feat: Add support for XamlRoot.RasterizationScale

src/SamplesApp/UITests.Shared/UITests.Shared.projitems

@@ -1025,6 +1025,10 @@
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
     </Page>
+    <Page Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml\XamlRoot\XamlRoot_Properties.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml\xBindTests\NoPhaseBinding_Large.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
@@ -5156,6 +5160,9 @@
     <Compile Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml\WindowTests\Window_ContentIsFullyVisible.xaml.cs">
       <DependentUpon>Window_ContentIsFullyVisible.xaml</DependentUpon>
     </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml\XamlRoot\XamlRoot_Properties.xaml.cs">
+      <DependentUpon>XamlRoot_Properties.xaml</DependentUpon>
+    </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml\xBindTests\NoPhaseBinding_Large.xaml.cs">
       <DependentUpon>NoPhaseBinding_Large.xaml</DependentUpon>
     </Compile>

src/SamplesApp/UITests.Shared/Windows_UI_Xaml/XamlRoot/XamlRoot_Properties.xaml

@@ -0,0 +1,17 @@
+<UserControl
+    x:Class="UITests.Windows_UI_Xaml.XamlRoot.XamlRoot_Properties"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:UITests.Windows_UI_Xaml.XamlRoot"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d"
+    d:DesignHeight="300"
+    d:DesignWidth="400">
+
+	<StackPanel>
+		<TextBlock>
+			RasterizationScale: <Run x:Name="rasterizationScale" />
+		</TextBlock>
+	</StackPanel>
+</UserControl>

src/SamplesApp/UITests.Shared/Windows_UI_Xaml/XamlRoot/XamlRoot_Properties.xaml.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Runtime.InteropServices.WindowsRuntime;
+using Uno.UI.Samples.Controls;
+using Windows.Foundation;
+using Windows.Foundation.Collections;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Controls.Primitives;
+using Windows.UI.Xaml.Data;
+using Windows.UI.Xaml.Input;
+using Windows.UI.Xaml.Media;
+using Windows.UI.Xaml.Navigation;
+
+// The User Control item template is documented at https://go.microsoft.com/fwlink/?LinkId=234236
+
+namespace UITests.Windows_UI_Xaml.XamlRoot
+{
+	[Sample("XamlRoot", Description = "")]
+	public sealed partial class XamlRoot_Properties : UserControl
+	{
+		public XamlRoot_Properties()
+		{
+			this.InitializeComponent();
+
+			Loaded += (s, e) => {
+				rasterizationScale.Text = XamlRoot.RasterizationScale.ToString();
+			};
+		}
+	}
+}

src/Uno.UI/Generated/3.0.0.0/Windows.UI.Xaml/XamlRoot.cs

@@ -18,16 +18,6 @@ public  bool IsHostVisible
 			}
 		}
 		#endif
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
-		[global::Uno.NotImplemented("__ANDROID__", "__IOS__", "NET461", "__WASM__", "__SKIA__", "__NETSTD_REFERENCE__", "__MACOS__")]
-		public  double RasterizationScale
-		{
-			get
-			{
-				throw new global::System.NotImplementedException("The member double XamlRoot.RasterizationScale is not implemented in Uno.");
-			}
-		}
-		#endif
 		// Skipping already declared property Size
 		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
 		[global::Uno.NotImplemented("__ANDROID__", "__IOS__", "NET461", "__WASM__", "__SKIA__", "__NETSTD_REFERENCE__", "__MACOS__")]

src/Uno.UI/UI/Xaml/XamlRoot.cs

@@ -24,6 +24,9 @@ public sealed partial class XamlRoot
 
 		public Size Size => Content?.RenderSize ?? Size.Empty;
 
+		public double RasterizationScale
+			=> global::Windows.Graphics.Display.DisplayInformation.GetForCurrentView().RawPixelsPerViewPixel;
+
 		internal void NotifyChanged()
 		{
 			Changed?.Invoke(this, new XamlRootChangedEventArgs());