Moved CreateGraphcsDevice and InvokePaint implementations to RenderWindowBase

UIX.RenderApi.Skia/Microsoft/Iris/Render/RenderWindowBase.cs

@@ -1,4 +1,6 @@
 using Microsoft.Iris.Input;
+using Microsoft.Iris.Library;
+using Microsoft.Iris.Render.Common;
 using Microsoft.Iris.Render.Graphics;
 using Microsoft.Iris.Render.Internal;
 using System;
@@ -7,10 +9,24 @@ namespace Microsoft.Iris.Render
 {
     public abstract class RenderWindowBase : IRenderWindow, ITreeOwner
     {
-        internal abstract GraphicsDevice CreateGraphicsDevice(
+        private RenderSession m_session;
+        private GraphicsDevice m_graphicsDevice;
+        private IVisualContainer m_visualRoot;
+
+        internal virtual GraphicsDevice CreateGraphicsDevice(
           RenderSession session,
           GraphicsDeviceType graphicsDeviceType,
-          GraphicsRenderingQuality renderingQuality);
+          GraphicsRenderingQuality renderingQuality)
+        {
+            m_session = session;
+            if (graphicsDeviceType.FulfillsRequirement(GraphicsDeviceType.Skia))
+                m_graphicsDevice = new SkiaGraphicsDevice(session);
+
+            m_visualRoot = new VisualContainer(true, session, this, new Object(), out var visual);
+            InvokePaint();
+
+            return GraphicsDevice;
+        }
 
         public abstract int Left { get; }
         public abstract int Top { get; }
@@ -40,7 +56,7 @@ namespace Microsoft.Iris.Render
         public abstract WindowState WindowState { get; set; }
         public abstract FormStyleInfo Styles { get; set; }
         public abstract HWND AppNotifyWindow { set; }
-        public abstract IVisualContainer VisualRoot { get; }
+        public virtual IVisualContainer VisualRoot => m_visualRoot;
         TreeNode ITreeOwner.Root { get; }
         public bool CatchCloseRequests => CloseRequestEvent != null;
 
@@ -58,9 +74,9 @@ namespace Microsoft.Iris.Render
 
         internal abstract ColorF OutlineMarkedColor { get; set; }
 
-        internal abstract GraphicsDevice GraphicsDevice { get; }
+        internal virtual GraphicsDevice GraphicsDevice => m_graphicsDevice;
 
-        internal abstract RenderSession Session { get; }
+        internal virtual RenderSession Session => m_session;
 
         internal abstract GraphicsDeviceType GraphicsDeviceType { get; }
 
@@ -119,5 +135,17 @@ namespace Microsoft.Iris.Render
         protected virtual void OnClose() => CloseEvent?.Invoke();
         protected virtual void OnCloseRequest() => CloseRequestEvent?.Invoke();
         protected virtual void OnSetFocus(bool focused) => SetFocusEvent?.Invoke(focused);
+        
+        public virtual void InvokePaint()
+        {
+            Session?.DeferredInvoke(new DeferredHandler((obj) =>
+            {
+                Debug2.WriteLine(DebugCategory.FormWindow, 0, (string)obj);
+            }), "Howdy from dispatcher!", DeferredInvokePriority.VisualUpdate);
+            return;
+
+            var surface = Session.EngineInfo.Surface;
+            surface.Canvas.DrawText("Howdy from UIX in WPF!", 0, 0, new SkiaSharp.SKPaint(new SkiaSharp.SKFont(SkiaSharp.SKTypeface.Default)));
+        }
     }
 }

UIX.RenderApi.Skia/Microsoft/Iris/Render/WpfRenderWindow.WPF.cs

@@ -22,6 +22,7 @@ namespace Microsoft.Iris.Render
         private GraphicsDevice graphicsDevice;
         private HWND appNotifyWindow;
         private IVisualContainer visualRoot;
+        private RenderSession session;
 
         private Window WpfWindow { get; set; }
         private WindowInteropHelper InteropHelper { get; set; }
@@ -42,19 +43,6 @@ namespace Microsoft.Iris.Render
             WpfWindow.Loaded += WpfWindow_Loaded;
         }
 
-        internal override GraphicsDevice CreateGraphicsDevice(
-          RenderSession session,
-          GraphicsDeviceType graphicsDeviceType,
-          GraphicsRenderingQuality renderingQuality)
-        {
-            if (graphicsDeviceType.FulfillsRequirement(GraphicsDeviceType.Skia))
-                graphicsDevice = new SkiaGraphicsDevice(session);
-
-            visualRoot = new VisualContainer(true, session, this, new Object(), out var visual);
-
-            return GraphicsDevice;
-        }
-
         public override int Left => (int)WpfWindow.Left;
 
         public override int Top => (int)WpfWindow.Top;
@@ -201,15 +189,12 @@ namespace Microsoft.Iris.Render
             {
                 WpfWindow.Dispatcher.Invoke(() =>
                 {
-                    if (WpfWindow.Content is Control ctl)
+                    WpfWindow.Background = new SolidColorBrush(Color.FromArgb(
-                    {
-                        ctl.Background = new SolidColorBrush(Color.FromArgb(
                         (byte)(value.A * 255),
                         (byte)(value.R * 255),
                         (byte)(value.G * 255),
                         (byte)(value.B * 255)
                     ));
-                    }
                 });
             }
         }
@@ -298,8 +283,6 @@ namespace Microsoft.Iris.Render
         }
         public override HWND AppNotifyWindow { set => appNotifyWindow = value; }
 
-        public override IVisualContainer VisualRoot => visualRoot;
-
         TreeNode Root => throw new NotImplementedException();
 
         private bool _IsClosing = false;
@@ -316,10 +299,6 @@ namespace Microsoft.Iris.Render
         internal override ColorF OutlineAllColor { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
         internal override ColorF OutlineMarkedColor { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
 
-        internal override GraphicsDevice GraphicsDevice => graphicsDevice;
-
-        internal override RenderSession Session => throw new NotImplementedException();
-
         internal override GraphicsDeviceType GraphicsDeviceType => GraphicsDeviceType.Skia;
 
         internal override bool IsRightToLeft => CultureInfo.CurrentCulture.TextInfo.IsRightToLeft;

UIX.Skia/Microsoft/Iris/Session/UIDispatcher.cs

@@ -206,6 +206,9 @@ namespace Microsoft.Iris.Session
 
         private PriorityQueue.HookProc GetQueueDrainHook(DispatchPriority priority) => _masterQueue.GetDrainHook((int)priority);
 
+        /// <summary>
+        /// Creates a <see cref="MessageLoop"/> and starts handling items in <paramref name="queue"/>.
+        /// </summary>
         private void MainLoop(Queue queue, LoopCondition condition)
         {
             using (new UIDispatcher.MessageLoop(this, condition))

UIX.Skia/Microsoft/Iris/Session/UISession.cs

@@ -51,12 +51,7 @@ namespace Microsoft.Iris.Session
         {
         }
 
-        public UISession(
+        public UISession(SKSurface skSurface, RenderWindowBase renderWindow, EventHandler rendererConnectedCallback, TimeoutHandler handlerTimeout, uint timeoutSecValue)
-            SKSurface skSurface,
-            RenderWindowBase renderWindow,
-            EventHandler rendererConnectedCallback,
-            TimeoutHandler handlerTimeout,
-          uint timeoutSecValue)
         {
             _syncWindowHandler = new SimpleCallback(SyncWindowHandler);
             _queueSyncLayoutComplete = new SimpleQueue();