Merge pull request #3304 from AvaloniaUI/feature/osx-allow-access-to-nswindow-nsview-handles

[OSX] Allow access to NSView and NSWindow via platofom handle.

native/Avalonia.Native/inc/avalonia-native.h

@@ -212,6 +212,10 @@ AVNCOM(IAvnWindowBase, 02) : IUnknown
     virtual HRESULT GetSoftwareFramebuffer(AvnFramebuffer*ret) = 0;
     virtual HRESULT SetMainMenu(IAvnAppMenu* menu) = 0;
     virtual HRESULT ObtainMainMenu(IAvnAppMenu** retOut) = 0;
+    virtual HRESULT ObtainNSWindowHandle(void** retOut) = 0;
+    virtual HRESULT ObtainNSWindowHandleRetained(void** retOut) = 0;
+    virtual HRESULT ObtainNSViewHandle(void** retOut) = 0;
+    virtual HRESULT ObtainNSViewHandleRetained(void** retOut) = 0;
     virtual bool TryLock() = 0;
     virtual void Unlock() = 0;
 };

native/Avalonia.Native/src/OSX/window.mm

@@ -83,6 +83,54 @@ public:
         [Window setContentView: View];
     }
     
+    virtual HRESULT ObtainNSWindowHandle(void** ret) override
+    {
+        if (ret == nullptr)
+        {
+            return E_POINTER;
+        }
+        
+        *ret =  (__bridge void*)Window;
+        
+        return S_OK;
+    }
+    
+    virtual HRESULT ObtainNSWindowHandleRetained(void** ret) override
+    {
+        if (ret == nullptr)
+        {
+            return E_POINTER;
+        }
+        
+        *ret =  (__bridge_retained void*)Window;
+        
+        return S_OK;
+    }
+    
+    virtual HRESULT ObtainNSViewHandle(void** ret) override
+    {
+        if (ret == nullptr)
+        {
+            return E_POINTER;
+        }
+        
+        *ret =  (__bridge void*)View;
+        
+        return S_OK;
+    }
+    
+    virtual HRESULT ObtainNSViewHandleRetained(void** ret) override
+    {
+        if (ret == nullptr)
+        {
+            return E_POINTER;
+        }
+        
+        *ret =  (__bridge_retained void*)View;
+        
+        return S_OK;
+    }
+    
     virtual AvnWindow* GetNSWindow() override
     {
         return Window;

src/Avalonia.Base/Platform/IMacOSTopLevelPlatformHandle.cs

@@ -0,0 +1,15 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System;
+
+namespace Avalonia.Platform
+{
+    public interface IMacOSTopLevelPlatformHandle
+    {
+        IntPtr NSView { get; }
+        IntPtr GetNSViewRetained();
+        IntPtr NSWindow { get; }
+        IntPtr GetNSWindowRetained();
+    }
+}

src/Avalonia.Native/WindowImplBase.cs

@@ -16,6 +16,34 @@ using Avalonia.Threading;
 
 namespace Avalonia.Native
 {
+    public class MacOSTopLevelWindowHandle : IPlatformHandle, IMacOSTopLevelPlatformHandle
+    {
+        IAvnWindowBase _native;
+
+        public MacOSTopLevelWindowHandle(IAvnWindowBase native)
+        {
+            _native = native;
+        }
+
+        public IntPtr Handle => NSWindow;
+
+        public string HandleDescriptor => "NSWindow";
+
+        public IntPtr NSView => _native.ObtainNSViewHandle();
+
+        public IntPtr NSWindow => _native.ObtainNSWindowHandle();
+
+        public IntPtr GetNSViewRetained()
+        {
+            return _native.ObtainNSViewHandleRetained();
+        }
+
+        public IntPtr GetNSWindowRetained()
+        {
+            return _native.ObtainNSWindowHandleRetained();
+        }
+    }
+
     public abstract class WindowBaseImpl : IWindowBaseImpl,
         IFramebufferPlatformSurface
     {
@@ -45,6 +73,9 @@ namespace Avalonia.Native
         protected void Init(IAvnWindowBase window, IAvnScreens screens)
         {
             _native = window;
+
+            Handle = new MacOSTopLevelWindowHandle(window);
+            
             _glSurface = new GlPlatformSurface(window);
             Screen = new ScreenImpl(screens);
             _savedLogicalSize = ClientSize;
@@ -349,6 +380,6 @@ namespace Avalonia.Native
 
         }
 
-        public IPlatformHandle Handle => new PlatformHandle(IntPtr.Zero, "NOT SUPPORTED");
+        public IPlatformHandle Handle { get; private set; }
     }
 }