macOS: Added titlebar tabs

macos/Sources/Features/Terminal/TerminalController.swift

@@ -159,7 +159,7 @@ class TerminalController: NSWindowController, NSWindowDelegate,
     }
     
     override func windowDidLoad() {
-        guard let window = window else { return }
+        guard let window = window as? TerminalWindow else { return }
         
         // Setting all three of these is required for restoration to work.
         window.isRestorable = restorable
@@ -205,6 +205,32 @@ class TerminalController: NSWindowController, NSWindowDelegate,
         // when cascading.
         window.center()
 		
+		// Set the background color of the window
+		window.backgroundColor = NSColor(self.ghostty.config.backgroundColor)
+		
+		// Handle titlebar tabs config option
+		if (self.ghostty.config.macosTitlebarTabs) {
+			window.titlebarTabs = true
+			window.titlebarAppearsTransparent = true
+			
+			// We use the toolbar to anchor our tab bar positions in the titlebar,
+			// so we make sure it's the right size/position, and exists.
+			window.toolbarStyle = .unifiedCompact
+			if (window.toolbar == nil) {
+				window.toolbar = NSToolbar(identifier: "Toolbar")
+			}
+		} else {
+			window.titlebarTabs = false
+			window.titlebarAppearsTransparent = false
+			
+			// "expanded" places the toolbar below the titlebar, so setting this style and
+			// removing the toolbar ensures that the titlebar will be the default height.
+			window.toolbarStyle = .expanded
+			if (window.toolbar != nil) {
+				window.toolbar = nil
+			}
+		}
+		
         // Initialize our content view to the SwiftUI root
         window.contentView = NSHostingView(rootView: TerminalView(
             ghostty: self.ghostty,
@@ -293,6 +319,10 @@ class TerminalController: NSWindowController, NSWindowDelegate,
     
     func windowDidBecomeKey(_ notification: Notification) {
         self.relabelTabs()
+		
+		// Fix for titlebar tabs, see comment on implementation of fixUntabbedWindow for details.
+		guard let window = window as? TerminalWindow else { return }
+		window.fixUntabbedWindow()
     }
     
     // Called when the window will be encoded. We handle the data encoding here in the

macos/Sources/Features/Terminal/TerminalWindow.swift

@@ -1,8 +1,189 @@
 import Cocoa
 
+// Passes mouseDown events from this view to window.performDrag so that you can drag the window by it.
+class WindowDragView: NSView {
+	override public func mouseDown(with event: NSEvent) {
+		// Drag the window for single left clicks, double clicks should bypass the drag handle.
+		if (event.type == .leftMouseDown && event.clickCount == 1) {
+			window?.performDrag(with: event)
+			NSCursor.closedHand.set()
+		} else {
+			super.mouseDown(with: event)
+		}
+	}
+	
+	override public func mouseEntered(with event: NSEvent) {
+		super.mouseEntered(with: event)
+		window?.disableCursorRects()
+		NSCursor.openHand.set()
+	}
+	
+	override func mouseExited(with event: NSEvent) {
+		super.mouseExited(with: event)
+		window?.enableCursorRects()
+		NSCursor.arrow.set()
+	}
+	
+	override func resetCursorRects() {
+		addCursorRect(bounds, cursor: .openHand)
+	}
+}
+
+let TabBarController = NSUserInterfaceItemIdentifier("_tabBarController")
+
 class TerminalWindow: NSWindow {
     // Both of these must be true for windows without decorations to be able to
     // still become key/main and receive events.
     override var canBecomeKey: Bool { return true }
     override var canBecomeMain: Bool { return true }
+	
+	// Used by the window controller to enable/disable titlebar tabs.
+	public var titlebarTabs = false
+	
+	override func addTitlebarAccessoryViewController(_ childViewController: NSTitlebarAccessoryViewController) {
+		var isTabBar = false
+		if (self.titlebarTabs && (
+			childViewController.layoutAttribute == .bottom ||
+			childViewController.identifier == TabBarController)
+		) {
+			// Ensure it has the right layoutAttribute
+			childViewController.layoutAttribute = .right
+			// Hide the title text if the tab bar is showing.
+			titleVisibility = .hidden
+			// Mark the controller for future reference (it gets re-used sometimes)
+			childViewController.identifier = TabBarController
+			isTabBar = true
+		}
+		super.addTitlebarAccessoryViewController(childViewController)
+		if (isTabBar) {
+			pushTabsToTitlebar(childViewController)
+		}
+	}
+	
+	override func removeTitlebarAccessoryViewController(at index: Int) {
+		let childViewController = titlebarAccessoryViewControllers[index]
+		super.removeTitlebarAccessoryViewController(at: index)
+		if (childViewController.layoutAttribute == .right) {
+			hideCustomTabBarViews()
+		}
+	}
+	
+	// This is a hack - provide a function for the window controller to call in windowDidBecomeKey
+	// to check if it's no longer tabbed and fix its appearing if so. This is required because the
+	// removeTitlebarAccessoryViewControlle hook does not catch the creation of a new window by
+	// "tearing off" a tab from a tabbed window.
+	public func fixUntabbedWindow() {
+		if let tabGroup = self.tabGroup, tabGroup.windows.count < 2 {
+			hideCustomTabBarViews()
+		}
+	}
+	
+	private var windowButtonsBackdrop: NSView? = nil
+	
+	private func addWindowButtonsBackdrop(titlebarView: NSView, toolbarView: NSView) {
+		guard windowButtonsBackdrop == nil else { return }
+		
+		windowButtonsBackdrop = NSView()
+		
+		guard let windowButtonsBackdrop = windowButtonsBackdrop else { return }
+		
+		windowButtonsBackdrop.identifier = NSUserInterfaceItemIdentifier("_windowButtonsBackdrop")
+		titlebarView.addSubview(windowButtonsBackdrop)
+		windowButtonsBackdrop.translatesAutoresizingMaskIntoConstraints = false
+		windowButtonsBackdrop.leftAnchor.constraint(equalTo: toolbarView.leftAnchor).isActive = true
+		windowButtonsBackdrop.rightAnchor.constraint(equalTo: toolbarView.leftAnchor, constant: 80).isActive = true
+		windowButtonsBackdrop.topAnchor.constraint(equalTo: toolbarView.topAnchor).isActive = true
+		windowButtonsBackdrop.heightAnchor.constraint(equalTo: toolbarView.heightAnchor).isActive = true
+		windowButtonsBackdrop.wantsLayer = true
+		windowButtonsBackdrop.layer?.backgroundColor = CGColor(genericGrayGamma2_2Gray: 0.0, alpha: 0.45)
+		
+		let topBorder = NSView()
+		windowButtonsBackdrop.addSubview(topBorder)
+		topBorder.translatesAutoresizingMaskIntoConstraints = false
+		topBorder.leftAnchor.constraint(equalTo: windowButtonsBackdrop.leftAnchor).isActive = true
+		topBorder.rightAnchor.constraint(equalTo: windowButtonsBackdrop.rightAnchor).isActive = true
+		topBorder.topAnchor.constraint(equalTo: windowButtonsBackdrop.topAnchor).isActive = true
+		topBorder.bottomAnchor.constraint(equalTo: windowButtonsBackdrop.topAnchor, constant: 1).isActive = true
+		topBorder.wantsLayer = true
+		topBorder.layer?.backgroundColor = CGColor(genericGrayGamma2_2Gray: 0.0, alpha: 0.85)
+	}
+	
+	var windowDragHandle: WindowDragView? = nil
+	
+	private func addWindowDragHandle(titlebarView: NSView, toolbarView: NSView) {
+		guard windowDragHandle == nil else { return }
+		
+		windowDragHandle = WindowDragView()
+		
+		guard let windowDragHandle = windowDragHandle else { return }
+		
+		windowDragHandle.identifier = NSUserInterfaceItemIdentifier("_windowDragHandle")
+		titlebarView.superview?.addSubview(windowDragHandle)
+		windowDragHandle.translatesAutoresizingMaskIntoConstraints = false
+		windowDragHandle.leftAnchor.constraint(equalTo: toolbarView.leftAnchor).isActive = true
+		windowDragHandle.rightAnchor.constraint(equalTo: toolbarView.rightAnchor).isActive = true
+		windowDragHandle.topAnchor.constraint(equalTo: toolbarView.topAnchor).isActive = true
+		windowDragHandle.bottomAnchor.constraint(equalTo: toolbarView.topAnchor, constant: 12).isActive = true
+	}
+	
+	// To be called immediately after the tab bar is disabled.
+	public func hideCustomTabBarViews() {
+		// Hide the window buttons backdrop.
+		windowButtonsBackdrop?.isHidden = true
+		// Hide the window drag handle.
+		windowDragHandle?.isHidden = true
+		// Enable the window title text.
+		titleVisibility = .visible
+	}
+	
+	private func pushTabsToTitlebar(_ tabBarController: NSTitlebarAccessoryViewController) {
+		let accessoryView = tabBarController.view
+		guard let accessoryClipView = accessoryView.superview else { return }
+		guard let titlebarView = accessoryClipView.superview else { return }
+		
+		guard titlebarView.className == "NSTitlebarView" else { return }
+		
+		guard let toolbarView = titlebarView.subviews.first(where: {
+			$0.className == "NSToolbarView"
+		}) else { return }
+		
+		addWindowButtonsBackdrop(titlebarView: titlebarView, toolbarView: toolbarView)
+		windowButtonsBackdrop?.isHidden = false
+		guard let windowButtonsBackdrop = windowButtonsBackdrop else { return }
+		
+		addWindowDragHandle(titlebarView: titlebarView, toolbarView: toolbarView)
+		windowDragHandle?.isHidden = false
+		
+		accessoryClipView.translatesAutoresizingMaskIntoConstraints = false
+		accessoryClipView.leftAnchor.constraint(equalTo: windowButtonsBackdrop.rightAnchor).isActive = true
+		accessoryClipView.rightAnchor.constraint(equalTo: toolbarView.rightAnchor).isActive = true
+		accessoryClipView.topAnchor.constraint(equalTo: toolbarView.topAnchor).isActive = true
+		accessoryClipView.heightAnchor.constraint(equalTo: toolbarView.heightAnchor).isActive = true
+		accessoryClipView.needsLayout = true
+		
+		accessoryView.translatesAutoresizingMaskIntoConstraints = false
+		accessoryView.leftAnchor.constraint(equalTo: accessoryClipView.leftAnchor).isActive = true
+		accessoryView.rightAnchor.constraint(equalTo: accessoryClipView.rightAnchor).isActive = true
+		accessoryView.topAnchor.constraint(equalTo: accessoryClipView.topAnchor).isActive = true
+		accessoryView.heightAnchor.constraint(equalTo: accessoryClipView.heightAnchor).isActive = true
+		accessoryView.needsLayout = true
+		
+		// This is a horrible hack. During the transition while things are resizing to make room for
+		// new tabs or expand existing tabs to fill the empty space after one is closed, the centering
+		// of the tab titles can't be properly calculated, so we wait for 0.2 seconds and then mark
+		// the entire view hierarchy for the tab bar as dirty to fix the positioning...
+		DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) {
+			self.markHierarchyForLayout(accessoryView)
+		}
+	}
+	
+	private func markHierarchyForLayout(_ view: NSView) {
+		view.needsUpdateConstraints = true
+		view.needsLayout = true
+		view.needsDisplay = true
+		view.setNeedsDisplay(view.bounds)
+		for subview in view.subviews {
+			markHierarchyForLayout(subview)
+		}
+	}
 }

macos/Sources/Ghostty/Ghostty.Config.swift

@@ -198,6 +198,14 @@ extension Ghostty {
             return v
         }
 		
+		var macosTitlebarTabs: Bool {
+			guard let config = self.config else { return false }
+			var v = false;
+			let key = "macos-titlebar-tabs"
+			_ = ghostty_config_get(config, &v, key, UInt(key.count))
+			return v
+		}
+        
         var backgroundColor: Color {
             var rgb: UInt32 = 0
             let bg_key = "background"

src/config/Config.zig

@@ -891,6 +891,13 @@ keybind: Keybinds = .{},
 ///   * `false` - Use native macOS fullscreeen
 @"macos-non-native-fullscreen": NonNativeFullscreen = .false,
 
+/// If `true`, places the tab bar in the titlebar for tabbed windows.
+///
+/// This option intercepts the native tab bar view from macOS and forces it to use
+/// different positioning. Because of this, it might be buggy or break entirely if
+/// macOS changes the way its native tab bar view is constructed or managed.
+@"macos-titlebar-tabs": bool = false,
+
 /// If `true`, the *Option* key will be treated as *Alt*. This makes terminal
 /// sequences expecting *Alt* to work properly, but will break Unicode input
 /// sequences on macOS if you use them via the *Alt* key. You may set this to