Keyboard event(CGEvent)'s flags is not correct

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I'm working on an app which encoding input characters into another language (Vietnamese) and I've facing with some issue of Apple documentation.

My code to listen for keyboard events is:

func cgEventCallback (
    proxy: CGEventTapProxy,
    type: CGEventType,
    event: CGEvent,
    refcon: UnsafeMutableRawPointer?
) -> Unmanaged<CGEvent>? {
    switch type {
    case .keyDown:
        print(event.flags, CGEventFlags.maskCommand)

        if (event.flags == CGEventFlags.maskCommand) {
            print("Flag is Command")
        } else {
            print("Flag is not Command")
        }

    default:
        break
    }

    return Unmanaged.passRetained(event)
}

As they said, CGEvent's flags returns the event flags of a Quartz event. So I expect that when I type in Command + C then it should print out:

CGEventFlags(rawValue: 1048576) CGEventFlags(rawValue: 1048576)
Flag is Command

But the issue is that the printed out text is not the same as expected:

CGEventFlags(rawValue: 1048840) CGEventFlags(rawValue: 1048576)
Flag is not Command

Am I misunderstanding about something or is there any way which could help me know what is the current flag of the event?

swift macos
1 Answers

event.flags is an OptionSet representing all flags for the current event. There can be more than one flag set, and that is what is happening in your case:

event.flags  = 1048840 (decimal) = 100108 (hex)
.maskCommand = 1048576 (decimal) = 100000 (hex)

So the correct test is

if event.flags.contains(.maskCommand) { ... }

instead of testing for equality.

user_11874150
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