Merge pull request #448 from SixLabors/js/fix-423

Fix and standardize EXIF dimension transform updates

src/ImageSharp/DefaultInternalImageProcessorContext.cs

@@ -52,8 +52,8 @@ namespace SixLabors.ImageSharp
             if (!this.mutate && this.destination == null)
             {
                 // This will only work if the first processor applied is the cloning one thus
-                // realistically for this optermissation to work the resize must the first processor
+                // realistically for this optimization to work the resize must the first processor
-                // applied any only up processors will take the douple data path.
+                // applied any only up processors will take the double data path.
                 if (processor is ICloningImageProcessor<TPixel> cloningImageProcessor)
                 {
                     this.destination = cloningImageProcessor.CloneAndApply(this.source, rectangle);

src/ImageSharp/Processing/Processors/CloningImageProcessor.cs

@@ -24,7 +24,7 @@ namespace SixLabors.ImageSharp.Processing
 
                 if (clone.Frames.Count != source.Frames.Count)
                 {
-                    throw new ImageProcessingException($"An error occured when processing the image using {this.GetType().Name}. The processor changed the number of frames.");
+                    throw new ImageProcessingException($"An error occurred when processing the image using {this.GetType().Name}. The processor changed the number of frames.");
                 }
 
                 Configuration configuration = source.GetConfiguration();
@@ -64,7 +64,7 @@ namespace SixLabors.ImageSharp.Processing
                 // we now need to move the pixel data/size data from one image base to another
                 if (cloned.Frames.Count != source.Frames.Count)
                 {
-                    throw new ImageProcessingException($"An error occured when processing the image using {this.GetType().Name}. The processor changed the number of frames.");
+                    throw new ImageProcessingException($"An error occurred when processing the image using {this.GetType().Name}. The processor changed the number of frames.");
                 }
 
                 source.SwapPixelsBuffers(cloned);
@@ -72,7 +72,7 @@ namespace SixLabors.ImageSharp.Processing
         }
 
         /// <summary>
-        /// Generates a deep clone of the source image that operatinos should be applied to.
+        /// Generates a deep clone of the source image that operations should be applied to.
         /// </summary>
         /// <param name="source">The source image. Cannot be null.</param>
         /// <param name="sourceRectangle">The source rectangle.</param>

src/ImageSharp/Processing/Processors/Transforms/AffineTransformProcessor.cs

@@ -51,7 +51,7 @@ namespace SixLabors.ImageSharp.Processing.Processors
         public AffineTransformProcessor(Matrix3x2 matrix, IResampler sampler, Size targetDimensions)
             : base(sampler)
         {
-            // Tansforms are inverted else the output is the opposite of the expected.
+            // Transforms are inverted else the output is the opposite of the expected.
             Matrix3x2.Invert(matrix, out matrix);
             this.TransformMatrix = matrix;
             this.targetDimensions = targetDimensions;

src/ImageSharp/Processing/Processors/Transforms/CropProcessor.cs

@@ -60,5 +60,9 @@ namespace SixLabors.ImageSharp.Processing.Processors
                 source.SwapPixelsBuffers(targetPixels);
             }
         }
+
+        /// <inheritdoc/>
+        protected override void AfterImageApply(Image<TPixel> source, Rectangle sourceRectangle)
+            => TransformHelpers.UpdateDimensionalMetData(source);
     }
 }

src/ImageSharp/Processing/Processors/Transforms/InterpolatedTransformProcessorBase.cs

@@ -3,9 +3,7 @@
 
 using System;
 using System.Runtime.CompilerServices;
-using SixLabors.ImageSharp.MetaData.Profiles.Exif;
 using SixLabors.ImageSharp.PixelFormats;
-using SixLabors.Primitives;
 
 namespace SixLabors.ImageSharp.Processing.Processors
 {
@@ -13,7 +11,7 @@ namespace SixLabors.ImageSharp.Processing.Processors
     /// The base class for performing interpolated affine and non-affine transforms.
     /// </summary>
     /// <typeparam name="TPixel">The pixel format.</typeparam>
-    internal abstract class InterpolatedTransformProcessorBase<TPixel> : CloningImageProcessor<TPixel>
+    internal abstract class InterpolatedTransformProcessorBase<TPixel> : TransformProcessorBase<TPixel>
         where TPixel : struct, IPixel<TPixel>
     {
         /// <summary>
@@ -115,25 +113,5 @@ namespace SixLabors.ImageSharp.Processing.Processors
 
             return (MathF.Ceiling(scale * this.Sampler.Radius), scale, ratio);
         }
-
-        /// <inheritdoc/>
-        protected override void AfterImageApply(Image<TPixel> source, Image<TPixel> destination, Rectangle sourceRectangle)
-        {
-            ExifProfile profile = destination.MetaData.ExifProfile;
-            if (profile == null)
-            {
-                return;
-            }
-
-            if (profile.GetValue(ExifTag.PixelXDimension) != null)
-            {
-                profile.SetValue(ExifTag.PixelXDimension, destination.Width);
-            }
-
-            if (profile.GetValue(ExifTag.PixelYDimension) != null)
-            {
-                profile.SetValue(ExifTag.PixelYDimension, destination.Height);
-            }
-        }
     }
 }

src/ImageSharp/Processing/Processors/Transforms/ProjectiveTransformProcessor.cs

@@ -53,7 +53,7 @@ namespace SixLabors.ImageSharp.Processing.Processors
         public ProjectiveTransformProcessor(Matrix4x4 matrix, IResampler sampler, Rectangle rectangle)
             : base(sampler)
         {
-            // Tansforms are inverted else the output is the opposite of the expected.
+            // Transforms are inverted else the output is the opposite of the expected.
             Matrix4x4.Invert(matrix, out matrix);
             this.TransformMatrix = matrix;
             this.targetRectangle = rectangle;

src/ImageSharp/Processing/Processors/Transforms/ResamplingWeightedProcessor.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.Processing.Processors
     /// Adapted from <see href="http://www.realtimerendering.com/resources/GraphicsGems/gemsiii/filter_rcg.c"/>
     /// </summary>
     /// <typeparam name="TPixel">The pixel format.</typeparam>
-    internal abstract class ResamplingWeightedProcessor<TPixel> : CloningImageProcessor<TPixel>
+    internal abstract class ResamplingWeightedProcessor<TPixel> : TransformProcessorBase<TPixel>
         where TPixel : struct, IPixel<TPixel>
     {
         /// <summary>

src/ImageSharp/Processing/Processors/Transforms/TransformProcessorBase.cs

@@ -0,0 +1,20 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.Primitives;
+
+namespace SixLabors.ImageSharp.Processing.Processors
+{
+    /// <summary>
+    /// The base class for all transform processors. Any processor that changes the dimensions of the image should inherit from this.
+    /// </summary>
+    /// <typeparam name="TPixel">The pixel format.</typeparam>
+    internal abstract class TransformProcessorBase<TPixel> : CloningImageProcessor<TPixel>
+         where TPixel : struct, IPixel<TPixel>
+    {
+        /// <inheritdoc/>
+        protected override void AfterImageApply(Image<TPixel> source, Image<TPixel> destination, Rectangle sourceRectangle)
+            => TransformHelpers.UpdateDimensionalMetData(destination);
+    }
+}

src/ImageSharp/Processing/Transforms/TransformHelpers.cs

@@ -3,6 +3,8 @@
 
 using System;
 using System.Numerics;
+using SixLabors.ImageSharp.MetaData.Profiles.Exif;
+using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.Primitives;
 
 namespace SixLabors.ImageSharp
@@ -12,6 +14,50 @@ namespace SixLabors.ImageSharp
     /// </summary>
     internal class TransformHelpers
     {
+        /// <summary>
+        /// Updates the dimensional metadata of a transformed image
+        /// </summary>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
+        /// <param name="image">The image to update</param>
+        public static void UpdateDimensionalMetData<TPixel>(Image<TPixel> image)
+            where TPixel : struct, IPixel<TPixel>
+        {
+            ExifProfile profile = image.MetaData.ExifProfile;
+            if (profile == null)
+            {
+                return;
+            }
+
+            // Removing the previously stored value allows us to set a value with our own data tag if required.
+            if (profile.GetValue(ExifTag.PixelXDimension) != null)
+            {
+                profile.RemoveValue(ExifTag.PixelXDimension);
+
+                if (image.Width <= ushort.MaxValue)
+                {
+                    profile.SetValue(ExifTag.PixelXDimension, (ushort)image.Width);
+                }
+                else
+                {
+                    profile.SetValue(ExifTag.PixelXDimension, (uint)image.Width);
+                }
+            }
+
+            if (profile.GetValue(ExifTag.PixelYDimension) != null)
+            {
+                profile.RemoveValue(ExifTag.PixelYDimension);
+
+                if (image.Height <= ushort.MaxValue)
+                {
+                    profile.SetValue(ExifTag.PixelYDimension, (ushort)image.Height);
+                }
+                else
+                {
+                    profile.SetValue(ExifTag.PixelYDimension, (uint)image.Height);
+                }
+            }
+        }
+
         /// <summary>
         /// Returns the bounding <see cref="Rectangle"/> relative to the source for the given transformation matrix.
         /// </summary>

tests/ImageSharp.Tests/Processing/Transforms/TransformsHelpersTest.cs

@@ -0,0 +1,34 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using SixLabors.ImageSharp.MetaData.Profiles.Exif;
+using SixLabors.ImageSharp.PixelFormats;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Tests.Processing.Transforms
+{
+    public class TransformsHelpersTest
+    {
+        [Fact]
+        public void HelperCanChangeExifDataType()
+        {
+            int xy = 1;
+
+            using (var img = new Image<Alpha8>(xy, xy))
+            {
+                var profile = new ExifProfile();
+                img.MetaData.ExifProfile = profile;
+                profile.SetValue(ExifTag.PixelXDimension, (uint)xy);
+                profile.SetValue(ExifTag.PixelYDimension, (uint)xy);
+
+                Assert.Equal(ExifDataType.Long, profile.GetValue(ExifTag.PixelXDimension).DataType);
+                Assert.Equal(ExifDataType.Long, profile.GetValue(ExifTag.PixelYDimension).DataType);
+
+                TransformHelpers.UpdateDimensionalMetData(img);
+
+                Assert.Equal(ExifDataType.Short, profile.GetValue(ExifTag.PixelXDimension).DataType);
+                Assert.Equal(ExifDataType.Short, profile.GetValue(ExifTag.PixelYDimension).DataType);
+            }
+        }
+    }
+}