Feature Request: Window Moved and Resized Events Hi Garry,

bad_wolf

Hi Garry,

While experimenting with saving and restoring window positions, I noticed that the current Resize event fires continuously while a window is being moved or resized — effectively for every small movement.

Would it be possible to add events such as Moved and Resized that fire once after the user has finished moving or resizing the window?

This would be particularly useful for saving window position and size. Saving directly from Resize could result in many unnecessary file writes, while using a timer to detect when movement has stopped feels more like a workaround.

Saving the position in the window's Closing event is another possibility, but there is a disadvantage: if the application crashes or is terminated unexpectedly, the latest window position may never be saved. With Moved and Resized events, the position could be saved as soon as the user finishes changing it, without continuously writing to disk.

Something like:

Resize — continues to fire during movement/resizing as it does now
Moved — fires once when the user finishes moving the window
Resized — fires once when the user finishes resizing the window

Of course, there may already be a better way of accomplishing this that I haven't discovered yet.

Thank you for looking into my request.

Kind regards,
Chris

MikeB

bad_wolf i do all of the saving in the window close event. I understand your concern about losing the chance to save the data if the app crashes. An exception like that for me is deemed an acceptable instance when the data isn’t available.

I do have a concern about whether adding more window events will cause additional overhead in the vm having to process those messages. Only Garry knows the answer to that and hopefully he can weigh in on that question.

bad_wolf

Thank you, MikeB. That is a fair concern. If exposing these events would create meaningful additional VM overhead, I would prefer to continue saving the window state in the Closing event. Garry will know whether the underlying window system already processes these notifications and whether exposing them would carry any measurable cost.

Syntec

Further to this, could we get Maximise, Minimise, and Restore Methods for windows? I am sure there are some others missing as well

Garry

Thanks Chris, Mike and Syntec.

I’ve implemented all of these additions for the next release:
https://feedback.objo.dev/feature/1353
https://feedback.objo.dev/feature/1354

Window now has two completion events:

Moved fires after the window position has remained stable for 250 milliseconds.
Resized fires after the window size has remained stable for 250 milliseconds.

The existing Resize event remains continuous, so it can still be used for live layout work.

Regarding performance, Avalonia already receives the native position and size notifications. Objo coalesces those notifications before entering the VM, using a lazily created, reusable timer only when a corresponding Objo event handler exists. A window without Moved or Resized handlers does not create the timer or queue completion callbacks. I also optimised the continuous Resize path so it no longer queues VM callbacks when the window has no Resize handler.

A pause of at least 250 milliseconds during a longer drag can produce a completion event for that burst. Resizing from the top or left may produce both Moved and Resized, because the window’s position and size have both changed.

Following Syntec’s suggestion, I’ve also added these methods:

Maximise() puts the window into its maximised state.
Minimise() puts the window into its minimised state.
Restore() returns the window to its normal state.

These are one-shot native state changes and introduce no continuing VM overhead. Maximisable and Minimisable control whether the user can perform those actions through the platform’s window controls; they do not prevent application code from calling the new methods.

The existing SetFullScreen() and ExitFullScreen() methods remain available. Restore() can also return a full-screen window to its normal state.

bad_wolf

Hello Garry,

Thank you for adding the Moved and Resized events.

Kind regards,

Chris

Garry

You're very welcome 🙂