Make `widget::Tree` mutable in `Widget::layout`

3 files changed, 20 insertions, 13 deletions

diff --git a/widget/src/pane_grid.rs b/widget/src/pane_grid.rs
index 366d9a66..6e2b39a4 100644
--- a/widget/src/pane_grid.rs
+++ b/widget/src/pane_grid.rs
@@ -275,7 +275,7 @@ where
 
     fn layout(
         &self,
-        tree: &Tree,
+        tree: &mut Tree,
         renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
@@ -475,7 +475,7 @@ where
 
 /// Calculates the [`Layout`] of a [`PaneGrid`].
 pub fn layout<Renderer, T>(
-    tree: &Tree,
+    tree: &mut Tree,
     renderer: &Renderer,
     limits: &layout::Limits,
     node: &Node,
@@ -483,14 +483,19 @@ pub fn layout<Renderer, T>(
     height: Length,
     spacing: f32,
     contents: impl Iterator<Item = (Pane, T)>,
-    layout_content: impl Fn(T, &Tree, &Renderer, &layout::Limits) -> layout::Node,
+    layout_content: impl Fn(
+        T,
+        &mut Tree,
+        &Renderer,
+        &layout::Limits,
+    ) -> layout::Node,
 ) -> layout::Node {
     let limits = limits.width(width).height(height);
     let size = limits.resolve(Size::ZERO);
 
     let regions = node.pane_regions(spacing, size);
     let children = contents
-        .zip(tree.children.iter())
+        .zip(tree.children.iter_mut())
         .filter_map(|((pane, content), tree)| {
             let region = regions.get(&pane)?;
             let size = Size::new(region.width, region.height);
diff --git a/widget/src/pane_grid/content.rs b/widget/src/pane_grid/content.rs
index 8a74b4b9..5dbc5496 100644
--- a/widget/src/pane_grid/content.rs
+++ b/widget/src/pane_grid/content.rs
@@ -150,7 +150,7 @@ where
 
     pub(crate) fn layout(
         &self,
-        tree: &Tree,
+        tree: &mut Tree,
         renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
@@ -158,7 +158,7 @@ where
             let max_size = limits.max();
 
             let title_bar_layout = title_bar.layout(
-                &tree.children[1],
+                &mut tree.children[1],
                 renderer,
                 &layout::Limits::new(Size::ZERO, max_size),
             );
@@ -166,7 +166,7 @@ where
             let title_bar_size = title_bar_layout.size();
 
             let mut body_layout = self.body.as_widget().layout(
-                &tree.children[0],
+                &mut tree.children[0],
                 renderer,
                 &layout::Limits::new(
                     Size::ZERO,
@@ -184,9 +184,11 @@ where
                 vec![title_bar_layout, body_layout],
             )
         } else {
-            self.body
-                .as_widget()
-                .layout(&tree.children[0], renderer, limits)
+            self.body.as_widget().layout(
+                &mut tree.children[0],
+                renderer,
+                limits,
+            )
         }
     }
 
diff --git a/widget/src/pane_grid/title_bar.rs b/widget/src/pane_grid/title_bar.rs
index c0fb9936..8a4523e8 100644
--- a/widget/src/pane_grid/title_bar.rs
+++ b/widget/src/pane_grid/title_bar.rs
@@ -213,7 +213,7 @@ where
 
     pub(crate) fn layout(
         &self,
-        tree: &Tree,
+        tree: &mut Tree,
         renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
@@ -221,7 +221,7 @@ where
         let max_size = limits.max();
 
         let title_layout = self.content.as_widget().layout(
-            &tree.children[0],
+            &mut tree.children[0],
             renderer,
             &layout::Limits::new(Size::ZERO, max_size),
         );
@@ -230,7 +230,7 @@ where
 
         let mut node = if let Some(controls) = &self.controls {
             let mut controls_layout = controls.as_widget().layout(
-                &tree.children[1],
+                &mut tree.children[1],
                 renderer,
                 &layout::Limits::new(Size::ZERO, max_size),
             );