listen for key events globally

[seeplusplus]

I am extremely new to druid, so I apologize if this isn't the right place for this.

The motivation is this issue.

Is global/unfocused key event capturing something that's supported in druid? I looked at the event_viewer example and it looks like it only works if the window (and more specifically the widget the controller is wrapped around) is in focus. it also appears that media key event capturing is spotty in Linux. (on my machine media keys aren't captured at all, on some machines it seems that the events are firing some times, but not always?)

Edit: After a quick glance at the gtk implementation for window, it looks like we're connecting key_press/key_release events at the window level, meaning we would only receive keyboard events while the window is in focus. Assuming that's true, I'm hoping this could be a place to discuss a design that supports for listening for events globally.

[cmyr]

So long-term yes I would like some concept of 'ambient focus' where we will treat key events more like normal events, and just send them down the tree until handled.

Currently, this doesn't exist; you need to do something a bit hacky, like have a custom Controller at the root of the tree that takes focus, and that then sends the events where you want them. Unfortunately it can't send them using the normal Event mechanism, since druid will check to see if a widget has focus before it delivers a key event. 😒

edit: That said I'm going to coopt this as a tracking issue for this feature, which I'm calling "ambient focus"; there's some previous discussion here, for instance but I don't see a concrete issue.

[Ciantic]

Global key (device event) capture should be optional, that shouldn't be enabled by default. It also may be detected as key logger by anti-virus programs.

It can also cause hog unneccessary CPU in Windows. e.g. winit does that, and it eats CPU even though window is not visible or minimized..

[cmyr]

yes you're right I've misread the issue, listening to key events globally is definitely not a case I've been thinking hard about, and certainly wouldn't be on the near-term roadmap. I could imagine some mechanism where druid apps could register platform-wide hotkeys, but I'd prefer to see some other mechanism for that..

[PoignardAzur]

Closing this for now.