minor code cleanup

src/ImageSharp/Formats/IImageFormat.cs

@@ -6,26 +6,36 @@ using System.Collections.Generic;
 namespace SixLabors.ImageSharp.Formats
 {
     /// <summary>
-    /// Defines the contract for an image format containing metadata with multiple frames.
+    /// Defines the contract for an image format.
     /// </summary>
-    /// <typeparam name="TFormatMetaData">The type of format metadata.</typeparam>
-    /// <typeparam name="TFormatFrameMetaData">The type of format frame metadata.</typeparam>
-    public interface IImageFormat<TFormatMetaData, TFormatFrameMetaData> : IImageFormat<TFormatMetaData>
-        where TFormatMetaData : class
-        where TFormatFrameMetaData : class
+    public interface IImageFormat
     {
         /// <summary>
-        /// Creates a default instance of the format frame metadata.
+        /// Gets the name that describes this image format.
         /// </summary>
-        /// <returns>The <typeparamref name="TFormatFrameMetaData"/>.</returns>
-        TFormatFrameMetaData CreateDefaultFormatFrameMetaData();
+        string Name { get; }
+
+        /// <summary>
+        /// Gets the default mimetype that the image foramt uses
+        /// </summary>
+        string DefaultMimeType { get; }
+
+        /// <summary>
+        /// Gets all the mimetypes that have been used by this image foramt.
+        /// </summary>
+        IEnumerable<string> MimeTypes { get; }
+
+        /// <summary>
+        /// Gets the file extensions this image format commonly uses.
+        /// </summary>
+        IEnumerable<string> FileExtensions { get; }
     }
 
     /// <summary>
     /// Defines the contract for an image format containing metadata.
     /// </summary>
     /// <typeparam name="TFormatMetaData">The type of format metadata.</typeparam>
-    public interface IImageFormat<TFormatMetaData> : IImageFormat
+    public interface IImageFormat<out TFormatMetaData> : IImageFormat
         where TFormatMetaData : class
     {
         /// <summary>
@@ -36,28 +46,18 @@ namespace SixLabors.ImageSharp.Formats
     }
 
     /// <summary>
-    /// Defines the contract for an image format.
+    /// Defines the contract for an image format containing metadata with multiple frames.
     /// </summary>
-    public interface IImageFormat
+    /// <typeparam name="TFormatMetaData">The type of format metadata.</typeparam>
+    /// <typeparam name="TFormatFrameMetaData">The type of format frame metadata.</typeparam>
+    public interface IImageFormat<out TFormatMetaData, out TFormatFrameMetaData> : IImageFormat<TFormatMetaData>
+        where TFormatMetaData : class
+        where TFormatFrameMetaData : class
     {
         /// <summary>
-        /// Gets the name that describes this image format.
-        /// </summary>
-        string Name { get; }
-
-        /// <summary>
-        /// Gets the default mimetype that the image foramt uses
-        /// </summary>
-        string DefaultMimeType { get; }
-
-        /// <summary>
-        /// Gets all the mimetypes that have been used by this image foramt.
-        /// </summary>
-        IEnumerable<string> MimeTypes { get; }
-
-        /// <summary>
-        /// Gets the file extensions this image format commonly uses.
+        /// Creates a default instance of the format frame metadata.
         /// </summary>
-        IEnumerable<string> FileExtensions { get; }
+        /// <returns>The <typeparamref name="TFormatFrameMetaData"/>.</returns>
+        TFormatFrameMetaData CreateDefaultFormatFrameMetaData();
     }
 }

src/ImageSharp/MetaData/ImageFrameMetaData.cs

@@ -12,7 +12,7 @@ namespace SixLabors.ImageSharp.MetaData
     /// </summary>
     public sealed class ImageFrameMetaData
     {
-        private readonly Dictionary<IImageFormat, object> metaData = new Dictionary<IImageFormat, object>();
+        private readonly Dictionary<IImageFormat, object> formatMetaData = new Dictionary<IImageFormat, object>();
 
         /// <summary>
         /// Initializes a new instance of the <see cref="ImageFrameMetaData"/> class.
@@ -32,9 +32,9 @@ namespace SixLabors.ImageSharp.MetaData
         {
             DebugGuard.NotNull(other, nameof(other));
 
-            foreach (KeyValuePair<IImageFormat, object> meta in other.metaData)
+            foreach (KeyValuePair<IImageFormat, object> meta in other.formatMetaData)
             {
-                this.metaData.Add(meta.Key, meta.Value);
+                this.formatMetaData.Add(meta.Key, meta.Value);
             }
         }
 
@@ -54,13 +54,15 @@ namespace SixLabors.ImageSharp.MetaData
         /// <exception cref="ArgumentNullException">key is null.</exception>
         /// <exception cref="ArgumentNullException">value is null.</exception>
         /// <exception cref="ArgumentException">An element with the same key already exists in the <see cref="ImageMetaData"/>.</exception>
-        public void AddOrUpdateFormatMetaData<TFormatMetaData, TFormatFrameMetaData>(IImageFormat<TFormatMetaData, TFormatFrameMetaData> key, TFormatFrameMetaData value)
+        public void AddOrUpdateFormatMetaData<TFormatMetaData, TFormatFrameMetaData>(
+            IImageFormat<TFormatMetaData, TFormatFrameMetaData> key,
+            TFormatFrameMetaData value)
             where TFormatMetaData : class
             where TFormatFrameMetaData : class
         {
             // Don't think this needs to be threadsafe.
             Guard.NotNull(value, nameof(value));
-            this.metaData[key] = value;
+            this.formatMetaData[key] = value;
         }
 
         /// <summary>
@@ -76,7 +78,7 @@ namespace SixLabors.ImageSharp.MetaData
             where TFormatMetaData : class
             where TFormatFrameMetaData : class
         {
-            if (this.metaData.TryGetValue(key, out object meta))
+            if (this.formatMetaData.TryGetValue(key, out object meta))
             {
                 return (TFormatFrameMetaData)meta;
             }

src/ImageSharp/MetaData/ImageMetaData.cs

@@ -26,7 +26,7 @@ namespace SixLabors.ImageSharp.MetaData
         /// </summary>
         public const double DefaultVerticalResolution = 96;
 
-        private readonly Dictionary<IImageFormat, object> metaData = new Dictionary<IImageFormat, object>();
+        private readonly Dictionary<IImageFormat, object> formatMetaData = new Dictionary<IImageFormat, object>();
         private double horizontalResolution;
         private double verticalResolution;
 
@@ -52,9 +52,9 @@ namespace SixLabors.ImageSharp.MetaData
             this.VerticalResolution = other.VerticalResolution;
             this.ResolutionUnits = other.ResolutionUnits;
 
-            foreach (KeyValuePair<IImageFormat, object> meta in other.metaData)
+            foreach (KeyValuePair<IImageFormat, object> meta in other.formatMetaData)
             {
-                this.metaData.Add(meta.Key, meta.Value);
+                this.formatMetaData.Add(meta.Key, meta.Value);
             }
 
             foreach (ImageProperty property in other.Properties)
@@ -145,7 +145,7 @@ namespace SixLabors.ImageSharp.MetaData
         {
             // Don't think this needs to be threadsafe.
             Guard.NotNull(value, nameof(value));
-            this.metaData[key] = value;
+            this.formatMetaData[key] = value;
         }
 
         /// <summary>
@@ -159,7 +159,7 @@ namespace SixLabors.ImageSharp.MetaData
         public TFormatMetaData GetOrAddFormatMetaData<TFormatMetaData>(IImageFormat<TFormatMetaData> key)
              where TFormatMetaData : class
         {
-            if (this.metaData.TryGetValue(key, out object meta))
+            if (this.formatMetaData.TryGetValue(key, out object meta))
             {
                 return (TFormatMetaData)meta;
             }