Event

Type Alias Event 

Source
pub type Event<'a, T> = Event<'a, UserResizeEvent<T>>;

Aliased Type§

pub enum Event<'a, T> {
    NewEvents(StartCause),
    WindowEvent {
        window_id: WindowId,
        event: WindowEvent<'a>,
    },
    DeviceEvent {
        device_id: DeviceId,
        event: DeviceEvent,
    },
    UserEvent(UserResizeEvent<T>),
    Suspended,
    Resumed,
    MainEventsCleared,
    RedrawRequested(WindowId),
    RedrawEventsCleared,
    LoopDestroyed,
}

Variants§

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NewEvents(StartCause)

Emitted when new events arrive from the OS to be processed.

This event type is useful as a place to put code that should be done before you start processing events, such as updating frame timing information for benchmarking or checking the [StartCause][crate::event::StartCause] to see if a timer set by ControlFlow::WaitUntil has elapsed.

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WindowEvent

Emitted when the OS sends an event to a winit window.

Fields

§window_id: WindowId
§event: WindowEvent<'a>
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DeviceEvent

Emitted when the OS sends an event to a device.

Fields

§device_id: DeviceId
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UserEvent(UserResizeEvent<T>)

Emitted when an event is sent from EventLoopProxy::send_event

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Suspended

Emitted when the application has been suspended.

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Resumed

Emitted when the application has been resumed.

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MainEventsCleared

Emitted when all of the event loop’s input events have been processed and redraw processing is about to begin.

This event is useful as a place to put your code that should be run after all state-changing events have been handled and you want to do stuff (updating state, performing calculations, etc) that happens as the “main body” of your event loop. If your program only draws graphics when something changes, it’s usually better to do it in response to Event::RedrawRequested, which gets emitted immediately after this event. Programs that draw graphics continuously, like most games, can render here unconditionally for simplicity.

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RedrawRequested(WindowId)

Emitted after MainEventsCleared when a window should be redrawn.

This gets triggered in two scenarios:

  • The OS has performed an operation that’s invalidated the window’s contents (such as resizing the window).
  • The application has explicitly requested a redraw via Window::request_redraw.

During each iteration of the event loop, Winit will aggregate duplicate redraw requests into a single event, to help avoid duplicating rendering work.

Mainly of interest to applications with mostly-static graphics that avoid redrawing unless something changes, like most non-game GUIs.

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RedrawEventsCleared

Emitted after all RedrawRequested events have been processed and control flow is about to be taken away from the program. If there are no RedrawRequested events, it is emitted immediately after MainEventsCleared.

This event is useful for doing any cleanup or bookkeeping work after all the rendering tasks have been completed.

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LoopDestroyed

Emitted when the event loop is being shut down.

This is irreversible - if this event is emitted, it is guaranteed to be the last event that gets emitted. You generally want to treat this as an “do on quit” event.