Add ZoomIn and ZoomOut actions for independent zoom control (#44587)

pedroni created 1 week ago

Closes #14472

Introduces `workspace::ZoomIn` and `workspace::ZoomOut` actions that
complement the existing `workspace::ToggleZoom` action. ZoomIn only
zooms if not already zoomed, and ZoomOut only zooms out if currently
zoomed. This enables composing zoom actions with
`workspace::SendKeystrokes` for workflows like "focus terminal then zoom
in".


<details><summary>Example usage</summary>
<p>

Example keybindings:

```json
[
  {
    "bindings": {
      "ctrl-cmd-,": "terminal_panel::ToggleFocus",
      "ctrl-cmd-.": "workspace::ZoomIn",
    }
  },
  {
    "context": "Terminal",
    "bindings": {
      "cmd-.": "terminal_panel::ToggleFocus"
    }
  },
  {
    "context": "!Terminal",
    "bindings": {
      "cmd-.": ["workspace::SendKeystrokes", "ctrl-cmd-, ctrl-cmd-."]
    }
  },
]
```

Demo:


https://github.com/user-attachments/assets/1b1deda9-7775-4d78-a281-dc9622032ead

</p>
</details> 



Release Notes: 

- Added the actions: `workspace::ZoomIn` and `workspace::ZoomOut` that
complement the existing `workspace::ToggleZoom` action

Change summary

crates/workspace/src/pane.rs      |  23 +++++++
crates/workspace/src/workspace.rs | 103 +++++++++++++++++++++++++++++++++
2 files changed, 125 insertions(+), 1 deletion(-)

Detailed changes

crates/workspace/src/pane.rs

@@ -1,7 +1,7 @@
 use crate::{
     CloseWindow, NewFile, NewTerminal, OpenInTerminal, OpenOptions, OpenTerminal, OpenVisible,
     SplitDirection, ToggleFileFinder, ToggleProjectSymbols, ToggleZoom, Workspace,
-    WorkspaceItemBuilder,
+    WorkspaceItemBuilder, ZoomIn, ZoomOut,
     invalid_item_view::InvalidItemView,
     item::{
         ActivateOnClose, ClosePosition, Item, ItemBufferKind, ItemHandle, ItemSettings,
@@ -1306,6 +1306,25 @@ impl Pane {
         }
     }
 
+    pub fn zoom_in(&mut self, _: &ZoomIn, window: &mut Window, cx: &mut Context<Self>) {
+        if !self.can_toggle_zoom {
+            cx.propagate();
+        } else if !self.zoomed && !self.items.is_empty() {
+            if !self.focus_handle.contains_focused(window, cx) {
+                cx.focus_self(window);
+            }
+            cx.emit(Event::ZoomIn);
+        }
+    }
+
+    pub fn zoom_out(&mut self, _: &ZoomOut, _window: &mut Window, cx: &mut Context<Self>) {
+        if !self.can_toggle_zoom {
+            cx.propagate();
+        } else if self.zoomed {
+            cx.emit(Event::ZoomOut);
+        }
+    }
+
     pub fn activate_item(
         &mut self,
         index: usize,
@@ -3900,6 +3919,8 @@ impl Render for Pane {
                 cx.emit(Event::JoinAll);
             }))
             .on_action(cx.listener(Pane::toggle_zoom))
+            .on_action(cx.listener(Pane::zoom_in))
+            .on_action(cx.listener(Pane::zoom_out))
             .on_action(cx.listener(Self::navigate_backward))
             .on_action(cx.listener(Self::navigate_forward))
             .on_action(

crates/workspace/src/workspace.rs

@@ -272,6 +272,10 @@ actions!(
         ToggleRightDock,
         /// Toggles zoom on the active pane.
         ToggleZoom,
+        /// Zooms in on the active pane.
+        ZoomIn,
+        /// Zooms out of the active pane.
+        ZoomOut,
         /// Stops following a collaborator.
         Unfollow,
         /// Restores the banner.
@@ -9594,6 +9598,105 @@ mod tests {
         });
     }
 
+    #[gpui::test]
+    async fn test_pane_zoom_in_out(cx: &mut TestAppContext) {
+        init_test(cx);
+        let fs = FakeFs::new(cx.executor());
+
+        let project = Project::test(fs, [], cx).await;
+        let (workspace, cx) =
+            cx.add_window_view(|window, cx| Workspace::test_new(project, window, cx));
+
+        let pane = workspace.update_in(cx, |workspace, _window, _cx| {
+            workspace.active_pane().clone()
+        });
+
+        // Add an item to the pane so it can be zoomed
+        workspace.update_in(cx, |workspace, window, cx| {
+            let item = cx.new(TestItem::new);
+            workspace.add_item(pane.clone(), Box::new(item), None, true, true, window, cx);
+        });
+
+        // Initially not zoomed
+        workspace.update_in(cx, |workspace, _window, cx| {
+            assert!(!pane.read(cx).is_zoomed(), "Pane starts unzoomed");
+            assert!(
+                workspace.zoomed.is_none(),
+                "Workspace should track no zoomed pane"
+            );
+            assert!(pane.read(cx).items_len() > 0, "Pane should have items");
+        });
+
+        // Zoom In
+        pane.update_in(cx, |pane, window, cx| {
+            pane.zoom_in(&crate::ZoomIn, window, cx);
+        });
+
+        workspace.update_in(cx, |workspace, window, cx| {
+            assert!(
+                pane.read(cx).is_zoomed(),
+                "Pane should be zoomed after ZoomIn"
+            );
+            assert!(
+                workspace.zoomed.is_some(),
+                "Workspace should track the zoomed pane"
+            );
+            assert!(
+                pane.read(cx).focus_handle(cx).contains_focused(window, cx),
+                "ZoomIn should focus the pane"
+            );
+        });
+
+        // Zoom In again is a no-op
+        pane.update_in(cx, |pane, window, cx| {
+            pane.zoom_in(&crate::ZoomIn, window, cx);
+        });
+
+        workspace.update_in(cx, |workspace, window, cx| {
+            assert!(pane.read(cx).is_zoomed(), "Second ZoomIn keeps pane zoomed");
+            assert!(
+                workspace.zoomed.is_some(),
+                "Workspace still tracks zoomed pane"
+            );
+            assert!(
+                pane.read(cx).focus_handle(cx).contains_focused(window, cx),
+                "Pane remains focused after repeated ZoomIn"
+            );
+        });
+
+        // Zoom Out
+        pane.update_in(cx, |pane, window, cx| {
+            pane.zoom_out(&crate::ZoomOut, window, cx);
+        });
+
+        workspace.update_in(cx, |workspace, _window, cx| {
+            assert!(
+                !pane.read(cx).is_zoomed(),
+                "Pane should unzoom after ZoomOut"
+            );
+            assert!(
+                workspace.zoomed.is_none(),
+                "Workspace clears zoom tracking after ZoomOut"
+            );
+        });
+
+        // Zoom Out again is a no-op
+        pane.update_in(cx, |pane, window, cx| {
+            pane.zoom_out(&crate::ZoomOut, window, cx);
+        });
+
+        workspace.update_in(cx, |workspace, _window, cx| {
+            assert!(
+                !pane.read(cx).is_zoomed(),
+                "Second ZoomOut keeps pane unzoomed"
+            );
+            assert!(
+                workspace.zoomed.is_none(),
+                "Workspace remains without zoomed pane"
+            );
+        });
+    }
+
     #[gpui::test]
     async fn test_toggle_all_docks(cx: &mut gpui::TestAppContext) {
         init_test(cx);