From f41e9939fd20f856dded79f48e87248116788b39 Mon Sep 17 00:00:00 2001
From: Roman Shapiro <eleroman@mail.ru>
Date: Mon, 23 Oct 2023 16:12:02 +0700
Subject: [PATCH] Fixes #409

---
 .../UI/Containers/SingleItemContainer.cs      | 10 +++
 src/Myra/Graphics2D/UI/TextBox.cs             | 61 ++++++++++++-------
 src/Myra/Graphics2D/UI/Widget.cs              |  4 +-
 src/Myra/Utility/InputHelpers.cs              | 24 ++++++++
 4 files changed, 74 insertions(+), 25 deletions(-)

diff --git a/src/Myra/Graphics2D/UI/Containers/SingleItemContainer.cs b/src/Myra/Graphics2D/UI/Containers/SingleItemContainer.cs
index c0f0be07..e88594a8 100644
--- a/src/Myra/Graphics2D/UI/Containers/SingleItemContainer.cs
+++ b/src/Myra/Graphics2D/UI/Containers/SingleItemContainer.cs
@@ -30,6 +30,16 @@ protected internal virtual T InternalChild
 			}
 		}
 
+		protected override void InternalArrange()
+		{
+			base.InternalArrange();
+
+			if (InternalChild != null && InternalChild.Visible)
+			{
+				InternalChild.Arrange(ActualBounds);
+			}
+		}
+
 		protected override Point InternalMeasure(Point availableSize)
 		{
 			var result = Mathematics.PointZero;
diff --git a/src/Myra/Graphics2D/UI/TextBox.cs b/src/Myra/Graphics2D/UI/TextBox.cs
index 5813c487..c30e00c0 100644
--- a/src/Myra/Graphics2D/UI/TextBox.cs
+++ b/src/Myra/Graphics2D/UI/TextBox.cs
@@ -25,6 +25,9 @@ namespace Myra.Graphics2D.UI
 {
 	public class TextBox : Widget
 	{
+		private const int CursorUpdateDelayInMs = 30;
+
+		private DateTime _lastCursorUpdate;
 		private DateTime _lastBlinkStamp = DateTime.Now;
 		private bool _cursorOn = true;
 		private bool _wrap = false;
@@ -328,6 +331,7 @@ internal set
 				if (Desktop != null)
 				{
 					Desktop.TouchUp -= DesktopTouchUp;
+					Desktop.TouchDown -= DesktopTouchDown;
 				}
 
 				base.Desktop = value;
@@ -335,11 +339,11 @@ internal set
 				if (Desktop != null)
 				{
 					Desktop.TouchUp += DesktopTouchUp;
+					Desktop.TouchDown += DesktopTouchDown;
 				}
 			}
 		}
 
-
 		/// <summary>
 		/// Fires when the value is about to be changed
 		/// Set Cancel to true if you want to cancel the change
@@ -1164,10 +1168,25 @@ public override void OnChar(char c)
 
 		private void SetCursorByTouch()
 		{
+			if (Desktop == null)
+			{
+				return;
+			}
+
 			var mousePos = ToLocal(Desktop.TouchPosition);
 			mousePos.X += _internalScrolling.X;
 			mousePos.Y += _internalScrolling.Y;
 
+			if (mousePos.X < 0)
+			{
+				mousePos.X = 0;
+			}
+
+			if (mousePos.Y < 0)
+			{
+				mousePos.Y = 0;
+			}
+
 			var line = _richTextLayout.GetLineByY(mousePos.Y);
 			if (line != null)
 			{
@@ -1186,33 +1205,24 @@ private void SetCursorByTouch()
 			}
 		}
 
-		public override bool OnTouchDown()
+		private void DesktopTouchUp(object sender, EventArgs args)
 		{
-			base.OnTouchDown();
-
-			if (!Enabled)
-			{
-				return false;
-			}
+			_isTouchDown = false;
+		}
 
-			if (Length == 0)
+		private void DesktopTouchDown(object sender, EventArgs e)
+		{
+			if (!Enabled || !IsTouchInside || Length == 0)
 			{
-				return false;
+				return;
 			}
 
 			SetCursorByTouch();
 
+			_lastCursorUpdate = DateTime.Now;
 			_isTouchDown = true;
-
-			return true;
 		}
 
-		public override void OnTouchMoved()
-		{
-			base.OnTouchMoved();
-
-			SetCursorByTouch();
-		}
 
 		public override void OnTouchDoubleClick()
 		{
@@ -1398,6 +1408,16 @@ public override void InternalRender(RenderContext context)
 				return;
 			}
 
+			if (_isTouchDown)
+			{
+				var passed = DateTime.Now - _lastCursorUpdate;
+				if (passed.TotalMilliseconds > CursorUpdateDelayInMs)
+				{
+					SetCursorByTouch();
+					_lastCursorUpdate = DateTime.Now;
+				}
+			}
+
 			var bounds = ActualBounds;
 			RenderSelection(context);
 
@@ -1540,10 +1560,5 @@ public float GetWidth(int index)
 
 			return glyph.Value.Bounds.Width;
 		}
-
-		private void DesktopTouchUp(object sender, EventArgs args)
-		{
-			_isTouchDown = false;
-		}
 	}
 }
\ No newline at end of file
diff --git a/src/Myra/Graphics2D/UI/Widget.cs b/src/Myra/Graphics2D/UI/Widget.cs
index 5f1bf404..afd3650d 100644
--- a/src/Myra/Graphics2D/UI/Widget.cs
+++ b/src/Myra/Graphics2D/UI/Widget.cs
@@ -1304,7 +1304,7 @@ protected virtual void InternalSetStyle(Stylesheet stylesheet, string name)
 
 		public virtual void OnMouseLeft()
 		{
-			ChildrenCopy.ProcessMouseMovement();
+			ChildrenCopy.ProcessMouseLeft();
 
 			MouseLeft.Invoke(this);
 		}
@@ -1338,7 +1338,7 @@ public virtual void OnMouseWheel(float delta)
 		public virtual void OnTouchLeft()
 		{
 			IsTouchInside = false;
-			ChildrenCopy.ProcessTouchMovement();
+			ChildrenCopy.ProcessTouchLeft();
 
 			TouchLeft.Invoke(this);
 		}
diff --git a/src/Myra/Utility/InputHelpers.cs b/src/Myra/Utility/InputHelpers.cs
index f9aa2161..a4f5f02b 100644
--- a/src/Myra/Utility/InputHelpers.cs
+++ b/src/Myra/Utility/InputHelpers.cs
@@ -120,6 +120,18 @@ public static void ProcessTouchDoubleClick(this List<Widget> widgets)
 			}
 		}
 
+		public static void ProcessMouseLeft(this List<Widget> widgets)
+		{
+			for (var i = widgets.Count - 1; i >= 0; --i)
+			{
+				var w = widgets[i];
+				if (w.IsMouseInside)
+				{
+					w.IsMouseInside = false;
+				}
+			}
+		}
+
 		public static void ProcessMouseMovement(this List<Widget> widgets)
 		{
 			// First run: call on OnMouseLeft on all widgets if it is required
@@ -154,6 +166,18 @@ public static void ProcessMouseMovement(this List<Widget> widgets)
 			}
 		}
 
+		public static void ProcessTouchLeft(this List<Widget> widgets)
+		{
+			for (var i = widgets.Count - 1; i >= 0; --i)
+			{
+				var w = widgets[i];
+				if (w.IsTouchInside)
+				{
+					w.OnTouchLeft();
+				}
+			}
+		}
+
 		public static void ProcessTouchMovement(this List<Widget> widgets)
 		{
 			// First run: call on OnTouchLeft on all widgets if it is required