Fixes #3951. Adds View dependency to DimFunc and PosFunc

Examples/UICatalog/Scenarios/CharacterMap/CharacterMap.cs

@@ -39,7 +39,6 @@ public override void Main ()
         {
             X = 0,
             Y = 1,
-            Width = Dim.Fill (Dim.Func (() => _categoryList!.Frame.Width)),
             Height = Dim.Fill (),
            // SchemeName = "Base"
 
@@ -172,6 +171,8 @@ public override void Main ()
         };
         top.Add (menu);
 
+        _charMap.Width = Dim.Fill (Dim.FuncWithView (v => v!.Frame.Width, _categoryList));
+
         _charMap.SelectedCodePoint = 0;
         _charMap.SetFocus ();
 

Terminal.Gui/App/Application.Run.cs

@@ -189,7 +189,7 @@ public static RunState Begin (Toplevel toplevel)
         if (!toplevel.IsInitialized)
         {
             toplevel.BeginInit ();
-            toplevel.EndInit (); // Calls Layout
+            toplevel.EndInit (); // Calls SetNeedsLayout
         }
 
         // Call ConfigurationManager Apply here to ensure all subscribers to ConfigurationManager.Applied
@@ -205,16 +205,15 @@ public static RunState Begin (Toplevel toplevel)
 
         toplevel.OnLoaded ();
 
+        LayoutAndDraw (true);
+
         if (PositionCursor ())
         {
             Driver?.UpdateCursor ();
         }
 
         NotifyNewRunState?.Invoke (toplevel, new (rs));
 
-        // Force an Idle event so that an Iteration (and Refresh) happen.
-        Invoke (() => { });
-
         return rs;
     }
 

Terminal.Gui/ViewBase/Layout/Dim.cs

@@ -148,6 +148,16 @@ public abstract record Dim : IEqualityOperators<Dim, Dim, bool>
     /// <returns>The <see cref="Dim"/> returned from the function.</returns>
     public static Dim Func (Func<int> function) { return new DimFunc (function); }
 
+    /// <summary>
+    ///     Creates a function <see cref="Dim"/> object that computes the dimension based on the passed view and by executing
+    ///     the provided function.
+    ///     The function will be called every time the dimension is needed.
+    /// </summary>
+    /// <param name="function">The function to be executed.</param>
+    /// <param name="view">The view where the data will be retrieved.</param>
+    /// <returns>The <see cref="Dim"/> returned from the function based on the passed view.</returns>
+    public static Dim FuncWithView (Func<View, int> function, View? view) { return new DimFuncWithView (function, view); }
+
     /// <summary>Creates a <see cref="Dim"/> object that tracks the Height of the specified <see cref="View"/>.</summary>
     /// <returns>The height <see cref="Dim"/> of the other <see cref="View"/>.</returns>
     /// <param name="view">The view that will be tracked.</param>

Terminal.Gui/ViewBase/Layout/DimFuncWithView.cs

@@ -0,0 +1,35 @@
+#nullable enable
+namespace Terminal.Gui.ViewBase;
+
+/// <summary>
+///     Represents a function <see cref="Dim"/> object that computes the dimension based on the passed view and by
+///     executing the provided function.
+/// </summary>
+/// <remarks>
+///     This is a low-level API that is typically used internally by the layout system. Use the various static
+///     methods on the <see cref="Dim"/> class to create <see cref="Dim"/> objects instead.
+/// </remarks>
+/// <param name="Fn">The function that computes the dimension. If this function throws <see cref="LayoutException"/>... </param>
+/// <param name="View">The <see cref="Dim"/> returned from the function based on the passed view.</param>
+public record DimFuncWithView (Func<View, int> Fn, View? View) : Dim
+{
+    /// <summary>
+    ///     Gets the function that computes the dimension.
+    /// </summary>
+    public Func<View, int> Fn { get; } = Fn;
+
+    /// <summary>
+    ///     Gets the passed view that the dimension is based on.
+    /// </summary>
+    public View View { get; } = View ?? throw new ArgumentNullException (nameof (View), @"View cannot be null");
+
+    /// <inheritdoc/>
+    public override string ToString () { return $"DimFuncWithView({Fn (View)})"; }
+
+    internal override int GetAnchor (int size)
+    {
+        View?.Layout ();
+
+        return Fn (View!);
+    }
+}

Terminal.Gui/ViewBase/View.cs

@@ -245,13 +245,6 @@ public virtual void EndInit ()
             }
         }
 
-        // Force a layout each time a View is initialized
-        // See: https://github.com/gui-cs/Terminal.Gui/issues/3951
-        // See: https://github.com/gui-cs/Terminal.Gui/issues/4204
-        Layout (); // the EventLog in AllViewsTester fails to layout correctly if this is not here (convoluted Dim.Fill(Func)).
-
-        // Complex layout scenarios (e.g. DimAuto and PosAlign) may require multiple layouts to be performed.
-        // Thus, we call SetNeedsLayout() to ensure that the layout is performed at least once.
         SetNeedsLayout ();
 
         Initialized?.Invoke (this, EventArgs.Empty);

Tests/UnitTests/View/Adornment/ShadowStyleTests.cs

@@ -152,6 +152,7 @@ public void ShadowStyle_Button1Pressed_Causes_Movement (ShadowStyle style, int e
         superView.Add (view);
         superView.BeginInit ();
         superView.EndInit ();
+        superView.Layout ();
 
         Thickness origThickness = view.Margin!.Thickness;
         view.NewMouseEvent (new () { Flags = MouseFlags.Button1Pressed, Position = new (0, 0) });

Tests/UnitTests/View/Draw/ClearViewportTests.cs

@@ -113,8 +113,7 @@ public void Clear_ClearsEntireViewport ()
         superView.Add (view);
         superView.BeginInit ();
         superView.EndInit ();
-        superView.LayoutSubViews ();
-
+        superView.Layout ();
         superView.Draw ();
 
         DriverAssert.AssertDriverContentsWithFrameAre (
@@ -163,7 +162,7 @@ public void Clear_WithClearVisibleContentOnly_ClearsVisibleContentOnly ()
         superView.Add (view);
         superView.BeginInit ();
         superView.EndInit ();
-        superView.LayoutSubViews ();
+        superView.Layout ();
 
         superView.Draw ();
 

Tests/UnitTests/View/Draw/ClipTests.cs

@@ -79,7 +79,7 @@ public void FillRect_Fills_HonorsClip (int x, int y, int width, int height)
         superView.Add (view);
         superView.BeginInit ();
         superView.EndInit ();
-        superView.LayoutSubViews ();
+        superView.Layout ();
 
         superView.Draw ();
 
@@ -258,6 +258,7 @@ public void SetClip_ClipVisibleContentOnly_VisibleContentIsClipped ()
         view.Border!.Thickness = new (1);
         view.BeginInit ();
         view.EndInit ();
+        view.Layout ();
         Assert.Equal (view.Frame, View.GetClip ()!.GetBounds ());
 
         // Act
@@ -291,6 +292,7 @@ public void SetClip_Default_ClipsToViewport ()
         view.Border!.Thickness = new (1);
         view.BeginInit ();
         view.EndInit ();
+        view.Layout ();
         Assert.Equal (view.Frame, View.GetClip ()!.GetBounds ());
         view.Viewport = view.Viewport with { X = 1, Y = 1 };
 

Tests/UnitTests/View/Layout/GetViewsUnderLocationTests.cs

@@ -327,6 +327,7 @@ public void Returns_Correct_If_Start_Has_Adornment_WithSubView (int testX, int t
         Application.Top.Padding.Add (subview);
         Application.Top.BeginInit ();
         Application.Top.EndInit ();
+        Application.Top.LayoutSubViews ();
 
         View? found = View.GetViewsUnderLocation (new (testX, testY), ViewportSettingsFlags.TransparentMouse).LastOrDefault ();
 
@@ -489,6 +490,7 @@ public void Returns_Correct_If_SubView_Has_Adornment_WithSubView (int testX, int
         Application.Top.Add (subview);
         Application.Top.BeginInit ();
         Application.Top.EndInit ();
+        Application.Top.LayoutSubViews ();
 
         View? found = View.GetViewsUnderLocation (new (testX, testY), ViewportSettingsFlags.TransparentMouse).LastOrDefault ();
 
@@ -540,6 +542,7 @@ public void Returns_Correct_If_SubView_Is_Scrolled_And_Has_Adornment_WithSubView
         Application.Top.Add (subview);
         Application.Top.BeginInit ();
         Application.Top.EndInit ();
+        Application.Top.LayoutSubViews ();
 
         View? found = View.GetViewsUnderLocation (new (testX, testY), ViewportSettingsFlags.TransparentMouse).LastOrDefault ();
 

Tests/UnitTests/View/Mouse/MouseTests.cs

@@ -191,6 +191,7 @@ public void WantContinuousButtonPressed_True_And_WantMousePositionReports_True_B
 
         // When mouse is held down
         me.Flags = pressed;
+        view.Layout ();
         view.NewMouseEvent (me);
         Assert.Equal (0, clickedCount);
         me.Handled = false;

Tests/UnitTests/View/TextTests.cs

@@ -1024,6 +1024,7 @@ public void Narrow_Wide_Runes ()
         top.Add (frame);
         top.BeginInit ();
         top.EndInit ();
+        top.Layout ();
 
         Assert.Equal (new (0, 0, 20, 1), horizontalView.Frame);
         Assert.Equal (new (0, 3, 1, 20), verticalView.Frame);
@@ -1127,6 +1128,7 @@ public void SetText_RendersCorrectly ()
         view = new Label { Text = text };
         view.BeginInit ();
         view.EndInit ();
+        view.Layout ();
         view.Draw ();
 
         DriverAssert.AssertDriverContentsWithFrameAre (text, output);

Tests/UnitTests/View/ViewTests.cs

@@ -291,6 +291,7 @@ public void New_Initializes ()
 
         r.BeginInit ();
         r.EndInit ();
+        r.Layout ();
         Assert.False (r.CanFocus);
         Assert.False (r.HasFocus);
         Assert.Equal (new (0, 0, 1, 13), r.Viewport);

Tests/UnitTests/Views/ButtonTests.cs

@@ -232,6 +232,7 @@ public void Constructors_Defaults ()
         Assert.True (btn.CanFocus);
 
         Application.Driver?.ClearContents ();
+        btn.Layout ();
         btn.Draw ();
 
         expected = @$"

Tests/UnitTests/Views/ColorPicker16Tests.cs

@@ -14,7 +14,7 @@ public void Constructors ()
 
         colorPicker.BeginInit ();
         colorPicker.EndInit ();
-        colorPicker.LayoutSubViews ();
+        colorPicker.Layout ();
         Assert.Equal (new (0, 0, 32, 4), colorPicker.Frame);
     }
 

Tests/UnitTests/Views/ColorPickerTests.cs

@@ -675,7 +675,7 @@ public void ColorPicker_SwitchingColorModels_ResetsBars ()
         // Switch to HSV
         cp.Style.ColorModel = ColorModel.HSV;
         cp.ApplyStyleChanges ();
-
+        cp.Layout ();
         cp.Draw ();
 
         ColorBar h = GetColorBar (cp, ColorPickerPart.Bar1);

Tests/UnitTests/Views/LabelTests.cs

@@ -1053,7 +1053,7 @@ public void Label_Height_Zero_Stays_Zero ()
         win.Add (label);
         win.BeginInit ();
         win.EndInit ();
-        win.LayoutSubViews ();
+        win.Layout ();
         win.Draw ();
 
         Assert.Equal (5, text.Length);

Tests/UnitTests/Views/Menuv1/MenuBarv1Tests.cs

@@ -2130,6 +2130,7 @@ public void MenuBar_Position_And_Size_With_HotKeys_Is_The_Same_As_Without_HotKey
         Assert.True (menu.NewKeyDownEvent (menu.Key));
         Assert.True (menu.IsMenuOpen);
         View.SetClipToScreen ();
+        top.Layout ();
         top.Draw ();
         DriverAssert.AssertDriverContentsAre (expectedMenu.ExpectedSubMenuOpen (0), output);
 

Tests/UnitTests/Views/ProgressBarTests.cs

@@ -12,7 +12,7 @@ public void Default_Constructor ()
         var pb = new ProgressBar ();
         pb.BeginInit ();
         pb.EndInit ();
-
+        pb.Layout ();
         Assert.False (pb.CanFocus);
         Assert.Equal (0, pb.Fraction);
 
@@ -32,7 +32,7 @@ public void Fraction_Redraw ()
 
         pb.BeginInit ();
         pb.EndInit ();
-        pb.LayoutSubViews ();
+        pb.Layout ();
 
         for (var i = 0; i <= pb.Frame.Width; i++)
         {
@@ -174,7 +174,7 @@ public void Pulse_Redraw_BidirectionalMarquee_False ()
 
         pb.BeginInit ();
         pb.EndInit ();
-        pb.LayoutSubViews ();
+        pb.Layout ();
 
         for (var i = 0; i < 38; i++)
         {
@@ -879,7 +879,7 @@ public void Pulse_Redraw_BidirectionalMarquee_True_Default ()
 
         pb.BeginInit ();
         pb.EndInit ();
-        pb.LayoutSubViews ();
+        pb.Layout ();
 
         for (var i = 0; i < 38; i++)
         {

Tests/UnitTests/Views/SliderTests.cs

@@ -514,6 +514,7 @@ private void DimAuto_Both_Respects_SuperView_ContentSize ()
         view.Add (slider);
         view.BeginInit ();
         view.EndInit ();
+        view.Layout ();
 
         Size expectedSize = slider.Frame.Size;
 
@@ -547,6 +548,7 @@ private void DimAuto_Width_Respects_SuperView_ContentSize ()
         view.Add (slider);
         view.BeginInit ();
         view.EndInit ();
+        view.Layout ();
 
         Size expectedSize = slider.Frame.Size;
 
@@ -580,6 +582,7 @@ private void DimAuto_Height_Respects_SuperView_ContentSize ()
         view.Add (slider);
         view.BeginInit ();
         view.EndInit ();
+        view.Layout ();
 
         Size expectedSize = slider.Frame.Size;
 

Tests/UnitTests/Views/TextFieldTests.cs

@@ -1673,6 +1673,7 @@ public void Draw_Esc_Rune ()
         var tf = new TextField { Width = 5, Text = "\u001b" };
         tf.BeginInit ();
         tf.EndInit ();
+        tf.Layout ();
         tf.Draw ();
 
         DriverAssert.AssertDriverContentsWithFrameAre ("\u241b", output);

Tests/UnitTests/Views/TileViewTests.cs

@@ -819,6 +819,10 @@ public void TestDisposal_NoEarlyDisposalsOfUsersViews_DuringRebuildForTileCount
                              Assert.Equal (1, myReusableView.DisposalCount);
                          }
                         );
+
+        Assert.NotNull (Application.Top);
+        Application.Top.Dispose ();
+        Application.Shutdown ();
     }
 
     [Theory]
@@ -848,6 +852,10 @@ public void TestDisposal_NoEarlyDisposalsOfUsersViews_DuringRemoveTile (int idx)
                              Assert.True (myReusableView.DisposalCount >= 1);
                          }
                         );
+
+        Assert.NotNull (Application.Top);
+        Application.Top.Dispose ();
+        Application.Shutdown ();
     }
 
     [Fact]