` and the `<body>` of the /// document. /// /// An [`Application`] can execute asynchronous actions by returning a /// [`Task`] in some of its methods. /// /// 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/iced-rs/iced/tree/0.12/examples /// [`clock`]: https://github.com/iced-rs/iced/tree/0.12/examples/clock /// [`download_progress`]: https://github.com/iced-rs/iced/tree/0.12/examples/download_progress /// [`events`]: https://github.com/iced-rs/iced/tree/0.12/examples/events /// [`game_of_life`]: https://github.com/iced-rs/iced/tree/0.12/examples/game_of_life /// [`pokedex`]: https://github.com/iced-rs/iced/tree/0.12/examples/pokedex /// [`solar_system`]: https://github.com/iced-rs/iced/tree/0.12/examples/solar_system /// [`stopwatch`]: https://github.com/iced-rs/iced/tree/0.12/examples/stopwatch /// [`todos`]: https://github.com/iced-rs/iced/tree/0.12/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::advanced::Application; /// use iced::executor; /// use iced::{Task, Element, Settings, Theme, Renderer}; /// /// pub fn main() -> iced::Result { /// Hello::run(Settings::default()) /// } /// /// struct Hello; /// /// impl Application for Hello { /// type Executor = executor::Default; /// type Flags = (); /// type Message = (); /// type Theme = Theme; /// type Renderer = Renderer; /// /// fn new(_flags: ()) -> (Hello, Task<Self::Message>) { /// (Hello, Task::none()) /// } /// /// fn title(&self) -> String { /// String::from("A cool application") /// } /// /// fn update(&mut self, _message: Self::Message) -> Task<Self::Message> { /// Task::none() /// } /// /// fn view(&self) -> Element<Self::Message> { /// "Hello, world!".into() /// } /// } /// ``` pub trait Application: Sized where Self::Theme: DefaultStyle, { /// 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 theme of your [`Application`]. type Theme: Default; /// The renderer of your [`Application`]. type Renderer: text::Renderer + compositor::Default; /// 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 [`Task`] 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, Task<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 [`Task`] returned will be executed immediately in the background. fn update(&mut self, message: Self::Message) -> Task<Self::Message>; /// Returns the widgets to display in the [`Application`]. /// /// These widgets can produce __messages__ based on user interaction. fn view(&self) -> Element<'_, Self::Message, Self::Theme, Self::Renderer>; /// Returns the current [`Theme`] of the [`Application`]. /// /// [`Theme`]: Self::Theme fn theme(&self) -> Self::Theme { Self::Theme::default() } /// Returns the current [`Appearance`] of the [`Application`]. fn style(&self, theme: &Self::Theme) -> Appearance { theme.default_style() } /// 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 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 } /// 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, { #[allow(clippy::needless_update)] let renderer_settings = crate::graphics::Settings { default_font: settings.default_font, default_text_size: settings.default_text_size, antialiasing: if settings.antialiasing { Some(crate::graphics::Antialiasing::MSAAx4) } else { None }, ..crate::graphics::Settings::default() }; Ok(crate::shell::application::run::< Instance<Self>, Self::Executor, <Self::Renderer as compositor::Default>::Compositor, >(settings.into(), renderer_settings)?) } } struct Instance<A>(A) where A: Application, A::Theme: DefaultStyle; impl<A> crate::runtime::Program for Instance<A> where A: Application, A::Theme: DefaultStyle, { type Message = A::Message; type Theme = A::Theme; type Renderer = A::Renderer; fn update(&mut self, message: Self::Message) -> Task<Self::Message> { self.0.update(message) } fn view(&self) -> Element<'_, Self::Message, Self::Theme, Self::Renderer> { self.0.view() } } impl<A> application::Application for Instance<A> where A: Application, A::Theme: DefaultStyle, { type Flags = A::Flags; fn new(flags: Self::Flags) -> (Self, Task<A::Message>) { let (app, command) = A::new(flags); (Instance(app), command) } fn title(&self) -> String { self.0.title() } fn theme(&self) -> A::Theme { self.0.theme() } fn style(&self, theme: &A::Theme) -> Appearance { self.0.style(theme) } fn subscription(&self) -> Subscription<Self::Message> { self.0.subscription() } fn scale_factor(&self) -> f64 { self.0.scale

//! Build interactive cross-platform applications. use crate::core::text; use crate::graphics::compositor; use crate::shell::application; use crate::{Element, Executor, Settings, Subscription, Task}; pub use application::{Appearance, DefaultStyle}; /// 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 /// [`Task`] in some of its methods. /// /// 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/iced-rs/iced/tree/0.12/examples /// [`clock`]: https://github.com/iced-rs/iced/tree/0.12/examples/clock /// [`download_progress`]: https://github.com/iced-rs/iced/tree/0.12/examples/download_progress /// [`events`]: https://github.com/iced-rs/iced/tree/0.12/examples/events /// [`game_of_life`]: https://github.com/iced-rs/iced/tree/0.12/examples/game_of_life /// [`pokedex`]: https://github.com/iced-rs/iced/tree/0.12/examples/pokedex /// [`solar_system`]: https://github.com/iced-rs/iced/tree/0.12/examples/solar_system /// [`stopwatch`]: https://github.com/iced-rs/iced/tree/0.12/examples/stopwatch /// [`todos`]: https://github.com/iced-rs/iced/tree/0.12/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::advanced::Application; /// use iced::executor; /// use iced::{Task, Element, Settings, Theme, Renderer}; /// /// pub fn main() -> iced::Result { /// Hello::run(Settings::default()) /// } /// /// struct Hello; /// /// impl Application for Hello { /// type Executor = executor::Default; /// type Flags = (); /// type Message = (); /// type Theme = Theme; /// type Renderer = Renderer; /// /// fn new(_flags: ()) -> (Hello, Task<Self::Message>) { /// (Hello, Task::none()) /// } /// /// fn title(&self) -> String { /// String::from("A cool application") /// } /// /// fn update(&mut self, _message: Self::Message) -> Task<Self::Message> { /// Task::none() /// } /// /// fn view(&self) -> Element<Self::Message> { /// "Hello, world!".into() /// } /// } /// ``` pub trait Application: Sized where Self::Theme: DefaultStyle, { /// 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 theme of your [`Application`]. type Theme: Default; /// The renderer of your [`Application`]. type Renderer: text::Renderer + compositor::Default; /// 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 [`Task`] 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, Task<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 [`Task`] returned will be executed immediately in the background. fn update(&mut self, message: Self::Message) -> Task<Self::Message>; /// Returns the widgets to display in the [`Application`]. /// /// These widgets can produce __messages__ based on user interaction. fn view(&self) -> Element<'_, Self::Message, Self::Theme, Self::Renderer>; /// Returns the current [`Theme`] of the [`Application`]. /// /// [`Theme`]: Self::Theme fn theme(&self) -> Self::Theme { Self::Theme::default() } /// Returns the current [`Appearance`] of the [`Application`]. fn style(&self, theme: &Self::Theme) -> Appearance { theme.default_style() } /// 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 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 } /// 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, { #[allow(clippy::needless_update)] let renderer_settings = crate::graphics::Settings { default_font: settings.default_font, default_text_size: settings.default_text_size, antialiasing: if settings.antialiasing { Some(crate::graphics::Antialiasing::MSAAx4) } else { None }, ..crate::graphics::Settings::default() }; Ok(crate::shell::application::run::< Instance<Self>, Self::Executor, <Self::Renderer as compositor::Default>::Compositor, >(settings.into(), renderer_settings)?) } } struct Instance<A>(A) where A: Application, A::Theme: DefaultStyle; impl<A> crate::runtime::Program for Instance<A> where A: Application, A::Theme: DefaultStyle, { type Message = A::Message; type Theme = A::Theme; type Renderer = A::Renderer; fn update(&mut self, message: Self::Message) -> Task<Self::Message> { self.0.update(message) } fn view(&self) -> Element<'_, Self::Message, Self::Theme, Self::Renderer> { self.0.view() } } impl<A> application::Application for Instance<A> where A: Application, A::Theme: DefaultStyle, { type Flags = A::Flags; fn new(flags: Self::Flags) -> (Self, Task<A::Message>) { let (app, command) = A::new(flags); (Instance(app), command) } fn title(&self) -> String { self.0.title() } fn theme(&self) -> A::Theme { self.0.theme() } fn style(&self, theme: &A::Theme) -> Appearance { self.0.style(theme) } fn subscription(&self) -> Subscription<Self::Message> { self.0.subscription() } fn scale_factor(&self) -> f64 { self.0.scale_factor() } }