dock: Add set_dock_collapsible to support setting the Docks to be collapsible or not. (#445)

Close #442 

In this case, the left Dock is not collapsible:

<img width="1165" alt="image"
src="https://github.com/user-attachments/assets/21422cdd-d686-4931-9285-925b8e8d3343">

crates/app/src/story_workspace.rs

@@ -204,6 +204,15 @@ impl StoryWorkspace {
 
         dock_area.update(cx, |dock_area, cx| {
             dock_area.load(state, cx).context("load layout")?;
+            dock_area.set_dock_collapsible(
+                Edges {
+                    left: true,
+                    bottom: true,
+                    right: true,
+                    ..Default::default()
+                },
+                cx,
+            );
 
             Ok::<(), anyhow::Error>(())
         })

crates/ui/src/dock/dock.rs

@@ -65,6 +65,11 @@ pub struct Dock {
     /// The size is means the width or height of the Dock, if the placement is left or right, the size is width, otherwise the size is height.
     pub(super) size: Pixels,
     pub(super) open: bool,
+    /// Whether the Dock is collapsible, default: true
+    pub(super) collapsible: bool,
+
+    // Runtime state
+    /// Whether the Dock is resizing
     is_resizing: bool,
 }
 
@@ -93,6 +98,7 @@ impl Dock {
             dock_area,
             panel,
             open: true,
+            collapsible: true,
             size: px(200.0),
             is_resizing: false,
         }
@@ -110,6 +116,17 @@ impl Dock {
         Self::new(dock_area, DockPlacement::Right, cx)
     }
 
+    /// Update the Dock to be collapsible or not.
+    ///
+    /// And if the Dock is not collapsible, it will be open.
+    pub fn set_collapsible(&mut self, collapsible: bool, cx: &mut ViewContext<Self>) {
+        self.collapsible = collapsible;
+        if !collapsible {
+            self.open = true
+        }
+        cx.notify();
+    }
+
     pub(super) fn from_state(
         dock_area: WeakView<DockArea>,
         placement: DockPlacement,
@@ -137,6 +154,7 @@ impl Dock {
             panel,
             open,
             size,
+            collapsible: true,
             is_resizing: false,
         }
     }

crates/ui/src/dock/mod.rs

@@ -435,6 +435,55 @@ impl DockArea {
         }
     }
 
+    /// Set the dock at the given placement to be open or closed.
+    ///
+    /// Only the left, bottom, right dock can be toggled.
+    pub fn set_dock_collapsible(
+        &mut self,
+        collapsible_edges: Edges<bool>,
+        cx: &mut ViewContext<Self>,
+    ) {
+        if let Some(left_dock) = self.left_dock.as_ref() {
+            left_dock.update(cx, |dock, cx| {
+                dock.set_collapsible(collapsible_edges.left, cx);
+            });
+        }
+
+        if let Some(bottom_dock) = self.bottom_dock.as_ref() {
+            bottom_dock.update(cx, |dock, cx| {
+                dock.set_collapsible(collapsible_edges.bottom, cx);
+            });
+        }
+
+        if let Some(right_dock) = self.right_dock.as_ref() {
+            right_dock.update(cx, |dock, cx| {
+                dock.set_collapsible(collapsible_edges.right, cx);
+            });
+        }
+    }
+
+    /// Determine if the dock at the given placement is collapsible.
+    pub fn is_dock_collapsible(&self, placement: DockPlacement, cx: &AppContext) -> bool {
+        match placement {
+            DockPlacement::Left => self
+                .left_dock
+                .as_ref()
+                .map(|dock| dock.read(cx).collapsible)
+                .unwrap_or(false),
+            DockPlacement::Bottom => self
+                .bottom_dock
+                .as_ref()
+                .map(|dock| dock.read(cx).collapsible)
+                .unwrap_or(false),
+            DockPlacement::Right => self
+                .right_dock
+                .as_ref()
+                .map(|dock| dock.read(cx).collapsible)
+                .unwrap_or(false),
+            DockPlacement::Center => false,
+        }
+    }
+
     pub fn toggle_dock(&self, placement: DockPlacement, cx: &mut ViewContext<Self>) {
         let dock = match placement {
             DockPlacement::Left => &self.left_dock,

crates/ui/src/dock/panel.rs

@@ -57,11 +57,6 @@ pub trait Panel: EventEmitter<PanelEvent> + FocusableView {
         true
     }
 
-    /// Return true if the panel is collapsible, default is `false`.
-    fn collapsible(&self, _cx: &WindowContext) -> bool {
-        false
-    }
-
     /// The addition popup menu of the panel, default is `None`.
     fn popup_menu(&self, this: PopupMenu, _cx: &WindowContext) -> PopupMenu {
         this
@@ -84,7 +79,6 @@ pub trait PanelView: 'static + Send + Sync {
     fn title_style(&self, _cx: &WindowContext) -> Option<TitleStyle>;
     fn closeable(&self, cx: &WindowContext) -> bool;
     fn zoomable(&self, cx: &WindowContext) -> bool;
-    fn collapsible(&self, cx: &WindowContext) -> bool;
     fn popup_menu(&self, menu: PopupMenu, cx: &WindowContext) -> PopupMenu;
     fn toolbar_buttons(&self, cx: &WindowContext) -> Vec<Button>;
     fn view(&self) -> AnyView;
@@ -113,10 +107,6 @@ impl<T: Panel> PanelView for View<T> {
         self.read(cx).zoomable(cx)
     }
 
-    fn collapsible(&self, cx: &WindowContext) -> bool {
-        self.read(cx).collapsible(cx)
-    }
-
     fn popup_menu(&self, menu: PopupMenu, cx: &WindowContext) -> PopupMenu {
         self.read(cx).popup_menu(menu, cx)
     }

crates/ui/src/dock/tab_panel.rs

@@ -109,12 +109,6 @@ impl Panel for TabPanel {
             .unwrap_or(false)
     }
 
-    fn collapsible(&self, cx: &WindowContext) -> bool {
-        self.active_panel()
-            .map(|panel| panel.collapsible(cx))
-            .unwrap_or(false)
-    }
-
     fn popup_menu(&self, menu: PopupMenu, cx: &WindowContext) -> PopupMenu {
         if let Some(panel) = self.active_panel() {
             panel.popup_menu(menu, cx)
@@ -383,9 +377,12 @@ impl TabPanel {
             return None;
         }
 
-        let view_entity_id = cx.view().entity_id();
         let dock_area = self.dock_area.upgrade()?.read(cx);
+        if !dock_area.is_dock_collapsible(placement, cx) {
+            return None;
+        }
 
+        let view_entity_id = cx.view().entity_id();
         let toggle_button_panels = dock_area.toggle_button_panels;
 
         // Check if current TabPanel's entity_id matches the one stored in DockArea for this placement