macos: set window resizeIncrements when cell size changes

The resizeIncrements property is only modified when the cell size of the
focused window changes. If two splits have the same cell size then the
property is not modified when focusing between the two splits.

include/ghostty.h

@@ -337,6 +337,7 @@ typedef void (*ghostty_runtime_goto_tab_cb)(void *, int32_t);
 typedef void (*ghostty_runtime_toggle_fullscreen_cb)(void *, ghostty_non_native_fullscreen_e);
 typedef void (*ghostty_runtime_set_initial_window_size_cb)(void *, uint32_t, uint32_t);
 typedef void (*ghostty_runtime_render_inspector_cb)(void *);
+typedef void (*ghostty_runtime_set_cell_size_cb)(void *, uint32_t, uint32_t);
 
 typedef struct {
     void *userdata;
@@ -359,6 +360,7 @@ typedef struct {
     ghostty_runtime_toggle_fullscreen_cb toggle_fullscreen_cb;
     ghostty_runtime_set_initial_window_size_cb set_initial_window_size_cb;
     ghostty_runtime_render_inspector_cb render_inspector_cb;
+    ghostty_runtime_set_cell_size_cb set_cell_size_cb;
 } ghostty_runtime_config_s;
 
 //-------------------------------------------------------------------

macos/Ghostty.xcodeproj/project.pbxproj

@@ -38,7 +38,6 @@
 		A5CEAFFF29C2410700646FDA /* Backport.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5CEAFFE29C2410700646FDA /* Backport.swift */; };
 		A5FEB3002ABB69450068369E /* main.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5FEB2FF2ABB69450068369E /* main.swift */; };
 		A5FECBD729D1FC3900022361 /* PrimaryView.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5FECBD629D1FC3900022361 /* PrimaryView.swift */; };
-		A5FECBD929D2010400022361 /* WindowAccessor.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5FECBD829D2010400022361 /* WindowAccessor.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -76,7 +75,6 @@
 		A5D495A1299BEC7E00DD1313 /* GhosttyKit.xcframework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcframework; path = GhosttyKit.xcframework; sourceTree = "<group>"; };
 		A5FEB2FF2ABB69450068369E /* main.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = main.swift; sourceTree = "<group>"; };
 		A5FECBD629D1FC3900022361 /* PrimaryView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PrimaryView.swift; sourceTree = "<group>"; };
-		A5FECBD829D2010400022361 /* WindowAccessor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WindowAccessor.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -120,7 +118,6 @@
 				A5CEAFFE29C2410700646FDA /* Backport.swift */,
 				8503D7C62A549C66006CFF3D /* FullScreenHandler.swift */,
 				A59FB5D02AE0DEA7009128F3 /* MetalView.swift */,
-				A5FECBD829D2010400022361 /* WindowAccessor.swift */,
 				A5CEAFDA29B8005900646FDA /* SplitView */,
 			);
 			path = Helpers;
@@ -313,7 +310,6 @@
 				A5CDF1932AAF9E0800513312 /* ConfigurationErrorsController.swift in Sources */,
 				A59FB5D12AE0DEA7009128F3 /* MetalView.swift in Sources */,
 				A55685E029A03A9F004303CE /* AppError.swift in Sources */,
-				A5FECBD929D2010400022361 /* WindowAccessor.swift in Sources */,
 				A535B9DA299C569B0017E2E4 /* ErrorView.swift in Sources */,
 				85102A1C2A6E32890084AB3E /* PrimaryWindowController.swift in Sources */,
 				A5CEAFFF29C2410700646FDA /* Backport.swift in Sources */,

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

@@ -16,7 +16,7 @@ struct PrimaryView: View {
     
     // We need access to our window to know if we're the key window to determine
     // if we show the quit confirmation or not.
-    @State private var window: NSWindow?
+    var window: NSWindow
     
     // This handles non-native fullscreen
     @State private var fullScreen = FullScreenHandler()
@@ -27,6 +27,7 @@ struct PrimaryView: View {
     @FocusedValue(\.ghosttySurfaceView) private var focusedSurface
     @FocusedValue(\.ghosttySurfaceTitle) private var surfaceTitle
     @FocusedValue(\.ghosttySurfaceZoomed) private var zoomedSplit
+    @FocusedValue(\.ghosttySurfaceCellSize) private var cellSize
     
     // The title for our window
     private var title: String {
@@ -68,7 +69,6 @@ struct PrimaryView: View {
                 Ghostty.TerminalSplit(onClose: Self.closeWindow, baseConfig: self.baseConfig)
                     .ghosttyApp(ghostty.app!)
                     .ghosttyConfig(ghostty.config!)
-                    .background(WindowAccessor(window: $window))
                     .onReceive(gotoTab) { onGotoTab(notification: $0) }
                     .onReceive(toggleFullscreen) { onToggleFullscreen(notification: $0) }
                     .focused($focused)
@@ -79,8 +79,11 @@ struct PrimaryView: View {
                     .onChange(of: title) { newValue in
                         // We need to handle this manually because we are using AppKit lifecycle
                         // so navigationTitle no longer works.
-                        guard let window = self.window else { return }
+                        self.window.title = newValue
-                        window.title = newValue
+                    }
+                    .onChange(of: cellSize) { newValue in
+                        guard let size = newValue else { return }
+                        self.window.contentResizeIncrements = size
                     }
             }
         }
@@ -95,8 +98,7 @@ struct PrimaryView: View {
         // Notification center indiscriminately sends to every subscriber (makes sense)
         // but we only want to process this once. In order to process it once lets only
         // handle it if we're the focused window.
-        guard let window = self.window else { return }
+        guard self.window.isKeyWindow else { return }
-        guard window.isKeyWindow else { return }
         
         // Get the tab index from the notification
         guard let tabIndexAny = notification.userInfo?[Ghostty.Notification.GotoTabKey] else { return }
@@ -135,8 +137,7 @@ struct PrimaryView: View {
         // Just like in `onGotoTab`, we might receive this multiple times. But
         // it's fine, because `toggleFullscreen` should only apply to the
         // currently focused window.
-        guard let window = self.window else { return }
+        guard self.window.isKeyWindow else { return }
-        guard window.isKeyWindow else { return }
 
         // Check whether we use non-native fullscreen
         guard let useNonNativeFullscreenAny = notification.userInfo?[Ghostty.Notification.NonNativeFullscreenKey] else { return }

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

@@ -41,7 +41,8 @@ class PrimaryWindow: NSWindow {
             ghostty: ghostty,
             appDelegate: appDelegate,
             focusedSurfaceWrapper: window.focusedSurfaceWrapper,
-            baseConfig: baseConfig
+            baseConfig: baseConfig,
+            window: window
         ))
         
         // We do want to cascade when new windows are created

macos/Sources/Ghostty/AppState.swift

@@ -143,7 +143,8 @@ extension Ghostty {
                 goto_tab_cb: { userdata, n in AppState.gotoTab(userdata, n: n) },
                 toggle_fullscreen_cb: { userdata, nonNativeFullscreen in AppState.toggleFullscreen(userdata, nonNativeFullscreen: nonNativeFullscreen) },
                 set_initial_window_size_cb: { userdata, width, height in AppState.setInitialWindowSize(userdata, width: width, height: height) },
-                render_inspector_cb: { userdata in AppState.renderInspector(userdata) }
+                render_inspector_cb: { userdata in AppState.renderInspector(userdata) },
+                set_cell_size_cb: { userdata, width, height in AppState.setCellSize(userdata, width: width, height: height) }
             )
 
             // Create the ghostty app.
@@ -468,6 +469,12 @@ extension Ghostty {
             surfaceView.initialSize = NSMakeSize(Double(width), Double(height))
         }
 
+        static func setCellSize(_ userdata: UnsafeMutableRawPointer?, width: UInt32, height: UInt32) {
+            guard let surfaceView = self.surfaceUserdata(from: userdata) else { return }
+            let backingSize = NSSize(width: Double(width), height: Double(height))
+            surfaceView.cellSize = surfaceView.convertFromBacking(backingSize)
+        }
+
         static func newTab(_ userdata: UnsafeMutableRawPointer?, config: ghostty_surface_config_s) {
             guard let surface = self.surfaceUserdata(from: userdata) else { return }
             

macos/Sources/Ghostty/SurfaceView.swift

@@ -78,6 +78,7 @@ extension Ghostty {
                         .focused($surfaceFocus)
                         .focusedValue(\.ghosttySurfaceTitle, surfaceView.title)
                         .focusedValue(\.ghosttySurfaceView, surfaceView)
+                        .focusedValue(\.ghosttySurfaceCellSize, surfaceView.cellSize)
                         .onReceive(pubBecomeKey) { notification in
                             guard let window = notification.object as? NSWindow else { return }
                             guard let surfaceWindow = surfaceView.window else { return }
@@ -240,7 +241,9 @@ extension Ghostty {
         // changed with escape codes. This is public because the callbacks go
         // to the app level and it is set from there.
         @Published var title: String = "👻"
-        
+
+        @Published var cellSize: NSSize = .init()
+
         // An initial size to request for a window. This will only affect
         // then the view is moved to a new window.
         var initialSize: NSSize? = nil
@@ -930,3 +933,14 @@ extension FocusedValues {
         typealias Value = Bool
     }
 }
+
+extension FocusedValues {
+    var ghosttySurfaceCellSize: NSSize? {
+        get { self[FocusedGhosttySurfaceCellSize.self] }
+        set { self[FocusedGhosttySurfaceCellSize.self] = newValue }
+    }
+
+    struct FocusedGhosttySurfaceCellSize: FocusedValueKey {
+        typealias Value = NSSize
+    }
+}

macos/Sources/Helpers/WindowAccessor.swift

@@ -1,16 +0,0 @@
-import SwiftUI
-
-/// Allows accessing the window that this view is a part of.
-struct WindowAccessor: NSViewRepresentable {
-    @Binding var window: NSWindow?
-    
-    func makeNSView(context: Context) -> NSView {
-        let view = NSView()
-        DispatchQueue.main.async {
-            self.window = view.window
-        }
-        return view
-    }
-    
-    func updateNSView(_ nsView: NSView, context: Context) {}
-}

src/Surface.zig

@@ -460,6 +460,9 @@ pub fn init(
         .config = try DerivedConfig.init(alloc, config),
     };
 
+    // Report initial cell size on surface creation
+    try rt_surface.setCellSize(cell_size.width, cell_size.height);
+
     // Set a minimum size that is cols=10 h=4. This matches Mac's Terminal.app
     // but is otherwise somewhat arbitrary.
     try rt_surface.setSizeLimits(.{
@@ -896,6 +899,9 @@ fn setCellSize(self: *Surface, size: renderer.CellSize) !void {
         },
     }, .{ .forever = {} });
     self.io_thread.wakeup.notify() catch {};
+
+    // Notify the window
+    try self.rt_surface.setCellSize(size.width, size.height);
 }
 
 /// Change the font size.

src/apprt/embedded.zig

@@ -98,6 +98,9 @@ pub const App = struct {
 
         /// Render the inspector for the given surface.
         render_inspector: ?*const fn (SurfaceUD) callconv(.C) void = null,
+
+        /// Called when the cell size changes.
+        set_cell_size: ?*const fn (SurfaceUD, u32, u32) callconv(.C) void = null,
     };
 
     /// Special values for the goto_tab callback.
@@ -818,6 +821,15 @@ pub const Surface = struct {
         func(self.opts.userdata);
     }
 
+    pub fn setCellSize(self: *const Surface, width: u32, height: u32) !void {
+        const func = self.app.opts.set_cell_size orelse {
+            log.info("runtime embedder does not support set_cell_size", .{});
+            return;
+        };
+
+        func(self.opts.userdata, width, height);
+    }
+
     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;

src/apprt/glfw.zig

@@ -461,6 +461,13 @@ pub const Surface = struct {
         self.window.setSize(.{ .width = width, .height = height });
     }
 
+    /// Set the cell size. Unused by GLFW.
+    pub fn setCellSize(self: *const Surface, width: u32, height: u32) !void {
+        _ = self;
+        _ = width;
+        _ = height;
+    }
+
     /// Set the size limits of the window.
     /// Note: this interface is not good, we should redo it if we plan
     /// to use this more. i.e. you can't set max width but no max height,

src/apprt/gtk/Surface.zig

@@ -374,6 +374,12 @@ pub fn setInitialWindowSize(self: *const Surface, width: u32, height: u32) !void
     );
 }
 
+pub fn setCellSize(self: *const Surface, width: u32, height: u32) !void {
+    _ = self;
+    _ = width;
+    _ = height;
+}
+
 pub fn setSizeLimits(self: *Surface, min: apprt.SurfaceSize, max_: ?apprt.SurfaceSize) !void {
     _ = self;
     _ = min;