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

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

// ReSharper disable InconsistentNaming

using System.Buffers.Binary;
using System.IO;
using System.Text;

using SixLabors.ImageSharp.Formats.Png;
using SixLabors.ImageSharp.MetaData;
using SixLabors.ImageSharp.PixelFormats;
using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;

using Xunit;

namespace SixLabors.ImageSharp.Tests.Formats.Png
{
    public partial class PngDecoderTests
    {
        private const PixelTypes PixelTypes = Tests.PixelTypes.Rgba32 | Tests.PixelTypes.RgbaVector | Tests.PixelTypes.Argb32;

        public static readonly string[] CommonTestImages =
        {
            TestImages.Png.Splash,
            TestImages.Png.Indexed,
            TestImages.Png.FilterVar,
            TestImages.Png.Bad.ChunkLength1,
            TestImages.Png.Bad.CorruptedChunk,

            TestImages.Png.VimImage1,
            TestImages.Png.VersioningImage1,
            TestImages.Png.VersioningImage2,

            TestImages.Png.SnakeGame,
            TestImages.Png.Banner7Adam7InterlaceMode,
            TestImages.Png.Banner8Index,

            TestImages.Png.Bad.ChunkLength2,
            TestImages.Png.VimImage2,

            TestImages.Png.Rgb24BppTrans,
            TestImages.Png.GrayAlpha8Bit
        };

        public static readonly string[] TestImages48Bpp =
        {
            TestImages.Png.Rgb48Bpp,
            TestImages.Png.Rgb48BppInterlaced
        };

        public static readonly string[] TestImages64Bpp =
{
            TestImages.Png.Rgba64Bpp,
            TestImages.Png.Rgb48BppTrans
        };

        public static readonly string[] TestImagesGray16Bit =
        {
            TestImages.Png.Gray16Bit,
        };

        public static readonly string[] TestImagesGrayAlpha16Bit =
        {
            TestImages.Png.GrayAlpha16Bit,
            TestImages.Png.GrayTrns16BitInterlaced
        };

        public static readonly TheoryData<string, int, int, PixelResolutionUnit> RatioFiles =
        new TheoryData<string, int, int, PixelResolutionUnit>
        {
            { TestImages.Png.Splash, 11810, 11810 , PixelResolutionUnit.PixelsPerMeter},
            { TestImages.Png.Ratio1x4, 1, 4 , PixelResolutionUnit.AspectRatio},
            { TestImages.Png.Ratio4x1, 4, 1, PixelResolutionUnit.AspectRatio }
        };

        [Theory]
        [WithFileCollection(nameof(CommonTestImages), PixelTypes.Rgba32)]
        public void Decode<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : struct, IPixel<TPixel>
        {
            using (Image<TPixel> image = provider.GetImage(new PngDecoder()))
            {
                image.DebugSave(provider);
                image.CompareToOriginal(provider, ImageComparer.Exact);
            }
        }

        [Theory]
        [WithFile(TestImages.Png.Interlaced, PixelTypes.Rgba32)]
        public void Decode_Interlaced_ImageIsCorrect<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : struct, IPixel<TPixel>
        {
            using (Image<TPixel> image = provider.GetImage(new PngDecoder()))
            {
                image.DebugSave(provider);
                image.CompareToOriginal(provider, ImageComparer.Exact);
            }
        }

        [Theory]
        [WithFileCollection(nameof(TestImages48Bpp), PixelTypes.Rgb48)]
        public void Decode_48Bpp<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : struct, IPixel<TPixel>
        {
            using (Image<TPixel> image = provider.GetImage(new PngDecoder()))
            {
                image.DebugSave(provider);
                image.CompareToOriginal(provider, ImageComparer.Exact);
            }
        }

        [Theory]
        [WithFileCollection(nameof(TestImages64Bpp), PixelTypes.Rgba64)]
        public void Decode_64Bpp<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : struct, IPixel<TPixel>
        {
            using (Image<TPixel> image = provider.GetImage(new PngDecoder()))
            {
                image.DebugSave(provider);
                image.CompareToOriginal(provider, ImageComparer.Exact);
            }
        }

        [Theory]
        [WithFileCollection(nameof(TestImagesGray16Bit), PixelTypes.Rgb48)]
        public void Decode_Gray16Bit<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : struct, IPixel<TPixel>
        {
            using (Image<TPixel> image = provider.GetImage(new PngDecoder()))
            {
                image.DebugSave(provider);
                image.CompareToOriginal(provider, ImageComparer.Exact);
            }
        }

        [Theory]
        [WithFileCollection(nameof(TestImagesGrayAlpha16Bit), PixelTypes.Rgba64)]
        public void Decode_GrayAlpha16Bit<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : struct, IPixel<TPixel>
        {
            using (Image<TPixel> image = provider.GetImage(new PngDecoder()))
            {
                image.DebugSave(provider);
                image.CompareToOriginal(provider, ImageComparer.Exact);
            }
        }

        [Theory]
        [WithFile(TestImages.Png.Splash, PixelTypes)]
        public void Decoder_IsNotBoundToSinglePixelType<TPixel>(TestImageProvider<TPixel> provider)
            where TPixel : struct, IPixel<TPixel>
        {
            using (Image<TPixel> image = provider.GetImage(new PngDecoder()))
            {
                image.DebugSave(provider);
                image.CompareToOriginal(provider, ImageComparer.Exact);
            }
        }

        [Fact]
        public void Decode_IgnoreMetadataIsFalse_TextChunckIsRead()
        {
            var options = new PngDecoder()
            {
                IgnoreMetadata = false
            };

            var testFile = TestFile.Create(TestImages.Png.Blur);

            using (Image<Rgba32> image = testFile.CreateImage(options))
            {
                Assert.Equal(1, image.MetaData.Properties.Count);
                Assert.Equal("Software", image.MetaData.Properties[0].Name);
                Assert.Equal("paint.net 4.0.6", image.MetaData.Properties[0].Value);
            }
        }

        [Fact]
        public void Decode_IgnoreMetadataIsTrue_TextChunksAreIgnored()
        {
            var options = new PngDecoder()
            {
                IgnoreMetadata = true
            };

            var testFile = TestFile.Create(TestImages.Png.Blur);

            using (Image<Rgba32> image = testFile.CreateImage(options))
            {
                Assert.Equal(0, image.MetaData.Properties.Count);
            }
        }

        [Fact]
        public void Decode_TextEncodingSetToUnicode_TextIsReadWithCorrectEncoding()
        {
            var options = new PngDecoder()
            {
                TextEncoding = Encoding.Unicode
            };

            var testFile = TestFile.Create(TestImages.Png.Blur);

            using (Image<Rgba32> image = testFile.CreateImage(options))
            {
                Assert.Equal(1, image.MetaData.Properties.Count);
                Assert.Equal("潓瑦慷敲", image.MetaData.Properties[0].Name);
            }
        }

        [Theory]
        [InlineData(TestImages.Png.Bpp1, 1)]
        [InlineData(TestImages.Png.Gray4Bpp, 4)]
        [InlineData(TestImages.Png.Palette8Bpp, 8)]
        [InlineData(TestImages.Png.Pd, 24)]
        [InlineData(TestImages.Png.Blur, 32)]
        [InlineData(TestImages.Png.Rgb48Bpp, 48)]
        [InlineData(TestImages.Png.Rgb48BppInterlaced, 48)]
        public void Identify(string imagePath, int expectedPixelSize)
        {
            var testFile = TestFile.Create(imagePath);
            using (var stream = new MemoryStream(testFile.Bytes, false))
            {
                Assert.Equal(expectedPixelSize, Image.Identify(stream)?.PixelType?.BitsPerPixel);
            }
        }

        [Theory]
        [MemberData(nameof(RatioFiles))]
        public void Decode_VerifyRatio(string imagePath, int xResolution, int yResolution, PixelResolutionUnit resolutionUnit)
        {
            var testFile = TestFile.Create(imagePath);
            using (var stream = new MemoryStream(testFile.Bytes, false))
            {
                var decoder = new PngDecoder();
                using (Image<Rgba32> image = decoder.Decode<Rgba32>(Configuration.Default, stream))
                {
                    ImageMetaData meta = image.MetaData;
                    Assert.Equal(xResolution, meta.HorizontalResolution);
                    Assert.Equal(yResolution, meta.VerticalResolution);
                    Assert.Equal(resolutionUnit, meta.ResolutionUnits);
                }
            }
        }

        [Theory]
        [MemberData(nameof(RatioFiles))]
        public void Identify_VerifyRatio(string imagePath, int xResolution, int yResolution, PixelResolutionUnit resolutionUnit)
        {
            var testFile = TestFile.Create(imagePath);
            using (var stream = new MemoryStream(testFile.Bytes, false))
            {
                var decoder = new PngDecoder();
                IImageInfo image = decoder.Identify(Configuration.Default, stream);
                ImageMetaData meta = image.MetaData;
                Assert.Equal(xResolution, meta.HorizontalResolution);
                Assert.Equal(yResolution, meta.VerticalResolution);
                Assert.Equal(resolutionUnit, meta.ResolutionUnits);
            }
        }
    }
}