macOS: new window can inherit font size

This is the second part of #281 and adds the same mechanism that was
added for tabs in #296 for windows.

It works exactly the same way.

include/ghostty.h

@@ -234,6 +234,7 @@ typedef enum {
     GHOSTTY_BINDING_COPY_TO_CLIPBOARD,
     GHOSTTY_BINDING_PASTE_FROM_CLIPBOARD,
     GHOSTTY_BINDING_NEW_TAB,
+    GHOSTTY_BINDING_NEW_WINDOW,
 } ghostty_binding_action_e;
 
 // Fully defined types. This MUST be kept in sync with equivalent Zig
@@ -253,6 +254,7 @@ typedef const char* (*ghostty_runtime_read_clipboard_cb)(void *, ghostty_clipboa
 typedef void (*ghostty_runtime_write_clipboard_cb)(void *, const char *, ghostty_clipboard_e);
 typedef void (*ghostty_runtime_new_split_cb)(void *, ghostty_split_direction_e);
 typedef void (*ghostty_runtime_new_tab_cb)(void *, ghostty_surface_config_s);
+typedef void (*ghostty_runtime_new_window_cb)(void *, ghostty_surface_config_s);
 typedef void (*ghostty_runtime_close_surface_cb)(void *, bool);
 typedef void (*ghostty_runtime_focus_split_cb)(void *, ghostty_split_focus_direction_e);
 typedef void (*ghostty_runtime_goto_tab_cb)(void *, int32_t);
@@ -268,6 +270,7 @@ typedef struct {
     ghostty_runtime_write_clipboard_cb write_clipboard_cb;
     ghostty_runtime_new_split_cb new_split_cb;
     ghostty_runtime_new_tab_cb new_tab_cb;
+    ghostty_runtime_new_window_cb new_window_cb;
     ghostty_runtime_close_surface_cb close_surface_cb;
     ghostty_runtime_focus_split_cb focus_split_cb;
     ghostty_runtime_goto_tab_cb goto_tab_cb;

macos/Sources/AppDelegate.swift

@@ -77,7 +77,7 @@ class AppDelegate: NSObject, NSApplicationDelegate, ObservableObject {
     }
     
     @IBAction func newWindow(_ sender: Any?) {
-        windowManager.addNewWindow()
+        windowManager.newWindow()
     }
     
     @IBAction func newTab(_ sender: Any?) {

macos/Sources/Features/Primary Window/PrimaryWindowManager.swift

@@ -46,21 +46,32 @@ class PrimaryWindowManager {
     init(ghostty: Ghostty.AppState) {
         self.ghostty = ghostty
         
-        // Register self as observer for the NewTab notification that
+        // Register self as observer for the NewTab/NewWindow notifications that
-        // is triggered via callback from Zig code.
+        // are triggered via callback from Zig code.
-        NotificationCenter.default.addObserver(
+        let center = NotificationCenter.default;
+        center.addObserver(
             self,
             selector: #selector(onNewTab),
             name: Ghostty.Notification.ghosttyNewTab,
             object: nil)
+        center.addObserver(
+            self,
+            selector: #selector(onNewWindow),
+            name: Ghostty.Notification.ghosttyNewWindow,
+            object: nil)
     }
     
     deinit {
-        // Clean up the observer.
+        // Clean up the observers.
-        NotificationCenter.default.removeObserver(
+        let center = NotificationCenter.default;
+        center.removeObserver(
             self,
             name: Ghostty.Notification.ghosttyNewTab,
             object: nil)
+        center.removeObserver(
+            self,
+            name: Ghostty.Notification.ghosttyNewWindow,
+            object: nil)
     }
     
     /// Add the initial window for the application. This should only be called once from the AppDelegate.
@@ -73,12 +84,33 @@ class PrimaryWindowManager {
         }
     }
     
-    func addNewWindow() {
+    func newWindow() {
-        guard let controller = createWindowController() else { return }
+        if let window = mainWindow as? PrimaryWindow {
+            // If we already have a window, we go through Zig core code, which calls back into Swift.
+            self.triggerNewWindow(withParent: window)
+        } else {
+            self.addNewWindow()
+        }
+    }
+    
+    func triggerNewWindow(withParent window: PrimaryWindow) {
+        guard let surface = window.focusedSurfaceWrapper.surface else { return }
+        ghostty.newWindow(surface: surface)
+    }
+    
+    func addNewWindow(withBaseConfig config: ghostty_surface_config_s? = nil) {
+        guard let controller = createWindowController(withBaseConfig: config) else { return }
         guard let newWindow = addManagedWindow(windowController: controller)?.window else { return }
         newWindow.makeKeyAndOrderFront(nil)
     }
     
+    @objc private func onNewWindow(notification: SwiftUI.Notification) {
+        let configAny = notification.userInfo?[Ghostty.Notification.NewWindowKey]
+        let config = configAny as? ghostty_surface_config_s
+        
+        self.addNewWindow(withBaseConfig: config)
+    }
+    
     // triggerNewTab tells the Zig core code to create a new tab, which then calls
     // back into Swift code.
     func triggerNewTab(for window: PrimaryWindow) {

macos/Sources/Ghostty/AppState.swift

@@ -62,6 +62,7 @@ extension Ghostty {
                 write_clipboard_cb: { userdata, str, loc in AppState.writeClipboard(userdata, string: str, location: loc) },
                 new_split_cb: { userdata, direction in AppState.newSplit(userdata, direction: direction) },
                 new_tab_cb: { userdata, surfaceConfig in AppState.newTab(userdata, config: surfaceConfig) },
+                new_window_cb: { userdata, surfaceConfig in AppState.newWindow(userdata, config: surfaceConfig) },
                 close_surface_cb: { userdata, processAlive in AppState.closeSurface(userdata, processAlive: processAlive) },
                 focus_split_cb: { userdata, direction in AppState.focusSplit(userdata, direction: direction) },
                 goto_tab_cb: { userdata, n in AppState.gotoTab(userdata, n: n) },
@@ -142,6 +143,10 @@ extension Ghostty {
             ghostty_surface_binding_action(surface, GHOSTTY_BINDING_NEW_TAB, nil)
         }
         
+        func newWindow(surface: ghostty_surface_t) {
+            ghostty_surface_binding_action(surface, GHOSTTY_BINDING_NEW_WINDOW, nil)
+        }
+        
         func split(surface: ghostty_surface_t, direction: ghostty_split_direction_e) {
             ghostty_surface_split(surface, direction)
         }
@@ -266,13 +271,24 @@ extension Ghostty {
         static func newTab(_ userdata: UnsafeMutableRawPointer?, config: ghostty_surface_config_s) {
             guard let surface = self.surfaceUserdata(from: userdata) else { return }
             
-            var userInfo: [AnyHashable : Any] = [:];
-            userInfo[Notification.NewTabKey] = config;
-            
             NotificationCenter.default.post(
                 name: Notification.ghosttyNewTab,
                 object: surface,
-                userInfo: userInfo
+                userInfo: [
+                    Notification.NewTabKey: config
+                ]
+            )
+        }
+        
+        static func newWindow(_ userdata: UnsafeMutableRawPointer?, config: ghostty_surface_config_s) {
+            guard let surface = self.surfaceUserdata(from: userdata) else { return }
+            
+            NotificationCenter.default.post(
+                name: Notification.ghosttyNewWindow,
+                object: surface,
+                userInfo: [
+                    Notification.NewWindowKey: config
+                ]
             )
         }
         

macos/Sources/Ghostty/Package.swift

@@ -79,9 +79,13 @@ extension Ghostty.Notification {
     static let ghosttyGotoTab = Notification.Name("com.mitchellh.ghostty.gotoTab")
     static let GotoTabKey = ghosttyGotoTab.rawValue
     
-    /// New tab. Has base surface config requestesd in userinfo.
+    /// New tab. Has base surface config requested in userinfo.
     static let ghosttyNewTab = Notification.Name("com.mitchellh.ghostty.newTab")
     static let NewTabKey = ghosttyNewTab.rawValue
+    
+    /// New window. Has base surface config requested in userinfo.
+    static let ghosttyNewWindow = Notification.Name("com.mitchellh.ghostty.newWindow")
+    static let NewWindowKey = ghosttyNewWindow.rawValue
 
     /// Toggle fullscreen of current window
     static let ghosttyToggleFullscreen = Notification.Name("com.mitchellh.ghostty.toggleFullscreen")

src/Surface.zig

@@ -2119,11 +2119,15 @@ pub fn performBindingAction(self: *Surface, action: input.Binding.Action) !void
         } else log.warn("dev mode was not compiled into this binary", .{}),
 
         .new_window => {
-            _ = self.app_mailbox.push(.{
+            if (@hasDecl(apprt.Surface, "newWindow")) {
-                .new_window = .{
+                try self.rt_surface.newWindow();
-                    .parent = self,
+            } else {
-                },
+                _ = self.app_mailbox.push(.{
-            }, .{ .instant = {} });
+                    .new_window = .{
+                        .parent = self,
+                    },
+                }, .{ .instant = {} });
+            }
         },
 
         .new_tab => {

src/apprt/embedded.zig

@@ -62,6 +62,9 @@ pub const App = struct {
         /// New tab with options.
         new_tab: ?*const fn (SurfaceUD, apprt.Surface.Options) callconv(.C) void = null,
 
+        /// New window with options.
+        new_window: ?*const fn (SurfaceUD, apprt.Surface.Options) callconv(.C) void = null,
+
         /// Close the current surface given by this function.
         close_surface: ?*const fn (SurfaceUD, bool) callconv(.C) void = null,
 
@@ -615,14 +618,29 @@ pub const Surface = struct {
             return;
         };
 
+        const options = self.newSurfaceOptions();
+        func(self.opts.userdata, options);
+    }
+
+    pub fn newWindow(self: *const Surface) !void {
+        const func = self.app.opts.new_window orelse {
+            log.info("runtime embedder does not support new_window", .{});
+            return;
+        };
+
+        const options = self.newSurfaceOptions();
+        func(self.opts.userdata, options);
+    }
+
+    fn newSurfaceOptions(self: *const Surface) apprt.Surface.Options {
         const font_size: u16 = font_size: {
             if (!self.app.config.@"window-inherit-font-size") break :font_size 0;
             break :font_size self.core_surface.font_size.points;
         };
 
-        func(self.opts.userdata, .{
+        return .{
             .font_size = font_size,
-        });
+        };
     }
 
     /// The cursor position from the host directly is in screen coordinates but
@@ -855,6 +873,7 @@ pub const CAPI = struct {
             .copy_to_clipboard => .{ .copy_to_clipboard = {} },
             .paste_from_clipboard => .{ .paste_from_clipboard = {} },
             .new_tab => .{ .new_tab = {} },
+            .new_window => .{ .new_window = {} },
         };
 
         ptr.core_surface.performBindingAction(action) catch |err| {

src/input/Binding.zig

@@ -277,6 +277,7 @@ pub const Key = enum(c_int) {
     copy_to_clipboard,
     paste_from_clipboard,
     new_tab,
+    new_window,
 };
 
 /// Trigger is the associated key state that can trigger an action.