diff options
Diffstat (limited to 'src/multi_window.rs')
| -rw-r--r-- | src/multi_window.rs | 256 |
1 files changed, 254 insertions, 2 deletions
diff --git a/src/multi_window.rs b/src/multi_window.rs index 5b7a00b4..bd57a746 100644 --- a/src/multi_window.rs +++ b/src/multi_window.rs @@ -1,4 +1,256 @@ //! Leverage multi-window support in your application. -mod application; +use crate::window; +use crate::{Command, Element, Executor, Settings, Subscription}; -pub use application::Application; +pub use crate::application::{default, Appearance, Style}; + +/// An interactive cross-platform multi-window 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 windows. +/// - On the web, it will take control of the `<title>` and the `<body>` of the +/// document and display only the contents of the `window::Id::MAIN` window. +/// +/// 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 +/// See the `examples/multi-window` example to see this multi-window `Application` trait in action. +/// +/// ## 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, window}; +/// use iced::{Command, Element, Settings, Theme}; +/// use iced::multi_window::{self, Application}; +/// +/// pub fn main() -> iced::Result { +/// Hello::run(Settings::default()) +/// } +/// +/// struct Hello; +/// +/// impl multi_window::Application for Hello { +/// type Executor = executor::Default; +/// type Flags = (); +/// type Message = (); +/// type Theme = Theme; +/// +/// fn new(_flags: ()) -> (Hello, Command<Self::Message>) { +/// (Hello, Command::none()) +/// } +/// +/// fn title(&self, _window: window::Id) -> String { +/// String::from("A cool application") +/// } +/// +/// fn update(&mut self, _message: Self::Message) -> Command<Self::Message> { +/// Command::none() +/// } +/// +/// fn view(&self, _window: window::Id) -> Element<Self::Message> { +/// "Hello, world!".into() +/// } +/// } +/// ``` +/// +/// [`Sandbox`]: crate::Sandbox +pub trait Application: Sized +where + Style<Self::Theme>: Default, +{ + /// 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 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 `window` of the [`Application`]. + /// + /// This title can be dynamic! The runtime will automatically update the + /// title of your window when necessary. + fn title(&self, window: window::Id) -> 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 widgets to display in the `window` of the [`Application`]. + /// + /// These widgets can produce __messages__ based on user interaction. + fn view( + &self, + window: window::Id, + ) -> Element<'_, Self::Message, Self::Theme, crate::Renderer>; + + /// Returns the current [`Theme`] of the `window` of the [`Application`]. + /// + /// [`Theme`]: Self::Theme + #[allow(unused_variables)] + fn theme(&self, window: window::Id) -> Self::Theme { + Self::Theme::default() + } + + /// Returns the current `Style` of the [`Theme`]. + /// + /// [`Theme`]: Self::Theme + fn style(&self, theme: &Self::Theme) -> Appearance { + Style::default().resolve(theme) + } + + /// 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 `window` 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`. + #[allow(unused_variables)] + fn scale_factor(&self, window: window::Id) -> f64 { + 1.0 + } + + /// Runs the multi-window [`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::renderer::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::renderer::Settings::default() + }; + + Ok(crate::shell::multi_window::run::< + Instance<Self>, + Self::Executor, + crate::renderer::Compositor, + >(settings.into(), renderer_settings)?) + } +} + +struct Instance<A>(A) +where + A: Application, + Style<A::Theme>: Default; + +impl<A> crate::runtime::multi_window::Program for Instance<A> +where + A: Application, + Style<A::Theme>: Default, +{ + type Message = A::Message; + type Theme = A::Theme; + type Renderer = crate::Renderer; + + fn update(&mut self, message: Self::Message) -> Command<Self::Message> { + self.0.update(message) + } + + fn view( + &self, + window: window::Id, + ) -> Element<'_, Self::Message, Self::Theme, Self::Renderer> { + self.0.view(window) + } +} + +impl<A> crate::shell::multi_window::Application for Instance<A> +where + A: Application, + Style<A::Theme>: Default, +{ + 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, window: window::Id) -> String { + self.0.title(window) + } + + fn theme(&self, window: window::Id) -> A::Theme { + self.0.theme(window) + } + + fn style(&self, theme: &Self::Theme) -> Appearance { + self.0.style(theme) + } + + fn subscription(&self) -> Subscription<Self::Message> { + self.0.subscription() + } + + fn scale_factor(&self, window: window::Id) -> f64 { + self.0.scale_factor(window) + } +} |