Draft custom layout engine based on druid

core/src/length.rs

@@ -1,7 +1,17 @@
 /// The strategy used to fill space in a specific dimension.
-#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Hash)]
 pub enum Length {
     Fill,
     Shrink,
     Units(u16),
 }
+
+impl Length {
+    pub fn fill_factor(&self) -> u16 {
+        match self {
+            Length::Fill => 1,
+            Length::Shrink => 0,
+            Length::Units(_) => 0,
+        }
+    }
+}