ImageSharp/tests/ImageSharp.Tests/Formats/WebP/PredictorEncoderTests.cs

// Copyright (c) Six Labors.
// Licensed under the Apache License, Version 2.0.

using System;
using System.IO;
using SixLabors.ImageSharp.Formats.Webp;
using SixLabors.ImageSharp.Formats.Webp.Lossless;
using SixLabors.ImageSharp.PixelFormats;
#if SUPPORTS_RUNTIME_INTRINSICS
using SixLabors.ImageSharp.Tests.TestUtilities;
#endif
using Xunit;

namespace SixLabors.ImageSharp.Tests.Formats.Webp
{
    [Trait("Format", "Webp")]
    public class PredictorEncoderTests
    {
        [Fact]
        public static void ColorSpaceTransform_WithBikeImage_ProducesExpectedData()
            => RunColorSpaceTransformTestWithBikeImage();

        [Fact]
        public static void ColorSpaceTransform_WithPeakImage_ProducesExpectedData()
            => RunColorSpaceTransformTestWithPeakImage();

#if SUPPORTS_RUNTIME_INTRINSICS
        [Fact]
        public void ColorSpaceTransform_WithPeakImage_WithHardwareIntrinsics_Works()
            => FeatureTestRunner.RunWithHwIntrinsicsFeature(ColorSpaceTransform_WithPeakImage_ProducesExpectedData, HwIntrinsics.AllowAll);

        [Fact]
        public void ColorSpaceTransform_WithPeakImage_WithoutSSE41_Works()
            => FeatureTestRunner.RunWithHwIntrinsicsFeature(ColorSpaceTransform_WithPeakImage_ProducesExpectedData, HwIntrinsics.DisableSSE41);

        [Fact]
        public void ColorSpaceTransform_WithBikeImage_WithHardwareIntrinsics_Works()
            => FeatureTestRunner.RunWithHwIntrinsicsFeature(ColorSpaceTransform_WithBikeImage_ProducesExpectedData, HwIntrinsics.AllowAll);

        [Fact]
        public void ColorSpaceTransform_WithBikeImage_WithoutSSE41_Works()
            => FeatureTestRunner.RunWithHwIntrinsicsFeature(ColorSpaceTransform_WithBikeImage_ProducesExpectedData, HwIntrinsics.DisableSSE41);
#endif

        private static void RunColorSpaceTransformTestWithPeakImage()
        {
            // arrange
            uint[] expectedData =
            {
                4278191104, 4278191104, 4278191104, 4278191104, 4278191104, 4278191104, 4278191104, 4294577152,
                4294707200, 4294707200, 4294707200, 4294707200, 4294837248, 4294837248, 4293926912, 4294316544,
                4278191104, 4278191104, 4294837248, 4294837248, 4280287232, 4280350720, 4294447104, 4294707200,
                4294838272, 4278516736, 4294837248, 4294837248, 4278516736, 4294707200, 4279298048, 4294837248,
                4294837248, 4294837248, 4294837248, 4280287232, 4280287232, 4292670464, 4279633408, 4294838272,
                4294837248, 4278516736, 4278516736, 4278516736, 4278516736, 4278516736, 4278778880, 4278193152,
                4278191104, 4280287232, 4280287232, 4280287232, 4280287232, 4293971968, 4280612864, 4292802560,
                4294837760, 4278516736, 4278516736, 4294837760, 4294707712, 4278516736, 4294837248, 4278193152,
                4280287232, 4278984704, 4280287232, 4278243328, 4280287232, 4278244352, 4280287232, 4280025088,
                4280025088, 4294837760, 4278192128, 4294838784, 4294837760, 4294707712, 4278778880, 4278324224,
                4280287232, 4280287232, 4278202368, 4279115776, 4280287232, 4278243328, 4280287232, 4280287232,
                4280025088, 4280287232, 4278192128, 4294838272, 4294838272, 4294837760, 4278190592, 4278778880,
                4280875008, 4280287232, 4279896576, 4281075712, 4281075712, 4280287232, 4280287232, 4280287232,
                4280287232, 4280287232, 4278190592, 4294709248, 4278516736, 4278516736, 4278584832, 4278909440,
                4280287232, 4280287232, 4294367744, 4294621184, 4279115776, 4280287232, 4280287232, 4280351744,
                4280287232, 4280287232, 4280287232, 4278513664, 4278516736, 4278716416, 4278584832, 4280291328,
                4293062144, 4280287232, 4280287232, 4280287232, 4294456320, 4280291328, 4280287232, 4280287232,
                4280287232, 4280287232, 4280287232, 4280287232, 4278513152, 4278716416, 4278584832, 4280291328,
                4278198272, 4278198272, 4278589952, 4278198272, 4278198272, 4280287232, 4278765568, 4280287232,
                4280287232, 4280287232, 4280287232, 4294712832, 4278513152, 4278716640, 4279300608, 4278584832,
                4280156672, 4279373312, 4278589952, 4279373312, 4278328832, 4278328832, 4278328832, 4279634432,
                4280287232, 4280287232, 4280287232, 4280287232, 4278457344, 4280483328, 4278584832, 4278385664,
                4279634432, 4279373312, 4279634432, 4280287232, 4280287232, 4280156672, 4278589952, 4278328832,
                4278198272, 4280156672, 4280483328, 4294363648, 4280287232, 4278376448, 4280287232, 4278647808,
                4280287232, 4280287232, 4279373312, 4280287232, 4280287232, 4280156672, 4280287232, 4278198272,
                4278198272, 4280156672, 4280287232, 4280287232, 4293669888, 4278765568, 4278765568, 4280287232,
                4280287232, 4280287232, 4279634432, 4279634432, 4280287232, 4280287232, 4280287232, 4280287232,
                4280287232, 4280287232, 4280287232, 4280287232, 4279373312, 4279764992, 4293539328, 4279896576,
                4280287232, 4280287232, 4280287232, 4279634432, 4278198272, 4279634432, 4280287232, 4280287232,
                4280287232, 4280287232, 4280287232, 4280287232, 4280287232, 4279503872, 4279503872, 4280288256,
                4280287232, 4280287232, 4280287232, 4280287232, 4280287232, 4280287232, 4280287232, 4280287232,
                4280287232, 4280287232, 4280287232, 4280287232, 4280287232, 4280287232, 4280287232, 4280287232
            };

            // Convert image pixels to bgra array.
            byte[] imgBytes = File.ReadAllBytes(TestImageFullPath(TestImages.Webp.Peak));
            using var image = Image.Load<Rgba32>(imgBytes);
            uint[] bgra = ToBgra(image);

            int colorTransformBits = 3;
            int transformWidth = LosslessUtils.SubSampleSize(image.Width, colorTransformBits);
            int transformHeight = LosslessUtils.SubSampleSize(image.Height, colorTransformBits);
            uint[] transformData = new uint[transformWidth * transformHeight];
            int[] scratch = new int[256];

            // act
            PredictorEncoder.ColorSpaceTransform(image.Width, image.Height, colorTransformBits, 75, bgra, transformData, scratch);

            // assert
            Assert.Equal(expectedData, transformData);
        }

        private static void RunColorSpaceTransformTestWithBikeImage()
        {
            // arrange
            uint[] expectedData =
            {
                4278714368, 4278192876, 4278198304, 4278198304, 4278190304, 4278190080, 4278190080, 4278198272,
                4278197760, 4278198816, 4278197794, 4278197774, 4278190080, 4278190080, 4278198816, 4278197281,
                4278197280, 4278197792, 4278200353, 4278191343, 4278190304, 4294713873, 4278198784, 4294844416,
                4278201578, 4278200044, 4278191343, 4278190288, 4294705200, 4294717139, 4278203628, 4278201064,
                4278201586, 4278197792, 4279240909
            };

            // Convert image pixels to bgra array.
            byte[] imgBytes = File.ReadAllBytes(TestImageFullPath(TestImages.Webp.Lossy.BikeSmall));
            using var image = Image.Load<Rgba32>(imgBytes, new WebpDecoder());
            uint[] bgra = ToBgra(image);

            int colorTransformBits = 4;
            int transformWidth = LosslessUtils.SubSampleSize(image.Width, colorTransformBits);
            int transformHeight = LosslessUtils.SubSampleSize(image.Height, colorTransformBits);
            uint[] transformData = new uint[transformWidth * transformHeight];
            int[] scratch = new int[256];

            // act
            PredictorEncoder.ColorSpaceTransform(image.Width, image.Height, colorTransformBits, 75, bgra, transformData, scratch);

            // assert
            Assert.Equal(expectedData, transformData);
        }

        private static uint[] ToBgra<TPixel>(Image<TPixel> image)
            where TPixel : unmanaged, IPixel<TPixel>
        {
            uint[] bgra = new uint[image.Width * image.Height];
            int idx = 0;
            for (int y = 0; y < image.Height; y++)
            {
                Span<TPixel> rowSpan = image.GetPixelRowSpan(y);
                for (int x = 0; x < rowSpan.Length; x++)
                {
                    bgra[idx++] = ToBgra32(rowSpan[x]).PackedValue;
                }
            }

            return bgra;
        }

        private static Bgra32 ToBgra32<TPixel>(TPixel color)
            where TPixel : unmanaged, IPixel<TPixel>
        {
            Rgba32 rgba = default;
            color.ToRgba32(ref rgba);
            var bgra = new Bgra32(rgba.R, rgba.G, rgba.B, rgba.A);
            return bgra;
        }

        private static string TestImageFullPath(string path)
            => Path.Combine(TestEnvironment.InputImagesDirectoryFullPath, path);
    }
}