` and the `<body>` of the /// document. /// /// An [`Application`] can execute asynchronous actions by returning a /// [`Command`] in some of its methods. If you do not intend to perform any /// background work in your program, the [`Sandbox`] trait offers a simplified /// interface. /// /// When using an [`Application`] with the `debug` feature enabled, a debug view /// can be toggled by pressing `F12`. /// /// # Examples /// [The repository has a bunch of examples] that use the [`Application`] trait: /// /// - [`clock`], an application that uses the [`Canvas`] widget to draw a clock /// and its hands to display the current time. /// - [`download_progress`], a basic application that asynchronously downloads /// a dummy file of 100 MB and tracks the download progress. /// - [`events`], a log of native events displayed using a conditional /// [`Subscription`]. /// - [`game_of_life`], an interactive version of the [Game of Life], invented /// by [John Horton Conway]. /// - [`pokedex`], an application that displays a random Pokédex entry (sprite /// included!) by using the [PokéAPI]. /// - [`solar_system`], an animated solar system drawn using the [`Canvas`] widget /// and showcasing how to compose different transforms. /// - [`stopwatch`], a watch with start/stop and reset buttons showcasing how /// to listen to time. /// - [`todos`], a todos tracker inspired by [TodoMVC]. /// /// [The repository has a bunch of examples]: https://github.com/hecrj/iced/tree/0.3/examples /// [`clock`]: https://github.com/hecrj/iced/tree/0.3/examples/clock /// [`download_progress`]: https://github.com/hecrj/iced/tree/0.3/examples/download_progress /// [`events`]: https://github.com/hecrj/iced/tree/0.3/examples/events /// [`game_of_life`]: https://github.com/hecrj/iced/tree/0.3/examples/game_of_life /// [`pokedex`]: https://github.com/hecrj/iced/tree/0.3/examples/pokedex /// [`solar_system`]: https://github.com/hecrj/iced/tree/0.3/examples/solar_system /// [`stopwatch`]: https://github.com/hecrj/iced/tree/0.3/examples/stopwatch /// [`todos`]: https://github.com/hecrj/iced/tree/0.3/examples/todos /// [`Sandbox`]: crate::Sandbox /// [`Canvas`]: crate::widget::Canvas /// [PokéAPI]: https://pokeapi.co/ /// [TodoMVC]: http://todomvc.com/ /// /// ## A simple "Hello, world!" /// /// If you just want to get started, here is a simple [`Application`] that /// says "Hello, world!": /// /// ```no_run /// use iced::{executor, Application, Command, Element, Settings, Text}; /// /// pub fn main() -> iced::Result { /// Hello::run(Settings::default()) /// } /// /// struct Hello; /// /// impl Application for Hello { /// type Executor = executor::Default; /// type Message = (); /// type Flags = (); /// /// fn new(_flags: ()) -> (Hello, Command<Self::Message>) { /// (Hello, Command::none()) /// } /// /// fn title(&self) -> String { /// String::from("A cool application") /// } /// /// fn update(&mut self, _message: Self::Message) -> Command<Self::Message> { /// Command::none() /// } /// /// fn view(&mut self) -> Element<Self::Message> { /// Text::new("Hello, world!").into() /// } /// } /// ``` pub trait Application: Sized { /// The [`Executor`] that will run commands and subscriptions. /// /// The [default executor] can be a good starting point! /// /// [`Executor`]: Self::Executor /// [default executor]: crate::executor::Default type Executor: Executor; /// The type of __messages__ your [`Application`] will produce. type Message: std::fmt::Debug + Send; /// The data needed to initialize your [`Application`]. type Flags; /// Initializes the [`Application`] with the flags provided to /// [`run`] as part of the [`Settings`]. /// /// Here is where you should return the initial state of your app. /// /// Additionally, you can return a [`Command`] if you need to perform some /// async action in the background on startup. This is useful if you want to /// load state from a file, perform an initial HTTP request, etc. /// /// [`run`]: Self::run fn new(flags: Self::Flags) -> (Self, Command<Self::Message>); /// Returns the current title of the [`Application`]. /// /// This title can be dynamic! The runtime will automatically update the /// title of your application when necessary. fn title(&self) -> String; /// Handles a __message__ and updates the state of the [`Application`]. /// /// This is where you define your __update logic__. All the __messages__, /// produced by either user interactions or commands, will be handled by /// this method. /// /// Any [`Command`] returned will be executed immediately in the background. fn update(&mut self, message: Self::Message) -> Command<Self::Message>; /// Returns the event [`Subscription`] for the current state of the /// application. /// /// A [`Subscription`] will be kept alive as long as you keep returning it, /// and the __messages__ produced will be handled by /// [`update`](#tymethod.update). /// /// By default, this method returns an empty [`Subscription`]. fn subscription(&self) -> Subscription<Self::Message> { Subscription::none() } /// Returns the widgets to display in the [`Application`]. /// /// These widgets can produce __messages__ based on user interaction. fn view(&mut self) -> Element<'_, Self::Message>; /// Returns the current [`Application`] mode. /// /// The runtime will automatically transition your application if a new mode /// is returned. /// /// Currently, the mode only has an effect in native platforms. /// /// By default, an application will run in windowed mode. fn mode(&self) -> window::Mode { window::Mode::Windowed } /// Returns the background color of the [`Application`]. /// /// By default, it returns [`Color::WHITE`]. fn background_color(&self) -> Color { Color::WHITE } /// Returns the scale factor of the [`Application`]. /// /// It can be used to dynamically control the size of the UI at runtime /// (i.e. zooming). /// /// For instance, a scale factor of `2.0` will make widgets twice as big, /// while a scale factor of `0.5` will shrink them to half their size. /// /// By default, it returns `1.0`. fn scale_factor(&self) -> f64 { 1.0 } /// Returns whether the [`Application`] should be terminated. /// /// By default, it returns `false`. fn should_exit(&self) -> bool { false } /// Runs the [`Application`]. /// /// On native platforms, this method will take control of the current thread /// until the [`Application`] exits. /// /// On the web platform, this method __will NOT return__ unless there is an /// [`Error`] during startup. /// /// [`Error`]: crate::Error fn run(settings: Settings<Self::Flags>) -> crate::Result where Self: 'static, { let renderer_settings = crate::renderer::Settings { default_font: settings.default_font, default_text_size: settings.default_text_size, text_multithreading: settings.text_multithreading, antialiasing: if settings.antialiasing { Some(crate::renderer::settings::Antialiasing::MSAAx4) } else { None }, ..crate::renderer::Settings::from_env() }; Ok(crate::runtime::application::run::< Instance<Self>, Self::Executor, crate::renderer::window::Compositor, >(settings.into(), renderer_settings)?) } } struct Instance<A: Application>(A); impl<A> iced_winit::Program for Instance<A> where A: Application, { type Renderer = crate::renderer::Renderer; type Message = A::Message; fn update(&mut self, message: Self::Message) -> Command<Self::Message> { self.0.update(message) } fn view(&mut self) -> Element<'_, Self::Message> { self.0.view() } } impl<A> crate::runtime::Application for Instance<A> where A: Application, { type Flags = A::Flags; fn new(flags: Self::Flags) -> (Self, Command<A::Message>) { let (app, command) = A::new(flags); (Instance(app), command) } fn title(&self) -> String { self.0.title() } fn mode(&self) -> iced_winit::Mode { match self.0.mode() { window::Mode::Windowed => iced_winit::Mode::Windowed, window::Mode::Fullscreen => iced_winit::Mode::Fullscreen, window::Mode::Hidden => iced_winit::Mode::Hidden, } } fn subscription(&self) -> Subscription<Self::Message> { self.0.subscription() } fn background_color(&self) -> Color { self.0.background_color() } fn scale_factor(&self) -> f64 { self.0.scale_factor() } fn should_exit(&self) -> bool { self.0.should

use crate::window; use crate::{Color, Command, Element, Executor, Settings, Subscription}; /// An interactive cross-platform application. /// /// This trait is the main entrypoint of Iced. Once implemented, you can run /// your GUI application by simply calling [`run`](#method.run). /// /// - On native platforms, it will run in its own window. /// - On the web, it will take control of the `` and the `<body>` of the /// document. /// /// An [`Application`] can execute asynchronous actions by returning a /// [`Command`] in some of its methods. If you do not intend to perform any /// background work in your program, the [`Sandbox`] trait offers a simplified /// interface. /// /// When using an [`Application`] with the `debug` feature enabled, a debug view /// can be toggled by pressing `F12`. /// /// # Examples /// [The repository has a bunch of examples] that use the [`Application`] trait: /// /// - [`clock`], an application that uses the [`Canvas`] widget to draw a clock /// and its hands to display the current time. /// - [`download_progress`], a basic application that asynchronously downloads /// a dummy file of 100 MB and tracks the download progress. /// - [`events`], a log of native events displayed using a conditional /// [`Subscription`]. /// - [`game_of_life`], an interactive version of the [Game of Life], invented /// by [John Horton Conway]. /// - [`pokedex`], an application that displays a random Pokédex entry (sprite /// included!) by using the [PokéAPI]. /// - [`solar_system`], an animated solar system drawn using the [`Canvas`] widget /// and showcasing how to compose different transforms. /// - [`stopwatch`], a watch with start/stop and reset buttons showcasing how /// to listen to time. /// - [`todos`], a todos tracker inspired by [TodoMVC]. /// /// [The repository has a bunch of examples]: https://github.com/hecrj/iced/tree/0.3/examples /// [`clock`]: https://github.com/hecrj/iced/tree/0.3/examples/clock /// [`download_progress`]: https://github.com/hecrj/iced/tree/0.3/examples/download_progress /// [`events`]: https://github.com/hecrj/iced/tree/0.3/examples/events /// [`game_of_life`]: https://github.com/hecrj/iced/tree/0.3/examples/game_of_life /// [`pokedex`]: https://github.com/hecrj/iced/tree/0.3/examples/pokedex /// [`solar_system`]: https://github.com/hecrj/iced/tree/0.3/examples/solar_system /// [`stopwatch`]: https://github.com/hecrj/iced/tree/0.3/examples/stopwatch /// [`todos`]: https://github.com/hecrj/iced/tree/0.3/examples/todos /// [`Sandbox`]: crate::Sandbox /// [`Canvas`]: crate::widget::Canvas /// [PokéAPI]: https://pokeapi.co/ /// [TodoMVC]: http://todomvc.com/ /// /// ## A simple "Hello, world!" /// /// If you just want to get started, here is a simple [`Application`] that /// says "Hello, world!": /// /// ```no_run /// use iced::{executor, Application, Command, Element, Settings, Text}; /// /// pub fn main() -> iced::Result { /// Hello::run(Settings::default()) /// } /// /// struct Hello; /// /// impl Application for Hello { /// type Executor = executor::Default; /// type Message = (); /// type Flags = (); /// /// fn new(_flags: ()) -> (Hello, Command<Self::Message>) { /// (Hello, Command::none()) /// } /// /// fn title(&self) -> String { /// String::from("A cool application") /// } /// /// fn update(&mut self, _message: Self::Message) -> Command<Self::Message> { /// Command::none() /// } /// /// fn view(&mut self) -> Element<Self::Message> { /// Text::new("Hello, world!").into() /// } /// } /// ``` pub trait Application: Sized { /// The [`Executor`] that will run commands and subscriptions. /// /// The [default executor] can be a good starting point! /// /// [`Executor`]: Self::Executor /// [default executor]: crate::executor::Default type Executor: Executor; /// The type of __messages__ your [`Application`] will produce. type Message: std::fmt::Debug + Send; /// The data needed to initialize your [`Application`]. type Flags; /// Initializes the [`Application`] with the flags provided to /// [`run`] as part of the [`Settings`]. /// /// Here is where you should return the initial state of your app. /// /// Additionally, you can return a [`Command`] if you need to perform some /// async action in the background on startup. This is useful if you want to /// load state from a file, perform an initial HTTP request, etc. /// /// [`run`]: Self::run fn new(flags: Self::Flags) -> (Self, Command<Self::Message>); /// Returns the current title of the [`Application`]. /// /// This title can be dynamic! The runtime will automatically update the /// title of your application when necessary. fn title(&self) -> String; /// Handles a __message__ and updates the state of the [`Application`]. /// /// This is where you define your __update logic__. All the __messages__, /// produced by either user interactions or commands, will be handled by /// this method. /// /// Any [`Command`] returned will be executed immediately in the background. fn update(&mut self, message: Self::Message) -> Command<Self::Message>; /// Returns the event [`Subscription`] for the current state of the /// application. /// /// A [`Subscription`] will be kept alive as long as you keep returning it, /// and the __messages__ produced will be handled by /// [`update`](#tymethod.update). /// /// By default, this method returns an empty [`Subscription`]. fn subscription(&self) -> Subscription<Self::Message> { Subscription::none() } /// Returns the widgets to display in the [`Application`]. /// /// These widgets can produce __messages__ based on user interaction. fn view(&mut self) -> Element<'_, Self::Message>; /// Returns the current [`Application`] mode. /// /// The runtime will automatically transition your application if a new mode /// is returned. /// /// Currently, the mode only has an effect in native platforms. /// /// By default, an application will run in windowed mode. fn mode(&self) -> window::Mode { window::Mode::Windowed } /// Returns the background color of the [`Application`]. /// /// By default, it returns [`Color::WHITE`]. fn background_color(&self) -> Color { Color::WHITE } /// Returns the scale factor of the [`Application`]. /// /// It can be used to dynamically control the size of the UI at runtime /// (i.e. zooming). /// /// For instance, a scale factor of `2.0` will make widgets twice as big, /// while a scale factor of `0.5` will shrink them to half their size. /// /// By default, it returns `1.0`. fn scale_factor(&self) -> f64 { 1.0 } /// Returns whether the [`Application`] should be terminated. /// /// By default, it returns `false`. fn should_exit(&self) -> bool { false } /// Runs the [`Application`]. /// /// On native platforms, this method will take control of the current thread /// until the [`Application`] exits. /// /// On the web platform, this method __will NOT return__ unless there is an /// [`Error`] during startup. /// /// [`Error`]: crate::Error fn run(settings: Settings<Self::Flags>) -> crate::Result where Self: 'static, { let renderer_settings = crate::renderer::Settings { default_font: settings.default_font, default_text_size: settings.default_text_size, text_multithreading: settings.text_multithreading, antialiasing: if settings.antialiasing { Some(crate::renderer::settings::Antialiasing::MSAAx4) } else { None }, ..crate::renderer::Settings::from_env() }; Ok(crate::runtime::application::run::< Instance<Self>, Self::Executor, crate::renderer::window::Compositor, >(settings.into(), renderer_settings)?) } } struct Instance<A: Application>(A); impl<A> iced_winit::Program for Instance<A> where A: Application, { type Renderer = crate::renderer::Renderer; type Message = A::Message; fn update(&mut self, message: Self::Message) -> Command<Self::Message> { self.0.update(message) } fn view(&mut self) -> Element<'_, Self::Message> { self.0.view() } } impl<A> crate::runtime::Application for Instance<A> where A: Application, { type Flags = A::Flags; fn new(flags: Self::Flags) -> (Self, Command<A::Message>) { let (app, command) = A::new(flags); (Instance(app), command) } fn title(&self) -> String { self.0.title() } fn mode(&self) -> iced_winit::Mode { match self.0.mode() { window::Mode::Windowed => iced_winit::Mode::Windowed, window::Mode::Fullscreen => iced_winit::Mode::Fullscreen, window::Mode::Hidden => iced_winit::Mode::Hidden, } } fn subscription(&self) -> Subscription<Self::Message> { self.0.subscription() } fn background_color(&self) -> Color { self.0.background_color() } fn scale_factor(&self) -> f64 { self.0.scale_factor() } fn should_exit(&self) -> bool { self.0.should_exit() } }