Input fields and refactors required to support them

Voile/Source/Rect.cs

@@ -3,23 +3,61 @@ namespace Voile;
 /// <summary>
 /// Represents a rectangle. Used to determine widget confines for UI layout.
 /// </summary>
-public record Rect(float Width = 0.0f, float Height = 0.0f)
+public class Rect(float width = 0.0f, float height = 0.0f)
 {
-    public float Width { get; set; } = Width;
-    public float Height { get; set; } = Height;
+    public float Width { get; set; } = width;
+    public float Height { get; set; } = height;
     public static Rect Zero => new Rect(0.0f, 0.0f);
     public float Area => Width * Height;
 
-    public int CompareTo(Rect? other)
-    {
-        if (other is null) return 1;
-        return Area.CompareTo(other.Area);
-    }
+    public int CompareTo(Rect other) => Area.CompareTo(other.Area);
 
     public static bool operator >(Rect left, Rect right) => left.CompareTo(right) > 0;
     public static bool operator <(Rect left, Rect right) => left.CompareTo(right) < 0;
     public static bool operator >=(Rect left, Rect right) => left.CompareTo(right) >= 0;
     public static bool operator <=(Rect left, Rect right) => left.CompareTo(right) <= 0;
+
+    /// <summary>
+    /// Returns the rectangle with the smallest width.
+    /// </summary>
+    /// <param name="a"></param>
+    /// <param name="b"></param>
+    /// <returns></returns>
+    public static Rect MinWidth(Rect a, Rect b)
+    {
+        if (a < b)
+        {
+            return a;
+        }
+        else if (a > b)
+        {
+            return b;
+        }
+
+        return a;
+    }
+
+    public static Rect MaxWidth(Rect a, Rect b)
+    {
+        if (a > b)
+        {
+            return a;
+        }
+
+        if (a < b)
+        {
+            return b;
+        }
+
+        return a;
+    }
+
+    public static Rect operator +(Rect left, Rect right)
+    {
+        var width = left.Width + right.Width;
+        var height = left.Height + right.Height;
+        return new(width, height);
+    }
 }
 
 /// <summary>
@@ -32,6 +70,8 @@ public struct Size : IEquatable<Size>
     public float Top;
     public float Bottom;
 
+    public static Size Zero => new Size(0.0f);
+
     public Size(float uniform)
     {
         Left = Right = Top = Bottom = uniform;
@@ -51,8 +91,6 @@ public struct Size : IEquatable<Size>
         Bottom = bottom;
     }
 
-    public static Size Zero => new Size(0);
-
     public static Rect operator +(Size margin, Rect rect) =>
         new Rect(rect.Width + margin.Left + margin.Right,
                  rect.Height + margin.Top + margin.Bottom);