feat: window focus borders for W11

GlazeWM.Bootstrapper/Startup.cs

@@ -5,6 +5,7 @@
 using GlazeWM.Bar;
 using GlazeWM.Domain.Common.Commands;
 using GlazeWM.Domain.Containers.Commands;
+using GlazeWM.Domain.Containers.Events;
 using GlazeWM.Domain.UserConfigs;
 using GlazeWM.Domain.UserConfigs.Commands;
 using GlazeWM.Domain.Windows;
@@ -51,6 +52,8 @@ public void Run()
         _bus.Events.OfType<ApplicationExitingEvent>()
           .Subscribe(_ => OnApplicationExit());
 
+        _bus.Events.OfType<FocusChangedEvent>().Subscribe((@event) => _bus.InvokeAsync(new SetActiveWindowBorderCommand(@event.FocusedContainer as Window)));
+
         // Launch bar WPF application. Spawns bar window when monitors are added, so the service needs
         // to be initialized before populating initial state.
         _barService.StartApp();
@@ -102,6 +105,7 @@ public void Run()
     private void OnApplicationExit()
     {
       _bus.Invoke(new ShowAllWindowsCommand());
+      _bus.Invoke(new SetActiveWindowBorderCommand(null));
       _barService.ExitApp();
       _systemTrayIcon?.Remove();
       Application.Exit();

GlazeWM.Domain/Containers/CommandHandlers/SetActiveWindowBorderHandler.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Diagnostics;
+using GlazeWM.Domain.Containers.Commands;
+using GlazeWM.Domain.UserConfigs;
+using GlazeWM.Domain.Windows;
+using GlazeWM.Infrastructure.Bussing;
+using static GlazeWM.Infrastructure.WindowsApi.WindowsApiService;
+
+namespace GlazeWM.Domain.Containers.CommandHandlers
+{
+  internal sealed class SetActiveWindowBorderHandler : ICommandHandler<SetActiveWindowBorderCommand>
+  {
+    private readonly UserConfigService _userConfigService;
+    private static Window _lastFocused;
+
+    private uint rgbToUint(string rgb)
+    {
+      var c = rgb.ToCharArray();
+      var bgr = string.Concat(c[5], c[6], c[3], c[4], c[1], c[2]);
+      return Convert.ToUInt32(bgr, 16);
+    }
+
+    public SetActiveWindowBorderHandler(UserConfigService userConfigService)
+    {
+      _userConfigService = userConfigService;
+    }
+
+    public CommandResponse Handle(SetActiveWindowBorderCommand command)
+    {
+      uint BorderColorAttribute = 34;
+      if (_lastFocused is not null)
+      {
+        uint defaultColor = 0xFFFFFFFF;
+        // Clear old window border
+        _ = DwmSetWindowAttribute(_lastFocused.Handle, BorderColorAttribute, ref defaultColor, 4);
+      }
+
+      var newWindowFocused = command.TargetWindow;
+      if (newWindowFocused is null)
+        return CommandResponse.Ok;
+
+      _lastFocused = command.TargetWindow;
+      // Set new window border
+      var configColor = rgbToUint(_userConfigService.GeneralConfig.FocusBorderColor);
+      _ = DwmSetWindowAttribute(_lastFocused.Handle, BorderColorAttribute, ref configColor, 4);
+      return CommandResponse.Ok;
+    }
+  }
+}

GlazeWM.Domain/Containers/Commands/SetActiveWindowBorderCommand.cs

@@ -0,0 +1,19 @@
+using GlazeWM.Domain.Windows;
+using GlazeWM.Infrastructure.Bussing;
+using GlazeWM.Infrastructure.WindowsApi;
+
+namespace GlazeWM.Domain.Containers.Commands
+{
+  public class SetActiveWindowBorderCommand : Command
+  {
+    public Window TargetWindow { get; }
+
+    /// <summary>
+    /// Sets the newly focused window's border and removes border on older window.  
+    /// </summary>
+    public SetActiveWindowBorderCommand(Window target)
+    {
+      TargetWindow = target;
+    }
+  }
+}

GlazeWM.Domain/DependencyInjection.cs

@@ -40,6 +40,7 @@ public static IServiceCollection AddDomainServices(this IServiceCollection servi
       services.AddSingleton<ICommandHandler<AttachAndResizeContainerCommand>, AttachAndResizeContainerHandler>();
       services.AddSingleton<ICommandHandler<AttachContainerCommand>, AttachContainerHandler>();
       services.AddSingleton<ICommandHandler<CenterCursorOnContainerCommand>, CenterCursorOnContainerHandler>();
+      services.AddSingleton<ICommandHandler<SetActiveWindowBorderCommand>, SetActiveWindowBorderHandler>();
       services.AddSingleton<ICommandHandler<ChangeContainerLayoutCommand>, ChangeContainerLayoutHandler>();
       services.AddSingleton<ICommandHandler<ToggleContainerLayoutCommand>, ToggleContainerLayoutHandler>();
       services.AddSingleton<ICommandHandler<DetachAndResizeContainerCommand>, DetachAndResizeContainerHandler>();

GlazeWM.Domain/UserConfigs/GeneralConfig.cs

@@ -19,6 +19,9 @@ public class GeneralConfig
     /// </summary>
     public string FloatingWindowMoveAmount { get; set; } = "5%";
     /// <summary>
+    /// Color for border drawn around a focused window.
+    /// </summary>
+    public string FocusBorderColor { get; set; } = "#FFFFFFFF";
     /// If activated, by switching to the current workspace the previous focused workspace is activated.
     /// </summary>
     public bool ToggleWorkspaceOnRefocus { get; set; }

GlazeWM.Domain/Windows/EventHandlers/WindowFocusedHandler.cs

@@ -7,6 +7,7 @@
 using GlazeWM.Infrastructure.Bussing;
 using GlazeWM.Infrastructure.Common.Events;
 using Microsoft.Extensions.Logging;
+using static GlazeWM.Infrastructure.WindowsApi.WindowsApiService;
 
 namespace GlazeWM.Domain.Windows.EventHandlers
 {

GlazeWM.Infrastructure/WindowsApi/WindowsApiService.cs

@@ -458,5 +458,8 @@ public struct SystemPowerStatus
       public uint BatteryLifeTime;
       public uint BatteryFullLifeTime;
     }
+
+    [DllImport("dwmapi.dll")]
+    public static extern int DwmSetWindowAttribute(IntPtr handle, uint attribute, ref uint value, uint size);
   }
 }