Only do manual layer fbo management on Windows

src/Avalonia.Headless/HeadlessPlatformRenderInterface.cs

@@ -272,6 +272,8 @@ namespace Avalonia.Headless
                 
             }
 
+            public bool CanBlit => false;
+
             public Vector Dpi { get; }
             public PixelSize PixelSize { get; }
             public int Version { get; set; }

src/Avalonia.Visuals/Platform/IDrawingContextImpl.cs

@@ -164,5 +164,10 @@ namespace Avalonia.Platform
         /// </summary>
         /// <param name="context"></param>
         void Blit(IDrawingContextImpl context);
+        
+        /// <summary>
+        /// Returns true if layer supports optimized blit
+        /// </summary>
+        bool CanBlit { get; }
     }
 }

src/Avalonia.Visuals/Rendering/DeferredRenderer.cs

@@ -502,7 +502,7 @@ namespace Avalonia.Rendering
 
                 if (layer.OpacityMask == null)
                 {
-                    if (firstLayer)
+                    if (firstLayer && bitmap.Item.CanBlit)
                         bitmap.Item.Blit(context);
                     else
                         context.DrawBitmap(bitmap, layer.Opacity, sourceRect, clientRect);

src/Skia/Avalonia.Skia/Gpu/ISkiaGpu.cs

@@ -28,8 +28,7 @@ namespace Avalonia.Skia
     {
         SKSurface Surface { get; }
         bool CanBlit { get; }
-        void Blit();
-
+        void Blit(SKCanvas canvas);
     }
 
     public interface IOpenGlAwareSkiaGpu : ISkiaGpu

src/Skia/Avalonia.Skia/Gpu/OpenGl/FboSkiaSurface.cs

@@ -116,8 +116,13 @@ namespace Avalonia.Skia
 
         public SKSurface Surface { get; private set; }
         public bool CanBlit { get; }
-        public void Blit()
+        public void Blit(SKCanvas canvas)
         {
+            // This should set the render target as the current FBO
+            // which is definitely not the best method, but it works
+            canvas.Clear();
+            canvas.Flush();
+            
             var gl = _glContext.GlInterface;
             gl.GetIntegerv(GL_READ_FRAMEBUFFER_BINDING, out var oldRead);
             gl.BindFramebuffer(GL_READ_FRAMEBUFFER, _fbo);

src/Skia/Avalonia.Skia/Gpu/OpenGl/GlSkiaGpu.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Runtime.InteropServices;
 using Avalonia.Logging;
 using Avalonia.OpenGL;
 using Avalonia.OpenGL.Imaging;
@@ -48,6 +49,14 @@ namespace Avalonia.Skia
 
         public ISkiaSurface TryCreateSurface(PixelSize size)
         {
+            // Only windows platform needs our FBO trickery
+            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                return null;
+
+            // Blit feature requires glBlitFramebuffer
+            if (_glContext.GlInterface.BlitFramebuffer == null)
+                return null;
+            
             size = new PixelSize(Math.Max(size.Width, 1), Math.Max(size.Height, 1));
             if (_canCreateSurfaces == false)
                 return null;

src/Skia/Avalonia.Skia/SurfaceRenderTarget.cs

@@ -23,20 +23,18 @@ namespace Avalonia.Skia
         class SkiaSurfaceWrapper : ISkiaSurface
         {
             public SKSurface Surface { get; private set; }
-            public SKSurface ReadSurface { get; private set; }
             public bool CanBlit => false;
-            public void Blit() => throw new NotSupportedException();
+            public void Blit(SKCanvas canvas) => throw new NotSupportedException();
 
             public SkiaSurfaceWrapper(SKSurface surface)
             {
-                Surface = ReadSurface = surface;
+                Surface = surface;
             }
 
             public void Dispose()
             {
                 Surface?.Dispose();
                 Surface = null;
-                ReadSurface = null;
             }
         }
         
@@ -141,11 +139,7 @@ namespace Avalonia.Skia
             if (_surface.CanBlit)
             {
                 _surface.Surface.Canvas.Flush();
-                
-                // This should set the render target as the current FBO
-                context.Canvas.Clear();
-                context.Canvas.Flush();
-                _surface.Blit();
+                _surface.Blit(context.Canvas);
             }
             else
             {
@@ -155,7 +149,9 @@ namespace Avalonia.Skia
                 context.Canvas.SetMatrix(oldMatrix);
             }
         }
-        
+
+        public bool CanBlit => true;
+
         /// <inheritdoc />
         public void Draw(DrawingContextImpl context, SKRect sourceRect, SKRect destRect, SKPaint paint)
         {

src/Windows/Avalonia.Direct2D1/Media/Imaging/D2DRenderTargetBitmapImpl.cs

@@ -1,4 +1,5 @@
-using System.IO;
+using System;
+using System.IO;
 using Avalonia.Platform;
 using Avalonia.Rendering;
 using Avalonia.Utilities;
@@ -34,12 +35,9 @@ namespace Avalonia.Direct2D1.Media.Imaging
             return new DrawingContextImpl(visualBrushRenderer, this, _renderTarget, null, () => Version++);
         }
 
-        public void Blit(IDrawingContextImpl context)
-        {
-            var rc = new Rect(0, 0, PixelSize.Width, PixelSize.Height);
-            context.DrawBitmap(RefCountable.CreateUnownedNotClonable(this),
-                1, rc, rc);
-        }
+        public void Blit(IDrawingContextImpl context) => throw new NotSupportedException();
+
+        public bool CanBlit => false;
 
         public IDrawingContextLayerImpl CreateLayer(Size size)
         {