GetPixelRowMemory(), GetPixelRowSpan()

src/ImageSharp/Advanced/AdvancedImageExtensions.cs

@@ -24,7 +24,8 @@ namespace SixLabors.ImageSharp.Advanced
             => GetConfiguration((IConfigurable)source);
 
         /// <summary>
-        /// Gets the <see cref="Memory{T}"/> storing the whole pixel buffer in row major order.
+        /// Gets the representation of the pixels as a <see cref="Memory{T}"/> of contiguous memory in the source image's pixel format
+        /// stored in row major order.
         /// </summary>
         /// <typeparam name="TPixel">The Pixel format.</typeparam>
         /// <param name="source">The source <see cref="ImageFrame{TPixel}"/></param>
@@ -36,7 +37,8 @@ namespace SixLabors.ImageSharp.Advanced
         }
 
         /// <summary>
-        /// Gets the <see cref="Memory{T}"/> storing the whole pixel buffer in row major order.
+        /// Gets the representation of the pixels as a <see cref="Memory{T}"/> of contiguous memory in the source image's pixel format
+        /// stored in row major order.
         /// </summary>
         /// <typeparam name="TPixel">The Pixel format.</typeparam>
         /// <param name="source">The source <see cref="Image{TPixel}"/></param>
@@ -48,70 +50,98 @@ namespace SixLabors.ImageSharp.Advanced
         }
 
         /// <summary>
-        /// Returns a reference to the 0th element of the Pixel buffer,
-        /// allowing direct manipulation of pixel data through unsafe operations.
-        /// The pixel buffer is a contiguous memory area containing Width*Height TPixel elements laid out in row-major order.
+        /// Gets the representation of the pixels as a <see cref="Span{T}"/> of contiguous memory in the source image's pixel format
+        /// stored in row major order.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
-        /// <param name="source">The source image frame</param>
-        /// <returns>A pinnable reference the first root of the pixel buffer.</returns>
-        public static ref TPixel DangerousGetPinnableReferenceToPixelBuffer<TPixel>(this ImageFrame<TPixel> source)
+        /// <typeparam name="TPixel">The type of the pixel.</typeparam>
+        /// <param name="source">The source.</param>
+        /// <returns>The <see cref="Span{TPixel}"/></returns>
+        public static Span<TPixel> GetPixelSpan<TPixel>(this ImageFrame<TPixel> source)
             where TPixel : struct, IPixel<TPixel>
-         => ref DangerousGetPinnableReferenceToPixelBuffer((IPixelSource<TPixel>)source);
+            => source.GetPixelMemory().Span;
 
         /// <summary>
-        /// Returns a reference to the 0th element of the Pixel buffer,
-        /// allowing direct manipulation of pixel data through unsafe operations.
-        /// The pixel buffer is a contigous memory area containing Width*Height TPixel elements layed out in row-major order.
+        /// Gets the representation of the pixels as a <see cref="Span{T}"/> of contiguous memory in the source image's pixel format
+        /// stored in row major order.
         /// </summary>
-        /// <typeparam name="TPixel">The Pixel format.</typeparam>
-        /// <param name="source">The source image</param>
-        /// <returns>A pinnable reference the first root of the pixel buffer.</returns>
-        public static ref TPixel DangerousGetPinnableReferenceToPixelBuffer<TPixel>(this Image<TPixel> source)
+        /// <typeparam name="TPixel">The type of the pixel.</typeparam>
+        /// <param name="source">The source.</param>
+        /// <returns>The <see cref="Span{TPixel}"/></returns>
+        public static Span<TPixel> GetPixelSpan<TPixel>(this Image<TPixel> source)
             where TPixel : struct, IPixel<TPixel>
-         => ref source.Frames.RootFrame.DangerousGetPinnableReferenceToPixelBuffer();
+            => source.Frames.RootFrame.GetPixelSpan();
 
         /// <summary>
-        /// Gets the representation of the pixels as an area of contiguous memory in the given pixel format.
+        /// Gets the representation of the pixels as a <see cref="Span{T}"/> of contiguous memory
+        /// at row <paramref name="rowIndex"/> beginning from the the first pixel on that row.
         /// </summary>
         /// <typeparam name="TPixel">The type of the pixel.</typeparam>
         /// <param name="source">The source.</param>
+        /// <param name="rowIndex">The row.</param>
         /// <returns>The <see cref="Span{TPixel}"/></returns>
-        internal static Span<TPixel> GetPixelSpan<TPixel>(this ImageFrame<TPixel> source)
+        public static Memory<TPixel> GetPixelRowMemory<TPixel>(this ImageFrame<TPixel> source, int rowIndex)
             where TPixel : struct, IPixel<TPixel>
-            => GetSpan(source);
+            => source.PixelBuffer.GetRowMemory(rowIndex);
 
         /// <summary>
-        /// Gets the representation of the pixels as an area of contiguous memory at row 'y' beginning from the the first pixel on that row.
+        /// Gets the representation of the pixels as <see cref="Span{T}"/> of of contiguous memory
+        /// at row <paramref name="rowIndex"/> beginning from the the first pixel on that row.
         /// </summary>
         /// <typeparam name="TPixel">The type of the pixel.</typeparam>
         /// <param name="source">The source.</param>
-        /// <param name="row">The row.</param>
+        /// <param name="rowIndex">The row.</param>
         /// <returns>The <see cref="Span{TPixel}"/></returns>
-        internal static Span<TPixel> GetPixelRowSpan<TPixel>(this ImageFrame<TPixel> source, int row)
+        public static Memory<TPixel> GetPixelRowMemory<TPixel>(this Image<TPixel> source, int rowIndex)
             where TPixel : struct, IPixel<TPixel>
-            => GetSpan(source, row);
+            => source.Frames.RootFrame.GetPixelRowMemory(rowIndex);
 
         /// <summary>
-        /// Gets the representation of the pixels as an area of contiguous memory in the given pixel format.
+        /// Gets the representation of the pixels as a <see cref="Span{T}"/> of contiguous memory
+        /// at row <paramref name="rowIndex"/> beginning from the the first pixel on that row.
         /// </summary>
         /// <typeparam name="TPixel">The type of the pixel.</typeparam>
         /// <param name="source">The source.</param>
+        /// <param name="rowIndex">The row.</param>
         /// <returns>The <see cref="Span{TPixel}"/></returns>
-        internal static Span<TPixel> GetPixelSpan<TPixel>(this Image<TPixel> source)
+        public static Span<TPixel> GetPixelRowSpan<TPixel>(this ImageFrame<TPixel> source, int rowIndex)
             where TPixel : struct, IPixel<TPixel>
-            => source.Frames.RootFrame.GetPixelSpan();
+            => source.PixelBuffer.GetRowSpan(rowIndex);
 
         /// <summary>
-        /// Gets the representation of the pixels as an area of contiguous memory at row 'y' beginning from the the first pixel on that row.
+        /// Gets the representation of the pixels as <see cref="Span{T}"/> of of contiguous memory
+        /// at row <paramref name="rowIndex"/> beginning from the the first pixel on that row.
         /// </summary>
         /// <typeparam name="TPixel">The type of the pixel.</typeparam>
         /// <param name="source">The source.</param>
-        /// <param name="row">The row.</param>
+        /// <param name="rowIndex">The row.</param>
         /// <returns>The <see cref="Span{TPixel}"/></returns>
-        internal static Span<TPixel> GetPixelRowSpan<TPixel>(this Image<TPixel> source, int row)
+        public static Span<TPixel> GetPixelRowSpan<TPixel>(this Image<TPixel> source, int rowIndex)
+            where TPixel : struct, IPixel<TPixel>
+            => source.Frames.RootFrame.GetPixelRowSpan(rowIndex);
+
+        /// <summary>
+        /// Returns a reference to the 0th element of the Pixel buffer,
+        /// allowing direct manipulation of pixel data through unsafe operations.
+        /// The pixel buffer is a contiguous memory area containing Width*Height TPixel elements laid out in row-major order.
+        /// </summary>
+        /// <typeparam name="TPixel">The Pixel format.</typeparam>
+        /// <param name="source">The source image frame</param>
+        /// <returns>A pinnable reference the first root of the pixel buffer.</returns>
+        public static ref TPixel DangerousGetPinnableReferenceToPixelBuffer<TPixel>(this ImageFrame<TPixel> source)
+            where TPixel : struct, IPixel<TPixel>
+            => ref DangerousGetPinnableReferenceToPixelBuffer((IPixelSource<TPixel>)source);
+
+        /// <summary>
+        /// Returns a reference to the 0th element of the Pixel buffer,
+        /// allowing direct manipulation of pixel data through unsafe operations.
+        /// The pixel buffer is a contigous memory area containing Width*Height TPixel elements layed out in row-major order.
+        /// </summary>
+        /// <typeparam name="TPixel">The Pixel format.</typeparam>
+        /// <param name="source">The source image</param>
+        /// <returns>A pinnable reference the first root of the pixel buffer.</returns>
+        public static ref TPixel DangerousGetPinnableReferenceToPixelBuffer<TPixel>(this Image<TPixel> source)
             where TPixel : struct, IPixel<TPixel>
-            => source.Frames.RootFrame.GetPixelRowSpan(row);
+            => ref source.Frames.RootFrame.DangerousGetPinnableReferenceToPixelBuffer();
 
         /// <summary>
         /// Gets the <see cref="MemoryManager"/> assigned to 'source'.

src/ImageSharp/Memory/Buffer2DExtensions.cs

@@ -50,6 +50,20 @@ namespace SixLabors.ImageSharp.Memory
             return buffer.GetSpan().Slice(y * buffer.Width, buffer.Width);
         }
 
+        /// <summary>
+        /// Gets a <see cref="Memory{T}"/> to the row 'y' beginning from the pixel at the first pixel on that row.
+        /// </summary>
+        /// <param name="buffer">The buffer</param>
+        /// <param name="y">The y (row) coordinate</param>
+        /// <typeparam name="T">The element type</typeparam>
+        /// <returns>The <see cref="Span{T}"/></returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static Memory<T> GetRowMemory<T>(this IBuffer2D<T> buffer, int y)
+            where T : struct
+        {
+            return buffer.Buffer.Memory.Slice(y * buffer.Width, buffer.Width);
+        }
+
         /// <summary>
         /// Returns the size of the buffer.
         /// </summary>

tests/ImageSharp.Tests/Advanced/AdvancedImageExtensionsTests.cs

@@ -21,20 +21,77 @@ namespace SixLabors.ImageSharp.Tests.Advanced
             public void WhenMemoryIsOwned<TPixel>(TestImageProvider<TPixel> provider)
                 where TPixel : struct, IPixel<TPixel>
             {
-                using (Image<TPixel> image = provider.GetImage())
+                using (Image<TPixel> image0 = provider.GetImage())
                 {
-                    Memory<TPixel> memory = image.GetPixelMemory();
-                    Assert.Equal(image.Width * image.Height, memory.Length);
+                    var targetBuffer = new TPixel[image0.Width * image0.Height];
 
-                    var targetBuffer = new TPixel[image.Width * image.Height];
+                    // Act:
+                    Memory<TPixel> memory = image0.GetPixelMemory();
+
+                    // Assert:
+                    Assert.Equal(image0.Width * image0.Height, memory.Length);
                     memory.Span.CopyTo(targetBuffer);
 
-                    image.ComparePixelBufferTo(targetBuffer);
+                    using (Image<TPixel> image1 = provider.GetImage())
+                    {
+                        // We are using a copy of the original image for assertion
+                        image1.ComparePixelBufferTo(targetBuffer);
+                    }
+                }
+            }
+        }
+
+        [Theory]
+        [WithSolidFilledImages(1, 1, "Red", PixelTypes.Rgba32)]
+        [WithTestPatternImages(131, 127, PixelTypes.Rgba32 | PixelTypes.Bgr24)]
+        public void GetPixelRowMemory<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : struct, IPixel<TPixel>
+        {
+            using (Image<TPixel> image = provider.GetImage())
+            {
+                var targetBuffer = new TPixel[image.Width * image.Height];
+
+                // Act:
+                for (int y = 0; y < image.Height; y++)
+                {
+                    Memory<TPixel> rowMemory = image.GetPixelRowMemory(y);
+                    rowMemory.Span.CopyTo(targetBuffer.AsSpan(image.Width * y));
+                }
+
+                // Assert:
+                using (Image<TPixel> image1 = provider.GetImage())
+                {
+                    // We are using a copy of the original image for assertion
+                    image1.ComparePixelBufferTo(targetBuffer);
                 }
             }
         }
 
-        
+        [Theory]
+        [WithSolidFilledImages(1, 1, "Red", PixelTypes.Rgba32)]
+        [WithTestPatternImages(131, 127, PixelTypes.Rgba32 | PixelTypes.Bgr24)]
+        public void GetPixelRowSpan<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : struct, IPixel<TPixel>
+        {
+            using (Image<TPixel> image = provider.GetImage())
+            {
+                var targetBuffer = new TPixel[image.Width * image.Height];
+
+                // Act:
+                for (int y = 0; y < image.Height; y++)
+                {
+                    Span<TPixel> rowMemory = image.GetPixelRowSpan(y);
+                    rowMemory.CopyTo(targetBuffer.AsSpan(image.Width * y));
+                }
+
+                // Assert:
+                using (Image<TPixel> image1 = provider.GetImage())
+                {
+                    // We are using a copy of the original image for assertion
+                    image1.ComparePixelBufferTo(targetBuffer);
+                }
+            }
+        }
 
         [Theory]
         [WithTestPatternImages(131, 127, PixelTypes.Rgba32 | PixelTypes.Bgr24)]