Add support for decoding 24 and 32 bit tiff images

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/BlackIsZero16TiffColor{TPixel}.cs

@@ -46,7 +46,7 @@ public override void Decode(ReadOnlySpan<byte> data, Buffer2D<TPixel> pixels, in
                 {
                     for (int x = 0; x < pixelRow.Length; x++)
                     {
-                        ushort intensity = TiffUtils.ConvertToShortBigEndian(data.Slice(offset, 2));
+                        ushort intensity = TiffUtils.ConvertToUShortBigEndian(data.Slice(offset, 2));
                         offset += 2;
 
                         pixelRow[x] = TiffUtils.ColorFromL16(l16, intensity, color);

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/BlackIsZero24TiffColor{TPixel}.cs

@@ -0,0 +1,65 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using SixLabors.ImageSharp.Formats.Tiff.Utils;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
+{
+    /// <summary>
+    /// Implements the 'BlackIsZero' photometric interpretation for 24-bit grayscale images.
+    /// </summary>
+    internal class BlackIsZero24TiffColor<TPixel> : TiffBaseColorDecoder<TPixel>
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        private readonly bool isBigEndian;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="BlackIsZero24TiffColor{TPixel}" /> class.
+        /// </summary>
+        /// <param name="isBigEndian">if set to <c>true</c> decodes the pixel data as big endian, otherwise as little endian.</param>
+        public BlackIsZero24TiffColor(bool isBigEndian) => this.isBigEndian = isBigEndian;
+
+        /// <inheritdoc/>
+        public override void Decode(ReadOnlySpan<byte> data, Buffer2D<TPixel> pixels, int left, int top, int width, int height)
+        {
+            // Note: due to an issue with netcore 2.1 and default values and unpredictable behavior with those,
+            // we define our own defaults as a workaround. See: https://github.com/dotnet/runtime/issues/55623
+            var color = default(TPixel);
+            color.FromVector4(TiffUtils.Vector4Default);
+            byte[] buffer = new byte[4];
+            int bufferStartIdx = this.isBigEndian ? 1 : 0;
+
+            Span<byte> bufferSpan = buffer.AsSpan(bufferStartIdx);
+            int offset = 0;
+            for (int y = top; y < top + height; y++)
+            {
+                Span<TPixel> pixelRow = pixels.GetRowSpan(y).Slice(left, width);
+                if (this.isBigEndian)
+                {
+                    for (int x = 0; x < pixelRow.Length; x++)
+                    {
+                        data.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong intensity = TiffUtils.ConvertToUIntBigEndian(buffer);
+                        offset += 3;
+
+                        pixelRow[x] = TiffUtils.ColorScaleTo24Bit(intensity, color);
+                    }
+                }
+                else
+                {
+                    for (int x = 0; x < pixelRow.Length; x++)
+                    {
+                        data.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong intensity = TiffUtils.ConvertToUIntLittleEndian(buffer);
+                        offset += 3;
+
+                        pixelRow[x] = TiffUtils.ColorScaleTo24Bit(intensity, color);
+                    }
+                }
+            }
+        }
+    }
+}

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/BlackIsZero32TiffColor{TPixel}.cs

@@ -0,0 +1,61 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Numerics;
+using SixLabors.ImageSharp.Formats.Tiff.Utils;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
+{
+    /// <summary>
+    /// Implements the 'BlackIsZero' photometric interpretation for 32-bit grayscale images.
+    /// </summary>
+    internal class BlackIsZero32TiffColor<TPixel> : TiffBaseColorDecoder<TPixel>
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        private readonly bool isBigEndian;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="BlackIsZero32TiffColor{TPixel}" /> class.
+        /// </summary>
+        /// <param name="isBigEndian">if set to <c>true</c> decodes the pixel data as big endian, otherwise as little endian.</param>
+        public BlackIsZero32TiffColor(bool isBigEndian) => this.isBigEndian = isBigEndian;
+
+        /// <inheritdoc/>
+        public override void Decode(ReadOnlySpan<byte> data, Buffer2D<TPixel> pixels, int left, int top, int width, int height)
+        {
+            // Note: due to an issue with netcore 2.1 and default values and unpredictable behavior with those,
+            // we define our own defaults as a workaround. See: https://github.com/dotnet/runtime/issues/55623
+            var color = default(TPixel);
+            color.FromVector4(TiffUtils.Vector4Default);
+
+            int offset = 0;
+            for (int y = top; y < top + height; y++)
+            {
+                Span<TPixel> pixelRow = pixels.GetRowSpan(y).Slice(left, width);
+                if (this.isBigEndian)
+                {
+                    for (int x = 0; x < pixelRow.Length; x++)
+                    {
+                        ulong intensity = TiffUtils.ConvertToUIntBigEndian(data.Slice(offset, 4));
+                        offset += 4;
+
+                        pixelRow[x] = TiffUtils.ColorScaleTo32Bit(intensity, color);
+                    }
+                }
+                else
+                {
+                    for (int x = 0; x < pixelRow.Length; x++)
+                    {
+                        ulong intensity = TiffUtils.ConvertToUIntLittleEndian(data.Slice(offset, 4));
+                        offset += 4;
+
+                        pixelRow[x] = TiffUtils.ColorScaleTo32Bit(intensity, color);
+                    }
+                }
+            }
+        }
+    }
+}

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/Rgb161616TiffColor{TPixel}.cs

@@ -48,11 +48,11 @@ public override void Decode(ReadOnlySpan<byte> data, Buffer2D<TPixel> pixels, in
                 {
                     for (int x = 0; x < pixelRow.Length; x++)
                     {
-                        ulong r = TiffUtils.ConvertToShortBigEndian(data.Slice(offset, 2));
+                        ulong r = TiffUtils.ConvertToUShortBigEndian(data.Slice(offset, 2));
                         offset += 2;
-                        ulong g = TiffUtils.ConvertToShortBigEndian(data.Slice(offset, 2));
+                        ulong g = TiffUtils.ConvertToUShortBigEndian(data.Slice(offset, 2));
                         offset += 2;
-                        ulong b = TiffUtils.ConvertToShortBigEndian(data.Slice(offset, 2));
+                        ulong b = TiffUtils.ConvertToUShortBigEndian(data.Slice(offset, 2));
                         offset += 2;
 
                         pixelRow[x] = TiffUtils.ColorFromRgba64(rgba, r, g, b, color);

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/Rgb16PlanarTiffColor{TPixel}.cs

@@ -10,7 +10,7 @@
 namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
 {
     /// <summary>
-    /// Implements the 'RGB' photometric interpretation with 'Planar' layout for all 16 bit.
+    /// Implements the 'RGB' photometric interpretation with 'Planar' layout for each color channel with 16 bit.
     /// </summary>
     internal class Rgb16PlanarTiffColor<TPixel> : TiffBasePlanarColorDecoder<TPixel>
         where TPixel : unmanaged, IPixel<TPixel>
@@ -44,9 +44,9 @@ public override void Decode(IMemoryOwner<byte>[] data, Buffer2D<TPixel> pixels,
                 {
                     for (int x = 0; x < pixelRow.Length; x++)
                     {
-                        ulong r = TiffUtils.ConvertToShortBigEndian(redData.Slice(offset, 2));
-                        ulong g = TiffUtils.ConvertToShortBigEndian(greenData.Slice(offset, 2));
-                        ulong b = TiffUtils.ConvertToShortBigEndian(blueData.Slice(offset, 2));
+                        ulong r = TiffUtils.ConvertToUShortBigEndian(redData.Slice(offset, 2));
+                        ulong g = TiffUtils.ConvertToUShortBigEndian(greenData.Slice(offset, 2));
+                        ulong b = TiffUtils.ConvertToUShortBigEndian(blueData.Slice(offset, 2));
 
                         offset += 2;
 
@@ -57,9 +57,9 @@ public override void Decode(IMemoryOwner<byte>[] data, Buffer2D<TPixel> pixels,
                 {
                     for (int x = 0; x < pixelRow.Length; x++)
                     {
-                        ulong r = TiffUtils.ConvertToShortLittleEndian(redData.Slice(offset, 2));
-                        ulong g = TiffUtils.ConvertToShortLittleEndian(greenData.Slice(offset, 2));
-                        ulong b = TiffUtils.ConvertToShortLittleEndian(blueData.Slice(offset, 2));
+                        ulong r = TiffUtils.ConvertToUShortLittleEndian(redData.Slice(offset, 2));
+                        ulong g = TiffUtils.ConvertToUShortLittleEndian(greenData.Slice(offset, 2));
+                        ulong b = TiffUtils.ConvertToUShortLittleEndian(blueData.Slice(offset, 2));
 
                         offset += 2;
 

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/Rgb242424TiffColor{TPixel}.cs

@@ -0,0 +1,82 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using SixLabors.ImageSharp.Formats.Tiff.Utils;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
+{
+    /// <summary>
+    /// Implements the 'RGB' photometric interpretation with 24 bits for each channel.
+    /// </summary>
+    internal class Rgb242424TiffColor<TPixel> : TiffBaseColorDecoder<TPixel>
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        private readonly bool isBigEndian;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Rgb242424TiffColor{TPixel}" /> class.
+        /// </summary>
+        /// <param name="isBigEndian">if set to <c>true</c> decodes the pixel data as big endian, otherwise as little endian.</param>
+        public Rgb242424TiffColor(bool isBigEndian) => this.isBigEndian = isBigEndian;
+
+        /// <inheritdoc/>
+        public override void Decode(ReadOnlySpan<byte> data, Buffer2D<TPixel> pixels, int left, int top, int width, int height)
+        {
+            // Note: due to an issue with netcore 2.1 and default values and unpredictable behavior with those,
+            // we define our own defaults as a workaround. See: https://github.com/dotnet/runtime/issues/55623
+            var color = default(TPixel);
+            color.FromVector4(TiffUtils.Vector4Default);
+            int offset = 0;
+            byte[] buffer = new byte[4];
+            int bufferStartIdx = this.isBigEndian ? 1 : 0;
+
+            Span<byte> bufferSpan = buffer.AsSpan(bufferStartIdx);
+            for (int y = top; y < top + height; y++)
+            {
+                Span<TPixel> pixelRow = pixels.GetRowSpan(y).Slice(left, width);
+
+                if (this.isBigEndian)
+                {
+                    for (int x = 0; x < pixelRow.Length; x++)
+                    {
+                        data.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong r = TiffUtils.ConvertToUIntBigEndian(buffer);
+                        offset += 3;
+
+                        data.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong g = TiffUtils.ConvertToUIntBigEndian(buffer);
+                        offset += 3;
+
+                        data.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong b = TiffUtils.ConvertToUIntBigEndian(buffer);
+                        offset += 3;
+
+                        pixelRow[x] = TiffUtils.ColorScaleTo24Bit(r, g, b, color);
+                    }
+                }
+                else
+                {
+                    for (int x = 0; x < pixelRow.Length; x++)
+                    {
+                        data.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong r = TiffUtils.ConvertToUIntLittleEndian(buffer);
+                        offset += 3;
+
+                        data.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong g = TiffUtils.ConvertToUIntLittleEndian(buffer);
+                        offset += 3;
+
+                        data.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong b = TiffUtils.ConvertToUIntLittleEndian(buffer);
+                        offset += 3;
+
+                        pixelRow[x] = TiffUtils.ColorScaleTo24Bit(r, g, b, color);
+                    }
+                }
+            }
+        }
+    }
+}

src/ImageSharp/Formats/Tiff/PhotometricInterpretation/Rgb24PlanarTiffColor{TPixel}.cs

@@ -0,0 +1,80 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Buffers;
+using SixLabors.ImageSharp.Formats.Tiff.Utils;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
+{
+    /// <summary>
+    /// Implements the 'RGB' photometric interpretation with 'Planar' layout for each color channel with 24 bit.
+    /// </summary>
+    internal class Rgb24PlanarTiffColor<TPixel> : TiffBasePlanarColorDecoder<TPixel>
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        private readonly bool isBigEndian;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Rgb24PlanarTiffColor{TPixel}" /> class.
+        /// </summary>
+        /// <param name="isBigEndian">if set to <c>true</c> decodes the pixel data as big endian, otherwise as little endian.</param>
+        public Rgb24PlanarTiffColor(bool isBigEndian) => this.isBigEndian = isBigEndian;
+
+        /// <inheritdoc/>
+        public override void Decode(IMemoryOwner<byte>[] data, Buffer2D<TPixel> pixels, int left, int top, int width, int height)
+        {
+            // Note: due to an issue with netcore 2.1 and default values and unpredictable behavior with those,
+            // we define our own defaults as a workaround. See: https://github.com/dotnet/runtime/issues/55623
+            var color = default(TPixel);
+            color.FromVector4(TiffUtils.Vector4Default);
+            byte[] buffer = new byte[4];
+            int bufferStartIdx = this.isBigEndian ? 1 : 0;
+
+            Span<byte> redData = data[0].GetSpan();
+            Span<byte> greenData = data[1].GetSpan();
+            Span<byte> blueData = data[2].GetSpan();
+            Span<byte> bufferSpan = buffer.AsSpan(bufferStartIdx);
+
+            int offset = 0;
+            for (int y = top; y < top + height; y++)
+            {
+                Span<TPixel> pixelRow = pixels.GetRowSpan(y).Slice(left, width);
+                if (this.isBigEndian)
+                {
+                    for (int x = 0; x < pixelRow.Length; x++)
+                    {
+                        redData.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong r = TiffUtils.ConvertToUIntBigEndian(buffer);
+                        greenData.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong g = TiffUtils.ConvertToUIntBigEndian(buffer);
+                        blueData.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong b = TiffUtils.ConvertToUIntBigEndian(buffer);
+
+                        offset += 3;
+
+                        pixelRow[x] = TiffUtils.ColorScaleTo24Bit(r, g, b, color);
+                    }
+                }
+                else
+                {
+                    for (int x = 0; x < pixelRow.Length; x++)
+                    {
+                        redData.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong r = TiffUtils.ConvertToUIntLittleEndian(buffer);
+                        greenData.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong g = TiffUtils.ConvertToUIntLittleEndian(buffer);
+                        blueData.Slice(offset, 3).CopyTo(bufferSpan);
+                        ulong b = TiffUtils.ConvertToUIntLittleEndian(buffer);
+
+                        offset += 3;
+
+                        pixelRow[x] = TiffUtils.ColorScaleTo24Bit(r, g, b, color);
+                    }
+                }
+            }
+        }
+    }
+}