macos: run as LSUIElement menubar app with NSStatusItem

Ship Lan Mouse on macOS as an accessory app (no Dock icon, no main
window on launch) with a status-bar item for show/quit. Closing the
window hides it instead of quitting so the menu bar stays the primary
surface.

- build-aux/macos-lsui-element.plist: LSUIElement=true plus
  NSInputMonitoringUsageDescription and NSAppleEventsUsageDescription
  (merged into Info.plist via cargo-bundle's osx_info_plist_exts).
- lan-mouse-gtk/src/macos_status_item.rs: NSStatusItem setup via raw
  objc_msgSend FFI. Loads a bundled 22pt PNG as a template image so
  it auto-tints for light/dark menu bars.
- scripts/makeicns.sh: emit Contents/Resources/menubar-template.png
  from the existing SVG.
- scripts/copy-macos-dylib.sh: flatten cargo-bundle's preserved
  target/ subdir under Resources so NSBundle pathForResource: finds
  the template image.
- lan-mouse-gtk/src/lib.rs: register the new modules, set up a
  Cmd+Q-wired quit action, configure bundle env vars (schemas,
  XDG_DATA_DIRS, GTK_DATA_PREFIX) when running from inside the .app,
  and filter the known upstream Gtk theme-parser warning spam.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -1682,6 +1682,8 @@ dependencies = [
  "ashpd",
  "async-trait",
  "bitflags 2.11.0",
+ "core-foundation",
+ "core-foundation-sys",
  "core-graphics",
  "futures",
  "input-event",

Cargo.toml

@@ -96,3 +96,5 @@ rdp_emulation = ["input-emulation/remote_desktop_portal"]
 name = "Lan Mouse"
 icon = ["target/icon.icns"]
 identifier = "de.feschber.LanMouse"
+osx_info_plist_exts = ["build-aux/macos-lsui-element.plist"]
+resources = ["target/menubar-template.png"]

README.md

@@ -105,6 +105,7 @@ dnf install lan-mouse
 - Unzip it
 - Remove the quarantine with `xattr -rd com.apple.quarantine "Lan Mouse.app"`
 - Launch the app
+- Use the menu bar item to open the settings window or quit Lan Mouse. Bundled macOS builds run as a menu bar app and do not keep a Dock icon visible.
 - Grant accessibility permissions in System Preferences
 
 </details>
@@ -475,4 +476,4 @@ The following sections detail the emulation and capture backends provided by lan
 - `libei`: This backend uses [libei](https://gitlab.freedesktop.org/libinput/libei) and is supported by GNOME >= 45 or KDE Plasma >= 6.1.
 - `windows`: Backend for input capture on Windows.
 - `macos`: Backend for input capture on MacOS.
-- `x11`: TODO (not yet supported)
+- `x11`: TODO (not yet supported)

build-aux/macos-lsui-element.plist

@@ -0,0 +1,6 @@
+  <key>LSUIElement</key>
+  <true/>
+  <key>NSInputMonitoringUsageDescription</key>
+  <string>Lan Mouse needs Input Monitoring access to capture keyboard and mouse input and forward it to remote machines on your network.</string>
+  <key>NSAppleEventsUsageDescription</key>
+  <string>Lan Mouse uses Apple Events to deliver synthesized keyboard and mouse events to the system.</string>

lan-mouse-gtk/src/lib.rs

@@ -4,6 +4,10 @@ mod client_row;
 mod fingerprint_window;
 mod key_object;
 mod key_row;
+#[cfg(target_os = "macos")]
+mod macos_privacy;
+#[cfg(target_os = "macos")]
+mod macos_status_item;
 mod window;
 
 use std::{env, process, str};
@@ -47,6 +51,12 @@ pub fn run() -> Result<(), GtkError> {
 }
 
 fn gtk_main() -> glib::ExitCode {
+    #[cfg(target_os = "macos")]
+    {
+        configure_macos_bundle_environment();
+        install_macos_gtk_log_filter();
+    }
+
     gio::resources_register_include!("lan-mouse.gresource").expect("Failed to register resources.");
 
     let app = Application::builder()
@@ -64,6 +74,64 @@ fn gtk_main() -> glib::ExitCode {
     app.run_with_args(&args)
 }
 
+#[cfg(target_os = "macos")]
+fn install_macos_gtk_log_filter() {
+    glib::log_set_writer_func(|level, fields| {
+        if level == glib::LogLevel::Warning && is_gtk_theme_parser_warning(fields) {
+            return glib::LogWriterOutput::Handled;
+        }
+
+        glib::log_writer_default(level, fields)
+    });
+}
+
+#[cfg(target_os = "macos")]
+fn is_gtk_theme_parser_warning(fields: &[glib::LogField<'_>]) -> bool {
+    let mut domain = None;
+    let mut message = None;
+
+    for field in fields {
+        match field.key() {
+            "GLIB_DOMAIN" => domain = field.value_str(),
+            "MESSAGE" => message = field.value_str(),
+            _ => {}
+        }
+    }
+
+    domain == Some("Gtk")
+        && message.is_some_and(|message| message.starts_with("Theme parser warning: gtk.css:"))
+}
+
+#[cfg(target_os = "macos")]
+fn configure_macos_bundle_environment() {
+    let Ok(exe) = env::current_exe() else {
+        return;
+    };
+    let Some(contents) = exe
+        .parent()
+        .and_then(|dir| dir.parent())
+        .map(std::path::Path::to_owned)
+    else {
+        return;
+    };
+
+    let share = contents.join("Resources").join("share");
+    if !share.exists() {
+        return;
+    }
+
+    let schemas = share.join("glib-2.0").join("schemas");
+    if schemas.exists() {
+        env::set_var("GSETTINGS_SCHEMA_DIR", schemas);
+    }
+
+    env::set_var("XDG_DATA_DIRS", &share);
+    env::set_var(
+        "GTK_DATA_PREFIX",
+        contents.join("Resources").to_string_lossy().as_ref(),
+    );
+}
+
 fn load_icons() {
     let display = &Display::default().expect("Could not connect to a display.");
     let icon_theme = IconTheme::for_display(display);
@@ -123,6 +191,16 @@ fn build_ui(app: &Application) {
     });
 
     let window = Window::new(app, frontend_tx);
+    #[cfg(target_os = "macos")]
+    {
+        window.connect_close_request(|window| {
+            window.set_visible(false);
+            glib::Propagation::Stop
+        });
+        macos_status_item::setup(app, &window);
+        // First-launch TCC prompts. No-op when already granted.
+        macos_privacy::fire_initial_prompts();
+    }
 
     glib::spawn_future_local(clone!(
         #[weak]
@@ -171,5 +249,6 @@ fn build_ui(app: &Application) {
         }
     ));
 
+    #[cfg(not(target_os = "macos"))]
     window.present();
 }

lan-mouse-gtk/src/macos_status_item.rs

@@ -0,0 +1,283 @@
+#![allow(clashing_extern_declarations)]
+
+use std::{
+    cell::RefCell,
+    ffi::{CStr, CString, c_char, c_double, c_void},
+    sync::OnceLock,
+};
+
+use adw::prelude::*;
+use gtk::{gio, glib};
+
+use crate::window::Window;
+
+type Id = *mut c_void;
+type Class = *mut c_void;
+type Sel = *mut c_void;
+type Bool = i8;
+
+struct StatusItem {
+    app: glib::WeakRef<adw::Application>,
+    window: glib::WeakRef<Window>,
+    _hold: gio::ApplicationHoldGuard,
+    _delegate: Id,
+    _status_item: Id,
+}
+
+thread_local! {
+    static STATUS_ITEM: RefCell<Option<StatusItem>> = const { RefCell::new(None) };
+}
+
+pub fn setup(app: &adw::Application, window: &Window) {
+    log::debug!("macos_status_item::setup entered");
+    STATUS_ITEM.with(|item| {
+        let already_initialized = item.borrow().is_some();
+        if already_initialized {
+            let mut cell = item.borrow_mut();
+            if let Some(existing) = cell.as_mut() {
+                existing.app.set(Some(app));
+                existing.window.set(Some(window));
+            }
+            return;
+        }
+
+        unsafe {
+            let hold = app.hold();
+
+            let ns_app = msg_send_id(class(c"NSApplication"), sel(c"sharedApplication"));
+            assert!(!ns_app.is_null(), "NSApplication sharedApplication returned null");
+            msg_send_bool_usize(ns_app, sel(c"setActivationPolicy:"), 1);
+
+            let delegate = new_delegate();
+            let menu = menu(&[
+                menu_item(c"Open Lan Mouse", c"showLanMouse:"),
+                separator_item(),
+                menu_item(c"Quit Lan Mouse", c"quitLanMouse:"),
+            ]);
+
+            let status_bar = msg_send_id(class(c"NSStatusBar"), sel(c"systemStatusBar"));
+            assert!(!status_bar.is_null(), "NSStatusBar systemStatusBar returned null");
+            let status_item = msg_send_id_f64(status_bar, sel(c"statusItemWithLength:"), -1.0);
+            assert!(!status_item.is_null(), "statusItemWithLength returned null");
+            // Retain so the status item survives autorelease pool drain.
+            let status_item = msg_send_id(status_item, sel(c"retain"));
+
+            let button = msg_send_id(status_item, sel(c"button"));
+            assert!(!button.is_null(), "NSStatusItem.button was null");
+            set_button_image(button);
+            msg_send_void_id(button, sel(c"setToolTip:"), nsstring(c"Lan Mouse"));
+            msg_send_void_id(status_item, sel(c"setMenu:"), menu);
+
+            for item in menu_items(menu) {
+                msg_send_void_id(item, sel(c"setTarget:"), delegate);
+            }
+
+            log::debug!("macos_status_item ready at {:p}", status_item);
+
+            item.replace(Some(StatusItem {
+                app: app.downgrade(),
+                window: window.downgrade(),
+                _hold: hold,
+                _delegate: delegate,
+                _status_item: status_item,
+            }));
+        }
+    });
+}
+
+// Prefer a pre-rendered template PNG (black silhouette with alpha) so macOS
+// auto-tints the glyph to match the menu bar in light and dark modes.
+// Falls back to the full-color icns, then to "LM" text.
+unsafe fn set_button_image(button: Id) {
+    if let Some(image) = load_menubar_template() {
+        msg_send_void_bool(image, sel(c"setTemplate:"), 1);
+        msg_send_void_id(button, sel(c"setImage:"), image);
+        return;
+    }
+    if let Some(image) = load_app_icon() {
+        msg_send_void_id(button, sel(c"setImage:"), image);
+        return;
+    }
+    log::warn!("no menu bar image available; falling back to text title");
+    msg_send_void_id(button, sel(c"setTitle:"), nsstring(c"LM"));
+}
+
+unsafe fn load_menubar_template() -> Option<Id> {
+    load_resource_image(c"menubar-template", c"png", MENUBAR_ICON_SIZE)
+}
+
+unsafe fn load_app_icon() -> Option<Id> {
+    load_resource_image(c"icon", c"icns", MENUBAR_ICON_SIZE)
+}
+
+unsafe fn load_resource_image(name: &CStr, ext: &CStr, size_pt: c_double) -> Option<Id> {
+    let bundle = msg_send_id(class(c"NSBundle"), sel(c"mainBundle"));
+    if bundle.is_null() {
+        return None;
+    }
+    let path = msg_send_id_id_id(
+        bundle,
+        sel(c"pathForResource:ofType:"),
+        nsstring(name),
+        nsstring(ext),
+    );
+    if path.is_null() {
+        return None;
+    }
+    let image = msg_send_id_id(
+        msg_send_id(class(c"NSImage"), sel(c"alloc")),
+        sel(c"initWithContentsOfFile:"),
+        path,
+    );
+    if image.is_null() {
+        return None;
+    }
+    // Render at menu bar height; 22pt is the full status bar icon height.
+    msg_send_void_size(image, sel(c"setSize:"), size_pt, size_pt);
+    Some(image)
+}
+
+const MENUBAR_ICON_SIZE: c_double = 22.0;
+
+unsafe fn menu(items: &[Id]) -> Id {
+    let menu = msg_send_id(msg_send_id(class(c"NSMenu"), sel(c"alloc")), sel(c"init"));
+    for item in items {
+        msg_send_void_id(menu, sel(c"addItem:"), *item);
+    }
+    menu
+}
+
+unsafe fn menu_item(title: &CStr, action: &CStr) -> Id {
+    msg_send_id_id_sel_id(
+        msg_send_id(class(c"NSMenuItem"), sel(c"alloc")),
+        sel(c"initWithTitle:action:keyEquivalent:"),
+        nsstring(title),
+        sel(action),
+        nsstring(c""),
+    )
+}
+
+unsafe fn separator_item() -> Id {
+    msg_send_id(class(c"NSMenuItem"), sel(c"separatorItem"))
+}
+
+unsafe fn menu_items(menu: Id) -> Vec<Id> {
+    let count = msg_send_usize(menu, sel(c"numberOfItems"));
+    (0..count)
+        .map(|idx| msg_send_id_usize(menu, sel(c"itemAtIndex:"), idx))
+        .collect()
+}
+
+unsafe fn new_delegate() -> Id {
+    let class = delegate_class();
+    msg_send_id(msg_send_id(class, sel(c"alloc")), sel(c"init"))
+}
+
+fn delegate_class() -> Class {
+    static CLASS: OnceLock<usize> = OnceLock::new();
+
+    *CLASS.get_or_init(|| unsafe {
+        let superclass = class(c"NSObject");
+        let class_name = CString::new("LanMouseStatusItemDelegate").unwrap();
+        let class = objc_allocateClassPair(superclass, class_name.as_ptr(), 0);
+        assert!(!class.is_null(), "failed to allocate status item delegate");
+
+        class_addMethod(
+            class,
+            sel(c"showLanMouse:"),
+            show_lan_mouse as *const c_void,
+            c"v@:@".as_ptr(),
+        );
+        class_addMethod(
+            class,
+            sel(c"quitLanMouse:"),
+            quit_lan_mouse as *const c_void,
+            c"v@:@".as_ptr(),
+        );
+        objc_registerClassPair(class);
+        class as usize
+    }) as Class
+}
+
+extern "C" fn show_lan_mouse(_this: Id, _cmd: Sel, _sender: Id) {
+    STATUS_ITEM.with(|item| {
+        let item = item.borrow();
+        let Some(item) = item.as_ref() else {
+            return;
+        };
+        if let Some(window) = item.window.upgrade() {
+            window.present();
+        }
+
+        unsafe {
+            let ns_app = msg_send_id(class(c"NSApplication"), sel(c"sharedApplication"));
+            msg_send_void_bool(ns_app, sel(c"activateIgnoringOtherApps:"), 1);
+        }
+    });
+}
+
+extern "C" fn quit_lan_mouse(_this: Id, _cmd: Sel, _sender: Id) {
+    STATUS_ITEM.with(|item| {
+        if let Some(app) = item.borrow().as_ref().and_then(|item| item.app.upgrade()) {
+            app.quit();
+        }
+    });
+}
+
+unsafe fn class(name: &CStr) -> Class {
+    let class = objc_getClass(name.as_ptr());
+    assert!(!class.is_null(), "missing Objective-C class {name:?}");
+    class
+}
+
+unsafe fn sel(name: &CStr) -> Sel {
+    sel_registerName(name.as_ptr())
+}
+
+unsafe fn nsstring(value: &CStr) -> Id {
+    msg_send_id_ptr(
+        class(c"NSString"),
+        sel(c"stringWithUTF8String:"),
+        value.as_ptr(),
+    )
+}
+
+#[link(name = "objc")]
+extern "C" {
+    fn objc_allocateClassPair(superclass: Class, name: *const c_char, extra_bytes: usize) -> Class;
+    fn objc_getClass(name: *const c_char) -> Class;
+    fn objc_registerClassPair(class: Class);
+    fn sel_registerName(name: *const c_char) -> Sel;
+    fn class_addMethod(class: Class, name: Sel, imp: *const c_void, types: *const c_char) -> Bool;
+}
+
+#[link(name = "AppKit", kind = "framework")]
+extern "C" {}
+
+#[link(name = "objc")]
+extern "C" {
+    #[link_name = "objc_msgSend"]
+    fn msg_send_id(receiver: Id, selector: Sel) -> Id;
+    #[link_name = "objc_msgSend"]
+    fn msg_send_id_f64(receiver: Id, selector: Sel, value: c_double) -> Id;
+    #[link_name = "objc_msgSend"]
+    fn msg_send_id_id_sel_id(receiver: Id, selector: Sel, a: Id, b: Sel, c: Id) -> Id;
+    #[link_name = "objc_msgSend"]
+    fn msg_send_id_id_id(receiver: Id, selector: Sel, a: Id, b: Id) -> Id;
+    #[link_name = "objc_msgSend"]
+    fn msg_send_id_id(receiver: Id, selector: Sel, a: Id) -> Id;
+    #[link_name = "objc_msgSend"]
+    fn msg_send_void_size(receiver: Id, selector: Sel, width: c_double, height: c_double);
+    #[link_name = "objc_msgSend"]
+    fn msg_send_id_ptr(receiver: Id, selector: Sel, value: *const c_char) -> Id;
+    #[link_name = "objc_msgSend"]
+    fn msg_send_id_usize(receiver: Id, selector: Sel, value: usize) -> Id;
+    #[link_name = "objc_msgSend"]
+    fn msg_send_usize(receiver: Id, selector: Sel) -> usize;
+    #[link_name = "objc_msgSend"]
+    fn msg_send_void_bool(receiver: Id, selector: Sel, value: Bool);
+    #[link_name = "objc_msgSend"]
+    fn msg_send_void_id(receiver: Id, selector: Sel, value: Id);
+    #[link_name = "objc_msgSend"]
+    fn msg_send_bool_usize(receiver: Id, selector: Sel, value: usize) -> Bool;
+}

scripts/copy-macos-dylib.sh

@@ -43,6 +43,9 @@ bundle_path=$(dirname "$(dirname "$(dirname "$exec_path")")")
 # Path to the Frameworks directory
 fwks_path="$bundle_path/Contents/Frameworks"
 mkdir -p "$fwks_path"
+# Path to bundled GTK/GSettings data
+resources_path="$bundle_path/Contents/Resources"
+share_path="$resources_path/share"
 
 # Copy and fix references for a binary (executable or dylib)
 #
@@ -58,6 +61,10 @@ fix_references() {
   libs=$(otool -L "$bin" | awk -v homebrew="$homebrew_path" '$0 ~ homebrew {print $1}')
 
   echo "$libs" | while IFS= read -r old_path; do
+    if [ -z "$old_path" ]; then
+      continue
+    fi
+
     local base_name="$(basename "$old_path")"
     local dest="$fwks_path/$base_name"
 
@@ -81,6 +88,42 @@ fix_references() {
 
 fix_references "$exec_path"
 
+copy_runtime_data() {
+  mkdir -p "$share_path"
+
+  if [ -d "$homebrew_path/share/glib-2.0/schemas" ]; then
+    mkdir -p "$share_path/glib-2.0"
+    rm -rf "$share_path/glib-2.0/schemas"
+    cp -RL "$homebrew_path/share/glib-2.0/schemas" "$share_path/glib-2.0/schemas"
+    if command -v glib-compile-schemas >/dev/null 2>&1; then
+      glib-compile-schemas "$share_path/glib-2.0/schemas"
+    elif [ -x "$homebrew_path/bin/glib-compile-schemas" ]; then
+      "$homebrew_path/bin/glib-compile-schemas" "$share_path/glib-2.0/schemas"
+    fi
+  fi
+
+  if [ -d "$homebrew_path/share/gtk-4.0" ]; then
+    rm -rf "$share_path/gtk-4.0"
+    cp -RL "$homebrew_path/share/gtk-4.0" "$share_path/gtk-4.0"
+  fi
+
+  if [ -d "$homebrew_path/share/icons/Adwaita" ]; then
+    mkdir -p "$share_path/icons"
+    rm -rf "$share_path/icons/Adwaita"
+    cp -RL "$homebrew_path/share/icons/Adwaita" "$share_path/icons/Adwaita"
+  fi
+}
+
+copy_runtime_data
+
+# cargo-bundle preserves the source path under Contents/Resources (so
+# `target/menubar-template.png` lands at `Resources/target/...`). Flatten it
+# so NSBundle pathForResource: finds the file at the Resources root.
+if [ -f "$resources_path/target/menubar-template.png" ]; then
+  mv "$resources_path/target/menubar-template.png" "$resources_path/menubar-template.png"
+  rmdir "$resources_path/target" 2>/dev/null || true
+fi
+
 # Ensure the main executable has our Frameworks path in its RPATH
 if ! otool -l "$exec_path" | grep -q "@executable_path/../Frameworks"; then
   echo "Adding RPATH to $exec_path"

scripts/makeicns.sh

@@ -67,12 +67,13 @@ magick -size ${CANVAS}x${CANVAS} xc:none \
 # 3) Composite the artwork onto the background, centered inside the content area.
 magick "$workdir/background.png" \
     "$workdir/content.png" -geometry +${CONTENT_OFFSET}+${CONTENT_OFFSET} -composite \
-    "$workdir/icon-1024.png"
+    -colorspace sRGB -type TrueColorAlpha PNG32:"$workdir/icon-1024.png"
 
 # 4) Generate each iconset size from the master so all sizes share the same
 #    squircle proportions and look consistent at every resolution.
 for size in 1024 512 256 128 64 32 16; do
-    magick "$workdir/icon-1024.png" -resize ${size}x${size} "$workdir/${size}.png"
+    magick "$workdir/icon-1024.png" -resize ${size}x${size} \
+        -colorspace sRGB -type TrueColorAlpha PNG32:"$workdir/${size}.png"
 done
 
 cp "$workdir/1024.png" "$iconset"/icon_512x512@2x.png
@@ -86,4 +87,51 @@ cp "$workdir/32.png"   "$iconset"/icon_32x32.png
 cp "$workdir/32.png"   "$iconset"/icon_16x16@2x.png
 cp "$workdir/16.png"   "$iconset"/icon_16x16.png
 
-iconutil -c icns "$iconset" -o "$icns"
+mkdir -p "$(dirname "$icns")"
+
+# Menu bar template icon: flatten all RGB channels to 0 (black) while keeping
+# alpha so the artwork reads as a clean silhouette. NSStatusBarButton tints
+# template images to match the menu bar appearance in light and dark modes.
+menubar_template="$(dirname "$icns")/menubar-template.png"
+rsvg-convert -w 44 -h 44 "$svg" -o "$workdir/menubar-44.png"
+magick "$workdir/menubar-44.png" -channel RGB -evaluate set 0 +channel \
+    "$menubar_template"
+
+if ! iconutil -c icns "$iconset" -o "$icns"; then
+    if ! command -v perl >/dev/null 2>&1; then
+        echo "iconutil failed and perl is not available for the fallback icns writer" >&2
+        exit 1
+    fi
+
+    echo "iconutil rejected the iconset; writing icns directly" >&2
+    perl - "$icns" "$iconset" <<'PERL'
+use strict;
+use warnings;
+
+my ($icns, $iconset) = @ARGV;
+my @icons = (
+    [ 'icp4', "$iconset/icon_16x16.png" ],
+    [ 'ic11', "$iconset/icon_16x16\@2x.png" ],
+    [ 'icp5', "$iconset/icon_32x32.png" ],
+    [ 'ic12', "$iconset/icon_32x32\@2x.png" ],
+    [ 'ic07', "$iconset/icon_128x128.png" ],
+    [ 'ic13', "$iconset/icon_128x128\@2x.png" ],
+    [ 'ic08', "$iconset/icon_256x256.png" ],
+    [ 'ic14', "$iconset/icon_256x256\@2x.png" ],
+    [ 'ic09', "$iconset/icon_512x512.png" ],
+    [ 'ic10', "$iconset/icon_512x512\@2x.png" ],
+);
+
+my $body = '';
+for my $icon (@icons) {
+    my ($type, $path) = @$icon;
+    open my $fh, '<:raw', $path or die "$path: $!";
+    local $/;
+    my $png = <$fh>;
+    $body .= $type . pack('N', length($png) + 8) . $png;
+}
+
+open my $out, '>:raw', $icns or die "$icns: $!";
+print {$out} 'icns' . pack('N', length($body) + 8) . $body;
+PERL
+fi