Fix windows not being draggable (SubnauticaNitrox#2703)

Author: dartasen

Nitrox.Launcher/Models/Controls/CustomTitlebar.axaml

@@ -2,6 +2,7 @@
     xmlns="https://github.com/avaloniaui"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:controls="clr-namespace:Nitrox.Launcher.Models.Controls"
+    xmlns:design="clr-namespace:Nitrox.Launcher.Models.Design"
     xmlns:converters="clr-namespace:Nitrox.Launcher.Models.Converters">
     <Design.PreviewWith>
         <StackPanel Width="200">
@@ -77,6 +78,7 @@
         <Setter Property="HorizontalAlignment" Value="Stretch" />
         <Setter Property="VerticalAlignment" Value="Top" />
         <Setter Property="ShowTitle" Value="False" />
+        <Setter Property="IsVisible" Value="{Binding $parent[Window].(design:NitroxAttached.UseCustomTitleBar)}" />
 
         <Style Selector="^ /template/ StackPanel">
             <Setter Property="Orientation" Value="Horizontal" />

Nitrox.Launcher/Models/Extensions/VisualExtensions.cs

@@ -1,33 +1,44 @@
-using System.Runtime.InteropServices;
+using System;
 using Avalonia;
 using Avalonia.Controls;
+using Nitrox.Launcher.Models.Design;
 using Nitrox.Model.Platforms.OS.Windows;
 
 namespace Nitrox.Launcher.Models.Extensions;
 
 public static class VisualExtensions
 {
-    public static void ApplyOsWindowStyling(this Visual visual)
+    public static void ApplyPlatformWindowStyle(this Window window)
     {
         if (IsDesignMode)
         {
             return;
         }
-        if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+
+        if (OperatingSystem.IsLinux())
         {
-            return;
+            // On Linux systems, Avalonia has trouble allowing windows to resize without "decorations". So we enable it in full, but hide the custom titlebar as it'll look bad.
+            window.SystemDecorations = SystemDecorations.Full;
+            NitroxAttached.SetUseCustomTitleBar(window, false);
         }
-        if (visual.GetWindow() is not { } window)
+        else if (OperatingSystem.IsMacOS())
         {
-            return;
+            // On MacOS, it's uncommon to override the system titlebar
+            window.SystemDecorations = SystemDecorations.Full;
+            window.ExtendClientAreaToDecorationsHint = false;
+            window.ExtendClientAreaTitleBarHeightHint = -1;
+            NitroxAttached.SetUseCustomTitleBar(window, false);
         }
-        nint? windowHandle = window.TryGetPlatformHandle()?.Handle;
-        if (!windowHandle.HasValue)
+        else if (OperatingSystem.IsWindows())
         {
-            return;
-        }
+            nint? windowHandle = window.TryGetPlatformHandle()?.Handle;
+            if (!windowHandle.HasValue)
+            {
+                return;
+            }
 
-        WindowsApi.EnableDefaultWindowAnimations(windowHandle.Value, window.CanResize);
+            WindowsApi.EnableDefaultWindowAnimations(windowHandle.Value, window.CanResize);
+        }
     }
 
     public static Window? GetWindow(this Visual visual) => TopLevel.GetTopLevel(visual) as Window;

Nitrox.Launcher/Views/Abstract/ModalBase.cs

@@ -1,8 +1,11 @@
-using Avalonia.Controls;
+using Avalonia.Controls;
 
 namespace Nitrox.Launcher.Views.Abstract;
 
 public abstract class ModalBase : Window
 {
-    protected override void OnInitialized() => this.ApplyOsWindowStyling();
+    protected override void OnInitialized()
+    {
+        this.ApplyPlatformWindowStyle();
+    }
 }

Nitrox.Launcher/Views/Abstract/WindowEx.cs

@@ -1,6 +1,4 @@
-using System;
 using Avalonia.Controls;
-using Nitrox.Launcher.Models.Design;
 using Nitrox.Launcher.ViewModels.Abstract;
 
 namespace Nitrox.Launcher.Views.Abstract;
@@ -9,14 +7,6 @@ internal abstract class WindowEx<T> : Window where T : ViewModelBase
 {
     protected override void OnInitialized()
     {
-        this.ApplyOsWindowStyling();
-
-        // On Linux systems, Avalonia has trouble allowing windows to resize without "decorations". So we enable it in full, but hide the custom titlebar as it'll look bad.
-        // On macOS, we need the native toolbar as every app is using it
-        if (OperatingSystem.IsLinux() || OperatingSystem.IsMacOS())
-        {
-            SystemDecorations = SystemDecorations.Full;
-            NitroxAttached.SetUseCustomTitleBar(this, false);
-        }
+        this.ApplyPlatformWindowStyle();
     }
 }

Nitrox.Launcher/Views/BackupRestoreModal.axaml

@@ -4,7 +4,7 @@
     MinWidth="500"
     SizeToContent="WidthAndHeight"
     Title="{Binding Title}"
-    d:DesignHeight="450"
+    d:DesignHeight="500"
     d:DesignWidth="800"
     mc:Ignorable="d"
     x:Class="Nitrox.Launcher.Views.BackupRestoreModal"
@@ -19,7 +19,8 @@
         <vm:BackupRestoreViewModel />
     </Design.DataContext>
     <Grid RowDefinitions="Auto, *, Auto">
-        <controls:CustomTitlebar CanMinimize="False" Grid.Row="0" />
+        <controls:CustomTitlebar CanMinimize="False"
+                                 Grid.Row="0" />
 
         <TextBlock
             Classes="modalHeader"

Nitrox.Launcher/Views/CrashWindow.axaml

@@ -43,7 +43,7 @@
         </viewModels:CrashWindowViewModel>
     </Design.DataContext>
     <DockPanel LastChildFill="True">
-        <controls:CustomTitlebar DockPanel.Dock="Top" IsVisible="{Binding $parent[Window].(design:NitroxAttached.UseCustomTitleBar)}" ShowTitle="True" />
+        <controls:CustomTitlebar DockPanel.Dock="Top" ShowTitle="True" />
         <Grid RowDefinitions="*,Auto">
             <ScrollViewer>
                 <!--  TODO: Nice color highlighting (with option to click on line to open the source file?)  -->

Nitrox.Launcher/Views/DialogBoxModal.axaml

@@ -24,8 +24,7 @@
     <Grid RowDefinitions="Auto,*,Auto">
         <controls:CustomTitlebar
             CanMinimize="False"
-            Grid.RowSpan="2"
-            ShowTitle="False" />
+            Grid.RowSpan="2" />
         <TextBlock
             FontSize="{Binding TitleFontSize}"
             FontWeight="{Binding TitleFontWeight}"

Nitrox.Launcher/Views/MainWindow.axaml

@@ -178,7 +178,7 @@
     </Interaction.Behaviors>
 
     <Panel>
-        <controls:CustomTitlebar IsVisible="{Binding $parent[Window].(design:NitroxAttached.UseCustomTitleBar)}" Opacity="0.6" />
+        <controls:CustomTitlebar Opacity="0.6" />
 
         <Grid ColumnDefinitions="274,*" RowDefinitions="*">
             <!--  Navigation (left side)  -->

Nitrox.Model/Platforms/OS/Windows/WindowsApi.cs

@@ -1,17 +1,17 @@
 using System;
 using System.Runtime.InteropServices;
-using Nitrox.Model.Platforms.OS.Windows.Internal;
 using static Nitrox.Model.Platforms.OS.Windows.Internal.Win32Native;
 
 namespace Nitrox.Model.Platforms.OS.Windows;
 
-public class WindowsApi
+public static partial class WindowsApi
 {
     /// <summary>
     ///     Applies default OS animations to the window handle.
     /// </summary>
     /// <remarks>
-    ///     Note on Windows OS: it will force enable resizing of a Window if <see cref="canResize"/> is true. Make sure to set it correctly.
+    ///     Note on Windows OS: it will force enable resizing of a Window if <see cref="canResize" /> is true. Make sure to set
+    ///     it correctly.
     /// </remarks>
     public static void EnableDefaultWindowAnimations(nint windowHandle, bool canResize)
     {
@@ -20,10 +20,10 @@ public static void EnableDefaultWindowAnimations(nint windowHandle, bool canResi
             return;
         }
 
-        Win32Native.WS dwNewLong = Win32Native.WS.WS_CAPTION | Win32Native.WS.WS_CLIPCHILDREN | Win32Native.WS.WS_MINIMIZEBOX | Win32Native.WS.WS_MAXIMIZEBOX | Win32Native.WS.WS_SYSMENU;
+        WS dwNewLong = WS.WS_CAPTION | WS.WS_CLIPCHILDREN | WS.WS_MINIMIZEBOX | WS.WS_MAXIMIZEBOX | WS.WS_SYSMENU;
         if (canResize)
         {
-            dwNewLong |= Win32Native.WS.WS_SIZEBOX;
+            dwNewLong |= WS.WS_SIZEBOX;
         }
 
         HandleRef handle = new(null, windowHandle);
@@ -53,12 +53,26 @@ public static void BringProcessToFront(IntPtr windowHandle)
         SetForegroundWindow(windowHandle);
     }
 
+#if NET
+    [LibraryImport("User32.dll")]
+    [return: MarshalAs(UnmanagedType.Bool)]
+    private static partial bool SetForegroundWindow(IntPtr handle);
+
+    [LibraryImport("User32.dll")]
+    [return: MarshalAs(UnmanagedType.Bool)]
+    private static partial bool ShowWindow(IntPtr handle, int nCmdShow);
+
+    [LibraryImport("User32.dll")]
+    [return: MarshalAs(UnmanagedType.Bool)]
+    private static partial bool IsIconic(IntPtr handle);
+#else
     [DllImport("User32.dll")]
     private static extern bool SetForegroundWindow(IntPtr handle);
+
     [DllImport("User32.dll")]
     private static extern bool ShowWindow(IntPtr handle, int nCmdShow);
+
     [DllImport("User32.dll")]
     private static extern bool IsIconic(IntPtr handle);
-    [DllImport("User32.dll", CharSet = CharSet.Unicode)]
-    private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
+#endif
 }