Update source generators to use ReadOnlySpan

src/ImageSharp/PixelFormats/Generated/PixelOperations{TPixel}.Generated.cs

@@ -35,7 +35,7 @@ namespace SixLabors.ImageSharp.PixelFormats
         }
 
         /// <summary>
-        /// A helper for <see cref="PackFromRgba32(Span{Rgba32}, Span{TPixel}, int)"/> that expects a byte span.
+        /// A helper for <see cref="PackFromRgba32(ReadOnlySpan{byte}, Span{TPixel}, int)"/> that expects a byte span.
         /// The layout of the data in 'sourceBytes' must be compatible with <see cref="Rgba32"/> layout.
         /// </summary>
         /// <param name="sourceBytes">The <see cref="Span{T}"/> to the source bytes.</param>
@@ -70,7 +70,7 @@ namespace SixLabors.ImageSharp.PixelFormats
         }
 
         /// <summary>
-        /// A helper for <see cref="ToRgba32(Span{TPixel}, Span{Rgba32}, int)"/> that expects a byte span as destination.
+        /// A helper for <see cref="ToRgba32(ReadOnlySpan{TPixel}, Span{Rgba32}, int)"/> that expects a byte span as destination.
         /// The layout of the data in 'destBytes' must be compatible with <see cref="Rgba32"/> layout.
         /// </summary>
         /// <param name="sourceColors">The <see cref="Span{T}"/> to the source colors.</param>
@@ -106,7 +106,7 @@ namespace SixLabors.ImageSharp.PixelFormats
         }
 
         /// <summary>
-        /// A helper for <see cref="PackFromBgra32(Span{Bgra32}, Span{TPixel}, int)"/> that expects a byte span.
+        /// A helper for <see cref="PackFromBgra32(ReadOnlySpan{Bgra32}, Span{TPixel}, int)"/> that expects a byte span.
         /// The layout of the data in 'sourceBytes' must be compatible with <see cref="Bgra32"/> layout.
         /// </summary>
         /// <param name="sourceBytes">The <see cref="Span{T}"/> to the source bytes.</param>
@@ -141,7 +141,7 @@ namespace SixLabors.ImageSharp.PixelFormats
         }
 
         /// <summary>
-        /// A helper for <see cref="ToBgra32(Span{TPixel}, Span{Bgra32}, int)"/> that expects a byte span as destination.
+        /// A helper for <see cref="ToBgra32(ReadOnlySpan{TPixel}, Span{Bgra32}, int)"/> that expects a byte span as destination.
         /// The layout of the data in 'destBytes' must be compatible with <see cref="Bgra32"/> layout.
         /// </summary>
         /// <param name="sourceColors">The <see cref="Span{T}"/> to the source colors.</param>
@@ -177,7 +177,7 @@ namespace SixLabors.ImageSharp.PixelFormats
         }
 
         /// <summary>
-        /// A helper for <see cref="PackFromRgb24(Span{Rgb24}, Span{TPixel}, int)"/> that expects a byte span.
+        /// A helper for <see cref="PackFromRgb24(ReadOnlySpan{Rgb24}, Span{TPixel}, int)"/> that expects a byte span.
         /// The layout of the data in 'sourceBytes' must be compatible with <see cref="Rgb24"/> layout.
         /// </summary>
         /// <param name="sourceBytes">The <see cref="Span{T}"/> to the source bytes.</param>
@@ -212,7 +212,7 @@ namespace SixLabors.ImageSharp.PixelFormats
         }
 
         /// <summary>
-        /// A helper for <see cref="ToRgb24(Span{TPixel}, Span{Rgb24}, int)"/> that expects a byte span as destination.
+        /// A helper for <see cref="ToRgb24(ReadOnlySpan{TPixel}, Span{Rgb24}, int)"/> that expects a byte span as destination.
         /// The layout of the data in 'destBytes' must be compatible with <see cref="Rgb24"/> layout.
         /// </summary>
         /// <param name="sourceColors">The <see cref="Span{T}"/> to the source colors.</param>
@@ -283,7 +283,7 @@ namespace SixLabors.ImageSharp.PixelFormats
         }
 
         /// <summary>
-        /// A helper for <see cref="ToBgr24(Span{TPixel}, Span{Bgr24}, int)"/> that expects a byte span as destination.
+        /// A helper for <see cref="ToBgr24(ReadOnlySpan{TPixel}, Span{Bgr24}, int)"/> that expects a byte span as destination.
         /// The layout of the data in 'destBytes' must be compatible with <see cref="Bgr24"/> layout.
         /// </summary>
         /// <param name="sourceColors">The <see cref="Span{T}"/> to the source colors.</param>

src/ImageSharp/PixelFormats/Generated/Rgba32.PixelOperations.Generated.tt

@@ -14,7 +14,7 @@
         #>
 
 			/// <inheritdoc />
-            internal override void PackFrom<#=pixelType#>(Span<<#=pixelType#>> source, Span<Rgba32> destPixels, int count)
+            internal override void PackFrom<#=pixelType#>(ReadOnlySpan<<#=pixelType#>> source, Span<Rgba32> destPixels, int count)
             {
                 GuardSpans(source, nameof(source), destPixels, nameof(destPixels), count);
 
@@ -36,7 +36,7 @@
         #>
 
 			/// <inheritdoc />
-            internal override void To<#=pixelType#>(Span<Rgba32> sourcePixels, Span<<#=pixelType#>> dest, int count)
+            internal override void To<#=pixelType#>(ReadOnlySpan<Rgba32> sourcePixels, Span<<#=pixelType#>> dest, int count)
             {
                 GuardSpans(sourcePixels, nameof(sourcePixels), dest, nameof(dest), count);