Merge pull request #1074 from SixLabors/js/fix-1073

Enumerate once on clone. Fix #1073

Author: JimBobSquarePants

src/ImageSharp/ImageFrameCollection.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Six Labors and contributors.
+// Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
 using System;
@@ -122,7 +122,7 @@ public abstract class ImageFrameCollection : IEnumerable<ImageFrame>
         public IEnumerator<ImageFrame> GetEnumerator() => this.NonGenericGetEnumerator();
 
         /// <inheritdoc/>
-        IEnumerator IEnumerable.GetEnumerator() => this.NonGenericGetEnumerator();
+        IEnumerator IEnumerable.GetEnumerator() => this.GetEnumerator();
 
         /// <summary>
         /// Implements <see cref="GetEnumerator"/>.

src/ImageSharp/Image{TPixel}.cs

@@ -130,7 +130,7 @@ internal Image(Configuration configuration, ImageMetadata metadata, IEnumerable<
         protected override ImageFrameCollection NonGenericFrameCollection => this.Frames;
 
         /// <summary>
-        /// Gets the frames.
+        /// Gets the collection of image frames.
         /// </summary>
         public new ImageFrameCollection<TPixel> Frames { get; }
 
@@ -166,8 +166,12 @@ public Image<TPixel> Clone(Configuration configuration)
         {
             this.EnsureNotDisposed();
 
-            IEnumerable<ImageFrame<TPixel>> clonedFrames =
-                this.Frames.Select<ImageFrame<TPixel>, ImageFrame<TPixel>>(x => x.Clone(configuration));
+            var clonedFrames = new ImageFrame<TPixel>[this.Frames.Count];
+            for (int i = 0; i < clonedFrames.Length; i++)
+            {
+                clonedFrames[i] = this.Frames[i].Clone(configuration);
+            }
+
             return new Image<TPixel>(configuration, this.Metadata.DeepClone(), clonedFrames);
         }
 
@@ -181,8 +185,12 @@ public override Image<TPixel2> CloneAs<TPixel2>(Configuration configuration)
         {
             this.EnsureNotDisposed();
 
-            IEnumerable<ImageFrame<TPixel2>> clonedFrames =
-                this.Frames.Select<ImageFrame<TPixel>, ImageFrame<TPixel2>>(x => x.CloneAs<TPixel2>(configuration));
+            var clonedFrames = new ImageFrame<TPixel2>[this.Frames.Count];
+            for (int i = 0; i < clonedFrames.Length; i++)
+            {
+                clonedFrames[i] = this.Frames[i].CloneAs<TPixel2>(configuration);
+            }
+
             return new Image<TPixel2>(configuration, this.Metadata.DeepClone(), clonedFrames);
         }
 

src/ImageSharp/Processing/Processors/CloningImageProcessor{TPixel}.cs

@@ -173,16 +173,19 @@ private Image<TPixel> CreateTarget()
             Image<TPixel> source = this.Source;
             Size targetSize = this.GetTargetSize();
 
-            // We will always be creating the clone even for mutate because we may need to resize the canvas
-            IEnumerable<ImageFrame<TPixel>> frames = source.Frames.Select<ImageFrame<TPixel>, ImageFrame<TPixel>>(
-                x => new ImageFrame<TPixel>(
+            // We will always be creating the clone even for mutate because we may need to resize the canvas.
+            var targetFrames = new ImageFrame<TPixel>[source.Frames.Count];
+            for (int i = 0; i < targetFrames.Length; i++)
+            {
+                targetFrames[i] = new ImageFrame<TPixel>(
                     this.Configuration,
                     targetSize.Width,
                     targetSize.Height,
-                    x.Metadata.DeepClone()));
+                    source.Frames[i].Metadata.DeepClone());
+            }
 
-            // Use the overload to prevent an extra frame being added
-            return new Image<TPixel>(this.Configuration, source.Metadata.DeepClone(), frames);
+            // Use the overload to prevent an extra frame being added.
+            return new Image<TPixel>(this.Configuration, source.Metadata.DeepClone(), targetFrames);
         }
 
         private void CheckFrameCount(Image<TPixel> a, Image<TPixel> b)