Add `timer` example

1 files changed, 180 insertions, 0 deletions

diff --git a/examples/timer.rs b/examples/timer.rs
new file mode 100644
index 00000000..b64b3ef5
--- /dev/null
+++ b/examples/timer.rs
@@ -0,0 +1,180 @@
+use iced::{
+    button, Align, Application, Background, Button, Color, Column, Command,
+    Container, Element, HorizontalAlignment, Length, Row, Settings,
+    Subscription, Text,
+};
+use std::time::{Duration, Instant};
+
+pub fn main() {
+    Timer::run(Settings::default())
+}
+
+struct Timer {
+    duration: Duration,
+    state: State,
+    toggle: button::State,
+    reset: button::State,
+}
+
+enum State {
+    Idle,
+    Ticking { last_tick: Instant },
+}
+
+#[derive(Debug, Clone)]
+enum Message {
+    Toggle,
+    Reset,
+    Tick(Instant),
+}
+
+impl Application for Timer {
+    type Message = Message;
+
+    fn new() -> (Timer, Command<Message>) {
+        (
+            Timer {
+                duration: Duration::default(),
+                state: State::Idle,
+                toggle: button::State::new(),
+                reset: button::State::new(),
+            },
+            Command::none(),
+        )
+    }
+
+    fn title(&self) -> String {
+        String::from("Timer - Iced")
+    }
+
+    fn update(&mut self, message: Message) -> Command<Message> {
+        match message {
+            Message::Toggle => match self.state {
+                State::Idle => {
+                    self.state = State::Ticking {
+                        last_tick: Instant::now(),
+                    };
+                }
+                State::Ticking { .. } => {
+                    self.state = State::Idle;
+                }
+            },
+            Message::Tick(now) => match &mut self.state {
+                State::Ticking { last_tick } => {
+                    self.duration += now - *last_tick;
+                    *last_tick = now;
+                }
+                _ => {}
+            },
+            Message::Reset => {
+                self.duration = Duration::default();
+            }
+        }
+
+        Command::none()
+    }
+
+    fn subscriptions(&self) -> Subscription<Message> {
+        match self.state {
+            State::Idle => Subscription::none(),
+            State::Ticking { .. } => {
+                time::every(Duration::from_millis(10)).map(Message::Tick)
+            }
+        }
+    }
+
+    fn view(&mut self) -> Element<Message> {
+        const MINUTE: u64 = 60;
+        const HOUR: u64 = 60 * MINUTE;
+
+        let seconds = self.duration.as_secs();
+
+        let duration = Text::new(format!(
+            "{:0>2}:{:0>2}:{:0>2}.{:0>2}",
+            seconds / HOUR,
+            seconds / MINUTE,
+            seconds % MINUTE,
+            self.duration.subsec_millis() / 10,
+        ))
+        .width(Length::Shrink)
+        .size(40);
+
+        let button = |state, label, color: [f32; 3]| {
+            Button::new(
+                state,
+                Text::new(label)
+                    .color(Color::WHITE)
+                    .horizontal_alignment(HorizontalAlignment::Center),
+            )
+            .min_width(80)
+            .background(Background::Color(color.into()))
+            .border_radius(10)
+            .padding(10)
+        };
+
+        let toggle_button = {
+            let (label, color) = match self.state {
+                State::Idle => ("Start", [0.11, 0.42, 0.87]),
+                State::Ticking { .. } => ("Stop", [0.9, 0.4, 0.4]),
+            };
+
+            button(&mut self.toggle, label, color).on_press(Message::Toggle)
+        };
+
+        let reset_button = button(&mut self.reset, "Reset", [0.7, 0.7, 0.7])
+            .on_press(Message::Reset);
+
+        let controls = Row::new()
+            .width(Length::Shrink)
+            .spacing(20)
+            .push(toggle_button)
+            .push(reset_button);
+
+        let content = Column::new()
+            .width(Length::Shrink)
+            .align_items(Align::Center)
+            .spacing(20)
+            .push(duration)
+            .push(controls);
+
+        Container::new(content)
+            .width(Length::Fill)
+            .height(Length::Fill)
+            .center_x()
+            .center_y()
+            .into()
+    }
+}
+
+mod time {
+    pub fn every(
+        duration: std::time::Duration,
+    ) -> iced::Subscription<std::time::Instant> {
+        iced::Subscription::from_recipe(Every(duration))
+    }
+
+    struct Every(std::time::Duration);
+
+    impl<Input> iced_native::subscription::Recipe<iced_native::Hasher, Input>
+        for Every
+    {
+        type Output = std::time::Instant;
+
+        fn hash(&self, state: &mut iced_native::Hasher) {
+            use std::hash::Hash;
+
+            std::any::TypeId::of::<Self>().hash(state);
+        }
+
+        fn stream(
+            &self,
+            _input: Input,
+        ) -> futures::stream::BoxStream<'static, Self::Output> {
+            use futures::stream::StreamExt;
+
+            async_std::stream::interval(self.0)
+                .map(|_| std::time::Instant::now())
+                .boxed()
+        }
+    }
+}