Added option to change the orientation of an image based on the information in the Exif profile.

Former-commit-id: ae4de1addaed801930aea365f4bc0a87d03f6e3f
Former-commit-id: bb1e39e2ef759b391e88b7f3fbfd98ea97913b3f
Former-commit-id: 97d2de47e68c5dafc524656ec3d95c1c1f72e7c2

src/ImageProcessorCore/Samplers/AutoOrient.cs

@@ -0,0 +1,84 @@
+// <copyright file="EntropyCrop.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessorCore
+{
+    using Processors;
+
+    /// <summary>
+    /// Extension methods for the <see cref="Image{T,TP}"/> type.
+    /// </summary>
+    public static partial class ImageExtensions
+    {
+        /// <summary>
+        /// Adjusts an image so that its orientation is suitable for viewing.
+        /// </summary>
+        /// <typeparam name="T">The pixel format.</typeparam>
+        /// <typeparam name="TP">The packed format. <example>long, float.</example></typeparam>
+        /// <param name="source">The image to crop.</param>
+        /// <returns>The <see cref="Image"/></returns>
+        public static Image<T, TP> AutoOrient<T, TP>(this Image<T, TP> source, ProgressEventHandler progressHandler = null)
+            where T : IPackedVector<TP>
+            where TP : struct
+        {
+            Orientation orientation = GetExifOrientation(source);
+
+            switch (orientation)
+            {
+                case Orientation.Unknown:
+                case Orientation.TopLeft:
+                default:
+                    return source;
+
+                case Orientation.TopRight:
+                    return source.Flip(FlipType.Horizontal, progressHandler);
+
+                case Orientation.BottomRight:
+                    return source.Rotate(RotateType.Rotate180, progressHandler);
+
+                case Orientation.BottomLeft:
+                    return source.Flip(FlipType.Vertical, progressHandler);
+
+                case Orientation.LeftTop:
+                    return source
+                                .Rotate(RotateType.Rotate90, progressHandler)
+                                .Flip(FlipType.Horizontal, progressHandler);
+
+                case Orientation.RightTop:
+                    return source.Rotate(RotateType.Rotate90, progressHandler);
+
+                case Orientation.RightBottom:
+                    return source
+                                .Flip(FlipType.Vertical, progressHandler)
+                                .Rotate(RotateType.Rotate270, progressHandler);
+
+                case Orientation.LeftBottom:
+                    return source.Rotate(RotateType.Rotate270, progressHandler);
+            }
+        }
+
+        private static Orientation GetExifOrientation<T, TP>(Image<T, TP> source)
+            where T : IPackedVector<TP>
+            where TP : struct
+        {
+            if (source.ExifProfile == null)
+            {
+                return Orientation.Unknown;
+            }
+
+            ExifValue value = source.ExifProfile.GetValue(ExifTag.Orientation);
+            if (value == null)
+            {
+                return Orientation.Unknown;
+            }
+
+            Orientation orientation = (Orientation)value.Value;
+
+            source.ExifProfile.SetValue(ExifTag.Orientation, (ushort)Orientation.TopLeft);
+
+            return orientation;
+        }
+    }
+}

src/ImageProcessorCore/Samplers/Options/Orientation.cs

@@ -0,0 +1,20 @@
+// <copyright file="AnchorPosition.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessorCore
+{
+    internal enum Orientation : ushort
+    {
+        Unknown = 0,
+        TopLeft = 1,
+        TopRight = 2,
+        BottomRight = 3,
+        BottomLeft = 4,
+        LeftTop = 5,
+        RightTop = 6,
+        RightBottom = 7,
+        LeftBottom = 8
+    }
+}

tests/ImageProcessorCore.Tests/Processors/Samplers/AutoOrientTests.cs

@@ -0,0 +1,60 @@
+// <copyright file="RotateFlipTest.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessorCore.Tests
+{
+    using System.IO;
+    using Xunit;
+
+    public class AutoOrientTests : FileTestBase
+    {
+        public static readonly TheoryData<RotateType, FlipType, ushort> OrientationValues
+            = new TheoryData<RotateType, FlipType, ushort>
+        {
+            { RotateType.None,      FlipType.None,       0 },
+            { RotateType.None,      FlipType.None,       1 },
+            { RotateType.None,      FlipType.Horizontal, 2 },
+            { RotateType.Rotate180, FlipType.None,       3 },
+            { RotateType.Rotate180, FlipType.Horizontal, 4 },
+            { RotateType.Rotate90,  FlipType.Horizontal, 5 },
+            { RotateType.Rotate270, FlipType.None,       6 },
+            { RotateType.Rotate90,  FlipType.Vertical,   7 },
+            { RotateType.Rotate90,  FlipType.None,       8 },
+        };
+
+        [Theory]
+        [MemberData("OrientationValues")]
+        public void ImageShouldFlip(RotateType rotateType, FlipType flipType, ushort orientation)
+        {
+            const string path = "TestOutput/AutoOrient";
+            if (!Directory.Exists(path))
+            {
+                Directory.CreateDirectory(path);
+            }
+
+            string file = TestImages.Bmp.F;
+
+            using (FileStream stream = File.OpenRead(file))
+            {
+                string filename = Path.GetFileNameWithoutExtension(file) + "-" + orientation + Path.GetExtension(file);
+
+                Image image = new Image(stream);
+                image.ExifProfile = new ExifProfile();
+                image.ExifProfile.SetValue(ExifTag.Orientation, orientation);
+
+                using (FileStream before = File.OpenWrite($"{path}/before-{filename}"))
+                {
+                    using (FileStream after = File.OpenWrite($"{path}/after-{filename}"))
+                    {
+                        image.RotateFlip(rotateType, flipType)
+                             .Save(before)
+                             .AutoOrient()
+                             .Save(after);
+                    }
+                }
+            }
+        }
+    }
+}

tests/ImageProcessorCore.Tests/TestImages.cs

@@ -38,6 +38,9 @@ namespace ImageProcessorCore.Tests
             private static readonly string folder = "TestImages/Formats/Bmp/";
 
             public static string Car { get { return folder + "Car.bmp"; } }
+
+            public static string F { get { return folder + "F.bmp"; } }
+
             public static string Neg_height { get { return folder + "neg_height.bmp"; } }
         }
 

tests/ImageProcessorCore.Tests/TestImages/Formats/Bmp/F.bmp

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:6da008d2b285b2db946e6d4ebf8569b0ddd4a05ef273b38304cb65afccac87b3
+size 65502