ImageSharp/tests/ImageSharp.Tests/Processing/Transforms/ProjectiveTransformTests.cs

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

using System.Numerics;
using System.Reflection;
using SixLabors.ImageSharp.PixelFormats;
using SixLabors.ImageSharp.Processing;
using SixLabors.ImageSharp.Processing.Processors.Transforms;
using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
using Xunit.Abstractions;

// ReSharper disable InconsistentNaming
namespace SixLabors.ImageSharp.Tests.Processing.Transforms;

[Trait("Category", "Processors")]
public class ProjectiveTransformTests
{
    private static readonly ImageComparer ValidatorComparer = ImageComparer.TolerantPercentage(0.03f, 3);
    private static readonly ImageComparer TolerantComparer = ImageComparer.TolerantPercentage(0.5f, 3);

    private ITestOutputHelper Output { get; }

    public static readonly TheoryData<string> ResamplerNames = new TheoryData<string>
    {
        nameof(KnownResamplers.Bicubic),
        nameof(KnownResamplers.Box),
        nameof(KnownResamplers.CatmullRom),
        nameof(KnownResamplers.Hermite),
        nameof(KnownResamplers.Lanczos2),
        nameof(KnownResamplers.Lanczos3),
        nameof(KnownResamplers.Lanczos5),
        nameof(KnownResamplers.Lanczos8),
        nameof(KnownResamplers.MitchellNetravali),
        nameof(KnownResamplers.NearestNeighbor),
        nameof(KnownResamplers.Robidoux),
        nameof(KnownResamplers.RobidouxSharp),
        nameof(KnownResamplers.Spline),
        nameof(KnownResamplers.Triangle),
        nameof(KnownResamplers.Welch),
    };

    public static readonly TheoryData<TaperSide, TaperCorner> TaperMatrixData = new TheoryData<TaperSide, TaperCorner>
    {
        { TaperSide.Bottom, TaperCorner.Both },
        { TaperSide.Bottom, TaperCorner.LeftOrTop },
        { TaperSide.Bottom, TaperCorner.RightOrBottom },
        { TaperSide.Top, TaperCorner.Both },
        { TaperSide.Top, TaperCorner.LeftOrTop },
        { TaperSide.Top, TaperCorner.RightOrBottom },
        { TaperSide.Left, TaperCorner.Both },
        { TaperSide.Left, TaperCorner.LeftOrTop },
        { TaperSide.Left, TaperCorner.RightOrBottom },
        { TaperSide.Right, TaperCorner.Both },
        { TaperSide.Right, TaperCorner.LeftOrTop },
        { TaperSide.Right, TaperCorner.RightOrBottom },
    };

    public ProjectiveTransformTests(ITestOutputHelper output) => this.Output = output;

    [Theory]
    [WithTestPatternImages(nameof(ResamplerNames), 150, 150, PixelTypes.Rgba32)]
    public void Transform_WithSampler<TPixel>(TestImageProvider<TPixel> provider, string resamplerName)
        where TPixel : unmanaged, IPixel<TPixel>
    {
        IResampler sampler = GetResampler(resamplerName);
        using (Image<TPixel> image = provider.GetImage())
        {
            ProjectiveTransformBuilder builder = new ProjectiveTransformBuilder()
                .AppendTaper(TaperSide.Right, TaperCorner.Both, .5F);

            image.Mutate(i => i.Transform(builder, sampler));

            image.DebugSave(provider, resamplerName);
            image.CompareToReferenceOutput(ValidatorComparer, provider, resamplerName);
        }
    }

    [Theory]
    [WithSolidFilledImages(nameof(TaperMatrixData), 30, 30, nameof(Color.Red), PixelTypes.Rgba32)]
    public void Transform_WithTaperMatrix<TPixel>(TestImageProvider<TPixel> provider, TaperSide taperSide, TaperCorner taperCorner)
        where TPixel : unmanaged, IPixel<TPixel>
    {
        using (Image<TPixel> image = provider.GetImage())
        {
            ProjectiveTransformBuilder builder = new ProjectiveTransformBuilder()
                .AppendTaper(taperSide, taperCorner, .5F);

            image.Mutate(i => i.Transform(builder));

            FormattableString testOutputDetails = $"{taperSide}-{taperCorner}";
            image.DebugSave(provider, testOutputDetails);
            image.CompareFirstFrameToReferenceOutput(TolerantComparer, provider, testOutputDetails);
        }
    }

    [Theory]
    [WithSolidFilledImages(100, 100, 0, 0, 255, PixelTypes.Rgba32)]
    public void RawTransformMatchesDocumentedExample<TPixel>(TestImageProvider<TPixel> provider)
        where TPixel : unmanaged, IPixel<TPixel>
    {
        // Printing some extra output to help investigating rounding errors:
        this.Output.WriteLine($"Vector.IsHardwareAccelerated: {Vector.IsHardwareAccelerated}");

        // This test matches the output described in the example at
        // https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/graphics/skiasharp/transforms/non-affine
        using (Image<TPixel> image = provider.GetImage())
        {
            Matrix4x4 matrix = Matrix4x4.Identity;
            matrix.M14 = 0.01F;

            ProjectiveTransformBuilder builder = new ProjectiveTransformBuilder()
            .AppendMatrix(matrix);

            image.Mutate(i => i.Transform(builder));

            image.DebugSave(provider);
            image.CompareToReferenceOutput(TolerantComparer, provider);
        }
    }

    [Theory]
    [WithSolidFilledImages(290, 154, 0, 0, 255, PixelTypes.Rgba32)]
    public void PerspectiveTransformMatchesCSS<TPixel>(TestImageProvider<TPixel> provider)
        where TPixel : unmanaged, IPixel<TPixel>
    {
        // https://jsfiddle.net/dFrHS/545/
        // https://github.com/SixLabors/ImageSharp/issues/787
        using (Image<TPixel> image = provider.GetImage())
        {
#pragma warning disable SA1117 // Parameters should be on same line or separate lines
            var matrix = new Matrix4x4(
               0.260987f, -0.434909f, 0, -0.0022184f,
               0.373196f, 0.949882f, 0, -0.000312129f,
               0, 0, 1, 0,
               52, 165, 0, 1);
#pragma warning restore SA1117 // Parameters should be on same line or separate lines

            ProjectiveTransformBuilder builder = new ProjectiveTransformBuilder()
            .AppendMatrix(matrix);

            image.Mutate(i => i.Transform(builder));

            image.DebugSave(provider);
            image.CompareToReferenceOutput(TolerantComparer, provider);
        }
    }

    [Fact]
    public void Issue1911()
    {
        using var image = new Image<Rgba32>(100, 100);
        image.Mutate(x => x = x.Transform(new Rectangle(0, 0, 99, 100), Matrix4x4.Identity, new Size(99, 100), KnownResamplers.Lanczos2));

        Assert.Equal(99, image.Width);
        Assert.Equal(100, image.Height);
    }

    [Theory]
    [WithTestPatternImages(100, 100, PixelTypes.Rgba32)]
    public void Identity<TPixel>(TestImageProvider<TPixel> provider)
        where TPixel : unmanaged, IPixel<TPixel>
    {
        using Image<TPixel> image = provider.GetImage();

        Matrix4x4 m = Matrix4x4.Identity;
        Rectangle r = new(25, 25, 50, 50);
        image.Mutate(x => x.Transform(r, m, new Size(100, 100), KnownResamplers.Bicubic));
        image.DebugSave(provider);
        image.CompareToReferenceOutput(ValidatorComparer, provider);
    }

    [Theory]
    [WithTestPatternImages(100, 100, PixelTypes.Rgba32, 0.0001F)]
    [WithTestPatternImages(100, 100, PixelTypes.Rgba32, 57F)]
    [WithTestPatternImages(100, 100, PixelTypes.Rgba32, 0F)]
    public void Transform_With_Custom_Dimensions<TPixel>(TestImageProvider<TPixel> provider, float radians)
        where TPixel : unmanaged, IPixel<TPixel>
    {
        using Image<TPixel> image = provider.GetImage();

        Matrix4x4 m = Matrix4x4.CreateRotationX(radians, new Vector3(50, 50, 1F)) * Matrix4x4.CreateRotationY(radians, new Vector3(50, 50, 1F));
        Rectangle r = new(25, 25, 50, 50);
        image.Mutate(x => x.Transform(r, m, new Size(100, 100), KnownResamplers.Bicubic));
        image.DebugSave(provider, testOutputDetails: radians);
        image.CompareToReferenceOutput(ValidatorComparer, provider, testOutputDetails: radians);
    }

    private static IResampler GetResampler(string name)
    {
        PropertyInfo property = typeof(KnownResamplers).GetTypeInfo().GetProperty(name);

        if (property is null)
        {
            throw new Exception($"No resampler named {name}");
        }

        return (IResampler)property.GetValue(null);
    }
}