Add a set_focus(bool) interface for getting and losing keyboard focus #152

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1. Engid commented on Oct 21, 2023

   

   Engid

   on Oct 21, 2023

   Last edited by Engid

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   Per ilmai:

   For reference here's what I'm doing on Mac with my own windowing abstraction experiment that I'm using for slint. It's not really production-ready but seems to work as expected based on some testing. https://github.com/ilmai/plugin-things/blob/main/plugin-canvas/src/platform/mac/view.rs#L255

   The boolean is checked here https://github.com/ilmai/plugin-things/blob/main/plugin-canvas/src/platform/mac/view.rs#L66
   Windows and Linux have similar logic

   And set_input_focus() is called from here https://github.com/ilmai/plugin-things/blob/main/nih_plug_slint/src/window_adapter.rs#L318

   ---

   UPDATES 11/12/2023:

   NOTES: set_input_focus() defined here in a permalink url

   ALSO NOTE: further comment from ilmai:

   That's not enough on Windows as you need a separate message window that capture the input since Live and some other hosts don't let keyboard events through to the plugin. And on top of that, you need a message hook to catch modifier key presses since you want to always capture those and not just when the window has input focus.
2. dathinaios commented on Feb 26, 2024

   

   dathinaios

   on Feb 26, 2024

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   (Dionysis from the Rust Audio discord here 🙂👋)

   So, I am giving this a go again. I am reading the baseview code and follow it ok but we need more clarity on what needs to be implemented. Focusing on Mac for now but if we get the interface down it should not be too difficult to implement for other platforms (famous last words 😁).

   I had a look at @ilmai 's code from the link above and I can not see where the input_focus boolean interacts with NSWindow. From a discord conversation @ilmai has said:

   you don't really need to set input focus yourself like that, but the GUI crate (vizia in this case) asking for input focus should dictate if keyboard events are passed to the parent window or not

   That sounds to me as if baseview is not handling the focus but simply storing the boolean and then it is a matter of calling the focus method from Vizia (or other GUI) which I assume already has access to the NSWindow.

   Is this correct? 🤔
3. prokopyl

   added this to the v0.X - Future features & major changes milestone on May 1, 2026
4. prokopyl commented on Oct 2, 2026

   

   prokopyl

   on Oct 2, 2026

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   Closing as this has been implemented in #202, at least the grabbing focus part.

   Releasing focus may be a bit more complex, and I'm not sure releasing focus from the plugin window entirerly is a much needed feature. If it is for you, please tell me here and I'll open a new dedicated issue for focus release.
5. prokopyl

   closed this as completedon Oct 2, 2026