4 — Toasts

A toast is a small, auto-stacking notification anchored to one corner of the window. snora owns the rendering, the stacking, and the lifetime sweep; the application only stores Vec<Toast<Message>> and writes two one-liners.

Three pieces

#![allow(unused)]
fn main() {
use std::time::Instant;
use iced::{Subscription, Task};
use snora::{Toast, ToastIntent, ToastLifetime};

struct App {
    toasts: Vec<Toast<Message>>,
    next_id: u64,
}

#[derive(Debug, Clone)]
enum Message {
    ShowSaved,
    Dismiss(u64),
    ToastTick,                        // framework asks us to sweep
}
}

1. Push a toast

#![allow(unused)]
fn main() {
fn update(&mut self, msg: Message) -> Task<Message> {
    if let Message::ShowSaved = msg {
        let id = self.next_id;
        self.next_id += 1;
        self.toasts.push(Toast::new(
            id,
            ToastIntent::Success,
            "Saved",
            "Document written to disk.",
            Message::Dismiss(id),
        ));
    }
    if let Message::Dismiss(id) = msg {
        self.toasts.retain(|t| t.id != id);
    }
    if let Message::ToastTick = msg {
        snora::toast::sweep_expired(&mut self.toasts, Instant::now());
    }
    Task::none()
}
}

2. Subscribe to TTL ticks

#![allow(unused)]
fn main() {
fn subscription(&self) -> Subscription<Message> {
    snora::toast::subscription(&self.toasts, || Message::ToastTick)
}
}

subscription returns Subscription::none() when the queue holds only persistent toasts (or nothing at all), so the runtime does not wake on an idle screen.

3. Pass the queue to the layout

#![allow(unused)]
fn main() {
fn view(&self) -> iced::Element<'_, Message> {
    let body: iced::Element<'_, Message> = /* … */;
    let layout = snora::AppLayout::new(body)
        .toasts(self.toasts.clone());
    snora::render(layout)
}
}

Lifetime policies

Persistent is for messages the user must acknowledge — completed exports, fatal errors. Transient is for everything else.

Intent → color

ToastIntent is one of Debug, Info, Success, Warning, Error. The engine resolves intents to theme-aware colors automatically.

Position

Toasts anchor at ToastPosition::TopEnd by default (top-right under LTR, top-left under RTL). Override with AppLayout::toast_position(ToastPosition::BottomCenter) etc. The position can be changed at runtime — re-rendering with a different position re-anchors the entire stack on the next frame.

Why not store TTL outside the toast?

Toast carries created_at and lifetime so that any single toast is self-describing: Toast::is_expired(now) is a pure function on the struct, easy to test without setting up renderer state. See the testing guide.

Next

You now know how to build a working snora app. The next page helps you decide whether snora is the right fit for what you are building.