Adding QOI support

.gitattributes

@@ -118,6 +118,7 @@
 *.bmp               filter=lfs diff=lfs merge=lfs -text
 *.gif               filter=lfs diff=lfs merge=lfs -text
 *.png               filter=lfs diff=lfs merge=lfs -text
+*.qoi               filter=lfs diff=lfs merge=lfs -text
 *.tif               filter=lfs diff=lfs merge=lfs -text
 *.tiff              filter=lfs diff=lfs merge=lfs -text
 *.tga               filter=lfs diff=lfs merge=lfs -text

ImageSharp.sln

@@ -646,6 +646,18 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Tga", "Tga", "{5DFC394F-136
 		tests\Images\Input\Tga\targa_8bit_rle.tga = tests\Images\Input\Tga\targa_8bit_rle.tga
 	EndProjectSection
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Qoi", "Qoi", "{E801B508-4935-41CD-BA85-CF11BFF55A45}"
+	ProjectSection(SolutionItems) = preProject
+		tests\Images\Input\Qoi\dice.qoi = tests\Images\Input\Qoi\dice.qoi
+		tests\Images\Input\Qoi\edgecase.qoi = tests\Images\Input\Qoi\edgecase.qoi
+		tests\Images\Input\Qoi\kodim10.qoi = tests\Images\Input\Qoi\kodim10.qoi
+		tests\Images\Input\Qoi\kodim23.qoi = tests\Images\Input\Qoi\kodim23.qoi
+		tests\Images\Input\Qoi\qoi_logo.qoi = tests\Images\Input\Qoi\qoi_logo.qoi
+		tests\Images\Input\Qoi\testcard.qoi = tests\Images\Input\Qoi\testcard.qoi
+		tests\Images\Input\Qoi\testcard_rgba.qoi = tests\Images\Input\Qoi\testcard_rgba.qoi
+		tests\Images\Input\Qoi\wikipedia_008.qoi = tests\Images\Input\Qoi\wikipedia_008.qoi
+	EndProjectSection
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -698,6 +710,7 @@ Global
 		{FC527290-2F22-432C-B77B-6E815726B02C} = {56801022-D71A-4FBE-BC5B-CBA08E2284EC}
 		{670DD46C-82E9-499A-B2D2-00A802ED0141} = {E1C42A6F-913B-4A7B-B1A8-2BB62843B254}
 		{5DFC394F-136F-4B76-9BCA-3BA786515EFC} = {9DA226A1-8656-49A8-A58A-A8B5C081AD66}
+		{E801B508-4935-41CD-BA85-CF11BFF55A45} = {9DA226A1-8656-49A8-A58A-A8B5C081AD66}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {5F8B9D1F-CD8B-4CC5-8216-D531E25BD795}

src/ImageSharp/Common/Helpers/Numerics.cs

@@ -73,6 +73,30 @@ public static int LeastCommonMultiple(int a, int b)
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static nint Modulo8(nint x) => x & 7;
 
+    /// <summary>
+    /// Calculates <paramref name="x"/> % 64
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static int Modulo64(int x) => x & 63;
+
+    /// <summary>
+    /// Calculates <paramref name="x"/> % 64
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static nint Modulo64(nint x) => x & 63;
+
+    /// <summary>
+    /// Calculates <paramref name="x"/> % 256
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static int Modulo256(int x) => x & 255;
+
+    /// <summary>
+    /// Calculates <paramref name="x"/> % 256
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static nint Modulo256(nint x) => x & 255;
+
     /// <summary>
     /// Fast (x mod m) calculator, with the restriction that
     /// <paramref name="m"/> should be power of 2.

src/ImageSharp/Configuration.cs

@@ -8,6 +8,7 @@
 using SixLabors.ImageSharp.Formats.Jpeg;
 using SixLabors.ImageSharp.Formats.Pbm;
 using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.Formats.Qoi;
 using SixLabors.ImageSharp.Formats.Tga;
 using SixLabors.ImageSharp.Formats.Tiff;
 using SixLabors.ImageSharp.Formats.Webp;
@@ -212,6 +213,7 @@ public void Configure(IImageFormatConfigurationModule configuration)
     /// <see cref="TgaConfigurationModule"/>.
     /// <see cref="TiffConfigurationModule"/>.
     /// <see cref="WebpConfigurationModule"/>.
+    /// <see cref="QoiConfigurationModule"/>.
     /// </summary>
     /// <returns>The default configuration of <see cref="Configuration"/>.</returns>
     internal static Configuration CreateDefaultInstance() => new(
@@ -222,5 +224,6 @@ public void Configure(IImageFormatConfigurationModule configuration)
             new PbmConfigurationModule(),
             new TgaConfigurationModule(),
             new TiffConfigurationModule(),
-            new WebpConfigurationModule());
+            new WebpConfigurationModule(),
+            new QoiConfigurationModule());
 }

src/ImageSharp/Formats/ImageExtensions.Save.cs

@@ -9,6 +9,7 @@
 using SixLabors.ImageSharp.Formats.Jpeg;
 using SixLabors.ImageSharp.Formats.Pbm;
 using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.Formats.Qoi;
 using SixLabors.ImageSharp.Formats.Tga;
 using SixLabors.ImageSharp.Formats.Webp;
 using SixLabors.ImageSharp.Formats.Tiff;
@@ -836,4 +837,105 @@ public static Task SaveAsTiffAsync(this Image source, Stream stream, TiffEncoder
               encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(TiffFormat.Instance),
               cancellationToken);
 
+    /// <summary>
+    /// Saves the image to the given stream with the Qoi format.
+    /// </summary>
+    /// <param name="source">The image this method extends.</param>
+    /// <param name="path">The file path to save the image to.</param>
+    /// <exception cref="System.ArgumentNullException">Thrown if the path is null.</exception>
+    public static void SaveAsQoi(this Image source, string path) => SaveAsQoi(source, path, default);
+
+    /// <summary>
+    /// Saves the image to the given stream with the Qoi format.
+    /// </summary>
+    /// <param name="source">The image this method extends.</param>
+    /// <param name="path">The file path to save the image to.</param>
+    /// <exception cref="System.ArgumentNullException">Thrown if the path is null.</exception>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    public static Task SaveAsQoiAsync(this Image source, string path) => SaveAsQoiAsync(source, path, default);
+
+    /// <summary>
+    /// Saves the image to the given stream with the Qoi format.
+    /// </summary>
+    /// <param name="source">The image this method extends.</param>
+    /// <param name="path">The file path to save the image to.</param>
+    /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
+    /// <exception cref="System.ArgumentNullException">Thrown if the path is null.</exception>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    public static Task SaveAsQoiAsync(this Image source, string path, CancellationToken cancellationToken)
+        => SaveAsQoiAsync(source, path, default, cancellationToken);
+
+    /// <summary>
+    /// Saves the image to the given stream with the Qoi format.
+    /// </summary>
+    /// <param name="source">The image this method extends.</param>
+    /// <param name="path">The file path to save the image to.</param>
+    /// <param name="encoder">The encoder to save the image with.</param>
+    /// <exception cref="System.ArgumentNullException">Thrown if the path is null.</exception>
+    public static void SaveAsQoi(this Image source, string path, QoiEncoder encoder) =>
+        source.Save(
+            path,
+            encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(QoiFormat.Instance));
+
+    /// <summary>
+    /// Saves the image to the given stream with the Qoi format.
+    /// </summary>
+    /// <param name="source">The image this method extends.</param>
+    /// <param name="path">The file path to save the image to.</param>
+    /// <param name="encoder">The encoder to save the image with.</param>
+    /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
+    /// <exception cref="System.ArgumentNullException">Thrown if the path is null.</exception>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    public static Task SaveAsQoiAsync(this Image source, string path, QoiEncoder encoder, CancellationToken cancellationToken = default)
+        => source.SaveAsync(
+              path,
+              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(QoiFormat.Instance),
+              cancellationToken);
+
+    /// <summary>
+    /// Saves the image to the given stream with the Qoi format.
+    /// </summary>
+    /// <param name="source">The image this method extends.</param>
+    /// <param name="stream">The stream to save the image to.</param>
+    /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+    public static void SaveAsQoi(this Image source, Stream stream)
+        => SaveAsQoi(source, stream, default);
+
+    /// <summary>
+    /// Saves the image to the given stream with the Qoi format.
+    /// </summary>
+    /// <param name="source">The image this method extends.</param>
+    /// <param name="stream">The stream to save the image to.</param>
+    /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
+    /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    public static Task SaveAsQoiAsync(this Image source, Stream stream, CancellationToken cancellationToken = default)
+        => SaveAsQoiAsync(source, stream, default, cancellationToken);
+
+    /// <summary>
+    /// Saves the image to the given stream with the Qoi format.
+    /// </summary>
+    /// <param name="source">The image this method extends.</param>
+    /// <param name="stream">The stream to save the image to.</param>
+    /// <param name="encoder">The encoder to save the image with.</param>
+    /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+    public static void SaveAsQoi(this Image source, Stream stream, QoiEncoder encoder)
+        => source.Save(
+              stream,
+              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(QoiFormat.Instance));
+
+    /// <summary>
+    /// Saves the image to the given stream with the Qoi format.
+    /// </summary>
+    /// <param name="source">The image this method extends.</param>
+    /// <param name="stream">The stream to save the image to.</param>
+    /// <param name="encoder">The encoder to save the image with.</param>
+    /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
+    /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    public static Task SaveAsQoiAsync(this Image source, Stream stream, QoiEncoder encoder, CancellationToken cancellationToken = default)
+        => source.SaveAsync(
+              stream,
+              encoder ?? source.GetConfiguration().ImageFormatsManager.GetEncoder(QoiFormat.Instance),
+              cancellationToken);
 }

src/ImageSharp/Formats/Qoi/MetadataExtensions.cs

@@ -0,0 +1,20 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Formats.Qoi;
+using SixLabors.ImageSharp.Metadata;
+
+namespace SixLabors.ImageSharp;
+
+/// <summary>
+/// Extension methods for the <see cref="ImageMetadata"/> type.
+/// </summary>
+public static partial class MetadataExtensions
+{
+    /// <summary>
+    /// Gets the qoi format specific metadata for the image.
+    /// </summary>
+    /// <param name="metadata">The metadata this method extends.</param>
+    /// <returns>The <see cref="QoiMetadata"/>.</returns>
+    public static QoiMetadata GetQoiMetadata(this ImageMetadata metadata) => metadata.GetFormatMetadata(QoiFormat.Instance);
+}

src/ImageSharp/Formats/Qoi/QoiChannels.cs

@@ -0,0 +1,20 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Formats.Qoi;
+
+/// <summary>
+/// Provides enumeration of available QOI color channels.
+/// </summary>
+public enum QoiChannels
+{
+    /// <summary>
+    /// Each pixel is an R,G,B triple.
+    /// </summary>
+    Rgb = 3,
+
+    /// <summary>
+    /// Each pixel is an R,G,B triple, followed by an alpha sample.
+    /// </summary>
+    Rgba = 4
+}

src/ImageSharp/Formats/Qoi/QoiChunk.cs

@@ -0,0 +1,56 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Formats.Qoi;
+
+/// <summary>
+/// Enum that contains the operations that encoder and decoder must process, written
+/// in binary to be easier to compare them in the reference
+/// </summary>
+internal enum QoiChunk
+{
+    /// <summary>
+    /// Indicates that the operation is QOI_OP_RGB where the RGB values are written
+    /// in one byte each one after this marker
+    /// </summary>
+    QoiOpRgb = 0b11111110,
+
+    /// <summary>
+    /// Indicates that the operation is QOI_OP_RGBA where the RGBA values are written
+    /// in one byte each one after this marker
+    /// </summary>
+    QoiOpRgba = 0b11111111,
+
+    /// <summary>
+    /// Indicates that the operation is QOI_OP_INDEX where one byte contains a 2-bit
+    /// marker (0b00) followed by an index on the previously seen pixels array 0..63
+    /// </summary>
+    QoiOpIndex = 0b00000000,
+
+    /// <summary>
+    /// Indicates that the operation is QOI_OP_DIFF where one byte contains a 2-bit
+    /// marker (0b01) followed by 2-bit differences in red, green and blue channel
+    /// with the previous pixel with a bias of 2 (-2..1)
+    /// </summary>
+    QoiOpDiff = 0b01000000,
+
+    /// <summary>
+    /// Indicates that the operation is QOI_OP_LUMA where one byte contains a 2-bit
+    /// marker (0b01) followed by a 6-bits number that indicates the difference of
+    /// the green channel with the previous pixel. Then another byte that contains
+    /// a 4-bit number that indicates the difference of the red channel minus the
+    /// previous difference, and another 4-bit number that indicates the difference
+    /// of the blue channel minus the green difference
+    /// Example: 0b10[6-bits diff green] 0b[6-bits dr-dg][6-bits db-dg]
+    /// dr_dg = (cur_px.r - prev_px.r) - (cur_px.g - prev_px.g)
+    /// db_dg = (cur_px.b - prev_px.b) - (cur_px.g - prev_px.g)
+    /// </summary>
+    QoiOpLuma = 0b10000000,
+
+    /// <summary>
+    /// Indicates that the operation is QOI_OP_RUN where one byte contains a 2-bit
+    /// marker (0b11) followed by a 6-bits number that indicates the times that the
+    /// previous pixel is repeated
+    /// </summary>
+    QoiOpRun = 0b11000000
+}

src/ImageSharp/Formats/Qoi/QoiColorSpace.cs

@@ -0,0 +1,22 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+// ReSharper disable InconsistentNaming
+// ReSharper disable IdentifierTypo
+namespace SixLabors.ImageSharp.Formats.Qoi;
+
+/// <summary>
+/// Enum for the different QOI color spaces.
+/// </summary>
+public enum QoiColorSpace
+{
+    /// <summary>
+    /// sRGB color space with linear alpha value
+    /// </summary>
+    SrgbWithLinearAlpha,
+
+    /// <summary>
+    /// All the values in the color space are linear
+    /// </summary>
+    AllChannelsLinear
+}

src/ImageSharp/Formats/Qoi/QoiConfigurationModule.cs

@@ -0,0 +1,18 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Formats.Qoi;
+
+/// <summary>
+/// Registers the image encoders, decoders and mime type detectors for the qoi format.
+/// </summary>
+public sealed class QoiConfigurationModule : IImageFormatConfigurationModule
+{
+    /// <inheritdoc/>
+    public void Configure(Configuration configuration)
+    {
+        configuration.ImageFormatsManager.SetDecoder(QoiFormat.Instance, QoiDecoder.Instance);
+        configuration.ImageFormatsManager.SetEncoder(QoiFormat.Instance, new QoiEncoder());
+        configuration.ImageFormatsManager.AddImageFormatDetector(new QoiImageFormatDetector());
+    }
+}

src/ImageSharp/Formats/Qoi/QoiConstants.cs

@@ -0,0 +1,27 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using System.Text;
+
+namespace SixLabors.ImageSharp.Formats.Qoi;
+
+internal static class QoiConstants
+{
+    private static readonly byte[] SMagic = Encoding.UTF8.GetBytes("qoif");
+
+    /// <summary>
+    /// Gets the bytes that indicates the image is QOI
+    /// </summary>
+    public static ReadOnlySpan<byte> Magic => SMagic;
+
+    /// <summary>
+    /// Gets the list of mimetypes that equate to a QOI.
+    /// See https://github.com/phoboslab/qoi/issues/167
+    /// </summary>
+    public static string[] MimeTypes { get; } = { "image/qoi", "image/x-qoi", "image/vnd.qoi" };
+
+    /// <summary>
+    /// Gets the list of file extensions that equate to a QOI.
+    /// </summary>
+    public static string[] FileExtensions { get; } = { "qoi" };
+}