Some additional work on dashboard architecture.

Dashboard.Common/Events/AnimationTickEventArgs.cs

@@ -0,0 +1,20 @@
+namespace Dashboard.Events
+{
+    public class AnimationTickEventArgs : UiEventArgs
+    {
+        /// <summary>
+        /// Animation delta time in seconds.
+        /// </summary>
+        public float Delta { get; }
+
+        public AnimationTickEventArgs(float delta) : base(UiEventType.AnimationTick)
+        {
+            Delta = delta;
+        }
+    }
+
+    public interface IAnimationTickEvent
+    {
+        event EventHandler<AnimationTickEventArgs> AnimationTimerEvent;
+    }
+}

Dashboard.Common/Events/MouseEvents.cs

@@ -0,0 +1,69 @@
+using System.Drawing;
+using System.Numerics;
+
+namespace Dashboard.Events
+{
+    [Flags]
+    public enum MouseButtons
+    {
+        M1 = 1 << 0,
+        M2 = 1 << 1,
+        M3 = 1 << 2,
+        M4 = 1 << 3,
+        M5 = 1 << 4,
+        M6 = 1 << 5,
+        M7 = 1 << 6,
+        M8 = 1 << 7,
+
+        Left = M1,
+        Right = M2,
+        Middle = M3,
+    }
+
+    public sealed class MouseMoveEventArgs : UiEventArgs
+    {
+        public Vector2 ClientPosition { get; }
+        public Vector2 Delta { get; }
+
+        public MouseMoveEventArgs(Vector2 clientPosition, Vector2 delta)
+            : base(UiEventType.MouseMove)
+        {
+            ClientPosition = clientPosition;
+            Delta = delta;
+        }
+    }
+
+    public sealed class MouseButtonEventArgs : UiEventArgs
+    {
+        public Vector2 ClientPosition { get; }
+        public MouseButtons Buttons { get; }
+
+        public MouseButtonEventArgs(Vector2 clientPosition, MouseButtons buttons, bool up)
+            : base(up ? UiEventType.MouseButtonUp : UiEventType.MouseButtonDown)
+        {
+            ClientPosition = clientPosition;
+            Buttons = buttons;
+        }
+    }
+
+    public sealed class MouseScrollEventArgs : UiEventArgs
+    {
+        public Vector2 ClientPosition { get; }
+        public Vector2 ScrollDelta { get; }
+
+        public MouseScrollEventArgs(Vector2 clientPosition, Vector2 scrollDelta)
+            : base(UiEventType.MouseScroll)
+        {
+            ClientPosition = clientPosition;
+            ScrollDelta = scrollDelta;
+        }
+    }
+
+    public interface IMouseEvents
+    {
+        event EventHandler<MouseMoveEventArgs> MouseMoved;
+        event EventHandler<MouseButtonEventArgs> MouseButtonDown;
+        event EventHandler<MouseButtonEventArgs> MouseButtonUp;
+        event EventHandler<MouseScrollEventArgs> MouseScroll;
+    }
+}

Dashboard.Common/Events/UiEventArgs.cs

@@ -0,0 +1,76 @@
+using System.Numerics;
+
+namespace Dashboard.Events
+{
+    public enum UiEventType
+    {
+        None,
+        AnimationTick,                  // Generic timer event.
+
+        // Text input related events.
+        KeyDown,                        // Keyboard key down.
+        KeyUp,                          // Keyboard key up.
+        TextInput,                      // Non-IME text event.
+        TextEdit,                       // IME text event.
+        TextCandidates,                 // IME text candidate list.
+        TextLanguage,                   // Keyboard language changed event.
+
+        // Mouse & touch related events
+        MouseButtonDown,                // Mouse button down.
+        MouseButtonUp,                  // Mouse button up.
+        MouseMove,                      // Mouse moved.
+        MouseScroll,                    // Mouse scrolled.
+
+        // Reserved event names
+        StylusEnter,                    // The stylus has entered the hover region.
+        StylusLeave,                    // The stylus has left the hover region.
+        StylusMove,                     // The stylus has moved.
+        StylusDown,                     // The stylus is touching.
+        StylusUp,                       // The stylus is no longer touching.
+        StylusButtonUp,                 // Stylus button up.
+        StylusButtonDown,               // Stylus button down.
+        StylusAxes,                     // Extra stylus axes data.
+
+        // Window & Control Events
+        ControlInvalidateVisual,        // Force rendering the control again.
+        ControlStateChanged,            // Control state changed.
+        ControlMoved,                   // Control moved.
+        ControlResized,                 // Control resized.
+        ControlEnter,                   // The pointing device entered the control.
+        ControlLeave,                   // The pointing device left the control.
+        ControlFocusGet,                // The control acquired focus.
+        ControlFocusLost,               // The control lost focus.
+        WindowClose,                    // The window closed.
+        
+        UserRangeStart = 1 << 12,
+    }
+
+    public class UiEventArgs : EventArgs
+    {
+        public UiEventType Type { get; }
+
+        public UiEventArgs(UiEventType type)
+        {
+            Type = type;
+        }
+
+        public static readonly UiEventArgs None = new UiEventArgs(UiEventType.None);
+    }
+
+    public class ControlMovedEventArgs : UiEventArgs
+    {
+        public Vector2 OldPosition { get; }
+        public Vector2 NewPosition { get; }
+
+        public ControlMovedEventArgs(Vector2 oldPosition, Vector2 newPosition) : base(UiEventType.ControlMoved)
+        {
+            OldPosition = oldPosition;
+            NewPosition = newPosition;
+        }
+    }
+
+    public class ControlResizedEventArgs
+    {
+        
+    }
+}

Dashboard.Common/Windowing/ICompositor.cs

@@ -0,0 +1,43 @@
+namespace Dashboard.Windowing
+{
+    /// <summary>
+    /// Interface for a class that composites multiple windows together.
+    /// </summary>
+    public interface ICompositor : IDisposable
+    {
+        void Composite(IPhysicalWindow window, IEnumerable<IVirtualWindow> windows);
+    }
+
+    /// <summary>
+    /// Interface for classes that implement a window manager.
+    /// </summary>
+    public interface IWindowManager : IEnumerable<IVirtualWindow>, IEventListener, IPaintable, IDisposable
+    {
+        /// <summary>
+        /// The physical window that this window manager is associated with.
+        /// </summary>
+        IPhysicalWindow PhysicalWindow { get; }
+
+        /// <summary>
+        /// The compositor that will composite all virtual windows.
+        /// </summary>
+        ICompositor Compositor { get; set; }
+
+        /// <summary>
+        /// The window that is currently focused.
+        /// </summary>
+        IVirtualWindow? FocusedWindow { get; }
+
+        /// <summary>
+        /// Create a virtual window.
+        /// </summary>
+        /// <returns>Virtual window handle.</returns>
+        IVirtualWindow CreateWindow();
+
+        /// <summary>
+        /// Focus a virtual window, if it is owned by this window manager.
+        /// </summary>
+        /// <param name="window">The window to focus.</param>
+        void Focus(IVirtualWindow window);
+    }
+}

Dashboard.Common/Windowing/IDeviceContext.cs

@@ -0,0 +1,20 @@
+using System.Drawing;
+
+namespace Dashboard.Windowing
+{
+    /// <summary>
+    /// Generic interface for the rendering system present in a <see cref="IPhysicalWindow"/>
+    /// </summary>
+    public interface IDeviceContext
+    {
+        /// <summary>
+        /// The swap group for this device context.
+        /// </summary>
+        ISwapGroup SwapGroup { get; }
+
+        /// <summary>
+        /// The size of the window framebuffer in pixels.
+        /// </summary>
+        Size FramebufferSize { get; }
+    }
+}

Dashboard.Common/Windowing/IEventListener.cs

@@ -0,0 +1,11 @@
+namespace Dashboard.Windowing
+{
+    public interface IEventListener
+    {
+        /// <summary>
+        /// Send an event to this windowing object.
+        /// </summary>
+        /// <param name="args">The event arguments sent.</param>
+        void SendEvent(EventArgs args);
+    }
+}

Dashboard.Common/Windowing/IPaintable.cs

@@ -0,0 +1,12 @@
+namespace Dashboard.Windowing
+{
+    public interface IPaintable
+    {
+        event EventHandler Painting;
+
+        /// <summary>
+        /// Paint this paintable object.
+        /// </summary>
+        void Paint();
+    }
+}

Dashboard.Common/Windowing/ISwapGroup.cs

@@ -0,0 +1,18 @@
+namespace Dashboard.Windowing
+{
+    /// <summary>
+    /// Interface that is used to swap the buffers of windows
+    /// </summary>
+    public interface ISwapGroup
+    {
+        /// <summary>
+        /// The swap interval for this swap group.
+        /// </summary>
+        public int SwapInterval { get; set; }
+
+        /// <summary>
+        /// Swap buffers.
+        /// </summary>
+        void Swap();
+    }
+}

Dashboard.Common/Windowing/IWindow.cs

@@ -1,11 +1,16 @@
 using System.Drawing;
+using Dashboard.Events;
 
-namespace Dashboard
+namespace Dashboard.Windowing
 {
     /// <summary>
     /// Base class of all Dashboard windows.
     /// </summary>
-    public interface IWindow : IDisposable
+    public interface IWindow :
+        IPaintable,
+        IDisposable,
+        IAnimationTickEvent,
+        IMouseEvents
     {
         /// <summary>
         /// Name of the window.
@@ -42,46 +47,8 @@ namespace Dashboard
     /// <summary>
     /// An object that represents a window in a virtual space, usually another window or a rendering system.
     /// </summary>
-    public interface IVirtualWindow : IWindow
+    public interface IVirtualWindow : IWindow, IEventListener
     {
-        /// <summary>
-        /// Send an event to this window.
-        /// </summary>
-        /// <param name="args">The event arguments</param>
-        /// TODO:
-        void SendEvent(EventArgs args);
-    }
-
-    /// <summary>
-    /// Generic interface for the rendering system present in a <see cref="IPhysicalWindow"/>
-    /// </summary>
-    public interface IDeviceContext
-    {
-        /// <summary>
-        /// The swap group for this device context.
-        /// </summary>
-        ISwapGroup SwapGroup { get; }
-
-        /// <summary>
-        /// The size of the window framebuffer in pixels.
-        /// </summary>
-        Size FramebufferSize { get; }
-    }
-
-    /// <summary>
-    /// Interface that is used to swap the buffers of
-    /// </summary>
-    public interface ISwapGroup
-    {
-        /// <summary>
-        /// The swap interval for this swap group.
-        /// </summary>
-        public int SwapInterval { get; set; }
-
-        /// <summary>
-        /// Swap buffers.
-        /// </summary>
-        void Swap();
     }
 
     /// <summary>
@@ -98,5 +65,10 @@ namespace Dashboard
         /// True if the window is double buffered.
         /// </summary>
         public bool DoubleBuffered { get; }
+
+        /// <summary>
+        /// The window manager for this physical window.
+        /// </summary>
+        public IWindowManager? WindowManager { get; set; }
     }
 }

Dashboard.Drawing/IDrawQueuePaintable.cs

@@ -0,0 +1,9 @@
+using Dashboard.Windowing;
+
+namespace Dashboard.Drawing
+{
+    public interface IDrawQueuePaintable : IPaintable
+    {
+        DrawQueue DrawQueue { get; }
+    }
+}

Dashboard.OpenGL/IGLContext.cs

@@ -1,4 +1,5 @@
 using System.Drawing;
+using Dashboard.Windowing;
 
 namespace Dashboard.OpenGL
 {

Dashboard.OpenTK/PAL2/EventConverter.cs

@@ -0,0 +1,18 @@
+using Dashboard.Events;
+using OpenTK.Platform;
+
+namespace Dashboard.OpenTK.PAL2
+{
+    public static class EventConverter
+    {
+        public static UiEventArgs? Convert(PlatformEventType type, EventArgs ea)
+        {
+            switch (type)
+            {
+                case PlatformEventType.KeyDown:
+                default:
+                    return null;
+            }
+        }
+    }
+}

Dashboard.OpenTK/PAL2/OpenGLDeviceContext.cs

@@ -1,6 +1,7 @@
 using System.Collections.Concurrent;
 using System.Drawing;
 using Dashboard.OpenGL;
+using Dashboard.Windowing;
 using OpenTK.Mathematics;
 using OpenTK.Platform;
 using TK = OpenTK.Platform.Toolkit;

Dashboard.OpenTK/PAL2/OpenTKEventExtensions.cs

@@ -0,0 +1,7 @@
+namespace Dashboard.OpenTK.PAL2
+{
+    public static class OpenTKEventExtensions
+    {
+        // public static EventArgs ToDashboardEvent(this EventArgs)
+    }
+}

Dashboard.OpenTK/PAL2/Pal2DashboardBackend.cs

@@ -0,0 +1,50 @@
+using Dashboard.Windowing;
+using OpenTK.Graphics;
+using OpenTK.Platform;
+using TK = OpenTK.Platform.Toolkit;
+
+namespace Dashboard.OpenTK.PAL2
+{
+    public class Pal2DashboardBackend : IDashboardBackend
+    {
+        public GraphicsApiHints GraphicsApiHints { get; set; } = new OpenGLGraphicsApiHints();
+        public bool OpenGLBindingsInitialized { get; set; } = false;
+
+        public IPhysicalWindow CreatePhysicalWindow()
+        {
+            PhysicalWindow window = new PhysicalWindow(GraphicsApiHints);
+
+            if (!OpenGLBindingsInitialized)
+            {
+                OpenGLBindingsInitialized = true;
+                GLLoader.LoadBindings(
+                    new Pal2BindingsContext(TK.OpenGL, 
+                    ((OpenGLDeviceContext)window.DeviceContext).ContextHandle));
+            }
+
+            return window;
+        }
+
+        public virtual IWindow CreateWindow()
+        {
+            return CreatePhysicalWindow();
+        }
+
+        public void Dispose()
+        {
+        }
+
+        public void Initialize()
+        {
+        }
+
+        public void Leave()
+        {
+        }
+
+        public void RunEvents(bool wait)
+        {
+            TK.Window.ProcessEvents(wait);
+        }
+    }
+}

Dashboard.OpenTK/PAL2/PhysicalWindow.cs

@@ -1,16 +1,24 @@
-using System.Drawing;
+using System.Collections.Concurrent;
+using System.Drawing;
+using Dashboard.Drawing;
+using Dashboard.Events;
+using Dashboard.Windowing;
 using OpenTK.Mathematics;
 using OpenTK.Platform;
+using MouseMoveEventArgs = Dashboard.Events.MouseMoveEventArgs;
 using TK = OpenTK.Platform.Toolkit;
 
 namespace Dashboard.OpenTK.PAL2
 {
-    public class PhysicalWindow : IPhysicalWindow
+    public class PhysicalWindow : IPhysicalWindow, IDrawQueuePaintable, IEventListener
     {
+        public DrawQueue DrawQueue { get; } = new DrawQueue();
         public WindowHandle WindowHandle { get; }
         public IDeviceContext DeviceContext { get; }
         public bool DoubleBuffered => true; // Always true for OpenTK windows.
 
+        public IWindowManager? WindowManager { get; set; }
+
         public string Title
         {
             get => TK.Window.GetTitle(WindowHandle);
@@ -37,22 +45,32 @@ namespace Dashboard.OpenTK.PAL2
             set => TK.Window.SetClientSize(WindowHandle, new Vector2i((int)value.Width, (int)value.Height));
         }
 
+        public event EventHandler? Painting;
+        public event EventHandler<AnimationTickEventArgs>? AnimationTimerEvent;
+        public event EventHandler<MouseMoveEventArgs>? MouseMoved;
+        public event EventHandler<MouseButtonEventArgs>? MouseButtonDown;
+        public event EventHandler<MouseButtonEventArgs>? MouseButtonUp;
+        public event EventHandler<MouseScrollEventArgs>? MouseScroll;
+
         public PhysicalWindow(WindowHandle window, IDeviceContext dc)
         {
             WindowHandle = window;
             DeviceContext = dc;
+            AddWindow(this);
         }
 
         public PhysicalWindow(WindowHandle window, OpenGLContextHandle context, ISwapGroup? swapGroup = null)
         {
             WindowHandle = window;
             DeviceContext = new OpenGLDeviceContext(window, context, swapGroup);
+            AddWindow(this);
         }
 
         public PhysicalWindow(GraphicsApiHints hints)
         {
             WindowHandle = TK.Window.Create(hints);
             DeviceContext = CreateDeviceContext(WindowHandle, hints);
+            AddWindow(this);
         }
 
         private static IDeviceContext CreateDeviceContext(WindowHandle window, GraphicsApiHints hints)
@@ -74,8 +92,73 @@ namespace Dashboard.OpenTK.PAL2
             if (_isDisposed) return;
             _isDisposed = true;
 
+            RemoveWindow(this);
+
             (DeviceContext as IDisposable)?.Dispose();
             TK.Window.Destroy(WindowHandle);
         }
+
+        protected virtual void OnPaint()
+        {
+            WindowManager?.Paint();
+            Painting?.Invoke(this, EventArgs.Empty);
+        }
+
+        public void Paint()
+        {
+            DrawQueue.Clear();
+            OnPaint();
+        }
+
+        protected virtual void OnAnimationTimerEvent(AnimationTickEventArgs ea) =>
+            AnimationTimerEvent?.Invoke(this, ea);
+
+        protected virtual void OnMouseMoved(MouseMoveEventArgs ea) => MouseMoved?.Invoke(this, ea);
+
+        protected virtual void OnMouseButtonDown(MouseButtonEventArgs ea) => MouseButtonDown?.Invoke(this, ea);
+
+        protected virtual void OnMouseButtonUp(MouseButtonEventArgs ea) => MouseButtonUp?.Invoke(this, ea);
+
+        protected virtual void OnMouseScroll(MouseScrollEventArgs ea) => MouseScroll?.Invoke(this, ea);
+
+        public void SendEvent(EventArgs args)
+        {
+        }
+
+        private static readonly ConcurrentDictionary<WindowHandle, PhysicalWindow> _windows =
+            new ConcurrentDictionary<WindowHandle, PhysicalWindow>();
+
+        static PhysicalWindow()
+        {
+            EventQueue.EventRaised += EventQueueOnEventRaised;
+        }
+
+        private static void AddWindow(PhysicalWindow window)
+        {
+            _windows.TryAdd(window.WindowHandle, window);
+        }
+
+        private static void RemoveWindow(PhysicalWindow window)
+        {
+            _windows.TryRemove(window.WindowHandle, out _);
+        }
+
+        private static void EventQueueOnEventRaised(PalHandle? handle, PlatformEventType type, EventArgs args)
+        {
+            if (handle is not WindowHandle windowHandle)
+                return;
+
+            if (!_windows.TryGetValue(windowHandle, out PhysicalWindow? window))
+                return;
+
+            switch (type)
+            {
+                case PlatformEventType.MouseMove:
+                case PlatformEventType.Scroll:
+                case PlatformEventType.MouseUp:
+                case PlatformEventType.MouseDown:
+                    break;
+            }
+        }
     }
 }

Dashboard/Application.cs

@@ -0,0 +1,130 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using Dashboard.Windowing;
+
+namespace Dashboard
+{
+    public class Application : IDisposable
+    {
+        public IDashboardBackend Backend { get; }
+        public IWindowFactory WindowFactory { get; set; }
+
+        public string Name { get; } = "Dashboard Application";
+
+        protected bool IsInitialized { get; private set; } = false;
+        protected bool IsDisposed { get; private set; } = false;
+
+        private readonly List<IPhysicalWindow> _physicalWindows = new List<IPhysicalWindow>();
+
+        public event EventHandler? PreInitializing;
+        public event EventHandler? Initializing;
+        public event EventHandler? PostInitializing;
+        public event EventHandler? Leaving;
+
+        public Application(IDashboardBackend backend)
+        {
+            Backend = backend;
+            WindowFactory = backend;
+        }
+
+        protected virtual void PreInitialize()
+        {
+            PreInitializing?.Invoke(this, EventArgs.Empty);
+        }
+
+        public virtual void Initialize()
+        {
+            Backend.Initialize();
+            Initializing?.Invoke(this, EventArgs.Empty);
+        }
+
+        protected virtual void PostInitialize()
+        {
+            PostInitializing?.Invoke(this, EventArgs.Empty);
+        }
+
+        private void InitializeInternal()
+        {
+            if (IsInitialized)
+                return;
+
+            IsInitialized = true;
+
+            PreInitialize();
+            Initialize();
+            PostInitialize();
+        }
+
+        public virtual void RunEvents(bool wait)
+        {
+            if (!IsInitialized)
+                throw new InvalidOperationException("The application is not initialized. Cannot run events at this time.");
+
+            Backend.RunEvents(wait);
+        }
+
+        public virtual void Leave()
+        {
+            Backend.Leave();
+        }
+
+        public void Run() => Run(true, CancellationToken.None);
+        public void Run(bool wait) => Run(wait, CancellationToken.None);
+        
+        public void Run(bool waitForEvents, CancellationToken token)
+        {
+            InitializeInternal();
+
+            while (!token.IsCancellationRequested)
+            {
+                RunEvents(waitForEvents);
+
+                foreach (IPhysicalWindow window in _physicalWindows)
+                {
+                    window.Paint();
+                }
+            }
+
+            Leave();
+        }
+
+        /// <inheritdoc cref="IWindowFactory.CreateWindow"/>
+        public IWindow CreateWindow()
+        {
+            IWindow window = WindowFactory.CreateWindow();
+
+            if (window is IPhysicalWindow physical)
+                _physicalWindows.Add(physical);
+
+            return window;
+        }
+
+        /// <inheritdoc cref="IWindowFactory.CreatePhysicalWindow"/>
+        public IPhysicalWindow CreatePhysicalWindow()
+        {
+            IPhysicalWindow window = WindowFactory.CreatePhysicalWindow();
+            _physicalWindows.Add(window);
+            return window;
+        } 
+
+        protected virtual void Dispose(bool disposing)
+        {
+        }
+
+        protected void InvokeDispose(bool disposing)
+        {
+            if (IsDisposed)
+                return;
+
+            IsDisposed = true;
+
+            Dispose(disposing);
+
+            if (disposing)
+                GC.SuppressFinalize(this);
+        }
+
+        public void Dispose() => InvokeDispose(true);
+    }
+}

Dashboard/Controls/ClassSet.cs

@@ -0,0 +1,77 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace Dashboard.Controls
+{
+    public enum ClassChangeType
+    {
+        Added,
+        Removed,
+    }
+
+    public record struct ClassChanged(object? Owner, string ClassName, ClassChangeType Type);
+
+    public class ClassSet : ICollection<string>
+    {
+        public int Count => _classes.Count;
+        public bool IsReadOnly => false;
+        public object? Owner { get; }
+        public event EventHandler<ClassChanged>? ClassChanged;
+
+        private readonly HashSet<string> _classes = new HashSet<string>();
+
+        public ClassSet(object? owner)
+        {
+            Owner = owner;
+        }
+
+        public IEnumerator<string> GetEnumerator() => _classes.GetEnumerator();
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+
+        public void Add(string item)
+        {
+            if (_classes.Add(item))
+            {
+                OnClassAdded(item);
+            }
+        }
+
+        public void Clear()
+        {
+            foreach (string @class in _classes)
+                OnClassRemoved(@class);
+
+            _classes.Clear();
+        }
+
+        public bool Contains(string item) => _classes.Contains(item);
+
+        public void CopyTo(string[] array, int arrayIndex) => _classes.CopyTo(array, arrayIndex);
+
+        public bool Remove(string item)
+        {
+            if (_classes.Remove(item))
+            {
+                OnClassRemoved(item);
+                return true;
+            }
+
+            return false;
+        }
+
+        private void OnClassAdded(string @class)
+        {
+            ClassChanged?.Invoke(this, new ClassChanged(Owner, @class, ClassChangeType.Added));
+        }
+
+        private void OnClassRemoved(string @class)
+        {
+            ClassChanged?.Invoke(this, new ClassChanged(Owner, @class, ClassChangeType.Removed));
+        }
+    }
+}

Dashboard/Controls/Control.cs

@@ -0,0 +1,68 @@
+using System;
+using Dashboard.Drawing;
+using Dashboard.Windowing;
+
+namespace Dashboard.Controls
+{
+    public class Control : IEventListener, IDrawQueuePaintable, IDisposable
+    {
+        public string? Id { get; set; }
+        public ClassSet Classes { get; }
+        public Form? Owner { get; protected set; } = null;
+        public Control? Parent { get; private set; } = null;
+        public bool Disposed { get; private set; }
+        public virtual DrawQueue DrawQueue => Owner?.DrawQueue ?? throw NoOwnerException;
+        public virtual Box2d ClientArea { get; set; }
+
+        public event EventHandler? Painting;
+        public event EventHandler? OwnerChanged;
+        public event EventHandler? ParentChanged;
+        public event EventHandler? Disposing;
+        public event EventHandler? Resized;
+
+        public Control()
+        {
+            Classes = new ClassSet(this);
+        }
+
+        public virtual void OnPaint()
+        {
+            Painting?.Invoke(this, EventArgs.Empty);
+        }
+
+        public void Paint()
+        {
+            OnPaint();
+        }
+
+        protected void InvokeDispose(bool disposing)
+        {
+            if (Disposed)
+                return;
+            Disposed = true;
+
+            Dispose(disposing);
+
+            if (disposing)
+                GC.SuppressFinalize(this);
+        }
+
+        protected virtual void Dispose(bool disposing)
+        {
+        }
+
+        public void Dispose() => InvokeDispose(true);
+
+        public void SendEvent(EventArgs args)
+        {
+            throw new NotImplementedException();
+        }
+
+        internal static void SetParent(Control parent, Control child)
+        {
+            child.Parent = parent;
+        }
+
+        protected static Exception NoOwnerException => new Exception("No form owns this control");
+    }
+}

Dashboard/Controls/Form.cs

@@ -0,0 +1,23 @@
+using Dashboard.Drawing;
+using Dashboard.Windowing;
+
+namespace Dashboard.Controls
+{
+    public class Form : Control
+    {
+        public IWindow Window { get; }
+        public override DrawQueue DrawQueue { get; }
+
+        public override Box2d ClientArea
+        {
+            get => new Box2d(0, 0, Window.ClientSize.Width, Window.ClientSize.Height);
+            set { }
+        }
+
+        public Form(IWindow window)
+        {
+            Window = window;
+            DrawQueue = (window as IDrawQueuePaintable)?.DrawQueue ?? new DrawQueue();
+        }
+    }
+}

Dashboard/Controls/Label.cs

@@ -0,0 +1,37 @@
+using System;
+using System.Drawing;
+using System.Numerics;
+using Dashboard.Drawing;
+
+namespace Dashboard.Controls
+{
+    public class Label : Control
+    {
+        public bool AutoSize { get; set; } = true;
+        public string Text { get; set; } = "";
+
+        public event EventHandler? TextChanged;
+
+        protected IBrush TextBrush => throw new NotImplementedException();
+        protected IFont Font => throw new NotImplementedException();
+
+        protected virtual void OnTextChanged(string oldValue, string newValue)
+        {
+            if (AutoSize)
+                CalculateSize();
+        }
+
+        protected void CalculateSize()
+        {
+            SizeF sz = Typesetter.MeasureString(Font, Text);
+            ClientArea = new Box2d(ClientArea.Min, ClientArea.Min + (Vector2)sz);
+        }
+
+
+        public override void OnPaint()
+        {
+            base.OnPaint();
+            DrawQueue.Text(new Vector3(ClientArea.Min, 0), TextBrush, Text, Font);
+        }
+    }
+}

Dashboard/IDashboardBackend.cs

@@ -0,0 +1,29 @@
+using System;
+using Dashboard.Windowing;
+
+namespace Dashboard
+{
+    public interface IWindowFactory
+    {
+        /// <summary>
+        /// Creates a window. It could be a virtual window, or a physical window.
+        /// </summary>
+        /// <returns>A window.</returns>
+        IWindow CreateWindow();
+
+        /// <summary>
+        /// Always creates a physical window.
+        /// </summary>
+        /// <returns>A physical window.</returns>
+        IPhysicalWindow CreatePhysicalWindow();
+    }
+
+    public interface IDashboardBackend : IDisposable, IWindowFactory
+    {
+        void Initialize();
+
+        void RunEvents(bool wait);
+
+        void Leave();
+    }
+}

tests/Dashboard.TestApplication/Program.cs

@@ -10,6 +10,7 @@ using OpenTK.Graphics.OpenGL;
 using OpenTK.Mathematics;
 using Box2d = Dashboard.Box2d;
 using TK = OpenTK.Platform.Toolkit;
+using Dashboard;
 
 TK.Init(new ToolkitOptions()
 {
@@ -21,8 +22,10 @@ TK.Init(new ToolkitOptions()
     }
 });
 
-PhysicalWindow window = new PhysicalWindow(new OpenGLGraphicsApiHints()
+Application app = new Application(new Pal2DashboardBackend() 
 { 
+    GraphicsApiHints = new OpenGLGraphicsApiHints()
+    {
         Version = new Version(3, 2),
         ForwardCompatibleFlag = true,
         DebugFlag = true,
@@ -38,67 +41,70 @@ PhysicalWindow window = new PhysicalWindow(new OpenGLGraphicsApiHints()
         Multisamples = 0,
 
         SupportTransparentFramebufferX11 = true,
+    }
 });
 
-window.Title = "DashTerm";
-TK.Window.SetMinClientSize(window.WindowHandle, 300, 200);
-TK.Window.SetClientSize(window.WindowHandle, new Vector2i(320, 240));
-TK.Window.SetBorderStyle(window.WindowHandle, WindowBorderStyle.ResizableBorder);
-// TK.Window.SetTransparencyMode(wnd, WindowTransparencyMode.TransparentFramebuffer, 0.1f);
-
-OpenGLDeviceContext context = (OpenGLDeviceContext)window.DeviceContext;
-
-context.MakeCurrent();
-context.SwapGroup.SwapInterval = 1;
-
-GLLoader.LoadBindings(new Pal2BindingsContext(TK.OpenGL, context.ContextHandle));
-
-DrawQueue queue = new DrawQueue();
+PhysicalWindow window;
 SolidBrush fg = new SolidBrush(Color.FromArgb(0, 0, 0, 0));
 SolidBrush bg = new SolidBrush(Color.Black);
-bool shouldExit = false;
-
-GLEngine engine = new GLEngine();
-engine.Initialize();
-
-ContextExecutor executor = engine.GetExecutor(context);
-DimUI dimUI = new DimUI(new DimUIConfig()
-{
-    Font = new NamedFont("Noto Sans", 9f),
-});
-
+CancellationTokenSource source = new CancellationTokenSource();
+GLEngine engine;
+ContextExecutor executor;
+DimUI dimUI;
 Vector2 mousePos = Vector2.Zero;
 Random r = new Random();
-EventQueue.EventRaised += (handle, type, eventArgs) =>
-{
+List<Vector3> points = new List<Vector3>();
+IFont font;
+StringBuilder builder = new StringBuilder();
+
+app.PostInitializing += (sender, ea) => {
+    window = (PhysicalWindow)app.CreatePhysicalWindow();
+
+    window.Title = "DashTerm";
+    TK.Window.SetMinClientSize(window.WindowHandle, 300, 200);
+    TK.Window.SetClientSize(window.WindowHandle, new Vector2i(320, 240));
+    TK.Window.SetBorderStyle(window.WindowHandle, WindowBorderStyle.ResizableBorder);
+    // TK.Window.SetTransparencyMode(wnd, WindowTransparencyMode.TransparentFramebuffer, 0.1f);
+
+    OpenGLDeviceContext context = (OpenGLDeviceContext)window.DeviceContext;
+
+    context.MakeCurrent();
+    context.SwapGroup.SwapInterval = 1;
+
+    engine = new GLEngine();
+    engine.Initialize();
+    
+    executor = engine.GetExecutor(context);
+
+    dimUI = new DimUI(new DimUIConfig()
+    {
+        Font = new NamedFont("Noto Sans", 9f),
+    });
+
+    EventQueue.EventRaised += (handle, type, eventArgs) =>
+    {
         if (handle != window.WindowHandle)
             return;
 
         switch (type)
         {
             case PlatformEventType.Close:
-            shouldExit = true;
+                source.Cancel();
                 break;
             case PlatformEventType.MouseMove:
                 mousePos = ((MouseMoveEventArgs)eventArgs).ClientPosition;
                 break;
         }
-};
+    };
 
-TK.Window.SetMode(window.WindowHandle, WindowMode.Normal);
+    TK.Window.SetMode(window.WindowHandle, WindowMode.Normal);
+    font = Typesetter.LoadFont("Nimbus Mono", 12f);
 
-List<Vector3> points = new List<Vector3>();
-
-IFont font = Typesetter.LoadFont("Nimbus Mono", 12f);
-StringBuilder builder = new StringBuilder();
-
-while (!shouldExit)
-{
-    TK.Window.ProcessEvents(true);
+    window.Painting += (sender, ea) => {
             TK.Window.GetFramebufferSize(context.WindowHandle, out Vector2i framebufferSize);
             executor.BeginFrame();
 
-    dimUI.Begin(new Box2d(0, 0, framebufferSize.X, framebufferSize.Y), queue);
+            dimUI.Begin(new Box2d(0, 0, framebufferSize.X, framebufferSize.Y), window.DrawQueue);
             dimUI.Text("Hello World!");
             dimUI.Button("Cancel"); dimUI.SameLine();
             dimUI.Button("OK");
@@ -161,9 +167,11 @@ while (!shouldExit)
             GL.BlendFunc(BlendingFactor.SrcAlpha, BlendingFactor.OneMinusSrcAlpha);
             GL.ColorMask(true, true, true, true);
 
-    executor.Draw(queue);
+            executor.Draw(window.DrawQueue);
             executor.EndFrame();
-    queue.Clear();
 
             context.SwapGroup.Swap();
-}
+    };
+};
+
+app.Run(true, source.Token);