source should be ReadOnlySpan<T> for all bulk-conversion methods + increase tolerance because of failing test case

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieLab.cs

@@ -38,7 +38,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -71,7 +71,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -104,7 +104,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -137,7 +137,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -172,7 +172,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -204,7 +204,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -237,7 +237,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -269,7 +269,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -302,7 +302,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -335,7 +335,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -368,7 +368,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -401,7 +401,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -434,7 +434,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<CieLab> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<CieLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieLch.cs

@@ -38,7 +38,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -71,7 +71,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -104,7 +104,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -137,7 +137,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -170,7 +170,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -202,7 +202,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -235,7 +235,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -268,7 +268,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -301,7 +301,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -334,7 +334,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -367,7 +367,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -400,7 +400,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -433,7 +433,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<CieLch> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<CieLch> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieLchuv.cs

@@ -36,7 +36,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -69,7 +69,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -104,7 +104,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -137,7 +137,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -170,7 +170,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -203,7 +203,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -236,7 +236,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -269,7 +269,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -302,7 +302,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -335,7 +335,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -368,7 +368,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -401,7 +401,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -433,7 +433,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<CieLchuv> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<CieLchuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieLuv.cs

@@ -32,7 +32,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -64,7 +64,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -99,7 +99,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -131,7 +131,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -166,7 +166,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -198,7 +198,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -230,7 +230,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -262,7 +262,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -294,7 +294,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -326,7 +326,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -358,7 +358,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -390,7 +390,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -422,7 +422,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<CieLuv> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<CieLuv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieXyy.cs

@@ -33,7 +33,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -66,7 +66,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -99,7 +99,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -132,7 +132,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -160,7 +160,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -193,7 +193,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -226,7 +226,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -259,7 +259,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -292,7 +292,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -325,7 +325,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -358,7 +358,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -391,7 +391,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -424,7 +424,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<CieXyy> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<CieXyy> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieXyz.cs

@@ -41,7 +41,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -76,7 +76,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -111,7 +111,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -146,7 +146,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -178,7 +178,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -212,7 +212,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -246,7 +246,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -280,7 +280,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -315,7 +315,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -351,7 +351,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -383,7 +383,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -416,7 +416,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -450,7 +450,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<CieXyz> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<CieXyz> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.Cmyk.cs

@@ -33,7 +33,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -66,7 +66,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -99,7 +99,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -132,7 +132,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -165,7 +165,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -198,7 +198,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -231,7 +231,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -264,7 +264,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -297,7 +297,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -330,7 +330,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -363,7 +363,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -391,7 +391,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -424,7 +424,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<Cmyk> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<Cmyk> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.Hsl.cs

@@ -33,7 +33,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -66,7 +66,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -99,7 +99,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -132,7 +132,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -165,7 +165,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -198,7 +198,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -231,7 +231,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -264,7 +264,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -297,7 +297,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -330,7 +330,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -363,7 +363,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -391,7 +391,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -424,7 +424,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<Hsl> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<Hsl> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.Hsv.cs

@@ -33,7 +33,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -66,7 +66,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -99,7 +99,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -132,7 +132,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -165,7 +165,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -198,7 +198,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -231,7 +231,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -264,7 +264,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -297,7 +297,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -330,7 +330,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -363,7 +363,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -391,7 +391,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -424,7 +424,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<Hsv> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<Hsv> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.HunterLab.cs

@@ -29,7 +29,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -61,7 +61,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -93,7 +93,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -125,7 +125,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -157,7 +157,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -192,7 +192,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -224,7 +224,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -256,7 +256,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -288,7 +288,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -320,7 +320,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -352,7 +352,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -384,7 +384,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -416,7 +416,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<HunterLab> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<HunterLab> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.LinearRgb.cs

@@ -32,7 +32,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -64,7 +64,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -96,7 +96,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -128,7 +128,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -160,7 +160,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -195,7 +195,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -227,7 +227,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -259,7 +259,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -291,7 +291,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -323,7 +323,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -355,7 +355,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -387,7 +387,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -419,7 +419,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<LinearRgb> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<LinearRgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.Lms.cs

@@ -29,7 +29,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -61,7 +61,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -93,7 +93,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -125,7 +125,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -157,7 +157,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -185,7 +185,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -217,7 +217,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -249,7 +249,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -281,7 +281,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -313,7 +313,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -345,7 +345,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -377,7 +377,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -409,7 +409,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<Lms> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<Lms> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.Rgb.cs

@@ -32,7 +32,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -64,7 +64,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -96,7 +96,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLchuv> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieLchuv> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -128,7 +128,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -160,7 +160,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -195,7 +195,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -227,7 +227,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -259,7 +259,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -291,7 +291,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -323,7 +323,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -355,7 +355,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -387,7 +387,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -422,7 +422,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<YCbCr> source, Span<Rgb> destination, int count)
+        public void Convert(ReadOnlySpan<YCbCr> source, Span<Rgb> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.YCbCr.cs

@@ -33,7 +33,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLab> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<CieLab> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -66,7 +66,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLch> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<CieLch> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -99,7 +99,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieLuv> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<CieLuv> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -132,7 +132,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyy> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyy> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -165,7 +165,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<CieXyz> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<CieXyz> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -198,7 +198,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Cmyk> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<Cmyk> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -231,7 +231,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsl> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<Hsl> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -264,7 +264,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Hsv> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<Hsv> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -297,7 +297,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<HunterLab> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<HunterLab> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -330,7 +330,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<LinearRgb> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<LinearRgb> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -363,7 +363,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Lms> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<Lms> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 
@@ -391,7 +391,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="source">The span to the source colors</param>
         /// <param name="destination">The span to the destination colors</param>
         /// <param name="count">The number of colors to convert.</param>
-        public void Convert(Span<Rgb> source, Span<YCbCr> destination, int count)
+        public void Convert(ReadOnlySpan<Rgb> source, Span<YCbCr> destination, int count)
         {
             Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
 

src/ImageSharp/Common/Helpers/Guard.cs

@@ -264,5 +264,27 @@ namespace SixLabors.ImageSharp
             MustBeSizedAtLeast(source, minLength, sourceParamName);
             MustBeSizedAtLeast(dest, minLength, destParamName);
         }
+
+        /// <summary>
+        /// Verifies that the given 'source' and 'dest' spans are at least of 'minLength' size.
+        /// Throwing an <see cref="ArgumentException"/> if the condition is not met.
+        /// </summary>
+        /// <typeparam name="TSource">The source element type</typeparam>
+        /// <typeparam name="TDest">The destination element type</typeparam>
+        /// <param name="source">The source span</param>
+        /// <param name="sourceParamName">The source parameter name</param>
+        /// <param name="dest">The destination span</param>
+        /// <param name="destParamName">The destination parameter name</param>
+        /// <param name="minLength">The minimum length</param>
+        public static void SpansMustBeSizedAtLeast<TSource, TDest>(
+            ReadOnlySpan<TSource> source,
+            string sourceParamName,
+            Span<TDest> dest,
+            string destParamName,
+            int minLength)
+        {
+            MustBeSizedAtLeast(source, minLength, sourceParamName);
+            MustBeSizedAtLeast(dest, minLength, destParamName);
+        }
     }
 }

tests/ImageSharp.Tests/Colorspaces/Conversion/CieLabAndCieLchuvConversionTests.cs

@@ -17,7 +17,7 @@ namespace SixLabors.ImageSharp.Tests.Colorspaces.Conversion
     /// </remarks>
     public class CieLabAndCieLchuvConversionTests
     {
-        private static readonly ApproximateColorSpaceComparer ColorSpaceComparer = new ApproximateColorSpaceComparer(.0001F);
+        private static readonly ApproximateColorSpaceComparer ColorSpaceComparer = new ApproximateColorSpaceComparer(.0002F);
         private static readonly ColorSpaceConverter Converter = new ColorSpaceConverter();
 
         /// <summary>
@@ -68,7 +68,6 @@ namespace SixLabors.ImageSharp.Tests.Colorspaces.Conversion
         [InlineData(9.953703, -35.1176033, 16.8696461, 9.953705, 25.3788586, 141.070892)]
         [InlineData(9.805839, 55.69225, -36.6074753, 9.80584049, 35.3214073, 314.4875)]
         [InlineData(8.86916, -34.4068336, -42.2136269, 8.869162, 32.1432457, 227.960419)]
-
         public void Convert_Lab_to_Lchuv(float l, float a, float b, float l2, float c, float h)
         {
             // Arrange