//! A web runtime for Iced, targetting the DOM.
//!
//! `iced_web` takes [`iced_core`] and builds a WebAssembly runtime on top. It
//! achieves this by introducing a `Widget` trait that can be used to produce
//! VDOM nodes.
//!
//! The crate is currently a __very experimental__, simple abstraction layer
//! over [`dodrio`].
//!
//! [`iced_core`]: https://github.com/hecrj/iced/tree/master/core
//! [`dodrio`]: https://github.com/fitzgen/dodrio
//!
//! # Usage
//! The current build process is a bit involved, as [`wasm-pack`] does not
//! currently [support building binary crates](https://github.com/rustwasm/wasm-pack/issues/734).
//!
//! Therefore, we instead build using the `wasm32-unknown-unknown` target and
//! use the [`wasm-bindgen`] CLI to generate appropriate bindings.
//!
//! For instance, let's say we want to build the [`tour` example]:
//!
//! ```bash
//! cd examples
//! cargo build --package tour --target wasm32-unknown-unknown
//! wasm-bindgen ../target/wasm32-unknown-unknown/debug/tour.wasm --out-dir tour --web
//! ```
//!
//! Then, we need to create an `.html` file to load our application:
//!
//! ```html
//! <!DOCTYPE html>
//! <html>
//! <head>
//! <meta http-equiv="Content-type" content="text/html; charset=utf-8"/>
//! <meta name="viewport" content="width=device-width, initial-scale=1">
//! <title>Tour - Iced</title>
//! </head>
//! <body>
//! <script type="module">
//! import init from "./tour/tour.js";
//!
//! init('./tour/tour_bg.wasm');
//! </script>
//! </body>
//! </html>
//! ```
//!
//! Finally, we serve it using an HTTP server and access it with our browser.
//!
//! [`wasm-pack`]: https://github.com/rustwasm/wasm-pack
//! [`wasm-bindgen`]: https://github.com/rustwasm/wasm-bindgen
//! [`tour` example]: https://github.com/hecrj/iced/tree/0.1/examples/tour
#![deny(missing_docs)]
#![deny(missing_debug_implementations)]
#![deny(unused_results)]
#![forbid(unsafe_code)]
#![forbid(rust_2018_idioms)]
use dodrio::bumpalo;
use std::{cell::RefCell, rc::Rc};
mod bus;
mod element;
mod hasher;
pub mod css;
pub mod subscription;
pub mod widget;
pub use bus::Bus;
pub use css::Css;
pub use dodrio;
pub use element::Element;
pub use hasher::Hasher;
pub use iced_core::{
keyboard, mouse, Align, Background, Color, Font, HorizontalAlignment,
Length, Point, Rectangle, Size, Vector, VerticalAlignment,
};
pub use iced_futures::{executor, futures, Command};
pub use subscription::Subscription;
#[doc(no_inline)]
pub use widget::*;
#[doc(no_inline)]
pub use executor::Executor;
/// An interactive web application.
///
/// This trait is the main entrypoint of Iced. Once implemented, you can run
/// your GUI application by simply calling [`run`](#method.run). It will take
/// control of the `<title>` and the `<body>` of the document.
///
/// An [`Application`](trait.Application.html) can execute asynchronous actions
/// by returning a [`Command`](struct.Command.html) in some of its methods.
pub trait Application {
/// The [`Executor`] that will run commands and subscriptions.
type Executor: Executor;
/// The type of __messages__ your [`Application`] will produce.
type Message: Send;
/// The data needed to initialize your [`Application`].
type Flags;
/// Initializes the [`Application`].
///
/// 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.
fn new(flags: Self::Flags) -> (Self, Command<Self::Message>)
where
Self: Sized;
/// 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 widgets to display in the [`Application`].
///
/// These widgets can produce __messages__ based on user interaction.
fn view(&mut self) -> Element<'_, 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()
}
/// Runs the [`Application`].
fn run(flags: Self::Flags)
where
Self: 'static + Sized,
{
use futures::stream::StreamExt;
let window = web_sys::window().unwrap();
let document = window.document().unwrap();
let body = document.body().unwrap();
let (sender, receiver) =
iced_futures::futures::channel::mpsc::unbounded();
let mut runtime = iced_futures::Runtime::new(
Self::Executor::new().expect("Create executor"),
sender.clone(),
);
let (app, command) = runtime.enter(|| Self::new(flags));
let mut title = app.title();
document.set_title(&title);
runtime.spawn(command);
let application = Rc::new(RefCell::new(app));
let instance = Instance {
application: application.clone(),
bus: Bus::new(sender),
};
let vdom = dodrio::Vdom::new(&body, instance);
let event_loop = receiver.for_each(move |message| {
let (command, subscription) = runtime.enter(|| {
let command = application.borrow_mut().update(message);
let subscription = application.borrow().subscription();
(command, subscription)
});
let new_title = application.borrow().title();
runtime.spawn(command);
runtime.track(subscription);
if title != new_title {
document.set_title(&new_title);
title = new_title;
}
vdom.weak().schedule_render();
futures::future::ready(())
});
wasm_bindgen_futures::spawn_local(event_loop);
}
}
struct Instance<A: Application> {
application: Rc<RefCell<A>>,
bus: Bus<A::Message>,
}
impl<'a, A> dodrio::Render<'a> for Instance<A>
where
A: Application,
{
fn render(
&self,
context: &mut dodrio::RenderContext<'a>,
) -> dodrio::Node<'a> {
use dodrio::builder::*;
let mut ui = self.application.borrow_mut();
let element = ui.view();
let mut css = Css::new();
let node = element.widget.node(context.bump, &self.bus, &mut css);
div(context.bump)
.attr("style", "width: 100%; height: 100%")
.children(vec![css.node(context.bump), node])
.finish()
}
}
