Tons of Layout refactoring. LayoutSubviews is now internal.

UnitTests/View/Adornment/BorderTests.cs

@@ -96,7 +96,7 @@ public class BorderTests (ITestOutputHelper output)
         var firstIteration = false;
 
         ((FakeDriver)Application.Driver!).SetBufferSize (width, 5);
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, firstIteration);
         var expected = string.Empty;
 
         switch (width)
@@ -227,10 +227,9 @@ public class BorderTests (ITestOutputHelper output)
         win.Border.Thickness = win.Border.Thickness with { Top = 3 };
 
         RunState rs = Application.Begin (win);
-        var firstIteration = false;
 
         ((FakeDriver)Application.Driver!).SetBufferSize (width, 4);
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, false);
         var expected = string.Empty;
 
         switch (width)
@@ -364,7 +363,7 @@ public class BorderTests (ITestOutputHelper output)
         var firstIteration = false;
 
         ((FakeDriver)Application.Driver!).SetBufferSize (width, 4);
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, firstIteration);
         var expected = string.Empty;
 
         switch (width)
@@ -487,7 +486,7 @@ public class BorderTests (ITestOutputHelper output)
         var firstIteration = false;
 
         ((FakeDriver)Application.Driver!).SetBufferSize (20, height);
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, firstIteration);
         var expected = string.Empty;
 
         switch (height)
@@ -549,7 +548,7 @@ public class BorderTests (ITestOutputHelper output)
         var firstIteration = false;
 
         ((FakeDriver)Application.Driver!).SetBufferSize (width, 3);
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, firstIteration);
         var expected = string.Empty;
 
         switch (width)
@@ -729,7 +728,7 @@ public class BorderTests (ITestOutputHelper output)
         var firstIteration = false;
 
         ((FakeDriver)Application.Driver!).SetBufferSize (5, 5);
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, firstIteration);
 
         var expected = @"
 ╔═══╗
@@ -757,7 +756,7 @@ public class BorderTests (ITestOutputHelper output)
         var firstIteration = false;
 
         ((FakeDriver)Application.Driver!).SetBufferSize (10, 4);
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, firstIteration);
 
         var expected = @"
 ╔════════╗
@@ -780,7 +779,7 @@ public class BorderTests (ITestOutputHelper output)
         var firstIteration = false;
 
         ((FakeDriver)Application.Driver!).SetBufferSize (3, 3);
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, firstIteration);
 
         var expected = @"
 ┌─┐

UnitTests/View/DrawTests.cs

@@ -7,6 +7,139 @@ namespace Terminal.Gui.ViewTests;
 [Trait ("Category", "Output")]
 public class DrawTests (ITestOutputHelper _output)
 {
+    [Fact]
+    public void NeedsDisplay_True_After_Constructor ()
+    {
+        var view = new View { Width = 2, Height = 2, BorderStyle = LineStyle.Single };
+        Assert.True (view.NeedsDisplay);
+    }
+
+    [Fact]
+    public void NeedsDisplay_False_After_BeginInit ()
+    {
+        var view = new View { Width = 2, Height = 2, BorderStyle = LineStyle.Single };
+        Assert.True (view.NeedsDisplay);
+
+        view.BeginInit ();
+        Assert.True (view.NeedsDisplay);
+
+        view.NeedsDisplay = false;
+
+        view.BeginInit ();
+        Assert.False (view.NeedsDisplay);
+    }
+
+    [Fact]
+    public void NeedsDisplay_False_After_EndInit ()
+    {
+        var view = new View { Width = 2, Height = 2, BorderStyle = LineStyle.Single };
+        Assert.True (view.NeedsDisplay);
+
+        view.BeginInit ();
+        Assert.True (view.NeedsDisplay);
+
+        view.EndInit ();
+        Assert.True (view.NeedsDisplay);
+
+        view = new View { Width = 2, Height = 2, BorderStyle = LineStyle.Single };
+        view.BeginInit ();
+        view.NeedsDisplay = false;
+        view.EndInit ();
+        Assert.False (view.NeedsDisplay);
+    }
+
+    [Fact]
+    public void NeedsDisplay_False_After_SetRelativeLayout ()
+    {
+        var view = new View { Width = 2, Height = 2 };
+        Assert.True (view.NeedsDisplay);
+
+        view.BeginInit ();
+        Assert.True (view.NeedsDisplay);
+
+        view.EndInit ();
+        Assert.True (view.NeedsDisplay);
+
+        view.SetRelativeLayout (Application.Screen.Size);
+        Assert.True (view.NeedsDisplay);
+
+        view.NeedsDisplay = false;
+        view.SetRelativeLayout (new (10, 10));
+        Assert.False (view.NeedsDisplay);
+
+        view = new View { Width = Dim.Percent(50), Height = Dim.Percent(50) };
+        View superView = new ()
+        {
+            Id = "superView",
+            Width = Dim.Fill(),
+            Height = Dim.Fill()
+        };
+        superView.Add (view);
+
+        superView.BeginInit ();
+        Assert.True (view.NeedsDisplay);
+        Assert.True (superView.NeedsDisplay);
+
+        superView.EndInit ();
+        Assert.True (view.NeedsDisplay);
+        Assert.True (superView.NeedsDisplay);
+
+        superView.SetRelativeLayout (Application.Screen.Size);
+        Assert.True (view.NeedsDisplay);
+        Assert.True (superView.NeedsDisplay);
+
+        superView.NeedsDisplay = false;
+        superView.SetRelativeLayout (new (10, 10));
+        Assert.False (superView.NeedsDisplay);
+        Assert.False (view.NeedsDisplay);
+
+        view.SetRelativeLayout (new (11, 11));
+        Assert.True (superView.NeedsDisplay);
+        Assert.True (view.NeedsDisplay);
+
+    }
+
+    [Fact]
+    public void NeedsDisplay_True_After_LayoutSubviews ()
+    {
+        var view = new View { Width = 2, Height = 2, BorderStyle = LineStyle.Single };
+        Assert.True (view.NeedsDisplay);
+
+        view.BeginInit ();
+        Assert.True (view.NeedsDisplay);
+
+        view.EndInit ();
+        Assert.True (view.NeedsDisplay);
+
+        view.SetRelativeLayout (Application.Screen.Size);
+        Assert.True (view.NeedsDisplay);
+
+        view.LayoutSubviews ();
+        Assert.True (view.NeedsDisplay);
+    }
+
+    [Fact]
+    public void NeedsDisplay_False_After_Draw ()
+    {
+        var view = new View { Width = 2, Height = 2, BorderStyle = LineStyle.Single };
+        Assert.True (view.NeedsDisplay);
+
+        view.BeginInit ();
+        Assert.True (view.NeedsDisplay);
+
+        view.EndInit ();
+        Assert.True (view.NeedsDisplay);
+
+        view.SetRelativeLayout (Application.Screen.Size);
+        Assert.True (view.NeedsDisplay);
+
+        view.LayoutSubviews ();
+        Assert.True (view.NeedsDisplay);
+
+        view.Draw ();
+        Assert.False (view.NeedsDisplay);
+    }
+
     [Fact]
     [SetupFakeDriver]
     public void Move_Is_Constrained_To_Viewport ()
@@ -17,18 +150,18 @@ public class DrawTests (ITestOutputHelper _output)
             Y = 1,
             Width = 3, Height = 3
         };
-        view.Margin.Thickness = new Thickness (1);
+        view.Margin.Thickness = new (1);
 
         // Only valid location w/in Viewport is 0, 0 (view) - 2, 2 (screen)
 
         view.Move (0, 0);
-        Assert.Equal (new Point (2, 2), new Point (Application.Driver!.Col, Application.Driver!.Row));
+        Assert.Equal (new (2, 2), new Point (Application.Driver!.Col, Application.Driver!.Row));
 
         view.Move (-1, -1);
-        Assert.Equal (new Point (2, 2), new Point (Application.Driver!.Col, Application.Driver!.Row));
+        Assert.Equal (new (2, 2), new Point (Application.Driver!.Col, Application.Driver!.Row));
 
         view.Move (1, 1);
-        Assert.Equal (new Point (2, 2), new Point (Application.Driver!.Col, Application.Driver!.Row));
+        Assert.Equal (new (2, 2), new Point (Application.Driver!.Col, Application.Driver!.Row));
     }
 
     [Fact]
@@ -41,7 +174,7 @@ public class DrawTests (ITestOutputHelper _output)
             Y = 1,
             Width = 3, Height = 3
         };
-        view.Margin.Thickness = new Thickness (1);
+        view.Margin.Thickness = new (1);
         View.Diagnostics = ViewDiagnosticFlags.Padding;
         view.BeginInit ();
         view.EndInit ();
@@ -84,6 +217,7 @@ public class DrawTests (ITestOutputHelper _output)
         superView.LayoutSubviews ();
 
         superView.Draw ();
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -93,6 +227,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         Rectangle toFill = new (x, y, width, height);
         view.FillRect (toFill);
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -103,6 +238,7 @@ public class DrawTests (ITestOutputHelper _output)
         // Now try to clear beyond Viewport (invalid; clipping should prevent)
         superView.SetNeedsDisplay ();
         superView.Draw ();
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -111,6 +247,7 @@ public class DrawTests (ITestOutputHelper _output)
                                                       _output);
         toFill = new (-width, -height, width, height);
         view.FillRect (toFill);
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -121,6 +258,7 @@ public class DrawTests (ITestOutputHelper _output)
         // Now try to clear beyond Viewport (valid)
         superView.SetNeedsDisplay ();
         superView.Draw ();
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -129,6 +267,7 @@ public class DrawTests (ITestOutputHelper _output)
                                                       _output);
         toFill = new (-1, -1, width + 1, height + 1);
         view.FillRect (toFill);
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -139,6 +278,7 @@ public class DrawTests (ITestOutputHelper _output)
         // Now clear too much size
         superView.SetNeedsDisplay ();
         superView.Draw ();
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -147,6 +287,7 @@ public class DrawTests (ITestOutputHelper _output)
                                                       _output);
         toFill = new (0, 0, width * 2, height * 2);
         view.FillRect (toFill);
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -174,6 +315,7 @@ public class DrawTests (ITestOutputHelper _output)
         superView.LayoutSubviews ();
 
         superView.Draw ();
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -182,6 +324,7 @@ public class DrawTests (ITestOutputHelper _output)
                                                       _output);
 
         view.Clear ();
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -210,6 +353,7 @@ public class DrawTests (ITestOutputHelper _output)
         superView.LayoutSubviews ();
 
         superView.Draw ();
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -218,6 +362,7 @@ public class DrawTests (ITestOutputHelper _output)
                                                       _output);
 
         view.Clear ();
+
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
  ┌─┐
@@ -226,7 +371,6 @@ public class DrawTests (ITestOutputHelper _output)
                                                       _output);
     }
 
-
     [Fact]
     [AutoInitShutdown]
     [Trait ("Category", "Unicode")]
@@ -243,7 +387,7 @@ public class DrawTests (ITestOutputHelper _output)
         Assert.Equal (2, r.GetColumns ());
 
         var win = new Window { Title = us };
-        var view = new View { Text = r.ToString (), Height = Dim.Fill (), Width = Dim.Fill ()};
+        var view = new View { Text = r.ToString (), Height = Dim.Fill (), Width = Dim.Fill () };
         var tf = new TextField { Text = us, Y = 1, Width = 3 };
         win.Add (view, tf);
         Toplevel top = new ();
@@ -317,7 +461,7 @@ public class DrawTests (ITestOutputHelper _output)
                                       """;
 
         Rectangle pos = TestHelpers.AssertDriverContentsWithFrameAre (expectedOutput, _output);
-        Assert.Equal (new Rectangle (0, 0, 30, 10), pos);
+        Assert.Equal (new (0, 0, 30, 10), pos);
 
         Application.End (rsDiag);
         dg.Dispose ();
@@ -352,12 +496,13 @@ public class DrawTests (ITestOutputHelper _output)
         Toplevel top = new ();
         top.Add (viewRight, viewBottom);
 
-        Application.Begin (top);
+        var rs = Application.Begin (top);
         ((FakeDriver)Application.Driver!).SetBufferSize (7, 7);
+        Application.RunIteration (ref rs);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                         Test
                                                             
                                                             
@@ -391,13 +536,25 @@ public class DrawTests (ITestOutputHelper _output)
     public void Draw_Minimum_Full_Border_With_Empty_Viewport ()
     {
         var view = new View { Width = 2, Height = 2, BorderStyle = LineStyle.Single };
+        Assert.True (view.NeedsDisplay);
+
         view.BeginInit ();
+        Assert.True (view.NeedsDisplay);
+
         view.EndInit ();
+        Assert.True (view.NeedsDisplay);
+
         view.SetRelativeLayout (Application.Screen.Size);
+        Assert.True (view.NeedsDisplay);
+
+        view.LayoutSubviews ();
+        Assert.True (view.NeedsDisplay);
 
         Assert.Equal (new (0, 0, 2, 2), view.Frame);
         Assert.Equal (Rectangle.Empty, view.Viewport);
 
+        Assert.True (view.NeedsDisplay);
+
         view.Draw ();
 
         TestHelpers.AssertDriverContentsWithFrameAre (
@@ -415,7 +572,7 @@ public class DrawTests (ITestOutputHelper _output)
     public void Draw_Minimum_Full_Border_With_Empty_Viewport_Without_Bottom ()
     {
         var view = new View { Width = 2, Height = 1, BorderStyle = LineStyle.Single };
-        view.Border.Thickness = new Thickness (1, 1, 1, 0);
+        view.Border.Thickness = new (1, 1, 1, 0);
         view.BeginInit ();
         view.EndInit ();
         view.SetRelativeLayout (Application.Screen.Size);
@@ -433,7 +590,7 @@ public class DrawTests (ITestOutputHelper _output)
     public void Draw_Minimum_Full_Border_With_Empty_Viewport_Without_Left ()
     {
         var view = new View { Width = 1, Height = 2, BorderStyle = LineStyle.Single };
-        view.Border.Thickness = new Thickness (0, 1, 1, 1);
+        view.Border.Thickness = new (0, 1, 1, 1);
         view.BeginInit ();
         view.EndInit ();
         view.SetRelativeLayout (Application.Screen.Size);
@@ -458,7 +615,7 @@ public class DrawTests (ITestOutputHelper _output)
     public void Draw_Minimum_Full_Border_With_Empty_Viewport_Without_Right ()
     {
         var view = new View { Width = 1, Height = 2, BorderStyle = LineStyle.Single };
-        view.Border.Thickness = new Thickness (1, 1, 0, 1);
+        view.Border.Thickness = new (1, 1, 0, 1);
         view.BeginInit ();
         view.EndInit ();
         view.SetRelativeLayout (Application.Screen.Size);
@@ -483,7 +640,7 @@ public class DrawTests (ITestOutputHelper _output)
     public void Draw_Minimum_Full_Border_With_Empty_Viewport_Without_Top ()
     {
         var view = new View { Width = 2, Height = 1, BorderStyle = LineStyle.Single };
-        view.Border.Thickness = new Thickness (1, 0, 1, 1);
+        view.Border.Thickness = new (1, 0, 1, 1);
 
         view.BeginInit ();
         view.EndInit ();
@@ -494,7 +651,8 @@ public class DrawTests (ITestOutputHelper _output)
 
         view.Draw ();
 
-        TestHelpers.AssertDriverContentsWithFrameAre ("││",
+        TestHelpers.AssertDriverContentsWithFrameAre (
+                                                      "││",
                                                       _output
                                                      );
     }
@@ -510,40 +668,40 @@ public class DrawTests (ITestOutputHelper _output)
             Width = 1,
             Height = 7,
             Text = """
-            s
-            u
-            b
-            V
-            i
-            e
-            w
-            """
+                   s
+                   u
+                   b
+                   V
+                   i
+                   e
+                   w
+                   """
         };
 
         var view = new View
         {
             Id = "view", Width = 2, Height = 20, Text = """
-            0
-            1
-            2
-            3
-            4
-            5
-            6
-            7
-            8
-            9
-            0
-            1
-            2
-            3
-            4
-            5
-            6
-            7
-            8
-            9
-            """
+                                                        0
+                                                        1
+                                                        2
+                                                        3
+                                                        4
+                                                        5
+                                                        6
+                                                        7
+                                                        8
+                                                        9
+                                                        0
+                                                        1
+                                                        2
+                                                        3
+                                                        4
+                                                        5
+                                                        6
+                                                        7
+                                                        8
+                                                        9
+                                                        """
         };
         view.Add (subView);
         var content = new View { Id = "content", Width = 20, Height = 20 };
@@ -560,12 +718,12 @@ public class DrawTests (ITestOutputHelper _output)
         container.Add (content);
         Toplevel top = new ();
         top.Add (container);
-        Application.Driver!.Clip = container.Frame;
-        Application.Begin (top);
+        var rs = Application.Begin (top);
 
+        top.Draw ();
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        0s
                                                        1u
                                                        2b
@@ -580,7 +738,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        s
                                                        u
                                                        b
@@ -600,7 +758,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        1u
                                                        2b
                                                        3V
@@ -615,7 +773,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        6w
                                                        7 
                                                        8 
@@ -630,7 +788,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        9
                                                       """,
                                                       _output
@@ -682,9 +840,10 @@ public class DrawTests (ITestOutputHelper _output)
         top.LayoutComplete += Top_LayoutComplete;
         Application.Begin (top);
 
+        Application.Refresh ();
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        01234
                                                        subVi
                                                       """,
@@ -696,7 +855,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        12345
                                                        ubVie
                                                       """,
@@ -708,7 +867,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        ubVie
                                                       """,
                                                       _output
@@ -766,12 +925,12 @@ public class DrawTests (ITestOutputHelper _output)
         container.Add (content);
         Toplevel top = new ();
         top.Add (container);
-        Application.Driver!.Clip = container.Frame;
         Application.Begin (top);
 
+        Application.Refresh ();
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        0s
                                                        1u
                                                        2b
@@ -786,7 +945,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        s
                                                        u
                                                        b
@@ -806,7 +965,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        1u
                                                        2b
                                                        3V
@@ -821,7 +980,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        6w
                                                        7 
                                                        8 
@@ -836,7 +995,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
-
+                                                      
                                                        9
                                                       """,
                                                       _output
@@ -892,15 +1051,16 @@ public class DrawTests (ITestOutputHelper _output)
 
         var expected = """
 
-            ┌┤𝔹├─────┐
-            │𝔹       │
-            │𝔹       │
-            └────────┘
-            """;
+                       ┌┤𝔹├─────┐
+                       │𝔹       │
+                       │𝔹       │
+                       └────────┘
+                       """;
         TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);
 
         TestHelpers.AssertDriverContentsAre (expected, _output);
         top.Dispose ();
+
         // This test has nothing to do with color - removing as it is not relevant and fragile
     }
 
@@ -916,15 +1076,16 @@ public class DrawTests (ITestOutputHelper _output)
         // Visible content is (1, 1, 10, 10)
         // Expected clip is (1, 1, 10, 10) - same as visible content
         Rectangle expectedClip = new (1, 1, 10, 10);
+
         // Arrange
-        var view = new View ()
+        var view = new View
         {
             Width = Dim.Fill (),
             Height = Dim.Fill (),
             ViewportSettings = ViewportSettings.ClipContentOnly
         };
         view.SetContentSize (new Size (10, 10));
-        view.Border.Thickness = new Thickness (1);
+        view.Border.Thickness = new (1);
         view.BeginInit ();
         view.EndInit ();
         Assert.Equal (view.Frame, Application.Driver?.Clip);
@@ -949,14 +1110,15 @@ public class DrawTests (ITestOutputHelper _output)
         // Visible content is (1, 1, 10, 10)
         // Expected clip is (1, 1, 23, 23) - same as Viewport
         Rectangle expectedClip = new (1, 1, 23, 23);
+
         // Arrange
-        var view = new View ()
+        var view = new View
         {
             Width = Dim.Fill (),
-            Height = Dim.Fill (),
+            Height = Dim.Fill ()
         };
         view.SetContentSize (new Size (10, 10));
-        view.Border.Thickness = new Thickness (1);
+        view.Border.Thickness = new (1);
         view.BeginInit ();
         view.EndInit ();
         Assert.Equal (view.Frame, Application.Driver?.Clip);
@@ -970,7 +1132,6 @@ public class DrawTests (ITestOutputHelper _output)
         view.Dispose ();
     }
 
-
     [Fact]
     [TestRespondersDisposed]
     public void Draw_Throws_IndexOutOfRangeException_With_Negative_Bounds ()
@@ -983,11 +1144,11 @@ public class DrawTests (ITestOutputHelper _output)
         top.Add (view);
 
         Application.Iteration += (s, a) =>
-        {
-            Assert.Equal (-2, view.X);
+                                 {
+                                     Assert.Equal (-2, view.X);
 
-            Application.RequestStop ();
-        };
+                                     Application.RequestStop ();
+                                 };
 
         try
         {
@@ -1000,8 +1161,8 @@ public class DrawTests (ITestOutputHelper _output)
         }
 
         top.Dispose ();
+
         // Shutdown must be called to safely clean up Application if Init has been called
         Application.Shutdown ();
     }
-
 }

UnitTests/View/Layout/AbsoluteLayoutTests.cs

@@ -1,236 +0,0 @@
-using Xunit.Abstractions;
-
-namespace Terminal.Gui.LayoutTests;
-
-public class AbsoluteLayoutTests (ITestOutputHelper output)
-{
-    private readonly ITestOutputHelper _output = output;
-
-    [Fact]
-    [TestRespondersDisposed]
-    public void AbsoluteLayout_Change_Height_or_Width_Absolute ()
-    {
-        var frame = new Rectangle (1, 2, 3, 4);
-        var newFrame = new Rectangle (1, 2, 30, 40);
-
-        var v = new View { Frame = frame };
-        v.Height = newFrame.Height;
-        v.Width = newFrame.Width;
-        Assert.Equal (newFrame, v.Frame);
-
-        Assert.Equal (
-                      new (0, 0, newFrame.Width, newFrame.Height),
-                      v.Viewport
-                     ); // With Absolute Viewport *is* deterministic before Layout
-        Assert.Equal (Pos.Absolute (1), v.X);
-        Assert.Equal (Pos.Absolute (2), v.Y);
-        Assert.Equal ($"Absolute({newFrame.Height})", v.Height.ToString ());
-        Assert.Equal ($"Absolute({newFrame.Width})", v.Width.ToString ());
-        v.Dispose ();
-    }
-
-    [Fact]
-    [TestRespondersDisposed]
-    public void AbsoluteLayout_Change_Height_or_Width_MakesComputed ()
-    {
-        var v = new View { Frame = Rectangle.Empty };
-        v.Height = Dim.Fill ();
-        v.Width = Dim.Fill ();
-        v.Dispose ();
-    }
-
-    [Fact]
-    [TestRespondersDisposed]
-    public void AbsoluteLayout_Change_X_or_Y_Absolute ()
-    {
-        var frame = new Rectangle (1, 2, 3, 4);
-        var newFrame = new Rectangle (10, 20, 3, 4);
-
-        var v = new View { Frame = frame };
-        v.X = newFrame.X;
-        v.Y = newFrame.Y;
-        Assert.Equal (newFrame, v.Frame);
-
-        Assert.Equal (
-                      new (0, 0, newFrame.Width, newFrame.Height),
-                      v.Viewport
-                     ); // With Absolute Viewport *is* deterministic before Layout
-        Assert.Equal ($"Absolute({newFrame.X})", v.X.ToString ());
-        Assert.Equal ($"Absolute({newFrame.Y})", v.Y.ToString ());
-        Assert.Equal (Dim.Absolute (3), v.Width);
-        Assert.Equal (Dim.Absolute (4), v.Height);
-        v.Dispose ();
-    }
-
-    [Fact]
-    [TestRespondersDisposed]
-    public void AbsoluteLayout_Change_X_or_Y_MakesComputed ()
-    {
-        var v = new View { Frame = Rectangle.Empty };
-        v.X = Pos.Center ();
-        v.Y = Pos.Center ();
-        v.Dispose ();
-    }
-
-    [Fact]
-    [TestRespondersDisposed]
-    public void AbsoluteLayout_Change_X_Y_Height_Width_Absolute ()
-    {
-        var v = new View { Frame = Rectangle.Empty };
-        v.X = 1;
-        v.Y = 2;
-        v.Height = 3;
-        v.Width = 4;
-        v.Dispose ();
-
-        v = new() { Frame = Rectangle.Empty };
-        v.X = Pos.Center ();
-        v.Y = Pos.Center ();
-        v.Width = Dim.Fill ();
-        v.Height = Dim.Fill ();
-        v.Dispose ();
-
-        v = new() { Frame = Rectangle.Empty };
-        v.X = Pos.Center ();
-        v.Y = Pos.Center ();
-        v.Width = Dim.Fill ();
-        v.Height = Dim.Fill ();
-
-        v.X = 1;
-        v.Dispose ();
-
-        v = new() { Frame = Rectangle.Empty };
-        v.X = Pos.Center ();
-        v.Y = Pos.Center ();
-        v.Width = Dim.Fill ();
-        v.Height = Dim.Fill ();
-
-        v.Y = 2;
-        v.Dispose ();
-
-        v = new() { Frame = Rectangle.Empty };
-        v.X = Pos.Center ();
-        v.Y = Pos.Center ();
-        v.Width = Dim.Fill ();
-        v.Height = Dim.Fill ();
-
-        v.Width = 3;
-        v.Dispose ();
-
-        v = new() { Frame = Rectangle.Empty };
-        v.X = Pos.Center ();
-        v.Y = Pos.Center ();
-        v.Width = Dim.Fill ();
-        v.Height = Dim.Fill ();
-
-        v.Height = 3;
-        v.Dispose ();
-
-        v = new() { Frame = Rectangle.Empty };
-        v.X = Pos.Center ();
-        v.Y = Pos.Center ();
-        v.Width = Dim.Fill ();
-        v.Height = Dim.Fill ();
-
-        v.X = 1;
-        v.Y = 2;
-        v.Height = 3;
-        v.Width = 4;
-        v.Dispose ();
-    }
-
-    [Fact]
-    [TestRespondersDisposed]
-    public void AbsoluteLayout_Constructor ()
-    {
-        var v = new View ();
-        v.Dispose ();
-
-        var frame = Rectangle.Empty;
-        v = new() { Frame = frame };
-        Assert.Equal (frame, v.Frame);
-
-        Assert.Equal (
-                      new (0, 0, frame.Width, frame.Height),
-                      v.Viewport
-                     ); // With Absolute Viewport *is* deterministic before Layout
-        Assert.Equal (Pos.Absolute (0), v.X);
-        Assert.Equal (Pos.Absolute (0), v.Y);
-        Assert.Equal (Dim.Absolute (0), v.Width);
-        Assert.Equal (Dim.Absolute (0), v.Height);
-        v.Dispose ();
-
-        frame = new (1, 2, 3, 4);
-        v = new() { Frame = frame };
-        Assert.Equal (frame, v.Frame);
-
-        Assert.Equal (
-                      new (0, 0, frame.Width, frame.Height),
-                      v.Viewport
-                     ); // With Absolute Viewport *is* deterministic before Layout
-        Assert.Equal (Pos.Absolute (1), v.X);
-        Assert.Equal (Pos.Absolute (2), v.Y);
-        Assert.Equal (Dim.Absolute (3), v.Width);
-        Assert.Equal (Dim.Absolute (4), v.Height);
-        v.Dispose ();
-
-        v = new() { Frame = frame, Text = "v" };
-        Assert.Equal (frame, v.Frame);
-
-        Assert.Equal (
-                      new (0, 0, frame.Width, frame.Height),
-                      v.Viewport
-                     ); // With Absolute Viewport *is* deterministic before Layout
-        Assert.Equal (Pos.Absolute (1), v.X);
-        Assert.Equal (Pos.Absolute (2), v.Y);
-        Assert.Equal (Dim.Absolute (3), v.Width);
-        Assert.Equal (Dim.Absolute (4), v.Height);
-        v.Dispose ();
-
-        v = new() { X = frame.X, Y = frame.Y, Text = "v" };
-
-        Assert.Equal (new (frame.X, frame.Y, 0, 0), v.Frame);
-        Assert.Equal (new (0, 0, 0, 0), v.Viewport); // With Absolute Viewport *is* deterministic before Layout
-        Assert.Equal (Pos.Absolute (1), v.X);
-        Assert.Equal (Pos.Absolute (2), v.Y);
-        Assert.Equal (Dim.Absolute (0), v.Width);
-        Assert.Equal (Dim.Absolute (0), v.Height);
-        v.Dispose ();
-
-        v = new ();
-        Assert.Equal (new (0, 0, 0, 0), v.Frame);
-        Assert.Equal (new (0, 0, 0, 0), v.Viewport); // With Absolute Viewport *is* deterministic before Layout
-        Assert.Equal (Pos.Absolute (0), v.X);
-        Assert.Equal (Pos.Absolute (0), v.Y);
-        Assert.Equal (Dim.Absolute (0), v.Width);
-        Assert.Equal (Dim.Absolute (0), v.Height);
-        v.Dispose ();
-
-        v = new() { X = frame.X, Y = frame.Y, Width = frame.Width, Height = frame.Height };
-        Assert.Equal (new (frame.X, frame.Y, 3, 4), v.Frame);
-        Assert.Equal (new (0, 0, 3, 4), v.Viewport); // With Absolute Viewport *is* deterministic before Layout
-        Assert.Equal (Pos.Absolute (1), v.X);
-        Assert.Equal (Pos.Absolute (2), v.Y);
-        Assert.Equal (Dim.Absolute (3), v.Width);
-        Assert.Equal (Dim.Absolute (4), v.Height);
-        v.Dispose ();
-    }
-
-    [Fact]
-    [TestRespondersDisposed]
-    public void AbsoluteLayout_LayoutSubviews ()
-    {
-        var superRect = new Rectangle (0, 0, 100, 100);
-        var super = new View { Frame = superRect, Text = "super" };
-        var v1 = new View { X = 0, Y = 0, Width = 10, Height = 10 };
-
-        var v2 = new View { X = 10, Y = 10, Width = 10, Height = 10 };
-
-        super.Add (v1, v2);
-
-        super.LayoutSubviews ();
-        Assert.Equal (new (0, 0, 10, 10), v1.Frame);
-        Assert.Equal (new (10, 10, 10, 10), v2.Frame);
-        super.Dispose ();
-    }
-}

UnitTests/View/Layout/Dim.AutoTests.cs

@@ -4,12 +4,11 @@ using static Terminal.Gui.Dim;
 
 namespace Terminal.Gui.LayoutTests;
 
-[Trait("Category", "Layout")]
+[Trait ("Category", "Layout")]
 public partial class DimAutoTests (ITestOutputHelper output)
 {
     private readonly ITestOutputHelper _output = output;
 
-    [SetupFakeDriver]
     [Fact]
     public void Change_To_Non_Auto_Resets_ContentSize ()
     {
@@ -26,6 +25,7 @@ public partial class DimAutoTests (ITestOutputHelper output)
         // Change text to a longer string
         view.Text = "0123456789";
 
+        view.Layout (new (100, 100));
         Assert.Equal (new (0, 0, 10, 1), view.Frame);
         Assert.Equal (new (10, 1), view.GetContentSize ());
 
@@ -33,6 +33,7 @@ public partial class DimAutoTests (ITestOutputHelper output)
         view.Width = 5;
         view.Height = 1;
 
+        view.SetRelativeLayout (new (100, 100));
         Assert.Equal (new (5, 1), view.GetContentSize ());
     }
 
@@ -216,7 +217,7 @@ public partial class DimAutoTests (ITestOutputHelper output)
                              Style: DimAutoStyle.Auto
                             );
 
-        var c = new DimAuto(
+        var c = new DimAuto (
                              MaximumContentDim: 2,
                              MinimumContentDim: 1,
                              Style: DimAutoStyle.Auto
@@ -966,9 +967,9 @@ public partial class DimAutoTests (ITestOutputHelper output)
     [Fact]
     public void DimAutoStyle_Content_UsesLargestSubview_WhenContentSizeNotSet ()
     {
-        var view = new View ();
-        view.Add (new View { Frame = new (0, 0, 5, 5) }); // Smaller subview
-        view.Add (new View { Frame = new (0, 0, 10, 10) }); // Larger subview
+        var view = new View { Id = "view" };
+        view.Add (new View { Id = "smaller", Frame = new (0, 0, 5, 5) }); // Smaller subview
+        view.Add (new View { Id = "larger", Frame = new (0, 0, 10, 10) }); // Larger subview
 
         Dim dim = Auto (DimAutoStyle.Content);
 
@@ -990,6 +991,8 @@ public partial class DimAutoTests (ITestOutputHelper output)
     [Fact]
     public void DimAutoStyle_Content_Pos_AnchorEnd_Locates_Correctly ()
     {
+        Application.SetScreenSize (new Size (10, 10));
+
         DimAutoTestView view = new (Auto (DimAutoStyle.Content), Auto (DimAutoStyle.Content));
 
         View subView = new ()
@@ -999,24 +1002,23 @@ public partial class DimAutoTests (ITestOutputHelper output)
         };
         view.Add (subView);
 
-        view.SetRelativeLayout (new (10, 10));
+        view.Layout ();
         Assert.Equal (new (5, 1), view.Frame.Size);
         Assert.Equal (new (0, 0), view.Frame.Location);
 
         view.X = 0;
-
         view.Y = Pos.AnchorEnd (1);
-        view.SetRelativeLayout (new (10, 10));
+        view.Layout ();
         Assert.Equal (new (5, 1), view.Frame.Size);
         Assert.Equal (new (0, 9), view.Frame.Location);
 
         view.Y = Pos.AnchorEnd ();
-        view.SetRelativeLayout (new (10, 10));
+        view.Layout ();
         Assert.Equal (new (5, 1), view.Frame.Size);
         Assert.Equal (new (0, 9), view.Frame.Location);
 
         view.Y = Pos.AnchorEnd () - 1;
-        view.SetRelativeLayout (new (10, 10));
+        view.Layout ();
         Assert.Equal (new (5, 1), view.Frame.Size);
         Assert.Equal (new (0, 8), view.Frame.Location);
     }

UnitTests/View/Layout/LayoutTests.cs

@@ -6,6 +6,56 @@ public class LayoutTests (ITestOutputHelper output)
 {
     private readonly ITestOutputHelper _output = output;
 
+
+    [Fact]
+    [AutoInitShutdown]
+    public void Screen_Size_Change_Causes_Layout ()
+    {
+        Application.Top = new ();
+
+        var view = new View
+        {
+            X = 3,
+            Y = 2,
+            Width = 10,
+            Height = 1,
+            Text = "0123456789"
+        };
+        Application.Top.Add (view);
+
+        var rs = Application.Begin (Application.Top);
+
+        Assert.Equal (new (0, 0, 80, 25), new Rectangle (0, 0, View.Driver.Cols, View.Driver.Rows));
+        Assert.Equal (new (0, 0, View.Driver.Cols, View.Driver.Rows), Application.Top.Frame);
+        Assert.Equal (new (0, 0, 80, 25), Application.Top.Frame);
+
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 10);
+        Assert.Equal (new (0, 0, View.Driver.Cols, View.Driver.Rows), Application.Top.Frame);
+
+        Assert.Equal (new (0, 0, 20, 10), Application.Top.Frame);
+
+        Application.End (rs);
+
+    }
+
+    [Fact]
+    [TestRespondersDisposed]
+    public void LayoutSubviews ()
+    {
+        var superRect = new Rectangle (0, 0, 100, 100);
+        var super = new View { Frame = superRect, Text = "super" };
+        var v1 = new View { X = 0, Y = 0, Width = 10, Height = 10 };
+
+        var v2 = new View { X = 10, Y = 10, Width = 10, Height = 10 };
+
+        super.Add (v1, v2);
+
+        super.LayoutSubviews ();
+        Assert.Equal (new (0, 0, 10, 10), v1.Frame);
+        Assert.Equal (new (10, 10, 10, 10), v2.Frame);
+        super.Dispose ();
+    }
+
     [Fact]
     public void LayoutSubviews_No_SuperView ()
     {
@@ -35,7 +85,7 @@ public class LayoutTests (ITestOutputHelper output)
     }
 
     [Fact]
-    public void Add_Does_Not_Call_LayoutSubviews ()
+    public void Add_Does_Not_Call_Layout ()
     {
         var superView = new View { Id = "superView" };
         var view = new View { Id = "view" };
@@ -49,10 +99,7 @@ public class LayoutTests (ITestOutputHelper output)
         Assert.False (layoutStartedRaised);
         Assert.False (layoutCompleteRaised);
 
-        superView.Remove(view);
-
-        superView.BeginInit();
-        superView.EndInit ();
+        superView.Remove (view);
 
         superView.Add (view);
 
@@ -61,20 +108,6 @@ public class LayoutTests (ITestOutputHelper output)
 
     }
 
-    [Fact]
-    public void BeginEndInit_Do_Not_Call_LayoutSubviews ()
-    {
-        var superView = new View { Id = "superView" };
-        bool layoutStartedRaised = false;
-        bool layoutCompleteRaised = false;
-        superView.LayoutStarted += (sender, e) => layoutStartedRaised = true;
-        superView.LayoutComplete += (sender, e) => layoutCompleteRaised = true;
-        superView.BeginInit ();
-        superView.EndInit ();
-        Assert.False (layoutStartedRaised);
-        Assert.False (layoutCompleteRaised);
-    }
-
     [Fact]
     public void LayoutSubViews_Raises_LayoutStarted_LayoutComplete ()
     {
@@ -203,38 +236,376 @@ public class LayoutTests (ITestOutputHelper output)
     {
         var superView = new View ();
         var view = new View ();
+
+        var layoutStartedCount = 0;
+        var layoutCompleteCount = 0;
+
+        var borderLayoutStartedCount = 0;
+        var borderLayoutCompleteCount = 0;
+
+        view.LayoutStarted += (sender, e) => layoutStartedCount++;
+        view.LayoutComplete += (sender, e) => layoutCompleteCount++;
+
+        view.Border.LayoutStarted += (sender, e) => borderLayoutStartedCount++;
+        view.Border.LayoutComplete += (sender, e) => borderLayoutCompleteCount++;
+
+
         superView.Add (view);
+        Assert.Equal (0, borderLayoutStartedCount);
+        Assert.Equal (0, borderLayoutCompleteCount);
+        Assert.Equal (0, layoutStartedCount);
+        Assert.Equal (0, layoutCompleteCount);
+
         superView.BeginInit ();
+        Assert.Equal (0, borderLayoutStartedCount);
+        Assert.Equal (0, borderLayoutCompleteCount);
+        Assert.Equal (0, layoutStartedCount);
+        Assert.Equal (0, layoutCompleteCount);
+
         superView.EndInit ();
-
-        var layoutStarted = false;
-        var layoutComplete = false;
-
-        var borderLayoutStarted = false;
-        var borderLayoutComplete = false;
-
-        view.LayoutStarted += (sender, e) => layoutStarted = true;
-        view.LayoutComplete += (sender, e) => layoutComplete = true;
-
-        view.Border.LayoutStarted += (sender, e) =>
-                                     {
-                                         Assert.True (layoutStarted);
-                                         borderLayoutStarted = true;
-                                     };
-        view.Border.LayoutComplete += (sender, e) =>
-                                      {
-                                          Assert.True (layoutStarted);
-                                          Assert.False (layoutComplete);
-                                          borderLayoutComplete = true;
-                                      };
+        Assert.Equal (1, borderLayoutStartedCount);
+        Assert.Equal (1, borderLayoutCompleteCount);
+        Assert.Equal (1, layoutStartedCount);
+        Assert.Equal (1, layoutCompleteCount);
 
         superView.LayoutSubviews ();
+        Assert.Equal (1, borderLayoutStartedCount);
+        Assert.Equal (1, borderLayoutCompleteCount);
+        Assert.Equal (1, layoutStartedCount);
+        Assert.Equal (1, layoutCompleteCount);
 
-        Assert.True (borderLayoutStarted);
-        Assert.True (borderLayoutComplete);
+        superView.SetLayoutNeeded ();
+        superView.LayoutSubviews ();
+        Assert.Equal (2, borderLayoutStartedCount);
+        Assert.Equal (2, borderLayoutCompleteCount);
+        Assert.Equal (2, layoutStartedCount);
+        Assert.Equal (2, layoutCompleteCount);
 
-        Assert.True (layoutStarted);
-        Assert.True (layoutComplete);
         superView.Dispose ();
     }
+
+    [Fact]
+    public void LayoutSubviews__Honors_IsLayoutNeeded ()
+    {
+        var superView = new View ();
+        var view = new View ();
+
+        var layoutStartedCount = 0;
+        var layoutCompleteCount = 0;
+
+        var borderLayoutStartedCount = 0;
+        var borderLayoutCompleteCount = 0;
+
+        view.LayoutStarted += (sender, e) => layoutStartedCount++;
+        view.LayoutComplete += (sender, e) => layoutCompleteCount++;
+
+        view.Border.LayoutStarted += (sender, e) => borderLayoutStartedCount++;
+        view.Border.LayoutComplete += (sender, e) => borderLayoutCompleteCount++;
+
+
+        superView.Add (view);
+
+        superView.LayoutSubviews ();
+        Assert.Equal (1, borderLayoutStartedCount);
+        Assert.Equal (1, borderLayoutCompleteCount);
+        Assert.Equal (1, layoutStartedCount);
+        Assert.Equal (1, layoutCompleteCount);
+
+        superView.LayoutSubviews ();
+        Assert.Equal (1, borderLayoutStartedCount);
+        Assert.Equal (1, borderLayoutCompleteCount);
+        Assert.Equal (1, layoutStartedCount);
+        Assert.Equal (1, layoutCompleteCount);
+
+        superView.SetLayoutNeeded ();
+        superView.LayoutSubviews ();
+        Assert.Equal (2, borderLayoutStartedCount);
+        Assert.Equal (2, borderLayoutCompleteCount);
+        Assert.Equal (2, layoutStartedCount);
+        Assert.Equal (2, layoutCompleteCount);
+
+        superView.Dispose ();
+    }
+
+    [Fact]
+    public void Set_X_Does_Not_Change_Frame_Until_Layout ()
+    {
+        var v = new View ();
+        Assert.Equal (0, v.Frame.X);
+
+        v.Layout ();
+        Assert.Equal (0, v.Frame.X);
+
+        v.X = 1;
+        Assert.Equal (0, v.Frame.X);
+
+        v.Layout ();
+        Assert.Equal (1, v.Frame.X);
+
+        v.X = 2;
+        Assert.Equal (1, v.Frame.X);
+
+        v.Layout ();
+        Assert.Equal (2, v.Frame.X);
+    }
+
+
+    [Fact]
+    public void Set_Y_Does_Not_Change_Frame_Until_Layout ()
+    {
+        var v = new View ();
+        Assert.Equal (0, v.Frame.Y);
+
+        v.Layout ();
+        Assert.Equal (0, v.Frame.Y);
+
+        v.Y = 1;
+        Assert.Equal (0, v.Frame.Y);
+
+        v.Layout ();
+        Assert.Equal (1, v.Frame.Y);
+
+        v.Y = 2;
+        Assert.Equal (1, v.Frame.Y);
+
+        v.Layout ();
+        Assert.Equal (2, v.Frame.Y);
+    }
+
+
+    [Fact]
+    public void Set_Width_Does_Not_Change_Frame_Until_Layout ()
+    {
+        var v = new View ();
+        Assert.Equal (0, v.Frame.Width);
+
+        v.Layout ();
+        Assert.Equal (0, v.Frame.Width);
+
+        v.Width = 1;
+        Assert.Equal (0, v.Frame.Width);
+
+        v.Layout ();
+        Assert.Equal (1, v.Frame.Width);
+
+        v.Width = 2;
+        Assert.Equal (1, v.Frame.Width);
+
+        v.Layout ();
+        Assert.Equal (2, v.Frame.Width);
+    }
+
+
+    [Fact]
+    public void Set_Height_Does_Not_Change_Frame_Until_Layout ()
+    {
+        var v = new View ();
+        Assert.Equal (0, v.Frame.Height);
+
+        v.Layout ();
+        Assert.Equal (0, v.Frame.Height);
+
+        v.Height = 1;
+        Assert.Equal (0, v.Frame.Height);
+
+        v.Layout ();
+        Assert.Equal (1, v.Frame.Height);
+
+        v.Height = 2;
+        Assert.Equal (1, v.Frame.Height);
+
+        v.Layout ();
+        Assert.Equal (2, v.Frame.Height);
+    }
+
+    [Fact]
+    [TestRespondersDisposed]
+    public void Change_Height_or_Width_MakesComputed ()
+    {
+        var v = new View { Frame = Rectangle.Empty };
+        v.Height = Dim.Fill ();
+        v.Width = Dim.Fill ();
+        v.Dispose ();
+    }
+
+    [Fact]
+    [TestRespondersDisposed]
+    public void Change_X_or_Y_Absolute ()
+    {
+        var frame = new Rectangle (1, 2, 3, 4);
+        var newFrame = new Rectangle (10, 20, 3, 4);
+
+        var v = new View { Frame = frame };
+        v.X = newFrame.X;
+        v.Y = newFrame.Y;
+        v.Layout ();
+        Assert.Equal (newFrame, v.Frame);
+
+        Assert.Equal (
+                      new (0, 0, newFrame.Width, newFrame.Height),
+                      v.Viewport
+                     ); // With Absolute Viewport *is* deterministic before Layout
+        Assert.Equal ($"Absolute({newFrame.X})", v.X.ToString ());
+        Assert.Equal ($"Absolute({newFrame.Y})", v.Y.ToString ());
+        Assert.Equal (Dim.Absolute (3), v.Width);
+        Assert.Equal (Dim.Absolute (4), v.Height);
+        v.Dispose ();
+    }
+
+    [Fact]
+    [TestRespondersDisposed]
+    public void Change_X_or_Y_MakesComputed ()
+    {
+        var v = new View { Frame = Rectangle.Empty };
+        v.X = Pos.Center ();
+        v.Y = Pos.Center ();
+        v.Dispose ();
+    }
+
+    [Fact]
+    [TestRespondersDisposed]
+    public void Change_X_Y_Height_Width_Absolute ()
+    {
+        var v = new View { Frame = Rectangle.Empty };
+        v.X = 1;
+        v.Y = 2;
+        v.Height = 3;
+        v.Width = 4;
+        v.Dispose ();
+
+        v = new () { Frame = Rectangle.Empty };
+        v.X = Pos.Center ();
+        v.Y = Pos.Center ();
+        v.Width = Dim.Fill ();
+        v.Height = Dim.Fill ();
+        v.Dispose ();
+
+        v = new () { Frame = Rectangle.Empty };
+        v.X = Pos.Center ();
+        v.Y = Pos.Center ();
+        v.Width = Dim.Fill ();
+        v.Height = Dim.Fill ();
+
+        v.X = 1;
+        v.Dispose ();
+
+        v = new () { Frame = Rectangle.Empty };
+        v.X = Pos.Center ();
+        v.Y = Pos.Center ();
+        v.Width = Dim.Fill ();
+        v.Height = Dim.Fill ();
+
+        v.Y = 2;
+        v.Dispose ();
+
+        v = new () { Frame = Rectangle.Empty };
+        v.X = Pos.Center ();
+        v.Y = Pos.Center ();
+        v.Width = Dim.Fill ();
+        v.Height = Dim.Fill ();
+
+        v.Width = 3;
+        v.Dispose ();
+
+        v = new () { Frame = Rectangle.Empty };
+        v.X = Pos.Center ();
+        v.Y = Pos.Center ();
+        v.Width = Dim.Fill ();
+        v.Height = Dim.Fill ();
+
+        v.Height = 3;
+        v.Dispose ();
+
+        v = new () { Frame = Rectangle.Empty };
+        v.X = Pos.Center ();
+        v.Y = Pos.Center ();
+        v.Width = Dim.Fill ();
+        v.Height = Dim.Fill ();
+
+        v.X = 1;
+        v.Y = 2;
+        v.Height = 3;
+        v.Width = 4;
+        v.Dispose ();
+    }
+
+    [Fact]
+    public void Constructor ()
+    {
+        var v = new View ();
+        v.Dispose ();
+
+        var frame = Rectangle.Empty;
+        v = new () { Frame = frame };
+        v.Layout ();
+        Assert.Equal (frame, v.Frame);
+
+        Assert.Equal (
+                      new (0, 0, frame.Width, frame.Height),
+                      v.Viewport
+                     ); // With Absolute Viewport *is* deterministic before Layout
+        Assert.Equal (Pos.Absolute (0), v.X);
+        Assert.Equal (Pos.Absolute (0), v.Y);
+        Assert.Equal (Dim.Absolute (0), v.Width);
+        Assert.Equal (Dim.Absolute (0), v.Height);
+        v.Dispose ();
+
+        frame = new (1, 2, 3, 4);
+        v = new () { Frame = frame };
+        v.Layout ();
+        Assert.Equal (frame, v.Frame);
+        Assert.Equal (
+                      new (0, 0, frame.Width, frame.Height),
+                      v.Viewport
+                     ); // With Absolute Viewport *is* deterministic before Layout
+        Assert.Equal (Pos.Absolute (1), v.X);
+        Assert.Equal (Pos.Absolute (2), v.Y);
+        Assert.Equal (Dim.Absolute (3), v.Width);
+        Assert.Equal (Dim.Absolute (4), v.Height);
+        v.Dispose ();
+
+        v = new () { Frame = frame, Text = "v" };
+        v.Layout ();
+        Assert.Equal (frame, v.Frame);
+        Assert.Equal (
+                      new (0, 0, frame.Width, frame.Height),
+                      v.Viewport
+                     ); // With Absolute Viewport *is* deterministic before Layout
+        Assert.Equal (Pos.Absolute (1), v.X);
+        Assert.Equal (Pos.Absolute (2), v.Y);
+        Assert.Equal (Dim.Absolute (3), v.Width);
+        Assert.Equal (Dim.Absolute (4), v.Height);
+        v.Dispose ();
+
+        v = new () { X = frame.X, Y = frame.Y, Text = "v" };
+        v.Layout ();
+        Assert.Equal (new (frame.X, frame.Y, 0, 0), v.Frame);
+        Assert.Equal (new (0, 0, 0, 0), v.Viewport); // With Absolute Viewport *is* deterministic before Layout
+        Assert.Equal (Pos.Absolute (1), v.X);
+        Assert.Equal (Pos.Absolute (2), v.Y);
+        Assert.Equal (Dim.Absolute (0), v.Width);
+        Assert.Equal (Dim.Absolute (0), v.Height);
+        v.Dispose ();
+
+        v = new ();
+        v.Layout ();
+        Assert.Equal (new (0, 0, 0, 0), v.Frame);
+        Assert.Equal (new (0, 0, 0, 0), v.Viewport); // With Absolute Viewport *is* deterministic before Layout
+        Assert.Equal (Pos.Absolute (0), v.X);
+        Assert.Equal (Pos.Absolute (0), v.Y);
+        Assert.Equal (Dim.Absolute (0), v.Width);
+        Assert.Equal (Dim.Absolute (0), v.Height);
+        v.Dispose ();
+
+        v = new () { X = frame.X, Y = frame.Y, Width = frame.Width, Height = frame.Height };
+        v.Layout ();
+        Assert.Equal (new (frame.X, frame.Y, 3, 4), v.Frame);
+        Assert.Equal (new (0, 0, 3, 4), v.Viewport); // With Absolute Viewport *is* deterministic before Layout
+        Assert.Equal (Pos.Absolute (1), v.X);
+        Assert.Equal (Pos.Absolute (2), v.Y);
+        Assert.Equal (Dim.Absolute (3), v.Width);
+        Assert.Equal (Dim.Absolute (4), v.Height);
+        v.Dispose ();
+    }
+
 }

UnitTests/View/Layout/Pos.CenterTests.cs

@@ -94,7 +94,7 @@ public class PosCenterTests (ITestOutputHelper output)
         var firstIteration = false;
 
         ((FakeDriver)Application.Driver!).SetBufferSize (20, height);
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, firstIteration);
         var expected = string.Empty;
 
         switch (height)
@@ -241,7 +241,7 @@ public class PosCenterTests (ITestOutputHelper output)
         var firstIteration = false;
 
         ((FakeDriver)Application.Driver!).SetBufferSize (width, 7);
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, firstIteration);
         var expected = string.Empty;
 
         switch (width)

UnitTests/View/Layout/ToScreenTests.cs

@@ -960,7 +960,7 @@ public class ToScreenTests (ITestOutputHelper output)
         };
         Application.Top.Add (view);
 
-        Application.Begin (Application.Top);
+        var rs = Application.Begin (Application.Top);
 
         Assert.Equal (new (0, 0, 80, 25), new Rectangle (0, 0, View.Driver.Cols, View.Driver.Rows));
         Assert.Equal (new (0, 0, View.Driver.Cols, View.Driver.Rows), Application.Top.Frame);
@@ -970,6 +970,7 @@ public class ToScreenTests (ITestOutputHelper output)
         Assert.Equal (new (0, 0, View.Driver.Cols, View.Driver.Rows), Application.Top.Frame);
         Assert.Equal (new (0, 0, 20, 10), Application.Top.Frame);
 
+
         _ = TestHelpers.AssertDriverContentsWithFrameAre (
                                                           @"
 ┌──────────────────┐

UnitTests/View/Mouse/MouseTests.cs

@@ -103,12 +103,15 @@ public class MouseTests (ITestOutputHelper output) : TestsAllViews
 
         var top = new Toplevel ();
         top.Add (testView);
-        Application.Begin (top);
+
+        var rs = Application.Begin (top);
+        Assert.Equal (4, testView.Frame.X);
 
         Assert.Equal (new Point (4, 4), testView.Frame.Location);
         Application.RaiseMouseEvent (new () { ScreenPosition = new (xy, xy), Flags = MouseFlags.Button1Pressed });
 
         Application.RaiseMouseEvent (new () { ScreenPosition = new (xy + 1, xy + 1), Flags = MouseFlags.Button1Pressed | MouseFlags.ReportMousePosition });
+        Application.RunIteration(ref rs, false);
 
         Assert.Equal (expectedMoved, new Point (5, 5) == testView.Frame.Location);
         top.Dispose ();

UnitTests/View/ViewTests.cs

@@ -1025,7 +1025,7 @@ At 0,0
         view.Visible = false;
 
         var firstIteration = false;
-        Application.RunIteration (ref rs, ref firstIteration);
+        Application.RunIteration (ref rs, firstIteration);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"