From 841a0e359de2ed95bebd654a884b2febb65e4415 Mon Sep 17 00:00:00 2001
From: Martin Zikmund <martin@zikmund.dev>
Date: Thu, 28 Mar 2024 14:18:22 +0100
Subject: [PATCH] feat: Adjust WASM to use XamlRoot.RasterizationScale

---
 .../Factory/NativeWindowFactory.singlewindow.cs |  6 +++++-
 .../Window/Native/NativeWindowWrapper.wasm.cs   | 17 +++++++++++++++++
 .../Window/Native/NativeWindowWrapperBase.cs    |  2 +-
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/Uno.UI/UI/Xaml/Window/Native/Factory/NativeWindowFactory.singlewindow.cs b/src/Uno.UI/UI/Xaml/Window/Native/Factory/NativeWindowFactory.singlewindow.cs
index 3716bce041fc..f39066d4aae8 100644
--- a/src/Uno.UI/UI/Xaml/Window/Native/Factory/NativeWindowFactory.singlewindow.cs
+++ b/src/Uno.UI/UI/Xaml/Window/Native/Factory/NativeWindowFactory.singlewindow.cs
@@ -11,6 +11,10 @@ partial class NativeWindowFactory
 {
 	public static bool SupportsMultipleWindows => false;
 
-	private static INativeWindowWrapper? CreateWindowPlatform(Microsoft.UI.Xaml.Window window, XamlRoot xamlRoot) => NativeWindowWrapper.Instance;
+	private static INativeWindowWrapper? CreateWindowPlatform(Microsoft.UI.Xaml.Window window, XamlRoot xamlRoot)
+	{
+		NativeWindowWrapper.Instance.SetXamlRoot(xamlRoot);
+		return NativeWindowWrapper.Instance;
+	}
 }
 #endif
diff --git a/src/Uno.UI/UI/Xaml/Window/Native/NativeWindowWrapper.wasm.cs b/src/Uno.UI/UI/Xaml/Window/Native/NativeWindowWrapper.wasm.cs
index 23dedf3464e3..1c98f02ffe78 100644
--- a/src/Uno.UI/UI/Xaml/Window/Native/NativeWindowWrapper.wasm.cs
+++ b/src/Uno.UI/UI/Xaml/Window/Native/NativeWindowWrapper.wasm.cs
@@ -1,6 +1,9 @@
 using System;
+using System.Runtime.InteropServices.JavaScript;
 using Uno.Disposables;
+using Uno.Foundation.Logging;
 using Windows.Foundation;
+using Windows.Graphics.Display;
 using Windows.UI.Core;
 using static __Uno.UI.Xaml.Controls.NativeWindowWrapper;
 
@@ -10,8 +13,16 @@ internal partial class NativeWindowWrapper : NativeWindowWrapperBase
 {
 	private static readonly Lazy<NativeWindowWrapper> _instance = new(() => new NativeWindowWrapper());
 
+	private readonly DisplayInformation _displayInformation;
+
 	internal static NativeWindowWrapper Instance => _instance.Value;
 
+	public NativeWindowWrapper()
+	{
+		_displayInformation = DisplayInformation.GetForCurrentViewSafe() ?? throw new InvalidOperationException("DisplayInformation must be available when the window is initialized");
+		_displayInformation.DpiChanged += (s, e) => DispatchDpiChanged();
+	}
+
 	public override object NativeWindow => null;
 
 	public override void Activate()
@@ -22,6 +33,12 @@ public override void Close()
 	{
 	}
 
+	private void DispatchDpiChanged()
+	{
+		this.Log().LogError("Setting RasterizationScale to {0}", _displayInformation.RawPixelsPerViewPixel);
+		RasterizationScale = (float)_displayInformation.RawPixelsPerViewPixel;
+	}
+
 	internal void OnNativeClosed() => RaiseClosed();
 
 	internal void OnNativeActivated(CoreWindowActivationState state) => ActivationState = state;
diff --git a/src/Uno.UI/UI/Xaml/Window/Native/NativeWindowWrapperBase.cs b/src/Uno.UI/UI/Xaml/Window/Native/NativeWindowWrapperBase.cs
index 1ea8eb7b01d6..d05fbd914027 100644
--- a/src/Uno.UI/UI/Xaml/Window/Native/NativeWindowWrapperBase.cs
+++ b/src/Uno.UI/UI/Xaml/Window/Native/NativeWindowWrapperBase.cs
@@ -35,7 +35,7 @@ protected NativeWindowWrapperBase()
 
 	protected XamlRoot? XamlRoot => _xamlRoot;
 
-	protected void SetXamlRoot(XamlRoot xamlRoot)
+	internal void SetXamlRoot(XamlRoot xamlRoot)
 	{
 		_xamlRoot = xamlRoot;
 		xamlRoot.VisualTree.ContentRoot.SetContentIsland(_contentIsland);