How to detect Exposé activation

[gekko513]

In a Cocoa / Objective C app, how do I detect if Exposé has been activated?

 

[Rincewind42]

In a Cocoa / Objective C app, how do I detect if Exposé has been activated?

It is not currently possible from any kind of application to detect if Exposé has been activated. It has been proposed (and I believe a feature request filed) for an asynchronous notification, but that won't arrive until at least 10.4 (depends on when the request is dealt with).

What are you trying to do?

 

[mnkeybsness]

I'm curious... why would you want to detect if Exposé was activated?

 

[gekko513]

It is not currently possible from any kind of application to detect if Exposé has been activated. It has been proposed (and I believe a feature request filed) for an asynchronous notification, but that won't arrive until at least 10.4 (depends on when the request is dealt with).

What are you trying to do?

There's a bug in the window system that causes the coordinate system for a window to become corrupted if the window is programatically moved while exposé is activated.

I'm currently developing my first OSX app. It's a widget that makes a picture move in and out of the screen, sort of like a peekaboo. When exposé is activated, the window just keeps moving ... which is kinda cool, but unfortunately causes a [self setFrameOrigin:NSMakePoint(0, 0)] to not move the window to the bottom left corner after Exposé is deactivated.

I thought I could fix it by detecting exposé and just not move the window while it was activated. Now I'm not really sure what I can do to work around this.

 

[Rincewind42]

There's a bug in the window system that causes the coordinate system for a window to become corrupted if the window is programatically moved while exposé is activated.

I'm currently developing my first OSX app. It's a widget that makes a picture move in and out of the screen, sort of like a peekaboo. When exposé is activated, the window just keeps moving ... which is kinda cool, but unfortunately causes a [self setFrameOrigin:NSMakePoint(0, 0)] to not move the window to the bottom left corner after Exposé is deactivated.

I thought I could fix it by detecting exposé and just not move the window while it was activated. Now I'm not really sure what I can do to work around this.

I wasn't aware of that bug, but maybe I can offer a few alternative designs.
Maybe you can use an overlay window and just draw your image in the right position within that window rather than moving the window?
If you use a non-exposéd window (like a floating/utility type window) then it should be hidden during Exposé, and maybe that will avoid the issue?

 

[gekko513]

I wasn't aware of that bug, but maybe I can offer a few alternative designs.
Maybe you can use an overlay window and just draw your image in the right position within that window rather than moving the window?
If you use a non-exposéd window (like a floating/utility type window) then it should be hidden during Exposé, and maybe that will avoid the issue?

Moving the content instead of the window is a good idea, I have to sacrifice the possibility of peekabooing from all edges of the screen though (or use a giant window ). The app initially used a always-on-top-window that disappeared on show-windows-exposé, it didn't however disappear on show-desktop-exposé, so that doesn't work, unfortunately.