Merge pull request #1851 from ynse01/pgm-support

Add support for Portable Bitmap images

src/ImageSharp/Advanced/AotCompilerTools.cs

@@ -10,6 +10,7 @@ using SixLabors.ImageSharp.Formats.Bmp;
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Formats.Jpeg;
 using SixLabors.ImageSharp.Formats.Jpeg.Components;
+using SixLabors.ImageSharp.Formats.Pbm;
 using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Formats.Tga;
 using SixLabors.ImageSharp.Formats.Tiff;
@@ -200,6 +201,7 @@ namespace SixLabors.ImageSharp.Advanced
             default(BmpEncoderCore).Encode<TPixel>(default, default, default);
             default(GifEncoderCore).Encode<TPixel>(default, default, default);
             default(JpegEncoderCore).Encode<TPixel>(default, default, default);
+            default(PbmEncoderCore).Encode<TPixel>(default, default, default);
             default(PngEncoderCore).Encode<TPixel>(default, default, default);
             default(TgaEncoderCore).Encode<TPixel>(default, default, default);
             default(TiffEncoderCore).Encode<TPixel>(default, default, default);
@@ -217,6 +219,7 @@ namespace SixLabors.ImageSharp.Advanced
             default(BmpDecoderCore).Decode<TPixel>(default, default, default);
             default(GifDecoderCore).Decode<TPixel>(default, default, default);
             default(JpegDecoderCore).Decode<TPixel>(default, default, default);
+            default(PbmDecoderCore).Decode<TPixel>(default, default, default);
             default(PngDecoderCore).Decode<TPixel>(default, default, default);
             default(TgaDecoderCore).Decode<TPixel>(default, default, default);
             default(TiffDecoderCore).Decode<TPixel>(default, default, default);
@@ -234,6 +237,7 @@ namespace SixLabors.ImageSharp.Advanced
             AotCompileImageEncoder<TPixel, BmpEncoder>();
             AotCompileImageEncoder<TPixel, GifEncoder>();
             AotCompileImageEncoder<TPixel, JpegEncoder>();
+            AotCompileImageEncoder<TPixel, PbmEncoder>();
             AotCompileImageEncoder<TPixel, PngEncoder>();
             AotCompileImageEncoder<TPixel, TgaEncoder>();
             AotCompileImageEncoder<TPixel, TiffEncoder>();
@@ -251,6 +255,7 @@ namespace SixLabors.ImageSharp.Advanced
             AotCompileImageDecoder<TPixel, BmpDecoder>();
             AotCompileImageDecoder<TPixel, GifDecoder>();
             AotCompileImageDecoder<TPixel, JpegDecoder>();
+            AotCompileImageDecoder<TPixel, PbmDecoder>();
             AotCompileImageDecoder<TPixel, PngDecoder>();
             AotCompileImageDecoder<TPixel, TgaDecoder>();
             AotCompileImageDecoder<TPixel, TiffDecoder>();

src/ImageSharp/Configuration.cs

@@ -8,6 +8,7 @@ using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Bmp;
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Formats.Pbm;
 using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Formats.Tga;
 using SixLabors.ImageSharp.Formats.Tiff;
@@ -209,6 +210,7 @@ namespace SixLabors.ImageSharp
         /// <see cref="JpegConfigurationModule"/>
         /// <see cref="GifConfigurationModule"/>
         /// <see cref="BmpConfigurationModule"/>.
+        /// <see cref="PbmConfigurationModule"/>.
         /// <see cref="TgaConfigurationModule"/>.
         /// <see cref="TiffConfigurationModule"/>.
         /// <see cref="WebpConfigurationModule"/>.
@@ -219,6 +221,7 @@ namespace SixLabors.ImageSharp
                 new JpegConfigurationModule(),
                 new GifConfigurationModule(),
                 new BmpConfigurationModule(),
+                new PbmConfigurationModule(),
                 new TgaConfigurationModule(),
                 new TiffConfigurationModule(),
                 new WebpConfigurationModule());

src/ImageSharp/Formats/ImageExtensions.Save.cs

@@ -10,6 +10,7 @@ using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Formats.Bmp;
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Formats.Pbm;
 using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Formats.Tga;
 using SixLabors.ImageSharp.Formats.Webp;
@@ -331,6 +332,109 @@ namespace SixLabors.ImageSharp
                 encoder ?? source.GetConfiguration().ImageFormatsManager.FindEncoder(JpegFormat.Instance),
                 cancellationToken);
 
+        /// <summary>
+        /// Saves the image to the given stream with the Pbm format.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="path">The file path to save the image to.</param>
+        /// <exception cref="System.ArgumentNullException">Thrown if the path is null.</exception>
+        public static void SaveAsPbm(this Image source, string path) => SaveAsPbm(source, path, null);
+
+        /// <summary>
+        /// Saves the image to the given stream with the Pbm format.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="path">The file path to save the image to.</param>
+        /// <exception cref="System.ArgumentNullException">Thrown if the path is null.</exception>
+        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+        public static Task SaveAsPbmAsync(this Image source, string path) => SaveAsPbmAsync(source, path, null);
+
+        /// <summary>
+        /// Saves the image to the given stream with the Pbm format.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="path">The file path to save the image to.</param>
+        /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
+        /// <exception cref="System.ArgumentNullException">Thrown if the path is null.</exception>
+        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+        public static Task SaveAsPbmAsync(this Image source, string path, CancellationToken cancellationToken)
+            => SaveAsPbmAsync(source, path, null, cancellationToken);
+
+        /// <summary>
+        /// Saves the image to the given stream with the Pbm format.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="path">The file path to save the image to.</param>
+        /// <param name="encoder">The encoder to save the image with.</param>
+        /// <exception cref="System.ArgumentNullException">Thrown if the path is null.</exception>
+        public static void SaveAsPbm(this Image source, string path, PbmEncoder encoder) =>
+            source.Save(
+                path,
+                encoder ?? source.GetConfiguration().ImageFormatsManager.FindEncoder(PbmFormat.Instance));
+
+        /// <summary>
+        /// Saves the image to the given stream with the Pbm format.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="path">The file path to save the image to.</param>
+        /// <param name="encoder">The encoder to save the image with.</param>
+        /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
+        /// <exception cref="System.ArgumentNullException">Thrown if the path is null.</exception>
+        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+        public static Task SaveAsPbmAsync(this Image source, string path, PbmEncoder encoder, CancellationToken cancellationToken = default) =>
+            source.SaveAsync(
+                path,
+                encoder ?? source.GetConfiguration().ImageFormatsManager.FindEncoder(PbmFormat.Instance),
+                cancellationToken);
+
+        /// <summary>
+        /// Saves the image to the given stream with the Pbm format.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="stream">The stream to save the image to.</param>
+        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        public static void SaveAsPbm(this Image source, Stream stream)
+            => SaveAsPbm(source, stream, null);
+
+        /// <summary>
+        /// Saves the image to the given stream with the Pbm format.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="stream">The stream to save the image to.</param>
+        /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
+        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+        public static Task SaveAsPbmAsync(this Image source, Stream stream, CancellationToken cancellationToken = default)
+            => SaveAsPbmAsync(source, stream, null, cancellationToken);
+
+        /// <summary>
+        /// Saves the image to the given stream with the Pbm format.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="stream">The stream to save the image to.</param>
+        /// <param name="encoder">The encoder to save the image with.</param>
+        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+        public static void SaveAsPbm(this Image source, Stream stream, PbmEncoder encoder)
+            => source.Save(
+                stream,
+                encoder ?? source.GetConfiguration().ImageFormatsManager.FindEncoder(PbmFormat.Instance));
+
+        /// <summary>
+        /// Saves the image to the given stream with the Pbm format.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="stream">The stream to save the image to.</param>
+        /// <param name="encoder">The encoder to save the image with.</param>
+        /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
+        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+        public static Task SaveAsPbmAsync(this Image source, Stream stream, PbmEncoder encoder, CancellationToken cancellationToken = default) =>
+            source.SaveAsync(
+                stream,
+                encoder ?? source.GetConfiguration().ImageFormatsManager.FindEncoder(PbmFormat.Instance),
+                cancellationToken);
+
         /// <summary>
         /// Saves the image to the given stream with the Png format.
         /// </summary>

src/ImageSharp/Formats/ImageExtensions.Save.tt

@@ -15,6 +15,7 @@ using SixLabors.ImageSharp.Advanced;
         "Bmp",
         "Gif",
         "Jpeg",
+        "Pbm",
         "Png",
         "Tga",
         "Webp",

src/ImageSharp/Formats/Pbm/BinaryDecoder.cs

@@ -0,0 +1,194 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Buffers;
+using SixLabors.ImageSharp.IO;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Pixel decoding methods for the PBM binary encoding.
+    /// </summary>
+    internal class BinaryDecoder
+    {
+        private static L8 white = new(255);
+        private static L8 black = new(0);
+
+        /// <summary>
+        /// Decode the specified pixels.
+        /// </summary>
+        /// <typeparam name="TPixel">The type of pixel to encode to.</typeparam>
+        /// <param name="configuration">The configuration.</param>
+        /// <param name="pixels">The pixel array to encode into.</param>
+        /// <param name="stream">The stream to read the data from.</param>
+        /// <param name="colorType">The ColorType to decode.</param>
+        /// <param name="componentType">Data type of the pixles components.</param>
+        /// <exception cref="InvalidImageContentException">
+        /// Thrown if an invalid combination of setting is requested.
+        /// </exception>
+        public static void Process<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream, PbmColorType colorType, PbmComponentType componentType)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            if (colorType == PbmColorType.Grayscale)
+            {
+                if (componentType == PbmComponentType.Byte)
+                {
+                    ProcessGrayscale(configuration, pixels, stream);
+                }
+                else
+                {
+                    ProcessWideGrayscale(configuration, pixels, stream);
+                }
+            }
+            else if (colorType == PbmColorType.Rgb)
+            {
+                if (componentType == PbmComponentType.Byte)
+                {
+                    ProcessRgb(configuration, pixels, stream);
+                }
+                else
+                {
+                    ProcessWideRgb(configuration, pixels, stream);
+                }
+            }
+            else
+            {
+                ProcessBlackAndWhite(configuration, pixels, stream);
+            }
+        }
+
+        private static void ProcessGrayscale<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            const int bytesPerPixel = 1;
+            int width = pixels.Width;
+            int height = pixels.Height;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<byte> row = allocator.Allocate<byte>(width * bytesPerPixel);
+            Span<byte> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                stream.Read(rowSpan);
+                Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.FromL8Bytes(
+                    configuration,
+                    rowSpan,
+                    pixelSpan,
+                    width);
+            }
+        }
+
+        private static void ProcessWideGrayscale<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            const int bytesPerPixel = 2;
+            int width = pixels.Width;
+            int height = pixels.Height;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<byte> row = allocator.Allocate<byte>(width * bytesPerPixel);
+            Span<byte> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                stream.Read(rowSpan);
+                Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.FromL16Bytes(
+                    configuration,
+                    rowSpan,
+                    pixelSpan,
+                    width);
+            }
+        }
+
+        private static void ProcessRgb<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            const int bytesPerPixel = 3;
+            int width = pixels.Width;
+            int height = pixels.Height;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<byte> row = allocator.Allocate<byte>(width * bytesPerPixel);
+            Span<byte> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                stream.Read(rowSpan);
+                Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.FromRgb24Bytes(
+                    configuration,
+                    rowSpan,
+                    pixelSpan,
+                    width);
+            }
+        }
+
+        private static void ProcessWideRgb<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            const int bytesPerPixel = 6;
+            int width = pixels.Width;
+            int height = pixels.Height;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<byte> row = allocator.Allocate<byte>(width * bytesPerPixel);
+            Span<byte> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                stream.Read(rowSpan);
+                Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.FromRgb48Bytes(
+                    configuration,
+                    rowSpan,
+                    pixelSpan,
+                    width);
+            }
+        }
+
+        private static void ProcessBlackAndWhite<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = pixels.Width;
+            int height = pixels.Height;
+            int startBit = 0;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<L8> row = allocator.Allocate<L8>(width);
+            Span<L8> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                for (int x = 0; x < width;)
+                {
+                    int raw = stream.ReadByte();
+                    int bit = startBit;
+                    startBit = 0;
+                    for (; bit < 8; bit++)
+                    {
+                        bool bitValue = (raw & (0x80 >> bit)) != 0;
+                        rowSpan[x] = bitValue ? black : white;
+                        x++;
+                        if (x == width)
+                        {
+                            startBit = (bit + 1) & 7; // Round off to below 8.
+                            if (startBit != 0)
+                            {
+                                stream.Seek(-1, System.IO.SeekOrigin.Current);
+                            }
+
+                            break;
+                        }
+                    }
+                }
+
+                Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.FromL8(
+                    configuration,
+                    rowSpan,
+                    pixelSpan);
+            }
+        }
+    }
+}

src/ImageSharp/Formats/Pbm/BinaryEncoder.cs

@@ -0,0 +1,208 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Buffers;
+using System.IO;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Pixel encoding methods for the PBM binary encoding.
+    /// </summary>
+    internal class BinaryEncoder
+    {
+        /// <summary>
+        /// Decode pixels into the PBM binary encoding.
+        /// </summary>
+        /// <typeparam name="TPixel">The type of input pixel.</typeparam>
+        /// <param name="configuration">The configuration.</param>
+        /// <param name="stream">The bytestream to write to.</param>
+        /// <param name="image">The input image.</param>
+        /// <param name="colorType">The ColorType to use.</param>
+        /// <param name="componentType">Data type of the pixles components.</param>
+        /// <exception cref="InvalidImageContentException">
+        /// Thrown if an invalid combination of setting is requested.
+        /// </exception>
+        public static void WritePixels<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image, PbmColorType colorType, PbmComponentType componentType)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            if (colorType == PbmColorType.Grayscale)
+            {
+                if (componentType == PbmComponentType.Byte)
+                {
+                    WriteGrayscale(configuration, stream, image);
+                }
+                else
+                {
+                    WriteWideGrayscale(configuration, stream, image);
+                }
+            }
+            else if (colorType == PbmColorType.Rgb)
+            {
+                if (componentType == PbmComponentType.Byte)
+                {
+                    WriteRgb(configuration, stream, image);
+                }
+                else
+                {
+                    WriteWideRgb(configuration, stream, image);
+                }
+            }
+            else
+            {
+                WriteBlackAndWhite(configuration, stream, image);
+            }
+        }
+
+        private static void WriteGrayscale<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = image.Width;
+            int height = image.Height;
+            Buffer2D<TPixel> pixelBuffer = image.PixelBuffer;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<byte> row = allocator.Allocate<byte>(width);
+            Span<byte> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
+
+                PixelOperations<TPixel>.Instance.ToL8Bytes(
+                    configuration,
+                    pixelSpan,
+                    rowSpan,
+                    width);
+
+                stream.Write(rowSpan);
+            }
+        }
+
+        private static void WriteWideGrayscale<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            const int bytesPerPixel = 2;
+            int width = image.Width;
+            int height = image.Height;
+            Buffer2D<TPixel> pixelBuffer = image.PixelBuffer;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<byte> row = allocator.Allocate<byte>(width * bytesPerPixel);
+            Span<byte> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
+
+                PixelOperations<TPixel>.Instance.ToL16Bytes(
+                    configuration,
+                    pixelSpan,
+                    rowSpan,
+                    width);
+
+                stream.Write(rowSpan);
+            }
+        }
+
+        private static void WriteRgb<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            const int bytesPerPixel = 3;
+            int width = image.Width;
+            int height = image.Height;
+            Buffer2D<TPixel> pixelBuffer = image.PixelBuffer;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<byte> row = allocator.Allocate<byte>(width * bytesPerPixel);
+            Span<byte> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
+
+                PixelOperations<TPixel>.Instance.ToRgb24Bytes(
+                    configuration,
+                    pixelSpan,
+                    rowSpan,
+                    width);
+
+                stream.Write(rowSpan);
+            }
+        }
+
+        private static void WriteWideRgb<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            const int bytesPerPixel = 6;
+            int width = image.Width;
+            int height = image.Height;
+            Buffer2D<TPixel> pixelBuffer = image.PixelBuffer;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<byte> row = allocator.Allocate<byte>(width * bytesPerPixel);
+            Span<byte> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
+
+                PixelOperations<TPixel>.Instance.ToRgb48Bytes(
+                    configuration,
+                    pixelSpan,
+                    rowSpan,
+                    width);
+
+                stream.Write(rowSpan);
+            }
+        }
+
+        private static void WriteBlackAndWhite<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = image.Width;
+            int height = image.Height;
+            Buffer2D<TPixel> pixelBuffer = image.PixelBuffer;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<L8> row = allocator.Allocate<L8>(width);
+            Span<L8> rowSpan = row.GetSpan();
+
+            int previousValue = 0;
+            int startBit = 0;
+            for (int y = 0; y < height; y++)
+            {
+                Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
+
+                PixelOperations<TPixel>.Instance.ToL8(
+                    configuration,
+                    pixelSpan,
+                    rowSpan);
+
+                for (int x = 0; x < width;)
+                {
+                    int value = previousValue;
+                    for (int i = startBit; i < 8; i++)
+                    {
+                        if (rowSpan[x].PackedValue < 128)
+                        {
+                            value |= 0x80 >> i;
+                        }
+
+                        x++;
+                        if (x == width)
+                        {
+                            previousValue = value;
+                            startBit = (i + 1) & 7; // Round off to below 8.
+                            break;
+                        }
+                    }
+
+                    if (startBit == 0)
+                    {
+                        stream.WriteByte((byte)value);
+                        previousValue = 0;
+                    }
+                }
+            }
+        }
+    }
+}

src/ImageSharp/Formats/Pbm/BufferedReadStreamExtensions.cs

@@ -0,0 +1,65 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.IO;
+using SixLabors.ImageSharp.IO;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Extensions methods for <see cref="BufferedReadStream"/>.
+    /// </summary>
+    internal static class BufferedReadStreamExtensions
+    {
+        /// <summary>
+        /// Skip over any whitespace or any comments.
+        /// </summary>
+        public static void SkipWhitespaceAndComments(this BufferedReadStream stream)
+        {
+            bool isWhitespace;
+            do
+            {
+                int val = stream.ReadByte();
+
+                // Comments start with '#' and end at the next new-line.
+                if (val == 0x23)
+                {
+                    int innerValue;
+                    do
+                    {
+                        innerValue = stream.ReadByte();
+                    }
+                    while (innerValue != 0x0a);
+
+                    // Continue searching for whitespace.
+                    val = innerValue;
+                }
+
+                isWhitespace = val is 0x09 or 0x0a or 0x0d or 0x20;
+            }
+            while (isWhitespace);
+            stream.Seek(-1, SeekOrigin.Current);
+        }
+
+        /// <summary>
+        /// Read a decimal text value.
+        /// </summary>
+        /// <returns>The integer value of the decimal.</returns>
+        public static int ReadDecimal(this BufferedReadStream stream)
+        {
+            int value = 0;
+            while (true)
+            {
+                int current = stream.ReadByte() - 0x30;
+                if ((uint)current > 9)
+                {
+                    break;
+                }
+
+                value = (value * 10) + current;
+            }
+
+            return value;
+        }
+    }
+}

src/ImageSharp/Formats/Pbm/IPbmEncoderOptions.cs

@@ -0,0 +1,26 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Configuration options for use during PBM encoding.
+    /// </summary>
+    internal interface IPbmEncoderOptions
+    {
+        /// <summary>
+        /// Gets the encoding of the pixels.
+        /// </summary>
+        PbmEncoding? Encoding { get; }
+
+        /// <summary>
+        /// Gets the Color type of the resulting image.
+        /// </summary>
+        PbmColorType? ColorType { get; }
+
+        /// <summary>
+        /// Gets the Data Type of the pixel components.
+        /// </summary>
+        PbmComponentType? ComponentType { get; }
+    }
+}

src/ImageSharp/Formats/Pbm/MetadataExtensions.cs

@@ -0,0 +1,21 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using SixLabors.ImageSharp.Formats.Pbm;
+using SixLabors.ImageSharp.Metadata;
+
+namespace SixLabors.ImageSharp
+{
+    /// <summary>
+    /// Extension methods for the <see cref="ImageMetadata"/> type.
+    /// </summary>
+    public static partial class MetadataExtensions
+    {
+        /// <summary>
+        /// Gets the pbm format specific metadata for the image.
+        /// </summary>
+        /// <param name="metadata">The metadata this method extends.</param>
+        /// <returns>The <see cref="PbmMetadata"/>.</returns>
+        public static PbmMetadata GetPbmMetadata(this ImageMetadata metadata) => metadata.GetFormatMetadata(PbmFormat.Instance);
+    }
+}

src/ImageSharp/Formats/Pbm/PbmColorType.cs

@@ -0,0 +1,26 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Provides enumeration of available PBM color types.
+    /// </summary>
+    public enum PbmColorType : byte
+    {
+        /// <summary>
+        /// PBM
+        /// </summary>
+        BlackAndWhite = 0,
+
+        /// <summary>
+        /// PGM - Greyscale. Single component.
+        /// </summary>
+        Grayscale = 1,
+
+        /// <summary>
+        /// PPM - RGB Color. 3 components.
+        /// </summary>
+        Rgb = 2,
+    }
+}

src/ImageSharp/Formats/Pbm/PbmComponentType.cs

@@ -0,0 +1,26 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// The data type of the components of the pixels.
+    /// </summary>
+    public enum PbmComponentType : byte
+    {
+        /// <summary>
+        /// Single bit per pixel, exclusively for <see cref="PbmColorType.BlackAndWhite"/>.
+        /// </summary>
+        Bit = 0,
+
+        /// <summary>
+        /// 8 bits unsigned integer per component.
+        /// </summary>
+        Byte = 1,
+
+        /// <summary>
+        /// 16 bits unsigned integer per component.
+        /// </summary>
+        Short = 2
+    }
+}

src/ImageSharp/Formats/Pbm/PbmConfigurationModule.cs

@@ -0,0 +1,19 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Registers the image encoders, decoders and mime type detectors for the Pbm format.
+    /// </summary>
+    public sealed class PbmConfigurationModule : IConfigurationModule
+    {
+        /// <inheritdoc/>
+        public void Configure(Configuration configuration)
+        {
+            configuration.ImageFormatsManager.SetEncoder(PbmFormat.Instance, new PbmEncoder());
+            configuration.ImageFormatsManager.SetDecoder(PbmFormat.Instance, new PbmDecoder());
+            configuration.ImageFormatsManager.AddImageFormatDetector(new PbmImageFormatDetector());
+        }
+    }
+}

src/ImageSharp/Formats/Pbm/PbmConstants.cs

@@ -0,0 +1,28 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.Collections.Generic;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Contains PBM constant values defined in the specification.
+    /// </summary>
+    internal static class PbmConstants
+    {
+        /// <summary>
+        /// The maximum allowable pixel value of a ppm image.
+        /// </summary>
+        public const ushort MaxLength = 65535;
+
+        /// <summary>
+        /// The list of mimetypes that equate to a ppm.
+        /// </summary>
+        public static readonly IEnumerable<string> MimeTypes = new[] { "image/x-portable-pixmap", "image/x-portable-anymap" };
+
+        /// <summary>
+        /// The list of file extensions that equate to a ppm.
+        /// </summary>
+        public static readonly IEnumerable<string> FileExtensions = new[] { "ppm", "pbm", "pgm" };
+    }
+}

src/ImageSharp/Formats/Pbm/PbmDecoder.cs

@@ -0,0 +1,79 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Image decoder for reading PGM, PBM or PPM bitmaps from a stream. These images are from
+    /// the family of PNM images.
+    /// <list type="bullet">
+    /// <item>
+    /// <term>PBM</term>
+    /// <description>Black and white images.</description>
+    /// </item>
+    /// <item>
+    /// <term>PGM</term>
+    /// <description>Grayscale images.</description>
+    /// </item>
+    /// <item>
+    /// <term>PPM</term>
+    /// <description>Color images, with RGB pixels.</description>
+    /// </item>
+    /// </list>
+    /// The specification of these images is found at <seealso href="http://netpbm.sourceforge.net/doc/pnm.html"/>.
+    /// </summary>
+    public sealed class PbmDecoder : IImageDecoder, IImageInfoDetector
+    {
+        /// <inheritdoc/>
+        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            Guard.NotNull(stream, nameof(stream));
+
+            var decoder = new PbmDecoderCore(configuration);
+            return decoder.Decode<TPixel>(configuration, stream);
+        }
+
+        /// <inheritdoc />
+        public Image Decode(Configuration configuration, Stream stream)
+            => this.Decode<Rgb24>(configuration, stream);
+
+        /// <inheritdoc/>
+        public Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream, CancellationToken cancellationToken)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            Guard.NotNull(stream, nameof(stream));
+
+            var decoder = new PbmDecoderCore(configuration);
+            return decoder.DecodeAsync<TPixel>(configuration, stream, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public async Task<Image> DecodeAsync(Configuration configuration, Stream stream, CancellationToken cancellationToken)
+            => await this.DecodeAsync<Rgba32>(configuration, stream, cancellationToken)
+            .ConfigureAwait(false);
+
+        /// <inheritdoc/>
+        public IImageInfo Identify(Configuration configuration, Stream stream)
+        {
+            Guard.NotNull(stream, nameof(stream));
+
+            var decoder = new PbmDecoderCore(configuration);
+            return decoder.Identify(configuration, stream);
+        }
+
+        /// <inheritdoc/>
+        public Task<IImageInfo> IdentifyAsync(Configuration configuration, Stream stream, CancellationToken cancellationToken)
+        {
+            Guard.NotNull(stream, nameof(stream));
+
+            var decoder = new PbmDecoderCore(configuration);
+            return decoder.IdentifyAsync(configuration, stream, cancellationToken);
+        }
+    }
+}

src/ImageSharp/Formats/Pbm/PbmDecoderCore.cs

@@ -0,0 +1,195 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Threading;
+using SixLabors.ImageSharp.IO;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.Metadata;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Processing;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Performs the PBM decoding operation.
+    /// </summary>
+    internal sealed class PbmDecoderCore : IImageDecoderInternals
+    {
+        private int maxPixelValue;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PbmDecoderCore" /> class.
+        /// </summary>
+        /// <param name="configuration">The configuration.</param>
+        public PbmDecoderCore(Configuration configuration) => this.Configuration = configuration ?? Configuration.Default;
+
+        /// <inheritdoc />
+        public Configuration Configuration { get; }
+
+        /// <summary>
+        /// Gets the colortype to use
+        /// </summary>
+        public PbmColorType ColorType { get; private set; }
+
+        /// <summary>
+        /// Gets the size of the pixel array
+        /// </summary>
+        public Size PixelSize { get; private set; }
+
+        /// <summary>
+        /// Gets the component data type
+        /// </summary>
+        public PbmComponentType ComponentType { get; private set; }
+
+        /// <summary>
+        /// Gets the Encoding of pixels
+        /// </summary>
+        public PbmEncoding Encoding { get; private set; }
+
+        /// <summary>
+        /// Gets the <see cref="ImageMetadata"/> decoded by this decoder instance.
+        /// </summary>
+        public ImageMetadata Metadata { get; private set; }
+
+        /// <inheritdoc/>
+        Size IImageDecoderInternals.Dimensions => this.PixelSize;
+
+        private bool NeedsUpscaling => this.ColorType != PbmColorType.BlackAndWhite && this.maxPixelValue is not 255 and not 65535;
+
+        /// <inheritdoc/>
+        public Image<TPixel> Decode<TPixel>(BufferedReadStream stream, CancellationToken cancellationToken)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            this.ProcessHeader(stream);
+
+            var image = new Image<TPixel>(this.Configuration, this.PixelSize.Width, this.PixelSize.Height, this.Metadata);
+
+            Buffer2D<TPixel> pixels = image.GetRootFramePixelBuffer();
+
+            this.ProcessPixels(stream, pixels);
+            if (this.NeedsUpscaling)
+            {
+                this.ProcessUpscaling(image);
+            }
+
+            return image;
+        }
+
+        /// <inheritdoc/>
+        public IImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken)
+        {
+            this.ProcessHeader(stream);
+
+            // BlackAndWhite pixels are encoded into a byte.
+            int bitsPerPixel = this.ComponentType == PbmComponentType.Short ? 16 : 8;
+            return new ImageInfo(new PixelTypeInfo(bitsPerPixel), this.PixelSize.Width, this.PixelSize.Height, this.Metadata);
+        }
+
+        /// <summary>
+        /// Processes the ppm header.
+        /// </summary>
+        /// <param name="stream">The input stream.</param>
+        private void ProcessHeader(BufferedReadStream stream)
+        {
+            Span<byte> buffer = stackalloc byte[2];
+
+            int bytesRead = stream.Read(buffer);
+            if (bytesRead != 2 || buffer[0] != 'P')
+            {
+                throw new InvalidImageContentException("Empty or not an PPM image.");
+            }
+
+            switch ((char)buffer[1])
+            {
+                case '1':
+                    // Plain PBM format: 1 component per pixel, boolean value ('0' or '1').
+                    this.ColorType = PbmColorType.BlackAndWhite;
+                    this.Encoding = PbmEncoding.Plain;
+                    break;
+                case '2':
+                    // Plain PGM format: 1 component per pixel, in decimal text.
+                    this.ColorType = PbmColorType.Grayscale;
+                    this.Encoding = PbmEncoding.Plain;
+                    break;
+                case '3':
+                    // Plain PPM format: 3 components per pixel, in decimal text.
+                    this.ColorType = PbmColorType.Rgb;
+                    this.Encoding = PbmEncoding.Plain;
+                    break;
+                case '4':
+                    // Binary PBM format: 1 component per pixel, 8 pixels per byte.
+                    this.ColorType = PbmColorType.BlackAndWhite;
+                    this.Encoding = PbmEncoding.Binary;
+                    break;
+                case '5':
+                    // Binary PGM format: 1 components per pixel, in binary integers.
+                    this.ColorType = PbmColorType.Grayscale;
+                    this.Encoding = PbmEncoding.Binary;
+                    break;
+                case '6':
+                    // Binary PPM format: 3 components per pixel, in binary integers.
+                    this.ColorType = PbmColorType.Rgb;
+                    this.Encoding = PbmEncoding.Binary;
+                    break;
+                case '7':
+                // PAM image: sequence of images.
+                // Not implemented yet
+                default:
+                    throw new InvalidImageContentException("Unknown of not implemented image type encountered.");
+            }
+
+            stream.SkipWhitespaceAndComments();
+            int width = stream.ReadDecimal();
+            stream.SkipWhitespaceAndComments();
+            int height = stream.ReadDecimal();
+            stream.SkipWhitespaceAndComments();
+            if (this.ColorType != PbmColorType.BlackAndWhite)
+            {
+                this.maxPixelValue = stream.ReadDecimal();
+                if (this.maxPixelValue > 255)
+                {
+                    this.ComponentType = PbmComponentType.Short;
+                }
+                else
+                {
+                    this.ComponentType = PbmComponentType.Byte;
+                }
+
+                stream.SkipWhitespaceAndComments();
+            }
+            else
+            {
+                this.ComponentType = PbmComponentType.Bit;
+            }
+
+            this.PixelSize = new Size(width, height);
+            this.Metadata = new ImageMetadata();
+            PbmMetadata meta = this.Metadata.GetPbmMetadata();
+            meta.Encoding = this.Encoding;
+            meta.ColorType = this.ColorType;
+            meta.ComponentType = this.ComponentType;
+        }
+
+        private void ProcessPixels<TPixel>(BufferedReadStream stream, Buffer2D<TPixel> pixels)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            if (this.Encoding == PbmEncoding.Binary)
+            {
+                BinaryDecoder.Process(this.Configuration, pixels, stream, this.ColorType, this.ComponentType);
+            }
+            else
+            {
+                PlainDecoder.Process(this.Configuration, pixels, stream, this.ColorType, this.ComponentType);
+            }
+        }
+
+        private void ProcessUpscaling<TPixel>(Image<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int maxAllocationValue = this.ComponentType == PbmComponentType.Short ? 65535 : 255;
+            float factor = maxAllocationValue / this.maxPixelValue;
+            image.Mutate(x => x.Brightness(factor));
+        }
+    }
+}

src/ImageSharp/Formats/Pbm/PbmEncoder.cs

@@ -0,0 +1,69 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Image encoder for writing an image to a stream as PGM, PBM or PPM bitmap. These images are from
+    /// the family of PNM images.
+    /// <para>
+    /// The PNM formats are a fairly simple image format. They share a plain text header, consisting of:
+    /// signature, width, height and max_pixel_value only. The pixels follow thereafter and can be in
+    /// plain text decimals separated by spaces, or binary encoded.
+    /// <list type="bullet">
+    /// <item>
+    /// <term>PBM</term>
+    /// <description>Black and white images, with 1 representing black and 0 representing white.</description>
+    /// </item>
+    /// <item>
+    /// <term>PGM</term>
+    /// <description>Grayscale images, scaling from 0 to max_pixel_value, 0 representing black and max_pixel_value representing white.</description>
+    /// </item>
+    /// <item>
+    /// <term>PPM</term>
+    /// <description>Color images, with RGB pixels (in that order), with 0 representing black and 2 representing full color.</description>
+    /// </item>
+    /// </list>
+    /// </para>
+    /// The specification of these images is found at <seealso href="http://netpbm.sourceforge.net/doc/pnm.html"/>.
+    /// </summary>
+    public sealed class PbmEncoder : IImageEncoder, IPbmEncoderOptions
+    {
+        /// <summary>
+        /// Gets or sets the Encoding of the pixels.
+        /// </summary>
+        public PbmEncoding? Encoding { get; set; }
+
+        /// <summary>
+        /// Gets or sets the Color type of the resulting image.
+        /// </summary>
+        public PbmColorType? ColorType { get; set; }
+
+        /// <summary>
+        /// Gets or sets the data type of the pixels components.
+        /// </summary>
+        public PbmComponentType? ComponentType { get; set; }
+
+        /// <inheritdoc/>
+        public void Encode<TPixel>(Image<TPixel> image, Stream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            var encoder = new PbmEncoderCore(image.GetConfiguration(), this);
+            encoder.Encode(image, stream);
+        }
+
+        /// <inheritdoc/>
+        public Task EncodeAsync<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            var encoder = new PbmEncoderCore(image.GetConfiguration(), this);
+            return encoder.EncodeAsync(image, stream, cancellationToken);
+        }
+    }
+}

src/ImageSharp/Formats/Pbm/PbmEncoderCore.cs

@@ -0,0 +1,187 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Buffers.Text;
+using System.IO;
+using System.Threading;
+using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Image encoder for writing an image to a stream as a PGM, PBM, PPM or PAM bitmap.
+    /// </summary>
+    internal sealed class PbmEncoderCore : IImageEncoderInternals
+    {
+        private const byte NewLine = (byte)'\n';
+        private const byte Space = (byte)' ';
+        private const byte P = (byte)'P';
+
+        /// <summary>
+        /// The global configuration.
+        /// </summary>
+        private Configuration configuration;
+
+        /// <summary>
+        /// The encoder options.
+        /// </summary>
+        private readonly IPbmEncoderOptions options;
+
+        /// <summary>
+        /// The encoding for the pixels.
+        /// </summary>
+        private PbmEncoding encoding;
+
+        /// <summary>
+        /// Gets the Color type of the resulting image.
+        /// </summary>
+        private PbmColorType colorType;
+
+        /// <summary>
+        /// Gets the maximum pixel value, per component.
+        /// </summary>
+        private PbmComponentType componentType;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PbmEncoderCore"/> class.
+        /// </summary>
+        /// <param name="configuration">The configuration.</param>
+        /// <param name="options">The encoder options.</param>
+        public PbmEncoderCore(Configuration configuration, IPbmEncoderOptions options)
+        {
+            this.configuration = configuration;
+            this.options = options;
+        }
+
+        /// <summary>
+        /// Encodes the image to the specified stream from the <see cref="ImageFrame{TPixel}"/>.
+        /// </summary>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
+        /// <param name="image">The <see cref="ImageFrame{TPixel}"/> to encode from.</param>
+        /// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
+        /// <param name="cancellationToken">The token to request cancellation.</param>
+        public void Encode<TPixel>(Image<TPixel> image, Stream stream, CancellationToken cancellationToken)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            Guard.NotNull(image, nameof(image));
+            Guard.NotNull(stream, nameof(stream));
+
+            this.DeduceOptions(image);
+
+            byte signature = this.DeduceSignature();
+            this.WriteHeader(stream, signature, image.Size());
+
+            this.WritePixels(stream, image.Frames.RootFrame);
+
+            stream.Flush();
+        }
+
+        private void DeduceOptions<TPixel>(Image<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            this.configuration = image.GetConfiguration();
+            PbmMetadata metadata = image.Metadata.GetPbmMetadata();
+            this.encoding = this.options.Encoding ?? metadata.Encoding;
+            this.colorType = this.options.ColorType ?? metadata.ColorType;
+            if (this.colorType != PbmColorType.BlackAndWhite)
+            {
+                this.componentType = this.options.ComponentType ?? metadata.ComponentType;
+            }
+            else
+            {
+                this.componentType = PbmComponentType.Bit;
+            }
+        }
+
+        private byte DeduceSignature()
+        {
+            byte signature;
+            if (this.colorType == PbmColorType.BlackAndWhite)
+            {
+                if (this.encoding == PbmEncoding.Plain)
+                {
+                    signature = (byte)'1';
+                }
+                else
+                {
+                    signature = (byte)'4';
+                }
+            }
+            else if (this.colorType == PbmColorType.Grayscale)
+            {
+                if (this.encoding == PbmEncoding.Plain)
+                {
+                    signature = (byte)'2';
+                }
+                else
+                {
+                    signature = (byte)'5';
+                }
+            }
+            else
+            {
+                // RGB ColorType
+                if (this.encoding == PbmEncoding.Plain)
+                {
+                    signature = (byte)'3';
+                }
+                else
+                {
+                    signature = (byte)'6';
+                }
+            }
+
+            return signature;
+        }
+
+        private void WriteHeader(Stream stream, byte signature, Size pixelSize)
+        {
+            Span<byte> buffer = stackalloc byte[128];
+
+            int written = 3;
+            buffer[0] = P;
+            buffer[1] = signature;
+            buffer[2] = NewLine;
+
+            Utf8Formatter.TryFormat(pixelSize.Width, buffer.Slice(written), out int bytesWritten);
+            written += bytesWritten;
+            buffer[written++] = Space;
+            Utf8Formatter.TryFormat(pixelSize.Height, buffer.Slice(written), out bytesWritten);
+            written += bytesWritten;
+            buffer[written++] = NewLine;
+
+            if (this.colorType != PbmColorType.BlackAndWhite)
+            {
+                int maxPixelValue = this.componentType == PbmComponentType.Short ? 65535 : 255;
+                Utf8Formatter.TryFormat(maxPixelValue, buffer.Slice(written), out bytesWritten);
+                written += bytesWritten;
+                buffer[written++] = NewLine;
+            }
+
+            stream.Write(buffer, 0, written);
+        }
+
+        /// <summary>
+        /// Writes the pixel data to the binary stream.
+        /// </summary>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
+        /// <param name="stream">The <see cref="Stream"/> to write to.</param>
+        /// <param name="image">
+        /// The <see cref="ImageFrame{TPixel}"/> containing pixel data.
+        /// </param>
+        private void WritePixels<TPixel>(Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            if (this.encoding == PbmEncoding.Plain)
+            {
+                PlainEncoder.WritePixels(this.configuration, stream, image, this.colorType, this.componentType);
+            }
+            else
+            {
+                BinaryEncoder.WritePixels(this.configuration, stream, image, this.colorType, this.componentType);
+            }
+        }
+    }
+}

src/ImageSharp/Formats/Pbm/PbmEncoding.cs

@@ -0,0 +1,21 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Provides enumeration of available PBM encodings.
+    /// </summary>
+    public enum PbmEncoding : byte
+    {
+        /// <summary>
+        /// Plain text decimal encoding.
+        /// </summary>
+        Plain = 0,
+
+        /// <summary>
+        /// Binary integer encoding.
+        /// </summary>
+        Binary = 1,
+    }
+}

src/ImageSharp/Formats/Pbm/PbmFormat.cs

@@ -0,0 +1,37 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.Collections.Generic;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Registers the image encoders, decoders and mime type detectors for the PBM format.
+    /// </summary>
+    public sealed class PbmFormat : IImageFormat<PbmMetadata>
+    {
+        private PbmFormat()
+        {
+        }
+
+        /// <summary>
+        /// Gets the current instance.
+        /// </summary>
+        public static PbmFormat Instance { get; } = new();
+
+        /// <inheritdoc/>
+        public string Name => "PBM";
+
+        /// <inheritdoc/>
+        public string DefaultMimeType => "image/x-portable-pixmap";
+
+        /// <inheritdoc/>
+        public IEnumerable<string> MimeTypes => PbmConstants.MimeTypes;
+
+        /// <inheritdoc/>
+        public IEnumerable<string> FileExtensions => PbmConstants.FileExtensions;
+
+        /// <inheritdoc/>
+        public PbmMetadata CreateDefaultFormatMetadata() => new();
+    }
+}

src/ImageSharp/Formats/Pbm/PbmImageFormatDetector.cs

@@ -0,0 +1,36 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Detects Pbm file headers.
+    /// </summary>
+    public sealed class PbmImageFormatDetector : IImageFormatDetector
+    {
+        private const byte P = (byte)'P';
+        private const byte Zero = (byte)'0';
+        private const byte Seven = (byte)'7';
+
+        /// <inheritdoc/>
+        public int HeaderSize => 2;
+
+        /// <inheritdoc/>
+        public IImageFormat DetectFormat(ReadOnlySpan<byte> header) => this.IsSupportedFileFormat(header) ? PbmFormat.Instance : null;
+
+        private bool IsSupportedFileFormat(ReadOnlySpan<byte> header)
+        {
+#pragma warning disable SA1131 // Use readable conditions
+            if (1 < (uint)header.Length)
+#pragma warning restore SA1131 // Use readable conditions
+            {
+                // Signature should be between P1 and P6.
+                return header[0] == P && (uint)(header[1] - Zero - 1) < (Seven - Zero - 1);
+            }
+
+            return false;
+        }
+    }
+}

src/ImageSharp/Formats/Pbm/PbmMetadata.cs

@@ -0,0 +1,46 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Provides PBM specific metadata information for the image.
+    /// </summary>
+    public class PbmMetadata : IDeepCloneable
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PbmMetadata"/> class.
+        /// </summary>
+        public PbmMetadata() =>
+            this.ComponentType = this.ColorType == PbmColorType.BlackAndWhite ? PbmComponentType.Bit : PbmComponentType.Byte;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PbmMetadata"/> class.
+        /// </summary>
+        /// <param name="other">The metadata to create an instance from.</param>
+        private PbmMetadata(PbmMetadata other)
+        {
+            this.Encoding = other.Encoding;
+            this.ColorType = other.ColorType;
+            this.ComponentType = other.ComponentType;
+        }
+
+        /// <summary>
+        /// Gets or sets the encoding of the pixels.
+        /// </summary>
+        public PbmEncoding Encoding { get; set; } = PbmEncoding.Plain;
+
+        /// <summary>
+        /// Gets or sets the color type.
+        /// </summary>
+        public PbmColorType ColorType { get; set; } = PbmColorType.Grayscale;
+
+        /// <summary>
+        /// Gets or sets the data type of the pixel components.
+        /// </summary>
+        public PbmComponentType ComponentType { get; set; }
+
+        /// <inheritdoc/>
+        public IDeepCloneable DeepClone() => new PbmMetadata(this);
+    }
+}

src/ImageSharp/Formats/Pbm/PlainDecoder.cs

@@ -0,0 +1,198 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Buffers;
+using SixLabors.ImageSharp.IO;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Pixel decoding methods for the PBM plain encoding.
+    /// </summary>
+    internal class PlainDecoder
+    {
+        private static readonly L8 White = new(255);
+        private static readonly L8 Black = new(0);
+
+        /// <summary>
+        /// Decode the specified pixels.
+        /// </summary>
+        /// <typeparam name="TPixel">The type of pixel to encode to.</typeparam>
+        /// <param name="configuration">The configuration.</param>
+        /// <param name="pixels">The pixel array to encode into.</param>
+        /// <param name="stream">The stream to read the data from.</param>
+        /// <param name="colorType">The ColorType to decode.</param>
+        /// <param name="componentType">Data type of the pixles components.</param>
+        public static void Process<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream, PbmColorType colorType, PbmComponentType componentType)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            if (colorType == PbmColorType.Grayscale)
+            {
+                if (componentType == PbmComponentType.Byte)
+                {
+                    ProcessGrayscale(configuration, pixels, stream);
+                }
+                else
+                {
+                    ProcessWideGrayscale(configuration, pixels, stream);
+                }
+            }
+            else if (colorType == PbmColorType.Rgb)
+            {
+                if (componentType == PbmComponentType.Byte)
+                {
+                    ProcessRgb(configuration, pixels, stream);
+                }
+                else
+                {
+                    ProcessWideRgb(configuration, pixels, stream);
+                }
+            }
+            else
+            {
+                ProcessBlackAndWhite(configuration, pixels, stream);
+            }
+        }
+
+        private static void ProcessGrayscale<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = pixels.Width;
+            int height = pixels.Height;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<L8> row = allocator.Allocate<L8>(width);
+            Span<L8> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                for (int x = 0; x < width; x++)
+                {
+                    byte value = (byte)stream.ReadDecimal();
+                    stream.SkipWhitespaceAndComments();
+                    rowSpan[x] = new L8(value);
+                }
+
+                Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.FromL8(
+                    configuration,
+                    rowSpan,
+                    pixelSpan);
+            }
+        }
+
+        private static void ProcessWideGrayscale<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = pixels.Width;
+            int height = pixels.Height;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<L16> row = allocator.Allocate<L16>(width);
+            Span<L16> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                for (int x = 0; x < width; x++)
+                {
+                    ushort value = (ushort)stream.ReadDecimal();
+                    stream.SkipWhitespaceAndComments();
+                    rowSpan[x] = new L16(value);
+                }
+
+                Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.FromL16(
+                    configuration,
+                    rowSpan,
+                    pixelSpan);
+            }
+        }
+
+        private static void ProcessRgb<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = pixels.Width;
+            int height = pixels.Height;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<Rgb24> row = allocator.Allocate<Rgb24>(width);
+            Span<Rgb24> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                for (int x = 0; x < width; x++)
+                {
+                    byte red = (byte)stream.ReadDecimal();
+                    stream.SkipWhitespaceAndComments();
+                    byte green = (byte)stream.ReadDecimal();
+                    stream.SkipWhitespaceAndComments();
+                    byte blue = (byte)stream.ReadDecimal();
+                    stream.SkipWhitespaceAndComments();
+                    rowSpan[x] = new Rgb24(red, green, blue);
+                }
+
+                Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.FromRgb24(
+                    configuration,
+                    rowSpan,
+                    pixelSpan);
+            }
+        }
+
+        private static void ProcessWideRgb<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = pixels.Width;
+            int height = pixels.Height;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<Rgb48> row = allocator.Allocate<Rgb48>(width);
+            Span<Rgb48> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                for (int x = 0; x < width; x++)
+                {
+                    ushort red = (ushort)stream.ReadDecimal();
+                    stream.SkipWhitespaceAndComments();
+                    ushort green = (ushort)stream.ReadDecimal();
+                    stream.SkipWhitespaceAndComments();
+                    ushort blue = (ushort)stream.ReadDecimal();
+                    stream.SkipWhitespaceAndComments();
+                    rowSpan[x] = new Rgb48(red, green, blue);
+                }
+
+                Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.FromRgb48(
+                    configuration,
+                    rowSpan,
+                    pixelSpan);
+            }
+        }
+
+        private static void ProcessBlackAndWhite<TPixel>(Configuration configuration, Buffer2D<TPixel> pixels, BufferedReadStream stream)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = pixels.Width;
+            int height = pixels.Height;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<L8> row = allocator.Allocate<L8>(width);
+            Span<L8> rowSpan = row.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                for (int x = 0; x < width; x++)
+                {
+                    int value = stream.ReadDecimal();
+                    stream.SkipWhitespaceAndComments();
+                    rowSpan[x] = value == 0 ? White : Black;
+                }
+
+                Span<TPixel> pixelSpan = pixels.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.FromL8(
+                    configuration,
+                    rowSpan,
+                    pixelSpan);
+            }
+        }
+    }
+}

src/ImageSharp/Formats/Pbm/PlainEncoder.cs

@@ -0,0 +1,251 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Buffers;
+using System.Buffers.Text;
+using System.IO;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Pbm
+{
+    /// <summary>
+    /// Pixel encoding methods for the PBM plain encoding.
+    /// </summary>
+    internal class PlainEncoder
+    {
+        private const byte NewLine = 0x0a;
+        private const byte Space = 0x20;
+        private const byte Zero = 0x30;
+        private const byte One = 0x31;
+
+        private const int MaxCharsPerPixelBlackAndWhite = 2;
+        private const int MaxCharsPerPixelGrayscale = 4;
+        private const int MaxCharsPerPixelGrayscaleWide = 6;
+        private const int MaxCharsPerPixelRgb = 4 * 3;
+        private const int MaxCharsPerPixelRgbWide = 6 * 3;
+
+        private static readonly StandardFormat DecimalFormat = StandardFormat.Parse("D");
+
+        /// <summary>
+        /// Decode pixels into the PBM plain encoding.
+        /// </summary>
+        /// <typeparam name="TPixel">The type of input pixel.</typeparam>
+        /// <param name="configuration">The configuration.</param>
+        /// <param name="stream">The bytestream to write to.</param>
+        /// <param name="image">The input image.</param>
+        /// <param name="colorType">The ColorType to use.</param>
+        /// <param name="componentType">Data type of the pixles components.</param>
+        public static void WritePixels<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image, PbmColorType colorType, PbmComponentType componentType)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            if (colorType == PbmColorType.Grayscale)
+            {
+                if (componentType == PbmComponentType.Byte)
+                {
+                    WriteGrayscale(configuration, stream, image);
+                }
+                else
+                {
+                    WriteWideGrayscale(configuration, stream, image);
+                }
+            }
+            else if (colorType == PbmColorType.Rgb)
+            {
+                if (componentType == PbmComponentType.Byte)
+                {
+                    WriteRgb(configuration, stream, image);
+                }
+                else
+                {
+                    WriteWideRgb(configuration, stream, image);
+                }
+            }
+            else
+            {
+                WriteBlackAndWhite(configuration, stream, image);
+            }
+
+            // Write EOF indicator, as some encoders expect it.
+            stream.WriteByte(Space);
+        }
+
+        private static void WriteGrayscale<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = image.Width;
+            int height = image.Height;
+            Buffer2D<TPixel> pixelBuffer = image.PixelBuffer;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<L8> row = allocator.Allocate<L8>(width);
+            Span<L8> rowSpan = row.GetSpan();
+            using IMemoryOwner<byte> plainMemory = allocator.Allocate<byte>(width * MaxCharsPerPixelGrayscale);
+            Span<byte> plainSpan = plainMemory.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.ToL8(
+                    configuration,
+                    pixelSpan,
+                    rowSpan);
+
+                int written = 0;
+                for (int x = 0; x < width; x++)
+                {
+                    Utf8Formatter.TryFormat(rowSpan[x].PackedValue, plainSpan.Slice(written), out int bytesWritten, DecimalFormat);
+                    written += bytesWritten;
+                    plainSpan[written++] = Space;
+                }
+
+                plainSpan[written - 1] = NewLine;
+                stream.Write(plainSpan, 0, written);
+            }
+        }
+
+        private static void WriteWideGrayscale<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = image.Width;
+            int height = image.Height;
+            Buffer2D<TPixel> pixelBuffer = image.PixelBuffer;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<L16> row = allocator.Allocate<L16>(width);
+            Span<L16> rowSpan = row.GetSpan();
+            using IMemoryOwner<byte> plainMemory = allocator.Allocate<byte>(width * MaxCharsPerPixelGrayscaleWide);
+            Span<byte> plainSpan = plainMemory.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.ToL16(
+                    configuration,
+                    pixelSpan,
+                    rowSpan);
+
+                int written = 0;
+                for (int x = 0; x < width; x++)
+                {
+                    Utf8Formatter.TryFormat(rowSpan[x].PackedValue, plainSpan.Slice(written), out int bytesWritten, DecimalFormat);
+                    written += bytesWritten;
+                    plainSpan[written++] = Space;
+                }
+
+                plainSpan[written - 1] = NewLine;
+                stream.Write(plainSpan, 0, written);
+            }
+        }
+
+        private static void WriteRgb<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = image.Width;
+            int height = image.Height;
+            Buffer2D<TPixel> pixelBuffer = image.PixelBuffer;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<Rgb24> row = allocator.Allocate<Rgb24>(width);
+            Span<Rgb24> rowSpan = row.GetSpan();
+            using IMemoryOwner<byte> plainMemory = allocator.Allocate<byte>(width * MaxCharsPerPixelRgb);
+            Span<byte> plainSpan = plainMemory.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.ToRgb24(
+                    configuration,
+                    pixelSpan,
+                    rowSpan);
+
+                int written = 0;
+                for (int x = 0; x < width; x++)
+                {
+                    Utf8Formatter.TryFormat(rowSpan[x].R, plainSpan.Slice(written), out int bytesWritten, DecimalFormat);
+                    written += bytesWritten;
+                    plainSpan[written++] = Space;
+                    Utf8Formatter.TryFormat(rowSpan[x].G, plainSpan.Slice(written), out bytesWritten, DecimalFormat);
+                    written += bytesWritten;
+                    plainSpan[written++] = Space;
+                    Utf8Formatter.TryFormat(rowSpan[x].B, plainSpan.Slice(written), out bytesWritten, DecimalFormat);
+                    written += bytesWritten;
+                    plainSpan[written++] = Space;
+                }
+
+                plainSpan[written - 1] = NewLine;
+                stream.Write(plainSpan, 0, written);
+            }
+        }
+
+        private static void WriteWideRgb<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = image.Width;
+            int height = image.Height;
+            Buffer2D<TPixel> pixelBuffer = image.PixelBuffer;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<Rgb48> row = allocator.Allocate<Rgb48>(width);
+            Span<Rgb48> rowSpan = row.GetSpan();
+            using IMemoryOwner<byte> plainMemory = allocator.Allocate<byte>(width * MaxCharsPerPixelRgbWide);
+            Span<byte> plainSpan = plainMemory.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.ToRgb48(
+                    configuration,
+                    pixelSpan,
+                    rowSpan);
+
+                int written = 0;
+                for (int x = 0; x < width; x++)
+                {
+                    Utf8Formatter.TryFormat(rowSpan[x].R, plainSpan.Slice(written), out int bytesWritten, DecimalFormat);
+                    written += bytesWritten;
+                    plainSpan[written++] = Space;
+                    Utf8Formatter.TryFormat(rowSpan[x].G, plainSpan.Slice(written), out bytesWritten, DecimalFormat);
+                    written += bytesWritten;
+                    plainSpan[written++] = Space;
+                    Utf8Formatter.TryFormat(rowSpan[x].B, plainSpan.Slice(written), out bytesWritten, DecimalFormat);
+                    written += bytesWritten;
+                    plainSpan[written++] = Space;
+                }
+
+                plainSpan[written - 1] = NewLine;
+                stream.Write(plainSpan, 0, written);
+            }
+        }
+
+        private static void WriteBlackAndWhite<TPixel>(Configuration configuration, Stream stream, ImageFrame<TPixel> image)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            int width = image.Width;
+            int height = image.Height;
+            Buffer2D<TPixel> pixelBuffer = image.PixelBuffer;
+            MemoryAllocator allocator = configuration.MemoryAllocator;
+            using IMemoryOwner<L8> row = allocator.Allocate<L8>(width);
+            Span<L8> rowSpan = row.GetSpan();
+            using IMemoryOwner<byte> plainMemory = allocator.Allocate<byte>(width * MaxCharsPerPixelBlackAndWhite);
+            Span<byte> plainSpan = plainMemory.GetSpan();
+
+            for (int y = 0; y < height; y++)
+            {
+                Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
+                PixelOperations<TPixel>.Instance.ToL8(
+                    configuration,
+                    pixelSpan,
+                    rowSpan);
+
+                int written = 0;
+                for (int x = 0; x < width; x++)
+                {
+                    byte value = (rowSpan[x].PackedValue < 128) ? One : Zero;
+                    plainSpan[written++] = value;
+                    plainSpan[written++] = Space;
+                }
+
+                plainSpan[written - 1] = NewLine;
+                stream.Write(plainSpan, 0, written);
+            }
+        }
+    }
+}

src/ImageSharp/ImageSharp.csproj

@@ -10,7 +10,7 @@
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <RepositoryUrl Condition="'$(RepositoryUrl)' == ''">https://github.com/SixLabors/ImageSharp/</RepositoryUrl>
     <PackageProjectUrl>$(RepositoryUrl)</PackageProjectUrl>
-    <PackageTags>Image Resize Crop Gif Jpg Jpeg Bitmap Png Tga NetCore</PackageTags>
+    <PackageTags>Image Resize Crop Gif Jpg Jpeg Bitmap Pbm Png Tga NetCore</PackageTags>
     <Description>A new, fully featured, fully managed, cross-platform, 2D graphics API for .NET</Description>
     <Configurations>Debug;Release;Debug-InnerLoop;Release-InnerLoop</Configurations>
   </PropertyGroup>

tests/ImageSharp.Tests/ConfigurationTests.cs

@@ -23,7 +23,7 @@ namespace SixLabors.ImageSharp.Tests
 
         public Configuration DefaultConfiguration { get; }
 
-        private readonly int expectedDefaultConfigurationCount = 7;
+        private readonly int expectedDefaultConfigurationCount = 8;
 
         public ConfigurationTests()
         {

tests/ImageSharp.Tests/Formats/GeneralFormatTests.cs

@@ -134,6 +134,11 @@ namespace SixLabors.ImageSharp.Tests.Formats
                         image.SaveAsJpeg(output);
                     }
 
+                    using (FileStream output = File.OpenWrite(Path.Combine(path, $"{file.FileNameWithoutExtension}.pbm")))
+                    {
+                        image.SaveAsPbm(output);
+                    }
+
                     using (FileStream output = File.OpenWrite(Path.Combine(path, $"{file.FileNameWithoutExtension}.png")))
                     {
                         image.SaveAsPng(output);
@@ -181,6 +186,10 @@ namespace SixLabors.ImageSharp.Tests.Formats
         }
 
         [Theory]
+        [InlineData(10, 10, "pbm")]
+        [InlineData(100, 100, "pbm")]
+        [InlineData(100, 10, "pbm")]
+        [InlineData(10, 100, "pbm")]
         [InlineData(10, 10, "png")]
         [InlineData(100, 100, "png")]
         [InlineData(100, 10, "png")]

tests/ImageSharp.Tests/Formats/ImageFormatManagerTests.cs

@@ -9,6 +9,7 @@ using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Bmp;
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Formats.Pbm;
 using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Formats.Tga;
 using SixLabors.ImageSharp.Formats.Tiff;
@@ -33,6 +34,7 @@ namespace SixLabors.ImageSharp.Tests.Formats
         [Fact]
         public void IfAutoLoadWellKnownFormatsIsTrueAllFormatsAreLoaded()
         {
+            Assert.Equal(1, this.DefaultFormatsManager.ImageEncoders.Select(item => item.Value).OfType<PbmEncoder>().Count());
             Assert.Equal(1, this.DefaultFormatsManager.ImageEncoders.Select(item => item.Value).OfType<PngEncoder>().Count());
             Assert.Equal(1, this.DefaultFormatsManager.ImageEncoders.Select(item => item.Value).OfType<BmpEncoder>().Count());
             Assert.Equal(1, this.DefaultFormatsManager.ImageEncoders.Select(item => item.Value).OfType<JpegEncoder>().Count());
@@ -41,6 +43,7 @@ namespace SixLabors.ImageSharp.Tests.Formats
             Assert.Equal(1, this.DefaultFormatsManager.ImageEncoders.Select(item => item.Value).OfType<TiffEncoder>().Count());
             Assert.Equal(1, this.DefaultFormatsManager.ImageEncoders.Select(item => item.Value).OfType<WebpEncoder>().Count());
 
+            Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<PbmDecoder>().Count());
             Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<PngDecoder>().Count());
             Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<BmpDecoder>().Count());
             Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<JpegDecoder>().Count());

tests/ImageSharp.Tests/Formats/Pbm/ImageExtensionsTest.cs

@@ -0,0 +1,155 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.IO;
+using System.Threading.Tasks;
+using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Formats.Pbm;
+using SixLabors.ImageSharp.PixelFormats;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Tests.Formats.Pbm
+{
+    public class ImageExtensionsTest
+    {
+        [Fact]
+        public void SaveAsPbm_Path()
+        {
+            string dir = TestEnvironment.CreateOutputDirectory(nameof(ImageExtensionsTest));
+            string file = Path.Combine(dir, "SaveAsPbm_Path.pbm");
+
+            using (var image = new Image<L8>(10, 10))
+            {
+                image.SaveAsPbm(file);
+            }
+
+            using (Image.Load(file, out IImageFormat mime))
+            {
+                Assert.Equal("image/x-portable-pixmap", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public async Task SaveAsPbmAsync_Path()
+        {
+            string dir = TestEnvironment.CreateOutputDirectory(nameof(ImageExtensionsTest));
+            string file = Path.Combine(dir, "SaveAsPbmAsync_Path.pbm");
+
+            using (var image = new Image<L8>(10, 10))
+            {
+                await image.SaveAsPbmAsync(file);
+            }
+
+            using (Image.Load(file, out IImageFormat mime))
+            {
+                Assert.Equal("image/x-portable-pixmap", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public void SaveAsPbm_Path_Encoder()
+        {
+            string dir = TestEnvironment.CreateOutputDirectory(nameof(ImageExtensions));
+            string file = Path.Combine(dir, "SaveAsPbm_Path_Encoder.pbm");
+
+            using (var image = new Image<L8>(10, 10))
+            {
+                image.SaveAsPbm(file, new PbmEncoder());
+            }
+
+            using (Image.Load(file, out IImageFormat mime))
+            {
+                Assert.Equal("image/x-portable-pixmap", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public async Task SaveAsPbmAsync_Path_Encoder()
+        {
+            string dir = TestEnvironment.CreateOutputDirectory(nameof(ImageExtensions));
+            string file = Path.Combine(dir, "SaveAsPbmAsync_Path_Encoder.pbm");
+
+            using (var image = new Image<L8>(10, 10))
+            {
+                await image.SaveAsPbmAsync(file, new PbmEncoder());
+            }
+
+            using (Image.Load(file, out IImageFormat mime))
+            {
+                Assert.Equal("image/x-portable-pixmap", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public void SaveAsPbm_Stream()
+        {
+            using var memoryStream = new MemoryStream();
+
+            using (var image = new Image<L8>(10, 10))
+            {
+                image.SaveAsPbm(memoryStream);
+            }
+
+            memoryStream.Position = 0;
+
+            using (Image.Load(memoryStream, out IImageFormat mime))
+            {
+                Assert.Equal("image/x-portable-pixmap", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public async Task SaveAsPbmAsync_StreamAsync()
+        {
+            using var memoryStream = new MemoryStream();
+
+            using (var image = new Image<L8>(10, 10))
+            {
+                await image.SaveAsPbmAsync(memoryStream);
+            }
+
+            memoryStream.Position = 0;
+
+            using (Image.Load(memoryStream, out IImageFormat mime))
+            {
+                Assert.Equal("image/x-portable-pixmap", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public void SaveAsPbm_Stream_Encoder()
+        {
+            using var memoryStream = new MemoryStream();
+
+            using (var image = new Image<L8>(10, 10))
+            {
+                image.SaveAsPbm(memoryStream, new PbmEncoder());
+            }
+
+            memoryStream.Position = 0;
+
+            using (Image.Load(memoryStream, out IImageFormat mime))
+            {
+                Assert.Equal("image/x-portable-pixmap", mime.DefaultMimeType);
+            }
+        }
+
+        [Fact]
+        public async Task SaveAsPbmAsync_Stream_Encoder()
+        {
+            using var memoryStream = new MemoryStream();
+
+            using (var image = new Image<L8>(10, 10))
+            {
+                await image.SaveAsPbmAsync(memoryStream, new PbmEncoder());
+            }
+
+            memoryStream.Position = 0;
+
+            using (Image.Load(memoryStream, out IImageFormat mime))
+            {
+                Assert.Equal("image/x-portable-pixmap", mime.DefaultMimeType);
+            }
+        }
+    }
+}

tests/ImageSharp.Tests/Formats/Pbm/PbmDecoderTests.cs

@@ -0,0 +1,100 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.IO;
+using SixLabors.ImageSharp.Formats.Pbm;
+using SixLabors.ImageSharp.PixelFormats;
+using Xunit;
+using static SixLabors.ImageSharp.Tests.TestImages.Pbm;
+
+// ReSharper disable InconsistentNaming
+namespace SixLabors.ImageSharp.Tests.Formats.Pbm
+{
+    [Trait("Format", "Pbm")]
+    public class PbmDecoderTests
+    {
+        [Theory]
+        [InlineData(BlackAndWhitePlain, PbmColorType.BlackAndWhite, PbmComponentType.Bit)]
+        [InlineData(BlackAndWhiteBinary, PbmColorType.BlackAndWhite, PbmComponentType.Bit)]
+        [InlineData(GrayscalePlain, PbmColorType.Grayscale, PbmComponentType.Byte)]
+        [InlineData(GrayscalePlainMagick, PbmColorType.Grayscale, PbmComponentType.Byte)]
+        [InlineData(GrayscaleBinary, PbmColorType.Grayscale, PbmComponentType.Byte)]
+        [InlineData(GrayscaleBinaryWide, PbmColorType.Grayscale, PbmComponentType.Short)]
+        [InlineData(RgbPlain, PbmColorType.Rgb, PbmComponentType.Byte)]
+        [InlineData(RgbPlainMagick, PbmColorType.Rgb, PbmComponentType.Byte)]
+        [InlineData(RgbBinary, PbmColorType.Rgb, PbmComponentType.Byte)]
+        public void ImageLoadCanDecode(string imagePath, PbmColorType expectedColorType, PbmComponentType expectedComponentType)
+        {
+            // Arrange
+            var testFile = TestFile.Create(imagePath);
+            using var stream = new MemoryStream(testFile.Bytes, false);
+
+            // Act
+            using var image = Image.Load(stream);
+
+            // Assert
+            Assert.NotNull(image);
+            PbmMetadata metadata = image.Metadata.GetPbmMetadata();
+            Assert.NotNull(metadata);
+            Assert.Equal(expectedColorType, metadata.ColorType);
+            Assert.Equal(expectedComponentType, metadata.ComponentType);
+        }
+
+        [Theory]
+        [InlineData(BlackAndWhitePlain)]
+        [InlineData(BlackAndWhiteBinary)]
+        [InlineData(GrayscalePlain)]
+        [InlineData(GrayscalePlainMagick)]
+        [InlineData(GrayscaleBinary)]
+        [InlineData(GrayscaleBinaryWide)]
+        public void ImageLoadL8CanDecode(string imagePath)
+        {
+            // Arrange
+            var testFile = TestFile.Create(imagePath);
+            using var stream = new MemoryStream(testFile.Bytes, false);
+
+            // Act
+            using var image = Image.Load<L8>(stream);
+
+            // Assert
+            Assert.NotNull(image);
+        }
+
+        [Theory]
+        [InlineData(RgbPlain)]
+        [InlineData(RgbPlainMagick)]
+        [InlineData(RgbBinary)]
+        public void ImageLoadRgb24CanDecode(string imagePath)
+        {
+            // Arrange
+            var testFile = TestFile.Create(imagePath);
+            using var stream = new MemoryStream(testFile.Bytes, false);
+
+            // Act
+            using var image = Image.Load<Rgb24>(stream);
+
+            // Assert
+            Assert.NotNull(image);
+        }
+
+        [Theory]
+        [WithFile(BlackAndWhitePlain, PixelTypes.L8, "pbm")]
+        [WithFile(BlackAndWhiteBinary, PixelTypes.L8, "pbm")]
+        [WithFile(GrayscalePlain, PixelTypes.L8, "pgm")]
+        [WithFile(GrayscalePlainNormalized, PixelTypes.L8, "pgm")]
+        [WithFile(GrayscaleBinary, PixelTypes.L8, "pgm")]
+        [WithFile(GrayscaleBinaryWide, PixelTypes.L16, "pgm")]
+        [WithFile(RgbPlain, PixelTypes.Rgb24, "ppm")]
+        [WithFile(RgbPlainNormalized, PixelTypes.Rgb24, "ppm")]
+        [WithFile(RgbBinary, PixelTypes.Rgb24, "ppm")]
+        public void DecodeReferenceImage<TPixel>(TestImageProvider<TPixel> provider, string extension)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            using Image<TPixel> image = provider.GetImage();
+            image.DebugSave(provider, extension: extension);
+
+            bool isGrayscale = extension is "pgm" or "pbm";
+            image.CompareToReferenceOutput(provider, grayscale: isGrayscale);
+        }
+    }
+}

tests/ImageSharp.Tests/Formats/Pbm/PbmEncoderTests.cs

@@ -0,0 +1,145 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.IO;
+using SixLabors.ImageSharp.Formats.Pbm;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
+using Xunit;
+using static SixLabors.ImageSharp.Tests.TestImages.Pbm;
+
+// ReSharper disable InconsistentNaming
+namespace SixLabors.ImageSharp.Tests.Formats.Pbm
+{
+    [Collection("RunSerial")]
+    [Trait("Format", "Pbm")]
+    public class PbmEncoderTests
+    {
+        public static readonly TheoryData<PbmColorType> ColorType =
+            new()
+            {
+                PbmColorType.BlackAndWhite,
+                PbmColorType.Grayscale,
+                PbmColorType.Rgb
+            };
+
+        public static readonly TheoryData<string, PbmColorType> PbmColorTypeFiles =
+            new()
+            {
+                { BlackAndWhiteBinary, PbmColorType.BlackAndWhite },
+                { BlackAndWhitePlain, PbmColorType.BlackAndWhite },
+                { GrayscaleBinary, PbmColorType.Grayscale },
+                { GrayscaleBinaryWide, PbmColorType.Grayscale },
+                { GrayscalePlain, PbmColorType.Grayscale },
+                { RgbBinary, PbmColorType.Rgb },
+                { RgbPlain, PbmColorType.Rgb },
+            };
+
+        [Theory]
+        [MemberData(nameof(PbmColorTypeFiles))]
+        public void PbmEncoder_PreserveColorType(string imagePath, PbmColorType pbmColorType)
+        {
+            var options = new PbmEncoder();
+
+            var testFile = TestFile.Create(imagePath);
+            using (Image<Rgba32> input = testFile.CreateRgba32Image())
+            {
+                using (var memStream = new MemoryStream())
+                {
+                    input.Save(memStream, options);
+                    memStream.Position = 0;
+                    using (var output = Image.Load<Rgba32>(memStream))
+                    {
+                        PbmMetadata meta = output.Metadata.GetPbmMetadata();
+                        Assert.Equal(pbmColorType, meta.ColorType);
+                    }
+                }
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(PbmColorTypeFiles))]
+        public void PbmEncoder_WithPlainEncoding_PreserveBitsPerPixel(string imagePath, PbmColorType pbmColorType)
+        {
+            var options = new PbmEncoder()
+            {
+                Encoding = PbmEncoding.Plain
+            };
+
+            var testFile = TestFile.Create(imagePath);
+            using (Image<Rgba32> input = testFile.CreateRgba32Image())
+            {
+                using (var memStream = new MemoryStream())
+                {
+                    input.Save(memStream, options);
+
+                    // EOF indicator for plain is a Space.
+                    memStream.Seek(-1, SeekOrigin.End);
+                    int lastByte = memStream.ReadByte();
+                    Assert.Equal(0x20, lastByte);
+
+                    memStream.Seek(0, SeekOrigin.Begin);
+                    using (var output = Image.Load<Rgba32>(memStream))
+                    {
+                        PbmMetadata meta = output.Metadata.GetPbmMetadata();
+                        Assert.Equal(pbmColorType, meta.ColorType);
+                    }
+                }
+            }
+        }
+
+        [Theory]
+        [WithFile(BlackAndWhitePlain, PixelTypes.Rgb24)]
+        public void PbmEncoder_P1_Works<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : unmanaged, IPixel<TPixel> => TestPbmEncoderCore(provider, PbmColorType.BlackAndWhite, PbmEncoding.Plain);
+
+        [Theory]
+        [WithFile(BlackAndWhiteBinary, PixelTypes.Rgb24)]
+        public void PbmEncoder_P4_Works<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : unmanaged, IPixel<TPixel> => TestPbmEncoderCore(provider, PbmColorType.BlackAndWhite, PbmEncoding.Binary);
+
+        [Theory]
+        [WithFile(GrayscalePlainMagick, PixelTypes.Rgb24)]
+        public void PbmEncoder_P2_Works<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : unmanaged, IPixel<TPixel> => TestPbmEncoderCore(provider, PbmColorType.Grayscale, PbmEncoding.Plain);
+
+        [Theory]
+        [WithFile(GrayscaleBinary, PixelTypes.Rgb24)]
+        public void PbmEncoder_P5_Works<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : unmanaged, IPixel<TPixel> => TestPbmEncoderCore(provider, PbmColorType.Grayscale, PbmEncoding.Binary);
+
+        [Theory]
+        [WithFile(RgbPlainMagick, PixelTypes.Rgb24)]
+        public void PbmEncoder_P3_Works<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : unmanaged, IPixel<TPixel> => TestPbmEncoderCore(provider, PbmColorType.Rgb, PbmEncoding.Plain);
+
+        [Theory]
+        [WithFile(RgbBinary, PixelTypes.Rgb24)]
+        public void PbmEncoder_P6_Works<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : unmanaged, IPixel<TPixel> => TestPbmEncoderCore(provider, PbmColorType.Rgb, PbmEncoding.Binary);
+
+        private static void TestPbmEncoderCore<TPixel>(
+            TestImageProvider<TPixel> provider,
+            PbmColorType colorType,
+            PbmEncoding encoding,
+            bool useExactComparer = true,
+            float compareTolerance = 0.01f)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            using (Image<TPixel> image = provider.GetImage())
+            {
+                var encoder = new PbmEncoder { ColorType = colorType, Encoding = encoding };
+
+                using (var memStream = new MemoryStream())
+                {
+                    image.Save(memStream, encoder);
+                    memStream.Position = 0;
+                    using (var encodedImage = (Image<TPixel>)Image.Load(memStream))
+                    {
+                        ImageComparingUtils.CompareWithReferenceDecoder(provider, encodedImage, useExactComparer, compareTolerance);
+                    }
+                }
+            }
+        }
+    }
+}

tests/ImageSharp.Tests/Formats/Pbm/PbmMetadataTests.cs

@@ -0,0 +1,86 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.IO;
+using SixLabors.ImageSharp.Formats.Pbm;
+
+using Xunit;
+using static SixLabors.ImageSharp.Tests.TestImages.Pbm;
+
+// ReSharper disable InconsistentNaming
+namespace SixLabors.ImageSharp.Tests.Formats.Pbm
+{
+    [Trait("Format", "Pbm")]
+    public class PbmMetadataTests
+    {
+        [Fact]
+        public void CloneIsDeep()
+        {
+            var meta = new PbmMetadata { ColorType = PbmColorType.Grayscale };
+            var clone = (PbmMetadata)meta.DeepClone();
+
+            clone.ColorType = PbmColorType.Rgb;
+            clone.ComponentType = PbmComponentType.Short;
+
+            Assert.False(meta.ColorType.Equals(clone.ColorType));
+            Assert.False(meta.ComponentType.Equals(clone.ComponentType));
+        }
+
+        [Theory]
+        [InlineData(BlackAndWhitePlain, PbmEncoding.Plain)]
+        [InlineData(BlackAndWhiteBinary, PbmEncoding.Binary)]
+        [InlineData(GrayscaleBinary, PbmEncoding.Binary)]
+        [InlineData(GrayscaleBinaryWide, PbmEncoding.Binary)]
+        [InlineData(GrayscalePlain, PbmEncoding.Plain)]
+        [InlineData(RgbBinary, PbmEncoding.Binary)]
+        [InlineData(RgbPlain, PbmEncoding.Plain)]
+        public void Identify_DetectsCorrectEncoding(string imagePath, PbmEncoding expectedEncoding)
+        {
+            var testFile = TestFile.Create(imagePath);
+            using var stream = new MemoryStream(testFile.Bytes, false);
+            IImageInfo imageInfo = Image.Identify(stream);
+            Assert.NotNull(imageInfo);
+            PbmMetadata bitmapMetadata = imageInfo.Metadata.GetPbmMetadata();
+            Assert.NotNull(bitmapMetadata);
+            Assert.Equal(expectedEncoding, bitmapMetadata.Encoding);
+        }
+
+        [Theory]
+        [InlineData(BlackAndWhitePlain, PbmColorType.BlackAndWhite)]
+        [InlineData(BlackAndWhiteBinary, PbmColorType.BlackAndWhite)]
+        [InlineData(GrayscaleBinary, PbmColorType.Grayscale)]
+        [InlineData(GrayscaleBinaryWide, PbmColorType.Grayscale)]
+        [InlineData(GrayscalePlain, PbmColorType.Grayscale)]
+        [InlineData(RgbBinary, PbmColorType.Rgb)]
+        [InlineData(RgbPlain, PbmColorType.Rgb)]
+        public void Identify_DetectsCorrectColorType(string imagePath, PbmColorType expectedColorType)
+        {
+            var testFile = TestFile.Create(imagePath);
+            using var stream = new MemoryStream(testFile.Bytes, false);
+            IImageInfo imageInfo = Image.Identify(stream);
+            Assert.NotNull(imageInfo);
+            PbmMetadata bitmapMetadata = imageInfo.Metadata.GetPbmMetadata();
+            Assert.NotNull(bitmapMetadata);
+            Assert.Equal(expectedColorType, bitmapMetadata.ColorType);
+        }
+
+        [Theory]
+        [InlineData(BlackAndWhitePlain, PbmComponentType.Bit)]
+        [InlineData(BlackAndWhiteBinary, PbmComponentType.Bit)]
+        [InlineData(GrayscaleBinary, PbmComponentType.Byte)]
+        [InlineData(GrayscaleBinaryWide, PbmComponentType.Short)]
+        [InlineData(GrayscalePlain, PbmComponentType.Byte)]
+        [InlineData(RgbBinary, PbmComponentType.Byte)]
+        [InlineData(RgbPlain, PbmComponentType.Byte)]
+        public void Identify_DetectsCorrectComponentType(string imagePath, PbmComponentType expectedComponentType)
+        {
+            var testFile = TestFile.Create(imagePath);
+            using var stream = new MemoryStream(testFile.Bytes, false);
+            IImageInfo imageInfo = Image.Identify(stream);
+            Assert.NotNull(imageInfo);
+            PbmMetadata bitmapMetadata = imageInfo.Metadata.GetPbmMetadata();
+            Assert.NotNull(bitmapMetadata);
+            Assert.Equal(expectedComponentType, bitmapMetadata.ComponentType);
+        }
+    }
+}

tests/ImageSharp.Tests/Formats/Pbm/PbmRoundTripTests.cs

@@ -0,0 +1,69 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.IO;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
+using Xunit;
+using static SixLabors.ImageSharp.Tests.TestImages.Pbm;
+
+// ReSharper disable InconsistentNaming
+namespace SixLabors.ImageSharp.Tests.Formats.Pbm
+{
+    [Trait("Format", "Pbm")]
+    public class PbmRoundTripTests
+    {
+        [Theory]
+        [InlineData(BlackAndWhitePlain)]
+        [InlineData(BlackAndWhiteBinary)]
+        [InlineData(GrayscalePlain)]
+        [InlineData(GrayscalePlainNormalized)]
+        [InlineData(GrayscalePlainMagick)]
+        [InlineData(GrayscaleBinary)]
+        public void PbmGrayscaleImageCanRoundTrip(string imagePath)
+        {
+            // Arrange
+            var testFile = TestFile.Create(imagePath);
+            using var stream = new MemoryStream(testFile.Bytes, false);
+
+            // Act
+            using var originalImage = Image.Load(stream);
+            using Image<Rgb24> colorImage = originalImage.CloneAs<Rgb24>();
+            using Image<Rgb24> encodedImage = this.RoundTrip(colorImage);
+
+            // Assert
+            Assert.NotNull(encodedImage);
+            ImageComparer.Exact.VerifySimilarity(colorImage, encodedImage);
+        }
+
+        [Theory]
+        [InlineData(RgbPlain)]
+        [InlineData(RgbPlainNormalized)]
+        [InlineData(RgbPlainMagick)]
+        [InlineData(RgbBinary)]
+        public void PbmColorImageCanRoundTrip(string imagePath)
+        {
+            // Arrange
+            var testFile = TestFile.Create(imagePath);
+            using var stream = new MemoryStream(testFile.Bytes, false);
+
+            // Act
+            using var originalImage = Image.Load<Rgb24>(stream);
+            using Image<Rgb24> encodedImage = this.RoundTrip(originalImage);
+
+            // Assert
+            Assert.NotNull(encodedImage);
+            ImageComparer.Exact.VerifySimilarity(originalImage, encodedImage);
+        }
+
+        private Image<TPixel> RoundTrip<TPixel>(Image<TPixel> originalImage)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            using var decodedStream = new MemoryStream();
+            originalImage.SaveAsPbm(decodedStream);
+            decodedStream.Seek(0, SeekOrigin.Begin);
+            var encodedImage = Image.Load<TPixel>(decodedStream);
+            return encodedImage;
+        }
+    }
+}

tests/ImageSharp.Tests/Formats/Tga/TgaDecoderTests.cs

@@ -29,7 +29,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -41,7 +41,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -53,7 +53,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -65,7 +65,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -77,7 +77,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -89,7 +89,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -101,7 +101,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -113,7 +113,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -245,7 +245,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -257,7 +257,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -269,7 +269,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -281,7 +281,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -293,7 +293,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -305,7 +305,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -317,7 +317,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -329,7 +329,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -341,7 +341,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -353,7 +353,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -365,7 +365,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -377,7 +377,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -389,7 +389,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -401,7 +401,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -413,7 +413,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -425,7 +425,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -437,7 +437,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -449,7 +449,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -461,7 +461,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -473,7 +473,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -485,7 +485,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -497,7 +497,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -509,7 +509,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -521,7 +521,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -533,7 +533,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -545,7 +545,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -557,7 +557,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -569,7 +569,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -581,7 +581,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -593,7 +593,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -605,7 +605,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -617,7 +617,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -629,7 +629,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -641,7 +641,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -653,7 +653,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -665,7 +665,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -677,7 +677,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -689,7 +689,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -701,7 +701,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 
@@ -714,7 +714,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             using (Image<TPixel> image = provider.GetImage(TgaDecoder))
             {
                 image.DebugSave(provider);
-                TgaTestUtils.CompareWithReferenceDecoder(provider, image);
+                ImageComparingUtils.CompareWithReferenceDecoder(provider, image);
             }
         }
 

tests/ImageSharp.Tests/Formats/Tga/TgaEncoderTests.cs

@@ -4,7 +4,7 @@
 using System.IO;
 using SixLabors.ImageSharp.Formats.Tga;
 using SixLabors.ImageSharp.PixelFormats;
-
+using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
 using Xunit;
 using static SixLabors.ImageSharp.Tests.TestImages.Tga;
 
@@ -150,7 +150,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
                     memStream.Position = 0;
                     using (var encodedImage = (Image<TPixel>)Image.Load(memStream))
                     {
-                        TgaTestUtils.CompareWithReferenceDecoder(provider, encodedImage, useExactComparer, compareTolerance);
+                        ImageComparingUtils.CompareWithReferenceDecoder(provider, encodedImage, useExactComparer, compareTolerance);
                     }
                 }
             }

tests/ImageSharp.Tests/Formats/Tiff/TiffMetadataTests.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using SixLabors.ImageSharp.Common.Helpers;
@@ -22,6 +23,13 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff
     {
         private static TiffDecoder TiffDecoder => new TiffDecoder();
 
+        private class NumberComparer : IEqualityComparer<Number>
+        {
+            public bool Equals(Number x, Number y) => x.Equals(y);
+
+            public int GetHashCode(Number obj) => obj.GetHashCode();
+        }
+
         [Fact]
         public void TiffMetadata_CloneIsDeep()
         {

tests/ImageSharp.Tests/Formats/Tiff/TiffTestUtils.cs

@@ -1,67 +0,0 @@
-// Copyright (c) Six Labors.
-// Licensed under the Apache License, Version 2.0.
-
-using System;
-using System.Collections.Generic;
-using System.IO;
-using ImageMagick;
-
-using SixLabors.ImageSharp.PixelFormats;
-using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
-
-using Xunit;
-
-namespace SixLabors.ImageSharp.Tests.Formats.Tiff
-{
-    public static class TiffTestUtils
-    {
-        public static void CompareWithReferenceDecoder<TPixel>(
-            string encodedImagePath,
-            Image<TPixel> image,
-            bool useExactComparer = true,
-            float compareTolerance = 0.01f)
-            where TPixel : unmanaged, ImageSharp.PixelFormats.IPixel<TPixel>
-        {
-            var testFile = TestFile.Create(encodedImagePath);
-            Image<Rgba32> magickImage = DecodeWithMagick<Rgba32>(new FileInfo(testFile.FullPath));
-            if (useExactComparer)
-            {
-                ImageComparer.Exact.VerifySimilarity(magickImage, image);
-            }
-            else
-            {
-                ImageComparer.Tolerant(compareTolerance).VerifySimilarity(magickImage, image);
-            }
-        }
-
-        public static Image<TPixel> DecodeWithMagick<TPixel>(FileInfo fileInfo)
-            where TPixel : unmanaged, ImageSharp.PixelFormats.IPixel<TPixel>
-        {
-            Configuration configuration = Configuration.Default.Clone();
-            configuration.PreferContiguousImageBuffers = true;
-            using var magickImage = new MagickImage(fileInfo);
-            magickImage.AutoOrient();
-            var result = new Image<TPixel>(configuration, magickImage.Width, magickImage.Height);
-
-            Assert.True(result.DangerousTryGetSinglePixelMemory(out Memory<TPixel> resultPixels));
-
-            using IUnsafePixelCollection<ushort> pixels = magickImage.GetPixelsUnsafe();
-            byte[] data = pixels.ToByteArray(PixelMapping.RGBA);
-
-            PixelOperations<TPixel>.Instance.FromRgba32Bytes(
-                configuration,
-                data,
-                resultPixels.Span,
-                resultPixels.Length);
-
-            return result;
-        }
-    }
-
-    internal class NumberComparer : IEqualityComparer<Number>
-    {
-        public bool Equals(Number x, Number y) => x.Equals(y);
-
-        public int GetHashCode(Number obj) => obj.GetHashCode();
-    }
-}

tests/ImageSharp.Tests/Image/ImageTests.SaveAsync.cs

@@ -71,6 +71,7 @@ namespace SixLabors.ImageSharp.Tests
             }
 
             [Theory]
+            [InlineData("test.pbm", "image/x-portable-pixmap")]
             [InlineData("test.png", "image/png")]
             [InlineData("test.tga", "image/tga")]
             [InlineData("test.bmp", "image/bmp")]
@@ -114,6 +115,7 @@ namespace SixLabors.ImageSharp.Tests
             }
 
             [Theory]
+            [InlineData("test.pbm")]
             [InlineData("test.png")]
             [InlineData("test.tga")]
             [InlineData("test.bmp")]

tests/ImageSharp.Tests/TestImages.cs

@@ -866,5 +866,20 @@ namespace SixLabors.ImageSharp.Tests
 
             public static readonly string[] Metadata = { SampleMetadata };
         }
+
+        public static class Pbm
+        {
+            public const string BlackAndWhitePlain = "Pbm/blackandwhite_plain.pbm";
+            public const string BlackAndWhiteBinary = "Pbm/blackandwhite_binary.pbm";
+            public const string GrayscaleBinary = "Pbm/rings.pgm";
+            public const string GrayscaleBinaryWide = "Pbm/Gene-UP WebSocket RunImageMask.pgm";
+            public const string GrayscalePlain = "Pbm/grayscale_plain.pgm";
+            public const string GrayscalePlainNormalized = "Pbm/grayscale_plain_normalized.pgm";
+            public const string GrayscalePlainMagick = "Pbm/grayscale_plain_magick.pgm";
+            public const string RgbBinary = "Pbm/00000_00000.ppm";
+            public const string RgbPlain = "Pbm/rgb_plain.ppm";
+            public const string RgbPlainNormalized = "Pbm/rgb_plain_normalized.ppm";
+            public const string RgbPlainMagick = "Pbm/rgb_plain_magick.ppm";
+        }
     }
 }

tests/ImageSharp.Tests/Formats/Tga/TgaTestUtils.cs → tests/ImageSharp.Tests/TestUtilities/ImageComparison/ImageComparingUtils.cs

@@ -8,9 +8,9 @@ using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
 using Xunit;
 
-namespace SixLabors.ImageSharp.Tests.Formats.Tga
+namespace SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison
 {
-    public static class TgaTestUtils
+    public static class ImageComparingUtils
     {
         public static void CompareWithReferenceDecoder<TPixel>(
             TestImageProvider<TPixel> provider,

tests/ImageSharp.Tests/TestUtilities/TestEnvironment.Formats.cs

@@ -7,6 +7,7 @@ using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Bmp;
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Formats.Pbm;
 using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.Formats.Tga;
 using SixLabors.ImageSharp.Formats.Tiff;
@@ -57,6 +58,7 @@ namespace SixLabors.ImageSharp.Tests
             var cfg = new Configuration(
                 new JpegConfigurationModule(),
                 new GifConfigurationModule(),
+                new PbmConfigurationModule(),
                 new TgaConfigurationModule(),
                 new WebpConfigurationModule(),
                 new TiffConfigurationModule());

tests/Images/External/ReferenceOutput/PbmDecoderTests/DecodeReferenceImage_L16_Gene-UP WebSocket RunImageMask.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:78fc668be9f82c01c277cb2560253b04a1ff74a5af4daaf19327591420a71fec
+size 4521

tests/Images/External/ReferenceOutput/PbmDecoderTests/DecodeReferenceImage_L8_blackandwhite_binary.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:1339a8170408a7bcde261617cc599587c8f25c4dc94f780976ee1638879888e9
+size 147

tests/Images/External/ReferenceOutput/PbmDecoderTests/DecodeReferenceImage_L8_blackandwhite_plain.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:82d0397f38971cf90d7c064db332093e686196e244ece1196cca2071d27f0a6f
+size 147

tests/Images/External/ReferenceOutput/PbmDecoderTests/DecodeReferenceImage_L8_grayscale_plain.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:f8e8b8a1a05e76b1eeb577373c3a6f492e356f0dd58489afded248415cec4a07
+size 145

tests/Images/External/ReferenceOutput/PbmDecoderTests/DecodeReferenceImage_L8_grayscale_plain_normalized.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:f8e8b8a1a05e76b1eeb577373c3a6f492e356f0dd58489afded248415cec4a07
+size 145

tests/Images/External/ReferenceOutput/PbmDecoderTests/DecodeReferenceImage_L8_rings.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:388c86b3dd472ef17fb911ae424b81baeeeff74c4161cf5825eab50698d54348
+size 27884

tests/Images/External/ReferenceOutput/PbmDecoderTests/DecodeReferenceImage_Rgb24_00000_00000.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:2e3fc46b9f0546941ef95be7b750fb29376a679a921f2581403882b0e76e9caf
+size 2250

tests/Images/External/ReferenceOutput/PbmDecoderTests/DecodeReferenceImage_Rgb24_rgb_plain.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c44322c4bf461acea27053057f5241afb029d9a1e66e94dcf1be6f86f7f97727
+size 152

tests/Images/External/ReferenceOutput/PbmDecoderTests/DecodeReferenceImage_Rgb24_rgb_plain_normalized.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c44322c4bf461acea27053057f5241afb029d9a1e66e94dcf1be6f86f7f97727
+size 152

tests/Images/Input/Pbm/00000_00000.ppm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:3b291c0d3a0747c7425a3445bea1de1fa7c112a183d2f78bb9fc96ec5ae9804e
+size 2623

tests/Images/Input/Pbm/Gene-UP WebSocket RunImageMask.pgm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:38c6aadba17548dbe6496de2c81c3cb719d2330499c3cf7d4237e78dec098e53
+size 614417

tests/Images/Input/Pbm/blackandwhite_binary.pbm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:0313a99c2acdd34d6ba67815d1daa25f2452bfada71a1828dbcbb3cc48a20b20
+size 48

tests/Images/Input/Pbm/blackandwhite_plain.pbm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:12ccfacadea1c97c15b6d192ee3ae3b6a1d79bdca30fddbe597390f71e86d59c
+size 367

tests/Images/Input/Pbm/grayscale_plain.pgm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:08068b4d30f19024e716176033f13f7203a45513e6ae73e79dc824509c92621a
+size 507

tests/Images/Input/Pbm/grayscale_plain_magick.pgm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:ec652ee7ea1a82d8ea2fd344670ab9aee2c2f52af86458d9991754204e1fc2bb
+size 464

tests/Images/Input/Pbm/grayscale_plain_normalized.pgm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e39342751c2a57a060a029213fd7d83cb9a72881b8b01dd6d5b0e897df5077de
+size 599

tests/Images/Input/Pbm/rgb_plain.ppm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:895cd889f6723a5357936e852308cff25b74ead01618bf8efa0f876a86dc18c1
+size 205

tests/Images/Input/Pbm/rgb_plain_magick.ppm

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
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