macos: menu bar to split

include/ghostty.h

@@ -253,6 +253,7 @@ void ghostty_surface_mouse_pos(ghostty_surface_t, double, double);
 void ghostty_surface_mouse_scroll(ghostty_surface_t, double, double);
 void ghostty_surface_ime_point(ghostty_surface_t, double *, double *);
 void ghostty_surface_request_close(ghostty_surface_t);
+void ghostty_surface_split(ghostty_surface_t, ghostty_split_direction_e);
 
 #ifdef __cplusplus
 }

macos/Sources/Ghostty/AppState.swift

@@ -88,6 +88,10 @@ extension Ghostty {
             ghostty_surface_request_close(surface)
         }
         
+        func split(surface: ghostty_surface_t, direction: ghostty_split_direction_e) {
+            ghostty_surface_split(surface, direction)
+        }
+        
         // MARK: Ghostty Callbacks
         
         static func newSplit(_ userdata: UnsafeMutableRawPointer?, direction: ghostty_split_direction_e) {

macos/Sources/GhosttyApp.swift

@@ -31,6 +31,9 @@ struct GhosttyApp: App {
             CommandGroup(after: .newItem) {
                 Button("New Tab", action: Self.newTab).keyboardShortcut("t", modifiers: [.command])
                 Divider()
+                Button("Split Horizontally", action: splitHorizontally).keyboardShortcut("d", modifiers: [.command])
+                Button("Split Vertically", action: splitVertically).keyboardShortcut("d", modifiers: [.command, .shift])
+                Divider()
                 Button("Close", action: close).keyboardShortcut("w", modifiers: [.command])
                 Button("Close Window", action: Self.closeWindow).keyboardShortcut("w", modifiers: [.command, .shift])
              }
@@ -61,6 +64,18 @@ struct GhosttyApp: App {
         guard let surface = surfaceView.surface else { return }
         ghostty.requestClose(surface: surface)
     }
+    
+    func splitHorizontally() {
+        guard let surfaceView = focusedSurface else { return }
+        guard let surface = surfaceView.surface else { return }
+        ghostty.split(surface: surface, direction: GHOSTTY_SPLIT_RIGHT)
+    }
+    
+    func splitVertically() {
+        guard let surfaceView = focusedSurface else { return }
+        guard let surface = surfaceView.surface else { return }
+        ghostty.split(surface: surface, direction: GHOSTTY_SPLIT_DOWN)
+    }
 }
 
 class AppDelegate: NSObject, NSApplicationDelegate {

src/apprt/embedded.zig

@@ -476,4 +476,9 @@ pub const CAPI = struct {
     export fn ghostty_surface_request_close(ptr: *Surface) void {
         ptr.closeSurface() catch {};
     }
+
+    /// Request that the surface split in the given direction.
+    export fn ghostty_surface_split(ptr: *Surface, direction: input.SplitDirection) void {
+        ptr.newSplit(direction) catch {};
+    }
 };