From cad87f6cddedcf437214b89bc26f4d4f33559cfb Mon Sep 17 00:00:00 2001
From: Scott Williams <tocsoft@gmail.com>
Date: Fri, 19 May 2017 13:56:13 +0100
Subject: [PATCH] updated to make better use of Span<T>

---
 src/ImageSharp/Image/Image.LoadPixelData.cs   | 40 +++++--------------
 .../PixelFormats/PixelOperations{TPixel}.cs   | 22 ----------
 2 files changed, 10 insertions(+), 52 deletions(-)

diff --git a/src/ImageSharp/Image/Image.LoadPixelData.cs b/src/ImageSharp/Image/Image.LoadPixelData.cs
index fd7979190..75aa318be 100644
--- a/src/ImageSharp/Image/Image.LoadPixelData.cs
+++ b/src/ImageSharp/Image/Image.LoadPixelData.cs
@@ -14,49 +14,36 @@ namespace ImageSharp
     using ImageSharp.PixelFormats;
 
     /// <content>
-    /// Adds static methods allowing the creation of new image from a byte array.
+    /// Adds static methods allowing the creation of new image from raw pixel data.
     /// </content>
     public static partial class Image
     {
         /// <summary>
-        /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given pixel data.
+        /// Create a new instance of the <see cref="Image{TPixel}"/> class from the raw <typeparamref name="TPixel"/> data.
         /// </summary>
         /// <param name="data">The byte array containing image data.</param>
         /// <param name="width">The width of the final image.</param>
         /// <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>(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);
 
         /// <summary>
-        /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given pixel data.
-        /// </summary>
-        /// <param name="config">The config for the decoder.</param>
-        /// <param name="data">The byte array containing image data.</param>
-        /// <param name="width">The width of the final image.</param>
-        /// <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, TPixel[] data, int width, int height)
-            where TPixel : struct, IPixel<TPixel>
-            => LoadPixelData(config, new Span<TPixel>(data), width, height);
-
-        /// <summary>
-        /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given byte array as raw pixel data.
+        /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given byte array in <typeparamref name="TPixel"/> format.
         /// </summary>
         /// <param name="data">The byte array containing image data.</param>
         /// <param name="width">The width of the final image.</param>
         /// <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>(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);
 
         /// <summary>
-        /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given byte array as raw pixel data.
+        /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given byte array in <typeparamref name="TPixel"/> format.
         /// </summary>
         /// <param name="config">The config for the decoder.</param>
         /// <param name="data">The byte array containing image data.</param>
@@ -64,19 +51,12 @@ namespace 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, 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>
-        {
-            int size = width * height;
-            using (var sourceBuffer = new Buffer<TPixel>(size))
-            {
-                PixelOperations<TPixel>.Instance.PackFromRawBytes(new Span<byte>(data), sourceBuffer.Span, size);
-                return LoadPixelData(config, sourceBuffer.Span, width, height);
-            }
-        }
+            => LoadPixelData(config, data.NonPortableCast<byte, TPixel>(), width, height);
 
         /// <summary>
-        /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given byte array as raw pixel data.
+        /// Create a new instance of the <see cref="Image{TPixel}"/> class from the raw <typeparamref name="TPixel"/> data.
         /// </summary>
         /// <param name="config">The config for the decoder.</param>
         /// <param name="data">The Span containing the image Pixel data.</param>
@@ -84,7 +64,7 @@ namespace 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;
diff --git a/src/ImageSharp/PixelFormats/PixelOperations{TPixel}.cs b/src/ImageSharp/PixelFormats/PixelOperations{TPixel}.cs
index b29af94ee..993a11232 100644
--- a/src/ImageSharp/PixelFormats/PixelOperations{TPixel}.cs
+++ b/src/ImageSharp/PixelFormats/PixelOperations{TPixel}.cs
@@ -249,27 +249,5 @@ namespace ImageSharp.PixelFormats
                 sp.ToZyxwBytes(destBytes, i * 4);
             }
         }
-
-        /// <summary>
-        /// Bulk conversion of data from series bytes to a series of Pixels.
-        /// </summary>
-        /// <param name="sourceBytes">The <see cref="Span{T}"/> to the source bytes.</param>
-        /// <param name="destColors">The <see cref="Span{T}"/> to the destination colors.</param>
-        /// <param name="count">The number of pixels to convert.</param>
-        internal virtual void PackFromRawBytes(Span<byte> sourceBytes, Span<TPixel> destColors, int count)
-        {
-            Guard.MustBeSizedAtLeast(sourceBytes, count * Unsafe.SizeOf<TPixel>(), nameof(sourceBytes));
-            Guard.MustBeSizedAtLeast(destColors, count, nameof(destColors));
-
-            ref TPixel sourceRef = ref Unsafe.As<byte, TPixel>(ref sourceBytes.DangerousGetPinnableReference());
-            ref TPixel destRef = ref destColors.DangerousGetPinnableReference();
-
-            for (int i = 0; i < count; i++)
-            {
-                ref TPixel sp = ref Unsafe.Add(ref sourceRef, i);
-                ref TPixel dp = ref Unsafe.Add(ref destRef, i);
-                dp = sp;
-            }
-        }
     }
 }
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