Implemented basic display / sleep mode handling and added logging to taskbar.

SafeExamBrowser.Configuration/BrowserSettings.cs

@@ -10,7 +10,7 @@ using System;
 using System.IO;
 using SafeExamBrowser.Contracts.Configuration.Settings;
 
-namespace SafeExamBrowser.Configuration.Settings
+namespace SafeExamBrowser.Configuration
 {
 	public class BrowserSettings : IBrowserSettings
 	{

SafeExamBrowser.Configuration/KeyboardSettings.cs

@@ -8,7 +8,7 @@
 
 using SafeExamBrowser.Contracts.Configuration.Settings;
 
-namespace SafeExamBrowser.Configuration.Settings
+namespace SafeExamBrowser.Configuration
 {
 	public class KeyboardSettings : IKeyboardSettings
 	{

SafeExamBrowser.Configuration/MouseSettings.cs

@@ -8,12 +8,12 @@
 
 using SafeExamBrowser.Contracts.Configuration.Settings;
 
-namespace SafeExamBrowser.Configuration.Settings
+namespace SafeExamBrowser.Configuration
 {
 	public class MouseSettings : IMouseSettings
 	{
 		public bool AllowMiddleButton => false;
 
-		public bool AllowRightButton => false;
+		public bool AllowRightButton => true;
 	}
 }

SafeExamBrowser.Configuration/SafeExamBrowser.Configuration.csproj

@@ -60,12 +60,10 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="Bounds.cs" />
-    <Compile Include="Settings\BrowserSettings.cs" />
-    <Compile Include="Settings\KeyboardSettings.cs" />
-    <Compile Include="Settings\MouseSettings.cs" />
-    <Compile Include="Settings\SettingsImpl.cs" />
-    <Compile Include="WorkingArea.cs" />
+    <Compile Include="BrowserSettings.cs" />
+    <Compile Include="KeyboardSettings.cs" />
+    <Compile Include="MouseSettings.cs" />
+    <Compile Include="Settings.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <ItemGroup>

SafeExamBrowser.Configuration/Settings.cs

@@ -9,7 +9,6 @@
 using System;
 using System.IO;
 using System.Reflection;
-using SafeExamBrowser.Configuration.Settings;
 using SafeExamBrowser.Contracts.Configuration.Settings;
 
 namespace SafeExamBrowser.Configuration
@@ -17,11 +16,11 @@ namespace SafeExamBrowser.Configuration
 	/// <remarks>
 	/// TODO: Replace with proper implementation once configuration aspects are clear...
 	/// </remarks>
-	public class SettingsImpl : ISettings
+	public class Settings : ISettings
 	{
 		private static readonly string LogFileDate = DateTime.Now.ToString("yyyy-MM-dd\\_HH\\hmm\\mss\\s");
 
-		public SettingsImpl()
+		public Settings()
 		{
 			Browser = new BrowserSettings(this);
 			Keyboard = new KeyboardSettings();

SafeExamBrowser.Configuration/WorkingArea.cs

@@ -1,62 +0,0 @@
-/*
- * Copyright (c) 2017 ETH Zürich, Educational Development and Technology (LET)
- * 
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/.
- */
-
-using System.Windows.Forms;
-using SafeExamBrowser.Contracts.Configuration;
-using SafeExamBrowser.Contracts.Logging;
-using SafeExamBrowser.Contracts.UserInterface;
-using SafeExamBrowser.Contracts.WindowsApi;
-
-namespace SafeExamBrowser.Configuration
-{
-	public class WorkingArea : IWorkingArea
-	{
-		private ILogger logger;
-		private INativeMethods nativeMethods;
-		private IBounds originalWorkingArea;
-
-		public WorkingArea(ILogger logger, INativeMethods nativeMethods)
-		{
-			this.logger = logger;
-			this.nativeMethods = nativeMethods;
-		}
-
-		public void InitializeFor(ITaskbar taskbar)
-		{
-			originalWorkingArea = nativeMethods.GetWorkingArea();
-
-			LogWorkingArea("Saved original working area", originalWorkingArea);
-
-			var area = new Bounds
-			{
-				Left = 0,
-				Top = 0,
-				Right = Screen.PrimaryScreen.Bounds.Width,
-				Bottom = Screen.PrimaryScreen.Bounds.Height - taskbar.GetAbsoluteHeight()
-			};
-
-			LogWorkingArea("Trying to set new working area", area);
-			nativeMethods.SetWorkingArea(area);
-			LogWorkingArea("Working area is now set to", nativeMethods.GetWorkingArea());
-		}
-
-		public void Reset()
-		{
-			if (originalWorkingArea != null)
-			{
-				nativeMethods.SetWorkingArea(originalWorkingArea);
-				LogWorkingArea("Restored original working area", originalWorkingArea);
-			}
-		}
-
-		private void LogWorkingArea(string message, IBounds area)
-		{
-			logger.Info($"{message}: Left = {area.Left}, Top = {area.Top}, Right = {area.Right}, Bottom = {area.Bottom}.");
-		}
-	}
-}

SafeExamBrowser.Contracts/Configuration/IWorkingArea.cs

@@ -1,25 +0,0 @@
-/*
- * Copyright (c) 2017 ETH Zürich, Educational Development and Technology (LET)
- * 
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/.
- */
-
-using SafeExamBrowser.Contracts.UserInterface;
-
-namespace SafeExamBrowser.Contracts.Configuration
-{
-	public interface IWorkingArea
-	{
-		/// <summary>
-		/// Sets the Windows working area to accommodate to the taskbar's dimensions.
-		/// </summary>
-		void InitializeFor(ITaskbar taskbar);
-
-		/// <summary>
-		/// Resets the Windows working area to its previous (initial) state.
-		/// </summary>
-		void Reset();
-	}
-}

SafeExamBrowser.Contracts/Monitoring/IDisplayMonitor.cs

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2017 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+namespace SafeExamBrowser.Contracts.Monitoring
+{
+	public delegate void DisplayChangedEventHandler();
+
+	public interface IDisplayMonitor
+	{
+		/// <summary>
+		/// Event fired when the primary display or its settings have changed.
+		/// </summary>
+		event DisplayChangedEventHandler DisplayChanged;
+		
+		/// <summary>
+		/// Sets the desktop working area to accommodate to the taskbar's height, removes the configured wallpaper (if possible) and
+		/// prevents the computer from entering sleep mode or turning its display(s) off.
+		/// </summary>
+		void InitializePrimaryDisplay(int taskbarHeight);
+
+		/// <summary>
+		/// Resets the desktop working area and wallpaper to their previous (initial) state.
+		/// </summary>
+		void ResetPrimaryDisplay();
+
+		/// <summary>
+		/// Starts monitoring for display changes, i.e. display changes will trigger the <c>DisplaySettingsChanged</c> event.
+		/// </summary>
+		void StartMonitoringDisplayChanges();
+
+		/// <summary>
+		/// Stops monitoring for display changes.
+		/// </summary>
+		void StopMonitoringDisplayChanges();
+	}
+}

SafeExamBrowser.Contracts/SafeExamBrowser.Contracts.csproj

@@ -72,7 +72,6 @@
     <Compile Include="Configuration\Settings\ISettings.cs" />
     <Compile Include="Behaviour\IShutdownController.cs" />
     <Compile Include="Behaviour\IStartupController.cs" />
-    <Compile Include="Configuration\IWorkingArea.cs" />
     <Compile Include="I18n\IText.cs" />
     <Compile Include="I18n\TextKey.cs" />
     <Compile Include="Logging\ILogContent.cs" />
@@ -83,6 +82,7 @@
     <Compile Include="Logging\ILogText.cs" />
     <Compile Include="Logging\IThreadInfo.cs" />
     <Compile Include="Logging\LogLevel.cs" />
+    <Compile Include="Monitoring\IDisplayMonitor.cs" />
     <Compile Include="Monitoring\IKeyboardInterceptor.cs" />
     <Compile Include="Monitoring\IMouseInterceptor.cs" />
     <Compile Include="Monitoring\IProcessMonitor.cs" />

SafeExamBrowser.Contracts/WindowsApi/INativeMethods.cs

@@ -38,6 +38,11 @@ namespace SafeExamBrowser.Contracts.WindowsApi
 		/// </exception>
 		void DeregisterSystemEvent(IntPtr handle);
 
+		/// <summary>
+		/// Prevents Windows from entering sleep mode and keeps all displays powered on.
+		/// </summary>
+		void DisableSleep();
+
 		/// <summary>
 		/// Empties the clipboard.
 		/// </summary>
@@ -72,8 +77,15 @@ namespace SafeExamBrowser.Contracts.WindowsApi
 		uint GetShellProcessId();
 
 		/// <summary>
-		/// Retrieves the title of the specified window, or an empty string, if the
-		/// given window does not have a title.
+		/// Retrieves the path of the currently configured wallpaper image, or an empty string, if there is no wallpaper set.
+		/// </summary>
+		/// <exception cref="System.ComponentModel.Win32Exception">
+		/// If the wallpaper path could not be retrieved.
+		/// </exception>
+		string GetWallpaperPath();
+
+		/// <summary>
+		/// Retrieves the title of the specified window, or an empty string, if the given window does not have a title.
 		/// </summary>
 		string GetWindowTitle(IntPtr window);
 
@@ -125,6 +137,14 @@ namespace SafeExamBrowser.Contracts.WindowsApi
 		/// </summary>
 		IntPtr RegisterSystemCaptureStartEvent(Action<IntPtr> callback);
 
+		/// <summary>
+		/// Removes the currently configured desktop wallpaper.
+		/// </summary>
+		/// <exception cref="System.ComponentModel.Win32Exception">
+		/// If the wallpaper could not be removed.
+		/// </exception>
+		void RemoveWallpaper();
+
 		/// <summary>
 		/// Restores the specified window to its original size and position.
 		/// </summary>
@@ -135,6 +155,14 @@ namespace SafeExamBrowser.Contracts.WindowsApi
 		/// </summary>
 		void SendCloseMessageTo(IntPtr window);
 
+		/// <summary>
+		/// Sets the wallpaper to the image located at the specified file path.
+		/// </summary>
+		/// <exception cref="System.ComponentModel.Win32Exception">
+		/// If the wallpaper could not be set.
+		/// </exception>
+		void SetWallpaper(string filePath);
+
 		/// <summary>
 		/// Sets the working area of the primary screen according to the given dimensions.
 		/// </summary>

SafeExamBrowser.Core.UnitTests/Behaviour/RuntimeControllerTests.cs

@@ -10,7 +10,6 @@ using System;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Moq;
 using SafeExamBrowser.Contracts.Behaviour;
-using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.Logging;
 using SafeExamBrowser.Contracts.Monitoring;
 using SafeExamBrowser.Contracts.UserInterface;
@@ -21,33 +20,52 @@ namespace SafeExamBrowser.Core.UnitTests.Behaviour
 	[TestClass]
 	public class RuntimeControllerTests
 	{
+		private Mock<IDisplayMonitor> displayMonitorMock;
 		private Mock<ILogger> loggerMock;
 		private Mock<IProcessMonitor> processMonitorMock;
 		private Mock<ITaskbar> taskbarMock;
 		private Mock<IWindowMonitor> windowMonitorMock;
-		private Mock<IWorkingArea> workingAreaMock;
 
 		private IRuntimeController sut;
 
 		[TestInitialize]
 		public void Initialize()
 		{
+			displayMonitorMock = new Mock<IDisplayMonitor>();
 			loggerMock = new Mock<ILogger>();
 			processMonitorMock = new Mock<IProcessMonitor>();
 			taskbarMock = new Mock<ITaskbar>();
 			windowMonitorMock= new Mock<IWindowMonitor>();
-			workingAreaMock = new Mock<IWorkingArea>();
 
 			sut = new RuntimeController(
+				displayMonitorMock.Object,
 				loggerMock.Object,
 				processMonitorMock.Object,
 				taskbarMock.Object,
-				windowMonitorMock.Object,
-				workingAreaMock.Object);
+				windowMonitorMock.Object);
 
 			sut.Start();
 		}
 
+		[TestMethod]
+		public void MustHandleDisplayChangeCorrectly()
+		{
+			var order = 0;
+			var workingArea = 0;
+			var taskbar = 0;
+
+			displayMonitorMock.Setup(w => w.InitializePrimaryDisplay(taskbarMock.Object.GetAbsoluteHeight())).Callback(() => workingArea = ++order);
+			taskbarMock.Setup(t => t.InitializeBounds()).Callback(() => taskbar = ++order);
+
+			displayMonitorMock.Raise(d => d.DisplayChanged += null);
+
+			displayMonitorMock.Verify(w => w.InitializePrimaryDisplay(taskbarMock.Object.GetAbsoluteHeight()), Times.Once);
+			taskbarMock.Verify(t => t.InitializeBounds(), Times.Once);
+
+			Assert.IsTrue(workingArea == 1);
+			Assert.IsTrue(taskbar == 2);
+		}
+
 		[TestMethod]
 		public void MustHandleExplorerStartCorrectly()
 		{
@@ -57,13 +75,13 @@ namespace SafeExamBrowser.Core.UnitTests.Behaviour
 			var taskbar = 0;
 
 			processMonitorMock.Setup(p => p.CloseExplorerShell()).Callback(() => processManager = ++order);
-			workingAreaMock.Setup(w => w.InitializeFor(taskbarMock.Object)).Callback(() => workingArea = ++order);
+			displayMonitorMock.Setup(w => w.InitializePrimaryDisplay(taskbarMock.Object.GetAbsoluteHeight())).Callback(() => workingArea = ++order);
 			taskbarMock.Setup(t => t.InitializeBounds()).Callback(() => taskbar = ++order);
 
 			processMonitorMock.Raise(p => p.ExplorerStarted += null);
 
 			processMonitorMock.Verify(p => p.CloseExplorerShell(), Times.Once);
-			workingAreaMock.Verify(w => w.InitializeFor(taskbarMock.Object), Times.Once);
+			displayMonitorMock.Verify(w => w.InitializePrimaryDisplay(taskbarMock.Object.GetAbsoluteHeight()), Times.Once);
 			taskbarMock.Verify(t => t.InitializeBounds(), Times.Once);
 
 			Assert.IsTrue(processManager == 1);

SafeExamBrowser.Core/Behaviour/Operations/DisplayMonitorOperation.cs

@@ -7,26 +7,26 @@
  */
 
 using SafeExamBrowser.Contracts.Behaviour;
-using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.I18n;
 using SafeExamBrowser.Contracts.Logging;
+using SafeExamBrowser.Contracts.Monitoring;
 using SafeExamBrowser.Contracts.UserInterface;
 
 namespace SafeExamBrowser.Core.Behaviour.Operations
 {
-	public class WorkingAreaOperation : IOperation
+	public class DisplayMonitorOperation : IOperation
 	{
+		private IDisplayMonitor displayMonitor;
 		private ILogger logger;
 		private ITaskbar taskbar;
-		private IWorkingArea workingArea;
 
 		public ISplashScreen SplashScreen { private get; set; }
 
-		public WorkingAreaOperation(ILogger logger, ITaskbar taskbar, IWorkingArea workingArea)
+		public DisplayMonitorOperation(IDisplayMonitor displayMonitor, ILogger logger, ITaskbar taskbar)
 		{
+			this.displayMonitor = displayMonitor;
 			this.logger = logger;
 			this.taskbar = taskbar;
-			this.workingArea = workingArea;
 		}
 
 		public void Perform()
@@ -34,10 +34,8 @@ namespace SafeExamBrowser.Core.Behaviour.Operations
 			logger.Info("Initializing working area...");
 			SplashScreen.UpdateText(TextKey.SplashScreen_InitializeWorkingArea);
 
-			// TODO
-			// - Emptying clipboard
-
-			workingArea.InitializeFor(taskbar);
+			displayMonitor.InitializePrimaryDisplay(taskbar.GetAbsoluteHeight());
+			displayMonitor.StartMonitoringDisplayChanges();
 		}
 
 		public void Revert()
@@ -45,10 +43,8 @@ namespace SafeExamBrowser.Core.Behaviour.Operations
 			logger.Info("Restoring working area...");
 			SplashScreen.UpdateText(TextKey.SplashScreen_RestoreWorkingArea);
 
-			// TODO
-			// - Emptying clipboard
-
-			workingArea.Reset();
+			displayMonitor.StopMonitoringDisplayChanges();
+			displayMonitor.ResetPrimaryDisplay();
 		}
 	}
 }

SafeExamBrowser.Core/Behaviour/RuntimeController.cs

@@ -8,7 +8,6 @@
 
 using System;
 using SafeExamBrowser.Contracts.Behaviour;
-using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.Logging;
 using SafeExamBrowser.Contracts.Monitoring;
 using SafeExamBrowser.Contracts.UserInterface;
@@ -17,28 +16,29 @@ namespace SafeExamBrowser.Core.Behaviour
 {
 	public class RuntimeController : IRuntimeController
 	{
+		private IDisplayMonitor displayMonitor;
 		private ILogger logger;
 		private IProcessMonitor processMonitor;
 		private ITaskbar taskbar;
 		private IWindowMonitor windowMonitor;
-		private IWorkingArea workingArea;
 
 		public RuntimeController(
+			IDisplayMonitor displayMonitor,
 			ILogger logger,
 			IProcessMonitor processMonitor,
 			ITaskbar taskbar,
-			IWindowMonitor windowMonitor,
-			IWorkingArea workingArea)
+			IWindowMonitor windowMonitor)
 		{
+			this.displayMonitor = displayMonitor;
 			this.logger = logger;
 			this.processMonitor = processMonitor;
 			this.taskbar = taskbar;
 			this.windowMonitor = windowMonitor;
-			this.workingArea = workingArea;
 		}
 
 		public void Start()
 		{
+			displayMonitor.DisplayChanged += DisplayMonitor_DisplaySettingsChanged;
 			processMonitor.ExplorerStarted += ProcessMonitor_ExplorerStarted;
 			windowMonitor.WindowChanged += WindowMonitor_WindowChanged;
 		}
@@ -49,12 +49,21 @@ namespace SafeExamBrowser.Core.Behaviour
 			windowMonitor.WindowChanged -= WindowMonitor_WindowChanged;
 		}
 
+		private void DisplayMonitor_DisplaySettingsChanged()
+		{
+			logger.Info("Reinitializing working area...");
+			displayMonitor.InitializePrimaryDisplay(taskbar.GetAbsoluteHeight());
+			logger.Info("Reinitializing taskbar bounds...");
+			taskbar.InitializeBounds();
+			logger.Info("Desktop successfully restored.");
+		}
+
 		private void ProcessMonitor_ExplorerStarted()
 		{
 			logger.Info("Trying to shut down explorer...");
 			processMonitor.CloseExplorerShell();
 			logger.Info("Reinitializing working area...");
-			workingArea.InitializeFor(taskbar);
+			displayMonitor.InitializePrimaryDisplay(taskbar.GetAbsoluteHeight());
 			logger.Info("Reinitializing taskbar bounds...");
 			taskbar.InitializeBounds();
 			logger.Info("Desktop successfully restored.");

SafeExamBrowser.Core/SafeExamBrowser.Core.csproj

@@ -67,7 +67,7 @@
     <Compile Include="Behaviour\Operations\ProcessMonitorOperation.cs" />
     <Compile Include="Behaviour\Operations\TaskbarOperation.cs" />
     <Compile Include="Behaviour\Operations\WindowMonitorOperation.cs" />
-    <Compile Include="Behaviour\Operations\WorkingAreaOperation.cs" />
+    <Compile Include="Behaviour\Operations\DisplayMonitorOperation.cs" />
     <Compile Include="Behaviour\ShutdownController.cs" />
     <Compile Include="Behaviour\StartupController.cs" />
     <Compile Include="Logging\DefaultLogFormatter.cs" />

SafeExamBrowser.Monitoring/Display/Bounds.cs

@@ -8,7 +8,7 @@
 
 using SafeExamBrowser.Contracts.WindowsApi;
 
-namespace SafeExamBrowser.Configuration
+namespace SafeExamBrowser.Monitoring.Display
 {
 	internal class Bounds : IBounds
 	{

SafeExamBrowser.Monitoring/Display/DisplayMonitor.cs

@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2017 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System;
+using System.Windows.Forms;
+using Microsoft.Win32;
+using SafeExamBrowser.Contracts.Logging;
+using SafeExamBrowser.Contracts.Monitoring;
+using SafeExamBrowser.Contracts.WindowsApi;
+
+namespace SafeExamBrowser.Monitoring.Display
+{
+	public class DisplayMonitor : IDisplayMonitor
+	{
+		private IBounds originalWorkingArea;
+		private ILogger logger;
+		private INativeMethods nativeMethods;
+		private string wallpaper;
+
+		public event DisplayChangedEventHandler DisplayChanged;
+
+		public DisplayMonitor(ILogger logger, INativeMethods nativeMethods)
+		{
+			this.logger = logger;
+			this.nativeMethods = nativeMethods;
+		}
+
+		public void InitializePrimaryDisplay(int taskbarHeight)
+		{
+			InitializeWorkingArea(taskbarHeight);
+			InitializeWallpaper();
+			PreventSleepMode();
+		}
+
+		public void ResetPrimaryDisplay()
+		{
+			ResetWorkingArea();
+			ResetWallpaper();
+		}
+
+		public void StartMonitoringDisplayChanges()
+		{
+			SystemEvents.DisplaySettingsChanged += SystemEvents_DisplaySettingsChanged;
+			logger.Info("Started monitoring display changes.");
+		}
+
+		public void StopMonitoringDisplayChanges()
+		{
+			SystemEvents.DisplaySettingsChanged -= SystemEvents_DisplaySettingsChanged;
+			logger.Info("Stopped monitoring display changes.");
+		}
+
+		private void SystemEvents_DisplaySettingsChanged(object sender, EventArgs e)
+		{
+			logger.Info("Display change detected!");
+			DisplayChanged?.Invoke();
+		}
+
+		private void InitializeWorkingArea(int taskbarHeight)
+		{
+			var identifier = GetIdentifierForPrimaryDisplay();
+
+			originalWorkingArea = nativeMethods.GetWorkingArea();
+			LogWorkingArea($"Saved original working area for {identifier}", originalWorkingArea);
+
+			var area = new Bounds
+			{
+				Left = 0,
+				Top = 0,
+				Right = Screen.PrimaryScreen.Bounds.Width,
+				Bottom = Screen.PrimaryScreen.Bounds.Height - taskbarHeight
+			};
+
+			LogWorkingArea($"Trying to set new working area for {identifier}", area);
+			nativeMethods.SetWorkingArea(area);
+			LogWorkingArea($"Working area of {identifier} is now set to", nativeMethods.GetWorkingArea());
+		}
+
+		private void InitializeWallpaper()
+		{
+			var path = nativeMethods.GetWallpaperPath();
+
+			if (!String.IsNullOrEmpty(path))
+			{
+				wallpaper = path;
+				logger.Info($"Saved wallpaper image: {wallpaper}.");
+				nativeMethods.RemoveWallpaper();
+				logger.Info("Removed current wallpaper.");
+			}
+		}
+
+		private void PreventSleepMode()
+		{
+			nativeMethods.DisableSleep();
+			logger.Info("Disabled sleep mode and display timeout.");
+		}
+
+		private void ResetWorkingArea()
+		{
+			var identifier = GetIdentifierForPrimaryDisplay();
+
+			if (originalWorkingArea != null)
+			{
+				nativeMethods.SetWorkingArea(originalWorkingArea);
+				LogWorkingArea($"Restored original working area for {identifier}", originalWorkingArea);
+			}
+			else
+			{
+				logger.Warn($"Could not restore original working area for {identifier}!");
+			}
+		}
+
+		private void ResetWallpaper()
+		{
+			if (!String.IsNullOrEmpty(wallpaper))
+			{
+				nativeMethods.SetWallpaper(wallpaper);
+				logger.Info($"Restored wallpaper image: {wallpaper}.");
+			}
+		}
+
+		private string GetIdentifierForPrimaryDisplay()
+		{
+			var display = Screen.PrimaryScreen.DeviceName?.Replace(@"\\.\", string.Empty);
+
+			return $"{display} ({Screen.PrimaryScreen.Bounds.Width}x{Screen.PrimaryScreen.Bounds.Height})";
+		}
+
+		private void LogWorkingArea(string message, IBounds area)
+		{
+			logger.Info($"{message}: Left = {area.Left}, Top = {area.Top}, Right = {area.Right}, Bottom = {area.Bottom}.");
+		}
+	}
+}

SafeExamBrowser.Monitoring/SafeExamBrowser.Monitoring.csproj

@@ -50,7 +50,9 @@
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Core" />
+    <Reference Include="System.Drawing" />
     <Reference Include="System.Management" />
+    <Reference Include="System.Windows.Forms" />
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="Microsoft.CSharp" />
@@ -60,10 +62,13 @@
     <Reference Include="WindowsBase" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Display\Bounds.cs" />
+    <Compile Include="Display\DisplayMonitor.cs" />
     <Compile Include="Keyboard\KeyboardInterceptor.cs" />
     <Compile Include="Mouse\MouseInterceptor.cs" />
     <Compile Include="Processes\ProcessMonitor.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Windows\Window.cs" />
     <Compile Include="Windows\WindowMonitor.cs" />
   </ItemGroup>
   <ItemGroup>

SafeExamBrowser.Monitoring/Windows/Window.cs

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2017 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System;
+
+namespace SafeExamBrowser.Monitoring.Windows
+{
+	internal struct Window
+	{
+		internal IntPtr Handle { get; set; }
+		internal string Title { get; set; }
+	}
+}

SafeExamBrowser.Monitoring/Windows/WindowMonitor.cs

@@ -117,11 +117,5 @@ namespace SafeExamBrowser.Monitoring.Windows
 		{
 			WindowChanged?.Invoke(window);
 		}
-
-		private struct Window
-		{
-			internal IntPtr Handle { get; set; }
-			internal string Title { get; set; }
-		}
 	}
 }

SafeExamBrowser.UserInterface/Taskbar.xaml.cs

@@ -10,14 +10,19 @@ using System.Windows;
 using System.Windows.Input;
 using System.Windows.Interop;
 using System.Windows.Media;
+using SafeExamBrowser.Contracts.Logging;
 using SafeExamBrowser.Contracts.UserInterface;
 
 namespace SafeExamBrowser.UserInterface
 {
 	public partial class Taskbar : Window, ITaskbar
 	{
-		public Taskbar()
+		private ILogger logger;
+
+		public Taskbar(ILogger logger)
 		{
+			this.logger = logger;
+
 			InitializeComponent();
 
 			Loaded += (o, args) => InitializeBounds();
@@ -41,28 +46,13 @@ namespace SafeExamBrowser.UserInterface
 
 		public int GetAbsoluteHeight()
 		{
-			// WPF works with device-independent pixels. The following code is required
-			// to get the real height of the taskbar (in absolute, device-specific pixels).
-			// Source: https://stackoverflow.com/questions/3286175/how-do-i-convert-a-wpf-size-to-physical-pixels
-
 			return Dispatcher.Invoke(() =>
 			{
-				Matrix transformToDevice;
-				var source = PresentationSource.FromVisual(this);
+				var height = (int) TransformToPhysical(Width, Height).Y;
 
-				if (source != null)
-				{
-					transformToDevice = source.CompositionTarget.TransformToDevice;
-				}
-				else
-				{
-					using (var newSource = new HwndSource(new HwndSourceParameters()))
-					{
-						transformToDevice = newSource.CompositionTarget.TransformToDevice;
-					}
-				}
+				logger.Info($"Calculated absolute taskbar height is {height}px.");
 
-				return (int)transformToDevice.Transform((Vector)new Size(Width, Height)).Y;
+				return height;
 			});
 		}
 
@@ -73,6 +63,11 @@ namespace SafeExamBrowser.UserInterface
 				Width = SystemParameters.WorkArea.Right;
 				Left = SystemParameters.WorkArea.Right - Width;
 				Top = SystemParameters.WorkArea.Bottom;
+
+				var position = TransformToPhysical(Left, Top);
+				var size = TransformToPhysical(Width, Height);
+
+				logger.Info($"Set taskbar bounds to {Width}x{Height} at ({Left}/{Top}), in physical pixels: {size.X}x{size.Y} at ({position.X}/{position.Y}).");
 			});
 		}
 
@@ -106,5 +101,29 @@ namespace SafeExamBrowser.UserInterface
 				}
 			}
 		}
+
+		private Vector TransformToPhysical(double x, double y)
+		{
+			// WPF works with device-independent pixels. The following code is required
+			// to transform those values to their absolute, device-specific pixel value.
+			// Source: https://stackoverflow.com/questions/3286175/how-do-i-convert-a-wpf-size-to-physical-pixels
+
+			Matrix transformToDevice;
+			var source = PresentationSource.FromVisual(this);
+
+			if (source != null)
+			{
+				transformToDevice = source.CompositionTarget.TransformToDevice;
+			}
+			else
+			{
+				using (var newSource = new HwndSource(new HwndSourceParameters()))
+				{
+					transformToDevice = newSource.CompositionTarget.TransformToDevice;
+				}
+			}
+
+			return transformToDevice.Transform(new Vector(x, y));
+		}
 	}
 }

SafeExamBrowser.WindowsApi/Constants/SPI.cs

@@ -14,12 +14,11 @@ namespace SafeExamBrowser.WindowsApi.Constants
 	internal enum SPI : uint
 	{
 		/// <summary>
-		/// Sets the size of the work area. The work area is the portion of the screen not obscured by the system taskbar
-		/// or by application desktop toolbars. The pvParam parameter is a pointer to a RECT structure that specifies the
-		/// new work area rectangle, expressed in virtual screen coordinates. In a system with multiple display monitors,
-		/// the function sets the work area of the monitor that contains the specified rectangle.
+		/// Retrieves the full path of the bitmap file for the desktop wallpaper. The pvParam parameter must point to a buffer
+		/// that receives a null-terminated path string. Set the uiParam parameter to the size, in characters, of the pvParam buffer.
+		/// The returned string will not exceed MAX_PATH characters. If there is no desktop wallpaper, the returned string is empty.
 		/// </summary>
-		SETWORKAREA = 0x002F,
+		GETDESKWALLPAPER = 0x73,
 
 		/// <summary>
 		/// Retrieves the size of the work area on the primary display monitor. The work area is the portion of the screen
@@ -27,6 +26,21 @@ namespace SafeExamBrowser.WindowsApi.Constants
 		/// RECT structure that receives the coordinates of the work area, expressed in virtual screen coordinates. To get
 		/// the work area of a monitor other than the primary display monitor, call the GetMonitorInfo function.
 		/// </summary>
-		GETWORKAREA = 0x0030,
+		GETWORKAREA = 0x30,
+
+		/// <summary>
+		/// Sets the desktop wallpaper. The value of the pvParam parameter determines the new wallpaper. To specify a wallpaper bitmap,
+		/// set pvParam to point to a null-terminated string containing the name of a bitmap file. Setting pvParam to "" removes the
+		/// wallpaper. Setting pvParam to SETWALLPAPER_DEFAULT or null reverts to the default wallpaper.
+		/// </summary>
+		SETDESKWALLPAPER = 0x14,
+
+		/// <summary>
+		/// Sets the size of the work area. The work area is the portion of the screen not obscured by the system taskbar
+		/// or by application desktop toolbars. The pvParam parameter is a pointer to a RECT structure that specifies the
+		/// new work area rectangle, expressed in virtual screen coordinates. In a system with multiple display monitors,
+		/// the function sets the work area of the monitor that contains the specified rectangle.
+		/// </summary>
+		SETWORKAREA = 0x2F,
 	}
 }

SafeExamBrowser.WindowsApi/Kernel32.cs

@@ -8,6 +8,7 @@
 
 using System;
 using System.Runtime.InteropServices;
+using SafeExamBrowser.WindowsApi.Types;
 
 namespace SafeExamBrowser.WindowsApi
 {
@@ -16,7 +17,10 @@ namespace SafeExamBrowser.WindowsApi
 	/// </summary>
 	internal class Kernel32
 	{
-		[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
-		public static extern IntPtr GetModuleHandle(string lpModuleName);
+		[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
+		internal static extern IntPtr GetModuleHandle(string lpModuleName);
+
+		[DllImport("kernel32.dll", SetLastError = true)]
+		internal static extern EXECUTION_STATE SetThreadExecutionState(EXECUTION_STATE esFlags);
 	}
 }

SafeExamBrowser.WindowsApi/NativeMethods.cs

@@ -94,6 +94,11 @@ namespace SafeExamBrowser.WindowsApi
 			EventDelegates.TryRemove(handle, out EventProc d);
 		}
 
+		public void DisableSleep()
+		{
+			Kernel32.SetThreadExecutionState(EXECUTION_STATE.CONTINUOUS | EXECUTION_STATE.DISPLAY_REQUIRED | EXECUTION_STATE.SYSTEM_REQUIRED);
+		}
+
 		public void EmptyClipboard()
 		{
 			var success = true;
@@ -149,6 +154,22 @@ namespace SafeExamBrowser.WindowsApi
 			return processId;
 		}
 
+		public string GetWallpaperPath()
+		{
+			const int MAX_PATH = 260;
+			var buffer = new String('\0', MAX_PATH);
+			var success = User32.SystemParametersInfo(SPI.GETDESKWALLPAPER, buffer.Length, buffer, 0);
+
+			if (!success)
+			{
+				throw new Win32Exception(Marshal.GetLastWin32Error());
+			}
+
+			var path = buffer.Substring(0, buffer.IndexOf('\0'));
+
+			return path;
+		}
+
 		public string GetWindowTitle(IntPtr window)
 		{
 			var length = User32.GetWindowTextLength(window);
@@ -256,6 +277,11 @@ namespace SafeExamBrowser.WindowsApi
 			return handle;
 		}
 
+		public void RemoveWallpaper()
+		{
+			SetWallpaper(string.Empty);
+		}
+
 		public void RestoreWindow(IntPtr window)
 		{
 			User32.ShowWindow(window, (int)ShowWindowCommand.Restore);
@@ -266,6 +292,16 @@ namespace SafeExamBrowser.WindowsApi
 			User32.SendMessage(window, Constant.WM_SYSCOMMAND, (IntPtr) SystemCommand.CLOSE, IntPtr.Zero);
 		}
 
+		public void SetWallpaper(string filePath)
+		{
+			var success = User32.SystemParametersInfo(SPI.SETDESKWALLPAPER, 0, filePath, SPIF.UPDATEANDCHANGE);
+
+			if (!success)
+			{
+				throw new Win32Exception(Marshal.GetLastWin32Error());
+			}
+		}
+
 		public void SetWorkingArea(IBounds bounds)
 		{
 			var workingArea = new RECT { Left = bounds.Left, Top = bounds.Top, Right = bounds.Right, Bottom = bounds.Bottom };

SafeExamBrowser.WindowsApi/SafeExamBrowser.WindowsApi.csproj

@@ -62,6 +62,7 @@
     <Compile Include="Constants\HookType.cs" />
     <Compile Include="Monitoring\MouseHook.cs" />
     <Compile Include="Types\Bounds.cs" />
+    <Compile Include="Types\EXECUTION_STATE.cs" />
     <Compile Include="Types\KBDLLHOOKSTRUCT.cs" />
     <Compile Include="Types\KBDLLHOOKSTRUCTFlags.cs" />
     <Compile Include="Constants\ShowWindowCommand.cs" />

SafeExamBrowser.WindowsApi/Types/EXECUTION_STATE.cs

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2017 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System;
+
+namespace SafeExamBrowser.WindowsApi.Types
+{
+	/// <remarks>
+	/// See http://www.pinvoke.net/default.aspx/kernel32/SetThreadExecutionState.html.
+	/// See https://msdn.microsoft.com/en-us/library/aa373208(v=vs.85).aspx.
+	/// </remarks>
+	[Flags]
+	public enum EXECUTION_STATE : uint
+	{
+		AWAYMODE_REQUIRED = 0x00000040,
+		CONTINUOUS = 0x80000000,
+		DISPLAY_REQUIRED = 0x00000002,
+		SYSTEM_REQUIRED = 0x00000001
+	}
+}

SafeExamBrowser.WindowsApi/Types/RECT.cs

@@ -11,9 +11,9 @@ using SafeExamBrowser.Contracts.WindowsApi;
 
 namespace SafeExamBrowser.WindowsApi.Types
 {
-	/// <summary>
+	/// <remarks>
 	/// See https://msdn.microsoft.com/en-us/library/windows/desktop/dd162897(v=vs.85).aspx.
-	/// </summary>
+	/// </remarks>
 	[StructLayout(LayoutKind.Sequential)]
 	internal struct RECT
 	{

SafeExamBrowser.WindowsApi/User32.cs

@@ -38,10 +38,10 @@ namespace SafeExamBrowser.WindowsApi
 		[return: MarshalAs(UnmanagedType.Bool)]
 		internal static extern bool EnumWindows(EnumWindowsDelegate enumProc, IntPtr lParam);
 
-		[DllImport("user32.dll", SetLastError = true)]
+		[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
 		internal static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
 
-		[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
+		[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
 		internal static extern int GetWindowText(IntPtr hWnd, StringBuilder strText, int maxCount);
 
 		[DllImport("user32.dll", SetLastError = true)]
@@ -79,6 +79,10 @@ namespace SafeExamBrowser.WindowsApi
 		[return: MarshalAs(UnmanagedType.Bool)]
 		internal static extern bool SystemParametersInfo(SPI uiAction, uint uiParam, ref RECT pvParam, SPIF fWinIni);
 
+		[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
+		[return: MarshalAs(UnmanagedType.Bool)]
+		internal static extern bool SystemParametersInfo(SPI uiAction, int uiParam, string pvParam, SPIF fWinIni);
+
 		[DllImport("user32.dll", SetLastError = true)]
 		internal static extern bool UnhookWinEvent(IntPtr hWinEventHook);
 

SafeExamBrowser/CompositionRoot.cs

@@ -21,6 +21,7 @@ using SafeExamBrowser.Core.Behaviour;
 using SafeExamBrowser.Core.Behaviour.Operations;
 using SafeExamBrowser.Core.I18n;
 using SafeExamBrowser.Core.Logging;
+using SafeExamBrowser.Monitoring.Display;
 using SafeExamBrowser.Monitoring.Keyboard;
 using SafeExamBrowser.Monitoring.Mouse;
 using SafeExamBrowser.Monitoring.Processes;
@@ -34,6 +35,7 @@ namespace SafeExamBrowser
 	{
 		private IApplicationController browserController;
 		private IApplicationInfo browserInfo;
+		private IDisplayMonitor displayMonitor;
 		private IKeyboardInterceptor keyboardInterceptor;
 		private ILogger logger;
 		private ILogContentFormatter logFormatter;
@@ -46,7 +48,6 @@ namespace SafeExamBrowser
 		private ITextResource textResource;
 		private IUserInterfaceFactory uiFactory;
 		private IWindowMonitor windowMonitor;
-		private IWorkingArea workingArea;
 
 		public IShutdownController ShutdownController { get; private set; }
 		public IStartupController StartupController { get; private set; }
@@ -59,22 +60,22 @@ namespace SafeExamBrowser
 			logger = new Logger();
 			logFormatter = new DefaultLogFormatter();
 			nativeMethods = new NativeMethods();
-			settings = new SettingsImpl();
-			Taskbar = new Taskbar();
+			settings = new Settings();
 			textResource = new XmlTextResource();
 			uiFactory = new UserInterfaceFactory();
 
 			logger.Subscribe(new LogFileWriter(logFormatter, settings));
 
 			text = new Text(textResource);
+			Taskbar = new Taskbar(new ModuleLogger(logger, typeof(Taskbar)));
 			browserController = new BrowserApplicationController(settings, text, uiFactory);
+			displayMonitor = new DisplayMonitor(new ModuleLogger(logger, typeof(DisplayMonitor)), nativeMethods);
 			keyboardInterceptor = new KeyboardInterceptor(settings.Keyboard, new ModuleLogger(logger, typeof(KeyboardInterceptor)));
 			mouseInterceptor = new MouseInterceptor(new ModuleLogger(logger, typeof(MouseInterceptor)), settings.Mouse);
 			processMonitor = new ProcessMonitor(new ModuleLogger(logger, typeof(ProcessMonitor)), nativeMethods);
 			windowMonitor = new WindowMonitor(new ModuleLogger(logger, typeof(WindowMonitor)), nativeMethods);
-			workingArea = new WorkingArea(new ModuleLogger(logger, typeof(WorkingArea)), nativeMethods);
 
-			runtimeController = new RuntimeController(new ModuleLogger(logger, typeof(RuntimeController)), processMonitor, Taskbar, windowMonitor, workingArea);
+			runtimeController = new RuntimeController(displayMonitor, new ModuleLogger(logger, typeof(RuntimeController)), processMonitor, Taskbar, windowMonitor);
 			ShutdownController = new ShutdownController(logger, settings, text, uiFactory);
 			StartupController = new StartupController(logger, settings, text, uiFactory);
 
@@ -82,7 +83,7 @@ namespace SafeExamBrowser
 			StartupOperations.Enqueue(new KeyboardInterceptorOperation(keyboardInterceptor, logger, nativeMethods));
 			StartupOperations.Enqueue(new WindowMonitorOperation(logger, windowMonitor));
 			StartupOperations.Enqueue(new ProcessMonitorOperation(logger, processMonitor));
-			StartupOperations.Enqueue(new WorkingAreaOperation(logger, Taskbar, workingArea));
+			StartupOperations.Enqueue(new DisplayMonitorOperation(displayMonitor, logger, Taskbar));
 			StartupOperations.Enqueue(new TaskbarOperation(logger, logFormatter, settings, Taskbar, text, uiFactory));
 			StartupOperations.Enqueue(new BrowserOperation(browserController, browserInfo, logger, Taskbar, uiFactory));
 			StartupOperations.Enqueue(new RuntimeControllerOperation(runtimeController, logger));