apprt/embedded: newSplit callback

include/ghostty.h

@@ -30,6 +30,7 @@ typedef void (*ghostty_runtime_wakeup_cb)(void *);
 typedef void (*ghostty_runtime_set_title_cb)(void *, const char *);
 typedef const char* (*ghostty_runtime_read_clipboard_cb)(void *);
 typedef void (*ghostty_runtime_write_clipboard_cb)(void *, const char *);
+typedef void (*ghostty_runtime_new_split_cb)(void *, ghostty_split_direction_e);
 
 typedef struct {
     void *userdata;
@@ -37,6 +38,7 @@ typedef struct {
     ghostty_runtime_set_title_cb set_title_cb;
     ghostty_runtime_read_clipboard_cb read_clipboard_cb;
     ghostty_runtime_write_clipboard_cb write_clipboard_cb;
+    ghostty_runtime_new_split_cb new_split_cb;
 } ghostty_runtime_config_s;
 
 typedef struct {
@@ -45,6 +47,11 @@ typedef struct {
     double scale_factor;
 } ghostty_surface_config_s;
 
+typedef enum {
+    GHOSTTY_SPLIT_RIGHT,
+    GHOSTTY_SPLIT_DOWN
+} ghostty_split_direction_e;
+
 typedef enum {
     GHOSTTY_MOUSE_RELEASE,
     GHOSTTY_MOUSE_PRESS,

macos/Sources/Ghostty/AppState.swift

@@ -56,7 +56,9 @@ extension Ghostty {
                 wakeup_cb: { userdata in AppState.wakeup(userdata) },
                 set_title_cb: { userdata, title in AppState.setTitle(userdata, title: title) },
                 read_clipboard_cb: { userdata in AppState.readClipboard(userdata) },
-                write_clipboard_cb: { userdata, str in AppState.writeClipboard(userdata, string: str) })
+                write_clipboard_cb: { userdata, str in AppState.writeClipboard(userdata, string: str) },
+                new_split_cb: { userdata, direction in AppState.newSplit(userdata, direction: ghostty_split_direction_e(UInt32(direction))) }
+            )
 
             // Create the ghostty app.
             guard let app = ghostty_app_new(&runtime_cfg, cfg) else {
@@ -81,6 +83,13 @@ extension Ghostty {
         
         // MARK: Ghostty Callbacks
         
+        static func newSplit(_ userdata: UnsafeMutableRawPointer?, direction: ghostty_split_direction_e) {
+            guard let surface = self.surfaceUserdata(from: userdata) else { return }
+            NotificationCenter.default.post(name: Notification.ghosttyNewSplit, object: surface, userInfo: [
+                "direction": direction,
+            ])
+        }
+        
         static func readClipboard(_ userdata: UnsafeMutableRawPointer?) -> UnsafePointer<CChar>? {
             guard let appState = self.appState(fromSurface: userdata) else { return nil }
             guard let str = NSPasteboard.general.string(forType: .string) else { return nil }
@@ -117,13 +126,18 @@ extension Ghostty {
         }
         
         /// Returns the GhosttyState from the given userdata value.
-        static func appState(fromSurface userdata: UnsafeMutableRawPointer?) -> AppState? {
+        static private func appState(fromSurface userdata: UnsafeMutableRawPointer?) -> AppState? {
             let surfaceView = Unmanaged<SurfaceView>.fromOpaque(userdata!).takeUnretainedValue()
             guard let surface = surfaceView.surface else { return nil }
             guard let app = ghostty_surface_app(surface) else { return nil }
             guard let app_ud = ghostty_app_userdata(app) else { return nil }
             return Unmanaged<AppState>.fromOpaque(app_ud).takeUnretainedValue()
         }
+        
+        /// Returns the surface view from the userdata.
+        static private func surfaceUserdata(from userdata: UnsafeMutableRawPointer?) -> SurfaceView? {
+            return Unmanaged<SurfaceView>.fromOpaque(userdata!).takeUnretainedValue()
+        }
     }
 }
 

macos/Sources/Ghostty/Ghostty.SplitView.swift

@@ -103,50 +103,51 @@ extension Ghostty {
         /// that should have it.
         private func fixFocus() {
             DispatchQueue.main.async {
+                // The view we want to focus
+                var view = state.topLeft
+                if let right = state.bottomRight { view = right }
+                
                 // If the callback runs before the surface is attached to a view
                 // then the window will be nil. We just reschedule in that case.
-                guard let window = state.topLeft.window else {
+                guard let window = view.window else {
                     self.fixFocus()
                     return
                 }
                 
-                window.makeFirstResponder(state.topLeft)
+                _ = state.topLeft.resignFirstResponder()
+                _ = state.bottomRight?.resignFirstResponder()
+                window.makeFirstResponder(view)
+            }
+        }
+        
+        private func onNewSplit(notification: SwiftUI.Notification) {
+            guard let directionAny = notification.userInfo?["direction"] else { return }
+            guard let direction = directionAny as? ghostty_split_direction_e else { return }
+            switch (direction) {
+            case GHOSTTY_SPLIT_RIGHT:
+                split(to: .horizontal)
+                
+            case GHOSTTY_SPLIT_DOWN:
+                split(to: .vertical)
+                
+            default:
+                break
             }
         }
 
         var body: some View {
             switch (state.direction) {
             case .none:
-                VStack {
+                let pub = NotificationCenter.default.publisher(for: Ghostty.Notification.ghosttyNewSplit, object: state.topLeft)
-                    HStack {
-                        Button("Split Horizontal") { split(to: .horizontal) }
-                            .keyboardShortcut("d", modifiers: .command)
-                        Button("Split Vertical") { split(to: .vertical) }
-                            .keyboardShortcut("d", modifiers: [.command, .shift])
-                    }
-                    
                 SurfaceWrapper(surfaceView: state.topLeft)
-                }
+                    .onReceive(pub) { onNewSplit(notification: $0) }
             case .horizontal:
-                VStack {
-                    HStack {
-                        Button("Close Left") { closeTopLeft() }
-                        Button("Close Right") { closeBottomRight() }
-                    }
-                    
                 SplitView(.horizontal, left: {
                     TerminalSplitChild(app, topLeft: state.topLeft)
                 }, right: {
                     TerminalSplitChild(app, topLeft: state.bottomRight!)
                 })
-                }
             case .vertical:
-                VStack {
-                    HStack {
-                        Button("Close Top") { closeTopLeft() }
-                        Button("Close Bottom") { closeBottomRight() }
-                    }
-                    
                 SplitView(.vertical, left: {
                     TerminalSplitChild(app, topLeft: state.topLeft)
                 }, right: {
@@ -155,6 +156,5 @@ extension Ghostty {
             }
         }
     }
-    }
 
 }

macos/Sources/Ghostty/Package.swift

@@ -1 +1,4 @@
-struct Ghostty {}
+struct Ghostty {
+    // All the notifications that will be emitted will be put here.
+    struct Notification {}
+}

macos/Sources/Ghostty/SurfaceView.swift

@@ -107,7 +107,7 @@ extension Ghostty {
         // We need to support being a first responder so that we can get input events
         override var acceptsFirstResponder: Bool { return true }
         
-        // I don't thikn we need this but this lets us know we should redraw our layer
+        // I don't think we need this but this lets us know we should redraw our layer
         // so we'll use that to tell ghostty to refresh.
         override var wantsUpdateLayer: Bool { return true }
         
@@ -161,6 +161,16 @@ extension Ghostty {
             ghostty_surface_set_size(surface, UInt32(scaledSize.width), UInt32(scaledSize.height))
         }
         
+        override func resignFirstResponder() -> Bool {
+            let result = super.resignFirstResponder()
+            
+            // We sometimes call this manually (see SplitView) as a way to force us to
+            // yield our focus state.
+            if (result) { focusDidChange(false) }
+            
+            return result
+        }
+        
         override func updateTrackingAreas() {
             // To update our tracking area we just recreate it all.
             trackingAreas.forEach { removeTrackingArea($0) }
@@ -494,6 +504,14 @@ extension Ghostty {
 
 }
 
+// MARK: Surface Notifications
+
+extension Ghostty.Notification {
+    /// 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")
+}
+
 // MARK: Surface Environment Keys
 
 private struct GhosttySurfaceViewKey: EnvironmentKey {

src/apprt/embedded.zig

@@ -44,6 +44,10 @@ pub const App = struct {
 
         /// Write the clipboard value.
         write_clipboard: *const fn (SurfaceUD, [*:0]const u8) callconv(.C) void,
+
+        /// Create a new split view. If the embedder doesn't support split
+        /// views then this can be null.
+        new_split: ?*const fn (SurfaceUD, input.Binding.Action.SplitDirection) callconv(.C) void = null,
     };
 
     core_app: *CoreApp,
@@ -148,6 +152,15 @@ pub const Surface = struct {
         self.core_surface.deinit();
     }
 
+    pub fn newSplit(self: *const Surface, direction: input.SplitDirection) !void {
+        const func = self.app.opts.new_split orelse {
+            log.info("runtime embedder does not support splits", .{});
+            return;
+        };
+
+        func(self.opts.userdata, direction);
+    }
+
     pub fn getContentScale(self: *const Surface) !apprt.ContentScale {
         return self.content_scale;
     }

src/input.zig

@@ -3,6 +3,7 @@ const std = @import("std");
 pub usingnamespace @import("input/mouse.zig");
 pub usingnamespace @import("input/key.zig");
 pub const Binding = @import("input/Binding.zig");
+pub const SplitDirection = Binding.Action.SplitDirection;
 
 test {
     std.testing.refAllDecls(@This());

src/input/Binding.zig

@@ -195,7 +195,9 @@ pub const Action = union(enum) {
         application: []const u8,
     };
 
-    pub const SplitDirection = enum {
+    // This is made extern (c_int) to make interop easier with our embedded
+    // runtime. The small size cost doesn't make a difference in our union.
+    pub const SplitDirection = enum(c_int) {
         right,
         down,