iris: separate layout allocation from lengths

core/src/widget/mod.rs

@@ -1,4 +1,4 @@
-use crate::{Axis, Len, Painter, Size};
+use crate::{Axis, LayoutLen, Painter, Size};
 use std::any::Any;
 
 mod data;
@@ -28,7 +28,7 @@ pub enum ChildOrder {
 pub trait Widget: Any {
     fn draw(&mut self, painter: &mut Painter);
 
-    fn size_hint(&self, _axis: Axis) -> Option<Len> {
+    fn size_hint(&self, _axis: Axis) -> Option<LayoutLen> {
         None
     }
 
@@ -63,8 +63,8 @@ impl Widget for () {
         true
     }
 
-    fn size_hint(&self, _axis: Axis) -> Option<Len> {
-        Some(Len::ZERO)
+    fn size_hint(&self, _axis: Axis) -> Option<LayoutLen> {
+        Some(LayoutLen::ZERO)
     }
 }