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Can't create event loop ondemand #2431
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Not sure how I've missed that issue. You're might not be familiar with such concept, but event loop is a connection to the display server in the first place, dropping it will drop all the windows present, it's more of an exception on macOS, it's not possible at all on X11/Wayland. I think that
It seems like what you want is to run winit's event loop along side some other event loop and not handle everything inside the There's an example how to do
It'll be a solution if you The issue right now is that you're not notified for winit's event loop readiness. So, to sum up, what you want is not possibly theoretically, but it's likely not what you actually need anyway. There's no solution on putting winit's loop inside your Maybe approach with |
The issue title is also misleading. |
run_return
more than once on Mac
I think this is describing what the work-around is doing, not what the original intent seems to be. E.g. see here for added context for this issue: emilk/egui#1889 (based on other issues that @emilk has linked here) I think for the use case behind this issue @emilk would have been happy for all the event handling to be done inside @kchibisov I think you discovered this issue after I linked it to this issue #2706 (comment) and I did that in part because this was an example of a use case that didn't want to move handling of events outside of winit. This issue looks like its about being able to run a temporary (but self-contained) event loop. I think the use case here is being able to have some application (hypothetically could be a command line app, not based on a mainloop) that shows a temporary pop-up UI, e.g. to show stats. I think for this use case the For this use case it's potentially fine that it will completely close any display connections etc when the loop exits because the loop will only exit after the temporary UI has been closed. So I don't think there was any expectation here that |
I think maybe it could be fair to re-open this issue while it looks like the reason for closing it was more based on how the workaround works, not so much about the original issue. The response above looks like it's more applicable to #2706 than here, since the code in #2706 really is explicitly trying to embed Winit event polling into an outer loop. |
I think I've clearly stated why it doesn't applicable? Dropping event loop will drop connection to display server, dropping all the windows along the way. I'm pretty sure you're aware what happens when you close connection to x11/wayland server? I'm not entirely sure wrt X11, but with Wayland everything will die. So it's not possible, we don't even allow creating multiple event loops now anyway. |
yeah, but for this use case I think that's ok. It's sort of like you're responding to the problems with #2706 here. I think here the event loop is only intended to exit after the windows for the temporary UI have been closed, so there won't be any windows to preserve and it's fine that the display connection is dropped. |
Oh, I seems like misread the issue example slightly, indeed looks like a macOS issue. You should be able to open window, do things with it, drop, and open again latter on with different |
@emilk could you try to drop window from inside the event loop and see if it changes anything or if the latest winit has this issue in the first place? I think on macOS and some other platforms you need event loop running for things to work properly. |
Trying the original code on latest
I've tried dropping the fn main() {
use winit::{
event::{Event, WindowEvent},
event_loop::EventLoop,
platform::run_return::EventLoopExtRunReturn,
window::WindowBuilder,
};
fn show_window(event_loop: &mut EventLoop<()>, window_name: &str) {
eprintln!("Creating window {:?}", window_name);
let window = WindowBuilder::new()
.with_title(window_name)
.build(event_loop)
.unwrap();
let our_window_id = window.id();
let mut window = Some(window);
event_loop.run_return(|event, _, control_flow| {
control_flow.set_wait();
match event {
Event::LoopDestroyed => {
eprintln!("Event::LoopDestroyed.");
window = None;
}
// Platform-dependent event handlers to workaround a winit bug
// See: https://github.com/rust-windowing/winit/issues/987
// See: https://github.com/rust-windowing/winit/issues/1619
Event::RedrawEventsCleared if cfg!(windows) => {
println!("rendering");
}
Event::RedrawRequested(_) if !cfg!(windows) => {
println!("rendering");
}
Event::WindowEvent { window_id, .. } if window_id != our_window_id => {
// This can happen if we close a window, and then reopen a new one,
// or if we have multiple windows open.
eprintln!("Ignoring event to old window");
}
Event::WindowEvent {
event: WindowEvent::CloseRequested,
..
} => {
eprintln!("WindowEvent::CloseRequested");
window = None;
control_flow.set_exit();
}
Event::WindowEvent {
event: WindowEvent::Destroyed,
..
} => {
eprintln!("WindowEvent::Destroyed");
window = None;
control_flow.set_exit();
}
_ => (),
}
});
eprintln!("-----------------");
}
let mut event_loop = EventLoop::new();
show_window(&mut event_loop, "First Window");
show_window(&mut event_loop, "Second Window");
} But the result is still the same - I only get one window, and the output is still
Turning on some TRACE logging I get:
|
What if you create event loop each time for a new window, will it work? So you'd create and then drop the loop with the window right away. Though, I have a feeling that you'll be restricted right now to do so, might require patching the check inside winit preventing the multi-loop. |
With --- a/src/event_loop.rs
+++ b/src/event_loop.rs
@@ -112,9 +112,9 @@ impl<T> EventLoopBuilder<T> {
#[inline]
pub fn build(&mut self) -> EventLoop<T> {
static EVENT_LOOP_CREATED: OnceCell<()> = OnceCell::new();
- if EVENT_LOOP_CREATED.set(()).is_err() {
- panic!("Creating EventLoop multiple times is not supported.");
- }
+ // if EVENT_LOOP_CREATED.set(()).is_err() {
+ // panic!("Creating EventLoop multiple times is not supported.");
+ // }
// Certain platforms accept a mutable reference in their API.
#[allow(clippy::unnecessary_mut_passed)]
EventLoop { and recreating the event-loop I get:
|
Just a stab in the dark atm but looking at the macos backend it has a double buffered control flow status (i.e the wait or exit status) for the event loop. ( winit/src/platform_impl/macos/app_state.rs Line 119 in b18295a
I suspicious atm about how that's being updated and read. Setting the status to exit is what will cause the loop to exit after the first window is closed but then when re-running the loop it's notable that the status is only changed once the first event is read and dispatched. As far as winit is concerned I think there's chance that the control flow status might be effectively read as "exit" when re-running the loop, before there is an opportunity to reset it. Just a guess / hunch at the moment but I don't see anything that resets the control flow state in |
there are three callbacks for the second window though before it exits the loop so maybe that's a red herring. |
Overall this re-works the APIs for how an `EventLoop` is run to cover these use-cases, with varying portability caveats: 1. A portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 2. A less portable `run_ondmand()` API that covers the use case in rust-windowing#2431 where applications need to be able to re-run a Winit application multiple times against a persistent `EventLoop`. This doesn't allow `Window` state to carry across separate runs of the loop, but does allow orthogonal re-instantiations of a gui application. Available On: Windows, Linux, MacOS Could be supported on Android if there's a use case Incompatible with iOS, Web Fixes: rust-windowing#2431 3. A less portable (and on MacOS, likely less-optimal) `pump_events()` API that covers the use case in rust-windowing#2706 and allows a Winit event loop to be embedded within an external `loop {}`. Applications call `pump_events()` once per iteration of their own external loop to dispatch all pending Winit events, without blocking the external loop. Available On: Windows, Linux, MacOS, Android Incompatible With: iOS, Web Fixes: rust-windowing#2706 Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) In particular by moving away from `run() -> !` we can stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). `run_return` has been removed, and the overlapping use cases that `run_return` previously partially aimed to support have been split across `run_ondemand` and `pump_events`. Fixes: rust-windowing#2709 Fixes: rust-windowing#2706 Fixes: rust-windowing#2431 TODO: Linux + MacOS support
Overall this re-works the APIs for how an `EventLoop` is run to cover these use-cases, with varying portability caveats: 1. A portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 2. A less portable `run_ondmand()` API that covers the use case in rust-windowing#2431 where applications need to be able to re-run a Winit application multiple times against a persistent `EventLoop`. This doesn't allow `Window` state to carry across separate runs of the loop, but does allow orthogonal re-instantiations of a gui application. Available On: Windows, Linux, MacOS Could be supported on Android if there's a use case Incompatible with iOS, Web Fixes: rust-windowing#2431 3. A less portable (and on MacOS, likely less-optimal) `pump_events()` API that covers the use case in rust-windowing#2706 and allows a Winit event loop to be embedded within an external `loop {}`. Applications call `pump_events()` once per iteration of their own external loop to dispatch all pending Winit events, without blocking the external loop. Available On: Windows, Linux, MacOS, Android Incompatible With: iOS, Web Fixes: rust-windowing#2706 Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) In particular by moving away from `run() -> !` we can stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). `run_return` has been removed, and the overlapping use cases that `run_return` previously partially aimed to support have been split across `run_ondemand` and `pump_events`. Fixes: rust-windowing#2709 Fixes: rust-windowing#2706 Fixes: rust-windowing#2431 TODO: Linux + MacOS support
Overall this re-works the APIs for how an `EventLoop` is run to cover these use-cases, with varying portability caveats: 1. A portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 2. A less portable `run_ondmand()` API that covers the use case in rust-windowing#2431 where applications need to be able to re-run a Winit application multiple times against a persistent `EventLoop`. This doesn't allow `Window` state to carry across separate runs of the loop, but does allow orthogonal re-instantiations of a gui application. Available On: Windows, Linux, MacOS Could be supported on Android if there's a use case Incompatible with iOS, Web Fixes: rust-windowing#2431 3. A less portable (and on MacOS, likely less-optimal) `pump_events()` API that covers the use case in rust-windowing#2706 and allows a Winit event loop to be embedded within an external `loop {}`. Applications call `pump_events()` once per iteration of their own external loop to dispatch all pending Winit events, without blocking the external loop. Available On: Windows, Linux, MacOS, Android Incompatible With: iOS, Web Fixes: rust-windowing#2706 Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) In particular by moving away from `run() -> !` we stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). `run_return` has been removed, and the overlapping use cases that `run_return` previously partially aimed to support have been split across `run_ondemand` and `pump_events`. To help test the changes this adds: examples/window_ondemand examples/window_pump_events examples/window_pump_events_rfd The last _rfd example, tests the interaction between the `rfd` crate and using `pump_events` to embed Winit within an external event loop. Additionally all examples have generally been updated so that `main()` returns a `Result` from `run()` Fixes: rust-windowing#2709 Fixes: rust-windowing#2706 Fixes: rust-windowing#2431 Fixes: rust-windowing#2752 TODO: Linux TODO: split patch up
Overall this re-works the APIs for how an `EventLoop` is run to cover these use-cases, with varying portability caveats: 1. A portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 2. A less portable `run_ondmand()` API that covers the use case in rust-windowing#2431 where applications need to be able to re-run a Winit application multiple times against a persistent `EventLoop`. This doesn't allow `Window` state to carry across separate runs of the loop, but does allow orthogonal re-instantiations of a gui application. Available On: Windows, Linux, MacOS Could be supported on Android if there's a use case Incompatible with iOS, Web Fixes: rust-windowing#2431 3. A less portable (and on MacOS, likely less-optimal) `pump_events()` API that covers the use case in rust-windowing#2706 and allows a Winit event loop to be embedded within an external `loop {}`. Applications call `pump_events()` once per iteration of their own external loop to dispatch all pending Winit events, without blocking the external loop. Available On: Windows, Linux, MacOS, Android Incompatible With: iOS, Web Fixes: rust-windowing#2706 Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) In particular by moving away from `run() -> !` we stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). `run_return` has been removed, and the overlapping use cases that `run_return` previously partially aimed to support have been split across `run_ondemand` and `pump_events`. To help test the changes this adds: examples/window_ondemand examples/window_pump_events examples/window_pump_events_rfd The last _rfd example, tests the interaction between the `rfd` crate and using `pump_events` to embed Winit within an external event loop. Additionally all examples have generally been updated so that `main()` returns a `Result` from `run()` Fixes: rust-windowing#2709 Fixes: rust-windowing#2706 Fixes: rust-windowing#2431 Fixes: rust-windowing#2752 TODO: tidy up macos changes - probably lots of debug stuff left in atm TODO: Linux TODO: ask someone to test orbital changes, made blindly TODO: split patch up
Overall this re-works the APIs for how an `EventLoop` is run to cover these use-cases, with varying portability caveats: 1. A portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 2. A less portable `run_ondmand()` API that covers the use case in rust-windowing#2431 where applications need to be able to re-run a Winit application multiple times against a persistent `EventLoop`. This doesn't allow `Window` state to carry across separate runs of the loop, but does allow orthogonal re-instantiations of a gui application. Available On: Windows, Linux, MacOS Could be supported on Android if there's a use case Incompatible with iOS, Web Fixes: rust-windowing#2431 3. A less portable (and on MacOS, likely less-optimal) `pump_events()` API that covers the use case in rust-windowing#2706 and allows a Winit event loop to be embedded within an external `loop {}`. Applications call `pump_events()` once per iteration of their own external loop to dispatch all pending Winit events, without blocking the external loop. Available On: Windows, Linux, MacOS, Android Incompatible With: iOS, Web Fixes: rust-windowing#2706 Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) In particular by moving away from `run() -> !` we stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). `run_return` has been removed, and the overlapping use cases that `run_return` previously partially aimed to support have been split across `run_ondemand` and `pump_events`. To help test the changes this adds: examples/window_ondemand examples/window_pump_events examples/window_pump_events_rfd The last _rfd example, tests the interaction between the `rfd` crate and using `pump_events` to embed Winit within an external event loop. Additionally all examples have generally been updated so that `main()` returns a `Result` from `run()` Fixes: rust-windowing#2709 Fixes: rust-windowing#2706 Fixes: rust-windowing#2431 Fixes: rust-windowing#2752 TODO: X11/Wayland backends TODO: ask someone to test orbital changes, made blindly TODO: split patch up Second pass over the windows backend I had totally underestimated what was involved in updating the windows backend since I hadn't seen the special `wait_thread` that was also dispatching messages and implementing control_flow timeouts via MsgWaitForMultipleObjects, nor had I grokked all the special stuff being done with `WM_PAINT` messages. This "breaks" the MainEventsCleared -> RedrawRequested -> RedrawEventsCleared ordering guarantees, similar to how this is anyway inherently broken in the MacOS backend. The switches to using SetTimer to handle control_flow Wait timeouts and removes the need to use MsgWaitForMultipleObjects. Overall this is a pretty nice simplification of several things TODO: tidy up (lots of debug and misc changes + comments atm) stash
Overall this re-works the APIs for how an `EventLoop` is run to cover these use-cases, with varying portability caveats: 1. A portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 2. A less portable `run_ondmand()` API that covers the use case in rust-windowing#2431 where applications need to be able to re-run a Winit application multiple times against a persistent `EventLoop`. This doesn't allow `Window` state to carry across separate runs of the loop, but does allow orthogonal re-instantiations of a gui application. Available On: Windows, Linux, MacOS Could be supported on Android if there's a use case Incompatible with iOS, Web Fixes: rust-windowing#2431 3. A less portable (and on MacOS, likely less-optimal) `pump_events()` API that covers the use case in rust-windowing#2706 and allows a Winit event loop to be embedded within an external `loop {}`. Applications call `pump_events()` once per iteration of their own external loop to dispatch all pending Winit events, without blocking the external loop. Available On: Windows, Linux, MacOS, Android Incompatible With: iOS, Web Fixes: rust-windowing#2706 Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) In particular by moving away from `run() -> !` we stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). `run_return` has been removed, and the overlapping use cases that `run_return` previously partially aimed to support have been split across `run_ondemand` and `pump_events`. To help test the changes this adds: examples/window_ondemand examples/window_pump_events examples/window_pump_events_rfd The last _rfd example, tests the interaction between the `rfd` crate and using `pump_events` to embed Winit within an external event loop. Additionally all examples have generally been updated so that `main()` returns a `Result` from `run()` Fixes: rust-windowing#2709 Fixes: rust-windowing#2706 Fixes: rust-windowing#2431 Fixes: rust-windowing#2752 TODO: X11/Wayland backends TODO: ask someone to test orbital changes, made blindly TODO: split patch up Second pass over the windows backend I had totally underestimated what was involved in updating the windows backend since I hadn't seen the special `wait_thread` that was also dispatching messages and implementing control_flow timeouts via MsgWaitForMultipleObjects, nor had I grokked all the special stuff being done with `WM_PAINT` messages. This "breaks" the MainEventsCleared -> RedrawRequested -> RedrawEventsCleared ordering guarantees, similar to how this is anyway inherently broken in the MacOS backend. The switches to using SetTimer to handle control_flow Wait timeouts and removes the need to use MsgWaitForMultipleObjects. Overall this is a pretty nice simplification of several things TODO: tidy up (lots of debug and misc changes + comments atm) stash
Overall this re-works the APIs for how an `EventLoop` is run to cover these use-cases, with varying portability caveats: 1. A portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 2. A less portable `run_ondmand()` API that covers the use case in rust-windowing#2431 where applications need to be able to re-run a Winit application multiple times against a persistent `EventLoop`. This doesn't allow `Window` state to carry across separate runs of the loop, but does allow orthogonal re-instantiations of a gui application. Available On: Windows, Linux, MacOS Could be supported on Android if there's a use case Incompatible with iOS, Web Fixes: rust-windowing#2431 3. A less portable (and on MacOS, likely less-optimal) `pump_events()` API that covers the use case in rust-windowing#2706 and allows a Winit event loop to be embedded within an external `loop {}`. Applications call `pump_events()` once per iteration of their own external loop to dispatch all pending Winit events, without blocking the external loop. Available On: Windows, Linux, MacOS, Android Incompatible With: iOS, Web Fixes: rust-windowing#2706 Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) In particular by moving away from `run() -> !` we stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). `run_return` has been removed, and the overlapping use cases that `run_return` previously partially aimed to support have been split across `run_ondemand` and `pump_events`. To help test the changes this adds: examples/window_ondemand examples/window_pump_events examples/window_pump_events_rfd The last _rfd example, tests the interaction between the `rfd` crate and using `pump_events` to embed Winit within an external event loop. Additionally all examples have generally been updated so that `main()` returns a `Result` from `run()` Fixes: rust-windowing#2709 Fixes: rust-windowing#2706 Fixes: rust-windowing#2431 Fixes: rust-windowing#2752 TODO: X11/Wayland backends TODO: ask someone to test orbital changes, made blindly TODO: split patch up Second pass over the windows backend I had totally underestimated what was involved in updating the windows backend since I hadn't seen the special `wait_thread` that was also dispatching messages and implementing control_flow timeouts via MsgWaitForMultipleObjects, nor had I grokked all the special stuff being done with `WM_PAINT` messages. This "breaks" the MainEventsCleared -> RedrawRequested -> RedrawEventsCleared ordering guarantees, similar to how this is anyway inherently broken in the MacOS backend. The switches to using SetTimer to handle control_flow Wait timeouts and removes the need to use MsgWaitForMultipleObjects. Overall this is a pretty nice simplification of several things TODO: tidy up (lots of debug and misc changes + comments atm) stash
Overall this re-works the APIs for how an `EventLoop` is run to cover these use-cases, with varying portability caveats: 1. A portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 2. A less portable `run_ondmand()` API that covers the use case in rust-windowing#2431 where applications need to be able to re-run a Winit application multiple times against a persistent `EventLoop`. This doesn't allow `Window` state to carry across separate runs of the loop, but does allow orthogonal re-instantiations of a gui application. Available On: Windows, Linux, MacOS Could be supported on Android if there's a use case Incompatible with iOS, Web Fixes: rust-windowing#2431 3. A less portable (and on MacOS, likely less-optimal) `pump_events()` API that covers the use case in rust-windowing#2706 and allows a Winit event loop to be embedded within an external `loop {}`. Applications call `pump_events()` once per iteration of their own external loop to dispatch all pending Winit events, without blocking the external loop. Available On: Windows, Linux, MacOS, Android Incompatible With: iOS, Web Fixes: rust-windowing#2706 Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) In particular by moving away from `run() -> !` we stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). `run_return` has been removed, and the overlapping use cases that `run_return` previously partially aimed to support have been split across `run_ondemand` and `pump_events`. To help test the changes this adds: examples/window_ondemand examples/window_pump_events examples/window_pump_events_rfd The last _rfd example, tests the interaction between the `rfd` crate and using `pump_events` to embed Winit within an external event loop. Additionally all examples have generally been updated so that `main()` returns a `Result` from `run()` Fixes: rust-windowing#2709 Fixes: rust-windowing#2706 Fixes: rust-windowing#2431 Fixes: rust-windowing#2752 TODO: X11/Wayland backends TODO: ask someone to test orbital changes, made blindly TODO: split patch up
Overall this re-works the APIs for how an `EventLoop` is run to cover these use-cases, with varying portability caveats: 1. A portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 2. A less portable `run_ondmand()` API that covers the use case in rust-windowing#2431 where applications need to be able to re-run a Winit application multiple times against a persistent `EventLoop`. This doesn't allow `Window` state to carry across separate runs of the loop, but does allow orthogonal re-instantiations of a gui application. Available On: Windows, Linux, MacOS Could be supported on Android if there's a use case Incompatible with iOS, Web Fixes: rust-windowing#2431 3. A less portable (and on MacOS, likely less-optimal) `pump_events()` API that covers the use case in rust-windowing#2706 and allows a Winit event loop to be embedded within an external `loop {}`. Applications call `pump_events()` once per iteration of their own external loop to dispatch all pending Winit events, without blocking the external loop. Available On: Windows, Linux, MacOS, Android Incompatible With: iOS, Web Fixes: rust-windowing#2706 Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) In particular by moving away from `run() -> !` we stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). `run_return` has been removed, and the overlapping use cases that `run_return` previously partially aimed to support have been split across `run_ondemand` and `pump_events`. To help test the changes this adds: examples/window_ondemand examples/window_pump_events examples/window_pump_events_rfd The last _rfd example, tests the interaction between the `rfd` crate and using `pump_events` to embed Winit within an external event loop. Additionally all examples have generally been updated so that `main()` returns a `Result` from `run()` Fixes: rust-windowing#2709 Fixes: rust-windowing#2706 Fixes: rust-windowing#2431 Fixes: rust-windowing#2752 TODO: X11/Wayland backends TODO: ask someone to test orbital changes, made blindly TODO: split patch up
Overall this re-works the APIs for how an `EventLoop` is run to cover these use-cases, with varying portability caveats: 1. A portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 2. A less portable `run_ondmand()` API that covers the use case in rust-windowing#2431 where applications need to be able to re-run a Winit application multiple times against a persistent `EventLoop`. This doesn't allow `Window` state to carry across separate runs of the loop, but does allow orthogonal re-instantiations of a gui application. Available On: Windows, Linux, MacOS Could be supported on Android if there's a use case Incompatible with iOS, Web Fixes: rust-windowing#2431 3. A less portable (and on MacOS, likely less-optimal) `pump_events()` API that covers the use case in rust-windowing#2706 and allows a Winit event loop to be embedded within an external `loop {}`. Applications call `pump_events()` once per iteration of their own external loop to dispatch all pending Winit events, without blocking the external loop. Available On: Windows, Linux, MacOS, Android Incompatible With: iOS, Web Fixes: rust-windowing#2706 Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) In particular by moving away from `run() -> !` we stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). `run_return` has been removed, and the overlapping use cases that `run_return` previously partially aimed to support have been split across `run_ondemand` and `pump_events`. To help test the changes this adds: examples/window_ondemand examples/window_pump_events examples/window_pump_events_rfd The last _rfd example, tests the interaction between the `rfd` crate and using `pump_events` to embed Winit within an external event loop. Additionally all examples have generally been updated so that `main()` returns a `Result` from `run()` Fixes: rust-windowing#2709 Fixes: rust-windowing#2706 Fixes: rust-windowing#2431 Fixes: rust-windowing#2752 TODO: X11/Wayland backends TODO: ask someone to test orbital changes, made blindly TODO: split patch up
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicitly, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicitly, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicitly, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing #2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing #2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing rust-windowing#2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing rust-windowing#2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
This adds two new extensions for running a Winit event loop which will replace `EventLoopExtRunReturn` The `run_return` API is trying to solve multiple problems and address multiple, unrelated, use cases but in doing so it is not succeeding at addressing any of them fully. The notable use cases we have are: 1. Applications want to be able to implement their own external event loop and call some Winit API to poll / pump events, once per iteration of their own loop, without blocking the outer, external loop. Addressing #2706 2. Applications want to be able to re-run separate instantiations of some Winit-based GUI and want to allow the event loop to exit with a status, and then later be able to run the loop again for a new instantiation of their GUI. Addressing #2431 It's very notable that these use cases can't be supported across all platforms and so they are extensions, similar to `EventLoopExtRunReturn` The intention is to support these extensions on: - Windows - Linux (X11 + Wayland) - macOS - Android These extensions aren't compatible with Web or iOS though. Each method of running the loop will behave consistently in terms of how `NewEvents(Init)`, `Resumed` and `LoopDestroyed` events are dispatched (so portable application code wouldn't necessarily need to have any awareness of which method of running the loop was being used) Once all backends have support for these extensions then we can remove `EventLoopExtRunReturn` For simplicity, the extensions are documented with the assumption that the above platforms will be supported. This patch makes no functional change, it only introduces these new extensions so we can then handle adding platform-specific backends in separate pull requests, so the work can be landed in stages.
I want to be able to open a window, use
event_loop.run_return
to process some events on it, then close it, and then later open another window. When I try this on my Mac, I find that the second time I runrun_return
I getEvent::LoopDestroyed
almost immediately, and the new window is destroyed. This is the code I'm running:And this is the output:
The
WindowEvent::CloseRequested
is me closing the window, but the second window also closes without any reason.According to @zu1k, this is also a problem on Windows, but there it can be fixed by adding the following code after the first
run_return
:Related issue: emilk/egui#1919
One very bad work-around is to calli
run_return
multiple times, like so:This still spams
Event::LoopDestroyed
over and over again, but the window stays up. However, it uses up ALL the CPU of one core, so this is NOT a viable solution.The text was updated successfully, but these errors were encountered: