Keep macOS control overlays above other apps

src-tauri/src/lib.rs

@@ -4,6 +4,8 @@ mod grid3;
 mod input;
 #[cfg(target_os = "macos")]
 mod macos;
+#[cfg(target_os = "macos")]
+mod macos_overlay_window;
 mod modifier_overlay;
 mod mouse_repeat;
 mod overlay;

src-tauri/src/macos_overlay_window.rs

@@ -0,0 +1,39 @@
+use objc2_app_kit::{
+    NSScreenSaverWindowLevel, NSWindow, NSWindowCollectionBehavior, NSWindowLevel,
+};
+
+const OVERLAY_COLLECTION_BEHAVIOR: NSWindowCollectionBehavior = NSWindowCollectionBehavior(
+    NSWindowCollectionBehavior::CanJoinAllSpaces.0
+        | NSWindowCollectionBehavior::Stationary.0
+        | NSWindowCollectionBehavior::IgnoresCycle.0
+        | NSWindowCollectionBehavior::FullScreenAuxiliary.0,
+);
+
+pub(crate) fn configure(window: &NSWindow) {
+    window.setLevel(overlay_window_level());
+    window.setHidesOnDeactivate(false);
+    window.setCollectionBehavior(OVERLAY_COLLECTION_BEHAVIOR);
+}
+
+fn overlay_window_level() -> NSWindowLevel {
+    NSScreenSaverWindowLevel
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn overlays_use_the_screen_saver_window_level() {
+        assert_eq!(overlay_window_level(), NSScreenSaverWindowLevel);
+    }
+
+    #[test]
+    fn overlay_collection_behavior_is_complete_and_exact() {
+        let expected = NSWindowCollectionBehavior::CanJoinAllSpaces
+            | NSWindowCollectionBehavior::Stationary
+            | NSWindowCollectionBehavior::IgnoresCycle
+            | NSWindowCollectionBehavior::FullScreenAuxiliary;
+        assert_eq!(OVERLAY_COLLECTION_BEHAVIOR, expected);
+    }
+}

src-tauri/src/modifier_overlay.rs

@@ -6,6 +6,8 @@ use tauri::{
 };
 
 use crate::input::ModifierKey;
+#[cfg(target_os = "macos")]
+use crate::macos_overlay_window;
 use crate::state::{emit_state, set_activity, ActivityKind, SharedModel};
 
 const OVERLAY_WINDOW_LABEL: &str = "modifier-overlay";
@@ -65,6 +67,7 @@ impl ModifierOverlay {
         .visible(false)
         .build()
         .map_err(|error| error.to_string())?;
+        configure_platform_window(&window)?;
         window
             .set_ignore_cursor_events(true)
             .map_err(|error| error.to_string())?;
@@ -184,6 +187,21 @@ impl ModifierOverlay {
     }
 }
 
+#[cfg(target_os = "macos")]
+fn configure_platform_window(window: &WebviewWindow) -> Result<(), String> {
+    window
+        .with_webview(|webview| unsafe {
+            let window: &objc2_app_kit::NSWindow = &*webview.ns_window().cast();
+            macos_overlay_window::configure(window);
+        })
+        .map_err(|error| error.to_string())
+}
+
+#[cfg(not(target_os = "macos"))]
+fn configure_platform_window(_window: &WebviewWindow) -> Result<(), String> {
+    Ok(())
+}
+
 impl ModifierKeyOverlayNotifier for ModifierOverlay {
     fn set_active_modifiers(&self, active_modifiers: &[ModifierKey]) {
         self.update(active_modifiers);

src-tauri/src/overlay_macos.rs

@@ -7,12 +7,12 @@ use objc2::rc::Retained;
 use objc2::{AnyThread, MainThreadMarker, MainThreadOnly};
 use objc2_app_kit::{
     NSBackingStoreType, NSBitmapFormat, NSBitmapImageRep, NSCalibratedRGBColorSpace, NSColor,
-    NSEvent, NSImage, NSImageRep, NSImageView, NSPanel, NSScreen, NSStatusWindowLevel,
-    NSWindowCollectionBehavior, NSWindowStyleMask,
+    NSEvent, NSImage, NSImageRep, NSImageView, NSPanel, NSScreen, NSWindowStyleMask,
 };
 use objc2_foundation::{NSArray, NSPoint, NSRect, NSSize};
 use tauri::AppHandle;
 
+use crate::macos_overlay_window;
 use crate::overlay::{render_marker, run_loop, Command, Frame};
 use crate::state::{emit_state, set_activity, ActivityKind, SharedModel};
 
@@ -195,12 +195,7 @@ fn make_panel(mtm: MainThreadMarker) -> Retained<NSPanel> {
     panel.setBackgroundColor(Some(&NSColor::clearColor()));
     panel.setHasShadow(false);
     panel.setIgnoresMouseEvents(true);
-    panel.setLevel(NSStatusWindowLevel);
-    panel.setCollectionBehavior(
-        NSWindowCollectionBehavior::CanJoinAllSpaces
-            | NSWindowCollectionBehavior::FullScreenAuxiliary
-            | NSWindowCollectionBehavior::IgnoresCycle,
-    );
+    macos_overlay_window::configure(&panel);
     panel
 }