feat(segmented_button): Support adding divider above items in vertical segmented button

src/widget/segmented_button/model/builder.rs

@@ -95,6 +95,11 @@ where
         self
     }
 
+    pub fn divider_above(mut self) -> Self {
+        self.model.0.divider_above_set(self.id, true);
+        self
+    }
+
     /// Defines an icon for the item.
     ///
     /// ```ignore

src/widget/segmented_button/model/entity.rs

@@ -83,6 +83,12 @@ where
         self
     }
 
+    #[allow(clippy::must_use_candidate, clippy::return_self_not_must_use)]
+    pub fn divider_above(self, divider_above: bool) -> Self {
+        self.model.divider_above_set(self.id, divider_above);
+        self
+    }
+
     /// Define an icon for the item.
     ///
     /// ```ignore

src/widget/segmented_button/model/mod.rs

@@ -58,6 +58,9 @@ pub struct Model<SelectionMode: Default> {
     /// The content used for drawing segmented items.
     pub(super) items: SlotMap<Entity, Settings>,
 
+    /// Divider optionally-defined for each item.
+    pub(super) divider_aboves: SecondaryMap<Entity, bool>,
+
     /// Icons optionally-defined for each item.
     pub(super) icons: SecondaryMap<Entity, Icon>,
 
@@ -200,6 +203,22 @@ where
             .and_then(|storage| storage.remove(id));
     }
 
+    pub fn divider_above(&self, id: Entity) -> Option<bool> {
+        self.divider_aboves.get(id).copied()
+    }
+
+    pub fn divider_above_set(&mut self, id: Entity, divider_above: bool) -> Option<bool> {
+        if !self.contains_item(id) {
+            return None;
+        }
+
+        self.divider_aboves.insert(id, divider_above)
+    }
+
+    pub fn divider_above_remove(&mut self, id: Entity) -> Option<bool> {
+        self.divider_aboves.remove(id)
+    }
+
     /// Enable or disable an item.
     ///
     /// ```ignore

src/widget/segmented_button/vertical.rs

@@ -57,7 +57,19 @@ where
                 .iter()
                 .copied()
                 .enumerate()
-                .map(move |(nth, key)| {
+                .flat_map(move |(nth, key)| {
+                    let mut divider = None;
+                    if self.model.divider_above(key).unwrap_or(false) && nth > 0 {
+                        let mut divider_bounds = bounds;
+                        divider_bounds.height = 1.0;
+                        divider_bounds.x += f32::from(self.button_padding[0]);
+                        divider_bounds.width -= f32::from(self.button_padding[0]);
+                        divider_bounds.width -= f32::from(self.button_padding[2]);
+                        divider = Some(ItemBounds::Divider(divider_bounds));
+
+                        bounds.y += divider_bounds.height + spacing;
+                    }
+
                     let mut layout_bounds = bounds;
 
                     let layout_size = state.internal_layout[nth].0;
@@ -66,7 +78,7 @@ where
 
                     bounds.y += layout_bounds.height + spacing;
 
-                    ItemBounds::Button(key, layout_bounds)
+                    std::iter::once(ItemBounds::Button(key, layout_bounds)).chain(divider)
                 }),
         )
     }