Decoding 16bit rgb planar now also respects byte order

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

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
-using System.Buffers.Binary;
 using SixLabors.ImageSharp.Formats.Tiff.Utils;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;

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

@@ -0,0 +1,53 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+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 all 16 bit.
+    /// </summary>
+    internal class Rgb16PlanarTiffColor<TPixel> : TiffBasePlanarColorDecoder<TPixel>
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        private readonly bool isBigEndian;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Rgb16PlanarTiffColor{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 Rgb16PlanarTiffColor(bool isBigEndian) => this.isBigEndian = isBigEndian;
+
+        /// <inheritdoc/>
+        public override void Decode(IMemoryOwner<byte>[] data, Buffer2D<TPixel> pixels, int left, int top, int width, int height)
+        {
+            var color = default(TPixel);
+
+            System.Span<byte> redData = data[0].GetSpan();
+            System.Span<byte> greenData = data[1].GetSpan();
+            System.Span<byte> blueData = data[2].GetSpan();
+
+            int offset = 0;
+            var rgba = default(Rgba64);
+            for (int y = top; y < top + height; y++)
+            {
+                for (int x = left; x < left + width; x++)
+                {
+                    ulong r = TiffUtils.ConvertToShort(redData.Slice(offset, 2), this.isBigEndian);
+                    ulong g = TiffUtils.ConvertToShort(greenData.Slice(offset, 2), this.isBigEndian);
+                    ulong b = TiffUtils.ConvertToShort(blueData.Slice(offset, 2), this.isBigEndian);
+
+                    offset += 2;
+
+                    rgba.PackedValue = r | (g << 16) | (b << 32) | (0xfffful << 48);
+                    color.FromRgba64(rgba);
+                    pixels[x, y] = color;
+                }
+            }
+        }
+    }
+}

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

@@ -12,7 +12,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
     /// <summary>
     /// Implements the 'RGB' photometric interpretation with 'Planar' layout (for all bit depths).
     /// </summary>
-    internal class RgbPlanarTiffColor<TPixel>
+    internal class RgbPlanarTiffColor<TPixel> : TiffBasePlanarColorDecoder<TPixel>
         where TPixel : unmanaged, IPixel<TPixel>
     {
         private readonly float rFactor;
@@ -47,7 +47,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
         /// <param name="top">The y-coordinate of the  top of the image block.</param>
         /// <param name="width">The width of the image block.</param>
         /// <param name="height">The height of the image block.</param>
-        public void Decode(IMemoryOwner<byte>[] data, Buffer2D<TPixel> pixels, int left, int top, int width, int height)
+        public override void Decode(IMemoryOwner<byte>[] data, Buffer2D<TPixel> pixels, int left, int top, int width, int height)
         {
             var color = default(TPixel);
 

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

@@ -0,0 +1,28 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.Buffers;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
+{
+    /// <summary>
+    /// The base class for planar color decoders.
+    /// </summary>
+    /// <typeparam name="TPixel">The pixel format.</typeparam>
+    internal abstract class TiffBasePlanarColorDecoder<TPixel>
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        /// <summary>
+        /// Decodes source raw pixel data using the current photometric interpretation.
+        /// </summary>
+        /// <param name="data">The buffers to read image data from.</param>
+        /// <param name="pixels">The image buffer to write pixels to.</param>
+        /// <param name="left">The x-coordinate of the left-hand side of the image block.</param>
+        /// <param name="top">The y-coordinate of the  top of the image block.</param>
+        /// <param name="width">The width of the image block.</param>
+        /// <param name="height">The height of the image block.</param>
+        public abstract void Decode(IMemoryOwner<byte>[] data, Buffer2D<TPixel> pixels, int left, int top, int width, int height);
+    }
+}

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

@@ -145,12 +145,17 @@ namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
             }
         }
 
-        public static RgbPlanarTiffColor<TPixel> CreatePlanar(TiffColorType colorType, TiffBitsPerSample bitsPerSample, ushort[] colorMap)
+        public static TiffBasePlanarColorDecoder<TPixel> CreatePlanar(TiffColorType colorType, TiffBitsPerSample bitsPerSample, ushort[] colorMap, ByteOrder byteOrder)
         {
             switch (colorType)
             {
                 case TiffColorType.RgbPlanar:
                     DebugGuard.IsTrue(colorMap == null, "colorMap");
+                    if (bitsPerSample.Channel0 == 16 && bitsPerSample.Channel1 == 16 && bitsPerSample.Channel2 == 16)
+                    {
+                        return new Rgb16PlanarTiffColor<TPixel>(byteOrder == ByteOrder.BigEndian);
+                    }
+
                     return new RgbPlanarTiffColor<TPixel>(bitsPerSample);
 
                 default:

src/ImageSharp/Formats/Tiff/TiffDecoderCore.cs

@@ -266,7 +266,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
 
                 using TiffBaseDecompressor decompressor = TiffDecompressorsFactory.Create(this.CompressionType, this.memoryAllocator, this.PhotometricInterpretation, frame.Width, bitsPerPixel, this.Predictor, this.FaxCompressionOptions);
 
-                RgbPlanarTiffColor<TPixel> colorDecoder = TiffColorDecoderFactory<TPixel>.CreatePlanar(this.ColorType, this.BitsPerSample, this.ColorMap);
+                TiffBasePlanarColorDecoder<TPixel> colorDecoder = TiffColorDecoderFactory<TPixel>.CreatePlanar(this.ColorType, this.BitsPerSample, this.ColorMap, this.byteOrder);
 
                 for (int i = 0; i < stripsPerPlane; i++)
                 {

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

@@ -166,6 +166,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff
         [Theory]
         [WithFile(FlowerRgb161616Contiguous, PixelTypes.Rgba32)]
         [WithFile(FlowerRgb161616Planar, PixelTypes.Rgba32)]
+        [WithFile(FlowerRgb161616PlanarLittleEndian, PixelTypes.Rgba32)]
         [WithFile(Issues1716Rgb161616BitLittleEndian, PixelTypes.Rgba32)]
         public void TiffDecoder_CanDecode_48Bit<TPixel>(TestImageProvider<TPixel> provider)
             where TPixel : unmanaged, IPixel<TPixel> => TestTiffDecoder(provider);

tests/ImageSharp.Tests/TestImages.cs

@@ -563,6 +563,7 @@ namespace SixLabors.ImageSharp.Tests
             public const string RgbPaletteDeflate = "Tiff/rgb_palette_deflate.tiff";
             public const string FlowerRgb161616Contiguous = "Tiff/flower-rgb-contig-16.tiff";
             public const string FlowerRgb161616Planar = "Tiff/flower-rgb-planar-16.tiff";
+            public const string FlowerRgb161616PlanarLittleEndian = "Tiff/flower-rgb-planar-16_lsb.tiff";
             public const string FlowerRgb141414Contiguous = "Tiff/flower-rgb-contig-14.tiff";
             public const string FlowerRgb141414Planar = "Tiff/flower-rgb-planar-14.tiff";
             public const string FlowerRgb101010Contiguous = "Tiff/flower-rgb-contig-10.tiff";

tests/Images/Input/Tiff/flower-rgb-planar-16_lsb.tiff

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:46a60552a7ff37f2c16c43e030e7180872af712f5d9c9c7673e2547049af3da9
+size 19168