implementing Fixed constraint

crates/tek_core/src/engine.rs

@@ -385,6 +385,26 @@ impl<T> Align<T> {
     }
 }
 
+/// Enforce fixed size of drawing area
+pub enum Fixed<U: Number, T> {
+    /// Enforce fixed width
+    W(U, T),
+    /// Enforce fixed height
+    H(U, T),
+    /// Enforce fixed width and height
+    WH(U, U, T),
+}
+
+impl<N: Number, T> Fixed<N, T> {
+    pub fn inner (&self) -> &T {
+        match self {
+            Self::W(_, inner) => inner,
+            Self::H(_, inner) => inner,
+            Self::WH(_, _, inner) => inner,
+        }
+    }
+}
+
 /// Enforce minimum size of drawing area
 pub enum Min<U: Number, T> {
     /// Enforce minimum width