Merge pull request #707 from jkoritzinsky/Updated-PlatformDetect-and-Modules

Implemented extensibility system for Avalonia

src/Avalonia.Controls/AppBuilderBase.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Reflection;
+using System.Linq;
 using Avalonia.Platform;
 
 namespace Avalonia.Controls
@@ -21,33 +22,48 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets a method to call the initialize the runtime platform services (e. g. AssetLoader)
         /// </summary>
-        public Action RuntimePlatformServices { get; set; }
+        public Action RuntimePlatformServicesInitializer { get; private set; }
 
         /// <summary>
         /// Gets or sets the <see cref="Application"/> instance being initialized.
         /// </summary>
-        public Application Instance { get; set; }
+        public Application Instance { get; protected set; }
 
         /// <summary>
         /// Gets or sets a method to call the initialize the windowing subsystem.
         /// </summary>
-        public Action WindowingSubsystem { get; set; }
+        public Action WindowingSubsystemInitializer { get; private set; }
+
+        /// <summary>
+        /// Gets the name of the currently selected windowing subsystem.
+        /// </summary>
+        public string WindowingSubsystemName { get; private set; }
 
         /// <summary>
         /// Gets or sets a method to call the initialize the windowing subsystem.
         /// </summary>
-        public Action RenderingSubsystem { get; set; }
+        public Action RenderingSubsystemInitializer { get; private set; }
+
+        /// <summary>
+        /// Gets the name of the currently selected rendering subsystem.
+        /// </summary>
+        public string RenderingSubsystemName { get; private set; }
+
+        /// <summary>
+        /// Gets or sets a method to call after the <see cref="Application"/> is setup.
+        /// </summary>
+        public Action<TAppBuilder> AfterSetupCallback { get; private set; } = builder => { };
 
         /// <summary>
         /// Gets or sets a method to call before <see cref="Start{TMainWindow}"/> is called on the
         /// <see cref="Application"/>.
         /// </summary>
-        public Action<TAppBuilder> BeforeStartCallback { get; set; }
+        public Action<TAppBuilder> BeforeStartCallback { get; private set; } = builder => { };
 
         protected AppBuilderBase(IRuntimePlatform platform, Action platformSevices)
         {
             RuntimePlatform = platform;
-            RuntimePlatformServices = platformSevices;
+            RuntimePlatformServicesInitializer = platformSevices;
         }
 
         /// <summary>
@@ -85,7 +101,13 @@ namespace Avalonia.Controls
         /// <returns>An <typeparamref name="TAppBuilder"/> instance.</returns>
         public TAppBuilder BeforeStarting(Action<TAppBuilder> callback)
         {
-            BeforeStartCallback = callback;
+            BeforeStartCallback = (Action<TAppBuilder>)Delegate.Combine(BeforeStartCallback, callback);
+            return Self;
+        }
+
+        public TAppBuilder AfterSetup(Action<TAppBuilder> callback)
+        {
+            AfterSetupCallback = (Action<TAppBuilder>)Delegate.Combine(AfterSetupCallback, callback);
             return Self;
         }
 
@@ -97,7 +119,7 @@ namespace Avalonia.Controls
             where TMainWindow : Window, new()
         {
             Setup();
-            BeforeStartCallback?.Invoke(Self);
+            BeforeStartCallback(Self);
 
             var window = new TMainWindow();
             window.Show();
@@ -119,9 +141,10 @@ namespace Avalonia.Controls
         /// </summary>
         /// <param name="initializer">The method to call to initialize the windowing subsystem.</param>
         /// <returns>An <typeparamref name="TAppBuilder"/> instance.</returns>
-        public TAppBuilder UseWindowingSubsystem(Action initializer)
+        public TAppBuilder UseWindowingSubsystem(Action initializer, string name = "")
         {
-            WindowingSubsystem = initializer;
+            WindowingSubsystemInitializer = initializer;
+            WindowingSubsystemName = name;
             return Self;
         }
 
@@ -130,16 +153,17 @@ namespace Avalonia.Controls
         /// </summary>
         /// <param name="dll">The dll in which to look for subsystem.</param>
         /// <returns>An <typeparamref name="TAppBuilder"/> instance.</returns>
-        public TAppBuilder UseWindowingSubsystem(string dll) => UseWindowingSubsystem(GetInitializer(dll));
+        public TAppBuilder UseWindowingSubsystem(string dll) => UseWindowingSubsystem(GetInitializer(dll), dll.Replace("Avalonia.", string.Empty));
 
         /// <summary>
         /// Specifies a rendering subsystem to use.
         /// </summary>
         /// <param name="initializer">The method to call to initialize the rendering subsystem.</param>
         /// <returns>An <typeparamref name="TAppBuilder"/> instance.</returns>
-        public TAppBuilder UseRenderingSubsystem(Action initializer)
+        public TAppBuilder UseRenderingSubsystem(Action initializer, string name = "")
         {
-            RenderingSubsystem = initializer;
+            RenderingSubsystemInitializer = initializer;
+            RenderingSubsystemName = name;
             return Self;
         }
 
@@ -160,6 +184,28 @@ namespace Avalonia.Controls
             init.Invoke(null, null);
         };
 
+        public TAppBuilder UseAvaloniaModules() => AfterSetup(builder => SetupAvaloniaModules());
+
+        private void SetupAvaloniaModules()
+        {
+            var moduleInitializers = from assembly in AvaloniaLocator.Current.GetService<IRuntimePlatform>().GetLoadedAssemblies()
+                                          from attribute in assembly.GetCustomAttributes<ExportAvaloniaModuleAttribute>()
+                                          where attribute.ForWindowingSubsystem == ""
+                                           || attribute.ForWindowingSubsystem == WindowingSubsystemName
+                                          where attribute.ForRenderingSubsystem == ""
+                                           || attribute.ForRenderingSubsystem == RenderingSubsystemName
+                                          group attribute by attribute.Name into exports
+                                          select (from export in exports
+                                                  orderby export.ForWindowingSubsystem.Length descending
+                                                  orderby export.ForRenderingSubsystem.Length descending
+                                                  select export).First().ModuleType into moduleType
+                                          select (from constructor in moduleType.GetTypeInfo().DeclaredConstructors
+                                                  where constructor.GetParameters().Length == 0 && !constructor.IsStatic
+                                                  select constructor).Single() into constructor
+                                          select (Action)(() => constructor.Invoke(new object[0]));
+            Delegate.Combine(moduleInitializers.ToArray()).DynamicInvoke();
+        }
+
         /// <summary>
         /// Sets up the platform-speciic services for the <see cref="Application"/>.
         /// </summary>
@@ -170,26 +216,27 @@ namespace Avalonia.Controls
                 throw new InvalidOperationException("No App instance configured.");
             }
 
-            if (RuntimePlatformServices == null)
+            if (RuntimePlatformServicesInitializer == null)
             {
                 throw new InvalidOperationException("No runtime platform services configured.");
             }
 
-            if (WindowingSubsystem == null)
+            if (WindowingSubsystemInitializer == null)
             {
                 throw new InvalidOperationException("No windowing system configured.");
             }
 
-            if (RenderingSubsystem == null)
+            if (RenderingSubsystemInitializer == null)
             {
                 throw new InvalidOperationException("No rendering system configured.");
             }
 
             Instance.RegisterServices();
-            RuntimePlatformServices();
-            WindowingSubsystem();
-            RenderingSubsystem();
+            RuntimePlatformServicesInitializer();
+            WindowingSubsystemInitializer();
+            RenderingSubsystemInitializer();
             Instance.Initialize();
+            AfterSetupCallback(Self);
         }
     }
 }

src/Avalonia.Controls/Avalonia.Controls.csproj

@@ -59,6 +59,8 @@
     <Compile Include="PointEventArgs.cs" />
     <Compile Include="Embedding\EmbeddableControlRoot.cs" />
     <Compile Include="Platform\IEmbeddableWindowImpl.cs" />
+    <Compile Include="Platform\ExportAvaloniaModuleAttribute.cs" />
+    <Compile Include="Platform\ExportWindowingSubsystemAttribute.cs" />
     <Compile Include="WindowIcon.cs" />
     <Compile Include="IPseudoClasses.cs" />
     <Compile Include="DropDownItem.cs" />

src/Avalonia.Controls/Platform/ExportAvaloniaModuleAttribute.cs

@@ -0,0 +1,58 @@
+using System;
+
+namespace Avalonia.Platform
+{
+    /// <summary>
+    /// Defines an "Avalonia Module", a 3rd party extension to Avalonia that can be automatically initialized by an AppBuilder instance.
+    /// </summary>
+    /// <remarks>
+    /// Avalonia Modules can either be platform independent (ex default control styles provider) or dependent on a
+    /// specific windowing or rendering subsystem being used (ex native rendering speedup, subsystem-specific interop backends).
+    /// In the case of a subsystem-specific module, you can specify multiple module implementations, and also a fallback
+    /// platform-independent module if you so choose. Additionally, these different implementations can be in different assemblies.
+    /// They just need to all share the same module name.
+    /// 
+    /// For example, if I had a module Foo that has a special back-end for Skia and a less performant/less user friendly back-end for
+    /// any other rendering subsystem, I would do the following:
+    /// <code>
+    /// // In assembly FooModuleSkia.dll
+    /// [assembly:ExportAvaloniaModule("Foo", typeof(FooModuleSkia), ForRenderingSubsystem="Skia")]
+    /// 
+    /// class FooModuleSkia
+    /// {
+    ///     public FooModuleSkia()
+    ///     {
+    ///         InitializeModule();
+    ///     }
+    /// }
+    /// 
+    /// // In assembly FooModuleFallback.dll
+    /// [assembly:ExportAvaloniaModule("Foo", typeof(FooModuleFallback))]
+    /// 
+    /// class FooModuleFallback
+    /// {
+    ///     public FooModuleFallback()
+    ///     {
+    ///         InitializeModule();
+    ///     }
+    /// }
+    /// 
+    /// </code>
+    /// The fallback module will only be initialized if the Skia-specific module is not applicable.
+    /// </remarks>
+    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true)]
+    public class ExportAvaloniaModuleAttribute : Attribute
+    {
+        public ExportAvaloniaModuleAttribute(string name, Type moduleType)
+        {
+            Name = name;
+            ModuleType = moduleType;
+        }
+
+        public string Name { get; private set; }
+        public Type ModuleType { get; private set; }
+
+        public string ForWindowingSubsystem { get; set; } = "";
+        public string ForRenderingSubsystem { get; set; } = "";
+    }
+}

src/Avalonia.Controls/Platform/ExportWindowingSubsystemAttribute.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Avalonia.Platform
+{
+    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true)]
+    public class ExportWindowingSubsystemAttribute : Attribute
+    {
+        public ExportWindowingSubsystemAttribute(OperatingSystemType requiredRuntimePlatform, int priority, string name, Type initializationType, string initializationMethod)
+        {
+            Name = name;
+            InitializationType = initializationType;
+            InitializationMethod = initializationMethod;
+            RequiredOS = requiredRuntimePlatform;
+            Priority = priority;
+        }
+
+        public string InitializationMethod { get; private set; }
+        public Type InitializationType { get; private set; }
+        public string Name { get; private set; }
+        public int Priority { get; private set; }
+        public OperatingSystemType RequiredOS { get; private set; }
+    }
+}

src/Avalonia.DotNetFrameworkRuntime/AppBuilder.cs

@@ -7,6 +7,7 @@ using System.Threading.Tasks;
 using Avalonia.Controls;
 using Avalonia.Platform;
 using Avalonia.Shared.PlatformSupport;
+using System.IO;
 
 namespace Avalonia
 {
@@ -23,18 +24,47 @@ namespace Avalonia
 
         public AppBuilder UsePlatformDetect()
         {
-            var platformId = (int)Environment.OSVersion.Platform;
-            if (platformId == 4 || platformId == 6)
-            {
-                UseRenderingSubsystem("Avalonia.Cairo");
-                UseWindowingSubsystem("Avalonia.Gtk");
-            }
-            else
+            var os = RuntimePlatform.GetRuntimeInfo().OperatingSystem;
+
+            LoadAssembliesInDirectory();
+
+            var windowingSubsystemAttribute = (from assembly in RuntimePlatform.GetLoadedAssemblies()
+                                               from attribute in assembly.GetCustomAttributes<ExportWindowingSubsystemAttribute>()
+                                               where attribute.RequiredOS == os
+                                               orderby attribute.Priority ascending
+                                               select attribute).First();
+
+            var renderingSubsystemAttribute = (from assembly in RuntimePlatform.GetLoadedAssemblies()
+                                               from attribute in assembly.GetCustomAttributes<ExportRenderingSubsystemAttribute>()
+                                               where attribute.RequiredOS == os
+                                               where attribute.RequiresWindowingSubsystem == null
+                                                || attribute.RequiresWindowingSubsystem == windowingSubsystemAttribute.Name
+                                               orderby attribute.Priority ascending
+                                               select attribute).First();
+
+            UseWindowingSubsystem(() => windowingSubsystemAttribute.InitializationType
+                .GetRuntimeMethod(windowingSubsystemAttribute.InitializationMethod, Type.EmptyTypes).Invoke(null, null),
+                windowingSubsystemAttribute.Name);
+
+            UseRenderingSubsystem(() => renderingSubsystemAttribute.InitializationType
+                .GetRuntimeMethod(renderingSubsystemAttribute.InitializationMethod, Type.EmptyTypes).Invoke(null, null),
+                renderingSubsystemAttribute.Name);
+            
+            return this;
+        }
+
+        private void LoadAssembliesInDirectory()
+        {
+            foreach (var file in new FileInfo(Assembly.GetEntryAssembly().Location).Directory.EnumerateFiles("*.dll"))
             {
-                UseRenderingSubsystem("Avalonia.Direct2D1");
-                UseWindowingSubsystem("Avalonia.Win32");
+                try
+                {
+                    Assembly.LoadFile(file.FullName);
+                }
+                catch (Exception)
+                {
+                }
             }
-            return this;
         }
     }
 }

src/Avalonia.DotNetFrameworkRuntime/Avalonia.DotNetFrameworkRuntime.csproj

@@ -64,6 +64,10 @@
       <Project>{D2221C82-4A25-4583-9B43-D791E3F6820C}</Project>
       <Name>Avalonia.Controls</Name>
     </ProjectReference>
+    <ProjectReference Include="..\Avalonia.SceneGraph\Avalonia.SceneGraph.csproj">
+      <Project>{eb582467-6abb-43a1-b052-e981ba910e3a}</Project>
+      <Name>Avalonia.SceneGraph</Name>
+    </ProjectReference>
     <ProjectReference Include="..\Avalonia.Styling\Avalonia.Styling.csproj">
       <Project>{f1baa01a-f176-4c6a-b39d-5b40bb1b148f}</Project>
       <Name>Avalonia.Styling</Name>
@@ -81,4 +85,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>

src/Avalonia.SceneGraph/Avalonia.SceneGraph.csproj

@@ -100,6 +100,7 @@
     <Compile Include="Media\FormattedText.cs" />
     <Compile Include="Media\Geometry.cs" />
     <Compile Include="Media\IDrawingContext.cs" />
+    <Compile Include="Platform\ExportRenderingSubsystemAttribute.cs" />
     <Compile Include="RenderTargetCorruptedException.cs" />
     <Compile Include="VisualTree\IVisual.cs" />
     <Compile Include="Media\Imaging\Bitmap.cs" />

src/Avalonia.SceneGraph/Platform/ExportRenderingSubsystemAttribute.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Avalonia.Platform
+{
+    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true)]
+    public class ExportRenderingSubsystemAttribute : Attribute
+    {
+        public ExportRenderingSubsystemAttribute(OperatingSystemType requiredOS, int priority, string name, Type initializationType, string initializationMethod)
+        {
+            Name = name;
+            InitializationType = initializationType;
+            InitializationMethod = initializationMethod;
+            RequiredOS = requiredOS;
+            Priority = priority;
+        }
+
+        public string InitializationMethod { get; private set; }
+        public Type InitializationType { get; private set; }
+        public string Name { get; private set; }
+        public int Priority { get; private set; }
+        public OperatingSystemType RequiredOS { get; private set; }
+        public string RequiresWindowingSubsystem { get; set; }
+    }
+}

src/Gtk/Avalonia.Cairo/CairoPlatform.cs

@@ -14,7 +14,7 @@ namespace Avalonia
     {
         public static T UseCairo<T>(this T builder) where T : AppBuilderBase<T>, new()
         {
-            builder.RenderingSubsystem = Avalonia.Cairo.CairoPlatform.Initialize;
+            builder.UseRenderingSubsystem(Cairo.CairoPlatform.Initialize, "Cairo");
             return builder;
         }
     }

src/Gtk/Avalonia.Cairo/Properties/AssemblyInfo.cs

@@ -1,6 +1,8 @@
 // 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 Avalonia.Cairo;
+using Avalonia.Platform;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
@@ -37,3 +39,7 @@ using System.Runtime.InteropServices;
 // [assembly: AssemblyVersion("1.0.*")]
 [assembly: AssemblyVersion("1.0.0.0")]
 [assembly: AssemblyFileVersion("1.0.0.0")]
+
+[assembly: ExportRenderingSubsystem(OperatingSystemType.WinNT, 2, "Cairo", typeof(CairoPlatform), nameof(CairoPlatform.Initialize), RequiresWindowingSubsystem = "GTK")]
+[assembly: ExportRenderingSubsystem(OperatingSystemType.Linux, 1, "Cairo", typeof(CairoPlatform), nameof(CairoPlatform.Initialize), RequiresWindowingSubsystem = "GTK")]
+[assembly: ExportRenderingSubsystem(OperatingSystemType.OSX, 2, "Cairo", typeof(CairoPlatform), nameof(CairoPlatform.Initialize), RequiresWindowingSubsystem = "GTK")]

src/Gtk/Avalonia.Gtk/GtkPlatform.cs

@@ -16,7 +16,7 @@ namespace Avalonia
     {
         public static T UseGtk<T>(this T builder) where T : AppBuilderBase<T>, new()
         {
-            builder.WindowingSubsystem = Avalonia.Gtk.GtkPlatform.Initialize;
+            builder.UseWindowingSubsystem(Gtk.GtkPlatform.Initialize, "Gtk");
             return builder;
         }
     }

src/Gtk/Avalonia.Gtk/Properties/AssemblyInfo.cs

@@ -1,6 +1,8 @@
 // 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 Avalonia.Gtk;
+using Avalonia.Platform;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 
@@ -19,3 +21,8 @@ using System.Runtime.CompilerServices;
 // The form "{Major}.{Minor}.*" will automatically update the build and revision,
 // and "{Major}.{Minor}.{Build}.*" will update just the revision.
 [assembly: AssemblyVersion("1.0.*")]
+
+[assembly: ExportWindowingSubsystem(OperatingSystemType.WinNT, 2, "GTK", typeof(GtkPlatform), nameof(GtkPlatform.Initialize))]
+[assembly: ExportWindowingSubsystem(OperatingSystemType.Linux, 1, "GTK", typeof(GtkPlatform), nameof(GtkPlatform.Initialize))]
+[assembly: ExportWindowingSubsystem(OperatingSystemType.OSX, 2, "GTK", typeof(GtkPlatform), nameof(GtkPlatform.Initialize))]
+

src/Skia/Avalonia.Skia.Desktop/Properties/AssemblyInfo.cs

@@ -1,3 +1,5 @@
+using Avalonia.Platform;
+using Avalonia.Skia;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
@@ -34,3 +36,5 @@ using System.Runtime.InteropServices;
 // [assembly: AssemblyVersion("1.0.*")]
 [assembly: AssemblyVersion("1.0.0.0")]
 [assembly: AssemblyFileVersion("1.0.0.0")]
+
+[assembly: ExportRenderingSubsystem(OperatingSystemType.WinNT, 3, "Skia", typeof(SkiaPlatform), nameof(SkiaPlatform.Initialize))]

src/Skia/Avalonia.Skia/SkiaPlatform.cs

@@ -10,7 +10,7 @@ namespace Avalonia
     {
         public static T UseSkia<T>(this T builder) where T : AppBuilderBase<T>, new()
         {
-            builder.RenderingSubsystem = Avalonia.Skia.SkiaPlatform.Initialize;
+            builder.UseRenderingSubsystem(Skia.SkiaPlatform.Initialize, "Skia");
             return builder;
         }
     }

src/Windows/Avalonia.Direct2D1/Direct2D1Platform.cs

@@ -14,7 +14,7 @@ namespace Avalonia
     {
         public static T UseDirect2D1<T>(this T builder) where T : AppBuilderBase<T>, new()
         {
-            builder.RenderingSubsystem = Avalonia.Direct2D1.Direct2D1Platform.Initialize;
+            builder.UseRenderingSubsystem(Direct2D1.Direct2D1Platform.Initialize, "Direct2D1");
             return builder;
         }
     }

src/Windows/Avalonia.Direct2D1/Properties/AssemblyInfo.cs

@@ -2,5 +2,9 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System.Reflection;
+using Avalonia.Platform;
+using Avalonia.Direct2D1;
 
 [assembly: AssemblyTitle("Avalonia.Direct2D1")]
+[assembly: ExportRenderingSubsystem(OperatingSystemType.WinNT, 1, "Direct2D1", typeof(Direct2D1Platform), nameof(Direct2D1Platform.Initialize))]
+

src/Windows/Avalonia.Win32/Properties/AssemblyInfo.cs

@@ -1,6 +1,9 @@
 // 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 Avalonia.Platform;
+using Avalonia.Win32;
 using System.Reflection;
 
 [assembly: AssemblyTitle("Avalonia.Win32")]
+[assembly: ExportWindowingSubsystem(OperatingSystemType.WinNT, 1, "Win32", typeof(Win32Platform), nameof(Win32Platform.Initialize))]

src/Windows/Avalonia.Win32/Win32Platform.cs

@@ -23,7 +23,7 @@ namespace Avalonia
     {
         public static T UseWin32<T>(this T builder) where T : AppBuilderBase<T>, new()
         {
-            builder.WindowingSubsystem = Avalonia.Win32.Win32Platform.Initialize;
+            builder.UseWindowingSubsystem(Win32.Win32Platform.Initialize, "Win32");
             return builder;
         }
     }

src/iOS/Avalonia.iOS/iOSPlatform.cs

@@ -15,7 +15,7 @@ namespace Avalonia
     {
         public static T UseiOS<T>(this T builder) where T : AppBuilderBase<T>, new()
         {
-            builder.WindowingSubsystem = Avalonia.iOS.iOSPlatform.Initialize;
+            builder.UseWindowingSubsystem(iOSPlatform.Initialize, "iOS");
             return builder;
         }
 

tests/Avalonia.Controls.UnitTests/AppBuilderTests.cs

@@ -0,0 +1,126 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+using Avalonia.Controls.UnitTests;
+using Avalonia.Platform;
+
+[assembly: ExportAvaloniaModule("DefaultModule", typeof(AppBuilderTests.DefaultModule))]
+[assembly: ExportAvaloniaModule("RenderingModule", typeof(AppBuilderTests.Direct2DModule), ForRenderingSubsystem = "Direct2D1")]
+[assembly: ExportAvaloniaModule("RenderingModule", typeof(AppBuilderTests.SkiaModule), ForRenderingSubsystem = "Skia")]
+[assembly: ExportAvaloniaModule("RenderingModule", typeof(AppBuilderTests.DefaultRenderingModule))]
+
+
+namespace Avalonia.Controls.UnitTests
+{
+
+    public class AppBuilderTests
+    {
+        class App : Application
+        {
+        }
+
+        public class DefaultModule
+        {
+            public static bool IsLoaded = false;
+            public DefaultModule()
+            {
+                IsLoaded = true;
+            }
+        }
+
+        public class DefaultRenderingModule
+        {
+            public static bool IsLoaded = false;
+            public DefaultRenderingModule()
+            {
+                IsLoaded = true;
+            }
+        }
+
+        public class Direct2DModule
+        {
+            public static bool IsLoaded = false;
+            public Direct2DModule()
+            {
+                IsLoaded = true;
+            }
+        }
+
+        public class SkiaModule
+        {
+            public static bool IsLoaded = false;
+            public SkiaModule()
+            {
+                IsLoaded = true;
+            }
+        }
+        
+        [Fact]
+        public void LoadsDefaultModule()
+        {
+            using (AvaloniaLocator.EnterScope())
+            {
+                ResetModuleLoadStates();
+                AppBuilder.Configure<App>()
+                    .UseWindowingSubsystem(() => { })
+                    .UseRenderingSubsystem(() => { })
+                    .UseAvaloniaModules()
+                    .SetupWithoutStarting();
+
+                Assert.True(DefaultModule.IsLoaded); 
+            }
+        }
+
+        [Fact]
+        public void LoadsRenderingModuleWithMatchingRenderingSubsystem()
+        {
+            using (AvaloniaLocator.EnterScope())
+            {
+                ResetModuleLoadStates();
+                var builder = AppBuilder.Configure<App>()
+                    .UseWindowingSubsystem(() => { })
+                    .UseRenderingSubsystem(() => { }, "Direct2D1");
+                builder.UseAvaloniaModules().SetupWithoutStarting();
+                Assert.False(DefaultRenderingModule.IsLoaded);
+                Assert.True(Direct2DModule.IsLoaded);
+                Assert.False(SkiaModule.IsLoaded);
+
+                ResetModuleLoadStates();
+                builder = AppBuilder.Configure<App>()
+                    .UseWindowingSubsystem(() => { })
+                    .UseRenderingSubsystem(() => { }, "Skia");
+                builder.UseAvaloniaModules().SetupWithoutStarting();
+                Assert.False(DefaultRenderingModule.IsLoaded);
+                Assert.False(Direct2DModule.IsLoaded);
+                Assert.True(SkiaModule.IsLoaded); 
+            }
+        }
+
+        [Fact]
+        public void LoadsRenderingModuleWithoutDependenciesWhenNoModuleMatches()
+        {
+            using (AvaloniaLocator.EnterScope())
+            {
+                ResetModuleLoadStates();
+                var builder = AppBuilder.Configure<App>()
+                    .UseWindowingSubsystem(() => { })
+                    .UseRenderingSubsystem(() => { }, "Cairo");
+                builder.UseAvaloniaModules().SetupWithoutStarting();
+                Assert.True(DefaultRenderingModule.IsLoaded);
+                Assert.False(Direct2DModule.IsLoaded);
+                Assert.False(SkiaModule.IsLoaded); 
+            }
+        }
+
+        private static void ResetModuleLoadStates()
+        {
+            DefaultModule.IsLoaded = false;
+            DefaultRenderingModule.IsLoaded = false;
+            Direct2DModule.IsLoaded = false;
+            SkiaModule.IsLoaded = false;
+        }
+    }
+}

tests/Avalonia.Controls.UnitTests/Avalonia.Controls.UnitTests.csproj

@@ -94,6 +94,7 @@
     <Otherwise />
   </Choose>
   <ItemGroup>
+    <Compile Include="AppBuilderTests.cs" />
     <Compile Include="ClassesTests.cs" />
     <Compile Include="LayoutTransformControlTests.cs" />
     <Compile Include="Presenters\ItemsPresenterTests_Virtualization_Simple.cs" />
@@ -152,6 +153,10 @@
     <Compile Include="WrapPanelTests.cs" />
   </ItemGroup>
   <ItemGroup>
+    <ProjectReference Include="..\..\src\Avalonia.DotNetFrameworkRuntime\Avalonia.DotNetFrameworkRuntime.csproj">
+      <Project>{4a1abb09-9047-4bd5-a4ad-a055e52c5ee0}</Project>
+      <Name>Avalonia.DotNetFrameworkRuntime</Name>
+    </ProjectReference>
     <ProjectReference Include="..\..\src\Markup\Avalonia.Markup.Xaml\Avalonia.Markup.Xaml.csproj">
       <Project>{3e53a01a-b331-47f3-b828-4a5717e77a24}</Project>
       <Name>Avalonia.Markup.Xaml</Name>

tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs

@@ -267,12 +267,16 @@ namespace Avalonia.Controls.UnitTests.Primitives
             var globalStyles = new Mock<IGlobalStyles>();
             globalStyles.Setup(x => x.Styles).Returns(styles);
 
+            var renderInterface = new Mock<IPlatformRenderInterface>();
+            renderInterface.Setup(x => x.CreateRenderer(It.IsAny<IPlatformHandle>())).Returns(() => new Mock<IRenderTarget>().Object);
+
             AvaloniaLocator.CurrentMutable
                 .Bind<ILayoutManager>().ToTransient<LayoutManager>()
                 .Bind<IGlobalStyles>().ToFunc(() => globalStyles.Object)
                 .Bind<IWindowingPlatform>().ToConstant(new WindowingPlatformMock())
-                .Bind<IStyler>().ToTransient<Styler>();
-
+                .Bind<IStyler>().ToTransient<Styler>()
+                .Bind<IPlatformRenderInterface>().ToFunc(() => renderInterface.Object);
+            
             return result;
         }
 

tests/Avalonia.UnitTests/TestServices.cs

@@ -152,7 +152,8 @@ namespace Avalonia.UnitTests
                     It.IsAny<FontWeight>(),
                     It.IsAny<TextWrapping>()) == Mock.Of<IFormattedTextImpl>() &&
                 x.CreateStreamGeometry() == Mock.Of<IStreamGeometryImpl>(
-                    y => y.Open() == Mock.Of<IStreamGeometryContextImpl>()));
+                    y => y.Open() == Mock.Of<IStreamGeometryContextImpl>()) &&
+                x.CreateRenderer(It.IsAny<IPlatformHandle>()) == Mock.Of<IRenderTarget>());
         }
     }
 }