ImageSharp/tests/ImageSharp.Tests/Formats/Png/PngSmokeTests.cs

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

using System.IO;
using SixLabors.ImageSharp.Formats.Png;
using SixLabors.ImageSharp.PixelFormats;
using SixLabors.ImageSharp.Processing;
using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
using Xunit;

namespace SixLabors.ImageSharp.Tests.Formats.Png
{
    [Trait("Format", "Png")]
    public class PngSmokeTests
    {
        [Theory]
        [WithTestPatternImages(300, 300, PixelTypes.Rgba32)]
        public void GeneralTest<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : unmanaged, IPixel<TPixel>
        {
            // does saving a file then reopening mean both files are identical???
            using (Image<TPixel> image = provider.GetImage())
            using (var ms = new MemoryStream())
            {
                // image.Save(provider.Utility.GetTestOutputFileName("bmp"));
                image.Save(ms, new PngEncoder());
                ms.Position = 0;
                using (var img2 = Image.Load<Rgba32>(ms, new PngDecoder()))
                {
                    ImageComparer.Tolerant().VerifySimilarity(image, img2);

                    // img2.Save(provider.Utility.GetTestOutputFileName("bmp", "_loaded"), new BmpEncoder());
                }
            }
        }

        /* JJS: Disabled for now as the decoder now correctly decodes the full pixel components if the
         paletted image has alpha of 0
        [Theory]
        [WithTestPatternImages(100, 100, PixelTypes.Rgba32)]
        public void CanSaveIndexedPng<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : unmanaged, IPixel<TPixel>
        {
            // does saving a file then reopening mean both files are identical???
            using (Image<TPixel> image = provider.GetImage())
            using (MemoryStream ms = new MemoryStream())
            {
                // image.Save(provider.Utility.GetTestOutputFileName("bmp"));
                image.Save(ms, new PngEncoder() { PaletteSize = 256 });
                ms.Position = 0;
                using (Image<Rgba32> img2 = Image.Load<Rgba32>(ms, new PngDecoder()))
                {
                    ImageComparer.VerifySimilarity(image, img2, 0.03f);
                }
            }
        }*/

        /* JJS: Commented out for now since the test does not take into lossy nature of indexing.
        [Theory]
        [WithTestPatternImages(100, 100, PixelTypes.Color)]
        public void CanSaveIndexedPngTwice<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : unmanaged, IPixel<TPixel>
        {
            // does saving a file then reopening mean both files are identical???
            using (Image<TPixel> source = provider.GetImage())
            using (MemoryStream ms = new MemoryStream())
            {
                source.Metadata.Quality = 256;
                source.Save(ms, new PngEncoder(), new PngEncoderOptions {
                    Threshold = 200
                });
                ms.Position = 0;
                using (Image img1 = Image.Load(ms, new PngDecoder()))
                {
                    using (MemoryStream ms2 = new MemoryStream())
                    {
                        img1.Save(ms2, new PngEncoder(), new PngEncoderOptions
                        {
                            Threshold = 200
                        });
                        ms2.Position = 0;
                        using (Image img2 = Image.Load(ms2, new PngDecoder()))
                        {
                            using (PixelAccessor<Color> pixels1 = img1.Lock())
                            using (PixelAccessor<Color> pixels2 = img2.Lock())
                            {
                                for (int y = 0; y < img1.Height; y++)
                                {
                                    for (int x = 0; x < img1.Width; x++)
                                    {
                                        Assert.Equal(pixels1[x, y], pixels2[x, y]);
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }*/

        [Theory]
        [WithTestPatternImages(300, 300, PixelTypes.Rgba32)]
        public void Resize<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : unmanaged, IPixel<TPixel>
        {
            // does saving a file then reopening mean both files are identical???
            using (Image<TPixel> image = provider.GetImage())
            using (var ms = new MemoryStream())
            {
                // image.Save(provider.Utility.GetTestOutputFileName("png"));
                image.Mutate(x => x.Resize(100, 100));

                // image.Save(provider.Utility.GetTestOutputFileName("png", "resize"));
                image.Save(ms, new PngEncoder());
                ms.Position = 0;
                using (var img2 = Image.Load<Rgba32>(ms, new PngDecoder()))
                {
                    ImageComparer.Tolerant().VerifySimilarity(image, img2);
                }
            }
        }
    }
}