From b7f0f99b4d37fdcd110d87c05b2ce2d025639cfb Mon Sep 17 00:00:00 2001
From: Jakub Florkowski <kubaflo123@gmail.com>
Date: Sat, 2 Mar 2024 15:32:42 +0100
Subject: [PATCH] [iOS] Shell/NavigationPage TitleView (#5063)

---
 .../NavigationPage/iOS/NavigationRenderer.cs  | 48 ++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/src/Controls/src/Core/Compatibility/Handlers/NavigationPage/iOS/NavigationRenderer.cs b/src/Controls/src/Core/Compatibility/Handlers/NavigationPage/iOS/NavigationRenderer.cs
index 61f6fece69ed..2832dff39d2e 100644
--- a/src/Controls/src/Core/Compatibility/Handlers/NavigationPage/iOS/NavigationRenderer.cs
+++ b/src/Controls/src/Core/Compatibility/Handlers/NavigationPage/iOS/NavigationRenderer.cs
@@ -22,6 +22,7 @@
 using RectangleF = CoreGraphics.CGRect;
 using SizeF = CoreGraphics.CGSize;
 using Microsoft.Maui.Platform;
+using Microsoft.Maui.Layouts;
 
 namespace Microsoft.Maui.Controls.Handlers.Compatibility
 {
@@ -1765,6 +1766,7 @@ class Container : UIView
 			IPlatformViewHandler _child;
 			UIImageView _icon;
 			bool _disposed;
+			const int SystemMargin = 16;
 
 			public Container(View view, UINavigationBar bar) : base(bar.Bounds)
 			{
@@ -1796,6 +1798,44 @@ public Container(View view, UINavigationBar bar) : base(bar.Bounds)
 				ClipsToBounds = true;
 			}
 
+			// A solution based on this code https://github.dev/devxoul/UINavigationItem-Margin
+			// responsible for removing the system margin inside the navigation bar
+			UIEdgeInsets CalculateUIEdgeInsets()
+			{
+				var type = UIBarButtonSystemItem.FixedSpace;
+				var spacer = new UIBarButtonItem(type, (_, _) => { });
+
+				if (UIDevice.CurrentDevice.CheckSystemVersion(11, 0))
+				{
+					spacer.Width = SystemMargin + 8;
+				}
+				else
+				{
+					spacer.Width = SystemMargin - 16;
+				}
+
+				nfloat screenWidth = UIScreen.MainScreen.Bounds.Size.Width;
+
+				// A margin of private class `UINavigationButton` is different from custom view
+				if (!UIDevice.CurrentDevice.CheckSystemVersion(11, 0) && screenWidth < 375)
+				{
+					// 3.5 and 4 inch
+					spacer.Width += 8;
+				}
+				else if (screenWidth >= 414)
+				{
+					// 5.5 inch
+					spacer.Width -= 4;
+				}
+
+				return new UIEdgeInsets(0, spacer.Width, 0, spacer.Width);
+			}
+
+			public override UIEdgeInsets AlignmentRectInsets
+			{
+				get => CalculateUIEdgeInsets();
+			}
+
 			void OnTitleViewParentSet(object sender, EventArgs e)
 			{
 				if (sender is View view)
@@ -1892,10 +1932,16 @@ public override void LayoutSubviews()
 				if (_icon != null)
 					_icon.Frame = new RectangleF(0, 0, IconWidth, Math.Min(toolbarHeight, IconHeight));
 
-				if (_child?.VirtualView != null)
+				if (_child?.VirtualView is IView view)
 				{
 					Rect layoutBounds = new Rect(IconWidth, 0, Bounds.Width - IconWidth, height);
 
+					if (view.HorizontalLayoutAlignment != Primitives.LayoutAlignment.Fill ||
+						view.VerticalLayoutAlignment != Primitives.LayoutAlignment.Fill)
+					{
+						view.Measure(Bounds.Width, Bounds.Height);
+						layoutBounds = view.ComputeFrame(new Rect(0, 0, Bounds.Width, Bounds.Height));
+					}
 					_child.PlatformArrangeHandler(layoutBounds);
 				}
 				else if (_icon != null && Superview != null)