Add tests for exclude filter

src/ImageSharp/Formats/Png/IPngEncoderOptions.cs

@@ -61,6 +61,6 @@ namespace SixLabors.ImageSharp.Formats.Png
         /// <summary>
         /// Gets the optimize method.
         /// </summary>
-        PngChunkFilter? OptimizeMethod { get; }
+        PngChunkFilter? ChunkFilter { get; }
     }
 }

src/ImageSharp/Formats/Png/PngEncoder.cs

@@ -63,9 +63,9 @@ namespace SixLabors.ImageSharp.Formats.Png
         public PngInterlaceMode? InterlaceMethod { get; set; }
 
         /// <summary>
-        /// Gets or sets the optimize method.
+        /// Gets or sets the chunk filter. This can be used to exclude some ancillary chunks from being written.
         /// </summary>
-        public PngChunkFilter? OptimizeMethod { get; set; }
+        public PngChunkFilter? ChunkFilter { get; set; }
 
         /// <summary>
         /// Encodes the image to the specified stream from the <see cref="Image{TPixel}"/>.

src/ImageSharp/Formats/Png/PngEncoderCore.cs

@@ -145,7 +145,7 @@ namespace SixLabors.ImageSharp.Formats.Png
             PngMetadata pngMetadata = metadata.GetFormatMetadata(PngFormat.Instance);
             PngEncoderOptionsHelpers.AdjustOptions<TPixel>(this.options, pngMetadata, out this.use16Bit, out this.bytesPerPixel);
             IndexedImageFrame<TPixel> quantized;
-            if (((this.options.OptimizeMethod ?? PngChunkFilter.None) & PngChunkFilter.MakeTransparentBlack) == PngChunkFilter.MakeTransparentBlack)
+            if (((this.options.ChunkFilter ?? PngChunkFilter.None) & PngChunkFilter.MakeTransparentBlack) == PngChunkFilter.MakeTransparentBlack)
             {
                 using (Image<TPixel> tempImage = image.Clone())
                 {
@@ -182,7 +182,7 @@ namespace SixLabors.ImageSharp.Formats.Png
 
             this.WriteHeaderChunk(stream);
 
-            if (((this.options.OptimizeMethod ?? PngChunkFilter.None) & PngChunkFilter.ExcludeGammaChunk) != PngChunkFilter.ExcludeGammaChunk)
+            if (((this.options.ChunkFilter ?? PngChunkFilter.None) & PngChunkFilter.ExcludeGammaChunk) != PngChunkFilter.ExcludeGammaChunk)
             {
                 this.WriteGammaChunk(stream);
             }
@@ -190,17 +190,17 @@ namespace SixLabors.ImageSharp.Formats.Png
             this.WritePaletteChunk(stream, quantized);
             this.WriteTransparencyChunk(stream, pngMetadata);
 
-            if (((this.options.OptimizeMethod ?? PngChunkFilter.None) & PngChunkFilter.ExcludePhysicalChunk) != PngChunkFilter.ExcludePhysicalChunk)
+            if (((this.options.ChunkFilter ?? PngChunkFilter.None) & PngChunkFilter.ExcludePhysicalChunk) != PngChunkFilter.ExcludePhysicalChunk)
             {
                 this.WritePhysicalChunk(stream, metadata);
             }
 
-            if (((this.options.OptimizeMethod ?? PngChunkFilter.None) & PngChunkFilter.ExcludeExifChunk) != PngChunkFilter.ExcludeExifChunk)
+            if (((this.options.ChunkFilter ?? PngChunkFilter.None) & PngChunkFilter.ExcludeExifChunk) != PngChunkFilter.ExcludeExifChunk)
             {
                 this.WriteExifChunk(stream, metadata);
             }
 
-            if (((this.options.OptimizeMethod ?? PngChunkFilter.None) & PngChunkFilter.ExcludeTextChunks) != PngChunkFilter.ExcludeTextChunks)
+            if (((this.options.ChunkFilter ?? PngChunkFilter.None) & PngChunkFilter.ExcludeTextChunks) != PngChunkFilter.ExcludeTextChunks)
             {
                 this.WriteTextChunks(stream, pngMetadata);
             }

src/ImageSharp/Formats/Png/PngEncoderOptions.cs

@@ -29,7 +29,7 @@ namespace SixLabors.ImageSharp.Formats.Png
             this.Quantizer = source.Quantizer;
             this.Threshold = source.Threshold;
             this.InterlaceMethod = source.InterlaceMethod;
-            this.OptimizeMethod = source.OptimizeMethod;
+            this.ChunkFilter = source.ChunkFilter;
         }
 
         /// <summary>
@@ -83,6 +83,6 @@ namespace SixLabors.ImageSharp.Formats.Png
         /// <summary>
         /// Gets or sets a the optimize method.
         /// </summary>
-        public PngChunkFilter? OptimizeMethod { get; set; }
+        public PngChunkFilter? ChunkFilter { get; set; }
     }
 }

tests/ImageSharp.Tests/Formats/Png/PngEncoderTests.Chunks.cs

@@ -0,0 +1,242 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Buffers.Binary;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.IO;
+using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.PixelFormats;
+using Xunit;
+
+// ReSharper disable InconsistentNaming
+namespace SixLabors.ImageSharp.Tests.Formats.Png
+{
+    public partial class PngEncoderTests
+    {
+        [Fact]
+        public void HeaderChunk_ComesFirst()
+        {
+            // arrange
+            var testFile = TestFile.Create(TestImages.Png.PngWithMetadata);
+            using Image<Rgba32> input = testFile.CreateRgba32Image();
+            using var memStream = new MemoryStream();
+
+            // act
+            input.Save(memStream, PngEncoder);
+
+            // assert
+            memStream.Position = 0;
+            Span<byte> bytesSpan = memStream.ToArray().AsSpan(8); // Skip header.
+            BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(0, 4));
+            var type = (PngChunkType)BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(4, 4));
+            Assert.Equal(PngChunkType.Header, type);
+        }
+
+        [Fact]
+        public void EndChunk_IsLast()
+        {
+            // arrange
+            var testFile = TestFile.Create(TestImages.Png.PngWithMetadata);
+            using Image<Rgba32> input = testFile.CreateRgba32Image();
+            using var memStream = new MemoryStream();
+
+            // act
+            input.Save(memStream, PngEncoder);
+
+            // assert
+            memStream.Position = 0;
+            Span<byte> bytesSpan = memStream.ToArray().AsSpan(8); // Skip header.
+            bool endChunkFound = false;
+            while (bytesSpan.Length > 0)
+            {
+                int length = BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(0, 4));
+                var type = (PngChunkType)BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(4, 4));
+                Assert.False(endChunkFound);
+                if (type == PngChunkType.End)
+                {
+                    endChunkFound = true;
+                }
+
+                bytesSpan = bytesSpan.Slice(4 + 4 + length + 4);
+            }
+        }
+
+        [Theory]
+        [InlineData(PngChunkType.Gamma)]
+        [InlineData(PngChunkType.Chroma)]
+        [InlineData(PngChunkType.EmbeddedColorProfile)]
+        [InlineData(PngChunkType.SignificantBits)]
+        [InlineData(PngChunkType.StandardRgbColourSpace)]
+        public void Chunk_ComesBeforePlteAndIDat(object chunkTypeObj)
+        {
+            // arrange
+            var chunkType = (PngChunkType)chunkTypeObj;
+            var testFile = TestFile.Create(TestImages.Png.PngWithMetadata);
+            using Image<Rgba32> input = testFile.CreateRgba32Image();
+            using var memStream = new MemoryStream();
+
+            // act
+            input.Save(memStream, PngEncoder);
+
+            // assert
+            memStream.Position = 0;
+            Span<byte> bytesSpan = memStream.ToArray().AsSpan(8); // Skip header.
+            bool palFound = false;
+            bool dataFound = false;
+            while (bytesSpan.Length > 0)
+            {
+                int length = BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(0, 4));
+                var type = (PngChunkType)BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(4, 4));
+                if (chunkType == type)
+                {
+                    Assert.False(palFound || dataFound, $"{chunkType} chunk should come before data and palette chunk");
+                }
+
+                switch (type)
+                {
+                    case PngChunkType.Data:
+                        dataFound = true;
+                        break;
+                    case PngChunkType.Palette:
+                        palFound = true;
+                        break;
+                }
+
+                bytesSpan = bytesSpan.Slice(4 + 4 + length + 4);
+            }
+        }
+
+        [Theory]
+        [InlineData(PngChunkType.Physical)]
+        [InlineData(PngChunkType.SuggestedPalette)]
+        public void Chunk_ComesBeforeIDat(object chunkTypeObj)
+        {
+            // arrange
+            var chunkType = (PngChunkType)chunkTypeObj;
+            var testFile = TestFile.Create(TestImages.Png.PngWithMetadata);
+            using Image<Rgba32> input = testFile.CreateRgba32Image();
+            using var memStream = new MemoryStream();
+
+            // act
+            input.Save(memStream, PngEncoder);
+
+            // assert
+            memStream.Position = 0;
+            Span<byte> bytesSpan = memStream.ToArray().AsSpan(8); // Skip header.
+            bool dataFound = false;
+            while (bytesSpan.Length > 0)
+            {
+                int length = BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(0, 4));
+                var type = (PngChunkType)BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(4, 4));
+                if (chunkType == type)
+                {
+                    Assert.False(dataFound, $"{chunkType} chunk should come before data chunk");
+                }
+
+                if (type == PngChunkType.Data)
+                {
+                    dataFound = true;
+                }
+
+                bytesSpan = bytesSpan.Slice(4 + 4 + length + 4);
+            }
+        }
+
+        [Theory]
+        [InlineData(PngChunkFilter.ExcludeGammaChunk)]
+        [InlineData(PngChunkFilter.ExcludeExifChunk)]
+        [InlineData(PngChunkFilter.ExcludePhysicalChunk)]
+        [InlineData(PngChunkFilter.ExcludeTextChunks)]
+        [InlineData(PngChunkFilter.ExcludeAll)]
+        public void ExcludeFilter_Works(object filterObj)
+        {
+            // arrange
+            var chunkFilter = (PngChunkFilter)filterObj;
+            var testFile = TestFile.Create(TestImages.Png.PngWithMetadata);
+            using Image<Rgba32> input = testFile.CreateRgba32Image();
+            using var memStream = new MemoryStream();
+            var encoder = new PngEncoder() { ChunkFilter = chunkFilter, TextCompressionThreshold = 8 };
+            var excludedChunkTypes = new List<PngChunkType>();
+            switch (chunkFilter)
+            {
+                case PngChunkFilter.ExcludeGammaChunk:
+                    excludedChunkTypes.Add(PngChunkType.Gamma);
+                    break;
+                case PngChunkFilter.ExcludeExifChunk:
+                    excludedChunkTypes.Add(PngChunkType.Exif);
+                    break;
+                case PngChunkFilter.ExcludePhysicalChunk:
+                    excludedChunkTypes.Add(PngChunkType.Physical);
+                    break;
+                case PngChunkFilter.ExcludeTextChunks:
+                    excludedChunkTypes.Add(PngChunkType.Text);
+                    excludedChunkTypes.Add(PngChunkType.InternationalText);
+                    excludedChunkTypes.Add(PngChunkType.CompressedText);
+                    break;
+                case PngChunkFilter.ExcludeAll:
+                    excludedChunkTypes.Add(PngChunkType.Gamma);
+                    excludedChunkTypes.Add(PngChunkType.Exif);
+                    excludedChunkTypes.Add(PngChunkType.Physical);
+                    excludedChunkTypes.Add(PngChunkType.Text);
+                    excludedChunkTypes.Add(PngChunkType.InternationalText);
+                    excludedChunkTypes.Add(PngChunkType.CompressedText);
+                    break;
+            }
+
+            // act
+            input.Save(memStream, encoder);
+
+            // assert
+            Assert.True(excludedChunkTypes.Count > 0);
+            memStream.Position = 0;
+            Span<byte> bytesSpan = memStream.ToArray().AsSpan(8); // Skip header.
+            while (bytesSpan.Length > 0)
+            {
+                int length = BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(0, 4));
+                var chunkType = (PngChunkType)BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(4, 4));
+                Assert.False(excludedChunkTypes.Contains(chunkType), $"{chunkType} chunk should have been excluded");
+
+                bytesSpan = bytesSpan.Slice(4 + 4 + length + 4);
+            }
+        }
+
+        [Fact]
+        public void ExcludeFilter_WithNone_DoesNotExcludeChunks()
+        {
+            // arrange
+            var testFile = TestFile.Create(TestImages.Png.PngWithMetadata);
+            using Image<Rgba32> input = testFile.CreateRgba32Image();
+            using var memStream = new MemoryStream();
+            var encoder = new PngEncoder() { ChunkFilter = PngChunkFilter.None, TextCompressionThreshold = 8 };
+            var expectedChunkTypes = new List<PngChunkType>()
+            {
+                PngChunkType.Header,
+                PngChunkType.Gamma,
+                PngChunkType.Palette,
+                PngChunkType.Transparency,
+                PngChunkType.InternationalText,
+                PngChunkType.Text,
+                PngChunkType.CompressedText,
+                PngChunkType.Exif,
+                PngChunkType.Physical,
+                PngChunkType.Data,
+                PngChunkType.End,
+            };
+
+            // act
+            input.Save(memStream, encoder);
+            memStream.Position = 0;
+            Span<byte> bytesSpan = memStream.ToArray().AsSpan(8); // Skip header.
+            while (bytesSpan.Length > 0)
+            {
+                int length = BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(0, 4));
+                var chunkType = (PngChunkType)BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(4, 4));
+                Assert.True(expectedChunkTypes.Contains(chunkType), $"{chunkType} chunk should have been present");
+
+                bytesSpan = bytesSpan.Slice(4 + 4 + length + 4);
+            }
+        }
+    }
+}

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

@@ -2,8 +2,6 @@
 // Licensed under the Apache License, Version 2.0.
 
 // ReSharper disable InconsistentNaming
-using System;
-using System.Buffers.Binary;
 using System.IO;
 using System.Linq;
 
@@ -18,7 +16,7 @@ using Xunit;
 
 namespace SixLabors.ImageSharp.Tests.Formats.Png
 {
-    public class PngEncoderTests
+    public partial class PngEncoderTests
     {
         private static PngEncoder PngEncoder => new PngEncoder();
 
@@ -221,7 +219,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Png
         [WithTestPatternImages(24, 24, PixelTypes.Rgb48, PngColorType.Grayscale, PngBitDepth.Bit16)]
         [WithTestPatternImages(24, 24, PixelTypes.Rgba32, PngColorType.GrayscaleWithAlpha, PngBitDepth.Bit8)]
         [WithTestPatternImages(24, 24, PixelTypes.Rgba64, PngColorType.GrayscaleWithAlpha, PngBitDepth.Bit16)]
-        public void WorksWithAllBitDepthsOptimized<TPixel>(TestImageProvider<TPixel> provider, PngColorType pngColorType, PngBitDepth pngBitDepth)
+        public void WorksWithAllBitDepthsAndExcludeAllFilter<TPixel>(TestImageProvider<TPixel> provider, PngColorType pngColorType, PngBitDepth pngBitDepth)
           where TPixel : unmanaged, IPixel<TPixel>
         {
             foreach (PngInterlaceMode interlaceMode in InterlaceMode)
@@ -435,126 +433,6 @@ namespace SixLabors.ImageSharp.Tests.Formats.Png
             }
         }
 
-        [Fact]
-        public void HeaderChunk_ComesFirst()
-        {
-            var testFile = TestFile.Create(TestImages.Png.PngWithMetadata);
-            using Image<Rgba32> input = testFile.CreateRgba32Image();
-            using var memStream = new MemoryStream();
-            input.Save(memStream, PngEncoder);
-            memStream.Position = 0;
-
-            // Skip header.
-            Span<byte> bytesSpan = memStream.ToArray().AsSpan(8);
-            BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(0, 4));
-            var type = (PngChunkType)BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(4, 4));
-            Assert.Equal(PngChunkType.Header, type);
-        }
-
-        [Fact]
-        public void EndChunk_IsLast()
-        {
-            var testFile = TestFile.Create(TestImages.Png.PngWithMetadata);
-            using Image<Rgba32> input = testFile.CreateRgba32Image();
-            using var memStream = new MemoryStream();
-            input.Save(memStream, PngEncoder);
-            memStream.Position = 0;
-
-            // Skip header.
-            Span<byte> bytesSpan = memStream.ToArray().AsSpan(8);
-
-            bool endChunkFound = false;
-            while (bytesSpan.Length > 0)
-            {
-                int length = BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(0, 4));
-                var type = (PngChunkType)BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(4, 4));
-                Assert.False(endChunkFound);
-                if (type == PngChunkType.End)
-                {
-                    endChunkFound = true;
-                }
-
-                bytesSpan = bytesSpan.Slice(4 + 4 + length + 4);
-            }
-        }
-
-        [Theory]
-        [InlineData(PngChunkType.Gamma)]
-        [InlineData(PngChunkType.Chroma)]
-        [InlineData(PngChunkType.EmbeddedColorProfile)]
-        [InlineData(PngChunkType.SignificantBits)]
-        [InlineData(PngChunkType.StandardRgbColourSpace)]
-        public void Chunk_ComesBeforePlteAndIDat(object chunkTypeObj)
-        {
-            var chunkType = (PngChunkType)chunkTypeObj;
-            var testFile = TestFile.Create(TestImages.Png.PngWithMetadata);
-            using Image<Rgba32> input = testFile.CreateRgba32Image();
-            using var memStream = new MemoryStream();
-            input.Save(memStream, PngEncoder);
-            memStream.Position = 0;
-
-            // Skip header.
-            Span<byte> bytesSpan = memStream.ToArray().AsSpan(8);
-
-            bool palFound = false;
-            bool dataFound = false;
-            while (bytesSpan.Length > 0)
-            {
-                int length = BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(0, 4));
-                var type = (PngChunkType)BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(4, 4));
-                if (chunkType == type)
-                {
-                    Assert.False(palFound || dataFound, $"{chunkType} chunk should come before data and palette chunk");
-                }
-
-                switch (type)
-                {
-                    case PngChunkType.Data:
-                        dataFound = true;
-                        break;
-                    case PngChunkType.Palette:
-                        palFound = true;
-                        break;
-                }
-
-                bytesSpan = bytesSpan.Slice(4 + 4 + length + 4);
-            }
-        }
-
-        [Theory]
-        [InlineData(PngChunkType.Physical)]
-        [InlineData(PngChunkType.SuggestedPalette)]
-        public void Chunk_ComesBeforeIDat(object chunkTypeObj)
-        {
-            var chunkType = (PngChunkType)chunkTypeObj;
-            var testFile = TestFile.Create(TestImages.Png.PngWithMetadata);
-            using Image<Rgba32> input = testFile.CreateRgba32Image();
-            using var memStream = new MemoryStream();
-            input.Save(memStream, PngEncoder);
-            memStream.Position = 0;
-
-            // Skip header.
-            Span<byte> bytesSpan = memStream.ToArray().AsSpan(8);
-
-            bool dataFound = false;
-            while (bytesSpan.Length > 0)
-            {
-                int length = BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(0, 4));
-                var type = (PngChunkType)BinaryPrimitives.ReadInt32BigEndian(bytesSpan.Slice(4, 4));
-                if (chunkType == type)
-                {
-                    Assert.False(dataFound, $"{chunkType} chunk should come before data chunk");
-                }
-
-                if (type == PngChunkType.Data)
-                {
-                    dataFound = true;
-                }
-
-                bytesSpan = bytesSpan.Slice(4 + 4 + length + 4);
-            }
-        }
-
         [Theory]
         [WithTestPatternImages(587, 821, PixelTypes.Rgba32)]
         [WithTestPatternImages(677, 683, PixelTypes.Rgba32)]
@@ -602,7 +480,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Png
                     BitDepth = bitDepth,
                     Quantizer = new WuQuantizer(new QuantizerOptions { MaxColors = paletteSize }),
                     InterlaceMethod = interlaceMode,
-                    OptimizeMethod = optimizeMethod,
+                    ChunkFilter = optimizeMethod,
                 };
 
                 string pngColorTypeInfo = appendPngColorType ? pngColorType.ToString() : string.Empty;