Some changes to the UI elements.

Quik/Controls/CommonEnums.cs

@@ -0,0 +1,56 @@
+
+using System;
+
+namespace Quik.Controls
+{
+    public enum Dock
+    {
+        None,
+        Top,
+        Left,
+        Bottom,
+        Right,
+        Center
+    }
+
+    [Flags]
+    public enum Anchor
+    {
+        None = 0,
+        Top = 1 << 0,
+        Left = 1 << 1,
+        Bottom = 1 << 2,
+        Right = 1 << 3,
+        All = Top | Left | Bottom | Right
+    }
+
+    public enum Direction
+    {
+        Vertical,
+        Horizontal
+    }
+
+    public enum TextAlignment
+    {
+        Left,
+        Center,
+        Right,
+        Justify,
+    }
+
+    public enum VerticalAlignment
+    {
+        Top,
+        Center,
+        Bottom,
+        Justify,
+    }
+
+    public enum HorizontalAlignment
+    {
+        Left,
+        Center,
+        Right,
+        Justify
+    }
+}

Quik/Controls/ContainerControl.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace Quik.Controls
+{
+    public abstract class ContainerControl : Control, ICollection<Control>
+    {
+        private readonly List<Control> children = new List<Control>();
+
+        public int Count => children.Count;
+
+        public bool IsReadOnly => false;
+
+        public void Add(Control item)
+        {
+            children.Add(item);
+        }
+
+        public void Clear()
+        {
+            children.Clear();
+        }
+
+        public bool Contains(Control item)
+        {
+            return children.Contains(item);
+        }
+
+        public void CopyTo(Control[] array, int arrayIndex)
+        {
+            children.CopyTo(array, arrayIndex);
+        }
+
+        public IEnumerator<Control> GetEnumerator()
+        {
+            return children.GetEnumerator();
+        }
+
+        public bool Remove(Control item)
+        {
+            return children.Remove(item);
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return children.GetEnumerator();
+        }
+    }
+}

Quik/Controls/Control.cs

@@ -14,7 +14,10 @@ namespace Quik.Controls
             set => Style["padding"] = value;
         }
 
-        public bool IsVisualsValid { get; private set; }
+        public bool IsVisualsValid { get; private set; } = false;
+        public bool IsLayoutValid { get; private set; } = false;
+
+        protected bool IsLayoutSuspended { get; private set; } = false;
 
         public void InvalidateVisual()
         {
@@ -22,11 +25,39 @@ namespace Quik.Controls
             OnVisualsInvalidated(this, EventArgs.Empty);
         }
 
+        public void InvalidateLayout()
+        {
+            IsLayoutValid = false;
+            OnLayoutInvalidated(this, EventArgs.Empty);
+        }
+
+        public void SuspendLayout()
+        {
+            IsLayoutSuspended = true;
+        }
+
+        public void ResumeLayout()
+        {
+            IsLayoutSuspended = false;
+            InvalidateLayout();
+        }
+
         protected abstract void ValidateVisual(CommandList cmd);
+        protected abstract void ValidateLayout();
+
         protected override void PaintBegin(CommandList cmd)
         {
             base.PaintBegin(cmd);
 
+            if (!IsLayoutValid && !IsLayoutSuspended)
+            {
+                ValidateLayout();
+                OnLayoutValidated(this, EventArgs.Empty);
+                IsLayoutValid = true;
+
+                InvalidateVisual();
+            }
+
             if (!IsVisualsValid)
             {
                 ValidateVisual(drawCommands);
@@ -47,11 +78,13 @@ namespace Quik.Controls
         public event EventHandler StyleChanged;
         public event EventHandler VisualsInvalidated;
         public event EventHandler VisualsValidated;
+        public event EventHandler LayoutInvalidated;
+        public event EventHandler LayoutValidated;
 
         protected virtual void OnStyleChanged(object sender, EventArgs ea)
         {
             StyleChanged?.Invoke(sender, ea);
-            InvalidateVisual();
+            InvalidateLayout();
         }
 
         protected virtual void OnVisualsInvalidated(object sender, EventArgs ea)
@@ -63,5 +96,15 @@ namespace Quik.Controls
         {
             VisualsValidated?.Invoke(sender, ea);
         }
+
+        protected virtual void OnLayoutInvalidated(object sender, EventArgs ea)
+        {
+            LayoutInvalidated?.Invoke(sender, ea);
+        }
+
+        protected virtual void OnLayoutValidated(object sender, EventArgs ea)
+        {
+            LayoutValidated?.Invoke(sender, ea);
+        }
     }
 }

Quik/Controls/FlowBox.cs

@@ -0,0 +1,23 @@
+using System;
+using Quik.CommandMachine;
+
+namespace Quik.Controls
+{
+    public class FlowBox : ContainerControl
+    {
+        public Direction FlowDirection { get; set; }
+        public bool AllowWrap { get; set; }
+        public VerticalAlignment VerticalAlignment { get; set; }
+        public HorizontalAlignment HorizontalAlignment { get; set; }
+
+        protected override void ValidateLayout()
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override void ValidateVisual(CommandList cmd)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}

Quik/Controls/Label.cs

@@ -7,15 +7,26 @@ namespace Quik.Controls
     public class Label : Control
     {
         public string Text { get; set; }
-        public QFont TextFont { get; set; }
+        public QFont Font { get; set; }
         public float TextSize { get; set; }
 
+        public bool AutoSize { get; set; } = true;
+
+        protected override void ValidateLayout()
+        {
+            if (AutoSize)
+            {
+                QVec2 size = Typesetter.MeasureHorizontal(Text, TextSize, Font);
+                Size = size;
+            }
+        }
+
         protected override void ValidateVisual(CommandList cmd)
         {
             float padding = Padding;
             QVec2 origin = new QVec2(padding, padding);
 
-            cmd.TypesetHorizontalDirect(Text, origin, TextSize, TextFont);
+            cmd.TypesetHorizontalDirect(Text, origin, TextSize, Font);
         }
     }
 }

Quik/Controls/UIBase.cs

@@ -9,20 +9,32 @@ namespace Quik.Controls
     /// </summary>
     public abstract class UIBase
     {
+        private QVec2 size;
+
         public UIBase Parent { get; protected set; }
         public string Id { get; set; }
-        public QRectangle Bounds { get; set; }
-
-        public QVec2 Position
+        public QRectangle Bounds
         {
-            get => Bounds.Min;
-            set => Bounds = new QRectangle(Bounds.Max - Bounds.Min + value, value);
+            get => new QRectangle(Position + Size, Position);
+            set
+            {
+                Size = value.Size;
+                Position = value.Min;
+            }
         }
 
+        public QVec2 Position { get; set; }
+
         public QVec2 Size
         {
-            get => Bounds.Max - Bounds.Min;
-            set => Bounds = new QRectangle(value + Bounds.Min, Bounds.Min);
+            get => size;
+            set
+            {
+                QVec2 oldSize = size;
+                size = value;
+
+                OnResized(this, new ResizedEventArgs(size, oldSize));
+            }
         }
 
         public QRectangle AbsoluteBounds
@@ -40,7 +52,13 @@ namespace Quik.Controls
             }
         }
 
-        public void NotifyEvent(object sender, EventArgs args)
+        public QVec2 MaximumSize { get; set; } = new QVec2(-1, -1);
+        public QVec2 MinimumSize { get; set; } = new QVec2(-1, -1);
+
+        public bool IsMaximumSizeSet => MaximumSize != new QVec2(-1, -1);
+        public bool IsMinimumSizeSet => MinimumSize != new QVec2(-1, -1);
+
+        public virtual void NotifyEvent(object sender, EventArgs args)
         {
         }
 
@@ -61,5 +79,24 @@ namespace Quik.Controls
             PaintBegin(cmd);
             PaintEnd(cmd);
         }
+
+        public event EventHandler<ResizedEventArgs> Resized;
+
+        public virtual void OnResized(object sender, ResizedEventArgs ea)
+        {
+            Resized?.Invoke(sender, ea);
+        }
+    }
+
+    public class ResizedEventArgs : EventArgs
+    {
+        public QVec2 NewSize { get; }
+        public QVec2 OldSize { get; }
+
+        public ResizedEventArgs(QVec2 newSize, QVec2 oldSize)
+        {
+            NewSize = newSize;
+            OldSize = oldSize;
+        }
     }
 }

tests/QuikDemo/Program.cs

@@ -21,7 +21,7 @@ namespace QuikDemo
     public class EmptyView : View
     {
         private QFont font;
-        private readonly Label Label = new Label() { Text = "Hello world!", Size = new QVec2(256, 32), Position = new QVec2(300, 300) };
+        private readonly Label Label = new Label() { Text = "Hello world!", Position = new QVec2(300, 300) };
 
         protected override void PaintBegin(CommandList cmd)
         {
@@ -32,8 +32,8 @@ namespace QuikDemo
                 IFontDataBase db = FontDataBaseProvider.Instance;
                 font = new QFontFreeType(db.FontFileInfo(db.Sans).OpenRead());
 
-                Label.TextFont = font;
-                Label.TextSize = 16;
+                Label.Font = font;
+                Label.TextSize = 12;
                 Label.InvalidateVisual();
             }