fix: don't trigger ui refreshes if the app is not active

alt-tab-macos/logic/Application.swift

@@ -66,11 +66,12 @@ class Application: NSObject {
 
 func axObserverApplicationCallback(observer: AXObserver, element: AXUIElement, notificationName: CFString, applicationPointer: UnsafeMutableRawPointer?) -> Void {
     let application = Unmanaged<Application>.fromOpaque(applicationPointer!).takeUnretainedValue()
+    let app = App.shared as! App
     let type = notificationName as String
     debugPrint("OS event: " + type, element.title())
     switch type {
         case kAXApplicationActivatedNotification:
-            guard !(App.shared as! App).appIsBeingUsed,
+            guard !app.appIsBeingUsed,
                   let appFocusedWindow = element.focusedWindow(),
                   let existingIndex = Windows.listRecentlyUsedFirst.firstIndexThatMatches(appFocusedWindow) else { return }
             Windows.listRecentlyUsedFirst.insert(Windows.listRecentlyUsedFirst.remove(at: existingIndex), at: 0)
@@ -79,7 +80,7 @@ func axObserverApplicationCallback(observer: AXObserver, element: AXUIElement, n
                 guard window.application.axUiElement!.pid() == element.pid() else { continue }
                 window.isHidden = type == kAXApplicationHiddenNotification
             }
-            (App.shared as! App).refreshOpenUi()
+            app.refreshOpenUi()
         case kAXWindowCreatedNotification:
             guard element.isActualWindow() else { return }
             // a window being un-minimized can trigger kAXWindowCreatedNotification
@@ -89,9 +90,9 @@ func axObserverApplicationCallback(observer: AXObserver, element: AXUIElement, n
             Windows.moveFocusedWindowIndexAfterWindowCreatedInBackground()
             // TODO: find a better way to get thumbnail of the new window
             window.refreshThumbnail()
-            (App.shared as! App).refreshOpenUi()
+            app.refreshOpenUi()
         case kAXFocusedWindowChangedNotification:
-            guard !(App.shared as! App).appIsBeingUsed,
+            guard !app.appIsBeingUsed,
                   element.isActualWindow(),
                   let existingIndex = Windows.listRecentlyUsedFirst.firstIndexThatMatches(element) else { return }
             Windows.listRecentlyUsedFirst.insert(Windows.listRecentlyUsedFirst.remove(at: existingIndex), at: 0)

alt-tab-macos/logic/Window.swift

@@ -100,27 +100,28 @@ class Window {
 
 func axObserverWindowCallback(observer: AXObserver, element: AXUIElement, notificationName: CFString, _: UnsafeMutableRawPointer?) -> Void {
     let type = notificationName as String
+    let app = App.shared as! App
     debugPrint("OS event: " + type, element.title())
     switch type {
         case kAXUIElementDestroyedNotification:
             guard let existingIndex = Windows.listRecentlyUsedFirst.firstIndexThatMatches(element) else { return }
             Windows.listRecentlyUsedFirst.remove(at: existingIndex)
-            guard Windows.listRecentlyUsedFirst.count > 0 else { (App.shared as! App).hideUi(); return }
+            guard Windows.listRecentlyUsedFirst.count > 0 else { app.hideUi(); return }
             Windows.moveFocusedWindowIndexAfterWindowDestroyedInBackground(existingIndex)
-            (App.shared as! App).refreshOpenUi()
+            app.refreshOpenUi()
         case kAXWindowMiniaturizedNotification, kAXWindowDeminiaturizedNotification:
             guard let window = Windows.listRecentlyUsedFirst.firstWindowThatMatches(element) else { return }
             window.isMinimized = type == kAXWindowMiniaturizedNotification
             // TODO: find a better way to get thumbnail of the new window (when AltTab is triggered min/demin animation)
             window.refreshThumbnail()
-            (App.shared as! App).refreshOpenUi()
+            app.refreshOpenUi()
         case kAXTitleChangedNotification:
             guard element.isActualWindow(),
                   let window = Windows.listRecentlyUsedFirst.firstWindowThatMatches(element),
                   let newTitle = window.axUiElement.title(),
                   newTitle != window.title else { return }
             window.title = newTitle
-            (App.shared as! App).refreshOpenUi()
+            app.refreshOpenUi()
         default: return
     }
 }

alt-tab-macos/ui/App.swift

@@ -104,6 +104,7 @@ class App: NSApplication, NSApplicationDelegate, NSWindowDelegate {
     }
 
     func refreshOpenUi() {
+        guard appIsBeingUsed else { return }
         let currentScreen = Screen.preferred() // fix screen between steps since it could change (e.g. mouse moved to another screen)
         if uiWorkShouldBeDone { thumbnailsPanel!.refreshCollectionView(currentScreen); debugPrint("refreshCollectionView") }
         if uiWorkShouldBeDone { thumbnailsPanel!.highlightCell(); debugPrint("highlightCellAt") }