Unify Containers and Widgets by creating a base UIElement, add more anchor types, make anchor calculations an extension of Anchor.

Voile/Source/UI/Anchor.cs

@@ -1,3 +1,5 @@
+using System.Numerics;
+
 namespace Voile.UI;
 
 public enum Anchor
@@ -5,11 +7,35 @@ public enum Anchor
     TopLeft,
     TopCenter,
     TopRight,
-    Left,
+    CenterLeft,
     Center,
-    Right,
+    CenterRight,
     BottomLeft,
     BottomCenter,
     BottomRight,
     Fill
+}
+
+
+public static class AnchorExtensions
+{
+    public static Vector2 Calculate(this Anchor anchor, Vector2 parentPosition, Rect parentRect, Rect elementRect)
+    {
+        var size = new Vector2(elementRect.Width, elementRect.Height);
+        var parentSize = new Vector2(parentRect.Width, parentRect.Height);
+
+        return anchor switch
+        {
+            Anchor.TopLeft => Vector2.Zero,
+            Anchor.TopCenter => new Vector2((parentSize.X - size.X) / 2, 0),
+            Anchor.TopRight => new Vector2(parentSize.X - size.X, 0),
+            Anchor.CenterLeft => new Vector2(0, (parentSize.Y - size.Y) / 2),
+            Anchor.Center => (parentSize - size) / 2,
+            Anchor.CenterRight => new Vector2(parentSize.X - size.X, (parentSize.Y - size.Y) / 2),
+            Anchor.BottomLeft => new Vector2(0, parentSize.Y - size.Y),
+            Anchor.BottomCenter => new Vector2((parentSize.X - size.X) / 2, parentSize.Y - size.Y),
+            Anchor.BottomRight => parentSize - size,
+            _ => Vector2.Zero
+        };
+    }
 }

Voile/Source/UI/Containers/Container.cs

@@ -7,46 +7,17 @@ namespace Voile.UI.Containers;
 /// <summary>
 /// A base class for all UI containers, used to position and rendering child <see cref="IElement">s.
 /// </summary>
-public abstract class Container : IElement, IParentableElement, IUpdatableElement, IResizeableElement, IRenderableElement, IAnchorableElement
+public abstract class Container : UIElement, IParentableElement
 {
     /// <inheritdoc />
     public IReadOnlyList<IElement> Children => _children;
-    /// <inheritdoc />
-    public Vector2 Position { get; set; }
-    /// <inheritdoc />
-    public Rect MinimumRect { get; set; } = Rect.Zero;
-    /// <inheritdoc />
-    public Rect Size
-    {
-        get => _size;
-        set
-        {
-            _size = value;
-
-            if (value.Width < MinimumRect.Width)
-            {
-                _size.Width = MinimumRect.Width;
-            }
-
-            if (value.Height < MinimumRect.Height)
-            {
-                _size.Height = MinimumRect.Height;
-            }
-
-            MarkDirty();
-        }
-    }
-    /// <inheritdoc />
-    public bool Visible { get; set; } = true;
-    /// <inheritdoc />
-    public bool Dirty => _isDirty;
 
     /// <summary>
     /// Specifies if this <see cref="Container"/>'s minimum size will be confined to contents.
     /// </summary>
     public bool ConfineToContents { get; set; } = false;
-     public Anchor Anchor { get; set; }
+
-    public Vector2 AnchorOffset { get; set; }
+    public override Rect MinimumSize => _minimumSize;
 
     public Container()
     {
@@ -55,28 +26,26 @@ public abstract class Container : IElement, IParentableElement, IUpdatableElemen
 
     public Container(Rect minimumSize)
     {
-        MinimumRect = minimumSize;
+        _minimumSize = minimumSize;
 
         MarkDirty();
     }
 
     public Container(Rect minimumSize, List<IElement> children)
     {
-        MinimumRect = minimumSize;
+        _minimumSize = minimumSize;
         _children = children;
 
         MarkDirty();
     }
 
-    public void Update()
+    protected override void OnUpdate()
     {
-        if (!_isDirty) return;
-        _isDirty = false;
-
-
         foreach (var child in _children)
         {
             if (child is not IUpdatableElement updatable) continue;
+
+            updatable.MarkDirty();
             updatable.Update();
 
             if (child is IAnchorableElement anchorable)
@@ -93,8 +62,6 @@ public abstract class Container : IElement, IParentableElement, IUpdatableElemen
         }
     }
 
-    public void MarkDirty() => _isDirty = true;
-
     /// <summary>
     /// Called when this <see cref="Container"/> has to rearrange its children.
     /// </summary>
@@ -127,14 +94,14 @@ public abstract class Container : IElement, IParentableElement, IUpdatableElemen
         float occupiedWidth = (maxX - minX) + padding * 2;
         float occupiedHeight = (maxY - minY) + padding * 2;
 
-        float finalWidth = MathF.Max(occupiedWidth, MinimumRect.Width);
+        float finalWidth = MathF.Max(occupiedWidth, _minimumSize.Width);
-        float finalHeight = MathF.Max(occupiedHeight, MinimumRect.Height);
+        float finalHeight = MathF.Max(occupiedHeight, _minimumSize.Height);
 
-        MinimumRect = new Rect(finalWidth, finalHeight);
+        Size = new Rect(finalWidth, finalHeight);
 
-        if (MinimumRect > _size)
+        if (_minimumSize > Size)
         {
-            _size = MinimumRect;
+            Size = _minimumSize;
         }
     }
 
@@ -154,7 +121,7 @@ public abstract class Container : IElement, IParentableElement, IUpdatableElemen
         Update();
     }
 
-    public void Render(RenderSystem renderer, Style style)
+    public override void Render(RenderSystem renderer, Style style)
     {
         foreach (var child in Children)
         {
@@ -163,45 +130,6 @@ public abstract class Container : IElement, IParentableElement, IUpdatableElemen
         }
     }
 
-    public void DrawSize(RenderSystem renderer)
-    {
-        renderer.SetTransform(Position, Vector2.Zero);
-        renderer.DrawRectangleOutline(new Vector2(Size.Width, Size.Height), Color.Red, 2.0f);
-    }
-
-    public void ApplyAnchor(Vector2 parentPosition, Rect parentRect)
-    {
-        var absoluteOffset = AnchorOffset * new Vector2(Size.Width, Size.Height);
-
-        switch (Anchor)
-        {
-            case Anchor.TopLeft:
-                Position = parentPosition - AnchorOffset;
-                break;
-            case Anchor.TopCenter:
-                var topCenterX = parentRect.Width / 2;
-                var topCenterY = parentPosition.Y;
-
-                Position = new Vector2(parentPosition.X + topCenterX, topCenterY) - absoluteOffset;
-                break;
-            case Anchor.TopRight:
-                Position = new Vector2(parentPosition.X + parentRect.Width, parentPosition.Y) - absoluteOffset;
-                break;
-
-            case Anchor.Fill:
-                Position = parentPosition;
-                Size = parentRect;
-                break;
-
-            default:
-                throw new NotImplementedException("This anchor type is not implemented!");
-        }
-
-        MarkDirty();
-        Update();
-    }
-
     private List<IElement> _children = new();
-    private bool _isDirty;
+    private Rect _minimumSize = Rect.Zero;
-    private Rect _size = Rect.Zero;
 }

Voile/Source/UI/Containers/FlexContainer.cs

@@ -148,7 +148,7 @@ public class FlexContainer : Container
     private Vector2 GetChildSize(IElement child)
     {
         if (child is IResizeableElement resizeable)
-            return new Vector2(resizeable.MinimumRect.Width, resizeable.MinimumRect.Height);
+            return new Vector2(resizeable.MinimumSize.Width, resizeable.MinimumSize.Height);
         return new Vector2(child.Size.Width, child.Size.Height);
     }
 

Voile/Source/UI/IElement.cs

@@ -39,7 +39,7 @@ public interface IResizeableElement
     /// <summary>
     /// Get a minimum rectangle size for this element.
     /// </summary>
-    public abstract Rect MinimumRect { get; }
+    public abstract Rect MinimumSize { get; }
 }
 
 public interface IUpdatableElement

Voile/Source/UI/UIElement.cs

@@ -0,0 +1,91 @@
+using System.Numerics;
+using Voile.Rendering;
+
+namespace Voile.UI;
+
+public abstract class UIElement : IElement, IRenderableElement, IResizeableElement, IUpdatableElement, IAnchorableElement
+{
+    public bool Visible { get; set; } = true;
+    public bool IgnoreInput { get; set; } = false;
+    public Vector2 Position { get; set; } = Vector2.Zero;
+    public Rect Size
+    {
+        get => _size;
+        set
+        {
+            _size = value;
+
+            if (value.Width < MinimumSize.Width)
+            {
+                _size.Width = MinimumSize.Width;
+            }
+
+            if (value.Height < MinimumSize.Height)
+            {
+                _size.Height = MinimumSize.Height;
+            }
+
+            MarkDirty();
+        }
+    }
+    public Vector2 AnchorOffset { get; set; } = Vector2.Zero;
+    public Anchor Anchor { get; set; } = Anchor.TopLeft;
+
+    public abstract Rect MinimumSize { get; }
+    public bool Dirty => _dirty;
+
+    public virtual void MarkDirty() => _dirty = true;
+
+    public void Update()
+    {
+        if (!_dirty) return;
+        _dirty = false;
+
+        if (Size == Rect.Zero)
+            Size = MinimumSize;
+
+        OnUpdate();
+
+        if (_parentRect != Rect.Zero)
+        {
+            ApplyAnchor(_parentPosition, _parentRect);
+        }
+    }
+
+    public abstract void Render(RenderSystem renderer, Style style);
+    protected abstract void OnUpdate();
+
+    public void DrawSize(RenderSystem renderer)
+    {
+        renderer.SetTransform(Position, Vector2.Zero);
+        renderer.DrawRectangleOutline(new Vector2(Size.Width, Size.Height), Color.Red, 2.0f);
+    }
+
+    /// <summary>
+    /// Determines if this <see cref="UIElement"/> contains a point within its confines.
+    /// </summary>
+    /// <param name="pointPosition">A global position of the point.</param>
+    /// <returns>True if the point is inside the widget; otherwise, false.</returns>
+    public bool ContainsPoint(Vector2 point)
+    {
+        return point.X >= Position.X && point.Y >= Position.Y &&
+               point.X <= Position.X + Size.Width &&
+               point.Y <= Position.Y + Size.Height;
+    }
+
+    /// <summary>
+    /// Applies this <see cref="UIElement"/> anchor.
+    /// </summary>
+    public virtual void ApplyAnchor(Vector2 parentPosition, Rect parentRect)
+    {
+        _parentPosition = parentPosition;
+        _parentRect = parentRect;
+        Position = Anchor.Calculate(parentPosition, parentRect, Size) + new Vector2(AnchorOffset.X, AnchorOffset.Y);
+    }
+
+    private bool _dirty = true;
+    private Rect _size = Rect.Zero;
+
+    private Vector2 _parentPosition = Vector2.Zero;
+    private Rect _parentRect = Rect.Zero;
+}

Voile/Source/UI/Widgets/Button.cs

@@ -18,7 +18,7 @@ public enum ButtonState
 public class Button : Widget
 {
     public string Label { get; set; } = "Button";
-    public override Rect MinimumRect => new Rect(Width: 128.0f, Height: 64.0f);
+    public override Rect MinimumSize => new Rect(Width: 128.0f, Height: 64.0f);
 
     public Button(string label, Action pressedAction)
     {
@@ -30,7 +30,7 @@ public class Button : Widget
     {
         // TODO: use a button color from style.
         renderer.SetTransform(Position, Vector2.Zero);
-        renderer.DrawRectangle(new Vector2(MinimumRect.Width, MinimumRect.Height), new Color(0.25f, 0.25f, 0.25f));
+        renderer.DrawRectangle(new Vector2(MinimumSize.Width, MinimumSize.Height), new Color(0.25f, 0.25f, 0.25f));
     }
 
     protected override void OnInput(UIInputContext action)
@@ -38,5 +38,10 @@ public class Button : Widget
 
     }
 
+    protected override void OnUpdate()
+    {
+        throw new NotImplementedException();
+    }
+
     private Action _pressedAction;
 }

Voile/Source/UI/Widgets/Label.cs

@@ -6,7 +6,7 @@ namespace Voile.UI.Widgets;
 
 public class Label : Widget
 {
-    public override Rect MinimumRect => throw new NotImplementedException();
+    public override Rect MinimumSize => throw new NotImplementedException();
 
     public string Text { get; set; } = "Hello World!";
 
@@ -34,5 +34,10 @@ public class Label : Widget
         renderer.DrawText(_fontOverride, Text, Color.White);
     }
 
+    protected override void OnUpdate()
+    {
+        throw new NotImplementedException();
+    }
+
     private ResourceRef<Font> _fontOverride = ResourceRef<Font>.Empty();
 }

Voile/Source/UI/Widgets/RectangleWidget.cs

@@ -6,11 +6,11 @@ namespace Voile.UI.Widgets;
 
 public class RectangleWidget : Widget
 {
-    public override Rect MinimumRect { get; }
+    public override Rect MinimumSize { get; }
     public Color Color { get; set; } = Color.White;
     public RectangleWidget(Rect minimumRect, Color color) : base()
     {
-        MinimumRect = minimumRect;
+        MinimumSize = minimumRect;
         Color = color;
 
         _defaultColor = color;
@@ -65,6 +65,11 @@ public class RectangleWidget : Widget
         }
     }
 
+    protected override void OnUpdate()
+    {
+
+    }
+
     private Color _defaultColor;
     private Color _hoverColor;
 

Voile/Source/UI/Widgets/Widget.cs

@@ -1,5 +1,4 @@
 using System.Numerics;
-using System.Xml.Serialization;
 using Voile.Input;
 using Voile.Rendering;
 
@@ -8,13 +7,8 @@ namespace Voile.UI.Widgets;
 /// <summary>
 /// A base class for all UI widgets.
 /// </summary>
-public abstract class Widget : IElement, IRenderableElement, IInputElement, IResizeableElement, IUpdatableElement, IAnchorableElement
+public abstract class Widget : UIElement, IInputElement
 {
-    public bool Visible { get; set; } = true;
-    public bool IgnoreInput { get; set; }
-    public Vector2 Position { get; set; } = Vector2.Zero;
-    public Rect Size { get; set; } = new();
-
     public Widget()
     {
         MarkDirty();
@@ -32,90 +26,18 @@ public abstract class Widget : IElement, IRenderableElement, IInputElement, IRes
         MarkDirty();
     }
 
-    /// </inheritdoc>
-    public abstract Rect MinimumRect { get; }
-
-    public bool Dirty => _isDirty;
-
-    public Anchor Anchor { get; set; }
-    public Vector2 AnchorOffset { get; set; }
-
-    public void ApplyAnchor(Vector2 parentPosition, Rect parentRect)
-    {
-        switch (Anchor)
-        {
-            case Anchor.TopLeft:
-                Position = parentPosition + AnchorOffset;
-                break;
-            case Anchor.TopCenter:
-                var topCenterX = parentRect.Width / 2;
-                var topCenterY = parentPosition.Y;
-
-                Position = new Vector2(parentPosition.X + topCenterX, topCenterY) + AnchorOffset;
-                break;
-            case Anchor.TopRight:
-                Position = new Vector2(parentPosition.X + parentRect.Width, parentPosition.Y);
-                break;
-
-            case Anchor.Fill:
-                Position = parentPosition;
-                Size = parentRect;
-                break;
-
-            default:
-                throw new NotImplementedException("This anchor type is not implemented!");
-        }
-    }
-
-    /// <summary>
-    /// Called when its time to draw this widget.
-    /// </summary>
-    /// <param name="renderer"></param>
-    public abstract void Render(RenderSystem renderer, Style style);
-
     public void Input(UIInputContext context)
     {
-        if (context.Handled) return;
+        if (context.Handled || IgnoreInput) return;
-        OnInput(context);
+        if (ContainsPoint(context.MousePosition))
+        {
+            OnInput(context);
+        }
     }
 
     /// <summary>
     /// Called when this widget receives input.
     /// </summary>
     /// <param name="action">An input action this widget received.</param>
-    protected abstract void OnInput(UIInputContext action);
+    protected abstract void OnInput(UIInputContext context);
-
-    public void Update()
-    {
-        if (!_isDirty) return;
-        _isDirty = false;
-
-        if (Size == Rect.Zero)
-        {
-            Size = MinimumRect;
-        }
-    }
-
-    public void MarkDirty() => _isDirty = true;
-
-    public void DrawSize(RenderSystem renderer)
-    {
-        renderer.SetTransform(Position, Vector2.Zero);
-        renderer.DrawRectangleOutline(new Vector2(Size.Width, Size.Height), Color.Red, 2.0f);
-    }
-
-    /// <summary>
-    /// Determines if this <see cref="Widget"/> contains a point within its confines.
-    /// </summary>
-    /// <param name="pointPosition">A global position of the point.</param>
-    /// <returns>True if the point is inside the widget; otherwise, false.</returns>
-    public bool ContainsPoint(Vector2 pointPosition)
-    {
-        return pointPosition.X >= Position.X &&
-               pointPosition.Y >= Position.Y &&
-               pointPosition.X <= Position.X + Size.Width &&
-               pointPosition.Y <= Position.Y + Size.Height;
-    }
-
-    private bool _isDirty = true;
 }