Merge branch 'main' into 1.8

Author: niels9001

WinUIGallery/Helpers/WindowHelper.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+using Microsoft.UI.Windowing;
 using Microsoft.UI.Xaml;
 using System;
 using System.Collections.Generic;
@@ -62,6 +63,33 @@ static public double GetRasterizationScaleForElement(UIElement element)
         return 0.0;
     }
 
+    static public void SetWindowMinSize(Window window, double width, double height)
+    {
+        if (window.Content is not FrameworkElement windowContent)
+        {
+            System.Diagnostics.Debug.WriteLine("Window content is not a FrameworkElement.");
+            return;
+        }
+
+        if (windowContent.XamlRoot is null)
+        {
+            System.Diagnostics.Debug.WriteLine("Window content's XamlRoot is null.");
+            return;
+        }
+
+        if (window.AppWindow.Presenter is not OverlappedPresenter presenter)
+        {
+            System.Diagnostics.Debug.WriteLine("Window's AppWindow.Presenter is not an OverlappedPresenter.");
+            return;
+        }
+
+        var scale = windowContent.XamlRoot.RasterizationScale;
+        var minWidth = width * scale;
+        var minHeight = height * scale;
+        presenter.PreferredMinimumWidth = (int)minWidth;
+        presenter.PreferredMinimumHeight = (int)minHeight;
+    }
+
     static public List<Window> ActiveWindows { get { return _activeWindows; } }
 
     static private List<Window> _activeWindows = new List<Window>();

WinUIGallery/MainWindow.xaml.cs

@@ -36,16 +36,29 @@ public MainWindow()
     {
         this.InitializeComponent();
         SetWindowProperties();
-        RootGrid.ActualThemeChanged += (_,_) => TitleBarHelper.ApplySystemThemeToCaptionButtons(this, RootGrid.ActualTheme);
+        RootGrid.ActualThemeChanged += (_, _) => TitleBarHelper.ApplySystemThemeToCaptionButtons(this, RootGrid.ActualTheme);
         dispatcherQueue = Microsoft.UI.Dispatching.DispatcherQueue.GetForCurrentThread();
     }
 
     private void RootGrid_Loaded(object sender, RoutedEventArgs e)
     {
+        // We need to set the minimum size here because the XamlRoot is not available in the constructor.
+        WindowHelper.SetWindowMinSize(this, 640, 500);
+
+        if (sender is FrameworkElement rootGrid && rootGrid.XamlRoot is not null)
+        {
+            rootGrid.XamlRoot.Changed += RootGridXamlRoot_Changed;
+        }
+
         NavigationOrientationHelper.UpdateNavigationViewForElement(NavigationOrientationHelper.IsLeftMode());
         TitleBarHelper.ApplySystemThemeToCaptionButtons(this, RootGrid.ActualTheme);
     }
 
+    private void RootGridXamlRoot_Changed(XamlRoot sender, XamlRootChangedEventArgs args)
+    {
+        WindowHelper.SetWindowMinSize(this, 640, 500);
+    }
+
     private void SetWindowProperties()
     {
 #if DEBUG
@@ -58,9 +71,6 @@ private void SetWindowProperties()
         this.SetTitleBar(titleBar);
         this.AppWindow.SetIcon("Assets/Tiles/GalleryIcon.ico");
         this.AppWindow.TitleBar.PreferredHeightOption = TitleBarHeightOption.Tall;
-
-        Win32WindowHelper win32WindowHelper = new Win32WindowHelper(this);
-        win32WindowHelper.SetWindowMinMaxSize(new Win32WindowHelper.POINT() { x = 640, y = 500 });
     }
 
     private void OnPaneDisplayModeChanged(NavigationView sender, NavigationViewDisplayModeChangedEventArgs args)