Fixes after VNC check

samples/ControlCatalog.NetCore/Properties/launchSettings.json

@@ -6,6 +6,10 @@
     "Dxgi": {
       "commandName": "Project",
       "commandLineArgs": "--dxgi"
+    },
+    "VNC": {
+      "commandName": "Project",
+      "commandLineArgs": "--vnc"
     }
   }
-}
+}

src/Headless/Avalonia.Headless.Vnc/HeadlessVncFramebufferSource.cs

@@ -69,7 +69,7 @@ namespace Avalonia.Headless.Vnc
         {
             lock (_lock)
             {
-                using (var bmpRef = Window.CaptureRenderedFrame())
+                using (var bmpRef = Window.GetLastRenderedFrame())
                 {
                     if (bmpRef == null)
                         return _framebuffer;

src/Headless/Avalonia.Headless/HeadlessWindowExtensions.cs

@@ -8,6 +8,9 @@ using Avalonia.Threading;
 
 namespace Avalonia.Headless;
 
+/// <summary>
+/// Set of extension methods to simplify usage of Avalonia.Headless platform.
+/// </summary>
 public static class HeadlessWindowExtensions
 {
     /// <summary>
@@ -20,7 +23,7 @@ public static class HeadlessWindowExtensions
         AvaloniaHeadlessPlatform.ForceRenderTimerTick();
         return topLevel.GetLastRenderedFrame();
     }
-    
+
     /// <summary>
     /// Reads last rendered frame.
     /// Note, in order to trigger rendering timer, call <see cref="AvaloniaHeadlessPlatform.ForceRenderTimerTick"/> method.  
@@ -30,7 +33,8 @@ public static class HeadlessWindowExtensions
     {
         if (AvaloniaLocator.Current.GetService<IPlatformRenderInterface>() is HeadlessPlatformRenderInterface)
         {
-            throw new NotSupportedException("To capture a rendered frame, make sure that headless application was initialized with '.UseSkia()' and disabled 'UseHeadlessDrawing' in the 'AvaloniaHeadlessPlatformOptions'.");
+            throw new NotSupportedException(
+                "To capture a rendered frame, make sure that headless application was initialized with '.UseSkia()' and disabled 'UseHeadlessDrawing' in the 'AvaloniaHeadlessPlatformOptions'.");
         }
 
         return GetImpl(topLevel).GetLastRenderedFrame();
@@ -40,49 +44,58 @@ public static class HeadlessWindowExtensions
     /// Simulates keyboard press on the headless window/toplevel.
     /// </summary>
     public static void KeyPress(this TopLevel topLevel, Key key, RawInputModifiers modifiers) =>
-        GetImpl(topLevel).KeyPress(key, modifiers);
+        RunJobsAndGetImpl(topLevel).KeyPress(key, modifiers);
 
     /// <summary>
     /// Simulates keyboard release on the headless window/toplevel.
     /// </summary>
     public static void KeyRelease(this TopLevel topLevel, Key key, RawInputModifiers modifiers) =>
-        GetImpl(topLevel).KeyRelease(key, modifiers);
+        RunJobsAndGetImpl(topLevel).KeyRelease(key, modifiers);
 
     /// <summary>
     /// Simulates mouse down on the headless window/toplevel.
     /// </summary>
     public static void MouseDown(this TopLevel topLevel, Point point, MouseButton button,
-        RawInputModifiers modifiers = RawInputModifiers.None) => GetImpl(topLevel).MouseDown(point, button, modifiers);
+        RawInputModifiers modifiers = RawInputModifiers.None) =>
+        RunJobsAndGetImpl(topLevel).MouseDown(point, button, modifiers);
 
     /// <summary>
     /// Simulates mouse move on the headless window/toplevel.
     /// </summary>
     public static void MouseMove(this TopLevel topLevel, Point point,
-        RawInputModifiers modifiers = RawInputModifiers.None) => GetImpl(topLevel).MouseMove(point, modifiers);
+        RawInputModifiers modifiers = RawInputModifiers.None) =>
+        RunJobsAndGetImpl(topLevel).MouseMove(point, modifiers);
 
     /// <summary>
     /// Simulates mouse up on the headless window/toplevel.
     /// </summary>
     public static void MouseUp(this TopLevel topLevel, Point point, MouseButton button,
-        RawInputModifiers modifiers = RawInputModifiers.None) => GetImpl(topLevel).MouseUp(point, button, modifiers);
+        RawInputModifiers modifiers = RawInputModifiers.None) =>
+        RunJobsAndGetImpl(topLevel).MouseUp(point, button, modifiers);
 
     /// <summary>
     /// Simulates mouse wheel on the headless window/toplevel.
     /// </summary>
     public static void MouseWheel(this TopLevel topLevel, Point point, Vector delta,
-        RawInputModifiers modifiers = RawInputModifiers.None) => GetImpl(topLevel).MouseWheel(point, delta, modifiers);
+        RawInputModifiers modifiers = RawInputModifiers.None) =>
+        RunJobsAndGetImpl(topLevel).MouseWheel(point, delta, modifiers);
 
     /// <summary>
     /// Simulates drag'n'drop target on the headless window/toplevel.
     /// </summary>
     public static void DragDrop(this TopLevel topLevel, Point point, RawDragEventType type, IDataObject data,
         DragDropEffects effects, RawInputModifiers modifiers = RawInputModifiers.None) =>
-        GetImpl(topLevel).DragDrop(point, type, data, effects, modifiers);
+        RunJobsAndGetImpl(topLevel).DragDrop(point, type, data, effects, modifiers);
 
-    private static IHeadlessWindow GetImpl(this TopLevel topLevel)
+    private static IHeadlessWindow RunJobsAndGetImpl(this TopLevel topLevel)
     {
         Dispatcher.UIThread.RunJobs();
+        return GetImpl(topLevel);
+    }
+
+    private static IHeadlessWindow GetImpl(this TopLevel topLevel)
+    {
         return topLevel.PlatformImpl as IHeadlessWindow ??
-            throw new InvalidOperationException("TopLevel must be a headless window.");
+               throw new InvalidOperationException("TopLevel must be a headless window.");
     }
 }