Support for color scheme change

Author: Jack251970

Flow.Launcher.Infrastructure/Win32Helper.cs

@@ -801,16 +801,22 @@ public static unsafe void OpenFolderAndSelectFile(string filePath)
         [DllImport("uxtheme.dll", EntryPoint = "#135", SetLastError = true)]
         private static extern int SetPreferredAppMode(int appMode);
 
-        public static void EnableWin32DarkMode()
+        public static void EnableWin32DarkMode(string colorScheme)
         {
             try
             {
-                // From Windows 10 1809
-                // AppMode: 0=Default, 1=AllowDark, 2=ForceDark, 3=ForceLight, 4=Max
+                // Undocumented API from Windows 10 1809
                 if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) &&
                     Environment.OSVersion.Version.Build >= 17763)
                 {
-                    _ = SetPreferredAppMode(1);
+                    var flag = colorScheme switch
+                    {
+                        Constant.Light => 3, // ForceLight
+                        Constant.Dark => 2, // ForceDark
+                        Constant.System => 1, // AllowDark
+                        _ => 0 // Default
+                    };
+                    _ = SetPreferredAppMode(flag);
                 }
 
             }

Flow.Launcher/App.xaml.cs

@@ -189,7 +189,7 @@ await API.StopwatchLogInfoAsync(ClassName, "Startup cost", async () =>
                 Notification.Install();
 
                 // Enable Win32 dark mode if the system is in dark mode before creating all windows
-                Win32Helper.EnableWin32DarkMode();
+                Win32Helper.EnableWin32DarkMode(_settings.ColorScheme);
 
                 Ioc.Default.GetRequiredService<Portable>().PreStartCleanUpAfterPortabilityUpdate();
 

Flow.Launcher/SettingPages/ViewModels/SettingsPaneThemeViewModel.cs

@@ -136,6 +136,7 @@ public string ColorScheme
             };
             Settings.ColorScheme = value;
             _ = _theme.RefreshFrameAsync();
+            Win32Helper.EnableWin32DarkMode(value);
         }
     }