Catch mouse events with CGEvent.tapCreate in Swift on MacOS

Question

I am novice Swift coder trying to catch mouse events as well as keyboard events. It seems I am only doing the latter. The main goal is to allow for «tap-to-click» with Magic Mouse 2 and avoid its loud clicking sound.

Fully working sample at https://github.com/creasty/Keyboard/blob/master/keyboard/AppDelegate.swift

let eventMask = 
    (1 << CGEventType.keyDown.rawValue) | 
    (1 << CGEventType.keyUp.rawValue) | 
    (1 << CGEventType.leftMouseDown.rawValue) | 
    (1 << CGEventType.leftMouseUp.rawValue)

guard let eventTap = CGEvent.tapCreate(
    tap: .cghidEventTap,
    place: .headInsertEventTap,
    options: .defaultTap,
    eventsOfInterest: CGEventMask(eventMask),
    callback: appComponent.eventTapCallback,
    userInfo: nil
) else {
    fatalError("Failed to create event tap")
}

Keyboard presses are caught alright, but no reaction to mouse clicks. Please advise. Thanks.

Xcode Version 12.5.1 (12E507) on MacOS 11.5.2

Where are you writing code? Start with the class name if you are going to post code. — El Tomato, Aug 22 '21 at 22:47
The github code does not tap mouse events. Post a [mre] in the question please, including `eventTapCallback`. Why do you want to catch mouse-down events if you don't want to click? — Willeke, Aug 23 '21 at 09:55
I want mouse "tap" gestures to be caught and converted to mouse "clicks". The term "tap" has two meanings here: EventTap (the technology) and the tap finger movement (slight touch on mouse without full depress). — Andreas F, Aug 23 '21 at 10:53
Thanks @Willeke, I´ve tried `let eventMask = NSEvent.EventTypeMask.any.rawValue` but it does still not react to mouse events. — Andreas F, Aug 23 '21 at 15:49
Which mouse events? I tried your code, added `leftMouseDown`, and it works for me. — Willeke, Aug 24 '21 at 07:50
I must be missing something. I too added `CGEventType.leftMouseDown.rawValue`to the eventMask and a breakpoint at `func handle`which only triggers on key press, not mouse click. — Andreas F, Aug 25 '21 at 16:32
`func handle`? Have you tried a break on `appComponent.eventTapCallback`? — Willeke, Aug 26 '21 at 12:57

score 0 · Answer 1 · answered Aug 27 '21 at 08:16

Thanks to helpful feedback from @Willeke and others, we arrived at the following solution:

diff --git a/keyboard/AppComponent.swift b/keyboard/AppComponent.swift
index 961a81b..abb2f63 100644
--- a/keyboard/AppComponent.swift
+++ b/keyboard/AppComponent.swift
@@ -20,6 +20,8 @@ final class AppComponent {
             if let manager = _eventManager {
                 return manager.handle(proxy: proxy, cgEvent: event)
             }
+        case .leftMouseDown:
+            print("leftMouseDown")
         default:
             break
         }
diff --git a/keyboard/AppDelegate.swift b/keyboard/AppDelegate.swift
index bc39af6..dc16658 100644
--- a/keyboard/AppDelegate.swift
+++ b/keyboard/AppDelegate.swift
@@ -70,8 +70,8 @@ private extension AppDelegate {
     }
 
     func setupEventTap() {
-        let eventMask = (1 << CGEventType.keyDown.rawValue) | (1 << CGEventType.keyUp.rawValue)
-
+        let eventMask = (1 << CGEventType.keyDown.rawValue) | (1 << CGEventType.keyUp.rawValue) | (1 << CGEventType.leftMouseDown.rawValue)
+        
         guard let eventTap = CGEvent.tapCreate(
             tap: .cghidEventTap,
             place: .headInsertEventTap,

Catch mouse events with CGEvent.tapCreate in Swift on MacOS

1 Answers1