WIP: UI input handling.

Voile/Source/UI/Widgets/Widget.cs

@@ -16,13 +16,19 @@ public abstract class Widget : IElement, IRenderableElement, IInputElement, IRes
 
     public Widget()
     {
+        MarkDirty();
+    }
 
+    public Widget(Rect size)
+    {
+        Size = size;
+        MarkDirty();
     }
 
     public Widget(Vector2 position)
     {
         Position = position;
-        Size = MinimumRect;
+        MarkDirty();
     }
 
     /// </inheritdoc>
@@ -36,11 +42,17 @@ public abstract class Widget : IElement, IRenderableElement, IInputElement, IRes
     /// <param name="renderer"></param>
     public abstract void Render(RenderSystem renderer, Style style);
 
+    public void Input(UIInputContext context)
+    {
+        if (context.Handled) return;
+        OnInput(context);
+    }
+
     /// <summary>
     /// Called when this widget receives input.
     /// </summary>
     /// <param name="action">An input action this widget received.</param>
-    public abstract void Input(IInputAction action);
+    protected abstract void OnInput(UIInputContext action);
 
     public void Update()
     {