ImageSharp/tests/ImageSharp.Tests/Formats/Jpg/JpegEncoderTests.cs

// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

using SixLabors.ImageSharp.Formats.Jpeg;
using SixLabors.ImageSharp.PixelFormats;
using SixLabors.ImageSharp.Tests.TestUtilities;
using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;

namespace SixLabors.ImageSharp.Tests.Formats.Jpg;

[Trait("Format", "Jpg")]
public partial class JpegEncoderTests
{
    private static JpegEncoder JpegEncoder => new();

    private static readonly TheoryData<int> TestQualities = new()
    {
        40,
        80,
        100,
    };

    public static readonly TheoryData<JpegEncodingColor, int, float> NonSubsampledEncodingSetups = new()
    {
        { JpegEncodingColor.Rgb, 100, 0.0238f / 100 },
        { JpegEncodingColor.Rgb, 80,  1.3044f / 100 },
        { JpegEncodingColor.Rgb, 40,  2.9879f / 100 },
        { JpegEncodingColor.YCbCrRatio444, 100, 0.0780f / 100 },
        { JpegEncodingColor.YCbCrRatio444, 80,  1.4585f / 100 },
        { JpegEncodingColor.YCbCrRatio444, 40,  3.1413f / 100 },
    };

    public static readonly TheoryData<JpegEncodingColor, int, float> SubsampledEncodingSetups = new()
    {
        { JpegEncodingColor.YCbCrRatio422, 100, 0.4895f / 100 },
        { JpegEncodingColor.YCbCrRatio422, 80,  1.6043f / 100 },
        { JpegEncodingColor.YCbCrRatio422, 40,  3.1996f / 100 },
        { JpegEncodingColor.YCbCrRatio420, 100, 0.5790f / 100 },
        { JpegEncodingColor.YCbCrRatio420, 80,  1.6692f / 100 },
        { JpegEncodingColor.YCbCrRatio420, 40,  3.2324f / 100 },
        { JpegEncodingColor.YCbCrRatio411, 100, 0.6868f / 100 },
        { JpegEncodingColor.YCbCrRatio411, 80,  1.7139f / 100 },
        { JpegEncodingColor.YCbCrRatio411, 40,  3.2634f / 100 },
        { JpegEncodingColor.YCbCrRatio410, 100, 0.7357f / 100 },
        { JpegEncodingColor.YCbCrRatio410, 80,  1.7495f / 100 },
        { JpegEncodingColor.YCbCrRatio410, 40,  3.2911f / 100 },
    };

    public static readonly TheoryData<JpegEncodingColor, int, float> CmykEncodingSetups = new()
    {
        { JpegEncodingColor.Cmyk, 100, 0.0159f / 100 },
        { JpegEncodingColor.Cmyk, 80,  0.3922f / 100 },
        { JpegEncodingColor.Cmyk, 40,  0.6488f / 100 },
    };

    public static readonly TheoryData<JpegEncodingColor, int, float> YcckEncodingSetups = new()
    {
        { JpegEncodingColor.Ycck, 100, 0.0356f / 100 },
        { JpegEncodingColor.Ycck, 80,  0.1245f / 100 },
        { JpegEncodingColor.Ycck, 40,  0.2663f / 100 },
    };

    public static readonly TheoryData<JpegEncodingColor, int, float> LuminanceEncodingSetups = new()
    {
        { JpegEncodingColor.Luminance, 100, 0.0175f / 100 },
        { JpegEncodingColor.Luminance, 80,  0.6730f / 100 },
        { JpegEncodingColor.Luminance, 40,  0.9941f / 100 },
    };

    [Theory]
    [WithFile(TestImages.Png.CalliphoraPartial, nameof(NonSubsampledEncodingSetups), PixelTypes.Rgb24)]
    [WithFile(TestImages.Png.CalliphoraPartial, nameof(SubsampledEncodingSetups), PixelTypes.Rgb24)]
    [WithFile(TestImages.Png.BikeGrayscale, nameof(LuminanceEncodingSetups), PixelTypes.L8)]
    [WithFile(TestImages.Jpeg.Baseline.Cmyk, nameof(CmykEncodingSetups), PixelTypes.Rgb24)]
    [WithFile(TestImages.Jpeg.Baseline.Ycck, nameof(YcckEncodingSetups), PixelTypes.Rgb24)]
    public void EncodeBaseline_Interleaved<TPixel>(TestImageProvider<TPixel> provider, JpegEncodingColor colorType, int quality, float tolerance)
        where TPixel : unmanaged, IPixel<TPixel> => TestJpegEncoderCore(provider, colorType, quality, tolerance);

    [Theory]
    [WithFile(TestImages.Png.CalliphoraPartial, nameof(NonSubsampledEncodingSetups), PixelTypes.Rgb24)]
    [WithFile(TestImages.Png.CalliphoraPartial, nameof(SubsampledEncodingSetups), PixelTypes.Rgb24)]
    [WithFile(TestImages.Png.BikeGrayscale, nameof(LuminanceEncodingSetups), PixelTypes.L8)]
    [WithFile(TestImages.Jpeg.Baseline.Cmyk, nameof(CmykEncodingSetups), PixelTypes.Rgb24)]
    [WithFile(TestImages.Jpeg.Baseline.Ycck, nameof(YcckEncodingSetups), PixelTypes.Rgb24)]
    public void EncodeBaseline_NonInterleavedMode<TPixel>(TestImageProvider<TPixel> provider, JpegEncodingColor colorType, int quality, float tolerance)
        where TPixel : unmanaged, IPixel<TPixel>
    {
        using Image<TPixel> image = provider.GetImage();

        var encoder = new JpegEncoder
        {
            Quality = quality,
            ColorType = colorType,
            Interleaved = false,
        };
        string info = $"{colorType}-Q{quality}";

        ImageComparer comparer = new TolerantImageComparer(tolerance);

        // Does DebugSave & load reference CompareToReferenceInput():
        image.VerifyEncoder(provider, "jpeg", info, encoder, comparer, referenceImageExtension: "jpg");
    }

    [Theory]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 600, 400, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 158, 24, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 153, 21, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 143, 81, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 138, 24, PixelTypes.Rgb24)]
    public void EncodeBaseline_WorksWithDifferentSizes<TPixel>(TestImageProvider<TPixel> provider, JpegEncodingColor colorType, int quality, float tolerance)
        where TPixel : unmanaged, IPixel<TPixel> => TestJpegEncoderCore(provider, colorType, quality);

    [Theory]
    [WithSolidFilledImages(nameof(NonSubsampledEncodingSetups), 1, 1, 100, 100, 100, 255, PixelTypes.L8)]
    [WithSolidFilledImages(nameof(NonSubsampledEncodingSetups), 1, 1, 255, 100, 50, 255, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 143, 81, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 7, 5, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 96, 48, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 73, 71, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 48, 24, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 46, 8, PixelTypes.Rgb24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 51, 7, PixelTypes.Rgb24)]
    public void EncodeBaseline_WithSmallImages_WorksWithDifferentSizes<TPixel>(TestImageProvider<TPixel> provider, JpegEncodingColor colorType, int quality, float tolerance)
        where TPixel : unmanaged, IPixel<TPixel> => TestJpegEncoderCore(provider, colorType, quality, ImageComparer.Tolerant(0.12f));

    [Theory]
    [WithSolidFilledImages(1, 1, 100, 100, 100, 255, PixelTypes.Rgb24, 100)]
    [WithSolidFilledImages(1, 1, 100, 100, 100, 255, PixelTypes.L8, 100)]
    [WithSolidFilledImages(1, 1, 100, 100, 100, 255, PixelTypes.L16, 100)]
    [WithSolidFilledImages(1, 1, 100, 100, 100, 255, PixelTypes.La16, 100)]
    [WithSolidFilledImages(1, 1, 100, 100, 100, 255, PixelTypes.La32, 100)]
    public void EncodeBaseline_Grayscale<TPixel>(TestImageProvider<TPixel> provider, int quality)
        where TPixel : unmanaged, IPixel<TPixel> => TestJpegEncoderCore(provider, JpegEncodingColor.Luminance, quality);

    [Theory]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 96, 96, PixelTypes.Rgb24 | PixelTypes.Bgr24)]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 48, 48, PixelTypes.Rgb24 | PixelTypes.Bgr24)]
    public void EncodeBaseline_IsNotBoundToSinglePixelType<TPixel>(TestImageProvider<TPixel> provider, JpegEncodingColor colorType, int quality, float tolerance)
        where TPixel : unmanaged, IPixel<TPixel> => TestJpegEncoderCore(provider, colorType, quality);

    [Theory]
    [WithTestPatternImages(nameof(NonSubsampledEncodingSetups), 48, 48, PixelTypes.Rgb24 | PixelTypes.Bgr24)]
    public void EncodeBaseline_WithSmallImages_IsNotBoundToSinglePixelType<TPixel>(TestImageProvider<TPixel> provider, JpegEncodingColor colorType, int quality, float tolerance)
        where TPixel : unmanaged, IPixel<TPixel> => TestJpegEncoderCore(provider, colorType, quality, comparer: ImageComparer.Tolerant(0.06f));

    [Theory]
    [WithFile(TestImages.Png.CalliphoraPartial, PixelTypes.Rgb24, JpegEncodingColor.YCbCrRatio444)]
    [WithTestPatternImages(587, 821, PixelTypes.Rgb24, JpegEncodingColor.YCbCrRatio444)]
    [WithTestPatternImages(677, 683, PixelTypes.Rgb24, JpegEncodingColor.YCbCrRatio420)]
    [WithSolidFilledImages(400, 400, nameof(Color.Red), PixelTypes.Rgb24, JpegEncodingColor.YCbCrRatio420)]
    public void EncodeBaseline_WorksWithDiscontiguousBuffers<TPixel>(TestImageProvider<TPixel> provider, JpegEncodingColor colorType)
        where TPixel : unmanaged, IPixel<TPixel>
    {
        ImageComparer comparer = colorType == JpegEncodingColor.YCbCrRatio444
            ? ImageComparer.TolerantPercentage(0.1f)
            : ImageComparer.TolerantPercentage(5f);

        provider.LimitAllocatorBufferCapacity().InBytesSqrt(200);
        TestJpegEncoderCore(provider, colorType, 100, comparer);
    }

    [Theory]
    [InlineData(JpegEncodingColor.YCbCrRatio420)]
    [InlineData(JpegEncodingColor.YCbCrRatio444)]
    public async Task Encode_IsCancellable(JpegEncodingColor colorType)
    {
        var cts = new CancellationTokenSource();
        using var pausedStream = new PausedStream(new MemoryStream());
        pausedStream.OnWaiting(s =>
        {
            // after some writing
            if (s.Position >= 500)
            {
                cts.Cancel();
                pausedStream.Release();
            }
            else
            {
                // allows this/next wait to unblock
                pausedStream.Next();
            }
        });

        using var image = new Image<Rgba32>(5000, 5000);
        await Assert.ThrowsAsync<TaskCanceledException>(async () =>
        {
            var encoder = new JpegEncoder() { ColorType = colorType };
            await image.SaveAsync(pausedStream, encoder, cts.Token);
        });
    }

    /// <summary>
    /// Anton's SUPER-SCIENTIFIC tolerance threshold calculation
    /// </summary>
    private static ImageComparer GetComparer(int quality, JpegEncodingColor? colorType)
    {
        float tolerance = 0.015f; // ~1.5%

        if (quality < 50)
        {
            tolerance *= 4.5f;
        }
        else if (quality < 75 || colorType == JpegEncodingColor.YCbCrRatio420)
        {
            tolerance *= 2.0f;
            if (colorType == JpegEncodingColor.YCbCrRatio420)
            {
                tolerance *= 2.0f;
            }
        }

        return ImageComparer.Tolerant(tolerance);
    }

    private static void TestJpegEncoderCore<TPixel>(TestImageProvider<TPixel> provider, JpegEncodingColor colorType, int quality)
        where TPixel : unmanaged, IPixel<TPixel>
        => TestJpegEncoderCore(provider, colorType, quality, GetComparer(quality, colorType));

    private static void TestJpegEncoderCore<TPixel>(TestImageProvider<TPixel> provider, JpegEncodingColor colorType, int quality, float tolerance)
        where TPixel : unmanaged, IPixel<TPixel>
        => TestJpegEncoderCore(provider, colorType, quality, new TolerantImageComparer(tolerance));

    private static void TestJpegEncoderCore<TPixel>(TestImageProvider<TPixel> provider, JpegEncodingColor colorType, int quality, ImageComparer comparer)
        where TPixel : unmanaged, IPixel<TPixel>
    {
        using Image<TPixel> image = provider.GetImage();

        var encoder = new JpegEncoder
        {
            Quality = quality,
            ColorType = colorType
        };
        string info = $"{colorType}-Q{quality}";

        // Does DebugSave & load reference CompareToReferenceInput():
        image.VerifyEncoder(provider, "jpeg", info, encoder, comparer, referenceImageExtension: "png");
    }
}