Adding basic EXIF property item manipulation

Former-commit-id: 499d99a0048d840c7434726d0776035d258faa4b

README.md

@@ -5,4 +5,4 @@ Imageprocessor is a lightweight library written in C# that allows you to manipul
 
 It's fast, extensible, easy to use, comes bundled with some great features and is fully open source.
 
-For full documentation please see [http://jimbobsquarepants.github.io/ImageProcessor/](http://jimbobsquarepants.github.io/ImageProcessor/)
+For full documentation please see [http://imageprocessor.org/](http://imageprocessor.org/)

src/ImageProcessor/ImageFactory.cs

@@ -12,6 +12,7 @@ namespace ImageProcessor
 {
     #region Using
     using System;
+    using System.Collections.Concurrent;
     using System.Collections.Generic;
     using System.Diagnostics.CodeAnalysis;
     using System.Drawing;
@@ -19,7 +20,6 @@ namespace ImageProcessor
     using System.IO;
     using System.Linq;
     using System.Threading;
-
     using ImageProcessor.Extensions;
     using ImageProcessor.Imaging;
     using ImageProcessor.Imaging.Filters;
@@ -37,6 +37,11 @@ namespace ImageProcessor
         /// </summary>
         private const int DefaultJpegQuality = 90;
 
+        /// <summary>
+        /// Whether to preserve exif metadata
+        /// </summary>
+        private readonly bool preserveExifData;
+
         /// <summary>
         /// The backup image format.
         /// </summary>
@@ -66,6 +71,20 @@ namespace ImageProcessor
         private bool isDisposed;
         #endregion
 
+        #region Constructors
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ImageFactory"/> class.
+        /// </summary>
+        /// <param name="preserveExifData">
+        /// Whether to preserve exif metadata. Defaults to false.
+        /// </param>
+        public ImageFactory(bool preserveExifData = true)
+        {
+            this.preserveExifData = preserveExifData;
+            this.ExifPropertyItems = new ConcurrentDictionary<int, PropertyItem>();
+        }
+        #endregion
+
         #region Destructors
         /// <summary>
         /// Finalizes an instance of the <see cref="T:ImageProcessor.ImageFactory">ImageFactory</see> class. 
@@ -123,6 +142,11 @@ namespace ImageProcessor
             }
         }
 
+        /// <summary>
+        /// Gets or sets the exif property items.
+        /// </summary>
+        public ConcurrentDictionary<int, PropertyItem> ExifPropertyItems { get; set; }
+
         /// <summary>
         /// Gets or sets the original extension.
         /// </summary>
@@ -157,6 +181,15 @@ namespace ImageProcessor
             this.ImageFormat = this.Image.RawFormat;
             this.backupImageFormat = this.ImageFormat;
             this.isIndexed = ImageUtils.IsIndexed(this.Image);
+
+            if (this.preserveExifData)
+            {
+                foreach (PropertyItem propertyItem in this.Image.PropertyItems)
+                {
+                    this.ExifPropertyItems[propertyItem.Id] = propertyItem;
+                }
+            }
+
             this.ShouldProcess = true;
 
             return this;
@@ -210,6 +243,15 @@ namespace ImageProcessor
                     this.OriginalExtension = Path.GetExtension(this.ImagePath);
                     this.ImageFormat = imageFormat;
                     this.isIndexed = ImageUtils.IsIndexed(this.Image);
+
+                    if (this.preserveExifData)
+                    {
+                        foreach (PropertyItem propertyItem in this.Image.PropertyItems)
+                        {
+                            this.ExifPropertyItems[propertyItem.Id] = propertyItem;
+                        }
+                    }
+
                     this.ShouldProcess = true;
                 }
             }
@@ -419,7 +461,7 @@ namespace ImageProcessor
 
             return this;
         }
-        
+
         /// <summary>
         /// Applies a filter to the current image.
         /// </summary>
@@ -1032,6 +1074,25 @@ namespace ImageProcessor
             {
                 this.Image = processor.Invoke(this);
             }
+
+            // Set the property item information from any Exif metadata.
+            // We do this here so that they can be changed between processor methods.
+            if (this.preserveExifData)
+            {
+                foreach (KeyValuePair<int, PropertyItem> propertItem in this.ExifPropertyItems)
+                {
+                    try
+                    {
+                        this.Image.SetPropertyItem(propertItem.Value);
+                    }
+                    // ReSharper disable once EmptyGeneralCatchClause
+                    catch
+                    {
+                        // Do nothing. The image format does not handle EXIF data.
+                        // TODO: empty catch is fierce code smell.
+                    }
+                }
+            }
         }
         #endregion
     }

src/ImageProcessor/ImageProcessor.csproj

@@ -67,9 +67,11 @@
     <Compile Include="Extensions\StringExtensions.cs" />
     <Compile Include="ImageFactory.cs" />
     <Compile Include="Imaging\AnchorPosition.cs" />
+    <Compile Include="Imaging\ExifPropertyTagType.cs" />
     <Compile Include="Imaging\Convolution.cs" />
     <Compile Include="Imaging\CropLayer.cs" />
     <Compile Include="Imaging\CropMode.cs" />
+    <Compile Include="Imaging\ExifPropertyTag.cs" />
     <Compile Include="Imaging\Filters\MatrixFilterRegexAttribute.cs" />
     <Compile Include="Imaging\Filters\MatrixFilters.cs" />
     <Compile Include="Imaging\GaussianLayer.cs" />

src/ImageProcessor/Imaging/ExifPropertyTagType.cs

@@ -0,0 +1,58 @@
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright file="ExifPropertyTagType.cs" company="James South">
+//   Copyright (c) James South.
+//   Licensed under the Apache License, Version 2.0.
+// </copyright>
+// <summary>
+//   Specifies the data type of the values stored in the value data member of that same PropertyItem object.
+//   <see cref="http://msdn.microsoft.com/en-us/library/system.drawing.imaging.propertyitem.type.aspx" />
+// </summary>
+// --------------------------------------------------------------------------------------------------------------------
+
+namespace ImageProcessor.Imaging
+{
+    /// <summary>
+    /// Specifies the data type of the values stored in the value data member of that same PropertyItem object.
+    /// <see cref="http://msdn.microsoft.com/en-us/library/system.drawing.imaging.propertyitem.type.aspx"/>
+    /// </summary>
+    public enum ExifPropertyTagType : short
+    {
+        /// <summary>Specifies that the value data member is an array of bytes.</summary>
+        Byte = 1,
+
+        /// <summary>
+        /// Specifies that the value data member is a null-terminated ASCII string. If you set the type data member of a
+        /// PropertyItem object to ExifPropertyTagTypeASCII, you should set the length data member to the length of the string
+        /// including the NULL terminator. For example, the string HELLO would have a length of 6.
+        /// </summary>
+        ASCII = 2,
+
+        /// <summary>Specifies that the value data member is an array of unsigned short (16-bit) integers.</summary>
+        Int16 = 3,
+
+        /// <summary>Specifies that the value data member is an array of unsigned long (32-bit) integers.</summary>
+        Int32 = 4,
+
+        /// <summary>
+        /// Specifies that the value data member is an array of pairs of unsigned long integers. Each pair represents a
+        /// fraction; the first integer is the numerator and the second integer is the denominator.
+        /// </summary>
+        Rational = 5,
+
+        /// <summary>
+        /// Specifies that the value data member is an array of bytes that can hold values of any data type.
+        /// </summary>
+        Undefined = 7,
+
+        /// <summary>
+        /// Specifies that the value data member is an array of signed long (32-bit) integers.
+        /// </summary>
+        SLONG = 9,
+
+        /// <summary>
+        /// Specifies that the value data member is an array of pairs of signed long integers. Each pair represents a
+        /// fraction; the first integer is the numerator and the second integer is the denominator.
+        /// </summary>
+        SRational = 10
+    }
+}

src/ImageProcessor/Imaging/ImageUtils.cs

@@ -11,8 +11,12 @@
 namespace ImageProcessor.Imaging
 {
     #region Using
+
+    using System;
     using System.Drawing;
     using System.Drawing.Imaging;
+    using System.Reflection;
+
     #endregion
 
     /// <summary>
@@ -56,5 +60,19 @@ namespace ImageProcessor.Imaging
             // ReSharper disable once BitwiseOperatorOnEnumWithoutFlags
             return (image.PixelFormat & PixelFormat.Indexed) != 0;
         }
+
+        /// <summary>
+        /// Uses reflection to allow the creation of an instance of <see cref="PropertyItem"/>.
+        /// </summary>
+        /// <returns>
+        /// The <see cref="PropertyItem"/>.
+        /// </returns>
+        public static PropertyItem CreatePropertyItem()
+        {
+            Type type = typeof(PropertyItem);
+            ConstructorInfo constructor = type.GetConstructor(BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public, null, new Type[] { }, null);
+
+            return (PropertyItem)constructor.Invoke(null);
+        }
     }
 }

src/ImageProcessor/Settings.StyleCop

@@ -2,7 +2,11 @@
   <GlobalSettings>
     <CollectionProperty Name="RecognizedWords">
       <Value>behaviour</Value>
+      <Value>chrominance</Value>
       <Value>colour</Value>
+      <Value>enum</Value>
+      <Value>exif</Value>
+      <Value>halftoning</Value>
       <Value>lomograph</Value>
       <Value>octree</Value>
       <Value>quantizer</Value>