Merge branch 'master' of github.com:AvaloniaUI/Avalonia into dev/siegfriedpammer/event-viewer

samples/ControlCatalog/App.xaml

@@ -14,6 +14,11 @@
       <Setter Property="FontSize" Value="13"/>
     </Style>
 
-    <StyleInclude Source="resm:ControlCatalog.SideBar.xaml"/>
+      <Style Selector="TextBlock.h3">
+          <Setter Property="Foreground" Value="#a2a2a2"/>
+          <Setter Property="FontSize" Value="13"/>
+      </Style>
+
+      <StyleInclude Source="resm:ControlCatalog.SideBar.xaml"/>
   </Application.Styles>
-</Application>
+</Application>

samples/ControlCatalog/ControlCatalog.csproj

@@ -35,4 +35,4 @@
   </ItemGroup>
   
   <Import Project="..\..\build\Serilog.props" />
-</Project>
+</Project>

samples/ControlCatalog/MainView.xaml

@@ -20,8 +20,9 @@
     <TabItem Header="Expander"><pages:ExpanderPage/></TabItem>
     <TabItem Header="Image"><pages:ImagePage/></TabItem>
     <TabItem Header="LayoutTransformControl"><pages:LayoutTransformControlPage/></TabItem>
+    <TabItem Header="ListBox"><pages:ListBoxPage/></TabItem>
     <TabItem Header="Menu"><pages:MenuPage/></TabItem>
-	  <TabItem Header="NumericUpDown"><pages:NumericUpDownPage/></TabItem>
+	<TabItem Header="NumericUpDown"><pages:NumericUpDownPage/></TabItem>
     <TabItem Header="ProgressBar"><pages:ProgressBarPage/></TabItem>
     <TabItem Header="RadioButton"><pages:RadioButtonPage/></TabItem>
     <TabItem Header="Slider"><pages:SliderPage/></TabItem>

samples/ControlCatalog/Pages/CanvasPage.xaml

@@ -11,7 +11,8 @@
               <GradientStop Offset="1" Color="Transparent"/>
             </LinearGradientBrush.GradientStops>
           </LinearGradientBrush>
-        </Rectangle.OpacityMask>      </Rectangle>
+        </Rectangle.OpacityMask>     
+      </Rectangle>
       <Ellipse Fill="Green" Width="58" Height="58" Canvas.Left="88" Canvas.Top="100"/>
       <Path Fill="Orange" Data="M 0,0 c 0,0 50,0 50,-50 c 0,0 50,0 50,50 h -50 v 50 l -50,-50 Z" Canvas.Left="30" Canvas.Top="250"/>
       <Path Fill="OrangeRed" Canvas.Left="180" Canvas.Top="250">

samples/ControlCatalog/Pages/ListBoxPage.xaml

@@ -0,0 +1,13 @@
+<UserControl xmlns="https://github.com/avaloniaui">
+  <StackPanel Orientation="Vertical" Spacing="4">
+    <TextBlock Classes="h1">ListBox</TextBlock>
+    <TextBlock Classes="h2">Hosts a collection of ListBoxItem.</TextBlock>
+
+    <StackPanel Orientation="Horizontal"
+              Margin="0,16,0,0"
+              HorizontalAlignment="Center"
+              Spacing="16">
+      <ListBox Items="{Binding}" Width="250" Height="350"></ListBox>
+    </StackPanel>
+  </StackPanel>
+</UserControl>

samples/ControlCatalog/Pages/ListBoxPage.xaml.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+
+namespace ControlCatalog.Pages
+{
+    public class ListBoxPage : UserControl
+    {
+        public ListBoxPage()
+        {
+            this.InitializeComponent();
+            DataContext = Enumerable.Range(1, 10).Select(i => $"Item {i}" )
+                .ToArray();
+        }
+
+        private void InitializeComponent()
+        {
+            AvaloniaXamlLoader.Load(this);
+        }
+
+    }
+}

samples/ControlCatalog/Pages/MenuPage.xaml

@@ -7,29 +7,44 @@
               Margin="0,16,0,0"
               HorizontalAlignment="Center"
               Spacing="16">
-            <Menu>
+            <StackPanel>
-                <MenuItem Header="_First">
+                <TextBlock Classes="h3" Margin="4 8">Defined in XAML</TextBlock>
-                    <MenuItem Header="Standard _Menu Item"/>
+                <Menu>
-                    <Separator/>
+                    <MenuItem Header="_First">
-                    <MenuItem Header="Menu with _Submenu">
+                        <MenuItem Header="Standard _Menu Item"/>
-                        <MenuItem Header="Submenu _1"/>
+                        <Separator/>
-                        <MenuItem Header="Submenu _2"/>
+                        <MenuItem Header="Menu with _Submenu">
+                            <MenuItem Header="Submenu _1"/>
+                            <MenuItem Header="Submenu _2"/>
+                        </MenuItem>
+                        <MenuItem Header="Menu Item with _Icon">
+                            <MenuItem.Icon>
+                                <Image Source="resm:ControlCatalog.Assets.github_icon.png"/>
+                            </MenuItem.Icon>
+                        </MenuItem>
+                        <MenuItem Header="Menu Item with _Checkbox">
+                            <MenuItem.Icon>
+                                <CheckBox BorderThickness="0" IsHitTestVisible="False" IsChecked="True"/>
+                            </MenuItem.Icon>
+                        </MenuItem>
                     </MenuItem>
-                    <MenuItem Header="Menu Item with _Icon">
+                    <MenuItem Header="_Second">
-                        <MenuItem.Icon>
+                        <MenuItem Header="Second _Menu Item"/>
-                            <Image Source="resm:ControlCatalog.Assets.github_icon.png"/>
-                        </MenuItem.Icon>
                     </MenuItem>
-                    <MenuItem Header="Menu Item with _Checkbox">
+                </Menu>
-                        <MenuItem.Icon>
+            </StackPanel>
-                            <CheckBox BorderThickness="0" IsHitTestVisible="False" IsChecked="True"/>
+
-                        </MenuItem.Icon>
+            <StackPanel>
-                    </MenuItem>
+                <TextBlock Classes="h3" Margin="4 8">Dyanamically generated</TextBlock>
-                </MenuItem>
+                <Menu Items="{Binding}">
-                <MenuItem Header="_Second">
+                    <Menu.Styles>
-                    <MenuItem Header="Second _Menu Item"/>
+                        <Style Selector="MenuItem">
-                </MenuItem>
+                            <Setter Property="Header" Value="{Binding Header}"/>
-            </Menu>
+                            <Setter Property="Items" Value="{Binding Items}"/>
+                        </Style>
+                    </Menu.Styles>
+                </Menu>
+            </StackPanel>
         </StackPanel>
     </StackPanel>
-</UserControl>
+</UserControl>

samples/ControlCatalog/Pages/MenuPage.xaml.cs

@@ -1,3 +1,4 @@
+using System.Collections.Generic;
 using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
 
@@ -8,6 +9,37 @@ namespace ControlCatalog.Pages
         public MenuPage()
         {
             this.InitializeComponent();
+            DataContext = new[]
+            {
+                new MenuItemViewModel
+                {
+                    Header = "_File",
+                    Items = new[]
+                    {
+                        new MenuItemViewModel { Header = "_Open..." },
+                        new MenuItemViewModel { Header = "Save" },
+                        new MenuItemViewModel { Header = "-" },
+                        new MenuItemViewModel
+                        {
+                            Header = "Recent",
+                            Items = new[]
+                            {
+                                new MenuItemViewModel { Header = "File1.txt" },
+                                new MenuItemViewModel { Header = "File2.txt" },
+                            }
+                        },
+                    }
+                },
+                new MenuItemViewModel
+                {
+                    Header = "_Edit",
+                    Items = new[]
+                    {
+                        new MenuItemViewModel { Header = "_Copy" },
+                        new MenuItemViewModel { Header = "_Paste" },
+                    }
+                }
+            };
         }
 
         private void InitializeComponent()
@@ -15,4 +47,10 @@ namespace ControlCatalog.Pages
             AvaloniaXamlLoader.Load(this);
         }
     }
+
+    public class MenuItemViewModel
+    {
+        public string Header { get; set; }
+        public IList<MenuItemViewModel> Items { get; set; }
+    }
 }

samples/ControlCatalog/Pages/NumericUpDownPage.xaml

@@ -14,7 +14,7 @@
         <CheckBox Grid.Row="1" Grid.Column="1" IsChecked="{Binding #upDown.IsReadOnly}" VerticalAlignment="Center" Margin="2"/>
 
         <TextBlock Grid.Row="2" Grid.Column="0" VerticalAlignment="Center" Margin="2">AllowSpin:</TextBlock>
-        <CheckBox Grid.Row="2" Grid.Column="1" IsChecked="{Binding #upDown.AllowSpin}" IsEnabled="{Binding #upDown.!IsReadOnly}" VerticalAlignment="Center" Margin="2"/>
+        <CheckBox Grid.Row="2" Grid.Column="1" IsChecked="{Binding #upDown.AllowSpin}" VerticalAlignment="Center" Margin="2"/>
 
         <TextBlock Grid.Row="3" Grid.Column="0" VerticalAlignment="Center" Margin="2">ClipValueToMinMax:</TextBlock>
         <CheckBox Grid.Row="3" Grid.Column="1" IsChecked="{Binding #upDown.ClipValueToMinMax}" VerticalAlignment="Center" Margin="2"/>
@@ -77,4 +77,4 @@
     </StackPanel>
 
   </StackPanel>
-</UserControl>
+</UserControl>

samples/ControlCatalog/Pages/ScreenPage.cs

@@ -42,7 +42,11 @@ namespace ControlCatalog.Pages
                     context.DrawRectangle(p, boundsRect);
                     context.DrawRectangle(p, workingAreaRect);
                     
-                    FormattedText text = new FormattedText();
+                    FormattedText text = new FormattedText()
+                    {
+                        Typeface = Typeface.Default
+                    };
+
                     text.Text = $"Bounds: {screen.Bounds.Width}:{screen.Bounds.Height}";
                     context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height), text);
                     
@@ -59,4 +63,4 @@ namespace ControlCatalog.Pages
             context.DrawRectangle(p, new Rect(w.Position.X / 10f + Math.Abs(_leftMost), w.Position.Y / 10, w.Bounds.Width / 10, w.Bounds.Height / 10));
         }
     }
-}
+}

samples/ControlCatalog/SideBar.xaml

@@ -36,7 +36,7 @@
     <Setter Property="Opacity" Value="0.5"/>
     <Setter Property="Transitions">
       <Transitions>
-        <DoubleTransition Property="Opacity" Duration="0:0:0.5"/>
+        <DoubleTransition Property="Opacity" Duration="0:0:0.2"/>
       </Transitions>
     </Setter>
   </Style>

samples/RenderDemo/SideBar.xaml

@@ -37,7 +37,7 @@
     <Setter Property="Opacity" Value="0.5"/>
     <Setter Property="Transitions">
       <Transitions>
-        <DoubleTransition Property="Opacity" Duration="0:0:0.5"/>
+        <DoubleTransition Property="Opacity" Duration="0:0:0.2"/>
       </Transitions>
     </Setter>
   </Style>

samples/RenderDemo/ViewModels/AnimationsPageViewModel.cs

@@ -10,21 +10,21 @@ namespace RenderDemo.ViewModels
 
         public AnimationsPageViewModel()
         {
-            ToggleGlobalPlayState = ReactiveCommand.Create(()=>TogglePlayState());
+            ToggleGlobalPlayState = ReactiveCommand.Create(() => TogglePlayState());
         }
 
         void TogglePlayState()
         {
-            switch (Timing.GetGlobalPlayState())
+            switch (Animation.GlobalPlayState)
             {
                 case PlayState.Run:
                     PlayStateText = "Resume all animations";
-                    Timing.SetGlobalPlayState(PlayState.Pause);
+                    Animation.GlobalPlayState = PlayState.Pause;
                     break;
 
                 case PlayState.Pause:
                     PlayStateText = "Pause all animations";
-                    Timing.SetGlobalPlayState(PlayState.Run);
+                    Animation.GlobalPlayState = PlayState.Run;
                     break;
             }
         }
@@ -36,5 +36,5 @@ namespace RenderDemo.ViewModels
         }
 
         public ReactiveCommand ToggleGlobalPlayState { get; }
-     }
+    }
 }

samples/interop/Direct3DInteropSample/MainWindow.cs

@@ -1,81 +1,83 @@
-using System;
+// Copyright (c) The Avalonia Project. All rights reserved.
-using System.Collections.Generic;
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
-using System.Linq;
+
-using System.Text;
+using System;
-using System.Threading.Tasks;
+
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Direct2D1;
 using Avalonia.Direct2D1.Media;
 using Avalonia.Markup.Xaml;
 using Avalonia.Platform;
 using Avalonia.Rendering;
+
 using SharpDX;
 using SharpDX.D3DCompiler;
 using SharpDX.Direct2D1;
 using SharpDX.Direct3D;
 using SharpDX.Direct3D11;
 using SharpDX.DXGI;
-using SharpDX.WIC;
+
-using SharpDX.Mathematics;
 using AlphaMode = SharpDX.Direct2D1.AlphaMode;
 using Buffer = SharpDX.Direct3D11.Buffer;
-using DeviceContext = SharpDX.Direct3D11.DeviceContext;
+using DeviceContext = SharpDX.Direct2D1.DeviceContext;
-using Factory1 = SharpDX.DXGI.Factory1;
+using Factory2 = SharpDX.DXGI.Factory2;
 using InputElement = SharpDX.Direct3D11.InputElement;
 using Matrix = SharpDX.Matrix;
 using PixelFormat = SharpDX.Direct2D1.PixelFormat;
+using Resource = SharpDX.Direct3D11.Resource;
 
 namespace Direct3DInteropSample
 {
-    class MainWindow : Window
+    public class MainWindow : Window
     {
-        private SharpDX.Direct3D11.Device _d3dDevice;
+        Texture2D _backBuffer;
-        private SharpDX.DXGI.Device _dxgiDevice;
+        RenderTargetView _renderView;
-        Texture2D backBuffer = null;
+        Texture2D _depthBuffer;
-        RenderTargetView renderView = null;
+        DepthStencilView _depthView;
-        Texture2D depthBuffer = null;
-        DepthStencilView depthView = null;
         private readonly SwapChain _swapChain;
-        private SwapChainDescription _desc;
+        private SwapChainDescription1 _desc;
         private Matrix _proj = Matrix.Identity;
-        private Matrix _view;
+        private readonly Matrix _view;
         private Buffer _contantBuffer;
-        private SharpDX.Direct2D1.Device _d2dDevice;
+        private DeviceContext _deviceContext;
-        private SharpDX.Direct2D1.DeviceContext _d2dContext;
+        private readonly MainWindowViewModel _model;
-        private RenderTarget _d2dRenderTarget;
-        private MainWindowViewModel _model;
 
         public MainWindow()
         {
-            _dxgiDevice = AvaloniaLocator.Current.GetService<SharpDX.DXGI.Device>();
-            _d3dDevice = _dxgiDevice.QueryInterface<SharpDX.Direct3D11.Device>();
-            _d2dDevice = AvaloniaLocator.Current.GetService<SharpDX.Direct2D1.Device>();
             DataContext = _model = new MainWindowViewModel();
-            _desc = new SwapChainDescription()
+
+            _desc = new SwapChainDescription1()
             {
                 BufferCount = 1,
-                ModeDescription =
+                Width = (int)ClientSize.Width,
-                   new ModeDescription((int)ClientSize.Width, (int)ClientSize.Height,
+                Height = (int)ClientSize.Height,
-                            new Rational(60, 1), Format.R8G8B8A8_UNorm),
+                Format = Format.R8G8B8A8_UNorm,                
-                IsWindowed = true,
-                OutputHandle = PlatformImpl?.Handle.Handle ?? IntPtr.Zero,
                 SampleDescription = new SampleDescription(1, 0),
                 SwapEffect = SwapEffect.Discard,
                 Usage = Usage.RenderTargetOutput
             };
 
-            _swapChain = new SwapChain(new Factory1(), _d3dDevice, _desc);
+            using (var factory = Direct2D1Platform.DxgiDevice.Adapter.GetParent<Factory2>())
+            {
+                _swapChain = new SwapChain1(factory, Direct2D1Platform.DxgiDevice, PlatformImpl?.Handle.Handle ?? IntPtr.Zero, ref _desc);
+            }              
 
-            _d2dContext = new SharpDX.Direct2D1.DeviceContext(_d2dDevice, DeviceContextOptions.None)
+            _deviceContext = new DeviceContext(Direct2D1Platform.Direct2D1Device, DeviceContextOptions.None)
             {
                 DotsPerInch = new Size2F(96, 96)
             };
 
             CreateMesh();
+
             _view = Matrix.LookAtLH(new Vector3(0, 0, -5), new Vector3(0, 0, 0), Vector3.UnitY);
+
             this.GetObservable(ClientSizeProperty).Subscribe(Resize);
+
             Resize(ClientSize);
+
             AvaloniaXamlLoader.Load(this);
+
             Background = Avalonia.Media.Brushes.Transparent;
         }
 
@@ -83,29 +85,32 @@ namespace Direct3DInteropSample
         protected override void HandlePaint(Rect rect)
         {
             var viewProj = Matrix.Multiply(_view, _proj);
-            var context = _d3dDevice.ImmediateContext;
+            var context = Direct2D1Platform.Direct3D11Device.ImmediateContext;
+
             // Clear views
-            context.ClearDepthStencilView(depthView, DepthStencilClearFlags.Depth, 1.0f, 0);
+            context.ClearDepthStencilView(_depthView, DepthStencilClearFlags.Depth, 1.0f, 0);
-            context.ClearRenderTargetView(renderView, Color.White);
+            context.ClearRenderTargetView(_renderView, Color.White);
 
             // Update WorldViewProj Matrix
-            var worldViewProj = Matrix.RotationX((float) _model.RotationX) * Matrix.RotationY((float) _model.RotationY) *
+            var worldViewProj = Matrix.RotationX((float)_model.RotationX) * Matrix.RotationY((float)_model.RotationY)
-                                Matrix.RotationZ((float) _model.RotationZ)
+                                                                          * Matrix.RotationZ((float)_model.RotationZ)
-                                * Matrix.Scaling((float) _model.Zoom) * viewProj;
+                                                                          * Matrix.Scaling((float)_model.Zoom)
+                                                                          * viewProj;
             worldViewProj.Transpose();
             context.UpdateSubresource(ref worldViewProj, _contantBuffer);
 
             // Draw the cube
             context.Draw(36, 0);
             base.HandlePaint(rect);
+
             // Present!
             _swapChain.Present(0, PresentFlags.None);
         }
 
-        
+        private void CreateMesh()
-        void CreateMesh()
         {
-            var device = _d3dDevice;
+            var device = Direct2D1Platform.Direct3D11Device;
+
             // Compile Vertex and Pixel shaders
             var vertexShaderByteCode = ShaderBytecode.CompileFromFile("MiniCube.fx", "VS", "vs_4_0");
             var vertexShader = new VertexShader(device, vertexShaderByteCode);
@@ -114,63 +119,72 @@ namespace Direct3DInteropSample
             var pixelShader = new PixelShader(device, pixelShaderByteCode);
 
             var signature = ShaderSignature.GetInputSignature(vertexShaderByteCode);
+
+            var inputElements = new[]
+                                {
+                                    new InputElement("POSITION", 0, Format.R32G32B32A32_Float, 0, 0),
+                                    new InputElement("COLOR", 0, Format.R32G32B32A32_Float, 16, 0)
+                                };
+
             // Layout from VertexShader input signature
-            var layout = new InputLayout(device, signature, new[]
+            var layout = new InputLayout(
-                    {
+                device,
-                        new InputElement("POSITION", 0, Format.R32G32B32A32_Float, 0, 0),
+                signature,
-                        new InputElement("COLOR", 0, Format.R32G32B32A32_Float, 16, 0)
+                inputElements);
-                    });
+
-            
+            // Instantiate Vertex buffer from vertex data
-            // Instantiate Vertex buiffer from vertex data
+            var vertices = Buffer.Create(
-            var vertices = Buffer.Create(device, BindFlags.VertexBuffer, new[]
+                device,
-                                  {
+                BindFlags.VertexBuffer,
-                                      new Vector4(-1.0f, -1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f), // Front
+                new[]
-                                      new Vector4(-1.0f,  1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f),
+                {
-                                      new Vector4( 1.0f,  1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f),
+                    new Vector4(-1.0f, -1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f), // Front
-                                      new Vector4(-1.0f, -1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f),
+                    new Vector4(-1.0f,  1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f),
-                                      new Vector4( 1.0f,  1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f),
+                    new Vector4( 1.0f,  1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f),
-                                      new Vector4( 1.0f, -1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f),
+                    new Vector4(-1.0f, -1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f),
-
+                    new Vector4( 1.0f,  1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f),
-                                      new Vector4(-1.0f, -1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f), // BACK
+                    new Vector4( 1.0f, -1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 0.0f, 1.0f),
-                                      new Vector4( 1.0f,  1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f),
+
-                                      new Vector4(-1.0f,  1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f),
+                    new Vector4(-1.0f, -1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f), // BACK
-                                      new Vector4(-1.0f, -1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f),
+                    new Vector4( 1.0f,  1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f),
-                                      new Vector4( 1.0f, -1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f),
+                    new Vector4(-1.0f,  1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f),
-                                      new Vector4( 1.0f,  1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f),
+                    new Vector4(-1.0f, -1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f),
-
+                    new Vector4( 1.0f, -1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f),
-                                      new Vector4(-1.0f, 1.0f, -1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f), // Top
+                    new Vector4( 1.0f,  1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 0.0f, 1.0f),
-                                      new Vector4(-1.0f, 1.0f,  1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f),
+
-                                      new Vector4( 1.0f, 1.0f,  1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f),
+                    new Vector4(-1.0f, 1.0f, -1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f), // Top
-                                      new Vector4(-1.0f, 1.0f, -1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f),
+                    new Vector4(-1.0f, 1.0f,  1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f),
-                                      new Vector4( 1.0f, 1.0f,  1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f),
+                    new Vector4( 1.0f, 1.0f,  1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f),
-                                      new Vector4( 1.0f, 1.0f, -1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f),
+                    new Vector4(-1.0f, 1.0f, -1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f),
-
+                    new Vector4( 1.0f, 1.0f,  1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f),
-                                      new Vector4(-1.0f,-1.0f, -1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f), // Bottom
+                    new Vector4( 1.0f, 1.0f, -1.0f,  1.0f), new Vector4(0.0f, 0.0f, 1.0f, 1.0f),
-                                      new Vector4( 1.0f,-1.0f,  1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f),
+
-                                      new Vector4(-1.0f,-1.0f,  1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f),
+                    new Vector4(-1.0f, -1.0f, -1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f), // Bottom
-                                      new Vector4(-1.0f,-1.0f, -1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f),
+                    new Vector4( 1.0f, -1.0f,  1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f),
-                                      new Vector4( 1.0f,-1.0f, -1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f),
+                    new Vector4(-1.0f, -1.0f,  1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f),
-                                      new Vector4( 1.0f,-1.0f,  1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f),
+                    new Vector4(-1.0f, -1.0f, -1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f),
-
+                    new Vector4( 1.0f, -1.0f, -1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f),
-                                      new Vector4(-1.0f, -1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f), // Left
+                    new Vector4( 1.0f, -1.0f,  1.0f,  1.0f), new Vector4(1.0f, 1.0f, 0.0f, 1.0f),
-                                      new Vector4(-1.0f, -1.0f,  1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f),
+
-                                      new Vector4(-1.0f,  1.0f,  1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f),
+                    new Vector4(-1.0f, -1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f), // Left
-                                      new Vector4(-1.0f, -1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f),
+                    new Vector4(-1.0f, -1.0f,  1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f),
-                                      new Vector4(-1.0f,  1.0f,  1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f),
+                    new Vector4(-1.0f,  1.0f,  1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f),
-                                      new Vector4(-1.0f,  1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f),
+                    new Vector4(-1.0f, -1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f),
-
+                    new Vector4(-1.0f,  1.0f,  1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f),
-                                      new Vector4( 1.0f, -1.0f, -1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f), // Right
+                    new Vector4(-1.0f,  1.0f, -1.0f, 1.0f), new Vector4(1.0f, 0.0f, 1.0f, 1.0f),
-                                      new Vector4( 1.0f,  1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f),
+
-                                      new Vector4( 1.0f, -1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f),
+                    new Vector4( 1.0f, -1.0f, -1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f), // Right
-                                      new Vector4( 1.0f, -1.0f, -1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f),
+                    new Vector4( 1.0f,  1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f),
-                                      new Vector4( 1.0f,  1.0f, -1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f),
+                    new Vector4( 1.0f, -1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f),
-                                      new Vector4( 1.0f,  1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f),
+                    new Vector4( 1.0f, -1.0f, -1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f),
-                            });
+                    new Vector4( 1.0f,  1.0f, -1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f),
+                    new Vector4( 1.0f,  1.0f,  1.0f, 1.0f), new Vector4(0.0f, 1.0f, 1.0f, 1.0f),
+                });
 
             // Create Constant Buffer
             _contantBuffer = new Buffer(device, Utilities.SizeOf<Matrix>(), ResourceUsage.Default, BindFlags.ConstantBuffer, CpuAccessFlags.None, ResourceOptionFlags.None, 0);
 
-            var context = _d3dDevice.ImmediateContext;
+            var context = Direct2D1Platform.Direct3D11Device.ImmediateContext;
 
             // Prepare All the stages
             context.InputAssembler.InputLayout = layout;
@@ -181,63 +195,73 @@ namespace Direct3DInteropSample
             context.PixelShader.Set(pixelShader);
         }
 
-        void Resize(Size size)
+        private void Resize(Size size)
         {
-            Utilities.Dispose(ref _d2dRenderTarget);
+            Utilities.Dispose(ref _deviceContext);
-            Utilities.Dispose(ref backBuffer);
+            Utilities.Dispose(ref _backBuffer);
-            Utilities.Dispose(ref renderView);
+            Utilities.Dispose(ref _renderView);
-            Utilities.Dispose(ref depthBuffer);
+            Utilities.Dispose(ref _depthBuffer);
-            Utilities.Dispose(ref depthView);
+            Utilities.Dispose(ref _depthView);
-            var context = _d3dDevice.ImmediateContext;
+            var context = Direct2D1Platform.Direct3D11Device.ImmediateContext;
+
             // Resize the backbuffer
-            _swapChain.ResizeBuffers(_desc.BufferCount, (int)size.Width, (int)size.Height, Format.Unknown, SwapChainFlags.None);
+            _swapChain.ResizeBuffers(0, 0, 0, Format.Unknown, SwapChainFlags.None);
 
             // Get the backbuffer from the swapchain
-            backBuffer = Texture2D.FromSwapChain<Texture2D>(_swapChain, 0);
+            _backBuffer = Resource.FromSwapChain<Texture2D>(_swapChain, 0);
 
             // Renderview on the backbuffer
-            renderView = new RenderTargetView(_d3dDevice, backBuffer);
+            _renderView = new RenderTargetView(Direct2D1Platform.Direct3D11Device, _backBuffer);
 
             // Create the depth buffer
-            depthBuffer = new Texture2D(_d3dDevice, new Texture2DDescription()
+            _depthBuffer = new Texture2D(
-            {
+                Direct2D1Platform.Direct3D11Device,
-                Format = Format.D32_Float_S8X24_UInt,
+                new Texture2DDescription()
-                ArraySize = 1,
+                {
-                MipLevels = 1,
+                    Format = Format.D32_Float_S8X24_UInt,
-                Width = (int)size.Width,
+                    ArraySize = 1,
-                Height = (int)size.Height,
+                    MipLevels = 1,
-                SampleDescription = new SampleDescription(1, 0),
+                    Width = (int)size.Width,
-                Usage = ResourceUsage.Default,
+                    Height = (int)size.Height,
-                BindFlags = BindFlags.DepthStencil,
+                    SampleDescription = new SampleDescription(1, 0),
-                CpuAccessFlags = CpuAccessFlags.None,
+                    Usage = ResourceUsage.Default,
-                OptionFlags = ResourceOptionFlags.None
+                    BindFlags = BindFlags.DepthStencil,
-            });
+                    CpuAccessFlags = CpuAccessFlags.None,
+                    OptionFlags = ResourceOptionFlags.None
+                });
 
             // Create the depth buffer view
-            depthView = new DepthStencilView(_d3dDevice, depthBuffer);
+            _depthView = new DepthStencilView(Direct2D1Platform.Direct3D11Device, _depthBuffer);
 
             // Setup targets and viewport for rendering
             context.Rasterizer.SetViewport(new Viewport(0, 0, (int)size.Width, (int)size.Height, 0.0f, 1.0f));
-            context.OutputMerger.SetTargets(depthView, renderView);
+            context.OutputMerger.SetTargets(_depthView, _renderView);
 
             // Setup new projection matrix with correct aspect ratio
             _proj = Matrix.PerspectiveFovLH((float)Math.PI / 4.0f, (float)(size.Width / size.Height), 0.1f, 100.0f);
 
             using (var dxgiBackBuffer = _swapChain.GetBackBuffer<Surface>(0))
             {
-                _d2dRenderTarget = new RenderTarget(AvaloniaLocator.Current.GetService<SharpDX.Direct2D1.Factory>()
+                var renderTarget = new SharpDX.Direct2D1.RenderTarget(
-                    , dxgiBackBuffer, new RenderTargetProperties
+                    Direct2D1Platform.Direct2D1Factory,
+                    dxgiBackBuffer,
+                    new RenderTargetProperties
                     {
                         DpiX = 96,
                         DpiY = 96,
                         Type = RenderTargetType.Default,
-                        PixelFormat = new PixelFormat(Format.Unknown, AlphaMode.Premultiplied)
+                        PixelFormat = new PixelFormat(
+                            Format.Unknown,
+                            AlphaMode.Premultiplied)
                     });
-            }
 
+                _deviceContext = renderTarget.QueryInterface<DeviceContext>();
+
+                renderTarget.Dispose();
+            }
         }
 
-        class D3DRenderTarget: IRenderTarget
+        private class D3DRenderTarget : IRenderTarget
         {
             private readonly MainWindow _window;
 
@@ -245,16 +269,14 @@ namespace Direct3DInteropSample
             {
                 _window = window;
             }
+
             public void Dispose()
             {
-                
             }
 
             public IDrawingContextImpl CreateDrawingContext(IVisualBrushRenderer visualBrushRenderer)
             {
-                return new DrawingContextImpl(visualBrushRenderer, null, _window._d2dRenderTarget,
+                return new DrawingContextImpl(visualBrushRenderer, null, _window._deviceContext);
-                    AvaloniaLocator.Current.GetService<SharpDX.DirectWrite.Factory>(),
-                    AvaloniaLocator.Current.GetService<ImagingFactory>());
             }
         }
 

src/Android/Avalonia.Android/AndroidPlatform.cs

@@ -1,8 +1,4 @@
 using System;
-using System.IO;
-using System.Linq;
-using Android.Content;
-using Android.Views;
 using Avalonia.Android.Platform;
 using Avalonia.Android.Platform.Input;
 using Avalonia.Android.Platform.SkiaPlatform;
@@ -79,4 +75,4 @@ namespace Avalonia.Android
             return new PopupImpl();
         }
     }
-}
+}

src/Android/Avalonia.Android/AndroidThreadingInterface.cs

@@ -1,16 +1,7 @@
 using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.Linq;
 using System.Reactive.Disposables;
-using System.Text;
 using System.Threading;
-using Android.App;
-using Android.Content;
 using Android.OS;
-using Android.Runtime;
-using Android.Views;
-using Android.Widget;
 using Avalonia.Platform;
 using Avalonia.Threading;
 
@@ -88,4 +79,3 @@ namespace Avalonia.Android
         public event Action<DispatcherPriority?> Signaled;
     }
 }
- 

src/Android/Avalonia.Android/AppBuilder.cs

@@ -1,16 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-using Android.App;
-using Android.Content;
-using Android.OS;
-using Android.Runtime;
-using Android.Views;
-using Android.Widget;
 using Avalonia.Controls;
-using Avalonia.Platform;
 using Avalonia.Shared.PlatformSupport;
 
 namespace Avalonia
@@ -23,4 +11,4 @@ namespace Avalonia
 
         }
     }
-}
+}

src/Android/Avalonia.Android/AvaloniaActivity.cs

@@ -1,14 +1,7 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
 
 using Android.App;
-using Android.Content;
 using Android.OS;
-using Android.Runtime;
 using Android.Views;
-using Android.Widget;
 
 namespace Avalonia.Android
 {
@@ -48,4 +41,4 @@ namespace Avalonia.Android
             return View.DispatchKeyEvent(e);
         }
     }
-}
+}

src/Android/Avalonia.Android/AvaloniaView.cs

@@ -1,12 +1,5 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-using Android.App;
 using Android.Content;
-using Android.OS;
-using Android.Runtime;
 using Android.Views;
 using Android.Widget;
 using Avalonia.Android.Platform.SkiaPlatform;
@@ -66,4 +59,4 @@ namespace Avalonia.Android
             public IDisposable ShowDialog() => null;
         }
     }
-}
+}

src/Android/Avalonia.Android/CursorFactory.cs

@@ -9,4 +9,4 @@ namespace Avalonia.Android
         public IPlatformHandle GetCursor(StandardCursorType cursorType)
             => new PlatformHandle(IntPtr.Zero, "ZeroCursor");
     }
-}
+}

src/Android/Avalonia.Android/Platform/ClipboardImpl.cs

@@ -1,9 +1,9 @@
+using System.Threading.Tasks;
 using Android.Content;
 using Android.Runtime;
 using Android.Views;
 using Avalonia.Input.Platform;
 using Avalonia.Platform;
-using System.Threading.Tasks;
 
 namespace Avalonia.Android.Platform
 {
@@ -44,4 +44,4 @@ namespace Avalonia.Android.Platform
             return Task.FromResult<object>(null);
         }
     }
-}
+}

src/Android/Avalonia.Android/Platform/Input/AndroidKeyboardDevice.cs

@@ -1,12 +1,11 @@
-using System;
-using Avalonia.Input;
 //using Android.InputMethodServices;
 using System.Collections.Generic;
 using Android.Views;
+using Avalonia.Input;
 
 namespace Avalonia.Android.Platform.Input
 {
-  public class AndroidKeyboardDevice : KeyboardDevice, IKeyboardDevice {
+    public class AndroidKeyboardDevice : KeyboardDevice, IKeyboardDevice {
     private static readonly Dictionary<Keycode, Key> KeyDic = new Dictionary<Keycode, Key>
      {
          //   { Keycode.Cancel?, Key.Cancel },

src/Android/Avalonia.Android/Platform/SkiaPlatform/AndroidFramebuffer.cs

@@ -102,4 +102,4 @@ namespace Avalonia.Android.Platform.SkiaPlatform
             uint reserved6;
         }
     }
-}
+}

src/Android/Avalonia.Android/Platform/SkiaPlatform/InvalidationAwareSurfaceView.cs

@@ -1,17 +1,9 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-using Android.App;
 using Android.Content;
 using Android.Graphics;
 using Android.OS;
-using Android.Runtime;
 using Android.Util;
 using Android.Views;
-using Android.Widget;
-using Avalonia.Media;
 using Avalonia.Platform;
 
 namespace Avalonia.Android
@@ -90,4 +82,4 @@ namespace Avalonia.Android
         protected abstract void Draw();
         public string HandleDescriptor => "SurfaceView";
     }
-}
+}

src/Android/Avalonia.Android/Platform/SkiaPlatform/PopupImpl.cs

@@ -1,15 +1,8 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-using Android.App;
 using Android.Content;
 using Android.Graphics;
-using Android.OS;
 using Android.Runtime;
 using Android.Views;
-using Android.Widget;
 using Avalonia.Controls;
 using Avalonia.Platform;
 
@@ -116,4 +109,4 @@ namespace Avalonia.Android.Platform.SkiaPlatform
             //Not supported
         }
     }
-}
+}

src/Android/Avalonia.Android/Platform/SkiaPlatform/TopLevelImpl.cs

@@ -1,18 +1,15 @@
-using Android.App;
+using System;
+using System.Collections.Generic;
 using Android.Content;
 using Android.Graphics;
 using Android.Views;
+using Avalonia.Android.Platform.Input;
 using Avalonia.Android.Platform.Specific;
 using Avalonia.Android.Platform.Specific.Helpers;
+using Avalonia.Controls.Platform.Surfaces;
 using Avalonia.Input;
 using Avalonia.Input.Raw;
 using Avalonia.Platform;
-using System;
-using System.Collections.Generic;
-using System.Reactive.Disposables;
-using Avalonia.Android.Platform.Input;
-using Avalonia.Controls;
-using Avalonia.Controls.Platform.Surfaces;
 using Avalonia.Rendering;
 
 namespace Avalonia.Android.Platform.SkiaPlatform
@@ -196,4 +193,4 @@ namespace Avalonia.Android.Platform.SkiaPlatform
 
         ILockedFramebuffer IFramebufferPlatformSurface.Lock()=>new AndroidFramebuffer(_view.Holder.Surface);
     }
-}
+}

src/Android/Avalonia.Android/Platform/Specific/Helpers/AndroidKeyboardEventsHelper.cs

@@ -1,3 +1,5 @@
+using System;
+using System.ComponentModel;
 using Android.Content;
 using Android.Runtime;
 using Android.Views;
@@ -7,8 +9,6 @@ using Avalonia.Controls;
 using Avalonia.Input;
 using Avalonia.Input.Raw;
 using Avalonia.Platform;
-using System;
-using System.ComponentModel;
 
 namespace Avalonia.Android.Platform.Specific.Helpers
 {
@@ -120,7 +120,7 @@ namespace Avalonia.Android.Platform.Specific.Helpers
             _lastFocusedElement = element;
         }
 
-        public void ActivateAutoShowKeybord()
+        public void ActivateAutoShowKeyboard()
         {
             var kbDevice = (KeyboardDevice.Instance as INotifyPropertyChanged);
 
@@ -142,4 +142,4 @@ namespace Avalonia.Android.Platform.Specific.Helpers
             HandleEvents = false;
         }
     }
-}
+}

src/Android/Avalonia.Android/Platform/Specific/Helpers/AndroidTouchEventsHelper.cs

@@ -1,10 +1,8 @@
-using Android.Graphics;
+using System;
 using Android.Views;
 using Avalonia.Input;
 using Avalonia.Input.Raw;
-using Avalonia.Media;
 using Avalonia.Platform;
-using System;
 
 namespace Avalonia.Android.Platform.Specific.Helpers
 {
@@ -131,4 +129,4 @@ namespace Avalonia.Android.Platform.Specific.Helpers
             HandleEvents = false;
         }
     }
-}
+}

src/Android/Avalonia.Android/Platform/Specific/IAndroidView.cs

@@ -1,16 +1,9 @@
-using Android.Graphics;
 using Android.Views;
-using System;
-using System.Collections.Generic;
 
 namespace Avalonia.Android.Platform.Specific
 {
     public interface IAndroidView
     {
-
-
         View View { get; }
     }
-
+}
-
-}

src/Android/Avalonia.Android/PlatformIconLoader.cs

@@ -1,16 +1,5 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-using Android.App;
-using Android.Content;
-using Android.OS;
-using Android.Runtime;
-using Android.Views;
-using Android.Widget;
-using Avalonia.Platform;
 using System.IO;
+using Avalonia.Platform;
 
 namespace Avalonia.Android
 {
@@ -54,4 +43,4 @@ namespace Avalonia.Android
             stream.CopyTo(outputStream);
         }
     }
-}
+}

src/Android/Avalonia.Android/SystemDialogImpl.cs

@@ -18,4 +18,4 @@ namespace Avalonia.Android
             throw new NotImplementedException();
         }
     }
-}
+}

src/Avalonia.Animation/Animatable.cs

@@ -1,48 +1,20 @@
 // 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.Linq;
-using Avalonia.Data;
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using System.Reactive.Linq;
 using Avalonia.Collections;
-using Avalonia.Animation;
+using Avalonia.Data;
-using System.Collections.Generic;
-using System.Threading;
-using System.Collections.Concurrent;
 
 namespace Avalonia.Animation
 {
     /// <summary>
-    /// Base class for control which can have property transitions.
+    /// Base class for all animatable objects.
     /// </summary>
     public class Animatable : AvaloniaObject
-    {
+    { 
-        /// <summary>
-        /// Initializes this <see cref="Animatable"/> object.
-        /// </summary>
-        public Animatable()
-        {
-            Transitions = new Transitions();
-            AnimatableTimer = Timing.AnimationStateTimer
-                                .Select(p =>
-                                {
-                                    if (this._playState == PlayState.Pause)
-                                    {
-                                        return PlayState.Pause;
-                                    }
-                                    else return p;
-                                })
-                                .Publish()
-                                .RefCount();
-        }
-
-        /// <summary>
-        /// The specific animations timer for this control.
-        /// </summary>
-        /// <returns></returns>
-        public IObservable<PlayState> AnimatableTimer;
-
         /// <summary>
         /// Defines the <see cref="PlayState"/> property.
         /// </summary>
@@ -62,27 +34,25 @@ namespace Avalonia.Animation
         {
             get { return _playState; }
             set { SetAndRaise(PlayStateProperty, ref _playState, value); }
-
         }
 
-
         /// <summary>
         /// Defines the <see cref="Transitions"/> property.
         /// </summary>
-        public static readonly DirectProperty<Animatable, IEnumerable<ITransition>> TransitionsProperty =
+        public static readonly DirectProperty<Animatable, Transitions> TransitionsProperty =
-            AvaloniaProperty.RegisterDirect<Animatable, IEnumerable<ITransition>>(
+            AvaloniaProperty.RegisterDirect<Animatable, Transitions>(
                 nameof(Transitions),
                 o => o.Transitions,
                 (o, v) => o.Transitions = v);
 
-        private IEnumerable<ITransition> _transitions = new AvaloniaList<ITransition>();
+        private Transitions _transitions;
 
         /// <summary>
         /// Gets or sets the property transitions for the control.
         /// </summary>
-        public IEnumerable<ITransition> Transitions
+        public Transitions Transitions
         {
-            get { return _transitions; }
+            get { return _transitions ?? (_transitions = new Transitions()); }
             set { SetAndRaise(TransitionsProperty, ref _transitions, value); }
         }
 
@@ -103,6 +73,5 @@ namespace Avalonia.Animation
                 }
             }
         }
-
     }
-}
+}

src/Avalonia.Animation/Animation.cs

@@ -1,18 +1,14 @@
 // 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.Animation.Easings;
-using Avalonia.Animation;
-using Avalonia.Collections;
-using Avalonia.Metadata;
 using System;
 using System.Collections.Generic;
-using System.Collections.Specialized;
-using System.Reflection;
 using System.Linq;
-using System.Threading.Tasks;
-using System.Reactive.Linq;
 using System.Reactive.Disposables;
+using System.Reactive.Linq;
+using System.Threading.Tasks;
+using Avalonia.Animation.Easings;
+using Avalonia.Collections;
 
 namespace Avalonia.Animation
 {
@@ -21,6 +17,60 @@ namespace Avalonia.Animation
     /// </summary>
     public class Animation : AvaloniaList<KeyFrame>, IAnimation
     {
+        /// <summary>
+        /// Gets or sets the animation play state for all animations
+        /// </summary> 
+        public static PlayState GlobalPlayState { get; set; } = PlayState.Run;
+
+        /// <summary>
+        /// Gets or sets the active time of this animation.
+        /// </summary>
+        public TimeSpan Duration { get; set; }
+
+        /// <summary>
+        /// Gets or sets the repeat count for this animation.
+        /// </summary>
+        public RepeatCount RepeatCount { get; set; }
+
+        /// <summary>
+        /// Gets or sets the playback direction for this animation.
+        /// </summary>
+        public PlaybackDirection PlaybackDirection { get; set; }
+
+        /// <summary>
+        /// Gets or sets the value fill mode for this animation.
+        /// </summary>
+        public FillMode FillMode { get; set; }
+
+        /// <summary>
+        /// Gets or sets the easing function to be used for this animation.
+        /// </summary>
+        public Easing Easing { get; set; } = new LinearEasing();
+
+        /// <summary>
+        /// Gets or sets the speed multiple for this animation.
+        /// </summary>
+        public double SpeedRatio { get; set; } = 1d;
+
+        /// <summary> 
+        /// Gets or sets the delay time for this animation. 
+        /// </summary> 
+        /// <remarks>
+        /// Describes a delay to be added before the animation starts, and optionally between 
+        /// repeats of the animation if <see cref="DelayBetweenIterations"/> is set. 
+        /// </remarks> 
+        public TimeSpan Delay { get; set; }
+
+        /// <summary> 
+        /// Gets or sets a value indicating whether <see cref="Delay"/> will be applied between 
+        /// iterations of the animation.
+        /// </summary> 
+        /// <remarks>
+        /// If this property is not set, then <see cref="Delay"/> will only be applied to the first 
+        /// iteration of the animation. 
+        /// </remarks> 
+        public bool DelayBetweenIterations { get; set; }
+
         private readonly static List<(Func<AvaloniaProperty, bool> Condition, Type Animator)> Animators = new List<(Func<AvaloniaProperty, bool>, Type)>
         {
             ( prop => typeof(double).IsAssignableFrom(prop.PropertyType), typeof(DoubleAnimator) )
@@ -44,38 +94,6 @@ namespace Avalonia.Animation
             return null;
         }
 
-        public AvaloniaList<IAnimator> _animators { get; set; } = new AvaloniaList<IAnimator>();
-
-        /// <summary>
-        /// Run time of this animation.
-        /// </summary>
-        public TimeSpan Duration { get; set; }
-
-        /// <summary>
-        /// Delay time for this animation.
-        /// </summary>
-        public TimeSpan Delay { get; set; }
-
-        /// <summary>
-        /// The repeat count for this animation.
-        /// </summary>
-        public RepeatCount RepeatCount { get; set; }
-
-        /// <summary>
-        /// The playback direction for this animation.
-        /// </summary>
-        public PlaybackDirection PlaybackDirection { get; set; }
-
-        /// <summary>
-        /// The value fill mode for this animation.
-        /// </summary>
-        public FillMode FillMode { get; set; }
-
-        /// <summary>
-        /// Easing function to be used.
-        /// </summary>
-        public Easing Easing { get; set; } = new LinearEasing();
-
         private (IList<IAnimator> Animators, IList<IDisposable> subscriptions) InterpretKeyframes(Animatable control)
         {
             var handlerList = new List<(Type type, AvaloniaProperty property)>();

src/Avalonia.Animation/AnimationInstance`1.cs

@@ -0,0 +1,228 @@
+using System;
+using System.Linq;
+using System.Reactive.Linq;
+using Avalonia.Animation.Utils;
+using Avalonia.Data;
+using Avalonia.Reactive;
+
+namespace Avalonia.Animation
+{
+    /// <summary>
+    /// Handles interpolatoin and time-related functions 
+    /// for keyframe animations.
+    /// </summary>
+    internal class AnimationInstance<T> : SingleSubscriberObservableBase<T>
+    {
+        private T _lastInterpValue;
+        private T _firstKFValue;
+        private long _repeatCount;
+        private double _currentIteration;
+        private bool _isLooping;
+        private bool _gotFirstKFValue;
+        private bool _gotFirstFrameCount;
+        private bool _iterationDelay;
+        private FillMode _fillMode;
+        private PlaybackDirection _animationDirection;
+        private Animator<T> _parent;
+        private Animatable _targetControl;
+        private T _neutralValue;
+        private double _speedRatio;
+        private TimeSpan _delay;
+        private TimeSpan _duration;
+        private TimeSpan _firstFrameCount;
+        private TimeSpan _internalClock;
+        private TimeSpan? _previousClock;
+        private Easings.Easing _easeFunc;
+        private Action _onCompleteAction;
+        private Func<double, T, T> _interpolator;
+        private IDisposable _timerSubscription;
+
+        public AnimationInstance(Animation animation, Animatable control, Animator<T> animator, Action OnComplete, Func<double, T, T> Interpolator)
+        {
+            if (animation.SpeedRatio <= 0)
+                throw new InvalidOperationException("Speed ratio cannot be negative or zero.");
+
+            if (animation.Duration.TotalSeconds <= 0)
+                throw new InvalidOperationException("Duration cannot be negative or zero.");
+
+            _parent = animator;
+            _easeFunc = animation.Easing;
+            _targetControl = control;
+            _neutralValue = (T)_targetControl.GetValue(_parent.Property);
+
+            _speedRatio = animation.SpeedRatio;
+
+            _delay = animation.Delay;
+            _duration = animation.Duration;
+            _iterationDelay = animation.DelayBetweenIterations;
+
+            switch (animation.RepeatCount.RepeatType)
+            {
+                case RepeatType.None:
+                    _repeatCount = 1;
+                    break;
+                case RepeatType.Loop:
+                    _isLooping = true;
+                    break;
+                case RepeatType.Repeat:
+                    _repeatCount = (long)animation.RepeatCount.Value;
+                    break;
+            }
+
+            _animationDirection = animation.PlaybackDirection;
+            _fillMode = animation.FillMode;
+            _onCompleteAction = OnComplete;
+            _interpolator = Interpolator;
+        }
+
+        protected override void Unsubscribed()
+        {
+            _timerSubscription?.Dispose();
+        }
+
+        protected override void Subscribed()
+        {
+            _timerSubscription = Timing.AnimationsTimer
+                                       .Subscribe(p => this.Step(p));
+        }
+
+        public void Step(TimeSpan frameTick)
+        {
+            try
+            {
+                InternalStep(frameTick);
+            }
+            catch (Exception e)
+            {
+                PublishError(e);
+            }
+        }
+
+        private void DoComplete()
+        {
+            if (_fillMode == FillMode.Forward || _fillMode == FillMode.Both)
+                _targetControl.SetValue(_parent.Property, _lastInterpValue, BindingPriority.LocalValue);
+
+            _onCompleteAction?.Invoke();
+            PublishCompleted();
+        }
+
+        private void DoDelay()
+        {
+            if (_fillMode == FillMode.Backward || _fillMode == FillMode.Both)
+                if (_currentIteration == 0)
+                    PublishNext(_firstKFValue);
+                else
+                    PublishNext(_lastInterpValue);
+        }
+
+        private void DoPlayStatesAndTime(TimeSpan systemTime)
+        {
+            if (Animation.GlobalPlayState == PlayState.Stop || _targetControl.PlayState == PlayState.Stop)
+                DoComplete();
+
+            if (!_previousClock.HasValue)
+            {
+                _previousClock = systemTime;
+                _internalClock = TimeSpan.Zero;
+            }
+            else
+            {
+                if (Animation.GlobalPlayState == PlayState.Pause || _targetControl.PlayState == PlayState.Pause)
+                {
+                    _previousClock = systemTime;
+                    return;
+                }
+                var delta = systemTime - _previousClock;
+                _internalClock += delta.Value;
+                _previousClock = systemTime;
+            }
+
+            if (!_gotFirstKFValue)
+            {
+                _firstKFValue = (T)_parent.First().Value;
+                _gotFirstKFValue = true;
+            }
+
+            if (!_gotFirstFrameCount)
+            {
+                _firstFrameCount = _internalClock;
+                _gotFirstFrameCount = true;
+            }
+        }
+
+        private void InternalStep(TimeSpan systemTime)
+        {
+            DoPlayStatesAndTime(systemTime);
+ 
+            var time = _internalClock - _firstFrameCount;
+            var delayEndpoint = _delay;
+            var iterationEndpoint = delayEndpoint + _duration;
+
+            //determine if time is currently in the first iteration.
+            if (time >= TimeSpan.Zero & time <= iterationEndpoint)
+            {
+                _currentIteration = 1;
+            }
+            else if (time > iterationEndpoint)
+            {
+                //Subtract first iteration to properly get the subsequent iteration time
+                time -= iterationEndpoint;
+
+                if (!_iterationDelay & delayEndpoint > TimeSpan.Zero)
+                {
+                    delayEndpoint = TimeSpan.Zero;
+                    iterationEndpoint = _duration;
+                }
+
+                //Calculate the current iteration number
+                _currentIteration = (int)Math.Floor((double)time.Ticks / iterationEndpoint.Ticks) + 2;
+            }
+            else
+            {
+                _previousClock = systemTime;
+                return;
+            }
+
+            time = TimeSpan.FromTicks(time.Ticks % iterationEndpoint.Ticks);
+
+            if (!_isLooping)
+            {
+                if (_currentIteration > _repeatCount)
+                    DoComplete();
+
+                if (time > iterationEndpoint)
+                    DoComplete();
+            }
+
+            // Determine if the current iteration should have its normalized time inverted.
+            bool isCurIterReverse = _animationDirection == PlaybackDirection.Normal ? false :
+                                    _animationDirection == PlaybackDirection.Alternate ? (_currentIteration % 2 == 0) ? false : true :
+                                    _animationDirection == PlaybackDirection.AlternateReverse ? (_currentIteration % 2 == 0) ? true : false :
+                                    _animationDirection == PlaybackDirection.Reverse ? true : false;
+
+            if (delayEndpoint > TimeSpan.Zero & time < delayEndpoint)
+            {
+                DoDelay();
+            }
+            else
+            {
+                // Offset the delay time            
+                time -= delayEndpoint;
+                iterationEndpoint -= delayEndpoint;
+
+                // Normalize time
+                var interpVal = (double)time.Ticks / iterationEndpoint.Ticks;
+
+                if (isCurIterReverse)
+                    interpVal = 1 - interpVal;
+
+                // Ease and interpolate
+                var easedTime = _easeFunc.Ease(interpVal);
+                _lastInterpValue = _interpolator(easedTime, _neutralValue);
+
+                PublishNext(_lastInterpValue);
+            }
+        }
+    }
+}

src/Avalonia.Animation/AnimatorKeyFrame.cs

@@ -1,9 +1,5 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
 using System.ComponentModel;
-using Avalonia.Metadata;
-using Avalonia.Collections;
 using Avalonia.Data;
 using Avalonia.Reactive;
 
@@ -29,6 +25,7 @@ namespace Avalonia.Animation
             Cue = cue;
         }
 
+        internal bool isNeutral;
         public Type AnimatorType { get; }
         public Cue Cue { get; }
         public AvaloniaProperty Property { get; private set; }

src/Avalonia.Animation/AnimatorStateMachine`1.cs

@@ -1,273 +0,0 @@
-using System;
-using System.Linq;
-using Avalonia.Data;
-
-namespace Avalonia.Animation
-{
-    /// <summary>
-    /// Provides statefulness for an iteration of a keyframe animation.
-    /// </summary>
-    internal class AnimatorStateMachine<T> : IObservable<object>, IDisposable
-    {
-        object _lastInterpValue;
-        object _firstKFValue;
-
-        private ulong _delayTotalFrameCount;
-        private ulong _durationTotalFrameCount;
-        private ulong _delayFrameCount;
-        private ulong _durationFrameCount;
-        private ulong _repeatCount;
-        private ulong _currentIteration;
-
-        private bool _isLooping;
-        private bool _isRepeating;
-        private bool _isReversed;
-        private bool _checkLoopAndRepeat;
-        private bool _gotFirstKFValue;
-
-        private FillMode _fillMode;
-        private PlaybackDirection _animationDirection;
-        private KeyFramesStates _currentState;
-        private KeyFramesStates _savedState;
-        private Animator<T> _parent;
-        private Animation _targetAnimation;
-        private Animatable _targetControl;
-        private T _neutralValue;
-        internal bool _unsubscribe = false;
-        private IObserver<object> _targetObserver;
-        private readonly Action _onComplete;
-
-        [Flags]
-        private enum KeyFramesStates
-        {
-            Initialize,
-            DoDelay,
-            DoRun,
-            RunForwards,
-            RunBackwards,
-            RunApplyValue,
-            RunComplete,
-            Pause,
-            Stop,
-            Disposed
-        }
-
-        public AnimatorStateMachine(Animation animation, Animatable control, Animator<T> animator, Action onComplete)
-        {
-            _parent = animator;
-            _targetAnimation = animation;
-            _targetControl = control;
-            _neutralValue = (T)_targetControl.GetValue(_parent.Property);
-
-            _delayTotalFrameCount = (ulong)(animation.Delay.Ticks / Timing.FrameTick.Ticks);
-            _durationTotalFrameCount = (ulong)(animation.Duration.Ticks / Timing.FrameTick.Ticks);
-
-            switch (animation.RepeatCount.RepeatType)
-            {
-                case RepeatType.Loop:
-                    _isLooping = true;
-                    _checkLoopAndRepeat = true;
-                    break;
-                case RepeatType.Repeat:
-                    _isRepeating = true;
-                    _checkLoopAndRepeat = true;
-                    _repeatCount = animation.RepeatCount.Value;
-                    break;
-            }
-
-            _isReversed = (animation.PlaybackDirection & PlaybackDirection.Reverse) != 0;
-            _animationDirection = _targetAnimation.PlaybackDirection;
-            _fillMode = _targetAnimation.FillMode;
-
-            if (_durationTotalFrameCount > 0)
-                _currentState = KeyFramesStates.DoDelay;
-            else
-                _currentState = KeyFramesStates.DoRun;
-            _onComplete = onComplete;
-        }
-
-        public void Step(PlayState _playState, Func<double, T, T> Interpolator)
-        {
-            try
-            {
-                InternalStep(_playState, Interpolator);
-            }
-            catch (Exception e)
-            {
-                _targetObserver?.OnError(e);
-            }
-        }
-
-        private void InternalStep(PlayState _playState, Func<double, T, T> Interpolator)
-        {
-            if (!_gotFirstKFValue)
-            {
-                _firstKFValue = _parent.First().Value;
-                _gotFirstKFValue = true;
-            }
-
-            if (_currentState == KeyFramesStates.Disposed)
-                throw new InvalidProgramException("This KeyFrames Animation is already disposed.");
-
-            if (_playState == PlayState.Stop)
-                _currentState = KeyFramesStates.Stop;
-
-            // Save state and pause the machine
-            if (_playState == PlayState.Pause && _currentState != KeyFramesStates.Pause)
-            {
-                _savedState = _currentState;
-                _currentState = KeyFramesStates.Pause;
-            }
-
-            // Resume the previous state
-            if (_playState != PlayState.Pause && _currentState == KeyFramesStates.Pause)
-                _currentState = _savedState;
-
-            double _tempDuration = 0d, _easedTime;
-
-            bool handled = false;
-
-            while (!handled)
-            {
-                switch (_currentState)
-                {
-                    case KeyFramesStates.DoDelay:
-
-                        if (_fillMode == FillMode.Backward
-                         || _fillMode == FillMode.Both)
-                        {
-                            if (_currentIteration == 0)
-                            {
-                                _targetObserver.OnNext(_firstKFValue);
-                            }
-                            else
-                            {
-                                _targetObserver.OnNext(_lastInterpValue);
-                            }
-                        }
-
-                        if (_delayFrameCount > _delayTotalFrameCount)
-                        {
-                            _currentState = KeyFramesStates.DoRun;
-                        }
-                        else
-                        {
-                            handled = true;
-                            _delayFrameCount++;
-                        }
-                        break;
-
-                    case KeyFramesStates.DoRun:
-
-                        if (_isReversed)
-                            _currentState = KeyFramesStates.RunBackwards;
-                        else
-                            _currentState = KeyFramesStates.RunForwards;
-
-                        break;
-
-                    case KeyFramesStates.RunForwards:
-
-                        if (_durationFrameCount > _durationTotalFrameCount)
-                        {
-                            _currentState = KeyFramesStates.RunComplete;
-                        }
-                        else
-                        {
-                            _tempDuration = (double)_durationFrameCount / _durationTotalFrameCount;
-                            _currentState = KeyFramesStates.RunApplyValue;
-
-                        }
-                        break;
-
-                    case KeyFramesStates.RunBackwards:
-
-                        if (_durationFrameCount > _durationTotalFrameCount)
-                        {
-                            _currentState = KeyFramesStates.RunComplete;
-                        }
-                        else
-                        {
-                            _tempDuration = (double)(_durationTotalFrameCount - _durationFrameCount) / _durationTotalFrameCount;
-                            _currentState = KeyFramesStates.RunApplyValue;
-                        }
-                        break;
-
-                    case KeyFramesStates.RunApplyValue:
-
-                        _easedTime = _targetAnimation.Easing.Ease(_tempDuration);
-
-                        _durationFrameCount++;
-                        _lastInterpValue = Interpolator(_easedTime, _neutralValue);
-                        _targetObserver.OnNext(_lastInterpValue);
-                        _currentState = KeyFramesStates.DoRun;
-                        handled = true;
-                        break;
-
-                    case KeyFramesStates.RunComplete:
-
-                        if (_checkLoopAndRepeat)
-                        {
-                            _delayFrameCount = 0;
-                            _durationFrameCount = 0;
-
-                            if (_isLooping)
-                            {
-                                _currentState = KeyFramesStates.DoRun;
-                            }
-                            else if (_isRepeating)
-                            {
-                                if (_currentIteration >= _repeatCount)
-                                {
-                                    _currentState = KeyFramesStates.Stop;
-                                }
-                                else
-                                {
-                                    _currentState = KeyFramesStates.DoRun;
-                                }
-                                _currentIteration++;
-                            }
-
-                            if (_animationDirection == PlaybackDirection.Alternate
-                             || _animationDirection == PlaybackDirection.AlternateReverse)
-                                _isReversed = !_isReversed;
-
-                            break;
-                        }
-
-                        _currentState = KeyFramesStates.Stop;
-                        break;
-
-                    case KeyFramesStates.Stop:
-
-                        if (_fillMode == FillMode.Forward
-                         || _fillMode == FillMode.Both)
-                        {
-                            _targetControl.SetValue(_parent.Property, _lastInterpValue, BindingPriority.LocalValue);
-                        }
-
-                        _targetObserver.OnCompleted();
-                        _onComplete?.Invoke();
-                        Dispose();
-                        handled = true;
-                        break;
-                    default:
-                        handled = true;
-                        break;
-                }
-            }
-        }
-
-        public IDisposable Subscribe(IObserver<object> observer)
-        {
-            _targetObserver = observer;
-            return this;
-        }
-
-        public void Dispose()
-        {
-            _unsubscribe = true;
-            _currentState = KeyFramesStates.Disposed;
-        }
-    }
-}

src/Avalonia.Animation/Animator`1.cs

@@ -1,13 +1,10 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
-using Avalonia.Collections;
-using System.ComponentModel;
-using Avalonia.Animation.Utils;
-using System.Reactive.Linq;
 using System.Linq;
+using System.Reactive.Linq;
+using Avalonia.Animation.Utils;
+using Avalonia.Collections;
 using Avalonia.Data;
-using System.Reactive.Disposables;
 
 namespace Avalonia.Animation
 {
@@ -19,9 +16,9 @@ namespace Avalonia.Animation
         /// <summary>
         /// List of type-converted keyframes.
         /// </summary>
-        private readonly SortedList<double, (AnimatorKeyFrame, bool isNeutral)> _convertedKeyframes = new SortedList<double, (AnimatorKeyFrame, bool)>();
+        private readonly List<AnimatorKeyFrame> _convertedKeyframes = new List<AnimatorKeyFrame>();
-
+ 
-        private bool _isVerfifiedAndConverted;
+        private bool _isVerifiedAndConverted;
 
         /// <summary>
         /// Gets or sets the target property for the keyframe.
@@ -31,18 +28,17 @@ namespace Avalonia.Animation
         public Animator()
         {
             // Invalidate keyframes when changed.
-            this.CollectionChanged += delegate { _isVerfifiedAndConverted = false; };
+             this.CollectionChanged += delegate { _isVerifiedAndConverted = false; };
         }
 
         /// <inheritdoc/>
-        public virtual IDisposable Apply(Animation animation, Animatable control, IObservable<bool> obsMatch, Action onComplete)
+        public virtual IDisposable Apply(Animation animation, Animatable control, IObservable<bool> match, Action onComplete)
         {
-            if (!_isVerfifiedAndConverted)
+             if (!_isVerifiedAndConverted)
                 VerifyConvertKeyFrames();
 
-            return obsMatch
+            return match
-                // Ignore triggers when global timers are paused.
+                .Where(p => p)
-                .Where(p => p && Timing.GetGlobalPlayState() != PlayState.Pause)
                 .Subscribe(_ =>
                 {
                     var timerObs = RunKeyFrames(animation, control, onComplete);
@@ -59,53 +55,56 @@ namespace Avalonia.Animation
         /// <param name="t">The time parameter, relative to the total animation time</param>
         protected (double IntraKFTime, KeyFramePair<T> KFPair) GetKFPairAndIntraKFTime(double t)
         {
-            KeyValuePair<double, (AnimatorKeyFrame frame, bool isNeutral)> firstCue, lastCue;
+            AnimatorKeyFrame firstCue, lastCue ;
             int kvCount = _convertedKeyframes.Count;
             if (kvCount > 2)
             {
-                if (DoubleUtils.AboutEqual(t, 0.0) || t < 0.0)
+                if (t <= 0.0)
                 {
-                    firstCue = _convertedKeyframes.First();
+                    firstCue = _convertedKeyframes[0];
-                    lastCue = _convertedKeyframes.Skip(1).First();
+                    lastCue = _convertedKeyframes[1];
                 }
-                else if (DoubleUtils.AboutEqual(t, 1.0) || t > 1.0)
+                else if (t >= 1.0)
                 {
-                    firstCue = _convertedKeyframes.Skip(kvCount - 2).First();
+                    firstCue = _convertedKeyframes[_convertedKeyframes.Count - 2];
-                    lastCue = _convertedKeyframes.Last();
+                    lastCue = _convertedKeyframes[_convertedKeyframes.Count - 1];
                 }
                 else
                 {
-                    firstCue = _convertedKeyframes.Last(j => j.Key <= t);
+                    (double time, int index) maxval = (0.0d, 0);
-                    lastCue = _convertedKeyframes.First(j => j.Key >= t);
+                    for (int i = 0; i < _convertedKeyframes.Count; i++)
+                    {
+                        var comp = _convertedKeyframes[i].Cue.CueValue;
+                        if (t >= comp)
+                        {
+                            maxval = (comp, i);
+                        }
+                    }
+                    firstCue = _convertedKeyframes[maxval.index];
+                    lastCue = _convertedKeyframes[maxval.index + 1];
                 }
             }
             else
             {
-                firstCue = _convertedKeyframes.First();
+                firstCue = _convertedKeyframes[0];
-                lastCue = _convertedKeyframes.Last();
+                lastCue = _convertedKeyframes[1];
             }
 
-            double t0 = firstCue.Key;
+            double t0 = firstCue.Cue.CueValue;
-            double t1 = lastCue.Key;
+            double t1 = lastCue.Cue.CueValue;
             var intraframeTime = (t - t0) / (t1 - t0);
-            var firstFrameData = (firstCue.Value.frame.GetTypedValue<T>(), firstCue.Value.isNeutral);
+            var firstFrameData = (firstCue.GetTypedValue<T>(), firstCue.isNeutral);
-            var lastFrameData = (lastCue.Value.frame.GetTypedValue<T>(), lastCue.Value.isNeutral);
+            var lastFrameData = (lastCue.GetTypedValue<T>(), lastCue.isNeutral);
             return (intraframeTime, new KeyFramePair<T>(firstFrameData, lastFrameData));
         }
 
-
         /// <summary>
         /// Runs the KeyFrames Animation.
         /// </summary>
         private IDisposable RunKeyFrames(Animation animation, Animatable control, Action onComplete)
         {
-            var stateMachine = new AnimatorStateMachine<T>(animation, control, this, onComplete);
+            var instance = new AnimationInstance<T>(animation, control, this, onComplete, DoInterpolation);
-
+            return control.Bind<T>((AvaloniaProperty<T>)Property, instance, BindingPriority.Animation);
-            Timing.AnimationStateTimer
-                        .TakeWhile(_ => !stateMachine._unsubscribe)
-                        .Subscribe(p => stateMachine.Step(p, DoInterpolation));
-
-            return control.Bind(Property, stateMachine, BindingPriority.Animation);
         }
 
         /// <summary>
@@ -114,18 +113,26 @@ namespace Avalonia.Animation
         protected abstract T DoInterpolation(double time, T neutralValue);
 
         /// <summary>
-        /// Verifies and converts keyframe values according to this class's target type.
+        /// Verifies, converts and sorts keyframe values according to this class's target type.
         /// </summary>
         private void VerifyConvertKeyFrames()
         {
             foreach (AnimatorKeyFrame keyframe in this)
             {
-                _convertedKeyframes.Add(keyframe.Cue.CueValue, (keyframe, false));
+                _convertedKeyframes.Add(keyframe);
             }
 
             AddNeutralKeyFramesIfNeeded();
-            _isVerfifiedAndConverted = true;
 
+            var copy = _convertedKeyframes.ToList().OrderBy(p => p.Cue.CueValue);
+            _convertedKeyframes.Clear();
+
+            foreach (AnimatorKeyFrame keyframe in copy)
+            {
+                _convertedKeyframes.Add(keyframe);
+            }
+
+            _isVerifiedAndConverted = true;
         }
 
         private void AddNeutralKeyFramesIfNeeded()
@@ -133,14 +140,14 @@ namespace Avalonia.Animation
             bool hasStartKey, hasEndKey;
             hasStartKey = hasEndKey = false;
 
-            // Make start and end keyframe mandatory.
+            // Check if there's start and end keyframes.
-            foreach (var converted in _convertedKeyframes.Keys)
+            foreach (var frame in _convertedKeyframes)
             {
-                if (DoubleUtils.AboutEqual(converted, 0.0))
+                if (frame.Cue.CueValue == 0.0d)
                 {
                     hasStartKey = true;
                 }
-                else if (DoubleUtils.AboutEqual(converted, 1.0))
+                else if (frame.Cue.CueValue == 1.0d)
                 {
                     hasEndKey = true;
                 }
@@ -154,12 +161,12 @@ namespace Avalonia.Animation
         {
             if (!hasStartKey)
             {
-                _convertedKeyframes.Add(0.0d, (new AnimatorKeyFrame { Value = default(T) }, true));
+                _convertedKeyframes.Add(new AnimatorKeyFrame(null, new Cue(0.0d)) { Value = default(T), isNeutral = true });
             }
 
             if (!hasEndKey)
             {
-                _convertedKeyframes.Add(1.0d, (new AnimatorKeyFrame { Value = default(T) }, true));
+                _convertedKeyframes.Add(new AnimatorKeyFrame(null, new Cue(1.0d)) { Value = default(T), isNeutral = true });
             }
         }
     }

src/Avalonia.Animation/Cue.cs

@@ -1,13 +1,11 @@
 using System;
-using System.Collections.Generic;
 using System.ComponentModel;
 using System.Globalization;
-using System.Text;
 
 namespace Avalonia.Animation
 {
     /// <summary>
-    /// A Cue object for <see cref="KeyFrame"/>. 
+    /// Determines the time index for a <see cref="KeyFrame"/>. 
     /// </summary>
     [TypeConverter(typeof(CueTypeConverter))]
     public readonly struct Cue : IEquatable<Cue>, IEquatable<double>
@@ -84,5 +82,4 @@ namespace Avalonia.Animation
             return Cue.Parse((string)value, culture);
         }
     }
-
+}
-}

src/Avalonia.Animation/DoubleAnimator.cs

@@ -1,13 +1,4 @@
-using System;
+namespace Avalonia.Animation
-using System.Collections.Generic;
-using System.Text;
-using System.Linq;
-using System.Reactive.Linq;
-using System.Diagnostics;
-using Avalonia.Animation.Utils;
-using Avalonia.Data;
-
-namespace Avalonia.Animation
 {
     /// <summary>
     /// Animator that handles <see cref="double"/> properties.

src/Avalonia.Animation/DoubleTransition.cs

@@ -1,7 +1,6 @@
 // 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.Metadata;
 using System;
 using System.Reactive.Linq;
 

src/Avalonia.Animation/Easing/BounceEaseIn.cs

@@ -1,7 +1,6 @@
 // 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.Animation.Utils;
 
 namespace Avalonia.Animation.Easings

src/Avalonia.Animation/Easing/Easing.cs

@@ -1,10 +1,7 @@
-using Avalonia.Collections;
 using System;
 using System.Collections.Generic;
-using System.Text;
-using System.Reflection;
-using System.Linq;
 using System.ComponentModel;
+using System.Linq;
 
 namespace Avalonia.Animation.Easings
 {

src/Avalonia.Animation/Easing/EasingTypeConverter.cs

@@ -1,7 +1,6 @@
 // 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.Animation.Easings;
 using System;
 using System.ComponentModel;
 using System.Globalization;
@@ -20,4 +19,4 @@ namespace Avalonia.Animation.Easings
             return Easing.Parse((string)value);
         }
     }
-}
+}

src/Avalonia.Animation/Easing/ElasticEaseIn.cs

@@ -1,8 +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.Animation.Utils;
 using System;
+using Avalonia.Animation.Utils;
 
 namespace Avalonia.Animation.Easings
 {

src/Avalonia.Animation/Easing/ElasticEaseOut.cs

@@ -1,8 +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.Animation.Utils;
 using System;
+using Avalonia.Animation.Utils;
 
 namespace Avalonia.Animation.Easings
 {

src/Avalonia.Animation/Easing/SineEaseIn.cs

@@ -1,8 +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.Animation.Utils;
 using System;
+using Avalonia.Animation.Utils;
 
 namespace Avalonia.Animation.Easings
 {

src/Avalonia.Animation/Easing/SineEaseOut.cs

@@ -1,8 +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.Animation.Utils;
 using System;
+using Avalonia.Animation.Utils;
 
 namespace Avalonia.Animation.Easings
 {

src/Avalonia.Animation/FillMode.cs

@@ -1,8 +1,4 @@
-using System;
+namespace Avalonia.Animation
-using System.Collections.Generic;
-using System.Text;
-
-namespace Avalonia.Animation
 {
     public enum FillMode
     {

src/Avalonia.Animation/FloatTransition.cs

@@ -1,7 +1,6 @@
 // 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.Metadata;
 using System;
 using System.Reactive.Linq;
 

src/Avalonia.Animation/IAnimation.cs

@@ -1,6 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
 using System.Threading.Tasks;
 
 namespace Avalonia.Animation

src/Avalonia.Animation/IAnimator.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 
 namespace Avalonia.Animation
 {

src/Avalonia.Animation/ITransition.cs

@@ -1,9 +1,7 @@
 // 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.Metadata;
 using System;
-using System.Reactive.Linq;
 
 namespace Avalonia.Animation
 {

src/Avalonia.Animation/IntegerTransition.cs

@@ -1,7 +1,6 @@
 // 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.Metadata;
 using System;
 using System.Reactive.Linq;
 

src/Avalonia.Animation/KeyFrame.cs

@@ -1,8 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
-using System.ComponentModel;
-using Avalonia.Metadata;
 using Avalonia.Collections;
 
 namespace Avalonia.Animation

src/Avalonia.Animation/KeyFramePair`1.cs

@@ -1,14 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-using Avalonia.Collections;
-using System.ComponentModel;
-using Avalonia.Animation.Utils;
-using System.Reactive.Linq;
-using System.Linq;
-using Avalonia.Data;
-using System.Reactive.Disposables;
-
 namespace Avalonia.Animation
 {
     /// <summary>

src/Avalonia.Animation/PlayState.cs

@@ -1,8 +1,4 @@
-using System;
+namespace Avalonia.Animation
-using System.Collections.Generic;
-using System.Text;
-
-namespace Avalonia.Animation
 {
     /// <summary>
     /// Determines the playback state of an animation.
@@ -24,4 +20,4 @@ namespace Avalonia.Animation
         /// </summary>
         Stop
     }
-}
+}

src/Avalonia.Animation/PlaybackDirection.cs

@@ -1,8 +1,4 @@
-using System;
+namespace Avalonia.Animation
-using System.Collections.Generic;
-using System.Text;
-
-namespace Avalonia.Animation
 {
     /// <summary>
     /// Determines the playback direction of an animation.

src/Avalonia.Animation/RepeatCount.cs

@@ -1,12 +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.Utilities;
 using System;
-using System.Collections.Generic;
 using System.ComponentModel;
 using System.Globalization;
-using System.Linq;
 
 namespace Avalonia.Animation
 {
@@ -199,4 +196,4 @@ namespace Avalonia.Animation
             }
         }
     }
-}
+}

src/Avalonia.Animation/RepeatCountTypeConverter.cs

@@ -1,7 +1,6 @@
 // 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.Animation.Easings;
 using System;
 using System.ComponentModel;
 using System.Globalization;
@@ -20,4 +19,4 @@ namespace Avalonia.Animation
             return RepeatCount.Parse((string)value);
         }
     }
-}
+}

src/Avalonia.Animation/Timing.cs

@@ -2,10 +2,8 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
-using System.Diagnostics;
 using System.Linq;
 using System.Reactive.Linq;
-using Avalonia.Data;
 using Avalonia.Threading;
 
 namespace Avalonia.Animation
@@ -15,9 +13,6 @@ namespace Avalonia.Animation
     /// </summary>
     public static class Timing
     {
-        static ulong _transitionsFrameCount;
-        static PlayState _globalState = PlayState.Run;
-
         /// <summary>
         /// The number of frames per second.
         /// </summary>
@@ -32,41 +27,16 @@ namespace Avalonia.Animation
         /// Initializes static members of the <see cref="Timing"/> class.
         /// </summary>
         static Timing()
-        {
+        { 
             var globalTimer = Observable.Interval(FrameTick, AvaloniaScheduler.Instance);
 
-            AnimationStateTimer = globalTimer
+            AnimationsTimer = globalTimer
-                .Select(_ =>
+                .Select(_ => GetTickCount())
-                {
-                    return _globalState;
-                })
                 .Publish()
                 .RefCount();
-
-            TransitionsTimer = globalTimer
-                               .Select(p => _transitionsFrameCount++)
-                               .Publish()
-                               .RefCount();
-        }
-
-
-        /// <summary>
-        /// Sets the animation play state for all animations
-        /// </summary>
-        public static void SetGlobalPlayState(PlayState playState)
-        {
-            Dispatcher.UIThread.VerifyAccess();
-            _globalState = playState;
         }
 
-        /// <summary>
+        internal static TimeSpan GetTickCount() => TimeSpan.FromMilliseconds(Environment.TickCount);
-        /// Gets the animation play state for all animations
-        /// </summary>
-        public static PlayState GetGlobalPlayState()
-        {
-            Dispatcher.UIThread.VerifyAccess();
-            return _globalState;
-        }
 
         /// <summary>
         /// Gets the animation timer.
@@ -76,48 +46,9 @@ namespace Avalonia.Animation
         /// defined in <see cref="FramesPerSecond"/>.
         /// The parameter passed to a subsciber is the current playstate of the animation.
         /// </remarks>
-        internal static IObservable<PlayState> AnimationStateTimer
+        internal static IObservable<TimeSpan> AnimationsTimer
         {
             get;
         }
-
-        /// <summary>
-        /// Gets the transitions timer.
-        /// </summary>
-        /// <remarks>
-        /// The transitions timer increments usually 60 times per second as
-        /// defined in <see cref="FramesPerSecond"/>.
-        /// The parameter passed to a subsciber is the number of frames since the animation system was
-        /// initialized.
-        /// </remarks>
-        public static IObservable<ulong> TransitionsTimer
-        {
-            get;
-        }
-
-        /// <summary>
-        /// Gets a timer that fires every frame for the specified duration with delay.
-        /// </summary>
-        /// <returns>
-        /// An observable that notifies the subscriber of the progress along the transition.
-        /// </returns>
-        /// <remarks>
-        /// The parameter passed to the subscriber is the progress along the transition, with
-        /// 0 being the start and 1 being the end. The observable is guaranteed to fire 0
-        /// immediately on subscribe and 1 at the end of the duration.
-        /// </remarks>
-        public static IObservable<double> GetTransitionsTimer(Animatable control, TimeSpan duration, TimeSpan delay = default(TimeSpan))
-        {
-            var startTime = _transitionsFrameCount;
-            var _duration = (ulong)(duration.Ticks / FrameTick.Ticks);
-            var endTime = startTime + _duration;
-
-            return TransitionsTimer
-                .TakeWhile(x => x < endTime)
-                .Select(x => (double)(x - startTime) / _duration)
-                .StartWith(0.0)
-                .Concat(Observable.Return(1.0));
-        }
-
     }
-}
+}

src/Avalonia.Animation/TransitionInstance.cs

@@ -0,0 +1,54 @@
+// 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.Metadata;
+using System;
+using System.Reactive.Linq;
+using Avalonia.Animation.Easings;
+using Avalonia.Animation.Utils;
+using Avalonia.Reactive;
+
+namespace Avalonia.Animation
+{
+    /// <summary>
+    /// Handles the timing and lifetime of a <see cref="Transition{T}"/>.
+    /// </summary>
+    internal class TransitionInstance : SingleSubscriberObservableBase<double>
+    {
+        private IDisposable timerSubscription;
+        private TimeSpan startTime;
+        private TimeSpan duration;
+
+        public TransitionInstance(TimeSpan Duration)
+        {
+            duration = Duration;
+        }
+
+        private void TimerTick(TimeSpan t)
+        {
+            var interpVal = (double)(t.Ticks - startTime.Ticks) / duration.Ticks;
+
+            if (interpVal > 1d
+             || interpVal < 0d)
+            {
+                PublishCompleted();
+                return;
+            }
+
+            PublishNext(interpVal);
+        }
+
+        protected override void Unsubscribed()
+        {
+            timerSubscription?.Dispose();
+        }
+
+        protected override void Subscribed()
+        {
+            startTime = Timing.GetTickCount();
+            timerSubscription = Timing.AnimationsTimer
+                                      .Subscribe(t => TimerTick(t));
+            PublishNext(0.0d);
+        }
+    }
+}

src/Avalonia.Animation/Transition`1.cs

@@ -1,10 +1,10 @@
 // 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.Metadata;
 using System;
 using System.Reactive.Linq;
 using Avalonia.Animation.Easings;
+using Avalonia.Animation.Utils;
 
 namespace Avalonia.Animation
 {
@@ -24,17 +24,7 @@ namespace Avalonia.Animation
         /// <summary>
         /// Gets the easing class to be used.
         /// </summary>
-        public Easing Easing
+        public Easing Easing { get; set; } = new LinearEasing();
-        {
-            get
-            {
-                return _easing ?? (_easing = new LinearEasing());
-            }
-            set
-            {
-                _easing = value;
-            }
-        }
 
         /// <inheritdocs/>
         public AvaloniaProperty Property
@@ -61,8 +51,10 @@ namespace Avalonia.Animation
         /// <inheritdocs/>
         public virtual IDisposable Apply(Animatable control, object oldValue, object newValue)
         {
-            var transition = DoTransition(Timing.GetTransitionsTimer(control, Duration, TimeSpan.Zero), (T)oldValue, (T)newValue).Select(p => (object)p);
+            var transition = DoTransition(new TransitionInstance(Duration), (T)oldValue, (T)newValue);
-            return control.Bind(Property, transition, Data.BindingPriority.Animation);
+            return control.Bind<T>((AvaloniaProperty<T>)Property, transition, Data.BindingPriority.Animation);
         }
+
+
     }
-}
+}

src/Avalonia.Animation/Utils/DoubleUtils.cs

@@ -1,18 +0,0 @@
-// 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;
-using System.Collections.Generic;
-using System.Text;
-
-namespace Avalonia.Animation.Utils
-{
-    internal static class DoubleUtils
-    {
-        internal static bool AboutEqual(double x, double y)
-        {
-            double epsilon = Math.Max(Math.Abs(x), Math.Abs(y)) * 1E-15;
-            return Math.Abs(x - y) <= epsilon;
-        }
-    }
-}

src/Avalonia.Animation/Utils/EasingUtils.cs

@@ -13,6 +13,6 @@ namespace Avalonia.Animation.Utils
         /// <summary>
         /// Half of <see cref="Math.PI"/>
         /// </summary>
-        internal static double HALFPI = Math.PI / 2d;
+        internal const double HALFPI = Math.PI / 2d;
     }
 }

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

@@ -2,7 +2,6 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
-using Avalonia.Data;
 
 namespace Avalonia.Data.Core.Plugins
 {

src/Avalonia.Base/PriorityBindingEntry.cs

@@ -50,6 +50,11 @@ namespace Avalonia
             get;
         }
 
+        /// <summary>
+        /// Gets a value indicating whether the binding has completed.
+        /// </summary>
+        public bool HasCompleted { get; private set; }
+
         /// <summary>
         /// The current value of the binding.
         /// </summary>
@@ -129,6 +134,8 @@ namespace Avalonia
 
         private void Completed()
         {
+            HasCompleted = true;
+
             if (Dispatcher.UIThread.CheckAccess())
             {
                 _owner.Completed(this);

src/Avalonia.Base/PriorityLevel.cs

@@ -112,12 +112,16 @@ namespace Avalonia
 
             return Disposable.Create(() =>
             {
-                Bindings.Remove(node);
+                if (!entry.HasCompleted)
-                entry.Dispose();
-
-                if (entry.Index >= ActiveBindingIndex)
                 {
-                    ActivateFirstBinding();
+                    Bindings.Remove(node);
+
+                    entry.Dispose();
+
+                    if (entry.Index >= ActiveBindingIndex)
+                    {
+                        ActivateFirstBinding();
+                    }
                 }
             });
         }

src/Avalonia.Base/Threading/Dispatcher.cs

@@ -92,6 +92,20 @@ namespace Avalonia.Threading
             return _jobRunner.InvokeAsync(function, priority);
         }
 
+        /// <inheritdoc/>
+        public Task InvokeAsync(Func<Task> function, DispatcherPriority priority = DispatcherPriority.Normal)
+        {
+            Contract.Requires<ArgumentNullException>(function != null);
+            return _jobRunner.InvokeAsync(function, priority).Unwrap();
+        }
+
+        /// <inheritdoc/>
+        public Task<TResult> InvokeAsync<TResult>(Func<Task<TResult>> function, DispatcherPriority priority = DispatcherPriority.Normal)
+        {
+            Contract.Requires<ArgumentNullException>(function != null);
+            return _jobRunner.InvokeAsync(function, priority).Unwrap();
+        }
+
         /// <inheritdoc/>
         public void Post(Action action, DispatcherPriority priority = DispatcherPriority.Normal)
         {

src/Avalonia.Base/Threading/IDispatcher.cs

@@ -40,5 +40,23 @@ namespace Avalonia.Threading
         /// <param name="function">The method.</param>
         /// <param name="priority">The priority with which to invoke the method.</param>
         Task<TResult> InvokeAsync<TResult>(Func<TResult> function, DispatcherPriority priority = DispatcherPriority.Normal);
+
+        /// <summary>
+        /// Queues the specified work to run on the dispatcher thread and returns a proxy for the
+        /// task returned by <paramref name="function"/>.
+        /// </summary>
+        /// <param name="function">The work to execute asynchronously.</param>
+        /// <param name="priority">The priority with which to invoke the method.</param>
+        /// <returns>A task that represents a proxy for the task returned by <paramref name="function"/>.</returns>
+        Task InvokeAsync(Func<Task> function, DispatcherPriority priority = DispatcherPriority.Normal);
+
+        /// <summary>
+        /// Queues the specified work to run on the dispatcher thread and returns a proxy for the
+        /// task returned by <paramref name="function"/>.
+        /// </summary>
+        /// <param name="function">The work to execute asynchronously.</param>
+        /// <param name="priority">The priority with which to invoke the method.</param>
+        /// <returns>A task that represents a proxy for the task returned by <paramref name="function"/>.</returns>
+        Task<TResult> InvokeAsync<TResult>(Func<Task<TResult>> function, DispatcherPriority priority = DispatcherPriority.Normal);
     }
 }

src/Avalonia.Controls/Border.cs

@@ -43,8 +43,12 @@ namespace Avalonia.Controls
         /// </summary>
         static Border()
         {
-            AffectsRender(BackgroundProperty, BorderBrushProperty, BorderThicknessProperty, CornerRadiusProperty);
+            AffectsRender<Border>(
-            AffectsMeasure(BorderThicknessProperty);
+                BackgroundProperty,
+                BorderBrushProperty,
+                BorderThicknessProperty,
+                CornerRadiusProperty);
+            AffectsMeasure<Border>(BorderThicknessProperty);
         }
 
         /// <summary>

src/Avalonia.Controls/Button.cs

@@ -80,7 +80,7 @@ namespace Avalonia.Controls
             FocusableProperty.OverrideDefaultValue(typeof(Button), true);
             CommandProperty.Changed.Subscribe(CommandChanged);
             IsDefaultProperty.Changed.Subscribe(IsDefaultChanged);
-            PseudoClass(IsPressedProperty, ":pressed");
+            PseudoClass<Button>(IsPressedProperty, ":pressed");
         }
 
         /// <summary>

src/Avalonia.Controls/ButtonSpinner.cs

@@ -85,8 +85,8 @@ namespace Avalonia.Controls
         static ButtonSpinner()
         {
             AllowSpinProperty.Changed.Subscribe(AllowSpinChanged);
-            PseudoClass(ButtonSpinnerLocationProperty, location => location == Location.Left, ":left");
+            PseudoClass<ButtonSpinner, Location>(ButtonSpinnerLocationProperty, location => location == Location.Left, ":left");
-            PseudoClass(ButtonSpinnerLocationProperty, location => location == Location.Right, ":right");
+            PseudoClass<ButtonSpinner, Location>(ButtonSpinnerLocationProperty, location => location == Location.Right, ":right");
         }
 
         /// <summary>
@@ -260,4 +260,4 @@ namespace Avalonia.Controls
             }
         }
     }
-}
+}

src/Avalonia.Controls/Canvas.cs

@@ -48,7 +48,7 @@ namespace Avalonia.Controls
         static Canvas()
         {
             ClipToBoundsProperty.OverrideDefaultValue<Canvas>(false);
-            AffectsCanvasArrange(LeftProperty, TopProperty, RightProperty, BottomProperty);
+            AffectsParentArrange<Canvas>(LeftProperty, TopProperty, RightProperty, BottomProperty);
         }
 
         /// <summary>
@@ -207,29 +207,5 @@ namespace Avalonia.Controls
 
             return finalSize;
         }
-
-        /// <summary>
-        /// Marks a property on a child as affecting the canvas' arrangement.
-        /// </summary>
-        /// <param name="properties">The properties.</param>
-        private static void AffectsCanvasArrange(params AvaloniaProperty[] properties)
-        {
-            foreach (var property in properties)
-            {
-                property.Changed.Subscribe(AffectsCanvasArrangeInvalidate);
-            }
-        }
-
-        /// <summary>
-        /// Calls <see cref="Layoutable.InvalidateArrange"/> on the parent of the control whose
-        /// property changed, if that parent is a canvas.
-        /// </summary>
-        /// <param name="e">The event args.</param>
-        private static void AffectsCanvasArrangeInvalidate(AvaloniaPropertyChangedEventArgs e)
-        {
-            var control = e.Sender as IControl;
-            var canvas = control?.VisualParent as Canvas;
-            canvas?.InvalidateArrange();
-        }
     }
 }

src/Avalonia.Controls/ContentControl.cs

@@ -45,6 +45,8 @@ namespace Avalonia.Controls
         static ContentControl()
         {
             ContentControlMixin.Attach<ContentControl>(ContentProperty, x => x.LogicalChildren);
+            PseudoClass<ContentControl, object>(ContentProperty, x => x != null, ":valid");
+            PseudoClass<ContentControl, object>(ContentProperty, x => x == null, ":invalid");
         }
 
         /// <summary>

src/Avalonia.Controls/Converters/MarginMultiplierConverter.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Globalization;
+using Avalonia.Data.Converters;
+
+namespace Avalonia.Controls.Converters
+{
+    public class MarginMultiplierConverter : IValueConverter
+    {
+        public double Indent { get; set; }
+
+        public bool Left { get; set; } = false;
+
+        public bool Top { get; set; } = false;
+
+        public bool Right { get; set; } = false;
+
+        public bool Bottom { get; set; } = false;
+
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            if (!(value is int depth))
+                return new Thickness(0);
+
+            return new Thickness(Left ? Indent * depth : 0, Top ? Indent * depth : 0, Right ? Indent * depth : 0, Bottom ? Indent * depth : 0);
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new System.NotImplementedException();
+        }
+    }
+}

src/Avalonia.Controls/Decorator.cs

@@ -28,7 +28,7 @@ namespace Avalonia.Controls
         /// </summary>
         static Decorator()
         {
-            AffectsMeasure(ChildProperty, PaddingProperty);
+            AffectsMeasure<Decorator>(ChildProperty, PaddingProperty);
             ChildProperty.Changed.AddClassHandler<Decorator>(x => x.ChildChanged);
         }
 

src/Avalonia.Controls/DockPanel.cs

@@ -37,7 +37,7 @@ namespace Avalonia.Controls
         /// </summary>
         static DockPanel()
         {
-            AffectsArrange(DockProperty);
+            AffectsParentMeasure<DockPanel>(DockProperty);
         }
 
         /// <summary>
@@ -173,4 +173,4 @@ namespace Avalonia.Controls
             return arrangeSize;
         }
     }
-}
+}

src/Avalonia.Controls/DrawingPresenter.cs

@@ -8,8 +8,8 @@ namespace Avalonia.Controls
     {
         static DrawingPresenter()
         {
-            AffectsMeasure(DrawingProperty);
+            AffectsMeasure<DrawingPresenter>(DrawingProperty);
-            AffectsRender(DrawingProperty);
+            AffectsRender<DrawingPresenter>(DrawingProperty);
         }
 
         public static readonly StyledProperty<Drawing> DrawingProperty =
@@ -49,11 +49,11 @@ namespace Avalonia.Controls
             if (Drawing != null)
             {
                 using (context.PushPreTransform(_transform))
-                using (context.PushClip(Bounds))
+                using (context.PushClip(new Rect(Bounds.Size)))
                 {
                     Drawing.Draw(context);
                 }
             }
         }
     }
-}
+}

src/Avalonia.Controls/Expander.cs

@@ -35,12 +35,12 @@ namespace Avalonia.Controls
 
         static Expander()
         {
-            PseudoClass(ExpandDirectionProperty, d => d == ExpandDirection.Down, ":down");
+            PseudoClass<Expander, ExpandDirection>(ExpandDirectionProperty, d => d == ExpandDirection.Down, ":down");
-            PseudoClass(ExpandDirectionProperty, d => d == ExpandDirection.Up, ":up");
+            PseudoClass<Expander, ExpandDirection>(ExpandDirectionProperty, d => d == ExpandDirection.Up, ":up");
-            PseudoClass(ExpandDirectionProperty, d => d == ExpandDirection.Left, ":left");
+            PseudoClass<Expander, ExpandDirection>(ExpandDirectionProperty, d => d == ExpandDirection.Left, ":left");
-            PseudoClass(ExpandDirectionProperty, d => d == ExpandDirection.Right, ":right");
+            PseudoClass<Expander, ExpandDirection>(ExpandDirectionProperty, d => d == ExpandDirection.Right, ":right");
 
-            PseudoClass(IsExpandedProperty, ":expanded");
+            PseudoClass<Expander>(IsExpandedProperty, ":expanded");
 
             IsExpandedProperty.Changed.AddClassHandler<Expander>(x => x.OnIsExpandedChanged);
         }

src/Avalonia.Controls/Grid.cs

@@ -48,6 +48,11 @@ namespace Avalonia.Controls
 
         private RowDefinitions _rowDefinitions;
 
+        static Grid()
+        {
+            AffectsParentMeasure<Grid>(ColumnProperty, ColumnSpanProperty, RowProperty, RowSpanProperty);
+        }
+
         /// <summary>
         /// Gets or sets the columns definitions for the grid.
         /// </summary>

src/Avalonia.Controls/Image.cs

@@ -25,8 +25,7 @@ namespace Avalonia.Controls
 
         static Image()
         {
-            AffectsRender(SourceProperty);
+            AffectsRender<Image>(SourceProperty, StretchProperty);
-            AffectsRender(StretchProperty);
         }
 
         /// <summary>

src/Avalonia.Controls/MenuItem.cs

@@ -99,6 +99,7 @@ namespace Avalonia.Controls
             SelectableMixin.Attach<MenuItem>(IsSelectedProperty);
             CommandProperty.Changed.Subscribe(CommandChanged);
             FocusableProperty.OverrideDefaultValue<MenuItem>(true);
+            HeaderProperty.Changed.AddClassHandler<MenuItem>(x => x.HeaderChanged);
             IconProperty.Changed.AddClassHandler<MenuItem>(x => x.IconChanged);
             IsSelectedProperty.Changed.AddClassHandler<MenuItem>(x => x.IsSelectedChanged);
             ItemsPanelProperty.OverrideDefaultValue<MenuItem>(DefaultPanel);
@@ -357,10 +358,21 @@ namespace Avalonia.Controls
         {
             base.OnTemplateApplied(e);
 
-            _popup = e.NameScope.Get<Popup>("PART_Popup");
+            if (_popup != null)
-            _popup.DependencyResolver = DependencyResolver.Instance;
+            {
-            _popup.Opened += PopupOpened;
+                _popup.Opened -= PopupOpened;
-            _popup.Closed += PopupClosed;
+                _popup.Closed -= PopupClosed;
+                _popup.DependencyResolver = null;
+            }
+
+            _popup = e.NameScope.Find<Popup>("PART_Popup");
+
+            if (_popup != null)
+            {
+                _popup.DependencyResolver = DependencyResolver.Instance;
+                _popup.Opened += PopupOpened;
+                _popup.Closed += PopupClosed;
+            }
         }
 
         /// <summary>
@@ -408,6 +420,24 @@ namespace Avalonia.Controls
             IsEnabled = Command == null || Command.CanExecute(CommandParameter);
         }
 
+        /// <summary>
+        /// Called when the <see cref="Header"/> property changes.
+        /// </summary>
+        /// <param name="e">The property change event.</param>
+        private void HeaderChanged(AvaloniaPropertyChangedEventArgs e)
+        {
+            if (e.NewValue is string newValue && newValue == "-")
+            {
+                PseudoClasses.Add(":separator");
+                Focusable = false;
+            }
+            else if (e.OldValue is string oldValue && oldValue == "-")
+            {
+                PseudoClasses.Remove(":separator");
+                Focusable = true;
+            }
+        }
+
         /// <summary>
         /// Called when the <see cref="Icon"/> property changes.
         /// </summary>

src/Avalonia.Controls/Panel.cs

@@ -30,6 +30,7 @@ namespace Avalonia.Controls
         /// </summary>
         static Panel()
         {
+            AffectsRender<Panel>(BackgroundProperty);
             ClipToBoundsProperty.OverrideDefaultValue<Panel>(true);
         }
 
@@ -72,6 +73,32 @@ namespace Avalonia.Controls
             base.Render(context);
         }
 
+        /// <summary>
+        /// Marks a property on a child as affecting the parent panel's arrangement.
+        /// </summary>
+        /// <param name="properties">The properties.</param>
+        protected static void AffectsParentArrange<TPanel>(params AvaloniaProperty[] properties)
+            where TPanel : class, IPanel
+        {
+            foreach (var property in properties)
+            {
+                property.Changed.Subscribe(AffectsParentArrangeInvalidate<TPanel>);
+            }
+        }
+
+        /// <summary>
+        /// Marks a property on a child as affecting the parent panel's measurement.
+        /// </summary>
+        /// <param name="properties">The properties.</param>
+        protected static void AffectsParentMeasure<TPanel>(params AvaloniaProperty[] properties)
+            where TPanel : class, IPanel
+        {
+            foreach (var property in properties)
+            {
+                property.Changed.Subscribe(AffectsParentMeasureInvalidate<TPanel>);
+            }
+        }
+
         /// <summary>
         /// Called when the <see cref="Children"/> collection changes.
         /// </summary>
@@ -116,5 +143,21 @@ namespace Avalonia.Controls
 
             InvalidateMeasure();
         }
+
+        private static void AffectsParentArrangeInvalidate<TPanel>(AvaloniaPropertyChangedEventArgs e)
+            where TPanel : class, IPanel
+        {
+            var control = e.Sender as IControl;
+            var panel = control?.VisualParent as TPanel;
+            panel?.InvalidateArrange();
+        }
+
+        private static void AffectsParentMeasureInvalidate<TPanel>(AvaloniaPropertyChangedEventArgs e)
+            where TPanel : class, IPanel
+        {
+            var control = e.Sender as IControl;
+            var panel = control?.VisualParent as TPanel;
+            panel?.InvalidateMeasure();
+        }
     }
 }

src/Avalonia.Controls/Presenters/ContentPresenter.cs

@@ -90,8 +90,8 @@ namespace Avalonia.Controls.Presenters
         /// </summary>
         static ContentPresenter()
         {
-            AffectsRender(BackgroundProperty, BorderBrushProperty, BorderThicknessProperty, CornerRadiusProperty);
+            AffectsRender<ContentPresenter>(BackgroundProperty, BorderBrushProperty, BorderThicknessProperty, CornerRadiusProperty);
-            AffectsMeasure(BorderThicknessProperty, PaddingProperty);
+            AffectsMeasure<ContentPresenter>(BorderThicknessProperty, PaddingProperty);
             ContentProperty.Changed.AddClassHandler<ContentPresenter>(x => x.ContentChanged);
             ContentTemplateProperty.Changed.AddClassHandler<ContentPresenter>(x => x.ContentChanged);
             TemplatedParentProperty.Changed.AddClassHandler<ContentPresenter>(x => x.TemplatedParentChanged);

src/Avalonia.Controls/Presenters/ItemVirtualizer.cs

@@ -279,6 +279,6 @@ namespace Avalonia.Controls.Presenters
         /// <summary>
         /// Invalidates the current scroll.
         /// </summary>
-        protected void InvalidateScroll() => ((ILogicalScrollable)Owner).InvalidateScroll();
+        protected void InvalidateScroll() => ((ILogicalScrollable)Owner).InvalidateScroll?.Invoke();
     }
 }

src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs

@@ -72,7 +72,7 @@ namespace Avalonia.Controls.Presenters
         {
             ClipToBoundsProperty.OverrideDefaultValue(typeof(ScrollContentPresenter), true);
             ChildProperty.Changed.AddClassHandler<ScrollContentPresenter>(x => x.ChildChanged);
-            AffectsArrange(OffsetProperty);
+            AffectsArrange<ScrollContentPresenter>(OffsetProperty);
         }
 
         /// <summary>

src/Avalonia.Controls/Presenters/TextPresenter.cs

@@ -35,6 +35,11 @@ namespace Avalonia.Controls.Presenters
         private int _selectionEnd;
         private bool _caretBlink;
         private IBrush _highlightBrush;
+        
+        static TextPresenter()
+        {
+            AffectsRender<TextPresenter>(PasswordCharProperty);
+        }
 
         public TextPresenter()
         {
@@ -49,6 +54,9 @@ namespace Avalonia.Controls.Presenters
 
             this.GetObservable(CaretIndexProperty)
                 .Subscribe(CaretIndexChanged);
+
+            this.GetObservable(PasswordCharProperty)
+                .Subscribe(_ => InvalidateFormattedText());
         }
 
         public int CaretIndex

src/Avalonia.Controls/Primitives/AccessText.cs

@@ -28,7 +28,7 @@ namespace Avalonia.Controls.Primitives
         /// </summary>
         static AccessText()
         {
-            AffectsRender(ShowAccessKeyProperty);
+            AffectsRender<AccessText>(ShowAccessKeyProperty);
         }
 
         /// <summary>

src/Avalonia.Controls/Primitives/ScrollBar.cs

@@ -54,8 +54,8 @@ namespace Avalonia.Controls.Primitives
         /// </summary>
         static ScrollBar()
         {
-            PseudoClass(OrientationProperty, o => o == Orientation.Vertical, ":vertical");
+            PseudoClass<ScrollBar, Orientation>(OrientationProperty, o => o == Orientation.Vertical, ":vertical");
-            PseudoClass(OrientationProperty, o => o == Orientation.Horizontal, ":horizontal");
+            PseudoClass<ScrollBar, Orientation>(OrientationProperty, o => o == Orientation.Horizontal, ":horizontal");
 
             Thumb.DragDeltaEvent.AddClassHandler<ScrollBar>(o => o.OnThumbDragDelta, RoutingStrategies.Bubble);
             Thumb.DragCompletedEvent.AddClassHandler<ScrollBar>(o => o.OnThumbDragComplete, RoutingStrategies.Bubble);

src/Avalonia.Controls/Primitives/ToggleButton.cs

@@ -24,9 +24,9 @@ namespace Avalonia.Controls.Primitives
 
         static ToggleButton()
         {
-            PseudoClass(IsCheckedProperty, c => c == true, ":checked");
+            PseudoClass<ToggleButton, bool?>(IsCheckedProperty, c => c == true, ":checked");
-            PseudoClass(IsCheckedProperty, c => c == false, ":unchecked");
+            PseudoClass<ToggleButton, bool?>(IsCheckedProperty, c => c == false, ":unchecked");
-            PseudoClass(IsCheckedProperty, c => c == null, ":indeterminate");
+            PseudoClass<ToggleButton, bool?>(IsCheckedProperty, c => c == null, ":indeterminate");
         }
 
         public bool? IsChecked

src/Avalonia.Controls/Primitives/Track.cs

@@ -39,10 +39,12 @@ namespace Avalonia.Controls.Primitives
 
         static Track()
         {
+            PseudoClass<Track, Orientation>(OrientationProperty, o => o == Orientation.Vertical, ":vertical");
+            PseudoClass<Track, Orientation>(OrientationProperty, o => o == Orientation.Horizontal, ":horizontal");
             ThumbProperty.Changed.AddClassHandler<Track>(x => x.ThumbChanged);
             IncreaseButtonProperty.Changed.AddClassHandler<Track>(x => x.ButtonChanged);
             DecreaseButtonProperty.Changed.AddClassHandler<Track>(x => x.ButtonChanged);
-            AffectsArrange(MinimumProperty, MaximumProperty, ValueProperty, OrientationProperty);
+            AffectsArrange<Track>(MinimumProperty, MaximumProperty, ValueProperty, OrientationProperty);
         }
 
         public double Minimum

src/Avalonia.Controls/ProgressBar.cs

@@ -33,9 +33,9 @@ namespace Avalonia.Controls
 
         static ProgressBar()
         {
-            PseudoClass(OrientationProperty, o => o == Avalonia.Controls.Orientation.Vertical, ":vertical");
+            PseudoClass<ProgressBar, Orientation>(OrientationProperty, o => o == Avalonia.Controls.Orientation.Vertical, ":vertical");
-            PseudoClass(OrientationProperty, o => o == Avalonia.Controls.Orientation.Horizontal, ":horizontal");
+            PseudoClass<ProgressBar, Orientation>(OrientationProperty, o => o == Avalonia.Controls.Orientation.Horizontal, ":horizontal");
-            PseudoClass(IsIndeterminateProperty, ":indeterminate");
+            PseudoClass<ProgressBar>(IsIndeterminateProperty, ":indeterminate");
 
             ValueProperty.Changed.AddClassHandler<ProgressBar>(x => x.ValueChanged);
         }

src/Avalonia.Controls/Shapes/Shape.cs

@@ -30,11 +30,10 @@ namespace Avalonia.Controls.Shapes
         private Geometry _renderedGeometry;
         bool _calculateTransformOnArrange = false;
 
-
         static Shape()
         {
-            AffectsMeasure(StretchProperty, StrokeThicknessProperty);
+            AffectsMeasure<Shape>(StretchProperty, StrokeThicknessProperty);
-            AffectsRender(FillProperty, StrokeProperty, StrokeDashArrayProperty);
+            AffectsRender<Shape>(FillProperty, StrokeProperty, StrokeDashArrayProperty);
         }
 
         public Geometry DefiningGeometry

src/Avalonia.Controls/Slider.cs

@@ -42,6 +42,8 @@ namespace Avalonia.Controls
         static Slider()
         {
             OrientationProperty.OverrideDefaultValue(typeof(Slider), Orientation.Horizontal);
+            PseudoClass<Slider, Orientation>(OrientationProperty, o => o == Orientation.Vertical, ":vertical");
+            PseudoClass<Slider, Orientation>(OrientationProperty, o => o == Orientation.Horizontal, ":horizontal");
             Thumb.DragStartedEvent.AddClassHandler<Slider>(x => x.OnThumbDragStarted, RoutingStrategies.Bubble);
             Thumb.DragDeltaEvent.AddClassHandler<Slider>(x => x.OnThumbDragDelta, RoutingStrategies.Bubble);
             Thumb.DragCompletedEvent.AddClassHandler<Slider>(x => x.OnThumbDragCompleted, RoutingStrategies.Bubble);
@@ -171,11 +173,7 @@ namespace Avalonia.Controls
         /// <param name="value">Value that want to snap to closest Tick.</param>
         private void MoveToNextTick(double value)
         {
-            double next = SnapToTick(Math.Max(Minimum, Math.Min(Maximum, value)));
+            Value = SnapToTick(Math.Max(Minimum, Math.Min(Maximum, value)));
-            if (next != value)
-            {
-                Value = next;
-            }
         }
 
         /// <summary>
@@ -194,4 +192,4 @@ namespace Avalonia.Controls
             return value;
         }
     }
-}
+}

src/Avalonia.Controls/StackPanel.cs

@@ -29,8 +29,8 @@ namespace Avalonia.Controls
         /// </summary>
         static StackPanel()
         {
-            AffectsMeasure(SpacingProperty);
+            AffectsMeasure<StackPanel>(SpacingProperty);
-            AffectsMeasure(OrientationProperty);
+            AffectsMeasure<StackPanel>(OrientationProperty);
         }
 
         /// <summary>

src/Avalonia.Controls/TabControl.cs

@@ -44,7 +44,7 @@ namespace Avalonia.Controls
         {
             SelectionModeProperty.OverrideDefaultValue<TabControl>(SelectionMode.AlwaysSelected);
             FocusableProperty.OverrideDefaultValue<TabControl>(false);
-            AffectsMeasure(TabStripPlacementProperty);
+            AffectsMeasure<TabControl>(TabStripPlacementProperty);
         }
 
         /// <summary>

src/Avalonia.Controls/TextBlock.cs

@@ -6,6 +6,7 @@ using System.Reactive;
 using System.Reactive.Linq;
 using Avalonia.LogicalTree;
 using Avalonia.Media;
+using Avalonia.Media.Immutable;
 using Avalonia.Metadata;
 
 namespace Avalonia.Controls
@@ -65,7 +66,7 @@ namespace Avalonia.Controls
         public static readonly AttachedProperty<IBrush> ForegroundProperty =
             AvaloniaProperty.RegisterAttached<TextBlock, Control, IBrush>(
                 nameof(Foreground),
-                new SolidColorBrush(0xff000000),
+                Brushes.Black,
                 inherits: true);
 
         /// <summary>
@@ -99,10 +100,12 @@ namespace Avalonia.Controls
         static TextBlock()
         {
             ClipToBoundsProperty.OverrideDefaultValue<TextBlock>(true);
-            AffectsRender(ForegroundProperty);
+            AffectsRender<TextBlock>(
-            AffectsRender(FontWeightProperty);
+                BackgroundProperty,
-            AffectsRender(FontSizeProperty);
+                ForegroundProperty,
-            AffectsRender(FontStyleProperty);
+                FontWeightProperty,
+                FontSizeProperty,
+                FontStyleProperty);
         }
 
         /// <summary>

src/Avalonia.Controls/TopLevel.cs

@@ -59,7 +59,7 @@ namespace Avalonia.Controls
         /// </summary>
         static TopLevel()
         {
-            AffectsMeasure(ClientSizeProperty);
+            AffectsMeasure<TopLevel>(ClientSizeProperty);
         }
 
         /// <summary>

src/Avalonia.Controls/TreeView.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 System;
+using System.Collections.Generic;
 using System.Linq;
 using Avalonia.Controls.Generators;
 using Avalonia.Controls.Primitives;
@@ -31,6 +33,14 @@ namespace Avalonia.Controls
                 o => o.SelectedItem,
                 (o, v) => o.SelectedItem = v);
 
+        /// <summary>
+        /// Defines the <see cref="SelectedItemChanged"/> event.
+        /// </summary>
+        public static readonly RoutedEvent<SelectionChangedEventArgs> SelectedItemChangedEvent =
+            RoutedEvent.Register<TreeView, SelectionChangedEventArgs>(
+                "SelectedItemChanged",
+                RoutingStrategies.Bubble);
+
         private object _selectedItem;
 
         /// <summary>
@@ -41,6 +51,15 @@ namespace Avalonia.Controls
             // HACK: Needed or SelectedItem property will not be found in Release build.
         }
 
+        /// <summary>
+        /// Occurs when the control's selection changes.
+        /// </summary>
+        public event EventHandler<SelectionChangedEventArgs> SelectedItemChanged
+        {
+            add { AddHandler(SelectedItemChangedEvent, value); }
+            remove { RemoveHandler(SelectedItemChangedEvent, value); }
+        }
+
         /// <summary>
         /// Gets the <see cref="ITreeItemContainerGenerator"/> for the tree view.
         /// </summary>
@@ -74,6 +93,7 @@ namespace Avalonia.Controls
                     MarkContainerSelected(container, false);
                 }
 
+                var oldItem = _selectedItem;
                 SetAndRaise(SelectedItemProperty, ref _selectedItem, value);
 
                 if (_selectedItem != null)
@@ -86,6 +106,28 @@ namespace Avalonia.Controls
                         container.BringIntoView();
                     }
                 }
+
+                if (oldItem != _selectedItem)
+                {
+                    // Fire the SelectionChanged event
+                    List<object> removed = new List<object>();
+                    if (oldItem != null)
+                    {
+                        removed.Add(oldItem);
+                    }
+
+                    List<object> added = new List<object>();
+                    if (_selectedItem != null)
+                    {
+                        added.Add(_selectedItem);
+                    }
+
+                    var changed = new SelectionChangedEventArgs(
+                        SelectedItemChangedEvent,
+                        added,
+                        removed);
+                    RaiseEvent(changed);
+                }
             }
         }
 

src/Avalonia.Controls/TreeViewItem.cs

@@ -21,7 +21,7 @@ namespace Avalonia.Controls
         /// </summary>
         public static readonly DirectProperty<TreeViewItem, bool> IsExpandedProperty =
             AvaloniaProperty.RegisterDirect<TreeViewItem, bool>(
-                "IsExpanded",
+                nameof(IsExpanded),
                 o => o.IsExpanded,
                 (o, v) => o.IsExpanded = v);
 
@@ -31,17 +31,25 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<bool> IsSelectedProperty =
             ListBoxItem.IsSelectedProperty.AddOwner<TreeViewItem>();
 
+        /// <summary>
+        /// Defines the <see cref="Level"/> property.
+        /// </summary>
+        public static readonly DirectProperty<TreeViewItem, int> LevelProperty =
+            AvaloniaProperty.RegisterDirect<TreeViewItem, int>(
+                nameof(Level), o => o.Level);
+
         private static readonly ITemplate<IPanel> DefaultPanel =
             new FuncTemplate<IPanel>(() => new StackPanel());
 
         private TreeView _treeView;
         private bool _isExpanded;
+        private int _level;
 
         /// <summary>
         /// Initializes static members of the <see cref="TreeViewItem"/> class.
         /// </summary>
         static TreeViewItem()
-        {            
+        {
             SelectableMixin.Attach<TreeViewItem>(IsSelectedProperty);
             FocusableProperty.OverrideDefaultValue<TreeViewItem>(true);
             ItemsPanelProperty.OverrideDefaultValue<TreeViewItem>(DefaultPanel);
@@ -65,6 +73,15 @@ namespace Avalonia.Controls
             set { SetValue(IsSelectedProperty, value); }
         }
 
+        /// <summary>
+        /// Gets the level/indentation of the item.
+        /// </summary>
+        public int Level
+        {
+            get { return _level; }
+            private set { SetAndRaise(LevelProperty, ref _level, value); }
+        }
+
         /// <summary>
         /// Gets the <see cref="ITreeItemContainerGenerator"/> for the tree view.
         /// </summary>
@@ -89,6 +106,8 @@ namespace Avalonia.Controls
             base.OnAttachedToLogicalTree(e);
             _treeView = this.GetLogicalAncestors().OfType<TreeView>().FirstOrDefault();
 
+            Level = CalculateDistanceFromLogicalParent<TreeView>(this) - 1;
+
             if (ItemTemplate == null && _treeView?.ItemTemplate != null)
             {
                 ItemTemplate = _treeView.ItemTemplate;
@@ -126,5 +145,18 @@ namespace Avalonia.Controls
 
             // Don't call base.OnKeyDown - let events bubble up to containing TreeView.
         }
+
+        private static int CalculateDistanceFromLogicalParent<T>(ILogical logical, int @default = -1) where T : class
+        {
+            var result = 0;
+
+            while (logical != null && logical.GetType() != typeof(T))
+            {
+                ++result;
+                logical = logical.LogicalParent;
+            }
+
+            return logical != null ? result : @default;
+        }
     }
 }