I was very excited to find Input Method Kit. I was planning on creating software implementations of various specialized hardware keyboards.
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/InputMethodKitFrameworkRef/
Unfortunately I have found that Input Method Kit does not catch NSEvents of type NSKeyUp.
rdar://21376535
This immediately disqualifies all "chorded" input methods. One cannot calculate chording without knowing when keys are pressed down and (importantly) when they go back up.
https://en.wikipedia.org/wiki/Chorded_keyboard
Because Input Method Kit does not catch NSKeyUp events, I cannot calculate if keys are being pressed at the same time. Chording keyboard input methods will thus not work.
Other OS X technologies such as CGEventTap or [NSEvent addLocalMonitorForEventsMatchingMask:] allow for monitoring key events of NSKeyUp, in addition to NSKeyDown or other types. Input Method Kit only allows monitoring of NSKeyDown.
Additionally, returning `NSKeyUpMask` from IMKStateSetting `recognizedEvents:` does NOT enable the NSKeyUp events in IMKit. It seems like it should.
- (NSUInteger)recognizedEvents:(id)sender {
return NSKeyUpMask;
}
Using `recognizedEvents:` works for some other event types, such as FlagsChanged. But it doesn't work for KeyUp.
Steps to Reproduce:
1. Implement an Input Method Kit app (similar to the NumberInput Apple sample code)
2. Implement the IMKit method `handleEvent:client:`
3. Activate your Input Method
4. As you press keys, notice that the `NSKeyDown` events are seen and handled by your input method.
5. As the keys spring back up, notice that `NSKeyUp` events are NOT seen or handled by your input method.
Expected Results:
The input method should see both NSKeyDown and NSKeyUp events.
IMKStateSetting `recognizedEvents:` allows setting of NSKeyUpMask.
NSKeyUp events are *vital* for many input methods, such as chorded keyboards.
Actual Results:
NSKeyUp events are not observed by your input method. Only NSKeyDown events are seen.
Unable to handle NSKeyUp events.
Unable to implement a software chorded keyboard input method
rdar://21376535
