Merge pull request #10783 from AvaloniaUI/feature/rgb24

Added Rgb24 and Bgr24

src/Avalonia.Base/Media/Imaging/PixelFormatReaders.cs

@@ -228,6 +228,44 @@ static unsafe class PixelFormatReader
 
         public void Reset(IntPtr address) => _address = (Rgba64*)address;
     }
+    
+    public unsafe struct Rgb24PixelFormatReader : IPixelFormatReader
+    {
+        private byte* _address;
+        public Rgba8888Pixel ReadNext()
+        {
+            var addr = _address;
+            _address += 3;
+            return new Rgba8888Pixel
+            {
+                R = addr[0],
+                G = addr[1],
+                B = addr[2],
+                A = 255,
+            };
+        }
+
+        public void Reset(IntPtr address) => _address = (byte*)address;
+    }
+    
+    public unsafe struct Bgr24PixelFormatReader : IPixelFormatReader
+    {
+        private byte* _address;
+        public Rgba8888Pixel ReadNext()
+        {
+            var addr = _address;
+            _address += 3;
+            return new Rgba8888Pixel
+            {
+                R = addr[2],
+                G = addr[1],
+                B = addr[0],
+                A = 255,
+            };
+        }
+
+        public void Reset(IntPtr address) => _address = (byte*)address;
+    }
 
     public static void Transcode(IntPtr dst, IntPtr src, PixelSize size, int strideSrc, int strideDst,
         PixelFormat format)
@@ -242,6 +280,10 @@ static unsafe class PixelFormatReader
             Transcode<Gray8PixelReader>(dst, src, size, strideSrc, strideDst);
         else if (format == PixelFormats.Gray16)
             Transcode<Gray16PixelReader>(dst, src, size, strideSrc, strideDst);
+        else if (format == PixelFormats.Rgb24)
+            Transcode<Rgb24PixelFormatReader>(dst, src, size, strideSrc, strideDst);
+        else if (format == PixelFormats.Bgr24)
+            Transcode<Bgr24PixelFormatReader>(dst, src, size, strideSrc, strideDst);
         else if (format == PixelFormats.Gray32Float)
             Transcode<Gray32FloatPixelReader>(dst, src, size, strideSrc, strideDst);
         else if (format == PixelFormats.Rgba64)
@@ -258,7 +300,9 @@ static unsafe class PixelFormatReader
                || format == PixelFormats.Gray8
                || format == PixelFormats.Gray16
                || format == PixelFormats.Gray32Float
-               || format == PixelFormats.Rgba64;
+               || format == PixelFormats.Rgba64
+               || format == PixelFormats.Bgr24
+               || format == PixelFormats.Rgb24;
     }
     
     public static void Transcode<TReader>(IntPtr dst, IntPtr src, PixelSize size, int strideSrc, int strideDst) where TReader : struct, IPixelFormatReader

src/Avalonia.Base/Platform/PixelFormat.cs

@@ -13,7 +13,9 @@ namespace Avalonia.Platform
         Gray8,
         Gray16,
         Gray32Float,
-        Rgba64
+        Rgba64,
+        Rgb24,
+        Bgr24
     }
 
     public record struct PixelFormat
@@ -35,6 +37,8 @@ namespace Avalonia.Platform
                 else if (FormatEnum == PixelFormatEnum.Rgb565 
                          || FormatEnum == PixelFormatEnum.Gray16)
                     return 16;
+                else if (FormatEnum is PixelFormatEnum.Bgr24 or PixelFormatEnum.Rgb24)
+                    return 24;
                 else if (FormatEnum == PixelFormatEnum.Rgba64)
                     return 64;
 
@@ -70,5 +74,7 @@ namespace Avalonia.Platform
         public static PixelFormat Gray8 { get; } = new PixelFormat(PixelFormatEnum.Gray8);
         public static PixelFormat Gray16 { get; } = new PixelFormat(PixelFormatEnum.Gray16);
         public static PixelFormat Gray32Float { get; } = new PixelFormat(PixelFormatEnum.Gray32Float);
+        public static PixelFormat Rgb24 { get; } = new PixelFormat(PixelFormatEnum.Rgb24);
+        public static PixelFormat Bgr24 { get; } = new PixelFormat(PixelFormatEnum.Bgr24);
     }
 }

tests/Avalonia.RenderTests/Media/BitmapTests.cs

@@ -143,6 +143,8 @@ namespace Avalonia.Direct2D1.RenderTests.Media
          InlineData(PixelFormatEnum.Gray4),
          InlineData(PixelFormatEnum.Gray8),
          InlineData(PixelFormatEnum.Gray16),
+         InlineData(PixelFormatEnum.Rgb24),
+         InlineData(PixelFormatEnum.Bgr24),
          InlineData(PixelFormatEnum.Gray32Float),
          InlineData(PixelFormatEnum.Rgba64),
          InlineData(PixelFormatEnum.Rgba64, AlphaFormat.Premul),