From 89348379adf06c661294d00cd9989b4410af7299 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Wed, 9 May 2018 15:42:48 -0700
Subject: [PATCH 01/21] Expose LoadPixelData overloads accepting Span<T>

---
 src/ImageSharp/Image.LoadPixelData.cs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/ImageSharp/Image.LoadPixelData.cs b/src/ImageSharp/Image.LoadPixelData.cs
index 0179e62ac..5f85d61ba 100644
--- a/src/ImageSharp/Image.LoadPixelData.cs
+++ b/src/ImageSharp/Image.LoadPixelData.cs
@@ -33,7 +33,7 @@ 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>
-        private static Image<TPixel> LoadPixelData<TPixel>(Span<TPixel> data, int width, int height)
+        public static Image<TPixel> LoadPixelData<TPixel>(Span<TPixel> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
             => LoadPixelData(Configuration.Default, data, width, height);
 
@@ -57,7 +57,7 @@ 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>
-        private static Image<TPixel> LoadPixelData<TPixel>(Span<byte> data, int width, int height)
+        public static Image<TPixel> LoadPixelData<TPixel>(Span<byte> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
             => LoadPixelData<TPixel>(Configuration.Default, data, width, height);
 
@@ -83,7 +83,7 @@ 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>
-        private static Image<TPixel> LoadPixelData<TPixel>(Configuration config, Span<byte> data, int width, int height)
+        public static Image<TPixel> LoadPixelData<TPixel>(Configuration config, Span<byte> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
             => LoadPixelData(config, MemoryMarshal.Cast<byte, TPixel>(data), width, height);
 
@@ -111,7 +111,7 @@ 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>
-        private static Image<TPixel> LoadPixelData<TPixel>(Configuration config, Span<TPixel> data, int width, int height)
+        public static Image<TPixel> LoadPixelData<TPixel>(Configuration config, Span<TPixel> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
         {
             int count = width * height;

From 052dbdc6a9bda000ddb881d6c4b45d951a5747ba Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Wed, 9 May 2018 16:21:45 -0700
Subject: [PATCH 02/21] Cleanup ByteExtensions

---
 .../Common/Extensions/ByteExtensions.cs       | 35 ++-----------------
 src/ImageSharp/Formats/Gif/GifDecoderCore.cs  |  2 +-
 src/ImageSharp/Formats/Png/PngDecoderCore.cs  | 12 ++++---
 3 files changed, 11 insertions(+), 38 deletions(-)

diff --git a/src/ImageSharp/Common/Extensions/ByteExtensions.cs b/src/ImageSharp/Common/Extensions/ByteExtensions.cs
index b5b868dea..ec53063e6 100644
--- a/src/ImageSharp/Common/Extensions/ByteExtensions.cs
+++ b/src/ImageSharp/Common/Extensions/ByteExtensions.cs
@@ -12,44 +12,15 @@ namespace SixLabors.ImageSharp
     /// </summary>
     internal static class ByteExtensions
     {
-        /// <summary>
-        /// Returns a reference to the given position of the array unsafe casted to <see cref="ImageSharp.PixelFormats.Rgb24"/>.
-        /// </summary>
-        /// <param name="bytes">The byte array.</param>
-        /// <param name="offset">The offset in bytes.</param>
-        /// <returns>The <see cref="ImageSharp.PixelFormats.Rgb24"/> reference at the given offset.</returns>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static ref Rgb24 GetRgb24(this byte[] bytes, int offset)
-        {
-            DebugGuard.MustBeLessThan(offset + 2, bytes.Length, nameof(offset));
-
-            return ref Unsafe.As<byte, Rgb24>(ref bytes[offset]);
-        }
-
         /// <summary>
         /// Returns a reference to the given position of the span unsafe casted to <see cref="ImageSharp.PixelFormats.Rgb24"/>.
         /// </summary>
         /// <param name="bytes">The byte span.</param>
-        /// <param name="offset">The offset in bytes.</param>
-        /// <returns>The <see cref="ImageSharp.PixelFormats.Rgb24"/> reference at the given offset.</returns>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static ref Rgb24 GetRgb24(this Span<byte> bytes, int offset)
-        {
-            DebugGuard.MustBeLessThan(offset + 2, bytes.Length, nameof(offset));
-
-            return ref Unsafe.As<byte, Rgb24>(ref bytes[offset]);
-        }
-
-        /// <summary>
-        ///  Returns a reference to the given position of the buffer pointed by `baseRef` unsafe casted to <see cref="ImageSharp.PixelFormats.Rgb24"/>.
-        /// </summary>
-        /// <param name="baseRef">A reference to the beginning of the buffer</param>
-        /// <param name="offset">The offset in bytes.</param>
         /// <returns>The <see cref="ImageSharp.PixelFormats.Rgb24"/> reference at the given offset.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static ref Rgb24 GetRgb24(ref byte baseRef, int offset)
+        public static ref Rgb24 AsRgb24(this Span<byte> bytes)
         {
-            return ref Unsafe.As<byte, Rgb24>(ref Unsafe.Add(ref baseRef, offset));
-        }
+            return ref Unsafe.As<byte, Rgb24>(ref bytes[0]);
+        }     
     }
 }
\ No newline at end of file
diff --git a/src/ImageSharp/Formats/Gif/GifDecoderCore.cs b/src/ImageSharp/Formats/Gif/GifDecoderCore.cs
index 1900d0df0..6c03bd2b1 100644
--- a/src/ImageSharp/Formats/Gif/GifDecoderCore.cs
+++ b/src/ImageSharp/Formats/Gif/GifDecoderCore.cs
@@ -461,7 +461,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
                         int indexOffset = index * 3;
 
                         ref TPixel pixel = ref Unsafe.Add(ref rowRef, x);
-                        rgba.Rgb = colorTable.GetRgb24(indexOffset);
+                        rgba.Rgb = colorTable.Slice(indexOffset).AsRgb24();
 
                         pixel.PackFromRgba32(rgba);
                     }
diff --git a/src/ImageSharp/Formats/Png/PngDecoderCore.cs b/src/ImageSharp/Formats/Png/PngDecoderCore.cs
index 8fefcb480..20a650e1f 100644
--- a/src/ImageSharp/Formats/Png/PngDecoderCore.cs
+++ b/src/ImageSharp/Formats/Png/PngDecoderCore.cs
@@ -853,7 +853,7 @@ namespace SixLabors.ImageSharp.Formats.Png
             where TPixel : struct, IPixel<TPixel>
         {
             ReadOnlySpan<byte> newScanline = ToArrayByBitsLength(defilteredScanline, this.bytesPerScanline, this.header.BitDepth);
-            byte[] pal = this.palette;
+            Span<byte> pal = this.palette;
             var color = default(TPixel);
 
             var rgba = default(Rgba32);
@@ -868,7 +868,7 @@ namespace SixLabors.ImageSharp.Formats.Png
                     int pixelOffset = index * 3;
 
                     rgba.A = this.paletteAlpha.Length > index ? this.paletteAlpha[index] : (byte)255;
-                    rgba.Rgb = pal.GetRgb24(pixelOffset);
+                    rgba.Rgb = pal.Slice(pixelOffset).AsRgb24();
 
                     color.PackFromRgba32(rgba);
                     row[x] = color;
@@ -883,7 +883,7 @@ namespace SixLabors.ImageSharp.Formats.Png
                     int index = newScanline[x];
                     int pixelOffset = index * 3;
 
-                    rgba.Rgb = pal.GetRgb24(pixelOffset);
+                    rgba.Rgb = pal.Slice(pixelOffset).AsRgb24();
 
                     color.PackFromRgba32(rgba);
                     row[x] = color;
@@ -946,9 +946,11 @@ namespace SixLabors.ImageSharp.Formats.Png
 
                     ReadOnlySpan<byte> newScanline = ToArrayByBitsLength(scanlineBuffer, this.bytesPerScanline, this.header.BitDepth);
                     var rgba = default(Rgba32);
+                    Span<byte> pal = this.palette;
 
                     if (this.paletteAlpha != null && this.paletteAlpha.Length > 0)
                     {
+
                         // If the alpha palette is not null and has one or more entries, this means, that the image contains an alpha
                         // channel and we should try to read it.
                         for (int x = pixelOffset, o = 0; x < this.header.Width; x += increment, o++)
@@ -957,7 +959,7 @@ namespace SixLabors.ImageSharp.Formats.Png
                             int offset = index * 3;
 
                             rgba.A = this.paletteAlpha.Length > index ? this.paletteAlpha[index] : (byte)255;
-                            rgba.Rgb = this.palette.GetRgb24(offset);
+                            rgba.Rgb = pal.Slice(offset).AsRgb24();
 
                             color.PackFromRgba32(rgba);
                             rowSpan[x] = color;
@@ -972,7 +974,7 @@ namespace SixLabors.ImageSharp.Formats.Png
                             int index = newScanline[o];
                             int offset = index * 3;
 
-                            rgba.Rgb = this.palette.GetRgb24(offset);
+                            rgba.Rgb = pal.Slice(offset).AsRgb24();
 
                             color.PackFromRgba32(rgba);
                             rowSpan[x] = color;

From d590008880190333fdd09c248e1f0fdaf6266924 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Wed, 9 May 2018 16:22:28 -0700
Subject: [PATCH 03/21] Remove trailing whitespace

---
 src/ImageSharp/Common/Extensions/ByteExtensions.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ImageSharp/Common/Extensions/ByteExtensions.cs b/src/ImageSharp/Common/Extensions/ByteExtensions.cs
index ec53063e6..ee41096cf 100644
--- a/src/ImageSharp/Common/Extensions/ByteExtensions.cs
+++ b/src/ImageSharp/Common/Extensions/ByteExtensions.cs
@@ -21,6 +21,6 @@ namespace SixLabors.ImageSharp
         public static ref Rgb24 AsRgb24(this Span<byte> bytes)
         {
             return ref Unsafe.As<byte, Rgb24>(ref bytes[0]);
-        }     
+        }
     }
 }
\ No newline at end of file

From 049988669bfbf80562567547916edeb955ee6a2e Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Wed, 9 May 2018 16:37:10 -0700
Subject: [PATCH 04/21] Simplify png decoder

---
 src/ImageSharp/Formats/Png/PngDecoderCore.cs | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/src/ImageSharp/Formats/Png/PngDecoderCore.cs b/src/ImageSharp/Formats/Png/PngDecoderCore.cs
index 20a650e1f..b89c655c8 100644
--- a/src/ImageSharp/Formats/Png/PngDecoderCore.cs
+++ b/src/ImageSharp/Formats/Png/PngDecoderCore.cs
@@ -853,7 +853,7 @@ namespace SixLabors.ImageSharp.Formats.Png
             where TPixel : struct, IPixel<TPixel>
         {
             ReadOnlySpan<byte> newScanline = ToArrayByBitsLength(defilteredScanline, this.bytesPerScanline, this.header.BitDepth);
-            Span<byte> pal = this.palette;
+            ReadOnlySpan<Rgb24> pal = MemoryMarshal.Cast<byte, Rgb24>(this.palette);
             var color = default(TPixel);
 
             var rgba = default(Rgba32);
@@ -865,10 +865,9 @@ namespace SixLabors.ImageSharp.Formats.Png
                 for (int x = 0; x < this.header.Width; x++)
                 {
                     int index = newScanline[x];
-                    int pixelOffset = index * 3;
 
                     rgba.A = this.paletteAlpha.Length > index ? this.paletteAlpha[index] : (byte)255;
-                    rgba.Rgb = pal.Slice(pixelOffset).AsRgb24();
+                    rgba.Rgb = pal[index];
 
                     color.PackFromRgba32(rgba);
                     row[x] = color;
@@ -881,9 +880,8 @@ namespace SixLabors.ImageSharp.Formats.Png
                 for (int x = 0; x < this.header.Width; x++)
                 {
                     int index = newScanline[x];
-                    int pixelOffset = index * 3;
 
-                    rgba.Rgb = pal.Slice(pixelOffset).AsRgb24();
+                    rgba.Rgb = pal[index];
 
                     color.PackFromRgba32(rgba);
                     row[x] = color;
@@ -946,7 +944,7 @@ namespace SixLabors.ImageSharp.Formats.Png
 
                     ReadOnlySpan<byte> newScanline = ToArrayByBitsLength(scanlineBuffer, this.bytesPerScanline, this.header.BitDepth);
                     var rgba = default(Rgba32);
-                    Span<byte> pal = this.palette;
+                    Span<Rgb24> pal = MemoryMarshal.Cast<byte, Rgb24>(this.palette);
 
                     if (this.paletteAlpha != null && this.paletteAlpha.Length > 0)
                     {
@@ -956,10 +954,9 @@ namespace SixLabors.ImageSharp.Formats.Png
                         for (int x = pixelOffset, o = 0; x < this.header.Width; x += increment, o++)
                         {
                             int index = newScanline[o];
-                            int offset = index * 3;
 
                             rgba.A = this.paletteAlpha.Length > index ? this.paletteAlpha[index] : (byte)255;
-                            rgba.Rgb = pal.Slice(offset).AsRgb24();
+                            rgba.Rgb = pal[index];
 
                             color.PackFromRgba32(rgba);
                             rowSpan[x] = color;
@@ -972,10 +969,8 @@ namespace SixLabors.ImageSharp.Formats.Png
                         for (int x = pixelOffset, o = 0; x < this.header.Width; x += increment, o++)
                         {
                             int index = newScanline[o];
-                            int offset = index * 3;
-
-                            rgba.Rgb = pal.Slice(offset).AsRgb24();
 
+                            rgba.Rgb = pal[index];
                             color.PackFromRgba32(rgba);
                             rowSpan[x] = color;
                         }

From ddda1005e9cb50bee32b8a72d06eb6cbef370c0e Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Wed, 9 May 2018 16:44:27 -0700
Subject: [PATCH 05/21] Simplify GifDecoder

---
 src/ImageSharp/Formats/Gif/GifDecoderCore.cs | 24 +++++++-------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/src/ImageSharp/Formats/Gif/GifDecoderCore.cs b/src/ImageSharp/Formats/Gif/GifDecoderCore.cs
index 6c03bd2b1..4fbd4baf5 100644
--- a/src/ImageSharp/Formats/Gif/GifDecoderCore.cs
+++ b/src/ImageSharp/Formats/Gif/GifDecoderCore.cs
@@ -39,11 +39,6 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// </summary>
         private IManagedByteBuffer globalColorTable;
 
-        /// <summary>
-        /// The global color table length
-        /// </summary>
-        private int globalColorTableLength;
-
         /// <summary>
         /// The area to restore.
         /// </summary>
@@ -333,8 +328,8 @@ namespace SixLabors.ImageSharp.Formats.Gif
                 indices = this.configuration.MemoryManager.AllocateManagedByteBuffer(imageDescriptor.Width * imageDescriptor.Height, true);
 
                 this.ReadFrameIndices(imageDescriptor, indices.Span);
-                IManagedByteBuffer colorTable = localColorTable ?? this.globalColorTable;
-                this.ReadFrameColors(ref image, ref previousFrame, indices.Span, colorTable.Span, imageDescriptor);
+                ReadOnlySpan<Rgb24> colorTable = MemoryMarshal.Cast<byte, Rgb24>((localColorTable ?? this.globalColorTable).Span);
+                this.ReadFrameColors(ref image, ref previousFrame, indices.Span, colorTable, imageDescriptor);
 
                 // Skip any remaining blocks
                 this.Skip(0);
@@ -370,7 +365,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <param name="indices">The indexed pixels.</param>
         /// <param name="colorTable">The color table containing the available colors.</param>
         /// <param name="descriptor">The <see cref="GifImageDescriptor"/></param>
-        private void ReadFrameColors<TPixel>(ref Image<TPixel> image, ref ImageFrame<TPixel> previousFrame, Span<byte> indices, Span<byte> colorTable, in GifImageDescriptor descriptor)
+        private void ReadFrameColors<TPixel>(ref Image<TPixel> image, ref ImageFrame<TPixel> previousFrame, Span<byte> indices, ReadOnlySpan<Rgb24> colorTable, in GifImageDescriptor descriptor)
             where TPixel : struct, IPixel<TPixel>
         {
             ref byte indicesRef = ref MemoryMarshal.GetReference(indices);
@@ -458,11 +453,8 @@ namespace SixLabors.ImageSharp.Formats.Gif
                     if (this.graphicsControlExtension.TransparencyFlag == false ||
                         this.graphicsControlExtension.TransparencyIndex != index)
                     {
-                        int indexOffset = index * 3;
-
                         ref TPixel pixel = ref Unsafe.Add(ref rowRef, x);
-                        rgba.Rgb = colorTable.Slice(indexOffset).AsRgb24();
-
+                        rgba.Rgb = colorTable[index];
                         pixel.PackFromRgba32(rgba);
                     }
 
@@ -534,12 +526,12 @@ namespace SixLabors.ImageSharp.Formats.Gif
 
             if (this.logicalScreenDescriptor.GlobalColorTableFlag)
             {
-                this.globalColorTableLength = this.logicalScreenDescriptor.GlobalColorTableSize * 3;
+                int globalColorTableLength = this.logicalScreenDescriptor.GlobalColorTableSize * 3;
 
-                this.globalColorTable = this.MemoryManager.AllocateManagedByteBuffer(this.globalColorTableLength, true);
+                this.globalColorTable = this.MemoryManager.AllocateManagedByteBuffer(globalColorTableLength, true);
 
-                // Read the global color table from the stream
-                stream.Read(this.globalColorTable.Array, 0, this.globalColorTableLength);
+                // Read the global color table data from the stream
+                stream.Read(this.globalColorTable.Array, 0, globalColorTableLength);
             }
         }
     }

From b6ad0930c58d3eb075b82ea6a0857a7f87fcc836 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Wed, 9 May 2018 16:44:34 -0700
Subject: [PATCH 06/21] Remove ByteExtensions

---
 .../Common/Extensions/ByteExtensions.cs       | 26 -------------------
 1 file changed, 26 deletions(-)
 delete mode 100644 src/ImageSharp/Common/Extensions/ByteExtensions.cs

diff --git a/src/ImageSharp/Common/Extensions/ByteExtensions.cs b/src/ImageSharp/Common/Extensions/ByteExtensions.cs
deleted file mode 100644
index ee41096cf..000000000
--- a/src/ImageSharp/Common/Extensions/ByteExtensions.cs
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright (c) Six Labors and contributors.
-// Licensed under the Apache License, Version 2.0.
-
-using System;
-using System.Runtime.CompilerServices;
-using SixLabors.ImageSharp.PixelFormats;
-
-namespace SixLabors.ImageSharp
-{
-    /// <summary>
-    /// Extension methods for the <see cref="byte"/> struct buffers.
-    /// </summary>
-    internal static class ByteExtensions
-    {
-        /// <summary>
-        /// Returns a reference to the given position of the span unsafe casted to <see cref="ImageSharp.PixelFormats.Rgb24"/>.
-        /// </summary>
-        /// <param name="bytes">The byte span.</param>
-        /// <returns>The <see cref="ImageSharp.PixelFormats.Rgb24"/> reference at the given offset.</returns>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static ref Rgb24 AsRgb24(this Span<byte> bytes)
-        {
-            return ref Unsafe.As<byte, Rgb24>(ref bytes[0]);
-        }
-    }
-}
\ No newline at end of file

From 2e5110fdf23aa23420a43fc7ff1bfee057ec5d8b Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Wed, 9 May 2018 16:44:45 -0700
Subject: [PATCH 07/21] Simplfiy ToRgbaHex

---
 src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs b/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs
index 184928d0e..f5ebdb3fd 100644
--- a/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs
+++ b/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs
@@ -76,7 +76,10 @@ namespace SixLabors.ImageSharp.PixelFormats
         /// </returns>
         private static string ToRgbaHex(string hex)
         {
-            hex = hex.StartsWith("#") ? hex.Substring(1) : hex;
+            if (hex[0] == '#')
+            {
+                hex = hex.Substring(1);
+            }
 
             if (hex.Length == 8)
             {

From c8ca5d16a6c541ca05a26b42e645f9c92656a801 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Wed, 9 May 2018 16:56:08 -0700
Subject: [PATCH 08/21] =?UTF-8?q?=F0=9F=91=AE?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/ImageSharp/Formats/Png/PngDecoderCore.cs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/ImageSharp/Formats/Png/PngDecoderCore.cs b/src/ImageSharp/Formats/Png/PngDecoderCore.cs
index b89c655c8..cc98b8450 100644
--- a/src/ImageSharp/Formats/Png/PngDecoderCore.cs
+++ b/src/ImageSharp/Formats/Png/PngDecoderCore.cs
@@ -948,7 +948,6 @@ namespace SixLabors.ImageSharp.Formats.Png
 
                     if (this.paletteAlpha != null && this.paletteAlpha.Length > 0)
                     {
-
                         // If the alpha palette is not null and has one or more entries, this means, that the image contains an alpha
                         // channel and we should try to read it.
                         for (int x = pixelOffset, o = 0; x < this.header.Width; x += increment, o++)

From 82ac8a720abac930e0985119bcf30ea7fa361d60 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Thu, 10 May 2018 07:59:51 -0700
Subject: [PATCH 09/21] Rename Gaurd.NotNullOrEmpty to NotNullOrWhiteSpace to
 match behavior & cleanup messages.

Also remove the unused message arguments.
---
 src/ImageSharp/Common/Helpers/Guard.cs        | 67 ++++++++-----------
 src/ImageSharp/MetaData/ImageProperty.cs      |  2 +-
 .../PixelFormats/ColorBuilder{TPixel}.cs      |  2 +-
 3 files changed, 31 insertions(+), 40 deletions(-)

diff --git a/src/ImageSharp/Common/Helpers/Guard.cs b/src/ImageSharp/Common/Helpers/Guard.cs
index 9f0a46f80..603cf566f 100644
--- a/src/ImageSharp/Common/Helpers/Guard.cs
+++ b/src/ImageSharp/Common/Helpers/Guard.cs
@@ -15,16 +15,15 @@ namespace SixLabors.ImageSharp
     internal static class Guard
     {
         /// <summary>
-        /// Verifies, that the method parameter with specified object value is not null
-        /// and throws an exception if it is found to be so.
+        /// Ensures that the value is not null.
         /// </summary>
-        /// <param name="target">The target object, which cannot be null.</param>
+        /// <param name="value">The target object, which cannot be null.</param>
         /// <param name="parameterName">The name of the parameter that is to be checked.</param>
         /// <param name="message">The error message, if any to add to the exception.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="target"/> is null</exception>
-        public static void NotNull(object target, string parameterName, string message = "")
+        /// <exception cref="ArgumentNullException"><paramref name="value"/> is null</exception>
+        public static void NotNull(object value, string parameterName, string message = "")
         {
-            if (target == null)
+            if (value == null)
             {
                 if (!string.IsNullOrWhiteSpace(message))
                 {
@@ -36,57 +35,49 @@ namespace SixLabors.ImageSharp
         }
 
         /// <summary>
-        /// Verifies, that the string method parameter with specified object value and message
-        /// is not null, not empty and does not contain only blanks and throws an exception
-        /// if the object is null.
+        /// Ensures that the target value is not null, empty, or whitespace.
         /// </summary>
-        /// <param name="target">The target string, which should be checked against being null or empty.</param>
+        /// <param name="value">The target string, which should be checked against being null or empty.</param>
         /// <param name="parameterName">Name of the parameter.</param>
-        /// <param name="message">The error message, if any to add to the exception.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="target"/> is null.</exception>
-        /// <exception cref="ArgumentException"><paramref name="target"/> is empty or contains only blanks.</exception>
-        public static void NotNullOrEmpty(string target, string parameterName, string message = "")
+        /// <exception cref="ArgumentNullException"><paramref name="value"/> is null.</exception>
+        /// <exception cref="ArgumentException"><paramref name="value"/> is empty or contains only blanks.</exception>
+        public static void NotNullOrWhiteSpace(string value, string parameterName)
         {
-            NotNull(target, parameterName, message);
-
-            if (string.IsNullOrWhiteSpace(target))
+            if (value == null)
             {
-                if (!string.IsNullOrWhiteSpace(message))
-                {
-                    throw new ArgumentException(message, parameterName);
-                }
+                throw new ArgumentNullException(parameterName);
+            }
 
-                throw new ArgumentException("Value cannot be null or empty and cannot contain only blanks.", parameterName);
+            if (string.IsNullOrWhiteSpace(value))
+            {
+                throw new ArgumentException("Must not be empty or whitespace.", parameterName);
             }
         }
 
         /// <summary>
-        /// Verifies, that the enumeration is not null and not empty.
+        /// Ensures that the enumeration is not null or empty.
         /// </summary>
-        /// <typeparam name="T">The type of objects in the <paramref name="target"/></typeparam>
-        /// <param name="target">The target enumeration, which should be checked against being null or empty.</param>
+        /// <typeparam name="T">The type of objects in the <paramref name="value"/></typeparam>
+        /// <param name="value">The target enumeration, which should be checked against being null or empty.</param>
         /// <param name="parameterName">Name of the parameter.</param>
         /// <param name="message">The error message, if any to add to the exception.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="target"/> is null.</exception>
-        /// <exception cref="ArgumentException"><paramref name="target"/> is empty.</exception>
-        public static void NotNullOrEmpty<T>(IEnumerable<T> target, string parameterName, string message = "")
+        /// <exception cref="ArgumentNullException"><paramref name="value"/> is null.</exception>
+        /// <exception cref="ArgumentException"><paramref name="value"/> is empty.</exception>
+        public static void NotNullOrEmpty<T>(IEnumerable<T> value, string parameterName)
         {
-            NotNull(target, parameterName, message);
-
-            if (!target.Any())
+            if (value == null)
             {
-                if (!string.IsNullOrWhiteSpace(message))
-                {
-                    throw new ArgumentException(message, parameterName);
-                }
+                throw new ArgumentNullException(parameterName);
+            }
 
-                throw new ArgumentException("Value cannot be empty.", parameterName);
+            if (!value.Any())
+            {
+                throw new ArgumentException("Must not be empty.", parameterName);
             }
         }
 
         /// <summary>
-        /// Verifies that the specified value is less than a maximum value
-        /// and throws an exception if it is not.
+        /// Ensures that the specified value is less than a maximum value.
         /// </summary>
         /// <param name="value">The target value, which should be validated.</param>
         /// <param name="max">The maximum value.</param>
diff --git a/src/ImageSharp/MetaData/ImageProperty.cs b/src/ImageSharp/MetaData/ImageProperty.cs
index c67c1f3cf..3e0cccd42 100644
--- a/src/ImageSharp/MetaData/ImageProperty.cs
+++ b/src/ImageSharp/MetaData/ImageProperty.cs
@@ -19,7 +19,7 @@ namespace SixLabors.ImageSharp.MetaData
         /// <param name="value">The value of the property.</param>
         public ImageProperty(string name, string value)
         {
-            Guard.NotNullOrEmpty(name, nameof(name));
+            Guard.NotNullOrWhiteSpace(name, nameof(name));
 
             this.Name = name;
             this.Value = value;
diff --git a/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs b/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs
index f5ebdb3fd..1e7645aeb 100644
--- a/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs
+++ b/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs
@@ -23,7 +23,7 @@ namespace SixLabors.ImageSharp.PixelFormats
         /// <returns>Returns a <typeparamref name="TPixel"/> that represents the color defined by the provided RGBA heax string.</returns>
         public static TPixel FromHex(string hex)
         {
-            Guard.NotNullOrEmpty(hex, nameof(hex));
+            Guard.NotNullOrWhiteSpace(hex, nameof(hex));
 
             hex = ToRgbaHex(hex);
             uint packedValue;

From f47c4bcbcffbfc4de612ccd9640ca7b38e6e8d98 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Thu, 10 May 2018 08:09:10 -0700
Subject: [PATCH 10/21] Don't use Linq to check if IEnumerable is empty.

---
 src/ImageSharp/ImageFrameCollection.cs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/ImageSharp/ImageFrameCollection.cs b/src/ImageSharp/ImageFrameCollection.cs
index 0318a7068..cacad34a4 100644
--- a/src/ImageSharp/ImageFrameCollection.cs
+++ b/src/ImageSharp/ImageFrameCollection.cs
@@ -32,7 +32,7 @@ namespace SixLabors.ImageSharp
         internal ImageFrameCollection(Image<TPixel> parent, IEnumerable<ImageFrame<TPixel>> frames)
         {
             Guard.NotNull(parent, nameof(parent));
-            Guard.NotNullOrEmpty(frames, nameof(frames));
+            Guard.NotNull(frames, nameof(frames));
 
             this.parent = parent;
 
@@ -42,6 +42,12 @@ namespace SixLabors.ImageSharp
                 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>

From 54c26c476aa16b57ffb8a13a0d99f04a39cd7925 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Thu, 10 May 2018 08:12:32 -0700
Subject: [PATCH 11/21] React to Gaurd changes

---
 src/ImageSharp/Common/Helpers/Guard.cs       | 26 +++++---------------
 src/ImageSharp/ImageExtensions.cs            |  2 +-
 tests/ImageSharp.Tests/Helpers/GuardTests.cs | 12 ++++-----
 3 files changed, 13 insertions(+), 27 deletions(-)

diff --git a/src/ImageSharp/Common/Helpers/Guard.cs b/src/ImageSharp/Common/Helpers/Guard.cs
index 603cf566f..9258beb36 100644
--- a/src/ImageSharp/Common/Helpers/Guard.cs
+++ b/src/ImageSharp/Common/Helpers/Guard.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 
 namespace SixLabors.ImageSharp
 {
@@ -19,17 +18,11 @@ namespace SixLabors.ImageSharp
         /// </summary>
         /// <param name="value">The target object, which cannot be null.</param>
         /// <param name="parameterName">The name of the parameter that is to be checked.</param>
-        /// <param name="message">The error message, if any to add to the exception.</param>
         /// <exception cref="ArgumentNullException"><paramref name="value"/> is null</exception>
-        public static void NotNull(object value, string parameterName, string message = "")
+        public static void NotNull(object value, string parameterName)
         {
             if (value == null)
             {
-                if (!string.IsNullOrWhiteSpace(message))
-                {
-                    throw new ArgumentNullException(parameterName, message);
-                }
-
                 throw new ArgumentNullException(parameterName);
             }
         }
@@ -60,17 +53,16 @@ namespace SixLabors.ImageSharp
         /// <typeparam name="T">The type of objects in the <paramref name="value"/></typeparam>
         /// <param name="value">The target enumeration, which should be checked against being null or empty.</param>
         /// <param name="parameterName">Name of the parameter.</param>
-        /// <param name="message">The error message, if any to add to the exception.</param>
         /// <exception cref="ArgumentNullException"><paramref name="value"/> is null.</exception>
         /// <exception cref="ArgumentException"><paramref name="value"/> is empty.</exception>
-        public static void NotNullOrEmpty<T>(IEnumerable<T> value, string parameterName)
+        public static void NotNullOrEmpty<T>(ICollection<T> value, string parameterName)
         {
             if (value == null)
             {
                 throw new ArgumentNullException(parameterName);
             }
 
-            if (!value.Any())
+            if (value.Count == 0)
             {
                 throw new ArgumentException("Must not be empty.", parameterName);
             }
@@ -182,15 +174,9 @@ namespace SixLabors.ImageSharp
         /// Verifies, that the method parameter with specified target value is true
         /// and throws an exception if it is found to be so.
         /// </summary>
-        /// <param name="target">
-        /// The target value, which cannot be false.
-        /// </param>
-        /// <param name="parameterName">
-        /// The name of the parameter that is to be checked.
-        /// </param>
-        /// <param name="message">
-        /// The error message, if any to add to the exception.
-        /// </param>
+        /// <param name="target">The target value, which cannot be false.</param>
+        /// <param name="parameterName">The name of the parameter that is to be checked.</param>
+        /// <param name="message">The error message, if any to add to the exception.</param>
         /// <exception cref="ArgumentException">
         /// <paramref name="target"/> is false
         /// </exception>
diff --git a/src/ImageSharp/ImageExtensions.cs b/src/ImageSharp/ImageExtensions.cs
index 2cdb71fc0..75d947469 100644
--- a/src/ImageSharp/ImageExtensions.cs
+++ b/src/ImageSharp/ImageExtensions.cs
@@ -30,7 +30,7 @@ namespace SixLabors.ImageSharp
         public static void Save<TPixel>(this Image<TPixel> source, string filePath)
             where TPixel : struct, IPixel<TPixel>
         {
-            Guard.NotNullOrEmpty(filePath, nameof(filePath));
+            Guard.NotNullOrWhiteSpace(filePath, nameof(filePath));
 
             string ext = Path.GetExtension(filePath).Trim('.');
             IImageFormat format = source.GetConfiguration().ImageFormatsManager.FindFormatByFileExtension(ext);
diff --git a/tests/ImageSharp.Tests/Helpers/GuardTests.cs b/tests/ImageSharp.Tests/Helpers/GuardTests.cs
index 83075dc83..42913e02d 100644
--- a/tests/ImageSharp.Tests/Helpers/GuardTests.cs
+++ b/tests/ImageSharp.Tests/Helpers/GuardTests.cs
@@ -35,27 +35,27 @@ namespace SixLabors.ImageSharp.Tests.Helpers
         /// </summary>
         [Fact]
         [SuppressMessage("StyleCop.CSharp.ReadabilityRules", "SA1122:UseStringEmptyForEmptyStrings", Justification = "Reviewed. Suppression is OK here.")]
-        public void NotEmptyThrowsWhenEmpty()
+        public void NotEmptyOrWhiteSpaceThrowsWhenEmpty()
         {
-            Assert.Throws<ArgumentException>(() => Guard.NotNullOrEmpty("", string.Empty));
+            Assert.Throws<ArgumentException>(() => Guard.NotNullOrWhiteSpace("", string.Empty));
         }
 
         /// <summary>
         /// Tests that the <see cref="M:Guard.NotEmpty"/> method throws when the argument is whitespace.
         /// </summary>
         [Fact]
-        public void NotEmptyThrowsWhenWhitespace()
+        public void NotEmptyOrWhiteSpaceThrowsOnWhitespace()
         {
-            Assert.Throws<ArgumentException>(() => Guard.NotNullOrEmpty(" ", string.Empty));
+            Assert.Throws<ArgumentException>(() => Guard.NotNullOrWhiteSpace(" ", string.Empty));
         }
 
         /// <summary>
         /// Tests that the <see cref="M:Guard.NotEmpty"/> method throws when the argument name is null.
         /// </summary>
         [Fact]
-        public void NotEmptyThrowsWhenParameterNameNull()
+        public void NotEmptyOrWhiteSpaceThrowsWhenParameterNameNull()
         {
-            Assert.Throws<ArgumentNullException>(() => Guard.NotNullOrEmpty(null, null));
+            Assert.Throws<ArgumentNullException>(() => Guard.NotNullOrWhiteSpace(null, null));
         }
 
         /// <summary>

From 6a3688d0981eb75b956d1c11fe61a2c14b2dcf88 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Thu, 10 May 2018 08:12:59 -0700
Subject: [PATCH 12/21] Verify ColorBuilder throws on null and empty

---
 .../PixelFormats/ColorBuilderTests.cs         | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 tests/ImageSharp.Tests/PixelFormats/ColorBuilderTests.cs

diff --git a/tests/ImageSharp.Tests/PixelFormats/ColorBuilderTests.cs b/tests/ImageSharp.Tests/PixelFormats/ColorBuilderTests.cs
new file mode 100644
index 000000000..6c139c2c0
--- /dev/null
+++ b/tests/ImageSharp.Tests/PixelFormats/ColorBuilderTests.cs
@@ -0,0 +1,31 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using SixLabors.ImageSharp.PixelFormats;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Tests.Colors
+{
+    public class ColorBuilderTests
+    {
+        [Fact]
+        public void ParseHexLeadingPoundIsOptional()
+        {
+            Assert.Equal(new Rgb24(0, 128, 128), ColorBuilder<Rgb24>.FromHex("#008080"));
+            Assert.Equal(new Rgb24(0, 128, 128), ColorBuilder<Rgb24>.FromHex("008080"));
+        }
+
+        [Fact]
+        public void ParseHexThrowsOnEmpty()
+        {
+            Assert.Throws<ArgumentException>(() => ColorBuilder<Rgb24>.FromHex(""));
+        }
+
+        [Fact]
+        public void ParseHexThrowsOnNull()
+        {
+            Assert.Throws<ArgumentNullException>(() => ColorBuilder<Rgb24>.FromHex(null));
+        }
+    }
+}

From a14ca40dfbf7397a770221459d37906f4c563595 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Thu, 10 May 2018 08:21:33 -0700
Subject: [PATCH 13/21] Optimize ColorBuilder

---
 .../PixelFormats/ColorBuilder{TPixel}.cs      | 21 ++++++++-----------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs b/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs
index 1e7645aeb..c2c0277f9 100644
--- a/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs
+++ b/src/ImageSharp/PixelFormats/ColorBuilder{TPixel}.cs
@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
+using System.Buffers.Binary;
 using System.Globalization;
 
 namespace SixLabors.ImageSharp.PixelFormats
@@ -26,18 +27,14 @@ namespace SixLabors.ImageSharp.PixelFormats
             Guard.NotNullOrWhiteSpace(hex, nameof(hex));
 
             hex = ToRgbaHex(hex);
-            uint packedValue;
-            if (hex == null || !uint.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out packedValue))
+
+            if (hex == null || !uint.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out uint packedValue))
             {
                 throw new ArgumentException("Hexadecimal string is not in the correct format.", nameof(hex));
             }
 
             TPixel result = default;
-            var rgba = new Rgba32(
-                (byte)(packedValue >> 24),
-                (byte)(packedValue >> 16),
-                (byte)(packedValue >> 8),
-                (byte)(packedValue >> 0));
+            var rgba = new Rgba32(BinaryPrimitives.ReverseEndianness(packedValue));
 
             result.PackFromRgba32(rgba);
             return result;
@@ -96,12 +93,12 @@ namespace SixLabors.ImageSharp.PixelFormats
                 return null;
             }
 
-            string red = char.ToString(hex[0]);
-            string green = char.ToString(hex[1]);
-            string blue = char.ToString(hex[2]);
-            string alpha = hex.Length == 3 ? "F" : char.ToString(hex[3]);
+            char r = hex[0];
+            char g = hex[1];
+            char b = hex[2];
+            char a = hex.Length == 3 ? 'F' : hex[3];
 
-            return string.Concat(red, red, green, green, blue, blue, alpha, alpha);
+            return new string(new[] { r, r, g, g, b, b, a, a });
         }
     }
 }
\ No newline at end of file

From 5d02aebdc8c0c16d625ff0690ad058ebfb66a7a5 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Thu, 10 May 2018 08:24:56 -0700
Subject: [PATCH 14/21] Improve ColorBuilder test coverage

---
 tests/ImageSharp.Tests/PixelFormats/ColorBuilderTests.cs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tests/ImageSharp.Tests/PixelFormats/ColorBuilderTests.cs b/tests/ImageSharp.Tests/PixelFormats/ColorBuilderTests.cs
index 6c139c2c0..e56cac279 100644
--- a/tests/ImageSharp.Tests/PixelFormats/ColorBuilderTests.cs
+++ b/tests/ImageSharp.Tests/PixelFormats/ColorBuilderTests.cs
@@ -3,12 +3,21 @@
 
 using System;
 using SixLabors.ImageSharp.PixelFormats;
+
 using Xunit;
 
 namespace SixLabors.ImageSharp.Tests.Colors
 {
     public class ColorBuilderTests
     {
+        [Fact]
+        public void ParseShortHex()
+        {
+            Assert.Equal(new Rgb24(255, 255, 255), ColorBuilder<Rgb24>.FromHex("#fff"));
+            Assert.Equal(new Rgb24(255, 255, 255), ColorBuilder<Rgb24>.FromHex("fff"));
+            Assert.Equal(new Rgba32(0, 0, 0, 255), ColorBuilder<Rgba32>.FromHex("000f"));
+        }
+
         [Fact]
         public void ParseHexLeadingPoundIsOptional()
         {

From 00a0451e211343730f74de83fb8efbfbef7810ec Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Thu, 10 May 2018 09:08:00 -0700
Subject: [PATCH 15/21] Allow leading period in FindFormatByFileExtension

---
 src/ImageSharp/Formats/ImageFormatManager.cs               | 7 +++++++
 src/ImageSharp/ImageExtensions.cs                          | 2 +-
 .../TestUtilities/TestEnvironment.Formats.cs               | 4 ++--
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/ImageSharp/Formats/ImageFormatManager.cs b/src/ImageSharp/Formats/ImageFormatManager.cs
index 67ba11147..4e33a0445 100644
--- a/src/ImageSharp/Formats/ImageFormatManager.cs
+++ b/src/ImageSharp/Formats/ImageFormatManager.cs
@@ -85,6 +85,13 @@ namespace SixLabors.ImageSharp.Formats
         /// <returns>The <see cref="IImageFormat"/> if found otherwise null</returns>
         public IImageFormat FindFormatByFileExtension(string extension)
         {
+            Guard.NotNullOrWhiteSpace(extension, nameof(extension));
+
+            if (extension[0] == '.')
+            {
+                extension = extension.Substring(1);
+            }
+
             return this.imageFormats.FirstOrDefault(x => x.FileExtensions.Contains(extension, StringComparer.OrdinalIgnoreCase));
         }
 
diff --git a/src/ImageSharp/ImageExtensions.cs b/src/ImageSharp/ImageExtensions.cs
index 75d947469..9f9a7e57a 100644
--- a/src/ImageSharp/ImageExtensions.cs
+++ b/src/ImageSharp/ImageExtensions.cs
@@ -32,7 +32,7 @@ namespace SixLabors.ImageSharp
         {
             Guard.NotNullOrWhiteSpace(filePath, nameof(filePath));
 
-            string ext = Path.GetExtension(filePath).Trim('.');
+            string ext = Path.GetExtension(filePath);
             IImageFormat format = source.GetConfiguration().ImageFormatsManager.FindFormatByFileExtension(ext);
             if (format == null)
             {
diff --git a/tests/ImageSharp.Tests/TestUtilities/TestEnvironment.Formats.cs b/tests/ImageSharp.Tests/TestUtilities/TestEnvironment.Formats.cs
index fa9497a8f..6bebf3887 100644
--- a/tests/ImageSharp.Tests/TestUtilities/TestEnvironment.Formats.cs
+++ b/tests/ImageSharp.Tests/TestUtilities/TestEnvironment.Formats.cs
@@ -32,8 +32,8 @@ namespace SixLabors.ImageSharp.Tests
 
         internal static IImageFormat GetImageFormat(string filePath)
         {
-            string extension = Path.GetExtension(filePath).ToLower();
-            if (extension[0] == '.') extension = extension.Substring(1);
+            string extension = Path.GetExtension(filePath);
+            
             IImageFormat format = Configuration.ImageFormatsManager.FindFormatByFileExtension(extension);
             return format;
         }

From b220a1b46764b800d57ec46bf6d4aa71fe98cb83 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Thu, 10 May 2018 13:47:50 -0700
Subject: [PATCH 16/21] Use ReadOnlySpans in LoadPixelData

---
 src/ImageSharp/Image.LoadPixelData.cs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/ImageSharp/Image.LoadPixelData.cs b/src/ImageSharp/Image.LoadPixelData.cs
index 5f85d61ba..307660b5a 100644
--- a/src/ImageSharp/Image.LoadPixelData.cs
+++ b/src/ImageSharp/Image.LoadPixelData.cs
@@ -33,7 +33,7 @@ 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 Image<TPixel> LoadPixelData<TPixel>(Span<TPixel> data, int width, int height)
+        public static Image<TPixel> LoadPixelData<TPixel>(ReadOnlySpan<TPixel> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
             => LoadPixelData(Configuration.Default, data, width, height);
 
@@ -72,7 +72,7 @@ namespace SixLabors.ImageSharp
         /// <returns>A new <see cref="Image{TPixel}"/>.</returns>
         public static Image<TPixel> LoadPixelData<TPixel>(Configuration config, byte[] data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
-            => LoadPixelData(config, MemoryMarshal.Cast<byte, TPixel>(data.AsSpan()), width, height);
+            => LoadPixelData(config, MemoryMarshal.Cast<byte, TPixel>(new ReadOnlySpan<byte>(data)), width, height);
 
         /// <summary>
         /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given byte array in <typeparamref name="TPixel"/> format.
@@ -83,7 +83,7 @@ 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 Image<TPixel> LoadPixelData<TPixel>(Configuration config, Span<byte> data, int width, int height)
+        public static Image<TPixel> LoadPixelData<TPixel>(Configuration config, ReadOnlySpan<byte> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
             => LoadPixelData(config, MemoryMarshal.Cast<byte, TPixel>(data), width, height);
 
@@ -99,7 +99,7 @@ namespace SixLabors.ImageSharp
         public static Image<TPixel> LoadPixelData<TPixel>(Configuration config, TPixel[] data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
         {
-            return LoadPixelData(config, data.AsSpan(), width, height);
+            return LoadPixelData(config, new ReadOnlySpan<TPixel>(data), width, height);
         }
 
         /// <summary>
@@ -111,7 +111,7 @@ 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 Image<TPixel> LoadPixelData<TPixel>(Configuration config, Span<TPixel> data, int width, int height)
+        public static Image<TPixel> LoadPixelData<TPixel>(Configuration config, ReadOnlySpan<TPixel> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
         {
             int count = width * height;

From 86d68315af8ef540de9b0c9454c17488c7599db8 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Thu, 10 May 2018 13:48:16 -0700
Subject: [PATCH 17/21] Allow pixel data to be saved directly to a span

---
 src/ImageSharp/ImageExtensions.cs | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/src/ImageSharp/ImageExtensions.cs b/src/ImageSharp/ImageExtensions.cs
index 9f9a7e57a..192287ba5 100644
--- a/src/ImageSharp/ImageExtensions.cs
+++ b/src/ImageSharp/ImageExtensions.cs
@@ -4,13 +4,11 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
 using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.PixelFormats;
-using SixLabors.Primitives;
 
 namespace SixLabors.ImageSharp
 {
@@ -198,24 +196,24 @@ namespace SixLabors.ImageSharp
         }
 
         /// <summary>
-        /// Saves the raw image to the given bytes.
+        /// Saves the raw image to the given byte buffer.
         /// </summary>
         /// <typeparam name="TPixel">The Pixel format.</typeparam>
         /// <param name="source">The source image</param>
         /// <param name="buffer">The buffer to save the raw pixel data to.</param>
         /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
-        internal static void SavePixelData<TPixel>(this Image<TPixel> source, Span<byte> buffer)
+        public static void SavePixelData<TPixel>(this Image<TPixel> source, Span<byte> buffer)
             where TPixel : struct, IPixel<TPixel>
             => source.Frames.RootFrame.SavePixelData(MemoryMarshal.Cast<byte, TPixel>(buffer));
 
         /// <summary>
-        /// Saves the raw image to the given bytes.
+        /// Saves the raw image to the given byte buffer.
         /// </summary>
         /// <typeparam name="TPixel">The Pixel format.</typeparam>
         /// <param name="source">The source image</param>
         /// <param name="buffer">The buffer to save the raw pixel data to.</param>
         /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
-        internal static void SavePixelData<TPixel>(this ImageFrame<TPixel> source, Span<TPixel> buffer)
+        public static void SavePixelData<TPixel>(this ImageFrame<TPixel> source, Span<TPixel> buffer)
             where TPixel : struct, IPixel<TPixel>
         {
             Span<TPixel> sourceBuffer = source.GetPixelSpan();
@@ -224,4 +222,4 @@ namespace SixLabors.ImageSharp
             sourceBuffer.CopyTo(buffer);
         }
     }
-}
+}
\ No newline at end of file

From 14d77efc5c41d1305471598103b9c1eb499ac617 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Fri, 11 May 2018 10:31:17 -0700
Subject: [PATCH 18/21] Update Span ->ReadOnlySpan

---
 src/ImageSharp/Image.LoadPixelData.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ImageSharp/Image.LoadPixelData.cs b/src/ImageSharp/Image.LoadPixelData.cs
index 307660b5a..282f98086 100644
--- a/src/ImageSharp/Image.LoadPixelData.cs
+++ b/src/ImageSharp/Image.LoadPixelData.cs
@@ -57,7 +57,7 @@ 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 Image<TPixel> LoadPixelData<TPixel>(Span<byte> data, int width, int height)
+        public static Image<TPixel> LoadPixelData<TPixel>(ReadOnlySpan<byte> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
             => LoadPixelData<TPixel>(Configuration.Default, data, width, height);
 

From c161a7ee0b8b91e85701fcdfbefa51e1f2c30b67 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Fri, 11 May 2018 10:31:47 -0700
Subject: [PATCH 19/21] Tidy up ImageExtension docs

---
 src/ImageSharp/ImageExtensions.cs | 78 +++++++++++++++----------------
 1 file changed, 39 insertions(+), 39 deletions(-)

diff --git a/src/ImageSharp/ImageExtensions.cs b/src/ImageSharp/ImageExtensions.cs
index 192287ba5..d8cda2f8f 100644
--- a/src/ImageSharp/ImageExtensions.cs
+++ b/src/ImageSharp/ImageExtensions.cs
@@ -19,10 +19,10 @@ namespace SixLabors.ImageSharp
     {
 #if !NETSTANDARD1_1
         /// <summary>
-        /// Saves the image to the given stream using the currently loaded image format.
+        /// Writes the image to the given stream using the currently loaded image format.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
-        /// <param name="source">The source image</param>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
+        /// <param name="source">The source image.</param>
         /// <param name="filePath">The file path to save the image to.</param>
         /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
         public static void Save<TPixel>(this Image<TPixel> source, string filePath)
@@ -62,13 +62,13 @@ namespace SixLabors.ImageSharp
         }
 
         /// <summary>
-        /// Saves the image to the given stream using the currently loaded image format.
+        /// Writes the image to the given stream using the currently loaded image format.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
-        /// <param name="source">The source image</param>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
+        /// <param name="source">The source image.</param>
         /// <param name="filePath">The file path to save the image to.</param>
         /// <param name="encoder">The encoder to save the image with.</param>
-        /// <exception cref="System.ArgumentNullException">Thrown if the encoder is null.</exception>
+        /// <exception cref="ArgumentNullException">Thrown if the encoder is null.</exception>
         public static void Save<TPixel>(this Image<TPixel> source, string filePath, IImageEncoder encoder)
             where TPixel : struct, IPixel<TPixel>
         {
@@ -81,13 +81,13 @@ namespace SixLabors.ImageSharp
 #endif
 
         /// <summary>
-        /// Saves the image to the given stream using the currently loaded image format.
+        /// Writes the image to the given stream using the currently loaded image format.
         /// </summary>
         /// <typeparam name="TPixel">The Pixel format.</typeparam>
-        /// <param name="source">The source image</param>
+        /// <param name="source">The source image.</param>
         /// <param name="stream">The stream to save the image to.</param>
-        /// <param name="format">The format to save the image to.</param>
-        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        /// <param name="format">The format to save the image in.</param>
+        /// <exception cref="ArgumentNullException">Thrown if the stream is null.</exception>
         public static void Save<TPixel>(this Image<TPixel> source, Stream stream, IImageFormat format)
             where TPixel : struct, IPixel<TPixel>
         {
@@ -111,67 +111,67 @@ namespace SixLabors.ImageSharp
         }
 
         /// <summary>
-        /// Saves the raw image pixels to a byte array in row-major order.
+        /// Returns the a copy of the image pixels as a byte array in row-major order.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="source">The source image</param>
         /// <returns>A copy of the pixel data as bytes from this frame.</returns>
-        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        /// <exception cref="ArgumentNullException">Thrown if the stream is null.</exception>
         public static byte[] SavePixelData<TPixel>(this ImageFrame<TPixel> source)
             where TPixel : struct, IPixel<TPixel>
          => MemoryMarshal.AsBytes(source.GetPixelSpan()).ToArray();
 
         /// <summary>
-        /// Saves the raw image pixels to the given byte array in row-major order.
+        /// Writes the raw image pixels to the given byte array in row-major order.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
-        /// <param name="source">The source image</param>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
+        /// <param name="source">The source image.</param>
         /// <param name="buffer">The buffer to save the raw pixel data to.</param>
-        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        /// <exception cref="ArgumentNullException">Thrown if the stream is null.</exception>
         public static void SavePixelData<TPixel>(this ImageFrame<TPixel> source, byte[] buffer)
             where TPixel : struct, IPixel<TPixel>
             => SavePixelData(source, MemoryMarshal.Cast<byte, TPixel>(buffer.AsSpan()));
 
         /// <summary>
-        /// Saves the raw image pixels to the given TPixel array in row-major order.
+        /// Writes the raw image pixels to the given TPixel array in row-major order.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="source">The source image</param>
         /// <param name="buffer">The buffer to save the raw pixel data to.</param>
-        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        /// <exception cref="ArgumentNullException">Thrown if the stream is null.</exception>
         public static void SavePixelData<TPixel>(this ImageFrame<TPixel> source, TPixel[] buffer)
             where TPixel : struct, IPixel<TPixel>
             => SavePixelData(source, buffer.AsSpan());
 
         /// <summary>
-        /// Saves the raw image pixels to a byte array in row-major order.
+        /// Returns a copy of the raw image pixels as a byte array in row-major order.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
-        /// <param name="source">The source image</param>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
+        /// <param name="source">The source image.</param>
         /// <returns>A copy of the pixel data from the first frame as bytes.</returns>
-        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        /// <exception cref="ArgumentNullException">Thrown if the stream is null.</exception>
         public static byte[] SavePixelData<TPixel>(this Image<TPixel> source)
             where TPixel : struct, IPixel<TPixel>
          => source.Frames.RootFrame.SavePixelData();
 
         /// <summary>
-        /// Saves the raw image pixels to the given byte array in row-major order.
+        /// Writes the raw image pixels to the given byte array in row-major order.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
-        /// <param name="source">The source image</param>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
+        /// <param name="source">The source image.</param>
         /// <param name="buffer">The buffer to save the raw pixel data to.</param>
-        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        /// <exception cref="ArgumentNullException">Thrown if the stream is null.</exception>
         public static void SavePixelData<TPixel>(this Image<TPixel> source, byte[] buffer)
             where TPixel : struct, IPixel<TPixel>
             => source.Frames.RootFrame.SavePixelData(buffer);
 
         /// <summary>
-        /// Saves the raw image pixels to the given TPixel array in row-major order.
+        /// Writes the raw image pixels to the given TPixel array in row-major order.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="source">The source image</param>
         /// <param name="buffer">The buffer to save the raw pixel data to.</param>
-        /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
+        /// <exception cref="ArgumentNullException">Thrown if the stream is null.</exception>
         public static void SavePixelData<TPixel>(this Image<TPixel> source, TPixel[] buffer)
             where TPixel : struct, IPixel<TPixel>
             => source.Frames.RootFrame.SavePixelData(buffer);
@@ -180,7 +180,7 @@ namespace SixLabors.ImageSharp
         /// Returns a Base64 encoded string from the given image.
         /// </summary>
         /// <example><see href="data:image/gif;base64,R0lGODlhAQABAIABAEdJRgAAACwAAAAAAQABAAACAkQBAA=="/></example>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="source">The source image</param>
         /// <param name="format">The format.</param>
         /// <returns>The <see cref="string"/></returns>
@@ -196,22 +196,22 @@ namespace SixLabors.ImageSharp
         }
 
         /// <summary>
-        /// Saves the raw image to the given byte buffer.
+        /// Writes the raw image bytes to the given byte span.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="source">The source image</param>
-        /// <param name="buffer">The buffer to save the raw pixel data to.</param>
+        /// <param name="buffer">The span to save the raw pixel data to.</param>
         /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
         public static void SavePixelData<TPixel>(this Image<TPixel> source, Span<byte> buffer)
             where TPixel : struct, IPixel<TPixel>
             => source.Frames.RootFrame.SavePixelData(MemoryMarshal.Cast<byte, TPixel>(buffer));
 
         /// <summary>
-        /// Saves the raw image to the given byte buffer.
+        /// Writes the raw image pixels to the given TPixel span.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="source">The source image</param>
-        /// <param name="buffer">The buffer to save the raw pixel data to.</param>
+        /// <param name="buffer">The span to save the raw pixel data to.</param>
         /// <exception cref="System.ArgumentNullException">Thrown if the stream is null.</exception>
         public static void SavePixelData<TPixel>(this ImageFrame<TPixel> source, Span<TPixel> buffer)
             where TPixel : struct, IPixel<TPixel>

From 88098d741e075a0157e4d9ed5cbbae9f6a5653ec Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Fri, 11 May 2018 10:32:42 -0700
Subject: [PATCH 20/21] Update three more spans to ReadOnly

---
 src/ImageSharp/Formats/Png/Filters/NoneFilter.cs | 2 +-
 src/ImageSharp/ImageFrame.LoadPixelData.cs       | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/ImageSharp/Formats/Png/Filters/NoneFilter.cs b/src/ImageSharp/Formats/Png/Filters/NoneFilter.cs
index 0164ceafa..14af8ca6a 100644
--- a/src/ImageSharp/Formats/Png/Filters/NoneFilter.cs
+++ b/src/ImageSharp/Formats/Png/Filters/NoneFilter.cs
@@ -20,7 +20,7 @@ namespace SixLabors.ImageSharp.Formats.Png.Filters
         /// <param name="scanline">The scanline to encode</param>
         /// <param name="result">The filtered scanline result.</param>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static void Encode(Span<byte> scanline, Span<byte> result)
+        public static void Encode(ReadOnlySpan<byte> scanline, Span<byte> result)
         {
             // Insert a byte before the data.
             result[0] = 0;
diff --git a/src/ImageSharp/ImageFrame.LoadPixelData.cs b/src/ImageSharp/ImageFrame.LoadPixelData.cs
index 1306c2836..4639a104b 100644
--- a/src/ImageSharp/ImageFrame.LoadPixelData.cs
+++ b/src/ImageSharp/ImageFrame.LoadPixelData.cs
@@ -23,7 +23,7 @@ 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>(MemoryManager memoryManager, Span<byte> data, int width, int height)
+        public static ImageFrame<TPixel> LoadPixelData<TPixel>(MemoryManager memoryManager, ReadOnlySpan<byte> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
             => LoadPixelData(memoryManager, MemoryMarshal.Cast<byte, TPixel>(data), width, height);
 
@@ -36,7 +36,7 @@ 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>(MemoryManager memoryManager, Span<TPixel> data, int width, int height)
+        public static ImageFrame<TPixel> LoadPixelData<TPixel>(MemoryManager memoryManager, ReadOnlySpan<TPixel> data, int width, int height)
             where TPixel : struct, IPixel<TPixel>
         {
             int count = width * height;

From 609e7663a0a042ae7e90850deae76085c89910c4 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Fri, 11 May 2018 10:37:29 -0700
Subject: [PATCH 21/21] React to LoadPixelData change

---
 src/ImageSharp/ImageFrameCollection.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ImageSharp/ImageFrameCollection.cs b/src/ImageSharp/ImageFrameCollection.cs
index cacad34a4..be15a6527 100644
--- a/src/ImageSharp/ImageFrameCollection.cs
+++ b/src/ImageSharp/ImageFrameCollection.cs
@@ -117,7 +117,7 @@ namespace SixLabors.ImageSharp
 
             var frame = ImageFrame.LoadPixelData(
                 this.parent.GetMemoryManager(),
-                new Span<TPixel>(source),
+                new ReadOnlySpan<TPixel>(source),
                 this.RootFrame.Width,
                 this.RootFrame.Height);
             this.frames.Add(frame);