merge back GetRowSpan and GetRowSpanUnchecked

src/ImageSharp/Advanced/AdvancedImageExtensions.cs

@@ -135,7 +135,7 @@ namespace SixLabors.ImageSharp.Advanced
             Guard.MustBeGreaterThanOrEqualTo(rowIndex, 0, nameof(rowIndex));
             Guard.MustBeLessThan(rowIndex, source.Height, nameof(rowIndex));
 
-            return source.PixelBuffer.GetRowSpanUnchecked(rowIndex);
+            return source.PixelBuffer.GetRowSpan(rowIndex);
         }
 
         /// <summary>
@@ -153,7 +153,7 @@ namespace SixLabors.ImageSharp.Advanced
             Guard.MustBeGreaterThanOrEqualTo(rowIndex, 0, nameof(rowIndex));
             Guard.MustBeLessThan(rowIndex, source.Height, nameof(rowIndex));
 
-            return source.Frames.RootFrame.PixelBuffer.GetRowSpanUnchecked(rowIndex);
+            return source.Frames.RootFrame.PixelBuffer.GetRowSpan(rowIndex);
         }
 
         /// <summary>
@@ -171,7 +171,7 @@ namespace SixLabors.ImageSharp.Advanced
             Guard.MustBeGreaterThanOrEqualTo(rowIndex, 0, nameof(rowIndex));
             Guard.MustBeLessThan(rowIndex, source.Height, nameof(rowIndex));
 
-            return source.PixelBuffer.GetRowMemorySafe(rowIndex);
+            return source.PixelBuffer.GetSafeRowMemory(rowIndex);
         }
 
         /// <summary>
@@ -189,7 +189,7 @@ namespace SixLabors.ImageSharp.Advanced
             Guard.MustBeGreaterThanOrEqualTo(rowIndex, 0, nameof(rowIndex));
             Guard.MustBeLessThan(rowIndex, source.Height, nameof(rowIndex));
 
-            return source.Frames.RootFrame.PixelBuffer.GetRowMemorySafe(rowIndex);
+            return source.Frames.RootFrame.PixelBuffer.GetSafeRowMemory(rowIndex);
         }
 
         /// <summary>

src/ImageSharp/Common/Helpers/Buffer2DUtils.cs

@@ -52,7 +52,7 @@ namespace SixLabors.ImageSharp
             {
                 int offsetY = (row + i - radiusY).Clamp(minRow, maxRow);
                 int offsetX = sourceOffsetColumnBase.Clamp(minColumn, maxColumn);
-                Span<TPixel> sourceRowSpan = sourcePixels.GetRowSpanUnchecked(offsetY);
+                Span<TPixel> sourceRowSpan = sourcePixels.GetRowSpan(offsetY);
                 var currentColor = sourceRowSpan[offsetX].ToVector4();
 
                 vector.Sum(Unsafe.Add(ref baseRef, i) * currentColor);
@@ -94,7 +94,7 @@ namespace SixLabors.ImageSharp
             int sourceOffsetColumnBase = column + minColumn;
 
             int offsetY = row.Clamp(minRow, maxRow);
-            ref ComplexVector4 sourceRef = ref MemoryMarshal.GetReference(sourceValues.GetRowSpanUnchecked(offsetY));
+            ref ComplexVector4 sourceRef = ref MemoryMarshal.GetReference(sourceValues.GetRowSpan(offsetY));
             ref Complex64 baseRef = ref MemoryMarshal.GetReference(kernel);
 
             for (int x = 0; x < kernelLength; x++)

src/ImageSharp/Common/Helpers/DenseMatrixUtils.cs

@@ -134,7 +134,7 @@ namespace SixLabors.ImageSharp
             for (int y = 0; y < matrixHeight; y++)
             {
                 int offsetY = (row + y - radiusY).Clamp(minRow, maxRow);
-                Span<TPixel> sourceRowSpan = sourcePixels.GetRowSpanUnchecked(offsetY);
+                Span<TPixel> sourceRowSpan = sourcePixels.GetRowSpan(offsetY);
 
                 for (int x = 0; x < matrixWidth; x++)
                 {
@@ -264,7 +264,7 @@ namespace SixLabors.ImageSharp
             for (int y = 0; y < matrixHeight; y++)
             {
                 int offsetY = (row + y - radiusY).Clamp(minRow, maxRow);
-                Span<TPixel> sourceRowSpan = sourcePixels.GetRowSpanUnchecked(offsetY);
+                Span<TPixel> sourceRowSpan = sourcePixels.GetRowSpan(offsetY);
 
                 for (int x = 0; x < matrixWidth; x++)
                 {

src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs

@@ -320,7 +320,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                     int newY = Invert(y, height, inverted);
                     int rowStartIdx = y * width;
                     Span<byte> bufferRow = bufferSpan.Slice(rowStartIdx, width);
-                    Span<TPixel> pixelRow = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
 
                     bool rowHasUndefinedPixels = rowsWithUndefinedPixelsSpan[y];
                     if (rowHasUndefinedPixels)
@@ -391,7 +391,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                 for (int y = 0; y < height; y++)
                 {
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelRow = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
                     bool rowHasUndefinedPixels = rowsWithUndefinedPixelsSpan[y];
                     if (rowHasUndefinedPixels)
                     {
@@ -841,7 +841,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                     int newY = Invert(y, height, inverted);
                     this.stream.Read(row.Array, 0, row.Length());
                     int offset = 0;
-                    Span<TPixel> pixelRow = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
 
                     for (int x = 0; x < arrayWidth; x++)
                     {
@@ -893,7 +893,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                 {
                     this.stream.Read(buffer.Array, 0, stride);
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelRow = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
 
                     int offset = 0;
                     for (int x = 0; x < width; x++)
@@ -949,7 +949,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                 {
                     this.stream.Read(row);
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
                     PixelOperations<TPixel>.Instance.FromBgr24Bytes(
                         this.configuration,
                         row.GetSpan(),
@@ -978,7 +978,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                 {
                     this.stream.Read(row);
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
                     PixelOperations<TPixel>.Instance.FromBgra32Bytes(
                         this.configuration,
                         row.GetSpan(),
@@ -1050,7 +1050,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                         this.stream.Read(row);
 
                         int newY = Invert(y, height, inverted);
-                        Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(newY);
+                        Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
 
                         PixelOperations<TPixel>.Instance.FromBgra32Bytes(
                             this.configuration,
@@ -1073,7 +1073,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                         width);
 
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
 
                     for (int x = 0; x < width; x++)
                     {
@@ -1128,7 +1128,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
                 {
                     this.stream.Read(buffer.Array, 0, stride);
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelRow = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
 
                     int offset = 0;
                     for (int x = 0; x < width; x++)

src/ImageSharp/Formats/Bmp/BmpEncoderCore.cs

@@ -240,7 +240,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
             {
                 for (int y = pixels.Height - 1; y >= 0; y--)
                 {
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(y);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(y);
                     PixelOperations<TPixel>.Instance.ToBgra32Bytes(
                         this.configuration,
                         pixelSpan,
@@ -264,7 +264,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
             {
                 for (int y = pixels.Height - 1; y >= 0; y--)
                 {
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(y);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(y);
                     PixelOperations<TPixel>.Instance.ToBgr24Bytes(
                         this.configuration,
                         pixelSpan,
@@ -288,7 +288,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
             {
                 for (int y = pixels.Height - 1; y >= 0; y--)
                 {
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(y);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(y);
 
                     PixelOperations<TPixel>.Instance.ToBgra5551Bytes(
                         this.configuration,

src/ImageSharp/Formats/Jpeg/Components/Decoder/ColorConverters/JpegColorConverter.cs

@@ -136,20 +136,20 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder.ColorConverters
             {
                 this.ComponentCount = componentBuffers.Count;
 
-                this.Component0 = componentBuffers[0].GetRowSpanUnchecked(row);
+                this.Component0 = componentBuffers[0].GetRowSpan(row);
                 this.Component1 = Span<float>.Empty;
                 this.Component2 = Span<float>.Empty;
                 this.Component3 = Span<float>.Empty;
 
                 if (this.ComponentCount > 1)
                 {
-                    this.Component1 = componentBuffers[1].GetRowSpanUnchecked(row);
+                    this.Component1 = componentBuffers[1].GetRowSpan(row);
                     if (this.ComponentCount > 2)
                     {
-                        this.Component2 = componentBuffers[2].GetRowSpanUnchecked(row);
+                        this.Component2 = componentBuffers[2].GetRowSpan(row);
                         if (this.ComponentCount > 3)
                         {
-                            this.Component3 = componentBuffers[3].GetRowSpanUnchecked(row);
+                            this.Component3 = componentBuffers[3].GetRowSpan(row);
                         }
                     }
                 }

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

@@ -167,7 +167,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
                         for (int y = 0; y < v; y++)
                         {
                             int blockRow = (mcuRow * v) + y;
-                            Span<Block8x8> blockSpan = component.SpectralBlocks.GetRowSpanUnchecked(blockRow);
+                            Span<Block8x8> blockSpan = component.SpectralBlocks.GetRowSpan(blockRow);
                             ref Block8x8 blockRef = ref MemoryMarshal.GetReference(blockSpan);
 
                             for (int x = 0; x < h; x++)
@@ -211,7 +211,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
 
             for (int j = 0; j < h; j++)
             {
-                Span<Block8x8> blockSpan = component.SpectralBlocks.GetRowSpanUnchecked(j);
+                Span<Block8x8> blockSpan = component.SpectralBlocks.GetRowSpan(j);
                 ref Block8x8 blockRef = ref MemoryMarshal.GetReference(blockSpan);
 
                 for (int i = 0; i < w; i++)
@@ -334,7 +334,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
                         for (int y = 0; y < v; y++)
                         {
                             int blockRow = (mcuRow * v) + y;
-                            Span<Block8x8> blockSpan = component.SpectralBlocks.GetRowSpanUnchecked(blockRow);
+                            Span<Block8x8> blockSpan = component.SpectralBlocks.GetRowSpan(blockRow);
                             ref Block8x8 blockRef = ref MemoryMarshal.GetReference(blockSpan);
 
                             for (int x = 0; x < h; x++)
@@ -377,7 +377,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
 
                 for (int j = 0; j < h; j++)
                 {
-                    Span<Block8x8> blockSpan = component.SpectralBlocks.GetRowSpanUnchecked(j);
+                    Span<Block8x8> blockSpan = component.SpectralBlocks.GetRowSpan(j);
                     ref Block8x8 blockRef = ref MemoryMarshal.GetReference(blockSpan);
 
                     for (int i = 0; i < w; i++)
@@ -403,7 +403,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
 
                 for (int j = 0; j < h; j++)
                 {
-                    Span<Block8x8> blockSpan = component.SpectralBlocks.GetRowSpanUnchecked(j);
+                    Span<Block8x8> blockSpan = component.SpectralBlocks.GetRowSpan(j);
                     ref Block8x8 blockRef = ref MemoryMarshal.GetReference(blockSpan);
 
                     for (int i = 0; i < w; i++)

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

@@ -89,7 +89,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
 
                 int yBuffer = y * this.blockAreaSize.Height;
 
-                Span<Block8x8> blockRow = this.Component.SpectralBlocks.GetRowSpanUnchecked(yBlock);
+                Span<Block8x8> blockRow = this.Component.SpectralBlocks.GetRowSpan(yBlock);
 
                 ref Block8x8 blockRowBase = ref MemoryMarshal.GetReference(blockRow);
 

src/ImageSharp/Formats/Jpeg/Components/RowOctet.cs

@@ -27,14 +27,14 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
         {
             int y = startY;
             int height = buffer.Height;
-            this.row0 = y < height ? buffer.GetRowSpanUnchecked(y++) : default;
+            this.row0 = y < height ? buffer.GetRowSpan(y++) : default;
-            this.row1 = y < height ? buffer.GetRowSpanUnchecked(y++) : default;
+            this.row1 = y < height ? buffer.GetRowSpan(y++) : default;
-            this.row2 = y < height ? buffer.GetRowSpanUnchecked(y++) : default;
+            this.row2 = y < height ? buffer.GetRowSpan(y++) : default;
-            this.row3 = y < height ? buffer.GetRowSpanUnchecked(y++) : default;
+            this.row3 = y < height ? buffer.GetRowSpan(y++) : default;
-            this.row4 = y < height ? buffer.GetRowSpanUnchecked(y++) : default;
+            this.row4 = y < height ? buffer.GetRowSpan(y++) : default;
-            this.row5 = y < height ? buffer.GetRowSpanUnchecked(y++) : default;
+            this.row5 = y < height ? buffer.GetRowSpan(y++) : default;
-            this.row6 = y < height ? buffer.GetRowSpanUnchecked(y++) : default;
+            this.row6 = y < height ? buffer.GetRowSpan(y++) : default;
-            this.row7 = y < height ? buffer.GetRowSpanUnchecked(y) : default;
+            this.row7 = y < height ? buffer.GetRowSpan(y) : default;
         }
 
         public Span<T> this[int y]

src/ImageSharp/Formats/Tga/TgaDecoderCore.cs

@@ -233,7 +233,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
                 {
                     this.currentStream.Read(row);
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelRow = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
                     switch (colorMapPixelSizeInBytes)
                     {
                         case 2:
@@ -297,7 +297,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
                 for (int y = 0; y < height; y++)
                 {
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelRow = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
                     int rowStartIdx = y * width * bytesPerPixel;
                     for (int x = 0; x < width; x++)
                     {
@@ -344,7 +344,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
                 {
                     this.currentStream.Read(row);
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
                     PixelOperations<TPixel>.Instance.FromL8Bytes(
                         this.configuration,
                         row.GetSpan(),
@@ -379,7 +379,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
                     }
 
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
                     PixelOperations<TPixel>.Instance.FromBgra5551Bytes(
                         this.configuration,
                         rowSpan,
@@ -406,7 +406,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
                 {
                     this.currentStream.Read(row);
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
                     PixelOperations<TPixel>.Instance.FromBgr24Bytes(
                         this.configuration,
                         row.GetSpan(),
@@ -433,7 +433,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
                 {
                     this.currentStream.Read(row);
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(newY);
                     PixelOperations<TPixel>.Instance.FromBgra32Bytes(
                         this.configuration,
                         row.GetSpan(),
@@ -463,7 +463,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
                 for (int y = 0; y < height; y++)
                 {
                     int newY = Invert(y, height, inverted);
-                    Span<TPixel> pixelRow = pixels.GetRowSpanUnchecked(newY);
+                    Span<TPixel> pixelRow = pixels.GetRowSpan(newY);
                     int rowStartIdx = y * width * bytesPerPixel;
                     for (int x = 0; x < width; x++)
                     {

src/ImageSharp/Formats/Tga/TgaEncoderCore.cs

@@ -255,7 +255,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
             {
                 for (int y = pixels.Height - 1; y >= 0; y--)
                 {
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(y);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(y);
                     PixelOperations<TPixel>.Instance.ToL8Bytes(
                         this.configuration,
                         pixelSpan,
@@ -279,7 +279,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
             {
                 for (int y = pixels.Height - 1; y >= 0; y--)
                 {
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(y);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(y);
                     PixelOperations<TPixel>.Instance.ToBgra5551Bytes(
                         this.configuration,
                         pixelSpan,
@@ -303,7 +303,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
             {
                 for (int y = pixels.Height - 1; y >= 0; y--)
                 {
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(y);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(y);
                     PixelOperations<TPixel>.Instance.ToBgr24Bytes(
                         this.configuration,
                         pixelSpan,
@@ -327,7 +327,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
             {
                 for (int y = pixels.Height - 1; y >= 0; y--)
                 {
-                    Span<TPixel> pixelSpan = pixels.GetRowSpanUnchecked(y);
+                    Span<TPixel> pixelSpan = pixels.GetRowSpan(y);
                     PixelOperations<TPixel>.Instance.ToBgra32Bytes(
                         this.configuration,
                         pixelSpan,

src/ImageSharp/ImageFrame{TPixel}.cs

@@ -150,11 +150,19 @@ namespace SixLabors.ImageSharp
         /// <returns>The <see typeparam="TPixel"/> at the specified position.</returns>
         public TPixel this[int x, int y]
         {
-            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            [MethodImpl(InliningOptions.ShortMethod)]
-            get => this.PixelBuffer[x, y];
+            get
+            {
+                this.VerifyCoords(x, y);
+                return this.PixelBuffer.GetElementUnsafe(x, y);
+            }
 
-            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            [MethodImpl(InliningOptions.ShortMethod)]
-            set => this.PixelBuffer[x, y] = value;
+            set
+            {
+                this.VerifyCoords(x, y);
+                this.PixelBuffer.GetElementUnsafe(x, y) = value;
+            }
         }
 
         /// <summary>
@@ -287,6 +295,26 @@ namespace SixLabors.ImageSharp
             }
         }
 
+        [MethodImpl(InliningOptions.ShortMethod)]
+        private void VerifyCoords(int x, int y)
+        {
+            if (x < 0 || x >= this.Width)
+            {
+                ThrowArgumentOutOfRangeException(nameof(x));
+            }
+
+            if (y < 0 || y >= this.Height)
+            {
+                ThrowArgumentOutOfRangeException(nameof(y));
+            }
+        }
+
+        [MethodImpl(InliningOptions.ColdPath)]
+        private static void ThrowArgumentOutOfRangeException(string paramName)
+        {
+            throw new ArgumentOutOfRangeException(paramName);
+        }
+
         /// <summary>
         /// A <see langword="struct"/> implementing the clone logic for <see cref="ImageFrame{TPixel}"/>.
         /// </summary>

src/ImageSharp/Image{TPixel}.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Memory;
@@ -146,8 +147,19 @@ namespace SixLabors.ImageSharp
         /// <returns>The <see typeparam="TPixel"/> at the specified position.</returns>
         public TPixel this[int x, int y]
         {
-            get => this.PixelSource.PixelBuffer[x, y];
+            [MethodImpl(InliningOptions.ShortMethod)]
-            set => this.PixelSource.PixelBuffer[x, y] = value;
+            get
+            {
+                this.VerifyCoords(x, y);
+                return this.PixelSource.PixelBuffer.GetElementUnsafe(x, y);
+            }
+
+            [MethodImpl(InliningOptions.ShortMethod)]
+            set
+            {
+                this.VerifyCoords(x, y);
+                this.PixelSource.PixelBuffer.GetElementUnsafe(x, y) = value;
+            }
         }
 
         /// <summary>
@@ -265,5 +277,25 @@ namespace SixLabors.ImageSharp
 
             return rootSize;
         }
+
+        [MethodImpl(InliningOptions.ShortMethod)]
+        private void VerifyCoords(int x, int y)
+        {
+            if (x < 0 || x >= this.Width)
+            {
+                ThrowArgumentOutOfRangeException(nameof(x));
+            }
+
+            if (y < 0 || y >= this.Height)
+            {
+                ThrowArgumentOutOfRangeException(nameof(y));
+            }
+        }
+
+        [MethodImpl(InliningOptions.ColdPath)]
+        private static void ThrowArgumentOutOfRangeException(string paramName)
+        {
+            throw new ArgumentOutOfRangeException(paramName);
+        }
     }
 }

src/ImageSharp/Memory/Buffer2D{T}.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 
 namespace SixLabors.ImageSharp.Memory
 {
@@ -68,29 +69,15 @@ namespace SixLabors.ImageSharp.Memory
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             get
             {
+                DebugGuard.MustBeGreaterThanOrEqualTo(x, 0, nameof(x));
+                DebugGuard.MustBeGreaterThanOrEqualTo(y, 0, nameof(y));
                 DebugGuard.MustBeLessThan(x, this.Width, nameof(x));
                 DebugGuard.MustBeLessThan(y, this.Height, nameof(y));
 
-                return ref this.GetRowSpanUnchecked(y)[x];
+                return ref this.GetRowSpan(y)[x];
             }
         }
 
-        /// <summary>
-        /// Gets a <see cref="Span{T}"/> to the row 'y' beginning from the pixel at the first pixel on that row.
-        /// </summary>
-        /// <param name="y">The y (row) coordinate.</param>
-        /// <returns>The <see cref="Span{T}"/>.</returns>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public Span<T> GetRowSpan(int y)
-        {
-            Guard.MustBeGreaterThanOrEqualTo(y, 0, nameof(y));
-            Guard.MustBeLessThan(y, this.Height, nameof(y));
-
-            return this.cachedMemory.Length > 0
-                ? this.cachedMemory.Span.Slice(y * this.Width, this.Width)
-                : this.GetRowMemorySlow(y).Span;
-        }
-
         /// <summary>
         /// Disposes the <see cref="Buffer2D{T}"/> instance
         /// </summary>
@@ -101,10 +88,16 @@ namespace SixLabors.ImageSharp.Memory
         }
 
         /// <summary>
-        /// Same as <see cref="GetRowSpan"/>, but does not validate index in Release mode.
+        /// Gets a <see cref="Span{T}"/> to the row 'y' beginning from the pixel at the first pixel on that row.
         /// </summary>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        /// <remarks>
-        internal Span<T> GetRowSpanUnchecked(int y)
+        /// This method does not validate the y argument for performance reason,
+        /// <see cref="ArgumentOutOfRangeException"/> is being propagated from lower levels.
+        /// </remarks>
+        /// <param name="y">The row index.</param>
+        /// <exception cref="ArgumentOutOfRangeException">Thrown when row index is out of range.</exception>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public Span<T> GetRowSpan(int y)
         {
             DebugGuard.MustBeGreaterThanOrEqualTo(y, 0, nameof(y));
             DebugGuard.MustBeLessThan(y, this.Height, nameof(y));
@@ -114,6 +107,19 @@ namespace SixLabors.ImageSharp.Memory
                 : this.GetRowMemorySlow(y).Span;
         }
 
+        [MethodImpl(InliningOptions.ShortMethod)]
+        internal ref T GetElementUnsafe(int x, int y)
+        {
+            if (this.cachedMemory.Length > 0)
+            {
+                Span<T> span = this.cachedMemory.Span;
+                ref T start = ref MemoryMarshal.GetReference(span);
+                return ref Unsafe.Add(ref start, (y * this.Width) + x);
+            }
+
+            return ref GetElementSlow(x, y);
+        }
+
         /// <summary>
         /// Gets a <see cref="Memory{T}"/> to the row 'y' beginning from the pixel at the first pixel on that row.
         /// This method is intended for internal use only, since it does not use the indirection provided by
@@ -121,8 +127,8 @@ namespace SixLabors.ImageSharp.Memory
         /// </summary>
         /// <param name="y">The y (row) coordinate.</param>
         /// <returns>The <see cref="Span{T}"/>.</returns>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [MethodImpl(InliningOptions.ShortMethod)]
-        internal Memory<T> GetRowMemoryFast(int y)
+        internal Memory<T> GetFastRowMemory(int y)
         {
             DebugGuard.MustBeGreaterThanOrEqualTo(y, 0, nameof(y));
             DebugGuard.MustBeLessThan(y, this.Height, nameof(y));
@@ -136,7 +142,8 @@ namespace SixLabors.ImageSharp.Memory
         /// </summary>
         /// <param name="y">The y (row) coordinate.</param>
         /// <returns>The <see cref="Span{T}"/>.</returns>
-        internal Memory<T> GetRowMemorySafe(int y)
+        [MethodImpl(InliningOptions.ShortMethod)]
+        internal Memory<T> GetSafeRowMemory(int y)
         {
             DebugGuard.MustBeGreaterThanOrEqualTo(y, 0, nameof(y));
             DebugGuard.MustBeLessThan(y, this.Height, nameof(y));
@@ -156,6 +163,13 @@ namespace SixLabors.ImageSharp.Memory
         [MethodImpl(InliningOptions.ColdPath)]
         private Memory<T> GetRowMemorySlow(int y) => this.MemoryGroup.GetBoundedSlice(y * this.Width, this.Width);
 
+        [MethodImpl(InliningOptions.ColdPath)]
+        private ref T GetElementSlow(int x, int y)
+        {
+            Span<T> span = this.GetRowMemorySlow(y).Span;
+            return ref span[x];
+        }
+
         private static void SwapOwnData(Buffer2D<T> a, Buffer2D<T> b, bool swapCachedMemory)
         {
             Size aSize = a.Size();

src/ImageSharp/Processing/Processors/Convolution/BokehBlurProcessor{TPixel}.cs

@@ -364,7 +364,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Convolution
             {
                 for (int y = rows.Min; y < rows.Max; y++)
                 {
-                    Span<ComplexVector4> targetRowSpan = this.targetValues.GetRowSpanUnchecked(y).Slice(this.bounds.X);
+                    Span<ComplexVector4> targetRowSpan = this.targetValues.GetRowSpan(y).Slice(this.bounds.X);
 
                     for (int x = 0; x < this.bounds.Width; x++)
                     {
@@ -413,7 +413,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Convolution
             {
                 for (int y = rows.Min; y < rows.Max; y++)
                 {
-                    Span<Vector4> targetRowSpan = this.targetValues.GetRowSpanUnchecked(y).Slice(this.bounds.X);
+                    Span<Vector4> targetRowSpan = this.targetValues.GetRowSpan(y).Slice(this.bounds.X);
 
                     for (int x = 0; x < this.bounds.Width; x++)
                     {
@@ -452,7 +452,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Convolution
             {
                 for (int y = rows.Min; y < rows.Max; y++)
                 {
-                    Span<TPixel> targetRowSpan = this.targetPixels.GetRowSpanUnchecked(y).Slice(this.bounds.X);
+                    Span<TPixel> targetRowSpan = this.targetPixels.GetRowSpan(y).Slice(this.bounds.X);
                     PixelOperations<TPixel>.Instance.ToVector4(this.configuration, targetRowSpan.Slice(0, span.Length), span, PixelConversionModifiers.Premultiply);
                     ref Vector4 baseRef = ref MemoryMarshal.GetReference(span);
 
@@ -504,8 +504,8 @@ namespace SixLabors.ImageSharp.Processing.Processors.Convolution
 
                 for (int y = rows.Min; y < rows.Max; y++)
                 {
-                    Span<TPixel> targetPixelSpan = this.targetPixels.GetRowSpanUnchecked(y).Slice(this.bounds.X);
+                    Span<TPixel> targetPixelSpan = this.targetPixels.GetRowSpan(y).Slice(this.bounds.X);
-                    Span<Vector4> sourceRowSpan = this.sourceValues.GetRowSpanUnchecked(y).Slice(this.bounds.X);
+                    Span<Vector4> sourceRowSpan = this.sourceValues.GetRowSpan(y).Slice(this.bounds.X);
                     ref Vector4 sourceRef = ref MemoryMarshal.GetReference(sourceRowSpan);
 
                     for (int x = 0; x < this.bounds.Width; x++)

src/ImageSharp/Processing/Processors/Convolution/Convolution2DProcessor{TPixel}.cs

@@ -119,7 +119,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Convolution
 
                 for (int y = rows.Min; y < rows.Max; y++)
                 {
-                    Span<TPixel> targetRowSpan = this.targetPixels.GetRowSpanUnchecked(y).Slice(this.bounds.X);
+                    Span<TPixel> targetRowSpan = this.targetPixels.GetRowSpan(y).Slice(this.bounds.X);
                     PixelOperations<TPixel>.Instance.ToVector4(this.configuration, targetRowSpan.Slice(0, span.Length), span);
 
                     if (this.preserveAlpha)

src/ImageSharp/Processing/Processors/Convolution/Convolution2PassProcessor{TPixel}.cs

@@ -118,7 +118,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Convolution
 
                 for (int y = rows.Min; y < rows.Max; y++)
                 {
-                    Span<TPixel> targetRowSpan = this.targetPixels.GetRowSpanUnchecked(y).Slice(this.bounds.X);
+                    Span<TPixel> targetRowSpan = this.targetPixels.GetRowSpan(y).Slice(this.bounds.X);
                     PixelOperations<TPixel>.Instance.ToVector4(this.configuration, targetRowSpan.Slice(0, span.Length), span);
 
                     if (this.preserveAlpha)

src/ImageSharp/Processing/Processors/Convolution/ConvolutionProcessor{TPixel}.cs

@@ -106,7 +106,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Convolution
 
                 for (int y = rows.Min; y < rows.Max; y++)
                 {
-                    Span<TPixel> targetRowSpan = this.targetPixels.GetRowSpanUnchecked(y).Slice(this.bounds.X);
+                    Span<TPixel> targetRowSpan = this.targetPixels.GetRowSpan(y).Slice(this.bounds.X);
                     PixelOperations<TPixel>.Instance.ToVector4(this.configuration, targetRowSpan.Slice(0, span.Length), span);
 
                     if (this.preserveAlpha)

src/ImageSharp/Processing/Processors/Convolution/EdgeDetectorCompassProcessor{TPixel}.cs

@@ -114,8 +114,8 @@ namespace SixLabors.ImageSharp.Processing.Processors.Convolution
             {
                 for (int y = rows.Min; y < rows.Max; y++)
                 {
-                    ref TPixel passPixelsBase = ref MemoryMarshal.GetReference(this.passPixels.GetRowSpanUnchecked(y));
+                    ref TPixel passPixelsBase = ref MemoryMarshal.GetReference(this.passPixels.GetRowSpan(y));
-                    ref TPixel targetPixelsBase = ref MemoryMarshal.GetReference(this.targetPixels.GetRowSpanUnchecked(y));
+                    ref TPixel targetPixelsBase = ref MemoryMarshal.GetReference(this.targetPixels.GetRowSpan(y));
 
                     for (int x = this.minX; x < this.maxX; x++)
                     {

src/ImageSharp/Processing/Processors/Effects/OilPaintingProcessor{TPixel}.cs

@@ -177,7 +177,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Effects
                         }
                     }
 
-                    Span<TPixel> targetRowAreaPixelSpan = this.targetPixels.GetRowSpanUnchecked(y).Slice(this.bounds.X, this.bounds.Width);
+                    Span<TPixel> targetRowAreaPixelSpan = this.targetPixels.GetRowSpan(y).Slice(this.bounds.X, this.bounds.Width);
 
                     PixelOperations<TPixel>.Instance.FromVector4Destructive(this.configuration, targetRowAreaVector4Span, targetRowAreaPixelSpan);
                 }

src/ImageSharp/Processing/Processors/Normalization/AdaptiveHistogramEqualizationProcessor{TPixel}.cs

@@ -529,7 +529,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
             }
 
             [MethodImpl(InliningOptions.ShortMethod)]
-            public Span<int> GetCdfLutSpan(int tileX, int tileY) => this.cdfLutBuffer2D.GetRowSpanUnchecked(tileY).Slice(tileX * this.luminanceLevels, this.luminanceLevels);
+            public Span<int> GetCdfLutSpan(int tileX, int tileY) => this.cdfLutBuffer2D.GetRowSpan(tileY).Slice(tileX * this.luminanceLevels, this.luminanceLevels);
 
             /// <summary>
             /// Remaps the grey value with the cdf.
@@ -605,7 +605,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
                         int cdfY = this.tileYStartPositions[index].cdfY;
                         int y = this.tileYStartPositions[index].y;
                         int endY = Math.Min(y + this.tileHeight, this.sourceHeight);
-                        ref int cdfMinBase = ref MemoryMarshal.GetReference(this.cdfMinBuffer2D.GetRowSpanUnchecked(cdfY));
+                        ref int cdfMinBase = ref MemoryMarshal.GetReference(this.cdfMinBuffer2D.GetRowSpan(cdfY));
 
                         using IMemoryOwner<int> histogramBuffer = this.allocator.Allocate<int>(this.luminanceLevels);
                         Span<int> histogram = histogramBuffer.GetSpan();
@@ -614,7 +614,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
                         for (int x = 0; x < this.sourceWidth; x += this.tileWidth)
                         {
                             histogram.Clear();
-                            Span<int> cdfLutSpan = this.cdfLutBuffer2D.GetRowSpanUnchecked(index).Slice(cdfX * this.luminanceLevels, this.luminanceLevels);
+                            Span<int> cdfLutSpan = this.cdfLutBuffer2D.GetRowSpan(index).Slice(cdfX * this.luminanceLevels, this.luminanceLevels);
                             ref int cdfBase = ref MemoryMarshal.GetReference(cdfLutSpan);
 
                             int xlimit = Math.Min(x + this.tileWidth, this.sourceWidth);

src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeKernelMap.cs

@@ -241,7 +241,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
                     $"Error in KernelMap.CreateKernel({dataRowIndex},{left},{right}): left > this.data.Width");
             }
 
-            Span<float> rowSpan = this.data.GetRowSpanUnchecked(dataRowIndex);
+            Span<float> rowSpan = this.data.GetRowSpan(dataRowIndex);
 
             ref float rowReference = ref MemoryMarshal.GetReference(rowSpan);
             float* rowPtr = (float*)Unsafe.AsPointer(ref rowReference);

src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeWorker.cs

@@ -102,7 +102,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public Span<Vector4> GetColumnSpan(int x, int startY)
         {
-            return this.transposedFirstPassBuffer.GetRowSpanUnchecked(x).Slice(startY - this.currentWindow.Min);
+            return this.transposedFirstPassBuffer.GetRowSpan(x).Slice(startY - this.currentWindow.Min);
         }
 
         public void Initialize()
@@ -138,7 +138,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
                     Unsafe.Add(ref tempRowBase, x) = kernel.ConvolveCore(ref firstPassColumnBase);
                 }
 
-                Span<TPixel> targetRowSpan = destination.GetRowSpanUnchecked(y);
+                Span<TPixel> targetRowSpan = destination.GetRowSpan(y);
 
                 PixelOperations<TPixel>.Instance.FromVector4Destructive(this.configuration, tempColSpan, targetRowSpan, this.conversionModifiers);
             }

src/ImageSharp/Processing/Processors/Transforms/TransformKernelMap.cs

@@ -53,7 +53,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         /// <returns>The reference to the first item of the window.</returns>
         [MethodImpl(InliningOptions.ShortMethod)]
         public ref float GetYStartReference(int y)
-            => ref MemoryMarshal.GetReference(this.yBuffer.GetRowSpanUnchecked(y));
+            => ref MemoryMarshal.GetReference(this.yBuffer.GetRowSpan(y));
 
         /// <summary>
         /// Gets a reference to the first item of the x window.
@@ -61,7 +61,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         /// <returns>The reference to the first item of the window.</returns>
         [MethodImpl(InliningOptions.ShortMethod)]
         public ref float GetXStartReference(int y)
-            => ref MemoryMarshal.GetReference(this.xBuffer.GetRowSpanUnchecked(y));
+            => ref MemoryMarshal.GetReference(this.xBuffer.GetRowSpan(y));
 
         public void Convolve<TPixel>(
             Vector2 transformedPoint,

tests/ImageSharp.Benchmarks/PixelBlenders/PorterDuffBulkVsPixel.cs

@@ -78,7 +78,7 @@ namespace SixLabors.ImageSharp.Benchmarks
                     Buffer2D<Rgba32> pixels = image.GetRootFramePixelBuffer();
                     for (int y = 0; y < image.Height; y++)
                     {
-                        Span<Rgba32> span = pixels.GetRowSpanUnchecked(y);
+                        Span<Rgba32> span = pixels.GetRowSpan(y);
                         this.BulkVectorConvert(span, span, span, amounts.GetSpan());
                     }
 
@@ -98,7 +98,7 @@ namespace SixLabors.ImageSharp.Benchmarks
                     Buffer2D<Rgba32> pixels = image.GetRootFramePixelBuffer();
                     for (int y = 0; y < image.Height; y++)
                     {
-                        Span<Rgba32> span = pixels.GetRowSpanUnchecked(y);
+                        Span<Rgba32> span = pixels.GetRowSpan(y);
                         this.BulkPixelConvert(span, span, span, amounts.GetSpan());
                     }
 

tests/ImageSharp.Tests/Formats/Jpg/Utils/LibJpegTools.ComponentData.cs

@@ -65,7 +65,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg.Utils
 
                 for (int y = 0; y < result.HeightInBlocks; y++)
                 {
-                    Span<Block8x8> blockRow = c.SpectralBlocks.GetRowSpanUnchecked(y);
+                    Span<Block8x8> blockRow = c.SpectralBlocks.GetRowSpan(y);
                     for (int x = 0; x < result.WidthInBlocks; x++)
                     {
                         short[] data = blockRow[x].ToArray();

tests/ImageSharp.Tests/Image/ImageFrameTests.cs

@@ -0,0 +1,96 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Tests
+{
+    public class ImageFrameTests
+    {
+        public class Indexer
+        {
+            private readonly Configuration configuration = Configuration.CreateDefaultInstance();
+
+            private void LimitBufferCapacity(int bufferCapacityInBytes)
+            {
+                var allocator = (ArrayPoolMemoryAllocator)this.configuration.MemoryAllocator;
+                allocator.BufferCapacityInBytes = bufferCapacityInBytes;
+            }
+
+            [Theory]
+            [InlineData(false)]
+            [InlineData(true)]
+            public void GetSet(bool enforceDisco)
+            {
+                if (enforceDisco)
+                {
+                    this.LimitBufferCapacity(100);
+                }
+
+                using var image = new Image<Rgba32>(this.configuration, 10, 10);
+                ImageFrame<Rgba32> frame = image.Frames.RootFrame;
+                Rgba32 val = frame[3, 4];
+                Assert.Equal(default(Rgba32), val);
+                frame[3, 4] = Color.Red;
+                val = frame[3, 4];
+                Assert.Equal(Color.Red.ToRgba32(), val);
+            }
+
+            public static TheoryData<bool, int> OutOfRangeData = new TheoryData<bool, int>()
+            {
+                { false, -1 },
+                { false, 10 },
+                { true, -1 },
+                { true, 10 },
+            };
+
+            [Theory]
+            [MemberData(nameof(OutOfRangeData))]
+            public void Get_OutOfRangeX(bool enforceDisco, int x)
+            {
+                if (enforceDisco)
+                {
+                    this.LimitBufferCapacity(100);
+                }
+
+                using var image = new Image<Rgba32>(this.configuration, 10, 10);
+                ImageFrame<Rgba32> frame = image.Frames.RootFrame;
+                ArgumentOutOfRangeException ex = Assert.Throws<ArgumentOutOfRangeException>(() => _ = frame[x, 3]);
+                Assert.Equal("x", ex.ParamName);
+            }
+
+            [Theory]
+            [MemberData(nameof(OutOfRangeData))]
+            public void Set_OutOfRangeX(bool enforceDisco, int x)
+            {
+                if (enforceDisco)
+                {
+                    this.LimitBufferCapacity(100);
+                }
+
+                using var image = new Image<Rgba32>(this.configuration, 10, 10);
+                ImageFrame<Rgba32> frame = image.Frames.RootFrame;
+                ArgumentOutOfRangeException ex = Assert.Throws<ArgumentOutOfRangeException>(() => frame[x, 3] = default);
+                Assert.Equal("x", ex.ParamName);
+            }
+
+            [Theory]
+            [MemberData(nameof(OutOfRangeData))]
+            public void Set_OutOfRangeY(bool enforceDisco, int y)
+            {
+                if (enforceDisco)
+                {
+                    this.LimitBufferCapacity(100);
+                }
+
+                using var image = new Image<Rgba32>(this.configuration, 10, 10);
+                ImageFrame<Rgba32> frame = image.Frames.RootFrame;
+                ArgumentOutOfRangeException ex = Assert.Throws<ArgumentOutOfRangeException>(() => frame[3, y] = default);
+                Assert.Equal("y", ex.ParamName);
+            }
+        }
+    }
+}

tests/ImageSharp.Tests/Image/ImageTests.cs

@@ -1,7 +1,9 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
+using System;
 using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.ImageSharp.Tests.Memory;
@@ -85,5 +87,84 @@ namespace SixLabors.ImageSharp.Tests
                 }
             }
         }
+
+        public class Indexer
+        {
+            private readonly Configuration configuration = Configuration.CreateDefaultInstance();
+
+            private void LimitBufferCapacity(int bufferCapacityInBytes)
+            {
+                var allocator = (ArrayPoolMemoryAllocator)this.configuration.MemoryAllocator;
+                allocator.BufferCapacityInBytes = bufferCapacityInBytes;
+            }
+
+            [Theory]
+            [InlineData(false)]
+            [InlineData(true)]
+            public void GetSet(bool enforceDisco)
+            {
+                if (enforceDisco)
+                {
+                    this.LimitBufferCapacity(100);
+                }
+
+                using var image = new Image<Rgba32>(this.configuration, 10, 10);
+                Rgba32 val = image[3, 4];
+                Assert.Equal(default(Rgba32), val);
+                image[3, 4] = Color.Red;
+                val = image[3, 4];
+                Assert.Equal(Color.Red.ToRgba32(), val);
+            }
+
+            public static TheoryData<bool, int> OutOfRangeData = new TheoryData<bool, int>()
+            {
+                { false, -1 },
+                { false, 10 },
+                { true, -1 },
+                { true, 10 },
+            };
+
+            [Theory]
+            [MemberData(nameof(OutOfRangeData))]
+            public void Get_OutOfRangeX(bool enforceDisco, int x)
+            {
+                if (enforceDisco)
+                {
+                    this.LimitBufferCapacity(100);
+                }
+
+                using var image = new Image<Rgba32>(this.configuration, 10, 10);
+                ArgumentOutOfRangeException ex = Assert.Throws<ArgumentOutOfRangeException>(() => _ = image[x, 3]);
+                Assert.Equal("x", ex.ParamName);
+            }
+
+            [Theory]
+            [MemberData(nameof(OutOfRangeData))]
+            public void Set_OutOfRangeX(bool enforceDisco, int x)
+            {
+                if (enforceDisco)
+                {
+                    this.LimitBufferCapacity(100);
+                }
+
+                using var image = new Image<Rgba32>(this.configuration, 10, 10);
+                ArgumentOutOfRangeException ex = Assert.Throws<ArgumentOutOfRangeException>(() => image[x, 3] = default);
+                Assert.Equal("x", ex.ParamName);
+            }
+
+            [Theory]
+            [MemberData(nameof(OutOfRangeData))]
+            public void Set_OutOfRangeY(bool enforceDisco, int y)
+            {
+                if (enforceDisco)
+                {
+                    this.LimitBufferCapacity(100);
+                }
+
+                using var image = new Image<Rgba32>(this.configuration, 10, 10);
+                ArgumentOutOfRangeException ex = Assert.Throws<ArgumentOutOfRangeException>(() => image[3, y] = default);
+                Assert.Equal("y", ex.ParamName);
+            }
+        }
     }
 }

tests/ImageSharp.Tests/Memory/Buffer2DTests.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Buffers;
+using System.Diagnostics;
 using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
@@ -95,7 +96,7 @@ namespace SixLabors.ImageSharp.Tests.Memory
 
             using (Buffer2D<TestStructs.Foo> buffer = this.MemoryAllocator.Allocate2D<TestStructs.Foo>(width, height))
             {
-                Span<TestStructs.Foo> span = buffer.GetRowSpanUnchecked(y);
+                Span<TestStructs.Foo> span = buffer.GetRowSpan(y);
 
                 Assert.Equal(width, span.Length);
 
@@ -104,6 +105,48 @@ namespace SixLabors.ImageSharp.Tests.Memory
             }
         }
 
+        public static TheoryData<int, int, int, int> GetRowSpanY_OutOfRange_Data = new TheoryData<int, int, int, int>()
+        {
+            { Big, 10, 8, -1 },
+            { Big, 10, 8, 8 },
+            { 20, 10, 8, -1 },
+            { 20, 10, 8, 10 },
+        };
+
+        [Theory]
+        [MemberData(nameof(GetRowSpanY_OutOfRange_Data))]
+        public void GetRowSpan_OutOfRange(int bufferCapacity, int width, int height, int y)
+        {
+            this.MemoryAllocator.BufferCapacityInBytes = bufferCapacity;
+            using Buffer2D<byte> buffer = this.MemoryAllocator.Allocate2D<byte>(width, height);
+
+            Exception ex = Assert.ThrowsAny<Exception>(() => buffer.GetRowSpan(y));
+            Assert.True(ex is ArgumentOutOfRangeException || ex is IndexOutOfRangeException);
+        }
+
+        public static TheoryData<int, int, int, int, int> Indexer_OutOfRange_Data = new TheoryData<int, int, int, int, int>()
+        {
+            { Big, 10, 8, 1, -1 },
+            { Big, 10, 8, 1, 8 },
+            { Big, 10, 8, -1, 1 },
+            { Big, 10, 8, 10, 1 },
+            { 20, 10, 8, 1, -1 },
+            { 20, 10, 8, 1, 10 },
+            { 20, 10, 8, -1, 1 },
+            { 20, 10, 8, 10, 1 },
+        };
+
+        [Theory]
+        [MemberData(nameof(Indexer_OutOfRange_Data))]
+        public void Indexer_OutOfRange(int bufferCapacity, int width, int height, int x, int y)
+        {
+            this.MemoryAllocator.BufferCapacityInBytes = bufferCapacity;
+            using Buffer2D<byte> buffer = this.MemoryAllocator.Allocate2D<byte>(width, height);
+
+            Exception ex = Assert.ThrowsAny<Exception>(() => buffer[x, y]++);
+            Assert.True(ex is ArgumentOutOfRangeException || ex is IndexOutOfRangeException);
+        }
+
         [Theory]
         [InlineData(Big, 42, 8, 0, 0)]
         [InlineData(Big, 400, 1000, 20, 10)]
@@ -168,10 +211,10 @@ namespace SixLabors.ImageSharp.Tests.Memory
                 Buffer2D<int>.SwapOrCopyContent(dest, source);
             }
 
-            int actual1 = dest.GetRowSpanUnchecked(0)[0];
+            int actual1 = dest.GetRowSpan(0)[0];
             int actual2 = dest.GetRowSpan(0)[0];
-            int actual3 = dest.GetRowMemorySafe(0).Span[0];
+            int actual3 = dest.GetSafeRowMemory(0).Span[0];
-            int actual4 = dest.GetRowMemoryFast(0).Span[0];
+            int actual4 = dest.GetFastRowMemory(0).Span[0];
             int actual5 = dest[0, 0];
 
             Assert.Equal(1, actual1);
@@ -199,7 +242,7 @@ namespace SixLabors.ImageSharp.Tests.Memory
 
                 for (int y = 0; y < b.Height; y++)
                 {
-                    Span<float> row = b.GetRowSpanUnchecked(y);
+                    Span<float> row = b.GetRowSpan(y);
 
                     Span<float> s = row.Slice(startIndex, columnCount);
                     Span<float> d = row.Slice(destIndex, columnCount);
@@ -222,7 +265,7 @@ namespace SixLabors.ImageSharp.Tests.Memory
 
                 for (int y = 0; y < b.Height; y++)
                 {
-                    Span<float> row = b.GetRowSpanUnchecked(y);
+                    Span<float> row = b.GetRowSpan(y);
 
                     Span<float> s = row.Slice(0, 22);
                     Span<float> d = row.Slice(50, 22);

tests/ImageSharp.Tests/Memory/BufferAreaTests.cs

@@ -127,7 +127,7 @@ namespace SixLabors.ImageSharp.Tests.Memory
 
             for (int y = 0; y < 13; y++)
             {
-                Span<int> row = buffer.GetRowSpanUnchecked(y);
+                Span<int> row = buffer.GetRowSpan(y);
                 Assert.True(row.SequenceEqual(emptyRow));
             }
         }
@@ -151,7 +151,7 @@ namespace SixLabors.ImageSharp.Tests.Memory
 
             for (int y = area.Rectangle.Y; y < area.Rectangle.Bottom; y++)
             {
-                Span<int> span = buffer.GetRowSpanUnchecked(y).Slice(area.Rectangle.X, area.Width);
+                Span<int> span = buffer.GetRowSpan(y).Slice(area.Rectangle.X, area.Width);
                 Assert.True(span.SequenceEqual(new int[area.Width]));
             }
         }