Fixes #2705. ListView does not render correctly before focus. (#2707)

Terminal.Gui/Core/View.cs

@@ -446,11 +446,10 @@ namespace Terminal.Gui {
 		public virtual Rect Frame {
 			get => frame;
 			set {
-				var rect = GetMaxNeedDisplay (frame, value);
-				frame = new Rect (value.X, value.Y, Math.Max (value.Width, 0), Math.Max (value.Height, 0));
+				frame = value;
 				TextFormatter.Size = GetBoundsTextFormatterSize ();
 				SetNeedsLayout ();
-				SetNeedsDisplay (rect);
+				SetNeedsDisplay ();
 			}
 		}
 
@@ -823,21 +822,7 @@ namespace Terminal.Gui {
 			}
 			TextFormatter.Size = GetBoundsTextFormatterSize ();
 			SetNeedsLayout ();
-			SetNeedsDisplay (GetMaxNeedDisplay (oldFrame, frame));
-		}
-
-		Rect GetMaxNeedDisplay (Rect oldFrame, Rect newFrame)
-		{
-			var rect = new Rect () {
-				X = Math.Min (oldFrame.X, newFrame.X),
-				Y = Math.Min (oldFrame.Y, newFrame.Y),
-				Width = Math.Max (oldFrame.Width, newFrame.Width),
-				Height = Math.Max (oldFrame.Height, newFrame.Height)
-			};
-			rect.Width += Math.Max (oldFrame.X - newFrame.X, 0);
-			rect.Height += Math.Max (oldFrame.Y - newFrame.Y, 0);
-
-			return rect;
+			SetNeedsDisplay ();
 		}
 
 		void TextFormatter_HotKeyChanged (Key obj)

UnitTests/Views/ViewTests.cs

@@ -1,6 +1,5 @@
 using NStack;
 using System;
-using System.Collections.Generic;
 using Terminal.Gui.Graphs;
 using Xunit;
 using Xunit.Abstractions;
@@ -3991,6 +3990,11 @@ This is a tes
 				CanFocus = true;
 			}
 
+			public DerivedView (Rect rect) : base (rect)
+			{
+				CanFocus = true;
+			}
+
 			public bool IsKeyDown { get; set; }
 			public bool IsKeyPress { get; set; }
 			public bool IsKeyUp { get; set; }
@@ -4014,22 +4018,9 @@ This is a tes
 				return true;
 			}
 
-			public void CorrectRedraw (Rect bounds)
+			public override void Redraw (Rect bounds)
 			{
-				// Clear the old and new frame area
-				Clear (NeedDisplay);
-				DrawText ();
-			}
-
-			public void IncorrectRedraw (Rect bounds)
-			{
-				// Clear only the new frame area
 				Clear ();
-				DrawText ();
-			}
-
-			private void DrawText ()
-			{
 				var idx = 0;
 				for (int r = 0; r < Frame.Height; r++) {
 					for (int c = 0; c < Frame.Width; c++) {
@@ -4218,38 +4209,35 @@ cccccccccccccccccccc", output);
 		}
 
 		[Fact, AutoInitShutdown]
-		public void Correct_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Up_Left_Using_Frame ()
+		public void Correct_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Up_Left_Using_Frame_On_LayoutStyle_Absolute ()
 		{
 			var label = new Label ("At 0,0");
-			var view = new DerivedView () {
-				X = 2,
-				Y = 2,
-				Width = 30,
-				Height = 2,
+			var view = new DerivedView (new Rect (2, 2, 30, 2)) {
 				Text = "A text with some long width\n and also with two lines."
 			};
 			var top = Application.Top;
 			top.Add (label, view);
 			Application.Begin (top);
 
-			view.CorrectRedraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
                              
   A text with some long width
    and also with two lines.  ", output);
 
+			Assert.Equal (LayoutStyle.Absolute, view.LayoutStyle);
 			view.Frame = new Rect (1, 1, 10, 1);
+			Assert.Equal (new Rect (1, 1, 10, 1), view.Frame);
 			Assert.Equal (new Rect (0, 0, 10, 1), view.Bounds);
-			Assert.Equal (new Rect (1, 1, 31, 3), view.NeedDisplay);
-			view.CorrectRedraw (view.Bounds);
+			Assert.Equal (view.Bounds, view.NeedDisplay);
+			top.Redraw (top.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0     
  A text wit", output);
 		}
 
 		[Fact, AutoInitShutdown]
-		public void Correct_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Up_Left_Using_Pos_Dim ()
+		public void Correct_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Up_Left_Using_Pos_Dim_On_LayoutStyle_Computed ()
 		{
 			var label = new Label ("At 0,0");
 			var view = new DerivedView () {
@@ -4263,52 +4251,50 @@ At 0,0
 			top.Add (label, view);
 			Application.Begin (top);
 
-			view.CorrectRedraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
                              
   A text with some long width
    and also with two lines.  ", output);
 
+			Assert.Equal (LayoutStyle.Computed, view.LayoutStyle);
 			view.X = 1;
 			view.Y = 1;
 			view.Width = 10;
 			view.Height = 1;
 			Assert.Equal (new Rect (1, 1, 10, 1), view.Frame);
 			Assert.Equal (new Rect (0, 0, 10, 1), view.Bounds);
-			Assert.Equal (new Rect (1, 1, 31, 3), view.NeedDisplay);
-			view.CorrectRedraw (view.Bounds);
+			Assert.Equal (new Rect (0, 0, 30, 2), view.NeedDisplay);
+			top.Redraw (top.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0     
  A text wit", output);
 		}
 
 		[Fact, AutoInitShutdown]
-		public void Incorrect_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Up_Left_Using_Frame ()
+		public void Incorrect_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Up_Left_Using_FrameOn_LayoutStyle_Absolute ()
 		{
 			var label = new Label ("At 0,0");
-			var view = new DerivedView () {
-				X = 2,
-				Y = 2,
-				Width = 30,
-				Height = 2,
+			var view = new DerivedView (new Rect (2, 2, 30, 2)) {
 				Text = "A text with some long width\n and also with two lines."
 			};
 			var top = Application.Top;
 			top.Add (label, view);
 			Application.Begin (top);
 
-			view.IncorrectRedraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
                              
   A text with some long width
    and also with two lines.  ", output);
 
+			Assert.Equal (LayoutStyle.Absolute, view.LayoutStyle);
 			view.Frame = new Rect (1, 1, 10, 1);
+			Assert.Equal (new Rect (1, 1, 10, 1), view.Frame);
 			Assert.Equal (new Rect (0, 0, 10, 1), view.Bounds);
-			Assert.Equal (new Rect (1, 1, 31, 3), view.NeedDisplay);
-			view.IncorrectRedraw (view.Bounds);
+			Assert.Equal (view.Bounds, view.NeedDisplay);
+			// top needs redraw and calling view directly won't clear top.
+			view.Redraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
  A text wit                  
@@ -4317,7 +4303,7 @@ At 0,0
 		}
 
 		[Fact, AutoInitShutdown]
-		public void Incorrect_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Up_Left_Using_Pos_Dim ()
+		public void Incorrect_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Up_Left_Using_Pos_DimOn_LayoutStyle_Computed ()
 		{
 			var label = new Label ("At 0,0");
 			var view = new DerivedView () {
@@ -4331,7 +4317,6 @@ At 0,0
 			top.Add (label, view);
 			Application.Begin (top);
 
-			view.IncorrectRedraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
                              
@@ -4344,8 +4329,9 @@ At 0,0
 			view.Height = 1;
 			Assert.Equal (new Rect (1, 1, 10, 1), view.Frame);
 			Assert.Equal (new Rect (0, 0, 10, 1), view.Bounds);
-			Assert.Equal (new Rect (1, 1, 31, 3), view.NeedDisplay);
-			view.IncorrectRedraw (view.Bounds);
+			Assert.Equal (new Rect (0, 0, 30, 2), view.NeedDisplay);
+			// top needs redraw and calling view directly won't clear top.
+			view.Redraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
  A text wit                  
@@ -4354,31 +4340,29 @@ At 0,0
 		}
 
 		[Fact, AutoInitShutdown]
-		public void Correct_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Down_Right_Using_Frame ()
+		public void Correct_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Down_Right_Using_Frame_On_LayoutStyle_Absolute ()
 		{
 			var label = new Label ("At 0,0");
-			var view = new DerivedView () {
-				X = 2,
-				Y = 2,
-				Width = 30,
-				Height = 2,
+			var view = new DerivedView (new Rect (2, 2, 30, 2)) {
 				Text = "A text with some long width\n and also with two lines."
 			};
 			var top = Application.Top;
 			top.Add (label, view);
 			Application.Begin (top);
 
-			view.CorrectRedraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
                              
   A text with some long width
    and also with two lines.  ", output);
 
+			// it's LayoutStyle.Absolute so we can set the frame 
+			Assert.Equal (LayoutStyle.Absolute, view.LayoutStyle);
 			view.Frame = new Rect (3, 3, 10, 1);
+			Assert.Equal (new Rect (3, 3, 10, 1), view.Frame);
 			Assert.Equal (new Rect (0, 0, 10, 1), view.Bounds);
-			Assert.Equal (new Rect (2, 2, 30, 2), view.NeedDisplay);
-			view.CorrectRedraw (view.Bounds);
+			Assert.Equal (view.Bounds, view.NeedDisplay);
+			top.Redraw (top.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0       
              
@@ -4387,7 +4371,7 @@ At 0,0
 		}
 
 		[Fact, AutoInitShutdown]
-		public void Correct_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Down_Right_Using_Pos_Dim ()
+		public void Correct_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Down_Right_Using_Pos_Dim_On_LayoutStyle_Computed ()
 		{
 			var label = new Label ("At 0,0");
 			var view = new DerivedView () {
@@ -4401,21 +4385,21 @@ At 0,0
 			top.Add (label, view);
 			Application.Begin (top);
 
-			view.CorrectRedraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
                              
   A text with some long width
    and also with two lines.  ", output);
 
+			Assert.Equal (LayoutStyle.Computed, view.LayoutStyle);
 			view.X = 3;
 			view.Y = 3;
 			view.Width = 10;
 			view.Height = 1;
 			Assert.Equal (new Rect (3, 3, 10, 1), view.Frame);
 			Assert.Equal (new Rect (0, 0, 10, 1), view.Bounds);
-			Assert.Equal (new Rect (2, 2, 30, 2), view.NeedDisplay);
-			view.CorrectRedraw (view.Bounds);
+			Assert.Equal (new Rect (0, 0, 30, 2), view.NeedDisplay);
+			top.Redraw (top.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0       
              
@@ -4424,31 +4408,28 @@ At 0,0
 		}
 
 		[Fact, AutoInitShutdown]
-		public void Incorrect_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Down_Right_Using_Frame ()
+		public void Incorrect_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Down_Right_Using_Frame_On_LayoutStyle_Absolute ()
 		{
 			var label = new Label ("At 0,0");
-			var view = new DerivedView () {
-				X = 2,
-				Y = 2,
-				Width = 30,
-				Height = 2,
+			var view = new DerivedView (new Rect (2, 2, 30, 2)) {
 				Text = "A text with some long width\n and also with two lines."
 			};
 			var top = Application.Top;
 			top.Add (label, view);
 			Application.Begin (top);
 
-			view.IncorrectRedraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
                              
   A text with some long width
    and also with two lines.  ", output);
 
+			Assert.Equal (LayoutStyle.Absolute, view.LayoutStyle);
 			view.Frame = new Rect (3, 3, 10, 1);
 			Assert.Equal (new Rect (0, 0, 10, 1), view.Bounds);
-			Assert.Equal (new Rect (2, 2, 30, 2), view.NeedDisplay);
-			view.IncorrectRedraw (view.Bounds);
+			Assert.Equal (view.Bounds, view.NeedDisplay);
+			// top needs redraw and calling view directly won't clear top.
+			view.Redraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
                              
@@ -4457,7 +4438,7 @@ At 0,0
 		}
 
 		[Fact, AutoInitShutdown]
-		public void Incorrect_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Down_Right_Using_Pos_Dim ()
+		public void Incorrect_Redraw_Bounds_NeedDisplay_On_Shrink_And_Move_Down_Right_Using_Pos_Dim_On_LayoutStyle_Computed ()
 		{
 			var label = new Label ("At 0,0");
 			var view = new DerivedView () {
@@ -4471,21 +4452,22 @@ At 0,0
 			top.Add (label, view);
 			Application.Begin (top);
 
-			view.IncorrectRedraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
                              
   A text with some long width
    and also with two lines.  ", output);
 
+			Assert.Equal (LayoutStyle.Computed, view.LayoutStyle);
 			view.X = 3;
 			view.Y = 3;
 			view.Width = 10;
 			view.Height = 1;
 			Assert.Equal (new Rect (3, 3, 10, 1), view.Frame);
 			Assert.Equal (new Rect (0, 0, 10, 1), view.Bounds);
-			Assert.Equal (new Rect (2, 2, 30, 2), view.NeedDisplay);
-			view.IncorrectRedraw (view.Bounds);
+			Assert.Equal (new Rect (0, 0, 30, 2), view.NeedDisplay);
+			// top needs redraw and calling view directly won't clear top.
+			view.Redraw (view.Bounds);
 			TestHelpers.AssertDriverContentsWithFrameAre (@"
 At 0,0                       
                              
@@ -4493,7 +4475,6 @@ At 0,0
    A text witith two lines.  ", output);
 		}
 
-
 		[Fact, AutoInitShutdown]
 		public void Test_Nested_Views_With_Height_Equal_To_One ()
 		{
@@ -4511,7 +4492,6 @@ At 0,0
 			v.LayoutSubviews ();
 			v.Redraw (v.Bounds);
 
-
 			string looksLike =
 @"    
 111