Merge pull request #591 from brianpopow/feature/fix-576

Fix for #576, using explicit struct layout for bgr24 and rgb24

src/ImageSharp/PixelFormats/Bgr24.cs

@@ -14,22 +14,25 @@ namespace SixLabors.ImageSharp.PixelFormats
     /// Ranges from [0, 0, 0, 1] to [1, 1, 1, 1] in vector form.
     /// </para>
     /// </summary>
-    [StructLayout(LayoutKind.Sequential)]
+    [StructLayout(LayoutKind.Explicit)]
     public struct Bgr24 : IPixel<Bgr24>
     {
         /// <summary>
         /// The blue component.
         /// </summary>
+        [FieldOffset(0)]
         public byte B;
 
         /// <summary>
         /// The green component.
         /// </summary>
+        [FieldOffset(1)]
         public byte G;
 
         /// <summary>
         /// The red component.
         /// </summary>
+        [FieldOffset(2)]
         public byte R;
 
         /// <summary>

src/ImageSharp/PixelFormats/Rgb24.cs

@@ -15,22 +15,25 @@ namespace SixLabors.ImageSharp.PixelFormats
     /// Ranges from [0, 0, 0, 1] to [1, 1, 1, 1] in vector form.
     /// </para>
     /// </summary>
-    [StructLayout(LayoutKind.Sequential)]
+    [StructLayout(LayoutKind.Explicit)]
     public struct Rgb24 : IPixel<Rgb24>
     {
         /// <summary>
         /// The red component.
         /// </summary>
+        [FieldOffset(0)]
         public byte R;
 
         /// <summary>
         /// The green component.
         /// </summary>
+        [FieldOffset(1)]
         public byte G;
 
         /// <summary>
         /// The blue component.
         /// </summary>
+        [FieldOffset(2)]
         public byte B;
 
         /// <summary>

tests/ImageSharp.Tests/Image/ImageCloneTests.cs

@@ -33,10 +33,7 @@ namespace SixLabors.ImageSharp.Tests
             }
         }
 
-        /// <summary>
-        /// https://github.com/SixLabors/ImageSharp/issues/576
-        /// </summary>
-        [Theory(Skip = "See https://github.com/SixLabors/ImageSharp/issues/576")]
+        [Theory]
         [WithTestPatternImages(9, 9, PixelTypes.Rgba32)]
         public void CloneAs_ToBgr24(TestImageProvider<Rgba32> provider)
         {