Cleanup ByteExtensions

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]);
+        }     
     }
 }

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);
                     }

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;