How can I check whether Exposé is being activated or not?

Question

Hi,

I'm creating an application that emulates MacBook's multi-touch Trackpad. As you may know, on MacBook's trackpad

• if you swipe 4 fingers up, it triggers the Show Desktop.
• if you swipe 4 fingers down, it shows the Exposé.

However, if the Show Desktop is being activated and you swipe 4 fingers down, it will come back to the normal mode. The same goes with the Exposé: if the Exposé is being activated and you swipe 4 fingers up, it will also come back to the normal mode.

Here is the problem: I use the keyboard shortcut F3 to show the Exposé and F11 to show the Show Desktop. The problem is, when the Show Desktop is being activated, if I press F3, it will go straight to the Exposé. And when the Exposé is being activated, if I press F11 it will go straight to the Show Desktop. But I want it to behave like Trackpad, which I guess its code may look like this

- FourFingersDidSwipeUp {
    if (isExposeBeingActivated() || isShowDesktopBeingActivated()) {
        pressKey("Esc");
    } else {
        pressKey("F11");
    }
}

But I don't know how to implement the "isExposeBeingActivated()" and "isShowDesktopBeingActivated()" methods. I've tried creating a window and check whether its size has changed (on assumption that if the Expose is being activated, its size should be smaller), but the system always returns the same size. I tried monitoring the background processes during the Expose, but nothing happened. Does anyknow have any suggestions on this?

(I'm sorry if my English sounds weird.)

Answer 1

As far as I know, there's no public interface to any Exposé related functionality beyond the ability to specify the "collection behavior" of your own application's windows.

Answer 2

Hi, came here after reading your email. I understand the problem. After a bit of googling I found out what you already know, that there's really no official API or documentation for Exposé. A very ugly solution I've thought of could be having Exposé trigger a timer equal to the total time it takes to show all windows fully (guessing this is constant). If a swipe up would be done within that timer, it would mean that Exposé would still be active (isExposeBeingActivated()), so you would trigger a cancel instead of a Show Desktop. This wouldn't cover the use of the "slow motion" Exposé (via SHIFT key). Maybe you can detect if it's a normal or "slow motion" Exposé call?

Really sorry if this doesn't make sense at all within your application's scope, guess I'm just really saying the first solution I thought of.

Cheers.

Pedro.