Introduce non-generic ImageFrameCollection (#941)

* temporarily disable target frameworks

* drop DelegateProcessor

* drop IImageProcessingContext<TPixel>

* drop NamedColors<T>

* drop ColorBuilder<T>

* drop the *Base postfix for clean class hierarchies

* adding basic skeletons

* non-generic ImageFrameCollection API definition

* non-generic ImageFrameCollection tests

* cleanup + docs + more tests

* implement ImageFrameCollection methods

* tests for generic PixelOperations.To<TDest>()

* experimental implementation

* fix .ttinclude

* generate generic From<TSourcePixel>(...)

* fix RgbaVector <--> BT709 Gray pixel conversion

* Gray8 and Gray16 using ConvertFromRgbaScaledVector4() by default

* fixed all conversion tests

* ConstructGif_FromDifferentPixelTypes

* fix xmldoc and other StyelCop findings

* re-enable all target frameworks

* fix NonGenericAddFrame() and NonGenericInsertFrame()

* fix remaining bugs

.gitattributes

@@ -50,7 +50,7 @@
 *.svg               text        eol=lf
 *.targets           text        eol=lf
 *.tt                text        eol=lf
-*.ttinclude         text        eol=lf
+*.ttinclude         text        eol=crlf
 *.txt               text        eol=lf
 *.vb                text        eol=lf
 *.yml               text        eol=lf

src/ImageSharp/Common/Helpers/ImageMaths.cs

@@ -36,6 +36,17 @@ namespace SixLabors.ImageSharp
         public static ushort Get16BitBT709Luminance(ushort r, ushort g, ushort b) =>
             (ushort)((r * .2126F) + (g * .7152F) + (b * .0722F));
 
+        /// <summary>
+        /// Gets the luminance from the rgb components using the formula as specified by ITU-R Recommendation BT.709.
+        /// </summary>
+        /// <param name="r">The red component.</param>
+        /// <param name="g">The green component.</param>
+        /// <param name="b">The blue component.</param>
+        /// <returns>The <see cref="ushort"/>.</returns>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public static ushort Get16BitBT709Luminance(float r, float g, float b) =>
+            (ushort)((r * .2126F) + (g * .7152F) + (b * .0722F));
+
         /// <summary>
         /// Scales a value from a 16 bit <see cref="ushort"/> to it's 8 bit <see cref="byte"/> equivalent.
         /// </summary>
@@ -379,4 +390,4 @@ namespace SixLabors.ImageSharp
             return GetBoundingRectangle(topLeft, bottomRight);
         }
     }
-}
+}

src/ImageSharp/Formats/Jpeg/Components/Decoder/JpegImagePostProcessor.cs

@@ -21,7 +21,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
     /// (4) Packing <see cref="Image{TPixel}"/> pixels from the <see cref="Vector4"/> buffer. <br/>
     /// These operations are executed in <see cref="NumberOfPostProcessorSteps"/> steps.
     /// <see cref="PixelRowsPerStep"/> image rows are converted in one step,
-    /// which means that size of the allocated memory is limited (does not depend on <see cref="ImageFrame{TPixel}.Height"/>).
+    /// which means that size of the allocated memory is limited (does not depend on <see cref="ImageFrame.Height"/>).
     /// </summary>
     internal class JpegImagePostProcessor : IDisposable
     {
@@ -177,4 +177,4 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
             }
         }
     }
-}
+}

src/ImageSharp/Image.cs

@@ -53,6 +53,11 @@ namespace SixLabors.ImageSharp
         /// </summary>
         protected Configuration Configuration { get; }
 
+        /// <summary>
+        /// Gets the <see cref="ImageFrameCollection"/> implementing the public <see cref="Frames"/> property.
+        /// </summary>
+        protected abstract ImageFrameCollection NonGenericFrameCollection { get; }
+
         /// <inheritdoc/>
         public PixelTypeInfo PixelType { get; }
 
@@ -65,6 +70,11 @@ namespace SixLabors.ImageSharp
         /// <inheritdoc/>
         public ImageMetadata Metadata { get; }
 
+        /// <summary>
+        /// Gets the frames of the image as (non-generic) <see cref="ImageFrameCollection"/>.
+        /// </summary>
+        public ImageFrameCollection Frames => this.NonGenericFrameCollection;
+
         /// <summary>
         /// Gets the pixel buffer.
         /// </summary>
@@ -137,4 +147,4 @@ namespace SixLabors.ImageSharp
             }
         }
     }
-}
+}

src/ImageSharp/ImageFrame.LoadPixelData.cs

@@ -9,9 +9,9 @@ using SixLabors.ImageSharp.PixelFormats;
 namespace SixLabors.ImageSharp
 {
     /// <content>
-    /// Adds static methods allowing the creation of new image from raw pixel data.
+    /// Contains methods for loading raw pixel data.
     /// </content>
-    internal static class ImageFrame
+    public partial class ImageFrame
     {
         /// <summary>
         /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given byte array in <typeparamref name="TPixel"/> format.
@@ -22,7 +22,7 @@ namespace SixLabors.ImageSharp
         /// <param name="height">The height of the final image.</param>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <returns>A new <see cref="Image{TPixel}"/>.</returns>
-        public static ImageFrame<TPixel> LoadPixelData<TPixel>(Configuration configuration, ReadOnlySpan<byte> data, int width, int height)
+        internal static ImageFrame<TPixel> LoadPixelData<TPixel>(Configuration configuration, ReadOnlySpan<byte> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
             => LoadPixelData(configuration, MemoryMarshal.Cast<byte, TPixel>(data), width, height);
 
@@ -35,7 +35,7 @@ namespace SixLabors.ImageSharp
         /// <param name="height">The height of the final image.</param>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <returns>A new <see cref="Image{TPixel}"/>.</returns>
-        public static ImageFrame<TPixel> LoadPixelData<TPixel>(Configuration configuration, ReadOnlySpan<TPixel> data, int width, int height)
+        internal static ImageFrame<TPixel> LoadPixelData<TPixel>(Configuration configuration, ReadOnlySpan<TPixel> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
         {
             int count = width * height;
@@ -48,4 +48,4 @@ namespace SixLabors.ImageSharp
             return image;
         }
     }
-}
+}

src/ImageSharp/ImageFrame.cs

@@ -0,0 +1,91 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+
+using SixLabors.ImageSharp.Metadata;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.Memory;
+using SixLabors.Primitives;
+
+namespace SixLabors.ImageSharp
+{
+    /// <summary>
+    /// Represents a pixel-agnostic image frame containing all pixel data and <see cref="ImageFrameMetadata"/>.
+    /// In case of animated formats like gif, it contains the single frame in a animation.
+    /// In all other cases it is the only frame of the image.
+    /// </summary>
+    public abstract partial class ImageFrame : IDisposable
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ImageFrame"/> class.
+        /// </summary>
+        /// <param name="configuration">The <see cref="Configuration"/>.</param>
+        /// <param name="width">The width.</param>
+        /// <param name="height">The height.</param>
+        /// <param name="metadata">The <see cref="ImageFrameMetadata"/>.</param>
+        protected ImageFrame(Configuration configuration, int width, int height, ImageFrameMetadata metadata)
+        {
+            Guard.NotNull(configuration, nameof(configuration));
+            Guard.NotNull(metadata, nameof(metadata));
+
+            this.Configuration = configuration;
+            this.MemoryAllocator = configuration.MemoryAllocator;
+            this.Width = width;
+            this.Height = height;
+            this.Metadata = metadata;
+        }
+
+        /// <summary>
+        /// Gets the <see cref="MemoryAllocator" /> to use for buffer allocations.
+        /// </summary>
+        public MemoryAllocator MemoryAllocator { get; }
+
+        /// <summary>
+        /// Gets the <see cref="Configuration"/> instance associated with this <see cref="ImageFrame{TPixel}"/>.
+        /// </summary>
+        internal Configuration Configuration { get; }
+
+        /// <summary>
+        /// Gets the width.
+        /// </summary>
+        public int Width { get; private set; }
+
+        /// <summary>
+        /// Gets the height.
+        /// </summary>
+        public int Height { get; private set; }
+
+        /// <summary>
+        /// Gets the metadata of the frame.
+        /// </summary>
+        public ImageFrameMetadata Metadata { get; }
+
+        /// <summary>
+        /// Gets the size of the frame.
+        /// </summary>
+        /// <returns>The <see cref="Size"/></returns>
+        public Size Size() => new Size(this.Width, this.Height);
+
+        /// <summary>
+        /// Gets the bounds of the frame.
+        /// </summary>
+        /// <returns>The <see cref="Rectangle"/></returns>
+        public Rectangle Bounds() => new Rectangle(0, 0, this.Width, this.Height);
+
+        /// <inheritdoc />
+        public abstract void Dispose();
+
+        internal abstract void CopyPixelsTo<TDestinationPixel>(Span<TDestinationPixel> destination)
+            where TDestinationPixel : struct, IPixel<TDestinationPixel>;
+
+        /// <summary>
+        /// Updates the size of the image frame.
+        /// </summary>
+        internal void UpdateSize(Size size)
+        {
+            this.Width = size.Width;
+            this.Height = size.Height;
+        }
+    }
+}

src/ImageSharp/ImageFrameCollection.cs

@@ -4,149 +4,69 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
-using SixLabors.ImageSharp.Advanced;
-using SixLabors.ImageSharp.Memory;
-using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp
 {
     /// <summary>
-    /// Encapsulates a collection of <see cref="ImageFrame{T}"/> instances that make up an <see cref="Image{T}"/>.
+    /// Encapsulates a pixel-agnostic collection of <see cref="ImageFrame"/> instances
+    /// that make up an <see cref="Image"/>.
     /// </summary>
-    /// <typeparam name="TPixel">The type of the pixel.</typeparam>
-    public sealed class ImageFrameCollection<TPixel> : IEnumerable<ImageFrame<TPixel>>
-        where TPixel : struct, IPixel<TPixel>
+    public abstract class ImageFrameCollection : IEnumerable<ImageFrame>
     {
-        private readonly IList<ImageFrame<TPixel>> frames = new List<ImageFrame<TPixel>>();
-        private readonly Image<TPixel> parent;
-
-        internal ImageFrameCollection(Image<TPixel> parent, int width, int height, TPixel backgroundColor)
-        {
-            this.parent = parent ?? throw new ArgumentNullException(nameof(parent));
-
-            // Frames are already cloned within the caller
-            this.frames.Add(new ImageFrame<TPixel>(parent.GetConfiguration(), width, height, backgroundColor));
-        }
-
-        internal ImageFrameCollection(Image<TPixel> parent, int width, int height, MemorySource<TPixel> memorySource)
-        {
-            this.parent = parent ?? throw new ArgumentNullException(nameof(parent));
-
-            // Frames are already cloned within the caller
-            this.frames.Add(new ImageFrame<TPixel>(parent.GetConfiguration(), width, height, memorySource));
-        }
-
-        internal ImageFrameCollection(Image<TPixel> parent, IEnumerable<ImageFrame<TPixel>> frames)
-        {
-            Guard.NotNull(parent, nameof(parent));
-            Guard.NotNull(frames, nameof(frames));
-
-            this.parent = parent;
-
-            // Frames are already cloned by the caller
-            foreach (ImageFrame<TPixel> f in frames)
-            {
-                this.ValidateFrame(f);
-                this.frames.Add(f);
-            }
-
-            // Ensure at least 1 frame was added to the frames collection
-            if (this.frames.Count == 0)
-            {
-                throw new ArgumentException("Must not be empty.", nameof(frames));
-            }
-        }
-
         /// <summary>
         /// Gets the number of frames.
         /// </summary>
-        public int Count => this.frames.Count;
+        public abstract int Count { get; }
 
         /// <summary>
         /// Gets the root frame.
         /// </summary>
-        public ImageFrame<TPixel> RootFrame => this.frames.Count > 0 ? this.frames[0] : null;
+        public ImageFrame RootFrame => this.NonGenericRootFrame;
+
+        /// <summary>
+        /// Gets the root frame. (Implements <see cref="RootFrame"/>.)
+        /// </summary>
+        protected abstract ImageFrame NonGenericRootFrame { get; }
 
         /// <summary>
-        /// Gets the <see cref="ImageFrame{TPixel}"/> at the specified index.
+        /// Gets the <see cref="ImageFrame"/> at the specified index.
         /// </summary>
         /// <value>
-        /// The <see cref="ImageFrame{TPixel}"/>.
+        /// The <see cref="ImageFrame"/>.
         /// </value>
         /// <param name="index">The index.</param>
-        /// <returns>The <see cref="ImageFrame{TPixel}"/> at the specified index.</returns>
-        public ImageFrame<TPixel> this[int index] => this.frames[index];
+        /// <returns>The <see cref="ImageFrame"/> at the specified index.</returns>
+        public ImageFrame this[int index] => this.NonGenericGetFrame(index);
 
         /// <summary>
-        /// Determines the index of a specific <paramref name="frame"/> in the <seealso cref="ImageFrameCollection{TPixel}"/>.
+        /// Determines the index of a specific <paramref name="frame"/> in the <seealso cref="ImageFrameCollection"/>.
         /// </summary>
-        /// <param name="frame">The <seealso cref="ImageFrame{TPixel}"/> to locate in the <seealso cref="ImageFrameCollection{TPixel}"/>.</param>
+        /// <param name="frame">The <seealso cref="ImageFrame"/> to locate in the <seealso cref="ImageFrameCollection"/>.</param>
         /// <returns>The index of item if found in the list; otherwise, -1.</returns>
-        public int IndexOf(ImageFrame<TPixel> frame) => this.frames.IndexOf(frame);
+        public abstract int IndexOf(ImageFrame frame);
 
         /// <summary>
-        /// Clones and inserts the <paramref name="source"/> into the <seealso cref="ImageFrameCollection{TPixel}"/> at the specified <paramref name="index"/>.
+        /// Clones and inserts the <paramref name="source"/> into the <seealso cref="ImageFrameCollection"/> at the specified <paramref name="index"/>.
         /// </summary>
         /// <param name="index">The zero-based index to insert the frame at.</param>
-        /// <param name="source">The <seealso cref="ImageFrame{TPixel}"/> to clone and insert into the <seealso cref="ImageFrameCollection{TPixel}"/>.</param>
+        /// <param name="source">The <seealso cref="ImageFrame"/> to clone and insert into the <seealso cref="ImageFrameCollection"/>.</param>
         /// <exception cref="ArgumentException">Frame must have the same dimensions as the image.</exception>
-        /// <returns>The cloned <see cref="ImageFrame{TPixel}"/>.</returns>
-        public ImageFrame<TPixel> InsertFrame(int index, ImageFrame<TPixel> source)
-        {
-            this.ValidateFrame(source);
-            ImageFrame<TPixel> clonedFrame = source.Clone(this.parent.GetConfiguration());
-            this.frames.Insert(index, clonedFrame);
-            return clonedFrame;
-        }
+        /// <returns>The cloned <see cref="ImageFrame"/>.</returns>
+        public ImageFrame InsertFrame(int index, ImageFrame source) => this.NonGenericInsertFrame(index, source);
 
         /// <summary>
         /// Clones the <paramref name="source"/> frame and appends the clone to the end of the collection.
         /// </summary>
         /// <param name="source">The raw pixel data to generate the <seealso cref="ImageFrame{TPixel}"/> from.</param>
         /// <returns>The cloned <see cref="ImageFrame{TPixel}"/>.</returns>
-        public ImageFrame<TPixel> AddFrame(ImageFrame<TPixel> source)
-        {
-            this.ValidateFrame(source);
-            ImageFrame<TPixel> clonedFrame = source.Clone(this.parent.GetConfiguration());
-            this.frames.Add(clonedFrame);
-            return clonedFrame;
-        }
-
-        /// <summary>
-        /// Creates a new frame from the pixel data with the same dimensions as the other frames and inserts the
-        /// new frame at the end of the collection.
-        /// </summary>
-        /// <param name="source">The raw pixel data to generate the <seealso cref="ImageFrame{TPixel}"/> from.</param>
-        /// <returns>The new <see cref="ImageFrame{TPixel}"/>.</returns>
-        public ImageFrame<TPixel> AddFrame(TPixel[] source)
-        {
-            Guard.NotNull(source, nameof(source));
-
-            var frame = ImageFrame.LoadPixelData(
-                this.parent.GetConfiguration(),
-                new ReadOnlySpan<TPixel>(source),
-                this.RootFrame.Width,
-                this.RootFrame.Height);
-            this.frames.Add(frame);
-            return frame;
-        }
+        public ImageFrame AddFrame(ImageFrame source) => this.NonGenericAddFrame(source);
 
         /// <summary>
         /// Removes the frame at the specified index and frees all freeable resources associated with it.
         /// </summary>
         /// <param name="index">The zero-based index of the frame to remove.</param>
         /// <exception cref="InvalidOperationException">Cannot remove last frame.</exception>
-        public void RemoveFrame(int index)
-        {
-            if (index == 0 && this.Count == 1)
-            {
-                throw new InvalidOperationException("Cannot remove last frame.");
-            }
-
-            ImageFrame<TPixel> frame = this.frames[index];
-            this.frames.RemoveAt(index);
-            frame.Dispose();
-        }
+        public abstract void RemoveFrame(int index);
 
         /// <summary>
         /// Determines whether the <seealso cref="ImageFrameCollection{TPixel}"/> contains the <paramref name="frame"/>.
@@ -155,24 +75,14 @@ namespace SixLabors.ImageSharp
         /// <returns>
         ///   <c>true</c> if the <seealso cref="ImageFrameCollection{TPixel}"/> contains the specified frame; otherwise, <c>false</c>.
         /// </returns>
-        public bool Contains(ImageFrame<TPixel> frame) => this.frames.Contains(frame);
+        public abstract bool Contains(ImageFrame frame);
 
         /// <summary>
         /// Moves an <seealso cref="ImageFrame{TPixel}"/> from <paramref name="sourceIndex"/> to <paramref name="destinationIndex"/>.
         /// </summary>
         /// <param name="sourceIndex">The zero-based index of the frame to move.</param>
         /// <param name="destinationIndex">The index to move the frame to.</param>
-        public void MoveFrame(int sourceIndex, int destinationIndex)
-        {
-            if (sourceIndex == destinationIndex)
-            {
-                return;
-            }
-
-            ImageFrame<TPixel> frameAtIndex = this.frames[sourceIndex];
-            this.frames.RemoveAt(sourceIndex);
-            this.frames.Insert(destinationIndex, frameAtIndex);
-        }
+        public abstract void MoveFrame(int sourceIndex, int destinationIndex);
 
         /// <summary>
         /// Removes the frame at the specified index and creates a new image with only the removed frame
@@ -181,19 +91,7 @@ namespace SixLabors.ImageSharp
         /// <param name="index">The zero-based index of the frame to export.</param>
         /// <exception cref="InvalidOperationException">Cannot remove last frame.</exception>
         /// <returns>The new <see cref="Image{TPixel}"/> with the specified frame.</returns>
-        public Image<TPixel> ExportFrame(int index)
-        {
-            ImageFrame<TPixel> frame = this[index];
-
-            if (this.Count == 1 && this.frames.Contains(frame))
-            {
-                throw new InvalidOperationException("Cannot remove last frame.");
-            }
-
-            this.frames.Remove(frame);
-
-            return new Image<TPixel>(this.parent.GetConfiguration(), this.parent.Metadata.DeepClone(), new[] { frame });
-        }
+        public Image ExportFrame(int index) => this.NonGenericExportFrame(index);
 
         /// <summary>
         /// Creates an <see cref="Image{T}"/> with only the frame at the specified index
@@ -201,12 +99,7 @@ namespace SixLabors.ImageSharp
         /// </summary>
         /// <param name="index">The zero-based index of the frame to clone.</param>
         /// <returns>The new <see cref="Image{TPixel}"/> with the specified frame.</returns>
-        public Image<TPixel> CloneFrame(int index)
-        {
-            ImageFrame<TPixel> frame = this[index];
-            ImageFrame<TPixel> clonedFrame = frame.Clone();
-            return new Image<TPixel>(this.parent.GetConfiguration(), this.parent.Metadata.DeepClone(), new[] { clonedFrame });
-        }
+        public Image CloneFrame(int index) => this.NonGenericCloneFrame(index);
 
         /// <summary>
         /// Creates a new <seealso cref="ImageFrame{TPixel}" /> and appends it to the end of the collection.
@@ -214,7 +107,7 @@ namespace SixLabors.ImageSharp
         /// <returns>
         /// The new <see cref="ImageFrame{TPixel}" />.
         /// </returns>
-        public ImageFrame<TPixel> CreateFrame() => this.CreateFrame(default);
+        public ImageFrame CreateFrame() => this.NonGenericCreateFrame();
 
         /// <summary>
         /// Creates a new <seealso cref="ImageFrame{TPixel}" /> and appends it to the end of the collection.
@@ -223,44 +116,67 @@ namespace SixLabors.ImageSharp
         /// <returns>
         /// The new <see cref="ImageFrame{TPixel}" />.
         /// </returns>
-        public ImageFrame<TPixel> CreateFrame(TPixel backgroundColor)
-        {
-            var frame = new ImageFrame<TPixel>(
-                this.parent.GetConfiguration(),
-                this.RootFrame.Width,
-                this.RootFrame.Height,
-                backgroundColor);
-            this.frames.Add(frame);
-            return frame;
-        }
+        public ImageFrame CreateFrame(Color backgroundColor) => this.NonGenericCreateFrame(backgroundColor);
 
-        /// <inheritdoc/>
-        IEnumerator<ImageFrame<TPixel>> IEnumerable<ImageFrame<TPixel>>.GetEnumerator() => this.frames.GetEnumerator();
+        /// <inheritdoc />
+        public IEnumerator<ImageFrame> GetEnumerator() => this.NonGenericGetEnumerator();
 
         /// <inheritdoc/>
-        IEnumerator IEnumerable.GetEnumerator() => ((IEnumerable)this.frames).GetEnumerator();
+        IEnumerator IEnumerable.GetEnumerator() => this.NonGenericGetEnumerator();
 
-        private void ValidateFrame(ImageFrame<TPixel> frame)
-        {
-            Guard.NotNull(frame, nameof(frame));
+        /// <summary>
+        /// Implements <see cref="GetEnumerator"/>.
+        /// </summary>
+        /// <returns>The enumerator.</returns>
+        protected abstract IEnumerator<ImageFrame> NonGenericGetEnumerator();
+
+        /// <summary>
+        /// Implements the getter of the indexer.
+        /// </summary>
+        /// <param name="index">The index.</param>
+        /// <returns>The frame.</returns>
+        protected abstract ImageFrame NonGenericGetFrame(int index);
+
+        /// <summary>
+        /// Implements <see cref="InsertFrame"/>.
+        /// </summary>
+        /// <param name="index">The index.</param>
+        /// <param name="source">The frame.</param>
+        /// <returns>The new frame.</returns>
+        protected abstract ImageFrame NonGenericInsertFrame(int index, ImageFrame source);
+
+        /// <summary>
+        /// Implements <see cref="AddFrame"/>.
+        /// </summary>
+        /// <param name="source">The frame.</param>
+        /// <returns>The new frame.</returns>
+        protected abstract ImageFrame NonGenericAddFrame(ImageFrame source);
+
+        /// <summary>
+        /// Implements <see cref="ExportFrame"/>.
+        /// </summary>
+        /// <param name="index">The index.</param>
+        /// <returns>The new image.</returns>
+        protected abstract Image NonGenericExportFrame(int index);
 
-            if (this.Count != 0)
-            {
-                if (this.RootFrame.Width != frame.Width || this.RootFrame.Height != frame.Height)
-                {
-                    throw new ArgumentException("Frame must have the same dimensions as the image.", nameof(frame));
-                }
-            }
-        }
+        /// <summary>
+        /// Implements <see cref="CloneFrame"/>.
+        /// </summary>
+        /// <param name="index">The index.</param>
+        /// <returns>The new image.</returns>
+        protected abstract Image NonGenericCloneFrame(int index);
 
-        internal void Dispose()
-        {
-            foreach (ImageFrame<TPixel> f in this.frames)
-            {
-                f.Dispose();
-            }
+        /// <summary>
+        /// Implements <see cref="CreateFrame()"/>.
+        /// </summary>
+        /// <returns>The new frame.</returns>
+        protected abstract ImageFrame NonGenericCreateFrame();
 
-            this.frames.Clear();
-        }
+        /// <summary>
+        /// Implements <see cref="CreateFrame()"/>.
+        /// </summary>
+        /// <param name="backgroundColor">The background color.</param>
+        /// <returns>The new frame.</returns>
+        protected abstract ImageFrame NonGenericCreateFrame(Color backgroundColor);
     }
-}
+}

src/ImageSharp/ImageFrameCollection{TPixel}.cs

@@ -0,0 +1,358 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp
+{
+    /// <summary>
+    /// Encapsulates a pixel-specific collection of <see cref="ImageFrame{T}"/> instances
+    /// that make up an <see cref="Image{T}"/>.
+    /// </summary>
+    /// <typeparam name="TPixel">The type of the pixel.</typeparam>
+    public sealed class ImageFrameCollection<TPixel> : ImageFrameCollection, IEnumerable<ImageFrame<TPixel>>
+        where TPixel : struct, IPixel<TPixel>
+    {
+        private readonly IList<ImageFrame<TPixel>> frames = new List<ImageFrame<TPixel>>();
+        private readonly Image<TPixel> parent;
+
+        internal ImageFrameCollection(Image<TPixel> parent, int width, int height, TPixel backgroundColor)
+        {
+            this.parent = parent ?? throw new ArgumentNullException(nameof(parent));
+
+            // Frames are already cloned within the caller
+            this.frames.Add(new ImageFrame<TPixel>(parent.GetConfiguration(), width, height, backgroundColor));
+        }
+
+        internal ImageFrameCollection(Image<TPixel> parent, int width, int height, MemorySource<TPixel> memorySource)
+        {
+            this.parent = parent ?? throw new ArgumentNullException(nameof(parent));
+
+            // Frames are already cloned within the caller
+            this.frames.Add(new ImageFrame<TPixel>(parent.GetConfiguration(), width, height, memorySource));
+        }
+
+        internal ImageFrameCollection(Image<TPixel> parent, IEnumerable<ImageFrame<TPixel>> frames)
+        {
+            Guard.NotNull(parent, nameof(parent));
+            Guard.NotNull(frames, nameof(frames));
+
+            this.parent = parent;
+
+            // Frames are already cloned by the caller
+            foreach (ImageFrame<TPixel> f in frames)
+            {
+                this.ValidateFrame(f);
+                this.frames.Add(f);
+            }
+
+            // Ensure at least 1 frame was added to the frames collection
+            if (this.frames.Count == 0)
+            {
+                throw new ArgumentException("Must not be empty.", nameof(frames));
+            }
+        }
+
+        /// <summary>
+        /// Gets the number of frames.
+        /// </summary>
+        public override int Count => this.frames.Count;
+
+        /// <summary>
+        /// Gets the root frame.
+        /// </summary>
+        public new ImageFrame<TPixel> RootFrame => this.frames.Count > 0 ? this.frames[0] : null;
+
+        /// <inheritdoc />
+        protected override ImageFrame NonGenericRootFrame => this.RootFrame;
+
+        /// <summary>
+        /// Gets the <see cref="ImageFrame{TPixel}"/> at the specified index.
+        /// </summary>
+        /// <value>
+        /// The <see cref="ImageFrame{TPixel}"/>.
+        /// </value>
+        /// <param name="index">The index.</param>
+        /// <returns>The <see cref="ImageFrame{TPixel}"/> at the specified index.</returns>
+        public new ImageFrame<TPixel> this[int index] => this.frames[index];
+
+        /// <inheritdoc />
+        public override int IndexOf(ImageFrame frame)
+        {
+            return frame is ImageFrame<TPixel> specific ? this.IndexOf(specific) : -1;
+        }
+
+        /// <summary>
+        /// Determines the index of a specific <paramref name="frame"/> in the <seealso cref="ImageFrameCollection{TPixel}"/>.
+        /// </summary>
+        /// <param name="frame">The <seealso cref="ImageFrame{TPixel}"/> to locate in the <seealso cref="ImageFrameCollection{TPixel}"/>.</param>
+        /// <returns>The index of item if found in the list; otherwise, -1.</returns>
+        public int IndexOf(ImageFrame<TPixel> frame) => this.frames.IndexOf(frame);
+
+        /// <summary>
+        /// Clones and inserts the <paramref name="source"/> into the <seealso cref="ImageFrameCollection{TPixel}"/> at the specified <paramref name="index"/>.
+        /// </summary>
+        /// <param name="index">The zero-based index to insert the frame at.</param>
+        /// <param name="source">The <seealso cref="ImageFrame{TPixel}"/> to clone and insert into the <seealso cref="ImageFrameCollection{TPixel}"/>.</param>
+        /// <exception cref="ArgumentException">Frame must have the same dimensions as the image.</exception>
+        /// <returns>The cloned <see cref="ImageFrame{TPixel}"/>.</returns>
+        public ImageFrame<TPixel> InsertFrame(int index, ImageFrame<TPixel> source)
+        {
+            this.ValidateFrame(source);
+            ImageFrame<TPixel> clonedFrame = source.Clone(this.parent.GetConfiguration());
+            this.frames.Insert(index, clonedFrame);
+            return clonedFrame;
+        }
+
+        /// <summary>
+        /// Clones the <paramref name="source"/> frame and appends the clone to the end of the collection.
+        /// </summary>
+        /// <param name="source">The raw pixel data to generate the <seealso cref="ImageFrame{TPixel}"/> from.</param>
+        /// <returns>The cloned <see cref="ImageFrame{TPixel}"/>.</returns>
+        public ImageFrame<TPixel> AddFrame(ImageFrame<TPixel> source)
+        {
+            this.ValidateFrame(source);
+            ImageFrame<TPixel> clonedFrame = source.Clone(this.parent.GetConfiguration());
+            this.frames.Add(clonedFrame);
+            return clonedFrame;
+        }
+
+        /// <summary>
+        /// Creates a new frame from the pixel data with the same dimensions as the other frames and inserts the
+        /// new frame at the end of the collection.
+        /// </summary>
+        /// <param name="source">The raw pixel data to generate the <seealso cref="ImageFrame{TPixel}"/> from.</param>
+        /// <returns>The new <see cref="ImageFrame{TPixel}"/>.</returns>
+        public ImageFrame<TPixel> AddFrame(ReadOnlySpan<TPixel> source)
+        {
+            var frame = ImageFrame.LoadPixelData(
+                this.parent.GetConfiguration(),
+                source,
+                this.RootFrame.Width,
+                this.RootFrame.Height);
+            this.frames.Add(frame);
+            return frame;
+        }
+
+        /// <summary>
+        /// Creates a new frame from the pixel data with the same dimensions as the other frames and inserts the
+        /// new frame at the end of the collection.
+        /// </summary>
+        /// <param name="source">The raw pixel data to generate the <seealso cref="ImageFrame{TPixel}"/> from.</param>
+        /// <returns>The new <see cref="ImageFrame{TPixel}"/>.</returns>
+        public ImageFrame<TPixel> AddFrame(TPixel[] source)
+        {
+            Guard.NotNull(source, nameof(source));
+            return this.AddFrame(source.AsSpan());
+        }
+
+        /// <summary>
+        /// Removes the frame at the specified index and frees all freeable resources associated with it.
+        /// </summary>
+        /// <param name="index">The zero-based index of the frame to remove.</param>
+        /// <exception cref="InvalidOperationException">Cannot remove last frame.</exception>
+        public override void RemoveFrame(int index)
+        {
+            if (index == 0 && this.Count == 1)
+            {
+                throw new InvalidOperationException("Cannot remove last frame.");
+            }
+
+            ImageFrame<TPixel> frame = this.frames[index];
+            this.frames.RemoveAt(index);
+            frame.Dispose();
+        }
+
+        /// <inheritdoc />
+        public override bool Contains(ImageFrame frame) =>
+            frame is ImageFrame<TPixel> specific && this.Contains(specific);
+
+        /// <summary>
+        /// Determines whether the <seealso cref="ImageFrameCollection{TPixel}"/> contains the <paramref name="frame"/>.
+        /// </summary>
+        /// <param name="frame">The frame.</param>
+        /// <returns>
+        ///   <c>true</c> if the <seealso cref="ImageFrameCollection{TPixel}"/> contains the specified frame; otherwise, <c>false</c>.
+        /// </returns>
+        public bool Contains(ImageFrame<TPixel> frame) => this.frames.Contains(frame);
+
+        /// <summary>
+        /// Moves an <seealso cref="ImageFrame{TPixel}"/> from <paramref name="sourceIndex"/> to <paramref name="destinationIndex"/>.
+        /// </summary>
+        /// <param name="sourceIndex">The zero-based index of the frame to move.</param>
+        /// <param name="destinationIndex">The index to move the frame to.</param>
+        public override void MoveFrame(int sourceIndex, int destinationIndex)
+        {
+            if (sourceIndex == destinationIndex)
+            {
+                return;
+            }
+
+            ImageFrame<TPixel> frameAtIndex = this.frames[sourceIndex];
+            this.frames.RemoveAt(sourceIndex);
+            this.frames.Insert(destinationIndex, frameAtIndex);
+        }
+
+        /// <summary>
+        /// Removes the frame at the specified index and creates a new image with only the removed frame
+        /// with the same metadata as the original image.
+        /// </summary>
+        /// <param name="index">The zero-based index of the frame to export.</param>
+        /// <exception cref="InvalidOperationException">Cannot remove last frame.</exception>
+        /// <returns>The new <see cref="Image{TPixel}"/> with the specified frame.</returns>
+        public new Image<TPixel> ExportFrame(int index)
+        {
+            ImageFrame<TPixel> frame = this[index];
+
+            if (this.Count == 1 && this.frames.Contains(frame))
+            {
+                throw new InvalidOperationException("Cannot remove last frame.");
+            }
+
+            this.frames.Remove(frame);
+
+            return new Image<TPixel>(this.parent.GetConfiguration(), this.parent.Metadata.DeepClone(), new[] { frame });
+        }
+
+        /// <summary>
+        /// Creates an <see cref="Image{T}"/> with only the frame at the specified index
+        /// with the same metadata as the original image.
+        /// </summary>
+        /// <param name="index">The zero-based index of the frame to clone.</param>
+        /// <returns>The new <see cref="Image{TPixel}"/> with the specified frame.</returns>
+        public new Image<TPixel> CloneFrame(int index)
+        {
+            ImageFrame<TPixel> frame = this[index];
+            ImageFrame<TPixel> clonedFrame = frame.Clone();
+            return new Image<TPixel>(this.parent.GetConfiguration(), this.parent.Metadata.DeepClone(), new[] { clonedFrame });
+        }
+
+        /// <summary>
+        /// Creates a new <seealso cref="ImageFrame{TPixel}" /> and appends it to the end of the collection.
+        /// </summary>
+        /// <returns>
+        /// The new <see cref="ImageFrame{TPixel}" />.
+        /// </returns>
+        public new ImageFrame<TPixel> CreateFrame()
+        {
+            var frame = new ImageFrame<TPixel>(
+                this.parent.GetConfiguration(),
+                this.RootFrame.Width,
+                this.RootFrame.Height);
+            this.frames.Add(frame);
+            return frame;
+        }
+
+        /// <inheritdoc />
+        protected override IEnumerator<ImageFrame> NonGenericGetEnumerator() => this.frames.GetEnumerator();
+
+        /// <inheritdoc />
+        protected override ImageFrame NonGenericGetFrame(int index) => this[index];
+
+        /// <inheritdoc />
+        protected override ImageFrame NonGenericInsertFrame(int index, ImageFrame source)
+        {
+            Guard.NotNull(source, nameof(source));
+
+            if (source is ImageFrame<TPixel> compatibleSource)
+            {
+                return this.InsertFrame(index, compatibleSource);
+            }
+
+            ImageFrame<TPixel> result = this.CopyNonCompatibleFrame(source);
+            this.frames.Insert(index, result);
+            return result;
+        }
+
+        /// <inheritdoc />
+        protected override ImageFrame NonGenericAddFrame(ImageFrame source)
+        {
+            Guard.NotNull(source, nameof(source));
+
+            if (source is ImageFrame<TPixel> compatibleSource)
+            {
+                return this.AddFrame(compatibleSource);
+            }
+
+            ImageFrame<TPixel> result = this.CopyNonCompatibleFrame(source);
+            this.frames.Add(result);
+            return result;
+        }
+
+        /// <inheritdoc />
+        protected override Image NonGenericExportFrame(int index) => this.ExportFrame(index);
+
+        /// <inheritdoc />
+        protected override Image NonGenericCloneFrame(int index) => this.CloneFrame(index);
+
+        /// <inheritdoc />
+        protected override ImageFrame NonGenericCreateFrame(Color backgroundColor) =>
+            this.CreateFrame(backgroundColor.ToPixel<TPixel>());
+
+        /// <inheritdoc />
+        protected override ImageFrame NonGenericCreateFrame() => this.CreateFrame();
+
+        /// <summary>
+        /// Creates a new <seealso cref="ImageFrame{TPixel}" /> and appends it to the end of the collection.
+        /// </summary>
+        /// <param name="backgroundColor">The background color to initialize the pixels with.</param>
+        /// <returns>
+        /// The new <see cref="ImageFrame{TPixel}" />.
+        /// </returns>
+        public ImageFrame<TPixel> CreateFrame(TPixel backgroundColor)
+        {
+            var frame = new ImageFrame<TPixel>(
+                this.parent.GetConfiguration(),
+                this.RootFrame.Width,
+                this.RootFrame.Height,
+                backgroundColor);
+            this.frames.Add(frame);
+            return frame;
+        }
+
+        /// <inheritdoc/>
+        IEnumerator<ImageFrame<TPixel>> IEnumerable<ImageFrame<TPixel>>.GetEnumerator() => this.frames.GetEnumerator();
+
+        /// <inheritdoc/>
+        IEnumerator IEnumerable.GetEnumerator() => ((IEnumerable)this.frames).GetEnumerator();
+
+        private void ValidateFrame(ImageFrame<TPixel> frame)
+        {
+            Guard.NotNull(frame, nameof(frame));
+
+            if (this.Count != 0)
+            {
+                if (this.RootFrame.Width != frame.Width || this.RootFrame.Height != frame.Height)
+                {
+                    throw new ArgumentException("Frame must have the same dimensions as the image.", nameof(frame));
+                }
+            }
+        }
+
+        internal void Dispose()
+        {
+            foreach (ImageFrame<TPixel> f in this.frames)
+            {
+                f.Dispose();
+            }
+
+            this.frames.Clear();
+        }
+
+        private ImageFrame<TPixel> CopyNonCompatibleFrame(ImageFrame source)
+        {
+            ImageFrame<TPixel> result = new ImageFrame<TPixel>(
+                this.parent.GetConfiguration(),
+                source.Size(),
+                source.Metadata.DeepClone());
+            source.CopyPixelsTo(result.PixelBuffer.Span);
+            return result;
+        }
+    }
+}

src/ImageSharp/ImageFrame{TPixel}.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Memory;
@@ -15,10 +16,12 @@ using SixLabors.Primitives;
 namespace SixLabors.ImageSharp
 {
     /// <summary>
-    /// Represents a single frame in a animation.
+    /// Represents a pixel-specific image frame containing all pixel data and <see cref="ImageFrameMetadata"/>.
+    /// In case of animated formats like gif, it contains the single frame in a animation.
+    /// In all other cases it is the only frame of the image.
     /// </summary>
     /// <typeparam name="TPixel">The pixel format.</typeparam>
-    public sealed class ImageFrame<TPixel> : IPixelSource<TPixel>, IDisposable
+    public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>, IDisposable
         where TPixel : struct, IPixel<TPixel>
     {
         private bool isDisposed;
@@ -53,8 +56,12 @@ namespace SixLabors.ImageSharp
         /// <param name="height">The height of the image in pixels.</param>
         /// <param name="metadata">The metadata.</param>
         internal ImageFrame(Configuration configuration, int width, int height, ImageFrameMetadata metadata)
-            : this(configuration, width, height, default(TPixel), metadata)
+            : base(configuration, width, height, metadata)
         {
+            Guard.MustBeGreaterThan(width, 0, nameof(width));
+            Guard.MustBeGreaterThan(height, 0, nameof(height));
+
+            this.PixelBuffer = this.MemoryAllocator.Allocate2D<TPixel>(width, height, AllocationOptions.Clean);
         }
 
         /// <summary>
@@ -78,15 +85,12 @@ namespace SixLabors.ImageSharp
         /// <param name="backgroundColor">The color to clear the image with.</param>
         /// <param name="metadata">The metadata.</param>
         internal ImageFrame(Configuration configuration, int width, int height, TPixel backgroundColor, ImageFrameMetadata metadata)
+            : base(configuration, width, height, metadata)
         {
-            Guard.NotNull(configuration, nameof(configuration));
             Guard.MustBeGreaterThan(width, 0, nameof(width));
             Guard.MustBeGreaterThan(height, 0, nameof(height));
 
-            this.Configuration = configuration;
-            this.MemoryAllocator = configuration.MemoryAllocator;
             this.PixelBuffer = this.MemoryAllocator.Allocate2D<TPixel>(width, height);
-            this.Metadata = metadata ?? new ImageFrameMetadata();
             this.Clear(configuration.GetParallelOptions(), backgroundColor);
         }
 
@@ -111,16 +115,12 @@ namespace SixLabors.ImageSharp
         /// <param name="memorySource">The memory source.</param>
         /// <param name="metadata">The metadata.</param>
         internal ImageFrame(Configuration configuration, int width, int height, MemorySource<TPixel> memorySource, ImageFrameMetadata metadata)
+            : base(configuration, width, height, metadata)
         {
-            Guard.NotNull(configuration, nameof(configuration));
             Guard.MustBeGreaterThan(width, 0, nameof(width));
             Guard.MustBeGreaterThan(height, 0, nameof(height));
-            Guard.NotNull(metadata, nameof(metadata));
 
-            this.Configuration = configuration;
-            this.MemoryAllocator = configuration.MemoryAllocator;
             this.PixelBuffer = new Buffer2D<TPixel>(memorySource, width, height);
-            this.Metadata = metadata;
         }
 
         /// <summary>
@@ -129,27 +129,15 @@ namespace SixLabors.ImageSharp
         /// <param name="configuration">The configuration which allows altering default behaviour or extending the library.</param>
         /// <param name="source">The source.</param>
         internal ImageFrame(Configuration configuration, ImageFrame<TPixel> source)
+            : base(configuration, source.Width, source.Height, source.Metadata.DeepClone())
         {
             Guard.NotNull(configuration, nameof(configuration));
             Guard.NotNull(source, nameof(source));
 
-            this.Configuration = configuration;
-            this.MemoryAllocator = configuration.MemoryAllocator;
             this.PixelBuffer = this.MemoryAllocator.Allocate2D<TPixel>(source.PixelBuffer.Width, source.PixelBuffer.Height);
             source.PixelBuffer.GetSpan().CopyTo(this.PixelBuffer.GetSpan());
-            this.Metadata = source.Metadata.DeepClone();
         }
 
-        /// <summary>
-        /// Gets the <see cref="MemoryAllocator" /> to use for buffer allocations.
-        /// </summary>
-        public MemoryAllocator MemoryAllocator { get; }
-
-        /// <summary>
-        /// Gets the <see cref="Configuration"/> instance associated with this <see cref="ImageFrame{TPixel}"/>.
-        /// </summary>
-        internal Configuration Configuration { get; }
-
         /// <summary>
         /// Gets the image pixels. Not private as Buffer2D requires an array in its constructor.
         /// </summary>
@@ -158,21 +146,6 @@ namespace SixLabors.ImageSharp
         /// <inheritdoc/>
         Buffer2D<TPixel> IPixelSource<TPixel>.PixelBuffer => this.PixelBuffer;
 
-        /// <summary>
-        /// Gets the width.
-        /// </summary>
-        public int Width => this.PixelBuffer.Width;
-
-        /// <summary>
-        /// Gets the height.
-        /// </summary>
-        public int Height => this.PixelBuffer.Height;
-
-        /// <summary>
-        /// Gets the metadata of the frame.
-        /// </summary>
-        public ImageFrameMetadata Metadata { get; }
-
         /// <summary>
         /// Gets or sets the pixel at the specified position.
         /// </summary>
@@ -188,18 +161,6 @@ namespace SixLabors.ImageSharp
             set => this.PixelBuffer[x, y] = value;
         }
 
-        /// <summary>
-        /// Gets the size of the frame.
-        /// </summary>
-        /// <returns>The <see cref="Size"/></returns>
-        public Size Size() => new Size(this.Width, this.Height);
-
-        /// <summary>
-        /// Gets the bounds of the frame.
-        /// </summary>
-        /// <returns>The <see cref="Rectangle"/></returns>
-        public Rectangle Bounds() => new Rectangle(0, 0, this.Width, this.Height);
-
         /// <summary>
         /// Gets a reference to the pixel at the specified position.
         /// </summary>
@@ -232,12 +193,13 @@ namespace SixLabors.ImageSharp
             Guard.NotNull(pixelSource, nameof(pixelSource));
 
             Buffer2D<TPixel>.SwapOrCopyContent(this.PixelBuffer, pixelSource.PixelBuffer);
+            this.UpdateSize(this.PixelBuffer.Size());
         }
 
         /// <summary>
         /// Disposes the object and frees resources for the Garbage Collector.
         /// </summary>
-        internal void Dispose()
+        public override void Dispose()
         {
             if (this.isDisposed)
             {
@@ -251,6 +213,17 @@ namespace SixLabors.ImageSharp
             this.isDisposed = true;
         }
 
+        internal override void CopyPixelsTo<TDestinationPixel>(Span<TDestinationPixel> destination)
+        {
+            if (typeof(TPixel) == typeof(TDestinationPixel))
+            {
+                Span<TPixel> dest1 = MemoryMarshal.Cast<TDestinationPixel, TPixel>(destination);
+                this.PixelBuffer.Span.CopyTo(dest1);
+            }
+
+            PixelOperations<TPixel>.Instance.To(this.Configuration, this.PixelBuffer.Span, destination);
+        }
+
         /// <inheritdoc/>
         public override string ToString() => $"ImageFrame<{typeof(TPixel).Name}>({this.Width}x{this.Height})";
 
@@ -325,8 +298,5 @@ namespace SixLabors.ImageSharp
                 span.Fill(value);
             }
         }
-
-        /// <inheritdoc/>
-        void IDisposable.Dispose() => this.Dispose();
     }
-}
+}

src/ImageSharp/ImageSharp.csproj

@@ -5,6 +5,16 @@
     <AssemblyName>SixLabors.ImageSharp</AssemblyName>
     <AssemblyTitle>SixLabors.ImageSharp</AssemblyTitle>
     <Description>A cross-platform library for the processing of image files; written in C#</Description>
+    <NeutralLanguage>en</NeutralLanguage>
+
+    <VersionPrefix Condition="$(packageversion) != ''">$(packageversion)</VersionPrefix>
+    <VersionPrefix Condition="$(packageversion) == ''">0.0.1</VersionPrefix>
+
+    <TargetFrameworks>netcoreapp2.1;netstandard1.3;netstandard2.0;net472</TargetFrameworks>
+
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+    <AssemblyName>SixLabors.ImageSharp</AssemblyName>
     <PackageId>SixLabors.ImageSharp</PackageId>
     <PackageTags>Image Resize Crop Gif Jpg Jpeg Bitmap Png Core</PackageTags>
     <RootNamespace>SixLabors.ImageSharp</RootNamespace>

src/ImageSharp/Image{TPixel}.cs

@@ -80,7 +80,12 @@ namespace SixLabors.ImageSharp
         /// <param name="width">The width of the image in pixels.</param>
         /// <param name="height">The height of the image in pixels.</param>
         /// <param name="metadata">The images metadata.</param>
-        internal Image(Configuration configuration, MemorySource<TPixel> memorySource, int width, int height, ImageMetadata metadata)
+        internal Image(
+            Configuration configuration,
+            MemorySource<TPixel> memorySource,
+            int width,
+            int height,
+            ImageMetadata metadata)
             : base(configuration, PixelTypeInfo.Create<TPixel>(), metadata, width, height)
         {
             this.Frames = new ImageFrameCollection<TPixel>(this, width, height, memorySource);
@@ -95,7 +100,12 @@ namespace SixLabors.ImageSharp
         /// <param name="height">The height of the image in pixels.</param>
         /// <param name="backgroundColor">The color to initialize the pixels with.</param>
         /// <param name="metadata">The images metadata.</param>
-        internal Image(Configuration configuration, int width, int height, TPixel backgroundColor, ImageMetadata metadata)
+        internal Image(
+            Configuration configuration,
+            int width,
+            int height,
+            TPixel backgroundColor,
+            ImageMetadata metadata)
             : base(configuration, PixelTypeInfo.Create<TPixel>(), metadata, width, height)
         {
             this.Frames = new ImageFrameCollection<TPixel>(this, width, height, backgroundColor);
@@ -114,10 +124,13 @@ namespace SixLabors.ImageSharp
             this.Frames = new ImageFrameCollection<TPixel>(this, frames);
         }
 
+        /// <inheritdoc />
+        protected override ImageFrameCollection NonGenericFrameCollection => this.Frames;
+
         /// <summary>
         /// Gets the frames.
         /// </summary>
-        public ImageFrameCollection<TPixel> Frames { get; }
+        public new ImageFrameCollection<TPixel> Frames { get; }
 
         /// <summary>
         /// Gets the root frame.
@@ -149,7 +162,8 @@ namespace SixLabors.ImageSharp
         /// <returns>Returns a new <see cref="Image{TPixel}"/> with all the same pixel data as the original.</returns>
         public Image<TPixel> Clone(Configuration configuration)
         {
-            IEnumerable<ImageFrame<TPixel>> clonedFrames = this.Frames.Select(x => x.Clone(configuration));
+            IEnumerable<ImageFrame<TPixel>> clonedFrames =
+                this.Frames.Select<ImageFrame<TPixel>, ImageFrame<TPixel>>(x => x.Clone(configuration));
             return new Image<TPixel>(configuration, this.Metadata.DeepClone(), clonedFrames);
         }
 
@@ -161,7 +175,8 @@ namespace SixLabors.ImageSharp
         /// <returns>The <see cref="Image{TPixel2}"/>.</returns>
         public override Image<TPixel2> CloneAs<TPixel2>(Configuration configuration)
         {
-            IEnumerable<ImageFrame<TPixel2>> clonedFrames = this.Frames.Select(x => x.CloneAs<TPixel2>(configuration));
+            IEnumerable<ImageFrame<TPixel2>> clonedFrames =
+                this.Frames.Select<ImageFrame<TPixel>, ImageFrame<TPixel2>>(x => x.CloneAs<TPixel2>(configuration));
             return new Image<TPixel2>(configuration, this.Metadata.DeepClone(), clonedFrames);
         }
 
@@ -214,4 +229,4 @@ namespace SixLabors.ImageSharp
             return rootSize;
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Argb32.PixelOperations.Generated.cs

@@ -11,6 +11,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 
+
 namespace SixLabors.ImageSharp.PixelFormats
 {
     /// <content>
@@ -222,6 +223,15 @@ namespace SixLabors.ImageSharp.PixelFormats
                     dp.FromArgb32(sp);
                 }
             }
+            /// <inheritdoc />
+            internal override void From<TSourcePixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<Argb32> destinationPixels)
+            {
+                PixelOperations<TSourcePixel>.Instance.ToArgb32(configuration, sourcePixels, destinationPixels);
+            }
+
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Argb32.PixelOperations.Generated.tt

@@ -16,4 +16,4 @@ namespace SixLabors.ImageSharp.PixelFormats
             <# GenerateAllDefaultConversionMethods("Argb32"); #>
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Bgr24.PixelOperations.Generated.cs

@@ -11,6 +11,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 
+
 namespace SixLabors.ImageSharp.PixelFormats
 {
     /// <content>
@@ -196,6 +197,15 @@ namespace SixLabors.ImageSharp.PixelFormats
                     dp.FromBgr24(sp);
                 }
             }
+            /// <inheritdoc />
+            internal override void From<TSourcePixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<Bgr24> destinationPixels)
+            {
+                PixelOperations<TSourcePixel>.Instance.ToBgr24(configuration, sourcePixels, destinationPixels);
+            }
+
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Bgr24.PixelOperations.Generated.tt

@@ -16,4 +16,4 @@ namespace SixLabors.ImageSharp.PixelFormats
             <# GenerateAllDefaultConversionMethods("Bgr24"); #>
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Bgra32.PixelOperations.Generated.cs

@@ -11,6 +11,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 
+
 namespace SixLabors.ImageSharp.PixelFormats
 {
     /// <content>
@@ -222,6 +223,15 @@ namespace SixLabors.ImageSharp.PixelFormats
                     dp.FromBgra32(sp);
                 }
             }
+            /// <inheritdoc />
+            internal override void From<TSourcePixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<Bgra32> destinationPixels)
+            {
+                PixelOperations<TSourcePixel>.Instance.ToBgra32(configuration, sourcePixels, destinationPixels);
+            }
+
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Bgra32.PixelOperations.Generated.tt

@@ -16,4 +16,4 @@ namespace SixLabors.ImageSharp.PixelFormats
             <# GenerateAllDefaultConversionMethods("Bgra32"); #>
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Gray16.PixelOperations.Generated.cs

@@ -11,6 +11,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 
+
 namespace SixLabors.ImageSharp.PixelFormats
 {
     /// <content>
@@ -185,6 +186,15 @@ namespace SixLabors.ImageSharp.PixelFormats
                     dp.FromGray16(sp);
                 }
             }
+            /// <inheritdoc />
+            internal override void From<TSourcePixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<Gray16> destinationPixels)
+            {
+                PixelOperations<TSourcePixel>.Instance.ToGray16(configuration, sourcePixels, destinationPixels);
+            }
+
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Gray16.PixelOperations.Generated.tt

@@ -16,4 +16,4 @@ namespace SixLabors.ImageSharp.PixelFormats
             <# GenerateAllDefaultConversionMethods("Gray16"); #>
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Gray8.PixelOperations.Generated.cs

@@ -11,6 +11,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 
+
 namespace SixLabors.ImageSharp.PixelFormats
 {
     /// <content>
@@ -185,6 +186,15 @@ namespace SixLabors.ImageSharp.PixelFormats
                     dp.FromGray8(sp);
                 }
             }
+            /// <inheritdoc />
+            internal override void From<TSourcePixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<Gray8> destinationPixels)
+            {
+                PixelOperations<TSourcePixel>.Instance.ToGray8(configuration, sourcePixels, destinationPixels);
+            }
+
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Gray8.PixelOperations.Generated.tt

@@ -16,4 +16,4 @@ namespace SixLabors.ImageSharp.PixelFormats
             <# GenerateAllDefaultConversionMethods("Gray8"); #>
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Rgb24.PixelOperations.Generated.cs

@@ -11,6 +11,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 
+
 namespace SixLabors.ImageSharp.PixelFormats
 {
     /// <content>
@@ -196,6 +197,15 @@ namespace SixLabors.ImageSharp.PixelFormats
                     dp.FromRgb24(sp);
                 }
             }
+            /// <inheritdoc />
+            internal override void From<TSourcePixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<Rgb24> destinationPixels)
+            {
+                PixelOperations<TSourcePixel>.Instance.ToRgb24(configuration, sourcePixels, destinationPixels);
+            }
+
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Rgb24.PixelOperations.Generated.tt

@@ -16,4 +16,4 @@ namespace SixLabors.ImageSharp.PixelFormats
             <# GenerateAllDefaultConversionMethods("Rgb24"); #>
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Rgb48.PixelOperations.Generated.cs

@@ -11,6 +11,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 
+
 namespace SixLabors.ImageSharp.PixelFormats
 {
     /// <content>
@@ -185,6 +186,15 @@ namespace SixLabors.ImageSharp.PixelFormats
                     dp.FromRgb48(sp);
                 }
             }
+            /// <inheritdoc />
+            internal override void From<TSourcePixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<Rgb48> destinationPixels)
+            {
+                PixelOperations<TSourcePixel>.Instance.ToRgb48(configuration, sourcePixels, destinationPixels);
+            }
+
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Rgb48.PixelOperations.Generated.tt

@@ -16,4 +16,4 @@ namespace SixLabors.ImageSharp.PixelFormats
             <# GenerateAllDefaultConversionMethods("Rgb48"); #>
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Rgba32.PixelOperations.Generated.cs

@@ -11,6 +11,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 
+
 namespace SixLabors.ImageSharp.PixelFormats
 {
     /// <content>
@@ -211,6 +212,15 @@ namespace SixLabors.ImageSharp.PixelFormats
                     dp.FromRgba32(sp);
                 }
             }
+            /// <inheritdoc />
+            internal override void From<TSourcePixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<Rgba32> destinationPixels)
+            {
+                PixelOperations<TSourcePixel>.Instance.ToRgba32(configuration, sourcePixels, destinationPixels);
+            }
+
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Rgba32.PixelOperations.Generated.tt

@@ -16,4 +16,4 @@ namespace SixLabors.ImageSharp.PixelFormats
             <# GenerateAllDefaultConversionMethods("Rgba32"); #>
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Rgba64.PixelOperations.Generated.cs

@@ -11,6 +11,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 
+
 namespace SixLabors.ImageSharp.PixelFormats
 {
     /// <content>
@@ -185,6 +186,15 @@ namespace SixLabors.ImageSharp.PixelFormats
                     dp.FromRgba64(sp);
                 }
             }
+            /// <inheritdoc />
+            internal override void From<TSourcePixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<Rgba64> destinationPixels)
+            {
+                PixelOperations<TSourcePixel>.Instance.ToRgba64(configuration, sourcePixels, destinationPixels);
+            }
+
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/Rgba64.PixelOperations.Generated.tt

@@ -16,4 +16,4 @@ namespace SixLabors.ImageSharp.PixelFormats
             <# GenerateAllDefaultConversionMethods("Rgba64"); #>
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Generated/_Common.ttinclude

@@ -22,6 +22,19 @@ using System.Runtime.InteropServices;
     // Types with Rgba32-combatible to/from Vector4 conversion
     static readonly string[] Rgba32CompatibleTypes = { "Argb32", "Bgra32", "Rgb24", "Bgr24" };
 
+    void GenerateGenericConverterMethods(string pixelType)
+    {
+#>
+            /// <inheritdoc />
+            internal override void From<TSourcePixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<<#=pixelType#>> destinationPixels)
+            {
+                PixelOperations<TSourcePixel>.Instance.To<#=pixelType#>(configuration, sourcePixels, destinationPixels);
+            }
+<#+
+    }
 
     void GenerateDefaultSelfConversionMethods(string pixelType)
     {
@@ -117,7 +130,7 @@ using System.Runtime.InteropServices;
            }
 #>
             /// <inheritdoc />
-            internal override void FromVector4(Configuration configuration, Span<Vector4> sourceVectors, Span<<#=pixelType#>> destPixels, PixelConversionModifiers modifiers)
+            internal override void FromVector4Destructive(Configuration configuration, Span<Vector4> sourceVectors, Span<<#=pixelType#>> destPixels, PixelConversionModifiers modifiers)
             {
                 Vector4Converters.RgbaCompatible.FromVector4(configuration, this, sourceVectors, destPixels, modifiers.Remove(<#=removeTheseModifiers#>));
             }
@@ -156,5 +169,7 @@ using System.Runtime.InteropServices;
         {
             GenerateDefaultConvertToMethod(pixelType, destPixelType);
         }
+
+        GenerateGenericConverterMethods(pixelType);
     }
 #>

src/ImageSharp/PixelFormats/PixelImplementations/Gray16.cs

@@ -54,7 +54,7 @@ namespace SixLabors.ImageSharp.PixelFormats
 
         /// <inheritdoc/>
         [MethodImpl(InliningOptions.ShortMethod)]
-        public void FromScaledVector4(Vector4 vector) => this.FromVector4(vector);
+        public void FromScaledVector4(Vector4 vector) => this.ConvertFromRgbaScaledVector4(vector);
 
         /// <inheritdoc/>
         [MethodImpl(InliningOptions.ShortMethod)]
@@ -62,11 +62,7 @@ namespace SixLabors.ImageSharp.PixelFormats
 
         /// <inheritdoc />
         [MethodImpl(InliningOptions.ShortMethod)]
-        public void FromVector4(Vector4 vector)
-        {
-            vector = Vector4.Clamp(vector, Vector4.Zero, Vector4.One) * Max * Average;
-            this.PackedValue = (ushort)MathF.Round(vector.X + vector.Y + vector.Z);
-        }
+        public void FromVector4(Vector4 vector) => this.ConvertFromRgbaScaledVector4(vector);
 
         /// <inheritdoc />
         [MethodImpl(InliningOptions.ShortMethod)]
@@ -176,9 +172,9 @@ namespace SixLabors.ImageSharp.PixelFormats
         {
             vector = Vector4.Clamp(vector, Vector4.Zero, Vector4.One) * Max;
             this.PackedValue = ImageMaths.Get16BitBT709Luminance(
-                (ushort)MathF.Round(vector.X),
-                (ushort)MathF.Round(vector.Y),
-                (ushort)MathF.Round(vector.Z));
+                vector.X,
+                vector.Y,
+                vector.Z);
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/Gray8.cs

@@ -59,7 +59,7 @@ namespace SixLabors.ImageSharp.PixelFormats
 
         /// <inheritdoc/>
         [MethodImpl(InliningOptions.ShortMethod)]
-        public void FromScaledVector4(Vector4 vector) => this.FromVector4(vector);
+        public void FromScaledVector4(Vector4 vector) => this.ConvertFromRgbaScaledVector4(vector);
 
         /// <inheritdoc/>
         [MethodImpl(InliningOptions.ShortMethod)]
@@ -67,15 +67,7 @@ namespace SixLabors.ImageSharp.PixelFormats
 
         /// <inheritdoc />
         [MethodImpl(InliningOptions.ShortMethod)]
-        public void FromVector4(Vector4 vector)
-        {
-            vector = Vector4.Max(Min, vector);
-            vector = Vector4.Min(Max, vector);
-
-            float roundedSum = Vector4.Dot(vector, Accumulator);
-
-            this.PackedValue = (byte)roundedSum;
-        }
+        public void FromVector4(Vector4 vector) => this.ConvertFromRgbaScaledVector4(vector);
 
         /// <inheritdoc />
         [MethodImpl(InliningOptions.ShortMethod)]
@@ -166,4 +158,4 @@ namespace SixLabors.ImageSharp.PixelFormats
             this.PackedValue = ImageMaths.Get8BitBT709Luminance((byte)vector.X, (byte)vector.Y, (byte)vector.Z);
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelImplementations/RgbaVector.PixelOperations.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Numerics;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 using SixLabors.ImageSharp.PixelFormats.Utils;
@@ -44,6 +45,38 @@ namespace SixLabors.ImageSharp.PixelFormats
                 MemoryMarshal.Cast<RgbaVector, Vector4>(sourcePixels).CopyTo(destVectors);
                 Vector4Converters.ApplyForwardConversionModifiers(destVectors, modifiers);
             }
+
+            internal override void ToGray8(Configuration configuration, ReadOnlySpan<RgbaVector> sourcePixels, Span<Gray8> destPixels)
+            {
+                Guard.DestinationShouldNotBeTooShort(sourcePixels, destPixels, nameof(destPixels));
+
+                ref Vector4 sourceBaseRef = ref Unsafe.As<RgbaVector, Vector4>(ref MemoryMarshal.GetReference(sourcePixels));
+                ref Gray8 destBaseRef = ref MemoryMarshal.GetReference(destPixels);
+
+                for (int i = 0; i < sourcePixels.Length; i++)
+                {
+                    ref Vector4 sp = ref Unsafe.Add(ref sourceBaseRef, i);
+                    ref Gray8 dp = ref Unsafe.Add(ref destBaseRef, i);
+
+                    dp.ConvertFromRgbaScaledVector4(sp);
+                }
+            }
+
+            internal override void ToGray16(Configuration configuration, ReadOnlySpan<RgbaVector> sourcePixels, Span<Gray16> destPixels)
+            {
+                Guard.DestinationShouldNotBeTooShort(sourcePixels, destPixels, nameof(destPixels));
+
+                ref Vector4 sourceBaseRef = ref Unsafe.As<RgbaVector, Vector4>(ref MemoryMarshal.GetReference(sourcePixels));
+                ref Gray16 destBaseRef = ref MemoryMarshal.GetReference(destPixels);
+
+                for (int i = 0; i < sourcePixels.Length; i++)
+                {
+                    ref Vector4 sp = ref Unsafe.Add(ref sourceBaseRef, i);
+                    ref Gray16 dp = ref Unsafe.Add(ref destBaseRef, i);
+
+                    dp.ConvertFromRgbaScaledVector4(sp);
+                }
+            }
         }
     }
-}
+}

src/ImageSharp/PixelFormats/PixelOperations{TPixel}.cs

@@ -7,6 +7,8 @@ using System.Numerics;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
+using SixLabors.ImageSharp.Memory;
+
 namespace SixLabors.ImageSharp.PixelFormats
 {
     /// <summary>
@@ -89,63 +91,56 @@ namespace SixLabors.ImageSharp.PixelFormats
             Span<Vector4> destVectors) =>
             this.ToVector4(configuration, sourcePixels, destVectors, PixelConversionModifiers.None);
 
-        /// <summary>
-        /// Converts 'sourceColors.Length' pixels from 'sourceColors' into 'destinationColors'.
-        /// </summary>
-        /// <typeparam name="TDestinationPixel">The destination pixel type.</typeparam>
-        /// <param name="configuration">A <see cref="Configuration"/> to configure internal operations</param>
-        /// <param name="sourceColors">The <see cref="Span{T}"/> to the source colors.</param>
-        /// <param name="destinationColors">The <see cref="Span{T}"/> to the destination colors.</param>
-        internal virtual void To<TDestinationPixel>(
+        internal virtual void From<TSourcePixel>(
             Configuration configuration,
-            ReadOnlySpan<TPixel> sourceColors,
-            Span<TDestinationPixel> destinationColors)
-            where TDestinationPixel : struct, IPixel<TDestinationPixel>
+            ReadOnlySpan<TSourcePixel> sourcePixels,
+            Span<TPixel> destinationPixels)
+            where TSourcePixel : struct, IPixel<TSourcePixel>
         {
-            Guard.NotNull(configuration, nameof(configuration));
-            Guard.DestinationShouldNotBeTooShort(sourceColors, destinationColors, nameof(destinationColors));
-
-            int count = sourceColors.Length;
-            ref TPixel sourceRef = ref MemoryMarshal.GetReference(sourceColors);
-
-            // Gray8 and Gray16 are special implementations of IPixel in that they do not conform to the
-            // standard RGBA colorspace format and must be converted from RGBA using the special ITU BT709 algorithm.
-            // One of the requirements of FromScaledVector4/ToScaledVector4 is that it unaware of this and
-            // packs/unpacks the pixel without and conversion so we employ custom methods do do this.
-            if (typeof(TDestinationPixel) == typeof(Gray16))
+            const int SliceLength = 1024;
+            int numberOfSlices = sourcePixels.Length / SliceLength;
+            using (IMemoryOwner<Vector4> tempVectors = configuration.MemoryAllocator.Allocate<Vector4>(SliceLength))
             {
-                ref Gray16 gray16Ref = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<TDestinationPixel, Gray16>(destinationColors));
-                for (int i = 0; i < count; i++)
+                Span<Vector4> vectorSpan = tempVectors.GetSpan();
+                for (int i = 0; i < numberOfSlices; i++)
                 {
-                    ref TPixel sp = ref Unsafe.Add(ref sourceRef, i);
-                    ref Gray16 dp = ref Unsafe.Add(ref gray16Ref, i);
-                    dp.ConvertFromRgbaScaledVector4(sp.ToScaledVector4());
+                    int start = i * SliceLength;
+                    ReadOnlySpan<TSourcePixel> s = sourcePixels.Slice(start, SliceLength);
+                    Span<TPixel> d = destinationPixels.Slice(start, SliceLength);
+                    PixelOperations<TSourcePixel>.Instance.ToVector4(configuration, s, vectorSpan);
+                    this.FromVector4Destructive(configuration, vectorSpan, d);
                 }
 
-                return;
-            }
-
-            if (typeof(TDestinationPixel) == typeof(Gray8))
-            {
-                ref Gray8 gray8Ref = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<TDestinationPixel, Gray8>(destinationColors));
-                for (int i = 0; i < count; i++)
+                int endOfCompleteSlices = numberOfSlices * SliceLength;
+                int remainder = sourcePixels.Length - endOfCompleteSlices;
+                if (remainder > 0)
                 {
-                    ref TPixel sp = ref Unsafe.Add(ref sourceRef, i);
-                    ref Gray8 dp = ref Unsafe.Add(ref gray8Ref, i);
-                    dp.ConvertFromRgbaScaledVector4(sp.ToScaledVector4());
+                    ReadOnlySpan<TSourcePixel> s = sourcePixels.Slice(endOfCompleteSlices);
+                    Span<TPixel> d = destinationPixels.Slice(endOfCompleteSlices);
+                    vectorSpan = vectorSpan.Slice(0, remainder);
+                    PixelOperations<TSourcePixel>.Instance.ToVector4(configuration, s, vectorSpan);
+                    this.FromVector4Destructive(configuration, vectorSpan, d);
                 }
-
-                return;
             }
+        }
 
-            // Normal conversion
-            ref TDestinationPixel destRef = ref MemoryMarshal.GetReference(destinationColors);
-            for (int i = 0; i < count; i++)
-            {
-                ref TPixel sp = ref Unsafe.Add(ref sourceRef, i);
-                ref TDestinationPixel dp = ref Unsafe.Add(ref destRef, i);
-                dp.FromScaledVector4(sp.ToScaledVector4());
-            }
+        /// <summary>
+        /// Converts 'sourcePixels.Length' pixels from 'sourcePixels' into 'destinationPixels'.
+        /// </summary>
+        /// <typeparam name="TDestinationPixel">The destination pixel type.</typeparam>
+        /// <param name="configuration">A <see cref="Configuration"/> to configure internal operations.</param>
+        /// <param name="sourcePixels">The <see cref="Span{T}"/> to the source pixels.</param>
+        /// <param name="destinationPixels">The <see cref="Span{T}"/> to the destination pixels.</param>
+        internal virtual void To<TDestinationPixel>(
+            Configuration configuration,
+            ReadOnlySpan<TPixel> sourcePixels,
+            Span<TDestinationPixel> destinationPixels)
+            where TDestinationPixel : struct, IPixel<TDestinationPixel>
+        {
+            Guard.NotNull(configuration, nameof(configuration));
+            Guard.DestinationShouldNotBeTooShort(sourcePixels, destinationPixels, nameof(destinationPixels));
+
+            PixelOperations<TDestinationPixel>.Instance.From(configuration, sourcePixels, destinationPixels);
         }
     }
-}
+}

src/ImageSharp/Processing/Processors/Transforms/AffineTransformProcessor{TPixel}.cs

@@ -35,7 +35,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         protected override Image<TPixel> CreateDestination(Image<TPixel> source, Rectangle sourceRectangle)
         {
             // 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(
+            IEnumerable<ImageFrame<TPixel>> frames = source.Frames.Select<ImageFrame<TPixel>, ImageFrame<TPixel>>(
                 x => new ImageFrame<TPixel>(source.GetConfiguration(), this.TargetDimensions, x.Metadata.DeepClone()));
 
             // Use the overload to prevent an extra frame being added

src/ImageSharp/Processing/Processors/Transforms/CropProcessor{TPixel}.cs

@@ -36,7 +36,12 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         protected override Image<TPixel> CreateDestination(Image<TPixel> source, Rectangle sourceRectangle)
         {
             // 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(x => new ImageFrame<TPixel>(source.GetConfiguration(), this.CropRectangle.Width, this.CropRectangle.Height, x.Metadata.DeepClone()));
+            IEnumerable<ImageFrame<TPixel>> frames = source.Frames.Select<ImageFrame<TPixel>, ImageFrame<TPixel>>(
+                x => new ImageFrame<TPixel>(
+                    source.GetConfiguration(),
+                    this.CropRectangle.Width,
+                    this.CropRectangle.Height,
+                    x.Metadata.DeepClone()));
 
             // Use the overload to prevent an extra frame being added
             return new Image<TPixel>(source.GetConfiguration(), source.Metadata.DeepClone(), frames);

src/ImageSharp/Processing/Processors/Transforms/ProjectiveTransformProcessor{TPixel}.cs

@@ -33,7 +33,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         protected override Image<TPixel> CreateDestination(Image<TPixel> source, Rectangle sourceRectangle)
         {
             // 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(
+            IEnumerable<ImageFrame<TPixel>> frames = source.Frames.Select<ImageFrame<TPixel>, ImageFrame<TPixel>>(
                 x => new ImageFrame<TPixel>(
                     source.GetConfiguration(),
                     this.TargetDimensions.Width,
@@ -140,4 +140,4 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             }
         }
     }
-}
+}

src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeProcessor{TPixel}.cs

@@ -68,7 +68,12 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         protected override Image<TPixel> CreateDestination(Image<TPixel> source, Rectangle sourceRectangle)
         {
             // 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(x => new ImageFrame<TPixel>(source.GetConfiguration(), this.Width, this.Height, x.Metadata.DeepClone()));
+            IEnumerable<ImageFrame<TPixel>> frames = source.Frames.Select<ImageFrame<TPixel>, ImageFrame<TPixel>>(
+                x => new ImageFrame<TPixel>(
+                    source.GetConfiguration(),
+                    this.Width,
+                    this.Height,
+                    x.Metadata.DeepClone()));
 
             // Use the overload to prevent an extra frame being added
             return new Image<TPixel>(source.GetConfiguration(), source.Metadata.DeepClone(), frames);

tests/ImageSharp.Tests/Image/ImageFrameCollectionTests.Generic.cs

@@ -0,0 +1,346 @@
+// // Copyright (c) Six Labors and contributors.
+// // Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Linq;
+
+using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.PixelFormats;
+
+using Xunit;
+
+namespace SixLabors.ImageSharp.Tests
+{
+    public abstract partial class ImageFrameCollectionTests
+    {
+        [GroupOutput("ImageFramesCollectionTests")]
+        public class Generic : ImageFrameCollectionTests
+        {
+            [Fact]
+            public void Constructor_ShouldCreateOneFrame()
+            {
+                Assert.Equal(1, this.Collection.Count);
+            }
+
+            [Fact]
+            public void AddNewFrame_FramesMustHaveSameSize()
+            {
+                ArgumentException ex = Assert.Throws<ArgumentException>(
+                    () =>
+                    {
+                        this.Collection.AddFrame(new ImageFrame<Rgba32>(Configuration.Default, 1, 1));
+                    });
+
+                Assert.StartsWith("Frame must have the same dimensions as the image.", ex.Message);
+            }
+
+            [Fact]
+            public void AddNewFrame_Frame_FramesNotBeNull()
+            {
+                ArgumentNullException ex = Assert.Throws<ArgumentNullException>(
+                    () =>
+                    {
+                        this.Collection.AddFrame((ImageFrame<Rgba32>)null);
+                    });
+
+                Assert.StartsWith("Value cannot be null.", ex.Message);
+            }
+
+            [Fact]
+            public void AddNewFrame_PixelBuffer_DataMustNotBeNull()
+            {
+                Rgba32[] data = null;
+
+                ArgumentNullException ex = Assert.Throws<ArgumentNullException>(
+                    () =>
+                    {
+                        this.Collection.AddFrame(data);
+                    });
+
+                Assert.StartsWith("Value cannot be null.", ex.Message);
+            }
+
+            [Fact]
+            public void AddNewFrame_PixelBuffer_BufferIncorrectSize()
+            {
+                ArgumentOutOfRangeException ex = Assert.Throws<ArgumentOutOfRangeException>(
+                    () =>
+                    {
+                        this.Collection.AddFrame(new Rgba32[0]);
+                    });
+
+                Assert.StartsWith("Value 0 must be greater than or equal to 100.", ex.Message);
+            }
+
+            [Fact]
+            public void InsertNewFrame_FramesMustHaveSameSize()
+            {
+                ArgumentException ex = Assert.Throws<ArgumentException>(
+                    () =>
+                    {
+                        this.Collection.InsertFrame(1, new ImageFrame<Rgba32>(Configuration.Default, 1, 1));
+                    });
+
+                Assert.StartsWith("Frame must have the same dimensions as the image.", ex.Message);
+            }
+
+            [Fact]
+            public void InsertNewFrame_FramesNotBeNull()
+            {
+                ArgumentNullException ex = Assert.Throws<ArgumentNullException>(
+                    () =>
+                    {
+                        this.Collection.InsertFrame(1, null);
+                    });
+
+                Assert.StartsWith("Value cannot be null.", ex.Message);
+            }
+
+            [Fact]
+            public void Constructor_FramesMustHaveSameSize()
+            {
+                ArgumentException ex = Assert.Throws<ArgumentException>(
+                    () =>
+                    {
+                        var collection = new ImageFrameCollection<Rgba32>(
+                            this.Image,
+                            new[]
+                            {
+                                new ImageFrame<Rgba32>(Configuration.Default, 10, 10),
+                                new ImageFrame<Rgba32>(Configuration.Default, 1, 1)
+                            });
+                    });
+
+                Assert.StartsWith("Frame must have the same dimensions as the image.", ex.Message);
+            }
+
+            [Fact]
+            public void RemoveAtFrame_ThrowIfRemovingLastFrame()
+            {
+                var collection = new ImageFrameCollection<Rgba32>(
+                    this.Image,
+                    new[] { new ImageFrame<Rgba32>(Configuration.Default, 10, 10) });
+
+                InvalidOperationException ex = Assert.Throws<InvalidOperationException>(
+                    () =>
+                    {
+                        collection.RemoveFrame(0);
+                    });
+                Assert.Equal("Cannot remove last frame.", ex.Message);
+            }
+
+            [Fact]
+            public void RemoveAtFrame_CanRemoveFrameZeroIfMultipleFramesExist()
+            {
+                var collection = new ImageFrameCollection<Rgba32>(
+                    this.Image,
+                    new[]
+                    {
+                        new ImageFrame<Rgba32>(Configuration.Default, 10, 10),
+                        new ImageFrame<Rgba32>(Configuration.Default, 10, 10)
+                    });
+
+                collection.RemoveFrame(0);
+                Assert.Equal(1, collection.Count);
+            }
+
+            [Fact]
+            public void RootFrameIsFrameAtIndexZero()
+            {
+                var collection = new ImageFrameCollection<Rgba32>(
+                    this.Image,
+                    new[]
+                    {
+                        new ImageFrame<Rgba32>(Configuration.Default, 10, 10),
+                        new ImageFrame<Rgba32>(Configuration.Default, 10, 10)
+                    });
+
+                Assert.Equal(collection.RootFrame, collection[0]);
+            }
+
+            [Fact]
+            public void ConstructorPopulatesFrames()
+            {
+                var collection = new ImageFrameCollection<Rgba32>(
+                    this.Image,
+                    new[]
+                    {
+                        new ImageFrame<Rgba32>(Configuration.Default, 10, 10),
+                        new ImageFrame<Rgba32>(Configuration.Default, 10, 10)
+                    });
+
+                Assert.Equal(2, collection.Count);
+            }
+
+            [Fact]
+            public void DisposeClearsCollection()
+            {
+                var collection = new ImageFrameCollection<Rgba32>(
+                    this.Image,
+                    new[]
+                    {
+                        new ImageFrame<Rgba32>(Configuration.Default, 10, 10),
+                        new ImageFrame<Rgba32>(Configuration.Default, 10, 10)
+                    });
+
+                collection.Dispose();
+
+                Assert.Equal(0, collection.Count);
+            }
+
+            [Fact]
+            public void Dispose_DisposesAllInnerFrames()
+            {
+                var collection = new ImageFrameCollection<Rgba32>(
+                    this.Image,
+                    new[]
+                    {
+                        new ImageFrame<Rgba32>(Configuration.Default, 10, 10),
+                        new ImageFrame<Rgba32>(Configuration.Default, 10, 10)
+                    });
+
+                IPixelSource<Rgba32>[] framesSnapShot = collection.OfType<IPixelSource<Rgba32>>().ToArray();
+                collection.Dispose();
+
+                Assert.All(
+                    framesSnapShot,
+                    f =>
+                    {
+                        // the pixel source of the frame is null after its been disposed.
+                        Assert.Null(f.PixelBuffer);
+                    });
+            }
+
+            [Theory]
+            [WithTestPatternImages(10, 10, PixelTypes.Rgba32)]
+            public void CloneFrame<TPixel>(TestImageProvider<TPixel> provider)
+                where TPixel : struct, IPixel<TPixel>
+            {
+                using (Image<TPixel> img = provider.GetImage())
+                {
+                    img.Frames.AddFrame(new ImageFrame<TPixel>(Configuration.Default, 10, 10)); // add a frame anyway
+                    using (Image<TPixel> cloned = img.Frames.CloneFrame(0))
+                    {
+                        Assert.Equal(2, img.Frames.Count);
+                        cloned.ComparePixelBufferTo(img.GetPixelSpan());
+                    }
+                }
+            }
+
+            [Theory]
+            [WithTestPatternImages(10, 10, PixelTypes.Rgba32)]
+            public void ExtractFrame<TPixel>(TestImageProvider<TPixel> provider)
+                where TPixel : struct, IPixel<TPixel>
+            {
+                using (Image<TPixel> img = provider.GetImage())
+                {
+                    var sourcePixelData = img.GetPixelSpan().ToArray();
+
+                    img.Frames.AddFrame(new ImageFrame<TPixel>(Configuration.Default, 10, 10));
+                    using (Image<TPixel> cloned = img.Frames.ExportFrame(0))
+                    {
+                        Assert.Equal(1, img.Frames.Count);
+                        cloned.ComparePixelBufferTo(sourcePixelData);
+                    }
+                }
+            }
+
+            [Fact]
+            public void CreateFrame_Default()
+            {
+                this.Image.Frames.CreateFrame();
+
+                Assert.Equal(2, this.Image.Frames.Count);
+                this.Image.Frames[1].ComparePixelBufferTo(default(Rgba32));
+            }
+
+            [Fact]
+            public void CreateFrame_CustomFillColor()
+            {
+                this.Image.Frames.CreateFrame(Rgba32.HotPink);
+
+                Assert.Equal(2, this.Image.Frames.Count);
+                this.Image.Frames[1].ComparePixelBufferTo(Rgba32.HotPink);
+            }
+
+            [Fact]
+            public void AddFrameFromPixelData()
+            {
+                var pixelData = this.Image.Frames.RootFrame.GetPixelSpan().ToArray();
+                this.Image.Frames.AddFrame(pixelData);
+                Assert.Equal(2, this.Image.Frames.Count);
+            }
+
+            [Fact]
+            public void AddFrame_clones_sourceFrame()
+            {
+                var pixelData = this.Image.Frames.RootFrame.GetPixelSpan().ToArray();
+                var otherFRame = new ImageFrame<Rgba32>(Configuration.Default, 10, 10);
+                var addedFrame = this.Image.Frames.AddFrame(otherFRame);
+                addedFrame.ComparePixelBufferTo(otherFRame.GetPixelSpan());
+                Assert.NotEqual(otherFRame, addedFrame);
+            }
+
+            [Fact]
+            public void InsertFrame_clones_sourceFrame()
+            {
+                var pixelData = this.Image.Frames.RootFrame.GetPixelSpan().ToArray();
+                var otherFRame = new ImageFrame<Rgba32>(Configuration.Default, 10, 10);
+                var addedFrame = this.Image.Frames.InsertFrame(0, otherFRame);
+                addedFrame.ComparePixelBufferTo(otherFRame.GetPixelSpan());
+                Assert.NotEqual(otherFRame, addedFrame);
+            }
+
+            [Fact]
+            public void MoveFrame_LeavesFrmaeInCorrectLocation()
+            {
+                for (var i = 0; i < 9; i++)
+                {
+                    this.Image.Frames.CreateFrame();
+                }
+
+                var frame = this.Image.Frames[4];
+                this.Image.Frames.MoveFrame(4, 7);
+                var newIndex = this.Image.Frames.IndexOf(frame);
+                Assert.Equal(7, newIndex);
+            }
+
+            [Fact]
+            public void IndexOf_ReturnsCorrectIndex()
+            {
+                for (var i = 0; i < 9; i++)
+                {
+                    this.Image.Frames.CreateFrame();
+                }
+
+                var frame = this.Image.Frames[4];
+                var index = this.Image.Frames.IndexOf(frame);
+                Assert.Equal(4, index);
+            }
+
+            [Fact]
+            public void Contains_TrueIfMember()
+            {
+                for (var i = 0; i < 9; i++)
+                {
+                    this.Image.Frames.CreateFrame();
+                }
+
+                var frame = this.Image.Frames[4];
+                Assert.True(this.Image.Frames.Contains(frame));
+            }
+
+            [Fact]
+            public void Contains_FalseIfNonMember()
+            {
+                for (var i = 0; i < 9; i++)
+                {
+                    this.Image.Frames.CreateFrame();
+                }
+
+                var frame = new ImageFrame<Rgba32>(Configuration.Default, 10, 10);
+                Assert.False(this.Image.Frames.Contains(frame));
+            }
+        }
+    }
+}

tests/ImageSharp.Tests/Image/ImageFrameCollectionTests.NonGeneric.cs

@@ -0,0 +1,325 @@
+// // Copyright (c) Six Labors and contributors.
+// // Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Drawing.Imaging;
+using System.Linq;
+
+using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.Formats.Gif;
+using SixLabors.ImageSharp.PixelFormats;
+
+using Xunit;
+
+namespace SixLabors.ImageSharp.Tests
+{
+    public abstract partial class ImageFrameCollectionTests
+    {
+        [GroupOutput("ImageFramesCollectionTests")]
+        public class NonGeneric : ImageFrameCollectionTests
+        {
+            private new Image Image => base.Image;
+
+            private new ImageFrameCollection Collection => base.Collection;
+
+            [Fact]
+            public void AddFrame_OfDifferentPixelType()
+            {
+                using (Image<Bgra32> sourceImage = new Image<Bgra32>(
+                    this.Image.GetConfiguration(),
+                    this.Image.Width,
+                    this.Image.Height,
+                    (Bgra32)Color.Blue))
+                {
+                    this.Collection.AddFrame(sourceImage.Frames.RootFrame);
+                }
+
+                Rgba32[] expectedAllBlue =
+                    Enumerable.Repeat(Rgba32.Blue, this.Image.Width * this.Image.Height).ToArray();
+
+                Assert.Equal(2, this.Collection.Count);
+                ImageFrame<Rgba32> actualFrame = (ImageFrame<Rgba32>)this.Collection[1];
+
+                actualFrame.ComparePixelBufferTo(expectedAllBlue);
+            }
+
+            [Fact]
+            public void InsertFrame_OfDifferentPixelType()
+            {
+                using (Image<Bgra32> sourceImage = new Image<Bgra32>(
+                    this.Image.GetConfiguration(),
+                    this.Image.Width,
+                    this.Image.Height,
+                    (Bgra32)Color.Blue))
+                {
+                    this.Collection.InsertFrame(0, sourceImage.Frames.RootFrame);
+                }
+
+                Rgba32[] expectedAllBlue =
+                    Enumerable.Repeat(Rgba32.Blue, this.Image.Width * this.Image.Height).ToArray();
+
+                Assert.Equal(2, this.Collection.Count);
+                ImageFrame<Rgba32> actualFrame = (ImageFrame<Rgba32>)this.Collection[0];
+
+                actualFrame.ComparePixelBufferTo(expectedAllBlue);
+
+            }
+
+            [Fact]
+            public void Constructor_ShouldCreateOneFrame()
+            {
+                Assert.Equal(1, this.Collection.Count);
+            }
+
+            [Fact]
+            public void AddNewFrame_FramesMustHaveSameSize()
+            {
+                ArgumentException ex = Assert.Throws<ArgumentException>(
+                    () =>
+                    {
+                        this.Collection.AddFrame(new ImageFrame<Rgba32>(Configuration.Default, 1, 1));
+                    });
+
+                Assert.StartsWith("Frame must have the same dimensions as the image.", ex.Message);
+            }
+
+            [Fact]
+            public void AddNewFrame_Frame_FramesNotBeNull()
+            {
+                ArgumentNullException ex = Assert.Throws<ArgumentNullException>(
+                    () =>
+                    {
+                        this.Collection.AddFrame((ImageFrame<Rgba32>)null);
+                    });
+
+                Assert.StartsWith("Value cannot be null.", ex.Message);
+            }
+
+            [Fact]
+            public void InsertNewFrame_FramesMustHaveSameSize()
+            {
+                ArgumentException ex = Assert.Throws<ArgumentException>(
+                    () =>
+                    {
+                        this.Collection.InsertFrame(1, new ImageFrame<Rgba32>(Configuration.Default, 1, 1));
+                    });
+
+                Assert.StartsWith("Frame must have the same dimensions as the image.", ex.Message);
+            }
+
+            [Fact]
+            public void InsertNewFrame_FramesNotBeNull()
+            {
+                ArgumentNullException ex = Assert.Throws<ArgumentNullException>(
+                    () =>
+                    {
+                        this.Collection.InsertFrame(1, null);
+                    });
+
+                Assert.StartsWith("Value cannot be null.", ex.Message);
+            }
+
+
+            [Fact]
+            public void RemoveAtFrame_ThrowIfRemovingLastFrame()
+            {
+
+                InvalidOperationException ex = Assert.Throws<InvalidOperationException>(
+                    () =>
+                    {
+                        this.Collection.RemoveFrame(0);
+                    });
+                Assert.Equal("Cannot remove last frame.", ex.Message);
+            }
+
+            [Fact]
+            public void RemoveAtFrame_CanRemoveFrameZeroIfMultipleFramesExist()
+            {
+                this.Collection.AddFrame(new ImageFrame<Rgba32>(Configuration.Default, 10, 10));
+
+                this.Collection.RemoveFrame(0);
+                Assert.Equal(1, this.Collection.Count);
+            }
+
+            [Fact]
+            public void RootFrameIsFrameAtIndexZero()
+            {
+                Assert.Equal(this.Collection.RootFrame, this.Collection[0]);
+            }
+
+            [Theory]
+            [WithTestPatternImages(10, 10, PixelTypes.Rgba32 | PixelTypes.Bgr24)]
+            public void CloneFrame<TPixel>(TestImageProvider<TPixel> provider)
+                where TPixel : struct, IPixel<TPixel>
+            {
+                using (Image<TPixel> img = provider.GetImage())
+                {
+                    ImageFrameCollection nonGenericFrameCollection = img.Frames;
+
+                    nonGenericFrameCollection.AddFrame(new ImageFrame<TPixel>(Configuration.Default, 10, 10)); // add a frame anyway
+                    using (Image cloned = nonGenericFrameCollection.CloneFrame(0))
+                    {
+                        Assert.Equal(2, img.Frames.Count);
+
+                        Image<TPixel> expectedClone = (Image<TPixel>)cloned;
+
+                        expectedClone.ComparePixelBufferTo(img.GetPixelSpan());
+                    }
+                }
+            }
+
+            [Theory]
+            [WithTestPatternImages(10, 10, PixelTypes.Rgba32)]
+            public void ExtractFrame<TPixel>(TestImageProvider<TPixel> provider)
+                where TPixel : struct, IPixel<TPixel>
+            {
+                using (Image<TPixel> img = provider.GetImage())
+                {
+                    var sourcePixelData = img.GetPixelSpan().ToArray();
+
+                    ImageFrameCollection nonGenericFrameCollection = img.Frames;
+
+                    nonGenericFrameCollection.AddFrame(new ImageFrame<TPixel>(Configuration.Default, 10, 10));
+                    using (Image cloned = nonGenericFrameCollection.ExportFrame(0))
+                    {
+                        Assert.Equal(1, img.Frames.Count);
+
+                        Image<TPixel> expectedClone = (Image<TPixel>)cloned;
+                        expectedClone.ComparePixelBufferTo(sourcePixelData);
+                    }
+                }
+            }
+
+            [Fact]
+            public void CreateFrame_Default()
+            {
+                this.Image.Frames.CreateFrame();
+
+                Assert.Equal(2, this.Image.Frames.Count);
+
+                ImageFrame<Rgba32> frame = (ImageFrame<Rgba32>)this.Image.Frames[1];
+
+                frame.ComparePixelBufferTo(default(Rgba32));
+            }
+
+            [Fact]
+            public void CreateFrame_CustomFillColor()
+            {
+                this.Image.Frames.CreateFrame(Rgba32.HotPink);
+
+                Assert.Equal(2, this.Image.Frames.Count);
+
+                ImageFrame<Rgba32> frame = (ImageFrame<Rgba32>)this.Image.Frames[1];
+
+                frame.ComparePixelBufferTo(Rgba32.HotPink);
+            }
+
+            [Fact]
+            public void MoveFrame_LeavesFrmaeInCorrectLocation()
+            {
+                for (var i = 0; i < 9; i++)
+                {
+                    this.Image.Frames.CreateFrame();
+                }
+
+                var frame = this.Image.Frames[4];
+                this.Image.Frames.MoveFrame(4, 7);
+                var newIndex = this.Image.Frames.IndexOf(frame);
+                Assert.Equal(7, newIndex);
+            }
+
+            [Fact]
+            public void IndexOf_ReturnsCorrectIndex()
+            {
+                for (var i = 0; i < 9; i++)
+                {
+                    this.Image.Frames.CreateFrame();
+                }
+
+                var frame = this.Image.Frames[4];
+                var index = this.Image.Frames.IndexOf(frame);
+                Assert.Equal(4, index);
+            }
+
+            [Fact]
+            public void Contains_TrueIfMember()
+            {
+                for (var i = 0; i < 9; i++)
+                {
+                    this.Image.Frames.CreateFrame();
+                }
+
+                var frame = this.Image.Frames[4];
+                Assert.True(this.Image.Frames.Contains(frame));
+            }
+
+            [Fact]
+            public void Contains_FalseIfNonMember()
+            {
+                for (var i = 0; i < 9; i++)
+                {
+                    this.Image.Frames.CreateFrame();
+                }
+
+                var frame = new ImageFrame<Rgba32>(Configuration.Default, 10, 10);
+                Assert.False(this.Image.Frames.Contains(frame));
+            }
+
+            /// <summary>
+            /// Integration test for end-to end API validation.
+            /// </summary>
+            [Theory]
+            [WithFile(TestImages.Gif.Giphy, PixelTypes.Rgba32)]
+            public void ConstructGif_FromDifferentPixelTypes<TPixel>(TestImageProvider<TPixel> provider)
+                where TPixel : struct, IPixel<TPixel>
+            {
+                using (Image source = provider.GetImage())
+                using (Image<TPixel> dest = new Image<TPixel>(source.GetConfiguration(), source.Width, source.Height))
+                {
+                    // Giphy.gif has 5 frames
+
+                    ImportFrameAs<Bgra32>(source.Frames, dest.Frames, 0);
+                    ImportFrameAs<Argb32>(source.Frames, dest.Frames, 1);
+                    ImportFrameAs<Rgba64>(source.Frames, dest.Frames, 2);
+                    ImportFrameAs<Rgba32>(source.Frames, dest.Frames, 3);
+                    ImportFrameAs<Bgra32>(source.Frames, dest.Frames, 4);
+
+                    // Drop the original empty root frame:
+                    dest.Frames.RemoveFrame(0);
+
+                    dest.DebugSave(provider, appendSourceFileOrDescription: false, extension: "gif");
+                    dest.CompareToOriginal(provider);
+
+                    for (int i = 0; i < 5; i++)
+                    {
+                        CompareGifMetadata(source.Frames[i], dest.Frames[i]);
+                    }
+                }
+            }
+
+            private static void ImportFrameAs<TPixel>(ImageFrameCollection source, ImageFrameCollection destination, int index)
+                where TPixel : struct, IPixel<TPixel>
+            {
+                using (Image temp = source.CloneFrame(index))
+                {
+                    using (Image<TPixel> temp2 = temp.CloneAs<TPixel>())
+                    {
+                        destination.AddFrame(temp2.Frames.RootFrame);
+                    }
+                }
+            }
+
+            private static void CompareGifMetadata(ImageFrame a, ImageFrame b)
+            {
+                // TODO: all metadata classes should be equatable!
+
+                GifFrameMetadata aData = a.Metadata.GetFormatMetadata(GifFormat.Instance);
+                GifFrameMetadata bData = b.Metadata.GetFormatMetadata(GifFormat.Instance);
+
+                Assert.Equal(aData.DisposalMethod, bData.DisposalMethod);
+                Assert.Equal(aData.FrameDelay, bData.FrameDelay);
+                Assert.Equal(aData.ColorTableLength, bData.ColorTableLength);
+            }
+        }
+    }
+}

tests/ImageSharp.Tests/Image/ImageFrameCollectionTests.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Tests
+{
+    public abstract partial class ImageFrameCollectionTests : IDisposable
+    {
+        protected Image<Rgba32> Image { get; }
+        protected ImageFrameCollection<Rgba32> Collection { get; }
+
+        public ImageFrameCollectionTests()
+        {
+            // Needed to get English exception messages, which are checked in several tests.
+            System.Threading.Thread.CurrentThread.CurrentUICulture = new System.Globalization.CultureInfo("en-US");
+
+            this.Image = new Image<Rgba32>(10, 10);
+            this.Collection = new ImageFrameCollection<Rgba32>(this.Image, 10, 10, default(Rgba32));
+        }
+
+        public void Dispose()
+        {
+            this.Image.Dispose();
+            this.Collection.Dispose();
+        }
+    }
+}

tests/ImageSharp.Tests/Image/ImageFramesCollectionTests.cs

@@ -1,331 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using SixLabors.ImageSharp.Advanced;
-using SixLabors.ImageSharp.PixelFormats;
-using Xunit;
-
-namespace SixLabors.ImageSharp.Tests
-{
-    public class ImageFramesCollectionTests : IDisposable
-    {
-        private Image<Rgba32> image;
-        private ImageFrameCollection<Rgba32> collection;
-
-        public ImageFramesCollectionTests()
-        {
-            // Needed to get English exception messages, which are checked in several tests.
-            System.Threading.Thread.CurrentThread.CurrentUICulture = new System.Globalization.CultureInfo("en-US");
-
-            this.image = new Image<Rgba32>(10, 10);
-            this.collection = new ImageFrameCollection<Rgba32>(this.image, 10, 10, default(Rgba32));
-        }
-
-        [Fact]
-        public void ImageFramesaLwaysHaveOneFrame()
-        {
-            Assert.Equal(1, this.collection.Count);
-        }
-
-        [Fact]
-        public void AddNewFrame_FramesMustHaveSameSize()
-        {
-            ArgumentException ex = Assert.Throws<ArgumentException>(() =>
-            {
-                this.collection.AddFrame(new ImageFrame<Rgba32>(Configuration.Default, 1, 1));
-            });
-
-            Assert.StartsWith("Frame must have the same dimensions as the image.", ex.Message);
-        }
-
-        [Fact]
-        public void AddNewFrame_Frame_FramesNotBeNull()
-        {
-            ArgumentNullException ex = Assert.Throws<ArgumentNullException>(() =>
-            {
-                this.collection.AddFrame((ImageFrame<Rgba32>)null);
-            });
-
-            Assert.StartsWith("Value cannot be null.", ex.Message);
-        }
-
-        [Fact]
-        public void AddNewFrame_PixelBuffer_DataMustNotBeNull()
-        {
-            Rgba32[] data = null;
-
-            ArgumentNullException ex = Assert.Throws<ArgumentNullException>(() =>
-            {
-                this.collection.AddFrame(data);
-            });
-
-            Assert.StartsWith("Value cannot be null.", ex.Message);
-        }
-
-        [Fact]
-        public void AddNewFrame_PixelBuffer_BufferIncorrectSize()
-        {
-            ArgumentOutOfRangeException ex = Assert.Throws<ArgumentOutOfRangeException>(() =>
-            {
-                this.collection.AddFrame(new Rgba32[0]);
-            });
-
-            Assert.StartsWith("Value 0 must be greater than or equal to 100.", ex.Message);
-        }
-
-        [Fact]
-        public void InsertNewFrame_FramesMustHaveSameSize()
-        {
-            ArgumentException ex = Assert.Throws<ArgumentException>(() =>
-            {
-                this.collection.InsertFrame(1, new ImageFrame<Rgba32>(Configuration.Default, 1, 1));
-            });
-
-            Assert.StartsWith("Frame must have the same dimensions as the image.", ex.Message);
-        }
-
-        [Fact]
-        public void InsertNewFrame_FramesNotBeNull()
-        {
-            ArgumentNullException ex = Assert.Throws<ArgumentNullException>(() =>
-            {
-                this.collection.InsertFrame(1, null);
-            });
-
-            Assert.StartsWith("Value cannot be null.", ex.Message);
-        }
-
-        [Fact]
-        public void Constructor_FramesMustHaveSameSize()
-        {
-            ArgumentException ex = Assert.Throws<ArgumentException>(() =>
-            {
-                var collection = new ImageFrameCollection<Rgba32>(this.image, new[] {
-                    new ImageFrame<Rgba32>(Configuration.Default,10,10),
-                    new ImageFrame<Rgba32>(Configuration.Default,1,1)
-                });
-            });
-
-            Assert.StartsWith("Frame must have the same dimensions as the image.", ex.Message);
-        }
-
-        [Fact]
-        public void RemoveAtFrame_ThrowIfRemovingLastFrame()
-        {
-            var collection = new ImageFrameCollection<Rgba32>(this.image, new[] {
-                    new ImageFrame<Rgba32>(Configuration.Default,10,10)
-                });
-
-            InvalidOperationException ex = Assert.Throws<InvalidOperationException>(() =>
-            {
-                collection.RemoveFrame(0);
-            });
-            Assert.Equal("Cannot remove last frame.", ex.Message);
-        }
-
-        [Fact]
-        public void RemoveAtFrame_CanRemoveFrameZeroIfMultipleFramesExist()
-        {
-
-            var collection = new ImageFrameCollection<Rgba32>(this.image, new[] {
-                    new ImageFrame<Rgba32>(Configuration.Default,10,10),
-                    new ImageFrame<Rgba32>(Configuration.Default,10,10)
-                });
-
-            collection.RemoveFrame(0);
-            Assert.Equal(1, collection.Count);
-        }
-
-        [Fact]
-        public void RootFrameIsFrameAtIndexZero()
-        {
-            var collection = new ImageFrameCollection<Rgba32>(this.image, new[] {
-                new ImageFrame<Rgba32>(Configuration.Default,10,10),
-                new ImageFrame<Rgba32>(Configuration.Default,10,10)
-            });
-
-            Assert.Equal(collection.RootFrame, collection[0]);
-        }
-
-        [Fact]
-        public void ConstructorPopulatesFrames()
-        {
-            var collection = new ImageFrameCollection<Rgba32>(this.image, new[] {
-                new ImageFrame<Rgba32>(Configuration.Default,10,10),
-                new ImageFrame<Rgba32>(Configuration.Default,10,10)
-            });
-
-            Assert.Equal(2, collection.Count);
-        }
-
-        [Fact]
-        public void DisposeClearsCollection()
-        {
-            var collection = new ImageFrameCollection<Rgba32>(this.image, new[] {
-                new ImageFrame<Rgba32>(Configuration.Default,10,10),
-                new ImageFrame<Rgba32>(Configuration.Default,10,10)
-            });
-
-            collection.Dispose();
-
-            Assert.Equal(0, collection.Count);
-        }
-
-        [Fact]
-        public void Dispose_DisposesAllInnerFrames()
-        {
-            var collection = new ImageFrameCollection<Rgba32>(this.image, new[] {
-                new ImageFrame<Rgba32>(Configuration.Default,10,10),
-                new ImageFrame<Rgba32>(Configuration.Default,10,10)
-            });
-
-            IPixelSource<Rgba32>[] framesSnapShot = collection.OfType<IPixelSource<Rgba32>>().ToArray();
-            collection.Dispose();
-
-            Assert.All(framesSnapShot, f =>
-            {
-                // the pixel source of the frame is null after its been disposed.
-                Assert.Null(f.PixelBuffer);
-            });
-        }
-
-        [Theory]
-        [WithTestPatternImages(10, 10, PixelTypes.Rgba32)]
-        public void CloneFrame<TPixel>(TestImageProvider<TPixel> provider)
-           where TPixel : struct, IPixel<TPixel>
-        {
-            using (Image<TPixel> img = provider.GetImage())
-            {
-                img.Frames.AddFrame(new ImageFrame<TPixel>(Configuration.Default, 10, 10));// add a frame anyway
-                using (Image<TPixel> cloned = img.Frames.CloneFrame(0))
-                {
-                    Assert.Equal(2, img.Frames.Count);
-                    cloned.ComparePixelBufferTo(img.GetPixelSpan());
-                }
-            }
-        }
-
-        [Theory]
-        [WithTestPatternImages(10, 10, PixelTypes.Rgba32)]
-        public void ExtractFrame<TPixel>(TestImageProvider<TPixel> provider)
-            where TPixel : struct, IPixel<TPixel>
-        {
-            using (Image<TPixel> img = provider.GetImage())
-            {
-                var sourcePixelData = img.GetPixelSpan().ToArray();
-
-                img.Frames.AddFrame(new ImageFrame<TPixel>(Configuration.Default, 10, 10));
-                using (Image<TPixel> cloned = img.Frames.ExportFrame(0))
-                {
-                    Assert.Equal(1, img.Frames.Count);
-                    cloned.ComparePixelBufferTo(sourcePixelData);
-                }
-            }
-        }
-
-        [Fact]
-        public void CreateFrame_Default()
-        {
-            this.image.Frames.CreateFrame();
-
-            Assert.Equal(2, this.image.Frames.Count);
-            this.image.Frames[1].ComparePixelBufferTo(default(Rgba32));
-        }
-
-        [Fact]
-        public void CreateFrame_CustomFillColor()
-        {
-            this.image.Frames.CreateFrame(Rgba32.HotPink);
-
-            Assert.Equal(2, this.image.Frames.Count);
-            this.image.Frames[1].ComparePixelBufferTo(Rgba32.HotPink);
-        }
-
-        [Fact]
-        public void AddFrameFromPixelData()
-        {
-            var pixelData = this.image.Frames.RootFrame.GetPixelSpan().ToArray();
-            this.image.Frames.AddFrame(pixelData);
-            Assert.Equal(2, this.image.Frames.Count);
-        }
-
-        [Fact]
-        public void AddFrame_clones_sourceFrame()
-        {
-            var pixelData = this.image.Frames.RootFrame.GetPixelSpan().ToArray();
-            var otherFRame = new ImageFrame<Rgba32>(Configuration.Default, 10, 10);
-            var addedFrame = this.image.Frames.AddFrame(otherFRame);
-            addedFrame.ComparePixelBufferTo(otherFRame.GetPixelSpan());
-            Assert.NotEqual(otherFRame, addedFrame);
-        }
-
-        [Fact]
-        public void InsertFrame_clones_sourceFrame()
-        {
-            var pixelData = this.image.Frames.RootFrame.GetPixelSpan().ToArray();
-            var otherFRame = new ImageFrame<Rgba32>(Configuration.Default, 10, 10);
-            var addedFrame = this.image.Frames.InsertFrame(0, otherFRame);
-            addedFrame.ComparePixelBufferTo(otherFRame.GetPixelSpan());
-            Assert.NotEqual(otherFRame, addedFrame);
-        }
-
-        [Fact]
-        public void MoveFrame_LeavesFrmaeInCorrectLocation()
-        {
-            for (var i = 0; i < 9; i++)
-            {
-                this.image.Frames.CreateFrame();
-            }
-
-            var frame = this.image.Frames[4];
-            this.image.Frames.MoveFrame(4, 7);
-            var newIndex = this.image.Frames.IndexOf(frame);
-            Assert.Equal(7, newIndex);
-        }
-
-
-        [Fact]
-        public void IndexOf_ReturnsCorrectIndex()
-        {
-            for (var i = 0; i < 9; i++)
-            {
-                this.image.Frames.CreateFrame();
-            }
-
-            var frame = this.image.Frames[4];
-            var index = this.image.Frames.IndexOf(frame);
-            Assert.Equal(4, index);
-        }
-
-        [Fact]
-        public void Contains_TrueIfMember()
-        {
-            for (var i = 0; i < 9; i++)
-            {
-                this.image.Frames.CreateFrame();
-            }
-
-            var frame = this.image.Frames[4];
-            Assert.True(this.image.Frames.Contains(frame));
-        }
-
-        [Fact]
-        public void Contains_TFalseIfNoneMember()
-        {
-            for (var i = 0; i < 9; i++)
-            {
-                this.image.Frames.CreateFrame();
-            }
-
-            var frame = new ImageFrame<Rgba32>(Configuration.Default, 10, 10);
-            Assert.False(this.image.Frames.Contains(frame));
-        }
-
-        public void Dispose()
-        {
-            this.image.Dispose();
-            this.collection.Dispose();
-        }
-    }
-}

tests/ImageSharp.Tests/ImageSharp.Tests.csproj

@@ -2,6 +2,13 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
+    <TargetFrameworks>netcoreapp2.1;net462;net472</TargetFrameworks>
+    <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
+    <LangVersion>latest</LangVersion>
+    <DebugType Condition="$(codecov) != ''">full</DebugType>
+    <DebugType Condition="$(codecov) == ''">portable</DebugType>
+    <DebugSymbols>True</DebugSymbols>
+    <RootNamespace>SixLabors.ImageSharp.Tests</RootNamespace>
     <AssemblyName>SixLabors.ImageSharp.Tests</AssemblyName>
     <Platforms>AnyCPU;x64;x86</Platforms>
     <RootNamespace>SixLabors.ImageSharp.Tests</RootNamespace>

tests/ImageSharp.Tests/PixelFormats/PixelConverterTests.ReferenceImplementations.cs

@@ -0,0 +1,115 @@
+// // Copyright (c) Six Labors and contributors.
+// // Licensed under the Apache License, Version 2.0.
+
+// // Copyright (c) Six Labors and contributors.
+// // Licensed under the Apache License, Version 2.0.
+
+// // Copyright (c) Six Labors and contributors.
+// // Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Tests.PixelFormats
+{
+    public abstract partial class PixelConverterTests
+    {
+        public static class ReferenceImplementations
+        {
+            public static Rgba32 MakeRgba32(byte r, byte g, byte b, byte a)
+            {
+                Rgba32 d = default;
+                d.R = r;
+                d.G = g;
+                d.B = b;
+                d.A = a;
+                return d;
+            }
+
+            public static Argb32 MakeArgb32(byte r, byte g, byte b, byte a)
+            {
+                Argb32 d = default;
+                d.R = r;
+                d.G = g;
+                d.B = b;
+                d.A = a;
+                return d;
+            }
+
+            public static Bgra32 MakeBgra32(byte r, byte g, byte b, byte a)
+            {
+                Bgra32 d = default;
+                d.R = r;
+                d.G = g;
+                d.B = b;
+                d.A = a;
+                return d;
+            }
+
+            internal static void To<TSourcePixel, TDestinationPixel>(
+                Configuration configuration,
+                ReadOnlySpan<TSourcePixel> sourcePixels,
+                Span<TDestinationPixel> destinationPixels)
+                where TSourcePixel : struct, IPixel<TSourcePixel> where TDestinationPixel : struct, IPixel<TDestinationPixel>
+            {
+                Guard.NotNull(configuration, nameof(configuration));
+                Guard.DestinationShouldNotBeTooShort(sourcePixels, destinationPixels, nameof(destinationPixels));
+
+                int count = sourcePixels.Length;
+                ref TSourcePixel sourceRef = ref MemoryMarshal.GetReference(sourcePixels);
+
+                if (typeof(TSourcePixel) == typeof(TDestinationPixel))
+                {
+                    Span<TSourcePixel> uniformDest =
+                        MemoryMarshal.Cast<TDestinationPixel, TSourcePixel>(destinationPixels);
+                    sourcePixels.CopyTo(uniformDest);
+                    return;
+                }
+
+                // Gray8 and Gray16 are special implementations of IPixel in that they do not conform to the
+                // standard RGBA colorspace format and must be converted from RGBA using the special ITU BT709 algorithm.
+                // One of the requirements of FromScaledVector4/ToScaledVector4 is that it unaware of this and
+                // packs/unpacks the pixel without and conversion so we employ custom methods do do this.
+                if (typeof(TDestinationPixel) == typeof(Gray16))
+                {
+                    ref Gray16 gray16Ref = ref MemoryMarshal.GetReference(
+                                               MemoryMarshal.Cast<TDestinationPixel, Gray16>(destinationPixels));
+                    for (int i = 0; i < count; i++)
+                    {
+                        ref TSourcePixel sp = ref Unsafe.Add(ref sourceRef, i);
+                        ref Gray16 dp = ref Unsafe.Add(ref gray16Ref, i);
+                        dp.ConvertFromRgbaScaledVector4(sp.ToScaledVector4());
+                    }
+
+                    return;
+                }
+
+                if (typeof(TDestinationPixel) == typeof(Gray8))
+                {
+                    ref Gray8 gray8Ref = ref MemoryMarshal.GetReference(
+                                             MemoryMarshal.Cast<TDestinationPixel, Gray8>(destinationPixels));
+                    for (int i = 0; i < count; i++)
+                    {
+                        ref TSourcePixel sp = ref Unsafe.Add(ref sourceRef, i);
+                        ref Gray8 dp = ref Unsafe.Add(ref gray8Ref, i);
+                        dp.ConvertFromRgbaScaledVector4(sp.ToScaledVector4());
+                    }
+
+                    return;
+                }
+
+                // Normal conversion
+                ref TDestinationPixel destRef = ref MemoryMarshal.GetReference(destinationPixels);
+                for (int i = 0; i < count; i++)
+                {
+                    ref TSourcePixel sp = ref Unsafe.Add(ref sourceRef, i);
+                    ref TDestinationPixel dp = ref Unsafe.Add(ref destRef, i);
+                    dp.FromScaledVector4(sp.ToScaledVector4());
+                }
+            }
+        }
+    }
+}

tests/ImageSharp.Tests/PixelFormats/PixelConverterTests.cs

@@ -5,7 +5,7 @@ using Xunit;
 
 namespace SixLabors.ImageSharp.Tests.PixelFormats
 {
-    public abstract class PixelConverterTests
+    public abstract partial class PixelConverterTests
     {
         public static readonly TheoryData<byte, byte, byte, byte> RgbaData =
             new TheoryData<byte, byte, byte, byte>
@@ -122,39 +122,5 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats
                 Assert.Equal(expectedPacked, actualPacked);
             }
         }
-
-
-        private static class ReferenceImplementations
-        {
-            public static Rgba32 MakeRgba32(byte r, byte g, byte b, byte a)
-            {
-                Rgba32 d = default;
-                d.R = r;
-                d.G = g;
-                d.B = b;
-                d.A = a;
-                return d;
-            }
-
-            public static Argb32 MakeArgb32(byte r, byte g, byte b, byte a)
-            {
-                Argb32 d = default;
-                d.R = r;
-                d.G = g;
-                d.B = b;
-                d.A = a;
-                return d;
-            }
-
-            public static Bgra32 MakeBgra32(byte r, byte g, byte b, byte a)
-            {
-                Bgra32 d = default;
-                d.R = r;
-                d.G = g;
-                d.B = b;
-                d.A = a;
-                return d;
-            }
-        }
     }
-}
+}

tests/ImageSharp.Tests/PixelFormats/PixelOperations/PixelOperationsTests.Bgra5551OperationsTests.cs

@@ -0,0 +1,20 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using SixLabors.ImageSharp.PixelFormats;
+
+using Xunit.Abstractions;
+
+namespace SixLabors.ImageSharp.Tests.PixelFormats.PixelOperations
+{
+    public partial class PixelOperationsTests
+    {
+        public class Bgra5551OperationsTests : PixelOperationsTests<Bgra5551>
+        {
+            public Bgra5551OperationsTests(ITestOutputHelper output)
+                : base(output)
+            {
+            }
+        }
+    }
+}

tests/ImageSharp.Tests/PixelFormats/PixelOperations/PixelOperationsTests.Gray16OperationsTests.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
+using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
@@ -25,90 +26,6 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats.PixelOperations
             [Fact]
             public void IsSpecialImplementation() => Assert.IsType<Gray16.PixelOperations>(PixelOperations<Gray16>.Instance);
 
-            [Theory]
-            [MemberData(nameof(ArraySizesData))]
-            public void FromGray8Bytes(int count)
-            {
-                byte[] source = CreateByteTestData(count);
-                var expected = new Gray16[count];
-
-                for (int i = 0; i < count; i++)
-                {
-                    expected[i].FromGray8(new Gray8(source[i]));
-                }
-
-                TestOperation(
-                    source,
-                    expected,
-                    (s, d) => Operations.FromGray8Bytes(this.Configuration, s, d.GetSpan(), count)
-                );
-            }
-
-            [Theory]
-            [MemberData(nameof(ArraySizesData))]
-            public void ToGray8Bytes(int count)
-            {
-                Gray16[] source = CreatePixelTestData(count);
-                byte[] expected = new byte[count];
-                var gray = default(Gray8);
-
-                for (int i = 0; i < count; i++)
-                {
-                    gray.FromScaledVector4(source[i].ToScaledVector4());
-                    expected[i] = gray.PackedValue;
-                }
-
-                TestOperation(
-                    source,
-                    expected,
-                    (s, d) => Operations.ToGray8Bytes(this.Configuration, s, d.GetSpan(), count)
-                );
-            }
-
-            [Theory]
-            [MemberData(nameof(ArraySizesData))]
-            public void FromGray16Bytes(int count)
-            {
-                byte[] source = CreateByteTestData(count * 2);
-                Span<byte> sourceSpan = source.AsSpan();
-                var expected = new Gray16[count];
-
-                for (int i = 0; i < count; i++)
-                {
-                    int i2 = i * 2;
-                    expected[i].FromGray16(MemoryMarshal.Cast<byte, Gray16>(sourceSpan.Slice(i2, 2))[0]);
-                }
-
-                TestOperation(
-                    source,
-                    expected,
-                    (s, d) => Operations.FromGray16Bytes(this.Configuration, s, d.GetSpan(), count)
-                );
-            }
-
-            [Theory]
-            [MemberData(nameof(ArraySizesData))]
-            public void ToGray16Bytes(int count)
-            {
-                Gray16[] source = CreatePixelTestData(count);
-                byte[] expected = new byte[count * 2];
-                Gray16 gray = default;
-
-                for (int i = 0; i < count; i++)
-                {
-                    int i2 = i * 2;
-                    gray.FromScaledVector4(source[i].ToScaledVector4());
-                    OctetBytes bytes = Unsafe.As<Gray16, OctetBytes>(ref gray);
-                    expected[i2] = bytes[0];
-                    expected[i2 + 1] = bytes[1];
-                }
-
-                TestOperation(
-                    source,
-                    expected,
-                    (s, d) => Operations.ToGray16Bytes(this.Configuration, s, d.GetSpan(), count)
-                );
-            }
         }
     }
-}
+}

tests/ImageSharp.Tests/PixelFormats/PixelOperations/PixelOperationsTests.Gray8OperationsTests.cs

@@ -24,91 +24,6 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats.PixelOperations
 
             [Fact]
             public void IsSpecialImplementation() => Assert.IsType<Gray8.PixelOperations>(PixelOperations<Gray8>.Instance);
-
-            [Theory]
-            [MemberData(nameof(ArraySizesData))]
-            public void FromGray8Bytes(int count)
-            {
-                byte[] source = CreateByteTestData(count);
-                var expected = new Gray8[count];
-
-                for (int i = 0; i < count; i++)
-                {
-                    expected[i].FromGray8(new Gray8(source[i]));
-                }
-
-                TestOperation(
-                    source,
-                    expected,
-                    (s, d) => Operations.FromGray8Bytes(this.Configuration, s, d.GetSpan(), count)
-                );
-            }
-
-            [Theory]
-            [MemberData(nameof(ArraySizesData))]
-            public void ToGray8Bytes(int count)
-            {
-                Gray8[] source = CreatePixelTestData(count);
-                byte[] expected = new byte[count];
-                var gray = default(Gray8);
-
-                for (int i = 0; i < count; i++)
-                {
-                    gray.FromScaledVector4(source[i].ToScaledVector4());
-                    expected[i] = gray.PackedValue;
-                }
-
-                TestOperation(
-                    source,
-                    expected,
-                    (s, d) => Operations.ToGray8Bytes(this.Configuration, s, d.GetSpan(), count)
-                );
-            }
-
-            [Theory]
-            [MemberData(nameof(ArraySizesData))]
-            public void FromGray16Bytes(int count)
-            {
-                byte[] source = CreateByteTestData(count * 2);
-                Span<byte> sourceSpan = source.AsSpan();
-                var expected = new Gray8[count];
-
-                for (int i = 0; i < count; i++)
-                {
-                    int i2 = i * 2;
-                    expected[i].FromGray16(MemoryMarshal.Cast<byte, Gray16>(sourceSpan.Slice(i2, 2))[0]);
-                }
-
-                TestOperation(
-                    source,
-                    expected,
-                    (s, d) => Operations.FromGray16Bytes(this.Configuration, s, d.GetSpan(), count)
-                );
-            }
-
-            [Theory]
-            [MemberData(nameof(ArraySizesData))]
-            public void ToGray16Bytes(int count)
-            {
-                Gray8[] source = CreatePixelTestData(count);
-                byte[] expected = new byte[count * 2];
-                Gray16 gray = default;
-
-                for (int i = 0; i < count; i++)
-                {
-                    int i2 = i * 2;
-                    gray.FromScaledVector4(source[i].ToScaledVector4());
-                    OctetBytes bytes = Unsafe.As<Gray16, OctetBytes>(ref gray);
-                    expected[i2] = bytes[0];
-                    expected[i2 + 1] = bytes[1];
-                }
-
-                TestOperation(
-                    source,
-                    expected,
-                    (s, d) => Operations.ToGray16Bytes(this.Configuration, s, d.GetSpan(), count)
-                );
-            }
         }
     }
-}
+}

tests/ImageSharp.Tests/PixelFormats/PixelOperations/PixelOperationsTests.Rgb24OperationsTests.cs

@@ -21,4 +21,4 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats.PixelOperations
             public void IsSpecialImplementation() => Assert.IsType<Rgb24.PixelOperations>(PixelOperations<Rgb24>.Instance);
         }
     }
-}
+}

tests/ImageSharp.Tests/PixelFormats/PixelOperations/PixelOperationsTests.cs

@@ -3,12 +3,14 @@
 
 using System;
 using System.Buffers;
+using System.Linq;
 using System.Numerics;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using SixLabors.ImageSharp.ColorSpaces.Companding;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Tests.Formats.Jpg.Utils;
 
 using Xunit;
 using Xunit.Abstractions;
@@ -245,7 +247,7 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats.PixelOperations
                 {
                     Vector4Utils.UnPremultiply(ref v);
                 }
-                
+
                 SRgbCompanding.Compress(ref v);
             }
 
@@ -277,6 +279,33 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats.PixelOperations
             );
         }
 
+
+        public static readonly TheoryData<IPixel> Generic_To_Data = new TheoryData<IPixel>
+                                                    {
+                                                        default(Rgba32),
+                                                        default(Bgra32),
+                                                        default(Rgb24),
+                                                        default(Gray8),
+                                                        default(Gray16),
+                                                        default(Rgb48),
+                                                        default(Rgba64)
+                                                    };
+
+        [Theory]
+        [MemberData(nameof(Generic_To_Data))]
+        public void Generic_To<TDestPixel>(TDestPixel dummy)
+            where TDestPixel : struct, IPixel<TDestPixel>
+        {
+            const int Count = 2134;
+            TPixel[] source = CreatePixelTestData(Count);
+            TDestPixel[] expected = new TDestPixel[Count];
+
+            PixelConverterTests.ReferenceImplementations.To<TPixel, TDestPixel>(this.Configuration, source, expected);
+
+            TestOperation(source, expected, (s, d) => Operations.To(this.Configuration, (ReadOnlySpan<TPixel>)s, d.GetSpan()));
+        }
+
+
         [Theory]
         [MemberData(nameof(ArraySizesData))]
         public void ToScaledVector4(int count)
@@ -732,6 +761,92 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats.PixelOperations
             );
         }
 
+
+            [Theory]
+            [MemberData(nameof(ArraySizesData))]
+            public void FromGray8(int count)
+            {
+                byte[] sourceBytes = CreateByteTestData(count);
+                Gray8[] source = sourceBytes.Select(b => new Gray8(b)).ToArray();
+                var expected = new TPixel[count];
+
+
+                for (int i = 0; i < count; i++)
+                {
+                    expected[i].FromGray8(source[i]);
+                }
+
+                TestOperation(
+                    source,
+                    expected,
+                    (s, d) => Operations.FromGray8(this.Configuration, s, d.GetSpan())
+                );
+            }
+
+            [Theory]
+            [MemberData(nameof(ArraySizesData))]
+            public void ToGray8(int count)
+            {
+                TPixel[] source = CreatePixelTestData(count);
+                Gray8[] expected = new Gray8[count];
+
+                for (int i = 0; i < count; i++)
+                {
+                    expected[i].FromScaledVector4(source[i].ToScaledVector4());
+                }
+
+                TestOperation(
+                    source,
+                    expected,
+                    (s, d) => Operations.ToGray8(this.Configuration, s, d.GetSpan())
+                );
+            }
+
+            [Theory]
+            [MemberData(nameof(ArraySizesData))]
+            public void FromGray16(int count)
+            {
+                Gray16[] source = CreateVector4TestData(count).Select(v =>
+                {
+                    Gray16 g = default;
+                    g.FromVector4(v);
+                    return g;
+                }).ToArray();
+
+                var expected = new TPixel[count];
+
+                for (int i = 0; i < count; i++)
+                {
+                    int i2 = i * 2;
+                    expected[i].FromGray16(source[i]);
+                }
+
+                TestOperation(
+                    source,
+                    expected,
+                    (s, d) => Operations.FromGray16(this.Configuration, s, d.GetSpan())
+                );
+            }
+
+            [Theory]
+            [MemberData(nameof(ArraySizesData))]
+            public void ToGray16(int count)
+            {
+                TPixel[] source = CreatePixelTestData(count);
+                Gray16[] expected = new Gray16[count];
+
+                for (int i = 0; i < count; i++)
+                {
+                    expected[i].FromScaledVector4(source[i].ToScaledVector4());
+                }
+
+                TestOperation(
+                    source,
+                    expected,
+                    (s, d) => Operations.ToGray16(this.Configuration, s, d.GetSpan())
+                );
+            }
+
         public delegate void RefAction<T1>(ref T1 arg1);
 
         internal static Vector4[] CreateExpectedVector4Data(TPixel[] source, RefAction<Vector4> vectorModifier = null)
@@ -903,6 +1018,18 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats.PixelOperations
                         // ReSharper restore PossibleNullReferenceException
                     }
                 }
+                else if (typeof(TDest) == typeof(Gray16))
+                {
+                    // Minor difference is tolerated for 16 bit pixel values
+                    Span<Gray16> expected = MemoryMarshal.Cast<TDest, Gray16>(this.ExpectedDestBuffer.AsSpan());
+                    Span<Gray16> actual = MemoryMarshal.Cast<TDest, Gray16>(this.ActualDestBuffer.GetSpan());
+
+                    for (int i = 0; i < count; i++)
+                    {
+                        int difference = expected[i].PackedValue - actual[i].PackedValue;
+                        Assert.True(Math.Abs(difference) < 2);
+                    }
+                }
                 else
                 {
                     Span<TDest> expected = this.ExpectedDestBuffer.AsSpan();
@@ -915,4 +1042,4 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats.PixelOperations
             }
         }
     }
-}
+}