Merge pull request #3096 from SixLabors/bp/openExr

Add support for OpenEXR image format

Author: JimBobSquarePants

ImageSharp.sln

@@ -37,8 +37,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{815C0625-CD3
 	ProjectSection(SolutionItems) = preProject
 		src\Directory.Build.props = src\Directory.Build.props
 		src\Directory.Build.targets = src\Directory.Build.targets
-		src\README.md = src\README.md
 		src\ImageSharp.ruleset = src\ImageSharp.ruleset
+		src\README.md = src\README.md
 	EndProjectSection
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ImageSharp", "src\ImageSharp\ImageSharp.csproj", "{2AA31A1F-142C-43F4-8687-09ABCA4B3A26}"
@@ -215,6 +215,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "issues", "issues", "{5C9B68
 	ProjectSection(SolutionItems) = preProject
 		tests\Images\Input\Jpg\issues\issue-1076-invalid-subsampling.jpg = tests\Images\Input\Jpg\issues\issue-1076-invalid-subsampling.jpg
 		tests\Images\Input\Jpg\issues\issue-1221-identify-multi-frame.jpg = tests\Images\Input\Jpg\issues\issue-1221-identify-multi-frame.jpg
+		tests\Images\Input\Jpg\issues\issue-2067-comment.jpg = tests\Images\Input\Jpg\issues\issue-2067-comment.jpg
 		tests\Images\Input\Jpg\issues\issue1006-incorrect-resize.jpg = tests\Images\Input\Jpg\issues\issue1006-incorrect-resize.jpg
 		tests\Images\Input\Jpg\issues\issue1049-exif-resize.jpg = tests\Images\Input\Jpg\issues\issue1049-exif-resize.jpg
 		tests\Images\Input\Jpg\issues\Issue159-MissingFF00-Progressive-Bedroom.jpg = tests\Images\Input\Jpg\issues\Issue159-MissingFF00-Progressive-Bedroom.jpg
@@ -238,7 +239,6 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "issues", "issues", "{5C9B68
 		tests\Images\Input\Jpg\issues\issue750-exif-tranform.jpg = tests\Images\Input\Jpg\issues\issue750-exif-tranform.jpg
 		tests\Images\Input\Jpg\issues\Issue845-Incorrect-Quality99.jpg = tests\Images\Input\Jpg\issues\Issue845-Incorrect-Quality99.jpg
 		tests\Images\Input\Jpg\issues\issue855-incorrect-colorspace.jpg = tests\Images\Input\Jpg\issues\issue855-incorrect-colorspace.jpg
-		tests\Images\Input\Jpg\issues\issue-2067-comment.jpg = tests\Images\Input\Jpg\issues\issue-2067-comment.jpg
 	EndProjectSection
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "fuzz", "fuzz", "{516A3532-6AC2-417B-AD79-9BD5D0D378A0}"

src/ImageSharp/Common/Helpers/ColorNumerics.cs

@@ -97,7 +97,7 @@ public static ushort Get16BitBT709Luminance(float r, float g, float b)
     /// Scales a value from a 16 bit <see cref="ushort"/> to an
     /// 8 bit <see cref="byte"/> equivalent.
     /// </summary>
-    /// <param name="component">The 8 bit component value.</param>
+    /// <param name="component">The 16 bit component value.</param>
     /// <returns>The <see cref="byte"/></returns>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static byte From16BitTo8Bit(ushort component) =>
@@ -132,6 +132,49 @@ public static byte From16BitTo8Bit(ushort component) =>
         //    (V * 255 + 32895) >> 16
         (byte)(((component * 255) + 32895) >> 16);
 
+    /// <summary>
+    /// Scales a value from a 32 bit <see cref="uint"/> to an
+    /// 8 bit <see cref="byte"/> equivalent.
+    /// </summary>
+    /// <param name="component">The 32 bit component value.</param>
+    /// <returns>The <see cref="byte"/> value.</returns>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static byte From32BitTo8Bit(uint component) =>
+
+        // To scale to 8 bits from a 32-bit value V the required value is:
+        //
+        //    (V * 255) / 4294967295
+        //
+        // Since:
+        //
+        //    4294967295 = 255 * 16843009
+        //
+        // this reduces exactly to:
+        //
+        //    V / 16843009
+        //
+        // To round to nearest using integer arithmetic we add half the divisor
+        // before dividing:
+        //
+        //    (V + 16843009 / 2) / 16843009
+        //
+        // where:
+        //
+        //    16843009 / 2 = 8421504.5
+        //
+        // Using 8421504 ensures correct round-to-nearest behaviour:
+        //
+        //    8421504 -> 0
+        //    8421505 -> 1
+        //
+        // The addition must be performed in 64-bit to avoid overflow for large
+        // input values (for example uint.MaxValue).
+        //
+        // Final exact integer implementation:
+        //
+        //    ((ulong)V + 8421504) / 16843009
+        (byte)((component + 8421504UL) / 16843009UL);
+
     /// <summary>
     /// Scales a value from an 8 bit <see cref="byte"/> to
     /// an 16 bit <see cref="ushort"/> equivalent.
@@ -142,6 +185,26 @@ public static byte From16BitTo8Bit(ushort component) =>
     public static ushort From8BitTo16Bit(byte component)
         => (ushort)(component * 257);
 
+    /// <summary>
+    /// Scales a value from an 16 bit <see cref="byte"/> to
+    /// an 16 bit <see cref="uint"/> equivalent.
+    /// </summary>
+    /// <param name="component">The 16 bit component value.</param>
+    /// <returns>The 32 bit <see cref="uint"/></returns>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint From16BitTo32Bit(ushort component)
+        => (uint)(component * 65537);
+
+    /// <summary>
+    /// Scales a value from an 8 bit <see cref="byte"/> to
+    /// an 32 bit <see cref="ushort"/> equivalent.
+    /// </summary>
+    /// <param name="component">The 8 bit component value.</param>
+    /// <returns>The 32 bit <see cref="uint"/></returns>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint From8BitTo32Bit(byte component)
+        => (uint)(component * 16843009);
+
     /// <summary>
     /// Returns how many bits are required to store the specified number of colors.
     /// Performs a Log2() on the value.

src/ImageSharp/Configuration.cs

@@ -5,6 +5,7 @@
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Bmp;
 using SixLabors.ImageSharp.Formats.Cur;
+using SixLabors.ImageSharp.Formats.Exr;
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Formats.Ico;
 using SixLabors.ImageSharp.Formats.Jpeg;
@@ -213,6 +214,7 @@ public void Configure(IImageFormatConfigurationModule configuration)
     /// <see cref="TgaConfigurationModule"/>.
     /// <see cref="TiffConfigurationModule"/>.
     /// <see cref="WebpConfigurationModule"/>.
+    /// <see cref="ExrConfigurationModule"/>.
     /// <see cref="QoiConfigurationModule"/>.
     /// </summary>
     /// <returns>The default configuration of <see cref="Configuration"/>.</returns>
@@ -225,6 +227,7 @@ public void Configure(IImageFormatConfigurationModule configuration)
             new TgaConfigurationModule(),
             new TiffConfigurationModule(),
             new WebpConfigurationModule(),
+            new ExrConfigurationModule(),
             new QoiConfigurationModule(),
             new IcoConfigurationModule(),
             new CurConfigurationModule());

src/ImageSharp/Formats/Bmp/BmpConstants.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
 namespace SixLabors.ImageSharp.Formats.Bmp;

src/ImageSharp/Formats/Bmp/BmpFormat.cs

@@ -30,5 +30,5 @@ private BmpFormat()
     public IEnumerable<string> FileExtensions => BmpConstants.FileExtensions;
 
     /// <inheritdoc/>
-    public BmpMetadata CreateDefaultFormatMetadata() => new();
+    public BmpMetadata CreateDefaultFormatMetadata() => new BmpMetadata();
 }

src/ImageSharp/Formats/Exr/Compression/Compressors/NoneExrCompressor.cs

@@ -0,0 +1,36 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Memory;
+
+namespace SixLabors.ImageSharp.Formats.Exr.Compression.Compressors;
+
+/// <summary>
+/// Compressor for EXR image data which does not use any compression method.
+/// </summary>
+internal class NoneExrCompressor : ExrBaseCompressor
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="NoneExrCompressor"/> class.
+    /// </summary>
+    /// <param name="output">The output stream to write the compressed image data to.</param>
+    /// <param name="allocator">The memory allocator.</param>
+    /// <param name="bytesPerBlock">Bytes per row block.</param>
+    /// <param name="bytesPerRow">Bytes per pixel row.</param>
+    public NoneExrCompressor(Stream output, MemoryAllocator allocator, uint bytesPerBlock, uint bytesPerRow)
+        : base(output, allocator, bytesPerBlock, bytesPerRow)
+    {
+    }
+
+    /// <inheritdoc/>
+    public override uint CompressRowBlock(Span<byte> rows, int rowCount)
+    {
+        this.Output.Write(rows);
+        return (uint)rows.Length;
+    }
+
+    /// <inheritdoc/>
+    protected override void Dispose(bool disposing)
+    {
+    }
+}

src/ImageSharp/Formats/Exr/Compression/Compressors/ZipExrCompressor.cs

@@ -0,0 +1,84 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Compression.Zlib;
+using SixLabors.ImageSharp.Memory;
+
+namespace SixLabors.ImageSharp.Formats.Exr.Compression.Compressors;
+
+/// <summary>
+/// Compressor for EXR image data using the ZIP compression.
+/// </summary>
+internal class ZipExrCompressor : ExrBaseCompressor
+{
+    private readonly DeflateCompressionLevel compressionLevel;
+
+    private readonly MemoryStream memoryStream;
+
+    private readonly System.Buffers.IMemoryOwner<byte> buffer;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ZipExrCompressor"/> class.
+    /// </summary>
+    /// <param name="output">The stream to write the compressed data to.</param>
+    /// <param name="allocator">The memory allocator.</param>
+    /// <param name="bytesPerBlock">The bytes per block.</param>
+    /// <param name="bytesPerRow">The bytes per row.</param>
+    /// <param name="compressionLevel">The compression level for deflate compression.</param>
+    public ZipExrCompressor(Stream output, MemoryAllocator allocator, uint bytesPerBlock, uint bytesPerRow, DeflateCompressionLevel compressionLevel)
+        : base(output, allocator, bytesPerBlock, bytesPerRow)
+    {
+        this.compressionLevel = compressionLevel;
+        this.buffer = allocator.Allocate<byte>((int)bytesPerBlock);
+        this.memoryStream = new();
+    }
+
+    /// <inheritdoc/>
+    public override uint CompressRowBlock(Span<byte> rows, int rowCount)
+    {
+        // Re-oder pixel values.
+        Span<byte> reordered = this.buffer.GetSpan()[..(int)(rowCount * this.BytesPerRow)];
+        int n = reordered.Length;
+        int t1 = 0;
+        int t2 = (n + 1) >> 1;
+        for (int i = 0; i < n; i++)
+        {
+            bool isOdd = (i & 1) == 1;
+            reordered[isOdd ? t2++ : t1++] = rows[i];
+        }
+
+        // Predictor.
+        Span<byte> predicted = reordered;
+        byte p = predicted[0];
+        for (int i = 1; i < predicted.Length; i++)
+        {
+            int d = (predicted[i] - p + 128 + 256) & 255;
+            p = predicted[i];
+            predicted[i] = (byte)d;
+        }
+
+        this.memoryStream.Seek(0, SeekOrigin.Begin);
+        using (ZlibDeflateStream stream = new(this.Allocator, this.memoryStream, this.compressionLevel))
+        {
+            stream.Write(predicted);
+            stream.Flush();
+        }
+
+        int size = (int)this.memoryStream.Position;
+        byte[] buffer = this.memoryStream.GetBuffer();
+        this.Output.Write(buffer, 0, size);
+
+        // Reset memory stream for next pixel row.
+        this.memoryStream.Seek(0, SeekOrigin.Begin);
+        this.memoryStream.SetLength(0);
+
+        return (uint)size;
+    }
+
+    /// <inheritdoc/>
+    protected override void Dispose(bool disposing)
+    {
+        this.buffer.Dispose();
+        this.memoryStream?.Dispose();
+    }
+}