Function run_app 

pub fn run_app<P, A>(
    config: WindowConfig,
    presenter: P,
    app: A,
) -> Result<(), EventLoopError>
where
    P: Presenter + 'static,
    A: App<WindowBackend<P>> + 'static,

Drive an App from the windowed event loop.

This is the inverted driver: winit owns the event loop and calls back into the app on each redraw, rather than the app owning a while loop.

Each frame builds a Frame with a wall-clock dt measured via web_time::Instant: a plain std::time::Instant re-export on native, backed by the browser’s Performance.now() on wasm32 (where std::time::Instant itself is unavailable). Calls App::update.

On Flow::Exit the event loop exits gracefully (via [ActiveEventLoop::exit]) instead of force-exiting the process, so the stack unwinds normally and Drop impls up the call chain (unflushed writes, GPU/surface teardown, app-level RAII) run before the process exits. This works the same on wasm: winit’s web backend implements ActiveEventLoop::exit by stopping its requestAnimationFrame-driven runner rather than leaving it a no-op.

See run_windowed’s “Presenting is automatic” section: the app’s update implementation no longer needs to call Terminal::present itself here either, this driver presents automatically after each call, except on Flow::Idle, where the present is skipped entirely and the previous frame stays on screen.

Resizing is not automatic

This driver does not resize the Terminal itself. On every window resize it pushes Event::Resize with the new cell dimensions; the app must poll that event and call Terminal::resize to resize the terminal’s own grid buffers.

Errors

Returns [winit::error::EventLoopError] if the event loop cannot be created or fails while running.