Add PngWriteDefines to Magick.NET (#1661)

src/Magick.NET/Formats/Png/PngChunkFlags.cs

@@ -0,0 +1,80 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+
+namespace ImageMagick.Formats;
+
+/// <summary>
+/// Specifies the chunks to be included or excluded in the PNG image.
+/// This is a flags enumeration, allowing a bitwise combination of its member values.
+/// </summary>
+[System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1300:Element should begin with upper-case letter", Justification = "The lowercase names are consistent with the naming conventions of PNG chunk types as defined in the PNG specification.")]
+[Flags]
+public enum PngChunkFlags
+{
+    /// <summary>
+    /// No chunks specified.
+    /// </summary>
+    None = 0,
+
+    /// <summary>
+    /// Include or exclude all chunks.
+    /// </summary>
+    All = bKGD | cHRM | EXIF | gAMA | iCCP | iTXt | sRGB | tEXt | zCCP | zTXt | date,
+
+    /// <summary>
+    /// Include or exclude bKGD chunk.
+    /// </summary>
+    bKGD = 1,
+
+    /// <summary>
+    /// Include or exclude cHRM chunk.
+    /// </summary>
+    cHRM = 2,
+
+    /// <summary>
+    /// Include or exclude EXIF chunk.
+    /// </summary>
+    EXIF = 4,
+
+    /// <summary>
+    /// Include or exclude gAMA chunk.
+    /// </summary>
+    gAMA = 8,
+
+    /// <summary>
+    /// Include or exclude iCCP chunk.
+    /// </summary>
+    iCCP = 16,
+
+    /// <summary>
+    /// Include or exclude iTXt chunk.
+    /// </summary>
+    iTXt = 32,
+
+    /// <summary>
+    /// Include or exclude sRGB chunk.
+    /// </summary>
+    sRGB = 64,
+
+    /// <summary>
+    /// Include or exclude tEXt chunk.
+    /// </summary>
+    tEXt = 128,
+
+    /// <summary>
+    /// Include or exclude zCCP chunk.
+    /// </summary>
+    zCCP = 256,
+
+    /// <summary>
+    /// Include or exclude zTXt chunk.
+    /// </summary>
+    zTXt = 512,
+
+    /// <summary>
+    /// Include or exclude date chunk.
+    /// </summary>
+    date = 1024,
+}

src/Magick.NET/Formats/Png/PngCompressionFilter.cs

@@ -0,0 +1,35 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
+// Licensed under the Apache License, Version 2.0.
+
+namespace ImageMagick.Formats;
+
+/// <summary>
+/// Specifies the PNG compression filter.
+/// </summary>
+public enum PngCompressionFilter
+{
+    /// <summary>
+    /// 0 - None: No filter.
+    /// </summary>
+    None,
+
+    /// <summary>
+    /// Sub: Subtracts the value of the pixel to the left.
+    /// </summary>
+    Sub,
+
+    /// <summary>
+    /// Up: Subtracts the value of the pixel above.
+    /// </summary>
+    Up,
+
+    /// <summary>
+    /// Average: Uses the average of the left and above pixels.
+    /// </summary>
+    Average,
+
+    /// <summary>
+    /// Paeth: A predictive filter using the Paeth algorithm.
+    /// </summary>
+    Paeth,
+}

src/Magick.NET/Formats/Png/PngCompressionStrategy.cs

@@ -0,0 +1,60 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
+// Licensed under the Apache License, Version 2.0.
+
+namespace ImageMagick.Formats;
+
+/// <summary>
+/// Specifies the PNG compression strategy.
+/// </summary>
+public enum PngCompressionStrategy
+{
+    /// <summary>
+    /// Use the Huffman compression.
+    /// </summary>
+    HuffmanOnly,
+
+    /// <summary>
+    /// Compression algorithm with filtering.
+    /// </summary>
+    Filtered,
+
+    /// <summary>
+    /// Use the Run-Length Encoding compression.
+    /// </summary>
+    RLE,
+
+    /// <summary>
+    /// Use a fixed strategy for compression.
+    /// </summary>
+    Fixed,
+
+    /// <summary>
+    /// Use the default compression strategy.
+    /// </summary>
+    Default,
+
+    /// <summary>
+    /// Adaptive filtering is used when quality is greater than 50 and the image does not have a color map; otherwise, no filtering is used.
+    /// </summary>
+    Adaptive,
+
+    /// <summary>
+    /// Adaptive filtering with minimum-sum-of-absolute-values is used.
+    /// </summary>
+    AdaptiveMinimumSum,
+
+    /// <summary>
+    /// LOCO color transformation (intrapixel differencing) and adaptive filtering with minimum-sum-of-absolute-values are used. Only applicable if the output is MNG.
+    /// </summary>
+    LOCO,
+
+    /// <summary>
+    /// The zlib Z_RLE compression strategy (or the Z_HUFFMAN_ONLY strategy when compression level is 0) is used with adaptive PNG filtering.
+    /// </summary>
+    ZRLEAdaptive,
+
+    /// <summary>
+    /// The zlib Z_RLE compression strategy (or the Z_HUFFMAN_ONLY strategy when compression level is 0) is used with no PNG filtering.
+    /// </summary>
+    ZRLENoFilter,
+}

src/Magick.NET/Formats/Png/PngWriteDefines.cs

@@ -0,0 +1,127 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Collections.Generic;
+
+namespace ImageMagick.Formats;
+
+/// <summary>
+/// Class for defines that are used when a <see cref="MagickFormat.Png"/> image is written.
+/// </summary>
+public sealed class PngWriteDefines : IWriteDefines
+{
+    /// <summary>
+    /// Gets or sets the bit depth for the PNG image.
+    /// Valid values: 1, 2, 4, 8, 16.
+    /// </summary>
+    /// <exception cref="ArgumentException"> Thrown when the bit depth is invalid for the given color type.</exception>
+    public uint? BitDepth { get; set; }
+
+    /// <summary>
+    /// Gets or sets the color type of the image.
+    /// </summary>
+    /// <exception cref="ArgumentException">Thrown when the color type is invalid or unsupported.</exception>
+    public ColorType? ColorType { get; set; }
+
+    /// <summary>
+    /// Gets or sets the compression filter for the PNG image.
+    /// For compression level 0 (quality value less than 10), the Huffman-only strategy is used, which is fastest but not necessarily the worst compression.
+    /// </summary>
+    public PngCompressionFilter? CompressionFilter { get; set; }
+
+    /// <summary>
+    /// Gets or sets the compression level for the PNG image.
+    /// The compression level ranges from 0 to 9, where 0 indicates no compression and 9 indicates maximum compression.
+    /// For compression level 0 (quality value less than 10), the Huffman-only strategy is used, which is the fastest but not necessarily the worst compression.
+    /// </summary>
+    public uint? CompressionLevel { get; set; }
+
+    /// <summary>
+    /// Gets or sets the compression strategy for the PNG image.
+    /// </summary>
+    public PngCompressionStrategy? CompressionStrategy { get; set; }
+
+    /// <summary>
+    /// Gets or sets the chunks to be excluded.
+    /// </summary>
+    public PngChunkFlags? ExcludeChunks { get; set; }
+
+    /// <summary>
+    /// Gets or sets the chunks to be included.
+    /// </summary>
+    public PngChunkFlags? IncludeChunks { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether the iCCP chunk should be preserved when writing the image.
+    /// </summary>
+    public bool PreserveiCCP { get; set; }
+
+    /// <summary>
+    ///  Gets or sets a value indicating whether ColorMap should be preserve when writing the image.
+    /// </summary>
+    public bool PreserveColorMap { get; set; }
+
+    /// <summary>
+    /// Gets the format where the defines are for.
+    /// </summary>
+    public MagickFormat Format
+        => MagickFormat.Png;
+
+    /// <summary>
+    /// Gets the defines that should be set as a define on an image.
+    /// </summary>
+    public IEnumerable<IDefine> Defines
+    {
+        get
+        {
+            if (BitDepth.HasValue)
+                yield return new MagickDefine(Format, "bit-depth", BitDepth.Value);
+
+            if (ColorType.HasValue)
+            {
+                var colorTypeValue = GetPngColorTypeValue(ColorType.Value);
+                yield return new MagickDefine(Format, "color-type", (int)colorTypeValue);
+            }
+
+            if (CompressionFilter.HasValue)
+                yield return new MagickDefine(Format, "compression-filter", (int)CompressionFilter.Value);
+
+            if (CompressionLevel.HasValue)
+                yield return new MagickDefine(Format, "compression-level", CompressionLevel.Value);
+
+            if (CompressionStrategy.HasValue)
+                yield return new MagickDefine(Format, "compression-strategy", (int)CompressionStrategy.Value);
+
+            if (ExcludeChunks.HasValue)
+                yield return new MagickDefine(Format, "exclude-chunks", EnumHelper.ConvertFlags(ExcludeChunks.Value));
+
+            if (IncludeChunks.HasValue)
+                yield return new MagickDefine(Format, "include-chunks", EnumHelper.ConvertFlags(IncludeChunks.Value));
+
+            if (PreserveiCCP)
+                yield return new MagickDefine(Format, "preserve-iCCP", PreserveiCCP);
+
+            if (PreserveColorMap)
+                yield return new MagickDefine(Format, "preserve-colormap", PreserveColorMap);
+        }
+    }
+
+    private int GetPngColorTypeValue(ColorType colorType)
+    {
+        // 0 - Grayscale
+        // 2 - RGB (TrueColor)
+        // 3 - Indexed color type (Palette or PaletteAlpha)
+        // 4 - Grayscale with alpha (GrayscaleAlpha)
+        // 6 - RGB with alpha (TrueColorAlpha)
+        return colorType switch
+        {
+            ImageMagick.ColorType.Grayscale => 0,
+            ImageMagick.ColorType.TrueColor => 2,
+            ImageMagick.ColorType.Palette or ImageMagick.ColorType.PaletteAlpha => 3,
+            ImageMagick.ColorType.GrayscaleAlpha => 4,
+            ImageMagick.ColorType.TrueColorAlpha => 6,
+            _ => throw new ArgumentException($"Unsupported color type: {colorType}"),
+        };
+    }
+}

tests/Magick.NET.Tests/Formats/Png/PngWriteDefinesTests/TheBitDepthProperty.cs

@@ -0,0 +1,38 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
+// Licensed under the Apache License, Version 2.0.
+
+using ImageMagick;
+using ImageMagick.Formats;
+using Xunit;
+
+namespace Magick.NET.Tests;
+
+public partial class PngWriteDefinesTests
+{
+    public class TheBitDepthProperty
+    {
+        [Fact]
+        public void ShouldSetTheDefine()
+        {
+            using var image = new MagickImage();
+            image.Settings.SetDefines(new PngWriteDefines
+            {
+                BitDepth = 8U,
+            });
+
+            Assert.Equal("8", image.Settings.GetDefine(MagickFormat.Png, "bit-depth"));
+        }
+
+        [Fact]
+        public void ShouldNotSetTheDefineWhenNull()
+        {
+            using var image = new MagickImage();
+            image.Settings.SetDefines(new PngWriteDefines
+            {
+                BitDepth = null,
+            });
+
+            Assert.Null(image.Settings.GetDefine(MagickFormat.Png, "bit-depth"));
+        }
+    }
+}