

@@ -321,7 +321,7 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp.Lossy
             this.AdjustFilterStrength();
 
             // Write bytes from the bitwriter buffer to the stream.
-            this.bitWriter.WriteEncodedImageToStream(stream);
+            this.bitWriter.WriteEncodedImageToStream(stream, image.Metadata.ExifProfile, (uint)width, (uint)height);
         }
 
         /// <inheritdoc/>

src/ImageSharp/Formats/WebP/WebpConstants.cs

@@ -57,6 +57,17 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp
             0x4C // L
         };
 
+        /// <summary>
+        /// Signature bytes identifying a VP8X header.
+        /// </summary>
+        public static readonly byte[] Vp8XMagicBytes =
+        {
+            0x56, // V
+            0x50, // P
+            0x38, // 8
+            0x58 // X
+        };
+
         /// <summary>
         /// The header bytes identifying RIFF file.
         /// </summary>
@@ -94,6 +105,11 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp
         /// </summary>
         public const int Vp8FrameHeaderSize = 10;
 
+        /// <summary>
+        /// Size of a VP8X chunk in bytes.
+        /// </summary>
+        public const int Vp8XChunkSize = 10;
+
         /// <summary>
         /// Size of a chunk header.
         /// </summary>

src/ImageSharp/Formats/WebP/WebpDecoderCore.cs

@@ -84,7 +84,7 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp
             this.Metadata = new ImageMetadata();
             this.currentStream = stream;
 
-            this.ReadImageHeader();
+            var fileSize = this.ReadImageHeader();
 
             using (this.webImageInfo = this.ReadVp8Info())
             {
@@ -131,7 +131,7 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp
         /// <summary>
         /// Reads and skips over the image header.
         /// </summary>
-        /// <returns>The chunk size in bytes.</returns>
+        /// <returns>The file size in bytes.</returns>
         private uint ReadImageHeader()
         {
             // Skip FourCC header, we already know its a RIFF file at this point.
@@ -140,12 +140,12 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp
             // Read file size.
             // The size of the file in bytes starting at offset 8.
             // The file size in the header is the total size of the chunks that follow plus 4 bytes for the ‘WEBP’ FourCC.
-            uint chunkSize = this.ReadChunkSize();
+            uint fileSize = this.ReadChunkSize();
 
             // Skip 'WEBP' from the header.
             this.currentStream.Skip(4);
 
-            return chunkSize;
+            return fileSize;
         }
 
         /// <summary>
@@ -185,7 +185,7 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp
         private WebpImageInfo ReadVp8XHeader()
         {
             var features = new WebpFeatures();
-            uint chunkSize = this.ReadChunkSize();
+            uint fileSize = this.ReadChunkSize();
 
             // The first byte contains information about the image features used.
             byte imageFeatures = (byte)this.currentStream.ReadByte();
@@ -474,7 +474,7 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp
                 WebpChunkType chunkType = this.ReadChunkType();
                 uint chunkLength = this.ReadChunkSize();
 
-                if (chunkType == WebpChunkType.Exif)
+                if (chunkType == WebpChunkType.Exif && this.Metadata.ExifProfile == null)
                 {
                     var exifData = new byte[chunkLength];
                     this.currentStream.Read(exifData, 0, (int)chunkLength);
@@ -482,7 +482,7 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp
                 }
                 else
                 {
-                    // Skip XMP chunk data for now.
+                    // Skip XMP chunk data or any duplicate EXIF chunk.
                     this.currentStream.Skip((int)chunkLength);
                 }
             }

src/ImageSharp/Formats/WebP/WebpThrowHelper.cs

@@ -13,19 +13,20 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Webp
         /// </summary>
         /// <param name="errorMessage">The error message for the exception.</param>
         [MethodImpl(MethodImplOptions.NoInlining)]
-        public static void ThrowImageFormatException(string errorMessage)
-        {
-            throw new ImageFormatException(errorMessage);
-        }
+        public static void ThrowImageFormatException(string errorMessage) => throw new ImageFormatException(errorMessage);
 
         /// <summary>
         /// Cold path optimization for throwing <see cref="NotSupportedException"/>-s
         /// </summary>
         /// <param name="errorMessage">The error message for the exception.</param>
         [MethodImpl(MethodImplOptions.NoInlining)]
-        public static void ThrowNotSupportedException(string errorMessage)
-        {
-            throw new NotSupportedException(errorMessage);
-        }
+        public static void ThrowNotSupportedException(string errorMessage) => throw new NotSupportedException(errorMessage);
+
+        /// <summary>
+        /// Cold path optimization for throwing <see cref="InvalidImageContentException"/>-s
+        /// </summary>
+        /// <param name="errorMessage">The error message for the exception.</param>
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        public static void ThrowInvalidImageDimensions(string errorMessage) => throw new InvalidImageContentException(errorMessage);
     }
 }