macOS: new split can inherit font size

include/ghostty.h

@@ -252,7 +252,7 @@ typedef const ghostty_config_t (*ghostty_runtime_reload_config_cb)(void *);
 typedef void (*ghostty_runtime_set_title_cb)(void *, const char *);
 typedef const char* (*ghostty_runtime_read_clipboard_cb)(void *, ghostty_clipboard_e);
 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_split_cb)(void *, ghostty_split_direction_e, ghostty_surface_config_s);
 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);

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

@@ -105,7 +105,7 @@ class PrimaryWindowManager {
     }
     
     @objc private func onNewWindow(notification: SwiftUI.Notification) {
-        let configAny = notification.userInfo?[Ghostty.Notification.NewWindowKey]
+        let configAny = notification.userInfo?[Ghostty.Notification.NewSurfaceConfigKey]
         let config = configAny as? ghostty_surface_config_s
         
         self.addNewWindow(withBaseConfig: config)
@@ -130,7 +130,7 @@ class PrimaryWindowManager {
         guard let surfaceView = notification.object as? Ghostty.SurfaceView else { return }
         guard let window = surfaceView.window else { return }
         
-        let configAny = notification.userInfo?[Ghostty.Notification.NewTabKey]
+        let configAny = notification.userInfo?[Ghostty.Notification.NewSurfaceConfigKey]
         let config = configAny as? ghostty_surface_config_s
         
         self.addNewTab(to: window, withBaseConfig: config)

macos/Sources/Ghostty/AppState.swift

@@ -60,7 +60,7 @@ extension Ghostty {
                 set_title_cb: { userdata, title in AppState.setTitle(userdata, title: title) },
                 read_clipboard_cb: { userdata, loc in AppState.readClipboard(userdata, location: loc) },
                 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_split_cb: { userdata, direction, surfaceConfig in AppState.newSplit(userdata, direction: direction, config: surfaceConfig) },
                 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) },
@@ -164,10 +164,11 @@ extension Ghostty {
         
         // MARK: Ghostty Callbacks
         
-        static func newSplit(_ userdata: UnsafeMutableRawPointer?, direction: ghostty_split_direction_e) {
+        static func newSplit(_ userdata: UnsafeMutableRawPointer?, direction: ghostty_split_direction_e, config: ghostty_surface_config_s) {
             guard let surface = self.surfaceUserdata(from: userdata) else { return }
             NotificationCenter.default.post(name: Notification.ghosttyNewSplit, object: surface, userInfo: [
                 "direction": direction,
+                Notification.NewSurfaceConfigKey: config,
             ])
         }
         
@@ -275,7 +276,7 @@ extension Ghostty {
                 name: Notification.ghosttyNewTab,
                 object: surface,
                 userInfo: [
-                    Notification.NewTabKey: config
+                    Notification.NewSurfaceConfigKey: config
                 ]
             )
         }
@@ -287,7 +288,7 @@ extension Ghostty {
                 name: Notification.ghosttyNewWindow,
                 object: surface,
                 userInfo: [
-                    Notification.NewWindowKey: config
+                    Notification.NewSurfaceConfigKey: config
                 ]
             )
         }

macos/Sources/Ghostty/Ghostty.SplitView.swift

@@ -82,13 +82,13 @@ extension Ghostty {
             /// A container is always initialized from some prior leaf because a split has to originate
             /// from a non-split value. When initializing, we inherit the leaf's surface and then
             /// initialize a new surface for the new pane.
-            init(from: Leaf) {
+            init(from: Leaf, baseConfig: ghostty_surface_config_s? = nil) {
                 self.app = from.app
                 
                 // Initially, both topLeft and bottomRight are in the "nosplit"
                 // state since this is a new split.
                 self.topLeft = .noSplit(from)
-                self.bottomRight = .noSplit(.init(app, nil))
+                self.bottomRight = .noSplit(.init(app, baseConfig))
             }
         }
         
@@ -254,6 +254,9 @@ extension Ghostty {
         }
         
         private func onNewSplit(notification: SwiftUI.Notification) {
+            let configAny = notification.userInfo?[Ghostty.Notification.NewSurfaceConfigKey]
+            let config = configAny as? ghostty_surface_config_s
+
             // Determine our desired direction
             guard let directionAny = notification.userInfo?["direction"] else { return }
             guard let direction = directionAny as? ghostty_split_direction_e else { return }
@@ -270,7 +273,7 @@ extension Ghostty {
             }
             
             // Setup our new container since we are now split
-            let container = SplitNode.Container(from: leaf)
+            let container = SplitNode.Container(from: leaf, baseConfig: config)
             
             // Depending on the direction, change the parent node. This will trigger
             // the parent to relayout our views.

macos/Sources/Ghostty/Package.swift

@@ -64,6 +64,9 @@ extension Ghostty {
 }
 
 extension Ghostty.Notification {
+    /// Used to pass a configuration along when creating a new tab/window/split.
+    static let NewSurfaceConfigKey = "com.mitchellh.ghostty.newSurfaceConfig"
+    
     /// Posted when a new split is requested. The sending object will be the surface that had focus. The
     /// userdata has one key "direction" with the direction to split to.
     static let ghosttyNewSplit = Notification.Name("com.mitchellh.ghostty.newSplit")
@@ -81,11 +84,9 @@ extension Ghostty.Notification {
     
     /// 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/apprt/embedded.zig

@@ -57,7 +57,7 @@ pub const App = struct {
 
         /// Create a new split view. If the embedder doesn't support split
         /// views then this can be null.
-        new_split: ?*const fn (SurfaceUD, input.SplitDirection) callconv(.C) void = null,
+        new_split: ?*const fn (SurfaceUD, input.SplitDirection, apprt.Surface.Options) callconv(.C) void = null,
 
         /// New tab with options.
         new_tab: ?*const fn (SurfaceUD, apprt.Surface.Options) callconv(.C) void = null,
@@ -236,7 +236,8 @@ pub const Surface = struct {
             return;
         };
 
-        func(self.opts.userdata, direction);
+        const options = self.newSurfaceOptions();
+        func(self.opts.userdata, direction, options);
     }
 
     pub fn close(self: *const Surface, process_alive: bool) void {