feat(widget): add calendar widget

examples/application/src/main.rs

@@ -32,7 +32,7 @@ impl Page {
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     tracing_subscriber::fmt::init();
     let _ = tracing_log::LogTracer::init();
- 
+
     let input = vec![
         (Page::Page1, "🖖 Hello from libcosmic.".into()),
         (Page::Page2, "🌟 This is an example application.".into()),
@@ -124,8 +124,7 @@ impl cosmic::Application for App {
         let page_content = self
             .nav_model
             .active_data::<String>()
-            .map(String::as_str)
-            .unwrap_or("No page selected");
+            .map_or("No page selected", String::as_str);
 
         let text = cosmic::widget::text(page_content);
 

examples/calendar/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "calendar"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+chrono = "0.4.35"
+
+[dependencies.libcosmic]
+path = "../../"
+default-features = false
+features = ["debug", "winit", "tokio", "xdg-portal", "wgpu"]

examples/calendar/src/main.rs

@@ -0,0 +1,136 @@
+// Copyright 2024 System76 <info@system76.com>
+// SPDX-License-Identifier: MPL-2.0
+
+//! Calendar widget example
+
+use chrono::{Datelike, Days, Local, Months, NaiveDate};
+use cosmic::app::{Command, Core, Settings};
+use cosmic::{executor, iced, ApplicationExt, Element};
+
+/// Runs application with these settings
+#[rustfmt::skip]
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    cosmic::app::run::<App>(Settings::default(), ())?;
+
+    Ok(())
+}
+
+/// Messages that are used specifically by our [`App`].
+#[derive(Clone, Debug)]
+pub enum Message {
+    PrevMonth,
+    NextMonth,
+    DaySelected(u32),
+}
+
+/// The [`App`] stores application-specific state.
+pub struct App {
+    core: Core,
+    date_selected: NaiveDate,
+}
+
+/// Implement [`cosmic::Application`] to integrate with COSMIC.
+impl cosmic::Application for App {
+    /// Default async executor to use with the app.
+    type Executor = executor::Default;
+
+    /// Argument received [`cosmic::Application::new`].
+    type Flags = ();
+
+    /// Message type specific to our [`App`].
+    type Message = Message;
+
+    /// The unique application ID to supply to the window manager.
+    const APP_ID: &'static str = "org.cosmic.AppDemo";
+
+    fn core(&self) -> &Core {
+        &self.core
+    }
+
+    fn core_mut(&mut self) -> &mut Core {
+        &mut self.core
+    }
+
+    /// Creates the application, and optionally emits command on initialize.
+    fn init(core: Core, _input: Self::Flags) -> (Self, Command<Self::Message>) {
+        let now = Local::now();
+
+        let mut app = App {
+            core,
+            date_selected: NaiveDate::from(now.naive_local()),
+        };
+
+        let command = app.update_title();
+
+        (app, command)
+    }
+
+    /// Handle application events here.
+    fn update(&mut self, message: Self::Message) -> Command<Self::Message> {
+        match message {
+            Message::DaySelected(day) => {
+                let current = self.date_selected.day();
+
+                let new_date = if current < day {
+                    self.date_selected
+                        .checked_add_days(Days::new((day - current) as u64))
+                } else if current > day {
+                    self.date_selected
+                        .checked_sub_days(Days::new((current - day) as u64))
+                } else {
+                    None
+                };
+
+                if let Some(new) = new_date {
+                    self.date_selected = new;
+                }
+            }
+            Message::PrevMonth => {
+                self.date_selected = self
+                    .date_selected
+                    .checked_sub_months(Months::new(1))
+                    .expect("valid naivedate");
+            }
+            Message::NextMonth => {
+                self.date_selected = self
+                    .date_selected
+                    .checked_add_months(Months::new(1))
+                    .expect("valid naivedate");
+            }
+        }
+
+        Command::none()
+    }
+
+    /// Creates a view after each update.
+    fn view(&self) -> Element<Self::Message> {
+        let mut content = cosmic::widget::column().spacing(12);
+
+        let calendar = cosmic::widget::calendar(
+            &self.date_selected,
+            Message::PrevMonth,
+            Message::NextMonth,
+            |day| Message::DaySelected(day),
+        );
+
+        content = content.push(cosmic::widget::container(calendar).width(350));
+
+        let centered = cosmic::widget::container(content)
+            .width(iced::Length::Fill)
+            .height(iced::Length::Shrink)
+            .align_x(iced::alignment::Horizontal::Center)
+            .align_y(iced::alignment::Vertical::Center);
+
+        Element::from(centered)
+    }
+}
+
+impl App
+where
+    Self: cosmic::Application,
+{
+    fn update_title(&mut self) -> Command<Message> {
+        self.set_header_title(String::from("Calendar Demo"));
+        self.set_window_title(String::from("Calendar Demo"))
+    }
+}