vim: Add scroll keybindings for the OutlinePanel (#42438)

Closes #ISSUE

```json
  {
    "context": "OutlinePanel && not_editing",
    "bindings": {
      "enter": "editor::ToggleFocus",
      "/": "menu::Cancel",
      "ctrl-u": "outline_panel::ScrollUp",
      "ctrl-d": "outline_panel::ScrollDown",
      "z t": "outline_panel::ScrollCursorTop",
      "z z": "outline_panel::ScrollCursorCenter",
      "z b": "outline_panel::ScrollCursorBottom"
    }
  },
  {
    "context": "OutlinePanel && editing",
    "bindings": {
      "enter": "menu::Cancel"
    }
  },
```

Release Notes:

- Added scroll keybindings for the OutlinePanel

---------

Co-authored-by: Ben Kunkle <ben@zed.dev>

Cargo.lock

@@ -18138,6 +18138,7 @@ dependencies = [
  "menu",
  "multi_buffer",
  "nvim-rs",
+ "outline_panel",
  "parking_lot",
  "perf",
  "picker",

assets/keymaps/vim.json

@@ -970,10 +970,38 @@
   {
     "context": "OutlinePanel && not_editing",
     "bindings": {
-      "j": "menu::SelectNext",
-      "k": "menu::SelectPrevious",
+      "h": "outline_panel::CollapseSelectedEntry",
+      "j": "vim::MenuSelectNext",
+      "k": "vim::MenuSelectPrevious",
+      "down": "vim::MenuSelectNext",
+      "up": "vim::MenuSelectPrevious",
+      "l": "outline_panel::ExpandSelectedEntry",
       "shift-g": "menu::SelectLast",
       "g g": "menu::SelectFirst",
+      "-": "outline_panel::SelectParent",
+      "enter": "editor::ToggleFocus",
+      "/": "menu::Cancel",
+      "ctrl-u": "outline_panel::ScrollUp",
+      "ctrl-d": "outline_panel::ScrollDown",
+      "z t": "outline_panel::ScrollCursorTop",
+      "z z": "outline_panel::ScrollCursorCenter",
+      "z b": "outline_panel::ScrollCursorBottom",
+      "0": ["vim::Number", 0],
+      "1": ["vim::Number", 1],
+      "2": ["vim::Number", 2],
+      "3": ["vim::Number", 3],
+      "4": ["vim::Number", 4],
+      "5": ["vim::Number", 5],
+      "6": ["vim::Number", 6],
+      "7": ["vim::Number", 7],
+      "8": ["vim::Number", 8],
+      "9": ["vim::Number", 9],
+    },
+  },
+  {
+    "context": "OutlinePanel && editing",
+    "bindings": {
+      "enter": "menu::Cancel",
     },
   },
   {

crates/outline_panel/src/outline_panel.rs

@@ -75,6 +75,16 @@ actions!(
         OpenSelectedEntry,
         /// Reveals the selected item in the system file manager.
         RevealInFileManager,
+        /// Scroll half a page upwards
+        ScrollUp,
+        /// Scroll half a page downwards
+        ScrollDown,
+        /// Scroll until the cursor displays at the center
+        ScrollCursorCenter,
+        /// Scroll until the cursor displays at the top
+        ScrollCursorTop,
+        /// Scroll until the cursor displays at the bottom
+        ScrollCursorBottom,
         /// Selects the parent of the current entry.
         SelectParent,
         /// Toggles the pin status of the active editor.
@@ -100,6 +110,7 @@ pub struct OutlinePanel {
     active: bool,
     pinned: bool,
     scroll_handle: UniformListScrollHandle,
+    rendered_entries_len: usize,
     context_menu: Option<(Entity<ContextMenu>, Point<Pixels>, Subscription)>,
     focus_handle: FocusHandle,
     pending_serialization: Task<Option<()>>,
@@ -839,6 +850,7 @@ impl OutlinePanel {
                 fs: workspace.app_state().fs.clone(),
                 max_width_item_index: None,
                 scroll_handle,
+                rendered_entries_len: 0,
                 focus_handle,
                 filter_editor,
                 fs_entries: Vec::new(),
@@ -1149,6 +1161,70 @@ impl OutlinePanel {
         }
     }
 
+    fn scroll_up(&mut self, _: &ScrollUp, window: &mut Window, cx: &mut Context<Self>) {
+        for _ in 0..self.rendered_entries_len / 2 {
+            window.dispatch_action(SelectPrevious.boxed_clone(), cx);
+        }
+    }
+
+    fn scroll_down(&mut self, _: &ScrollDown, window: &mut Window, cx: &mut Context<Self>) {
+        for _ in 0..self.rendered_entries_len / 2 {
+            window.dispatch_action(SelectNext.boxed_clone(), cx);
+        }
+    }
+
+    fn scroll_cursor_center(
+        &mut self,
+        _: &ScrollCursorCenter,
+        _: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        if let Some(selected_entry) = self.selected_entry() {
+            let index = self
+                .cached_entries
+                .iter()
+                .position(|cached_entry| &cached_entry.entry == selected_entry);
+            if let Some(index) = index {
+                self.scroll_handle
+                    .scroll_to_item_strict(index, ScrollStrategy::Center);
+                cx.notify();
+            }
+        }
+    }
+
+    fn scroll_cursor_top(&mut self, _: &ScrollCursorTop, _: &mut Window, cx: &mut Context<Self>) {
+        if let Some(selected_entry) = self.selected_entry() {
+            let index = self
+                .cached_entries
+                .iter()
+                .position(|cached_entry| &cached_entry.entry == selected_entry);
+            if let Some(index) = index {
+                self.scroll_handle
+                    .scroll_to_item_strict(index, ScrollStrategy::Top);
+                cx.notify();
+            }
+        }
+    }
+
+    fn scroll_cursor_bottom(
+        &mut self,
+        _: &ScrollCursorBottom,
+        _: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        if let Some(selected_entry) = self.selected_entry() {
+            let index = self
+                .cached_entries
+                .iter()
+                .position(|cached_entry| &cached_entry.entry == selected_entry);
+            if let Some(index) = index {
+                self.scroll_handle
+                    .scroll_to_item_strict(index, ScrollStrategy::Bottom);
+                cx.notify();
+            }
+        }
+    }
+
     fn select_next(&mut self, _: &SelectNext, window: &mut Window, cx: &mut Context<Self>) {
         if let Some(entry_to_select) = self.selected_entry().and_then(|selected_entry| {
             self.cached_entries
@@ -4578,6 +4654,7 @@ impl OutlinePanel {
                     "entries",
                     items_len,
                     cx.processor(move |outline_panel, range: Range<usize>, window, cx| {
+                        outline_panel.rendered_entries_len = range.end - range.start;
                         let entries = outline_panel.cached_entries.get(range);
                         entries
                             .map(|entries| entries.to_vec())
@@ -4970,7 +5047,12 @@ impl Render for OutlinePanel {
             .key_context(self.dispatch_context(window, cx))
             .on_action(cx.listener(Self::open_selected_entry))
             .on_action(cx.listener(Self::cancel))
+            .on_action(cx.listener(Self::scroll_up))
+            .on_action(cx.listener(Self::scroll_down))
             .on_action(cx.listener(Self::select_next))
+            .on_action(cx.listener(Self::scroll_cursor_center))
+            .on_action(cx.listener(Self::scroll_cursor_top))
+            .on_action(cx.listener(Self::scroll_cursor_bottom))
             .on_action(cx.listener(Self::select_previous))
             .on_action(cx.listener(Self::select_first))
             .on_action(cx.listener(Self::select_last))

crates/vim/Cargo.toml

@@ -66,6 +66,7 @@ lsp = { workspace = true, features = ["test-support"] }
 markdown_preview.workspace = true
 parking_lot.workspace = true
 project_panel.workspace = true
+outline_panel.workspace = true
 release_channel.workspace = true
 semver.workspace = true
 settings_ui.workspace = true

crates/vim/src/test/vim_test_context.rs

@@ -23,6 +23,7 @@ impl VimTestContext {
             release_channel::init(Version::new(0, 0, 0), cx);
             command_palette::init(cx);
             project_panel::init(cx);
+            outline_panel::init(cx);
             git_ui::init(cx);
             crate::init(cx);
             search::init(cx);