Merge branch 'rndr4' of github.com:AvaloniaUI/Avalonia into rndr4

build/ApiCompatAttributeExcludeList.txt

@@ -0,0 +1,2 @@
+T:Avalonia.Metadata.NotClientImplementableAttribute
+T:Avalonia.Metadata.UnstableAttribute

build/CoreLibraries.props

@@ -3,8 +3,6 @@
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.Base/Avalonia.Base.csproj" />
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.Controls/Avalonia.Controls.csproj" />
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.DesignerSupport/Avalonia.DesignerSupport.csproj" />
-      <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.Themes.Default/Avalonia.Themes.Default.csproj" />
-      <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.Themes.Fluent/Avalonia.Themes.Fluent.csproj" />
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.OpenGL/Avalonia.OpenGL.csproj" />
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.Dialogs/Avalonia.Dialogs.csproj" />
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Markup/Avalonia.Markup/Avalonia.Markup.csproj" />

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

@@ -85,7 +85,7 @@
     _settingSize = true;
     [super setFrameSize:newSize];
 
-    auto window = static_cast<id <AvnWindowProtocol>>([self window]);
+    auto window = (id <AvnWindowProtocol>) [self window];
 
     // TODO get actual titlebar size
 

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

@@ -174,6 +174,11 @@
     [self setBackgroundColor: [NSColor clearColor]];
 
     _isExtended = false;
+
+#ifdef IS_NSPANEL
+    [self setCollectionBehavior:NSWindowCollectionBehaviorCanJoinAllSpaces|NSWindowCollectionBehaviorFullScreenAuxiliary];
+#endif
+
     return self;
 }
 
@@ -194,6 +199,8 @@
     [self backingScaleFactor];
 }
 
+
+
 - (void)windowWillClose:(NSNotification *)notification
 {
     _closed = true;
@@ -212,11 +219,14 @@
     // If the window has a child window being shown as a dialog then don't allow it to become the key window.
     for(NSWindow* uch in [self childWindows])
     {
-        auto ch = static_cast<id <AvnWindowProtocol>>(uch);
+        if (![uch conformsToProtocol:@protocol(AvnWindowProtocol)])
-        if(ch == nil)
+        {
             continue;
-        if (ch.isDialog)
+        }
-            return false;
+
+        id <AvnWindowProtocol> ch = (id <AvnWindowProtocol>) uch;
+
+        return !ch.isDialog;
     }
 
     return true;
@@ -372,6 +382,11 @@
 
         if(cparent != nullptr)
         {
+            if(!cparent->IsShown())
+            {
+                return;
+            }
+
             if(cparent->WindowState() == Maximized)
             {
                 cparent->SetWindowState(Normal);

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

@@ -50,11 +50,17 @@ protected:
             return S_OK;
         }
     }
+
 public:
     virtual bool ShouldTakeFocusOnShow() override
     {
         return false;
     }
+
+    virtual HRESULT Show(bool activate, bool isDialog) override
+    {
+        return WindowBaseImpl::Show(activate, true);
+    }
 };
 
 

native/Avalonia.Native/src/OSX/WindowBaseImpl.h

@@ -60,6 +60,8 @@ BEGIN_INTERFACE_MAP()
 
     virtual HRESULT Show(bool activate, bool isDialog) override;
 
+    virtual bool IsShown ();
+
     virtual bool ShouldTakeFocusOnShow();
 
     virtual HRESULT Hide() override;

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

@@ -30,8 +30,8 @@ WindowBaseImpl::WindowBaseImpl(IAvnWindowBaseEvents *events, IAvnGlContext *gl)
     View = [[AvnView alloc] initWithParent:this];
     StandardContainer = [[AutoFitContentView new] initWithContent:View];
 
-    lastPositionSet.X = 100;
+    lastPositionSet.X = -1;
-    lastPositionSet.Y = 100;
+    lastPositionSet.Y = -1;
     lastSize = NSSize { 100, 100 };
     lastMaxSize = NSSize { CGFLOAT_MAX, CGFLOAT_MAX};
     lastMinSize = NSSize { 0, 0 };
@@ -92,7 +92,11 @@ HRESULT WindowBaseImpl::Show(bool activate, bool isDialog) {
         CreateNSWindow(isDialog);
         InitialiseNSWindow();
 
-        SetPosition(lastPositionSet);
+        if(lastPositionSet.X >= 0 && lastPositionSet.Y >= 0)
+        {
+            SetPosition(lastPositionSet);
+        }
+
         UpdateStyle();
 
         [Window setTitle:_lastTitle];
@@ -112,6 +116,11 @@ HRESULT WindowBaseImpl::Show(bool activate, bool isDialog) {
     }
 }
 
+bool WindowBaseImpl::IsShown ()
+{
+    return _shown;
+}
+
 bool WindowBaseImpl::ShouldTakeFocusOnShow() {
     return true;
 }
@@ -191,9 +200,8 @@ HRESULT WindowBaseImpl::GetClientSize(AvnSize *ret) {
         if (ret == nullptr)
             return E_POINTER;
 
-        auto frame = [View frame];
+        ret->Width = lastSize.width;
-        ret->Width = frame.size.width;
+        ret->Height = lastSize.height;
-        ret->Height = frame.size.height;
 
         return S_OK;
     }
@@ -206,9 +214,11 @@ HRESULT WindowBaseImpl::GetFrameSize(AvnSize *ret) {
         if (ret == nullptr)
             return E_POINTER;
 
-        auto frame = [Window frame];
+        if(Window != nullptr){
-        ret->Width = frame.size.width;
+            auto frame = [Window frame];
-        ret->Height = frame.size.height;
+            ret->Width = frame.size.width;
+            ret->Height = frame.size.height;
+        }
 
         return S_OK;
     }
@@ -354,12 +364,17 @@ HRESULT WindowBaseImpl::GetPosition(AvnPoint *ret) {
             return E_POINTER;
         }
 
-        auto frame = [Window frame];
+        if(Window != nullptr) {
+            auto frame = [Window frame];
 
-        ret->X = frame.origin.x;
+            ret->X = frame.origin.x;
-        ret->Y = frame.origin.y + frame.size.height;
+            ret->Y = frame.origin.y + frame.size.height;
 
-        *ret = ConvertPointY(*ret);
+            *ret = ConvertPointY(*ret);
+        } else
+        {
+            *ret = lastPositionSet;
+        }
 
         return S_OK;
     }
@@ -370,7 +385,10 @@ HRESULT WindowBaseImpl::SetPosition(AvnPoint point) {
 
     @autoreleasepool {
         lastPositionSet = point;
-        [Window setFrameTopLeftPoint:ToNSPoint(ConvertPointY(point))];
+
+        if(Window != nullptr) {
+            [Window setFrameTopLeftPoint:ToNSPoint(ConvertPointY(point))];
+        }
 
         return S_OK;
     }
@@ -559,6 +577,7 @@ void WindowBaseImpl::InitialiseNSWindow() {
         [Window setContentMaxSize:lastMaxSize];
 
         [Window setOpaque:false];
+        [Window center];
 
         if (lastMenu != nullptr) {
             [GetWindowProtocol() applyMenu:lastMenu];
@@ -576,7 +595,7 @@ id <AvnWindowProtocol> WindowBaseImpl::GetWindowProtocol() {
         return nullptr;
     }
 
-    return static_cast<id <AvnWindowProtocol>>(Window);
+    return (id <AvnWindowProtocol>) Window;
 }
 
 extern IAvnWindow* CreateAvnWindow(IAvnWindowEvents*events, IAvnGlContext* gl)

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

@@ -430,6 +430,9 @@ HRESULT WindowImpl::SetWindowState(AvnWindowState state) {
     START_COM_CALL;
 
     @autoreleasepool {
+        auto currentState = _actualWindowState;
+        _lastWindowState = state;
+
         if (Window == nullptr) {
             return S_OK;
         }
@@ -440,9 +443,6 @@ HRESULT WindowImpl::SetWindowState(AvnWindowState state) {
 
         _inSetWindowState = true;
 
-        auto currentState = _actualWindowState;
-        _lastWindowState = state;
-
         if (currentState == Normal) {
             _preZoomSize = [Window frame];
         }

samples/BindingDemo/BindingDemo.csproj

@@ -5,6 +5,7 @@
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
     <ProjectReference Include="..\..\src\Linux\Avalonia.LinuxFramebuffer\Avalonia.LinuxFramebuffer.csproj" />
     <ProjectReference Include="..\MiniMvvm\MiniMvvm.csproj" />
   </ItemGroup>

samples/ControlCatalog/ControlCatalog.csproj

@@ -25,6 +25,8 @@
     <ProjectReference Include="..\..\packages\Avalonia\Avalonia.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Controls.ColorPicker\Avalonia.Controls.ColorPicker.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Controls.DataGrid\Avalonia.Controls.DataGrid.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Fluent\Avalonia.Themes.Fluent.csproj" />
     <ProjectReference Include="..\MiniMvvm\MiniMvvm.csproj" />
     <ProjectReference Include="..\SampleControls\ControlSamples.csproj" />
   </ItemGroup>

samples/ControlCatalog/Pages/CalendarDatePickerPage.xaml

@@ -10,8 +10,7 @@
                 Margin="0,16,0,0"
                 HorizontalAlignment="Center"
                 Spacing="16">
-      <StackPanel Orientation="Vertical"
+      <StackPanel Orientation="Vertical">
-                  Width="200">
         <TextBlock Text="SelectedDateFormat: Short"/>
         <CalendarDatePicker Name="DatePicker1"
                     SelectedDateFormat="Short"

samples/ControlCatalog/Pages/TextBoxPage.xaml

@@ -66,6 +66,12 @@
                  FontFamily="Comic Sans MS"
                  InputMethod.IsInputMethodEnabled="False"
                  Foreground="Red"/>
+        <TextBox AcceptsReturn="True" 
+                 TextWrapping="Wrap" 
+                 Width="200" 
+                 Height="125"
+                 LineHeight="32"
+                 Text="Multiline TextBox with TextWrapping and increased LineHeight.&#xD;&#xD;Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus magna. Cras in mi at felis aliquet congue. Ut a est eget ligula molestie gravida. Curabitur massa. Donec eleifend, libero at sagittis mollis, tellus est malesuada tellus, at luctus turpis elit sit amet quam. Vivamus pretium ornare est." />
       </StackPanel>
       <StackPanel Orientation="Vertical" Spacing="8" Margin="8">
         <Label Classes="h2" Target="{Binding #firstResMFont}">res_m fonts</Label>

samples/IntegrationTestApp/IntegrationTestApp.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
@@ -18,6 +18,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Fluent\Avalonia.Themes.Fluent.csproj" />
   </ItemGroup>
   
   <Import Project="..\..\build\BuildTargets.targets" />

samples/PlatformSanityChecks/PlatformSanityChecks.csproj

@@ -7,6 +7,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Desktop\Avalonia.Desktop.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.X11\Avalonia.X11.csproj" />
   </ItemGroup>
 

samples/Previewer/Previewer.csproj

@@ -9,6 +9,9 @@
     </Compile>
     <EmbeddedResource Include="**\*.xaml" />
   </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
+  </ItemGroup>
   
   <Import Project="..\..\build\SampleApp.props" />
   <Import Project="..\..\build\ReferenceCoreLibraries.props" />

samples/RenderDemo/RenderDemo.csproj

@@ -12,6 +12,7 @@
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Fluent\Avalonia.Themes.Fluent.csproj" />
     <ProjectReference Include="..\..\src\Linux\Avalonia.LinuxFramebuffer\Avalonia.LinuxFramebuffer.csproj" />
     <ProjectReference Include="..\MiniMvvm\MiniMvvm.csproj" />
     <ProjectReference Include="..\SampleControls\ControlSamples.csproj" />

samples/Sandbox/Sandbox.csproj

@@ -10,6 +10,7 @@
     <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Controls.ColorPicker\Avalonia.Controls.ColorPicker.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Controls.DataGrid\Avalonia.Controls.DataGrid.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Fluent\Avalonia.Themes.Fluent.csproj" />
   </ItemGroup>
   
   <Import Project="..\..\build\SampleApp.props" />

samples/VirtualizationDemo/VirtualizationDemo.csproj

@@ -5,6 +5,7 @@
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
     <ProjectReference Include="..\..\src\Linux\Avalonia.LinuxFramebuffer\Avalonia.LinuxFramebuffer.csproj" />
     <ProjectReference Include="..\MiniMvvm\MiniMvvm.csproj" />
   </ItemGroup>

samples/interop/Direct3DInteropSample/Direct3DInteropSample.csproj

@@ -22,6 +22,7 @@
       </EmbeddedResource>
     </ItemGroup>
     <ItemGroup>
+        <ProjectReference Include="..\..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
         <ProjectReference Include="..\..\..\src\Windows\Avalonia.Direct2D1\Avalonia.Direct2D1.csproj" />
         <ProjectReference Include="..\..\..\src\Windows\Avalonia.Win32\Avalonia.Win32.csproj" />
         <ProjectReference Include="..\..\MiniMvvm\MiniMvvm.csproj" />

samples/interop/NativeEmbedSample/NativeEmbedSample.csproj

@@ -9,6 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="MonoMac.NetStandard" Version="0.0.4" />
+    <ProjectReference Include="..\..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
     <ProjectReference Include="..\..\..\src\Windows\Avalonia.Direct2D1\Avalonia.Direct2D1.csproj" />
     <ProjectReference Include="..\..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
     <ProjectReference Include="..\..\..\src\Avalonia.X11\Avalonia.X11.csproj" />

src/Avalonia.Base/Animation/IAnimation.cs

@@ -1,12 +1,14 @@
 using System;
 using System.Threading;
 using System.Threading.Tasks;
+using Avalonia.Metadata;
 
 namespace Avalonia.Animation
 {
     /// <summary>
     /// Interface for Animation objects
     /// </summary>
+    [NotClientImplementable]
     public interface IAnimation
     {
         /// <summary>

src/Avalonia.Base/Animation/IAnimationSetter.cs

@@ -1,5 +1,8 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Animation
 {
+    [NotClientImplementable]
     public interface IAnimationSetter
     {
         AvaloniaProperty? Property { get; set; }

src/Avalonia.Base/Animation/IAnimator.cs

@@ -1,11 +1,13 @@
 using System;
 using System.Collections.Generic;
+using Avalonia.Metadata;
 
 namespace Avalonia.Animation
 {
     /// <summary>
     /// Interface for Animator objects
     /// </summary>
+    [NotClientImplementable]
     public interface IAnimator : IList<AnimatorKeyFrame>
     {
         /// <summary>

src/Avalonia.Base/Animation/IClock.cs

@@ -1,9 +1,9 @@
 using System;
-using System.Collections.Generic;
+using Avalonia.Metadata;
-using System.Text;
 
 namespace Avalonia.Animation
 {
+    [NotClientImplementable]
     public interface IClock : IObservable<TimeSpan>
     {
         PlayState PlayState { get; set; }

src/Avalonia.Base/Animation/IGlobalClock.cs

@@ -1,9 +1,8 @@
-using System;
+using Avalonia.Metadata;
-using System.Collections.Generic;
-using System.Text;
 
 namespace Avalonia.Animation
 {
+    [NotClientImplementable]
     public interface IGlobalClock : IClock
     {
     }

src/Avalonia.Base/Animation/ITransition.cs

@@ -1,10 +1,12 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Animation
 {
     /// <summary>
     /// Interface for Transition objects.
     /// </summary>
+    [NotClientImplementable]
     public interface ITransition
     {
         /// <summary>

src/Avalonia.Base/Collections/AvaloniaList.cs

@@ -394,7 +394,13 @@ namespace Avalonia.Collections
                         } while (en.MoveNext());
 
                         if (notificationItems is not null)
+                        {
                             NotifyAdd(notificationItems, index);
+                        }
+                        else
+                        {
+                            NotifyCountChanged();
+                        }
                     }
                 }
             }

src/Avalonia.Base/Controls/INameScope.cs

@@ -1,5 +1,4 @@
-using System;
+using Avalonia.Metadata;
-using System.Threading.Tasks;
 using Avalonia.Utilities;
 
 namespace Avalonia.Controls
@@ -7,6 +6,7 @@ namespace Avalonia.Controls
     /// <summary>
     /// Defines a name scope.
     /// </summary>
+    [NotClientImplementable]
     public interface INameScope
     {
         /// <summary>

src/Avalonia.Base/Controls/IPseudoClasses.cs

@@ -1,9 +1,11 @@
+using Avalonia.Metadata;
 
 namespace Avalonia.Controls
 {
     /// <summary>
     /// Exposes an interface for setting pseudoclasses on a <see cref="Classes"/> collection.
     /// </summary>
+    [NotClientImplementable]
     public interface IPseudoClasses
     {
         /// <summary>

src/Avalonia.Base/Controls/IResourceHost.cs

@@ -1,6 +1,5 @@
 using System;
-
+using Avalonia.Metadata;
-#nullable enable
 
 namespace Avalonia.Controls
 {
@@ -10,6 +9,7 @@ namespace Avalonia.Controls
     /// <remarks>
     /// This interface is implemented by <see cref="StyledElement"/> and `Application`.
     /// </remarks>
+    [NotClientImplementable]
     public interface IResourceHost : IResourceNode
     {
         /// <summary>

src/Avalonia.Base/Controls/IResourceNode.cs

@@ -1,6 +1,5 @@
 using System;
-
+using Avalonia.Metadata;
-#nullable enable
 
 namespace Avalonia.Controls
 {
@@ -12,6 +11,7 @@ namespace Avalonia.Controls
     /// (<see cref="IResourceHost"/>) and resource providers such as <see cref="ResourceDictionary"/>
     /// (see <see cref="IResourceProvider"/>).
     /// </remarks>
+    [NotClientImplementable]
     public interface IResourceNode
     {
         /// <summary>

src/Avalonia.Base/Controls/ISetInheritanceParent.cs

@@ -1,4 +1,4 @@
-#nullable enable
+using Avalonia.Metadata;
 
 namespace Avalonia.Controls
 {
@@ -10,6 +10,7 @@ namespace Avalonia.Controls
     /// Additionally, <see cref="ISetLogicalParent"/> also sets the inheritance parent; this
     /// interface is only needed where the logical and inheritance parents differ.
     /// </remarks>
+    [NotClientImplementable]
     public interface ISetInheritanceParent
     {
         /// <summary>

src/Avalonia.Base/Controls/ISetLogicalParent.cs

@@ -1,6 +1,5 @@
 using Avalonia.LogicalTree;
-
+using Avalonia.Metadata;
-#nullable enable
 
 namespace Avalonia.Controls
 {
@@ -10,6 +9,7 @@ namespace Avalonia.Controls
     /// <remarks>
     /// You should not usually need to use this interface - it is for advanced scenarios only.
     /// </remarks>
+    [NotClientImplementable]
     public interface ISetLogicalParent
     {
         /// <summary>

src/Avalonia.Base/Data/Core/IPropertyInfo.cs

@@ -1,7 +1,9 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Data.Core
 {
+    [NotClientImplementable]
     public interface IPropertyInfo
     {
         string Name { get; }

src/Avalonia.Base/Data/Core/Plugins/InpcPropertyAccessorPlugin.cs

@@ -17,7 +17,7 @@ namespace Avalonia.Data.Core.Plugins
             new Dictionary<(Type, string), PropertyInfo?>();
 
         /// <inheritdoc/>
-        public bool Match(object obj, string propertyName) => GetFirstPropertyWithName(obj.GetType(), propertyName) != null;
+        public bool Match(object obj, string propertyName) => GetFirstPropertyWithName(obj, propertyName) != null;
 
         /// <summary>
         /// Starts monitoring the value of a property on an object.
@@ -36,7 +36,7 @@ namespace Avalonia.Data.Core.Plugins
             if (!reference.TryGetTarget(out var instance) || instance is null)
                 return null;
 
-            var p = GetFirstPropertyWithName(instance.GetType(), propertyName);
+            var p = GetFirstPropertyWithName(instance, propertyName);
 
             if (p != null)
             {
@@ -50,8 +50,16 @@ namespace Avalonia.Data.Core.Plugins
             }
         }
 
-        private PropertyInfo? GetFirstPropertyWithName(Type type, string propertyName)
+        private const BindingFlags PropertyBindingFlags =
+            BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance;
+        
+        private PropertyInfo? GetFirstPropertyWithName(object instance, string propertyName)
         {
+            if (instance is IReflectableType reflectableType)
+                return reflectableType.GetTypeInfo().GetProperty(propertyName, PropertyBindingFlags);
+
+            var type = instance.GetType();
+            
             var key = (type, propertyName);
 
             if (!_propertyLookup.TryGetValue(key, out var propertyInfo))
@@ -66,10 +74,7 @@ namespace Avalonia.Data.Core.Plugins
         {
             PropertyInfo? found = null;
 
-            const BindingFlags bindingFlags =
+            var properties = type.GetProperties(PropertyBindingFlags);
-                BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance;
-
-            var properties = type.GetProperties(bindingFlags);
 
             foreach (PropertyInfo propertyInfo in properties)
             {

src/Avalonia.Base/Data/IBinding.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Data
 {
     /// <summary>
     /// Holds a binding that can be applied to a property on an object.
     /// </summary>
+    [NotClientImplementable]
     public interface IBinding
     {
         /// <summary>

src/Avalonia.Base/DirectPropertyBase.cs

@@ -2,7 +2,6 @@
 using Avalonia.Data;
 using Avalonia.Reactive;
 using Avalonia.Styling;
-using Avalonia.Utilities;
 
 namespace Avalonia
 {
@@ -188,10 +187,10 @@ namespace Avalonia
             }
             else if (value is ITemplate template && !typeof(ITemplate).IsAssignableFrom(PropertyType))
             {
-                return new PropertySetterLazyInstance<TValue>(
+                return new PropertySetterTemplateInstance<TValue>(
                     target,
                     this,
-                    () => (TValue)template.Build());
+                    template);
             }
             else
             {

src/Avalonia.Base/IAvaloniaObject.cs

@@ -1,11 +1,13 @@
 using System;
 using Avalonia.Data;
+using Avalonia.Metadata;
 
 namespace Avalonia
 {
     /// <summary>
     /// Interface for getting/setting <see cref="AvaloniaProperty"/> values on an object.
     /// </summary>
+    [NotClientImplementable]
     public interface IAvaloniaObject
     {
         /// <summary>

src/Avalonia.Base/IDataContextProvider.cs

@@ -1,10 +1,11 @@
-#nullable enable
+using Avalonia.Metadata;
 
 namespace Avalonia
 {
     /// <summary>
     /// Defines an element with a data context that can be used for binding.
     /// </summary>
+    [NotClientImplementable]
     public interface IDataContextProvider : IAvaloniaObject
     {
         /// <summary>

src/Avalonia.Base/IDirectPropertyAccessor.cs

@@ -1,4 +1,5 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia
 {

src/Avalonia.Base/IDirectPropertyMetadata.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia
 {
     /// <summary>
     /// Untyped interface to <see cref="DirectPropertyMetadata{TValue}"/>
     /// </summary>
+    [NotClientImplementable]
     public interface IDirectPropertyMetadata
     {
         /// <summary>

src/Avalonia.Base/IStyledElement.cs

@@ -2,12 +2,12 @@
 using System.ComponentModel;
 using Avalonia.Controls;
 using Avalonia.LogicalTree;
+using Avalonia.Metadata;
 using Avalonia.Styling;
 
-#nullable enable
-
 namespace Avalonia
 {
+    [NotClientImplementable]
     public interface IStyledElement :
         IStyleable,
         IStyleHost,

src/Avalonia.Base/IStyledPropertyMetadata.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia
 {
     /// <summary>
     /// Untyped interface to <see cref="StyledPropertyMetadata{TValue}"/>
     /// </summary>
+    [NotClientImplementable]
     public interface IStyledPropertyMetadata
     {
         /// <summary>

src/Avalonia.Base/Input/IAccessKeyHandler.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input
 {
     /// <summary>
     /// Defines the interface for classes that handle access keys for a window.
     /// </summary>
+    [Unstable]
     public interface IAccessKeyHandler
     {
         /// <summary>

src/Avalonia.Base/Input/IFocusManager.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input
 {
     /// <summary>
     /// Manages focus for the application.
     /// </summary>
+    [NotClientImplementable]
     public interface IFocusManager
     {
         /// <summary>

src/Avalonia.Base/Input/IInputDevice.cs

@@ -1,7 +1,9 @@
 using Avalonia.Input.Raw;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
+    [NotClientImplementable]
     public interface IInputDevice
     {
         /// <summary>

src/Avalonia.Base/Input/IInputElement.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Avalonia.Interactivity;
+using Avalonia.Metadata;
 using Avalonia.VisualTree;
 
 #nullable enable
@@ -10,6 +11,7 @@ namespace Avalonia.Input
     /// <summary>
     /// Defines input-related functionality for a control.
     /// </summary>
+    [NotClientImplementable]
     public interface IInputElement : IInteractive, IVisual
     {
         /// <summary>

src/Avalonia.Base/Input/IInputManager.cs

@@ -1,5 +1,6 @@
 using System;
 using Avalonia.Input.Raw;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
@@ -7,6 +8,7 @@ namespace Avalonia.Input
     /// Receives input from the windowing subsystem and dispatches it to interested parties
     /// for processing.
     /// </summary>
+    [NotClientImplementable]
     public interface IInputManager
     {
         /// <summary>

src/Avalonia.Base/Input/IInputRoot.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input
 {
     /// <summary>
     /// Defines the interface for top-level input elements.
     /// </summary>
+    [NotClientImplementable]
     public interface IInputRoot : IInputElement
     {
         /// <summary>

src/Avalonia.Base/Input/IKeyboardDevice.cs

@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
@@ -50,6 +51,7 @@ namespace Avalonia.Input
         KeyboardMask = Alt | Control | Shift | Meta
     }
 
+    [NotClientImplementable]
     public interface IKeyboardDevice : IInputDevice, INotifyPropertyChanged
     {
         IInputElement? FocusedElement { get; }

src/Avalonia.Base/Input/IKeyboardNavigationHandler.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input
 {
     /// <summary>
     /// Defines the interface for classes that handle keyboard navigation for a window.
     /// </summary>
+    [Unstable]
     public interface IKeyboardNavigationHandler
     {
         /// <summary>

src/Avalonia.Base/Input/IMainMenu.cs

@@ -1,5 +1,6 @@
 using System;
 using Avalonia.Interactivity;
+using Avalonia.Metadata;
 using Avalonia.VisualTree;
 
 namespace Avalonia.Input
@@ -7,6 +8,7 @@ namespace Avalonia.Input
     /// <summary>
     /// Defines the interface for a window's main menu.
     /// </summary>
+    [NotClientImplementable]
     public interface IMainMenu : IVisual
     {
         /// <summary>

src/Avalonia.Base/Input/IMouseDevice.cs

@@ -1,10 +1,12 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
     /// <summary>
     /// Represents a mouse device.
     /// </summary>
+    [NotClientImplementable]
     public interface IMouseDevice : IPointerDevice
     {
         /// <summary>

src/Avalonia.Base/Input/IPointer.cs

@@ -1,5 +1,8 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input
 {
+    [NotClientImplementable]
     public interface IPointer
     {
         int Id { get; }

src/Avalonia.Base/Input/IPointerDevice.cs

@@ -1,9 +1,11 @@
 using System;
 using Avalonia.VisualTree;
 using Avalonia.Input.Raw;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
+    [NotClientImplementable]
     public interface IPointerDevice : IInputDevice
     {
         /// <inheritdoc cref="IPointer.Captured" />

src/Avalonia.Base/Input/InputElement.cs

@@ -94,7 +94,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<KeyEventArgs> KeyDownEvent =
             RoutedEvent.Register<InputElement, KeyEventArgs>(
-                "KeyDown",
+                nameof(KeyDown),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>
@@ -102,7 +102,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<KeyEventArgs> KeyUpEvent =
             RoutedEvent.Register<InputElement, KeyEventArgs>(
-                "KeyUp",
+                nameof(KeyUp),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>
@@ -116,7 +116,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<TextInputEventArgs> TextInputEvent =
             RoutedEvent.Register<InputElement, TextInputEventArgs>(
-                "TextInput",
+                nameof(TextInput),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
         
         /// <summary>
@@ -124,7 +124,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<TextInputMethodClientRequestedEventArgs> TextInputMethodClientRequestedEvent =
             RoutedEvent.Register<InputElement, TextInputMethodClientRequestedEventArgs>(
-                "TextInputMethodClientRequested",
+                nameof(TextInputMethodClientRequested),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>
@@ -144,7 +144,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<PointerEventArgs> PointerMovedEvent =
             RoutedEvent.Register<InputElement, PointerEventArgs>(
-                "PointerMove",
+                nameof(PointerMoved),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>
@@ -152,7 +152,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<PointerPressedEventArgs> PointerPressedEvent =
             RoutedEvent.Register<InputElement, PointerPressedEventArgs>(
-                "PointerPressed",
+                nameof(PointerPressed),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>
@@ -160,7 +160,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<PointerReleasedEventArgs> PointerReleasedEvent =
             RoutedEvent.Register<InputElement, PointerReleasedEventArgs>(
-                "PointerReleased",
+                nameof(PointerReleased),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
         
         /// <summary>
@@ -168,7 +168,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<PointerCaptureLostEventArgs> PointerCaptureLostEvent =
             RoutedEvent.Register<InputElement, PointerCaptureLostEventArgs>(
-                "PointerCaptureLost", 
+                nameof(PointerCaptureLost), 
                 RoutingStrategies.Direct);
 
         /// <summary>
@@ -176,7 +176,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<PointerWheelEventArgs> PointerWheelChangedEvent =
             RoutedEvent.Register<InputElement, PointerWheelEventArgs>(
-                "PointerWheelChanged",
+                nameof(PointerWheelChanged),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>

src/Avalonia.Base/Input/Platform/IClipboard.cs

@@ -1,7 +1,9 @@
 using System.Threading.Tasks;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input.Platform
 {
+    [NotClientImplementable]
     public interface IClipboard
     {
         Task<string> GetTextAsync();

src/Avalonia.Base/Input/Platform/IPlatformDragSource.cs

@@ -1,7 +1,9 @@
 using System.Threading.Tasks;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input.Platform
 {
+    [Unstable]
     public interface IPlatformDragSource
     {
         Task<DragDropEffects> DoDragDrop(PointerEventArgs triggerEvent, IDataObject data, DragDropEffects allowedEffects);

src/Avalonia.Base/Input/Raw/IDragDropDevice.cs

@@ -1,5 +1,8 @@
-namespace Avalonia.Input.Raw
+using Avalonia.Metadata;
+
+namespace Avalonia.Input.Raw
 {
+    [NotClientImplementable]
     public interface IDragDropDevice : IInputDevice
     {
     }

src/Avalonia.Base/Input/TextInput/ITextInputMethodImpl.cs

@@ -1,5 +1,8 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input.TextInput
 {
+    [Unstable]
     public interface ITextInputMethodImpl
     {
         void SetClient(ITextInputMethodClient? client);
@@ -8,6 +11,7 @@ namespace Avalonia.Input.TextInput
         void Reset();
     }
     
+    [NotClientImplementable]
     public interface ITextInputMethodRoot : IInputRoot
     {
         ITextInputMethodImpl? InputMethod { get; }

src/Avalonia.Base/Interactivity/IInteractive.cs

@@ -1,4 +1,5 @@
 using System;
+using Avalonia.Metadata;
 
 #nullable enable
 
@@ -7,6 +8,7 @@ namespace Avalonia.Interactivity
     /// <summary>
     /// Interface for objects that raise routed events.
     /// </summary>
+    [NotClientImplementable]
     public interface IInteractive
     {
         /// <summary>

src/Avalonia.Base/Layout/ILayoutManager.cs

@@ -1,12 +1,12 @@
 using System;
-
+using Avalonia.Metadata;
-#nullable enable
 
 namespace Avalonia.Layout
 {
     /// <summary>
     /// Manages measuring and arranging of controls.
     /// </summary>
+    [NotClientImplementable]
     public interface ILayoutManager : IDisposable
     {
         /// <summary>

src/Avalonia.Base/Layout/ILayoutRoot.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Layout
 {
     /// <summary>
     /// Defines the root of a layoutable tree.
     /// </summary>
+    [NotClientImplementable]
     public interface ILayoutRoot : ILayoutable
     {
         /// <summary>

src/Avalonia.Base/Layout/ILayoutable.cs

@@ -1,12 +1,12 @@
+using Avalonia.Metadata;
 using Avalonia.VisualTree;
 
-#nullable enable
-
 namespace Avalonia.Layout
 {
     /// <summary>
     /// Defines layout-related functionality for a control.
     /// </summary>
+    [NotClientImplementable]
     public interface ILayoutable : IVisual
     {
         /// <summary>

src/Avalonia.Base/Layout/Layoutable.cs

@@ -141,7 +141,6 @@ namespace Avalonia.Layout
         static Layoutable()
         {
             AffectsMeasure<Layoutable>(
-                IsVisibleProperty,
                 WidthProperty,
                 HeightProperty,
                 MinWidthProperty,
@@ -791,6 +790,25 @@ namespace Avalonia.Layout
         {
         }
 
+        protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+        {
+            base.OnPropertyChanged(change);
+
+            if (change.Property == IsVisibleProperty)
+            {
+                DesiredSize = default;
+
+                // All changes to visibility cause the parent element to be notified.
+                this.GetVisualParent<ILayoutable>()?.ChildDesiredSizeChanged(this);
+
+                // We only invalidate outselves when visibility is changed to true.
+                if (change.GetNewValue<bool>())
+                {
+                    InvalidateMeasure();
+                }
+            }
+        }
+
         /// <inheritdoc/>
         protected sealed override void OnVisualParentChanged(IVisual? oldParent, IVisual? newParent)
         {

src/Avalonia.Base/Layout/UniformGridLayout.cs

@@ -116,7 +116,7 @@ namespace Avalonia.Layout
         /// Defines the <see cref="MaximumRowsOrColumnsProperty"/> property.
         /// </summary>
         public static readonly StyledProperty<int> MaximumRowsOrColumnsProperty =
-            AvaloniaProperty.Register<UniformGridLayout, int>(nameof(MinItemWidth));
+            AvaloniaProperty.Register<UniformGridLayout, int>(nameof(MaximumRowsOrColumns));
 
         /// <summary>
         /// Defines the <see cref="Orientation"/> property.

src/Avalonia.Base/LogicalTree/ILogical.cs

@@ -1,12 +1,14 @@
 using System;
 using Avalonia.Collections;
 using Avalonia.Controls;
+using Avalonia.Metadata;
 
 namespace Avalonia.LogicalTree
 {
     /// <summary>
     /// Represents a node in the logical tree.
     /// </summary>
+    [NotClientImplementable]
     public interface ILogical
     {
         /// <summary>

src/Avalonia.Base/LogicalTree/ILogicalRoot.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.LogicalTree
+using Avalonia.Metadata;
+
+namespace Avalonia.LogicalTree
 {
     /// <summary>
     /// Represents a root of a logical tree.
     /// </summary>
+    [NotClientImplementable]
     public interface ILogicalRoot : ILogical
     {
     }

src/Avalonia.Base/Media/ConicGradientBrush.cs

@@ -11,7 +11,7 @@ namespace Avalonia.Media
         /// Defines the <see cref="Center"/> property.
         /// </summary>
         public static readonly StyledProperty<RelativePoint> CenterProperty =
-            AvaloniaProperty.Register<RadialGradientBrush, RelativePoint>(
+            AvaloniaProperty.Register<ConicGradientBrush, RelativePoint>(
                 nameof(Center),
                 RelativePoint.Center);
 
@@ -19,7 +19,7 @@ namespace Avalonia.Media
         /// Defines the <see cref="Angle"/> property.
         /// </summary>
         public static readonly StyledProperty<double> AngleProperty =
-            AvaloniaProperty.Register<RadialGradientBrush, double>(
+            AvaloniaProperty.Register<ConicGradientBrush, double>(
                 nameof(Angle),
                 0);
         

src/Avalonia.Base/Media/IBrush.cs

@@ -1,4 +1,5 @@
 using System.ComponentModel;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {
@@ -6,6 +7,7 @@ namespace Avalonia.Media
     /// Describes how an area is painted.
     /// </summary>
     [TypeConverter(typeof(BrushConverter))]
+    [NotClientImplementable]
     public interface IBrush
     {
         /// <summary>

src/Avalonia.Base/Media/IConicGradientBrush.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// Paints an area with a conic gradient.
     /// </summary>
+    [NotClientImplementable]
     public interface IConicGradientBrush : IGradientBrush
     {
         /// <summary>

src/Avalonia.Base/Media/IDashStyle.cs

@@ -1,10 +1,12 @@
 using System.Collections.Generic;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {
     /// <summary>
     /// Represents the sequence of dashes and gaps that will be applied by a <see cref="Pen"/>.
     /// </summary>
+    [NotClientImplementable]
     public interface IDashStyle
     {
         /// <summary>

src/Avalonia.Base/Media/IExperimentalAcrylicMaterial.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// Experimental Interface for producing Acrylic-like materials.
     /// </summary>
+    [NotClientImplementable]
     public interface IExperimentalAcrylicMaterial
     {
         /// <summary>

src/Avalonia.Base/Media/IGradientBrush.cs

@@ -1,10 +1,12 @@
 using System.Collections.Generic;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {
     /// <summary>
     /// A brush that draws with a gradient.
     /// </summary>
+    [NotClientImplementable]
     public interface IGradientBrush : IBrush
     {
         /// <summary>

src/Avalonia.Base/Media/IGradientStop.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// Describes the location and color of a transition point in a gradient.
     /// </summary>
+    [NotClientImplementable]
     public interface IGradientStop
     {
         /// <summary>

src/Avalonia.Base/Media/IImageBrush.cs

@@ -1,10 +1,12 @@
 using Avalonia.Media.Imaging;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {
     /// <summary>
     /// Paints an area with an <see cref="IBitmap"/>.
     /// </summary>
+    [NotClientImplementable]
     public interface IImageBrush : ITileBrush
     {
         /// <summary>
@@ -12,4 +14,4 @@ namespace Avalonia.Media
         /// </summary>
         IBitmap Source { get; }
     }
-}
+}

src/Avalonia.Base/Media/ILinearGradientBrush.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// A brush that draws with a linear gradient.
     /// </summary>
+    [NotClientImplementable]
     public interface ILinearGradientBrush : IGradientBrush
     {
         /// <summary>
@@ -15,4 +18,4 @@
         /// </summary>
         RelativePoint EndPoint { get; }
     }
-}
+}

src/Avalonia.Base/Media/IMutableBrush.cs

@@ -1,10 +1,12 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {
     /// <summary>
     /// Represents a mutable brush which can return an immutable clone of itself.
     /// </summary>
+    [NotClientImplementable]
     public interface IMutableBrush : IBrush, IAffectsRender
     {
         /// <summary>

src/Avalonia.Base/Media/IMutableExperimentalAcrylicMaterial.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// Represents a mutable brush which can return an immutable clone of itself.
     /// </summary>
+    [NotClientImplementable]
     public interface IMutableExperimentalAcrylicMaterial : IExperimentalAcrylicMaterial, IAffectsRender
     {
         /// <summary>

src/Avalonia.Base/Media/IMutableTransform.cs

@@ -1,4 +1,5 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {

src/Avalonia.Base/Media/IPen.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// Describes how a stroke is drawn.
     /// </summary>
+    [NotClientImplementable]
     public interface IPen
     {
         /// <summary>

src/Avalonia.Base/Media/IRadialGradientBrush.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// Paints an area with a radial gradient.
     /// </summary>
+    [NotClientImplementable]
     public interface IRadialGradientBrush : IGradientBrush
     {
         /// <summary>
@@ -21,4 +24,4 @@
         /// </summary>
         double Radius { get; }
     }
-}
+}

src/Avalonia.Base/Media/ISolidColorBrush.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Media
 {
     /// <summary>
     /// Fills an area with a solid color.
     /// </summary>
+    [NotClientImplementable]
     public interface ISolidColorBrush : IBrush
     {
         /// <summary>
@@ -10,4 +13,4 @@ namespace Avalonia.Media
         /// </summary>
         Color Color { get; }
     }
-}
+}

src/Avalonia.Base/Media/ITileBrush.cs

@@ -1,10 +1,12 @@
 using Avalonia.Media.Imaging;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
-{  
+{
     /// <summary>
     /// A brush which displays a repeating image.
     /// </summary>
+    [NotClientImplementable]
     public interface ITileBrush : IBrush
     {
         /// <summary>

src/Avalonia.Base/Media/IVisualBrush.cs

@@ -1,10 +1,12 @@
-using Avalonia.VisualTree;
+using Avalonia.Metadata;
+using Avalonia.VisualTree;
 
 namespace Avalonia.Media
 {
     /// <summary>
     /// Paints an area with an <see cref="IVisual"/>.
     /// </summary>
+    [NotClientImplementable]
     public interface IVisualBrush : ITileBrush
     {
         /// <summary>
@@ -12,4 +14,4 @@ namespace Avalonia.Media
         /// </summary>
         IVisual Visual { get; }
     }
-}
+}

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

@@ -1,5 +1,6 @@
 using System;
 using System.IO;
+using Avalonia.Metadata;
 using Avalonia.Platform;
 using Avalonia.Utilities;
 
@@ -8,6 +9,7 @@ namespace Avalonia.Media.Imaging
     /// <summary>
     /// Represents a bitmap image.
     /// </summary>
+    [NotClientImplementable]
     public interface IBitmap : IImage, IDisposable
     {
         /// <summary>

src/Avalonia.Base/Media/TextFormatting/ITextSource.cs

@@ -1,4 +1,6 @@
-namespace Avalonia.Media.TextFormatting
+using Avalonia.Metadata;
+
+namespace Avalonia.Media.TextFormatting
 {
     /// <summary>
     /// Produces <see cref="TextRun"/> objects that are used by the <see cref="TextFormatter"/>.

src/Avalonia.Base/Metadata/NotClientImplementableAttribute.cs

@@ -0,0 +1,17 @@
+using System;
+
+namespace Avalonia.Metadata
+{
+    /// <summary>
+    /// This interface is not intended to be implemented outside of the core Avalonia framework as
+    /// its API may change without warning.
+    /// </summary>
+    /// <remarks>
+    /// This interface is stable for consumption by a client, but should not be implemented as members
+    /// may be added to its API.
+    /// </remarks>
+    [AttributeUsage(AttributeTargets.Interface)]
+    public class NotClientImplementableAttribute : Attribute
+    {
+    }
+}

src/Avalonia.Base/Metadata/UnstableAttribute.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace Avalonia.Metadata
+{
+    /// <summary>
+    /// This API is unstable and is not covered by API compatibility guarantees between minor and
+    /// patch releases.
+    /// </summary>
+    public class UnstableAttribute : Attribute
+    {
+    }
+}

src/Avalonia.Base/Platform/IAssetLoader.cs

@@ -2,12 +2,14 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Reflection;
+using Avalonia.Metadata;
 
 namespace Avalonia.Platform
 {
     /// <summary>
     /// Loads assets compiled into the application binary.
     /// </summary>
+    [Unstable]
     public interface IAssetLoader
     {
         /// <summary>

src/Avalonia.Base/Platform/IBitmapImpl.cs

@@ -1,11 +1,13 @@
 using System;
 using System.IO;
+using Avalonia.Metadata;
 
 namespace Avalonia.Platform
 {
     /// <summary>
     /// Defines the platform-specific interface for a <see cref="Avalonia.Media.Imaging.Bitmap"/>.
     /// </summary>
+    [Unstable]
     public interface IBitmapImpl : IDisposable
     {
         /// <summary>

src/Avalonia.Base/Platform/ICursorImpl.cs

@@ -1,5 +1,6 @@
 using System;
 using Avalonia.Input;
+using Avalonia.Metadata;
 
 #nullable enable
 
@@ -8,6 +9,7 @@ namespace Avalonia.Platform
     /// <summary>
     /// Represents a platform implementation of a <see cref="Cursor"/>.
     /// </summary>
+    [Unstable]
     public interface ICursorImpl : IDisposable
     {
     }

src/Avalonia.Base/Platform/IDrawingContextImpl.cs

@@ -3,12 +3,14 @@ using Avalonia.Media;
 using Avalonia.Rendering.SceneGraph;
 using Avalonia.Utilities;
 using Avalonia.Media.Imaging;
+using Avalonia.Metadata;
 
 namespace Avalonia.Platform
 {
     /// <summary>
     /// Defines the interface through which drawing occurs.
     /// </summary>
+    [Unstable]
     public interface IDrawingContextImpl : IDisposable
     {
         /// <summary>

src/Avalonia.Base/Platform/IFontManagerImpl.cs

@@ -1,9 +1,11 @@
 using System.Collections.Generic;
 using System.Globalization;
 using Avalonia.Media;
+using Avalonia.Metadata;
 
 namespace Avalonia.Platform
 {
+    [Unstable]
     public interface IFontManagerImpl
     {
         /// <summary>

src/Avalonia.Base/Platform/IGeometryImpl.cs

@@ -1,10 +1,12 @@
 using Avalonia.Media;
+using Avalonia.Metadata;
 
 namespace Avalonia.Platform
 {
     /// <summary>
     /// Defines the platform-specific interface for a <see cref="Geometry"/>.
     /// </summary>
+    [Unstable]
     public interface IGeometryImpl
     {
         /// <summary>

src/Avalonia.Base/Platform/IGlyphRunImpl.cs

@@ -1,9 +1,11 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Platform
 {
     /// <summary>
     ///     Actual implementation of a glyph run that stores platform dependent resources.
     /// </summary>
+    [Unstable]
     public interface IGlyphRunImpl : IDisposable { }
 }

src/Avalonia.Base/Platform/IGlyphTypefaceImpl.cs

@@ -1,7 +1,9 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Platform
 {
+    [Unstable]
     public interface IGlyphTypefaceImpl : IDisposable
     {
         /// <summary>

src/Avalonia.Base/Platform/IMacOSTopLevelPlatformHandle.cs

@@ -1,7 +1,9 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Platform
 {
+    [Unstable]
     public interface IMacOSTopLevelPlatformHandle
     {
         IntPtr NSView { get; }

src/Avalonia.Base/Platform/IPlatformRenderInterface.cs

@@ -3,12 +3,14 @@ using System.Collections.Generic;
 using System.IO;
 using Avalonia.Media;
 using Avalonia.Media.Imaging;
+using Avalonia.Metadata;
 
 namespace Avalonia.Platform
 {
     /// <summary>
     /// Defines the main platform-specific interface for the rendering subsystem.
     /// </summary>
+    [Unstable]
     public interface IPlatformRenderInterface
     {
         /// <summary>

src/Avalonia.Base/Platform/IPlatformSettings.cs

@@ -1,7 +1,9 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Platform
 {
+    [Unstable]
     public interface IPlatformSettings
     {
         Size DoubleClickSize { get; }