FlexibleDimension now implements Zero

CHANGELOG.md

@@ -45,6 +45,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Dynamic<Children>::wrap` has been renamed to `into_wrap` for consistency.
 - Cushy now has its own `KeyEvent` type, as winit's has private fields. This
   prevented simulating input in a `VirtualWindow`.
+- `FlexibleDimension::ZERO` has been removed, and now `FlexibleDimension`
+  implements `Zero` which defines an associated constant of the same name and
+  purpose.
 
 ### Fixed
 

src/styles.rs

@@ -649,9 +649,15 @@ pub enum FlexibleDimension {
     Dimension(Dimension),
 }
 
-impl FlexibleDimension {
-    /// A dimension of 0 pixels.
-    pub const ZERO: Self = Self::Dimension(Dimension::ZERO);
+impl Zero for FlexibleDimension {
+    const ZERO: Self = Self::Dimension(Dimension::ZERO);
+
+    fn is_zero(&self) -> bool {
+        match self {
+            FlexibleDimension::Auto => false,
+            FlexibleDimension::Dimension(dim) => dim.is_zero(),
+        }
+    }
 }
 
 impl Debug for FlexibleDimension {

src/widgets/align.rs

@@ -1,7 +1,7 @@
 use std::fmt::Debug;
 
 use figures::units::UPx;
-use figures::{Fraction, IntoSigned, Point, Rect, ScreenScale, Size};
+use figures::{Fraction, IntoSigned, Point, Rect, ScreenScale, Size, Zero};
 
 use crate::context::{AsEventContext, EventContext, LayoutContext};
 use crate::styles::{Edges, FlexibleDimension};