WIP of new overlapped drawing

Terminal.Gui/Application/Application.Run.cs

@@ -461,10 +461,8 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             {
                 v.LayoutSubviews ();
             }
-            if (v.Visible)
+            if (v.Visible && (v.NeedsDisplay || v.SubViewNeedsDisplay))
             {
-                v.SetNeedsDisplay ();
-                v.SetSubViewNeedsDisplay ();
                 v.Draw ();
             }
         }
@@ -622,9 +620,9 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         if (TopLevels.Count > 0)
         {
             Top = TopLevels.Peek ();
+            Top.SetNeedsDisplay ();
         }
 
-        // BUGBUG: We should not call OnEnter/OnLeave directly; they should only be called by SetHasFocus
         if (runState.Toplevel is { HasFocus: true })
         {
             runState.Toplevel.HasFocus = false;
@@ -635,8 +633,6 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             Top.SetFocus ();
         }
 
-        //Refresh ();
-
         _cachedRunStateToplevel = runState.Toplevel;
 
         runState.Toplevel = null;

Terminal.Gui/View/View.Drawing.cs

@@ -478,7 +478,7 @@ public partial class View // Drawing APIs
                 return;
             }
 
-            if (SuperView is { })
+            if (SuperView is { } || this == Application.Top)
             {
                 Clear ();
             }

Terminal.Gui/View/View.Layout.cs

@@ -768,8 +768,17 @@ public partial class View // Layout APIs
             LayoutAdornments ();
         }
 
-        SetNeedsDisplay ();
         SetNeedsLayout ();
+
+        SetNeedsDisplay ();
+        foreach (Toplevel v in Application.TopLevels)
+        {
+            if (v.Visible && (v != this))
+            {
+                v.SetNeedsDisplay ();
+            }
+        }
+
     }
 
     internal bool LayoutNeeded { get; private set; } = true;

Terminal.Gui/Views/Toplevel.cs

@@ -245,35 +245,35 @@ public partial class Toplevel : View
 
     #region Draw
 
-    /// <inheritdoc/>
-    public override void OnDrawContent (Rectangle viewport)
-    {
-        if (!Visible)
-        {
-            return;
-        }
+    ///// <inheritdoc/>
+    //public override void OnDrawContent (Rectangle viewport)
+    //{
+    //    if (!Visible)
+    //    {
+    //        return;
+    //    }
 
-        if (NeedsDisplay || SubViewNeedsDisplay /*|| LayoutNeeded*/)
-        {
-            Clear ();
+    //    if (NeedsDisplay || SubViewNeedsDisplay /*|| LayoutNeeded*/)
+    //    {
+    //        Clear ();
 
-            //LayoutSubviews ();
-            //PositionToplevels ();
+    //        //LayoutSubviews ();
+    //        //PositionToplevels ();
             
-            // BUGBUG: This appears to be a hack to get ScrollBarViews to render correctly.
-            foreach (View view in Subviews)
-            {
-                if (view.Frame.IntersectsWith (Viewport) && !OutsideTopFrame (this))
-                {
-                    //view.SetNeedsLayout ();
-                    view.SetNeedsDisplay ();
-                    view.SetSubViewNeedsDisplay ();
-                }
-            }
+    //        // BUGBUG: This appears to be a hack to get ScrollBarViews to render correctly.
+    //        foreach (View view in Subviews)
+    //        {
+    //            if (view.Frame.IntersectsWith (Viewport) && !OutsideTopFrame (this))
+    //            {
+    //                //view.SetNeedsLayout ();
+    //                view.SetNeedsDisplay ();
+    //                view.SetSubViewNeedsDisplay ();
+    //            }
+    //        }
 
-            base.OnDrawContent (viewport);
-        }
-    }
+    //        base.OnDrawContent (viewport);
+    //    }
+    //}
 
     #endregion
 
@@ -443,42 +443,3 @@ public class ToplevelEqualityComparer : IEqualityComparer<Toplevel>
         return hCode.GetHashCode ();
     }
 }
-
-/// <summary>
-///     Implements the <see cref="IComparer{T}"/> to sort the <see cref="Toplevel"/> from the
-///     <see cref="ApplicationOverlapped.OverlappedChildren"/> if needed.
-/// </summary>
-public sealed class ToplevelComparer : IComparer<Toplevel>
-{
-    /// <summary>
-    ///     Compares two objects and returns a value indicating whether one is less than, equal to, or greater than the
-    ///     other.
-    /// </summary>
-    /// <param name="x">The first object to compare.</param>
-    /// <param name="y">The second object to compare.</param>
-    /// <returns>
-    ///     A signed integer that indicates the relative values of <paramref name="x"/> and <paramref name="y"/>, as shown
-    ///     in the following table.Value Meaning Less than zero <paramref name="x"/> is less than <paramref name="y"/>.Zero
-    ///     <paramref name="x"/> equals <paramref name="y"/> .Greater than zero <paramref name="x"/> is greater than
-    ///     <paramref name="y"/>.
-    /// </returns>
-    public int Compare (Toplevel? x, Toplevel? y)
-    {
-        if (ReferenceEquals (x, y))
-        {
-            return 0;
-        }
-
-        if (x is null)
-        {
-            return -1;
-        }
-
-        if (y is null)
-        {
-            return 1;
-        }
-
-        return string.CompareOrdinal (x.Id, y.Id);
-    }
-}