Add ContainsPoint helper method to Widget.

Voile/Source/UI/Widgets/Widget.cs

@@ -61,5 +61,18 @@ public abstract class Widget : IElement, IRenderableElement, IInputElement, IRes
         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;
 }