//! 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 --example tour --target wasm32-unknown-unknown
//! wasm-bindgen ../target/wasm32-unknown-unknown/debug/examples/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"/>
//! <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/blob/master/examples/tour.rs
#![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 style;
pub mod subscription;
pub mod widget;
pub use bus::Bus;
pub use dodrio;
pub use element::Element;
pub use hasher::Hasher;
pub use iced_core::{
Align, Background, Color, Font, HorizontalAlignment, Length, Vector,
VerticalAlignment,
};
pub use iced_futures::{executor, futures, Command};
pub use style::Style;
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 type of __messages__ your [`Application`] will produce.
///
/// [`Application`]: trait.Application.html
type Message;
/// Initializes the [`Application`].
///
/// Here is where you should return the initial state of your app.
///
/// Additionally, you can return a [`Command`](struct.Command.html) 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.
///
/// [`Application`]: trait.Application.html
fn new() -> (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.
///
/// [`Application`]: trait.Application.html
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.
///
/// [`Application`]: trait.Application.html
/// [`Command`]: struct.Command.html
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.
///
/// [`Application`]: trait.Application.html
fn view(&mut self) -> Element<'_, Self::Message>;
/// Runs the [`Application`].
///
/// [`Application`]: trait.Application.html
fn run()
where
Self: 'static + Sized,
{
let (app, command) = Self::new();
let instance = Instance::new(app);
instance.run(command);
}
}
struct Instance<Message> {
title: String,
ui: Rc<RefCell<Box<dyn Application<Message = Message>>>>,
vdom: Rc<RefCell<Option<dodrio::VdomWeak>>>,
}
impl<Message> Clone for Instance<Message> {
fn clone(&self) -> Self {
Self {
title: self.title.clone(),
ui: Rc::clone(&self.ui),
vdom: Rc::clone(&self.vdom),
}
}
}
impl<Message> Instance<Message>
where
Message: 'static,
{
fn new(ui: impl Application<Message = Message> + 'static) -> Self {
Self {
title: ui.title(),
ui: Rc::new(RefCell::new(Box::new(ui))),
vdom: Rc::new(RefCell::new(None)),
}
}
fn update(&mut self, message: Message) {
let command = self.ui.borrow_mut().update(message);
let title = self.ui.borrow().title();
self.spawn(command);
let window = web_sys::window().unwrap();
let document = window.document().unwrap();
if self.title != title {
document.set_title(&title);
self.title = title;
}
}
fn spawn(&mut self, command: Command<Message>) {
use futures::FutureExt;
for future in command.futures() {
let mut instance = self.clone();
let future = future.map(move |message| {
instance.update(message);
if let Some(ref vdom) = *instance.vdom.borrow() {
vdom.schedule_render();
}
});
wasm_bindgen_futures::spawn_local(future);
}
}
fn run(mut self, command: Command<Message>) {
let window = web_sys::window().unwrap();
let document = window.document().unwrap();
document.set_title(&self.title);
let body = document.body().unwrap();
let weak = self.vdom.clone();
self.spawn(command);
let vdom = dodrio::Vdom::new(&body, self);
*weak.borrow_mut() = Some(vdom.weak());
vdom.forget();
}
}
impl<Message> dodrio::Render for Instance<Message>
where
Message: 'static,
{
fn render<'a, 'bump>(
&'a self,
bump: &'bump bumpalo::Bump,
) -> dodrio::Node<'bump>
where
'a: 'bump,
{
use dodrio::builder::*;
let mut ui = self.ui.borrow_mut();
let element = ui.view();
let mut style_sheet = style::Sheet::new();
let node = element.widget.node(bump, &Bus::new(), &mut style_sheet);
div(bump)
.attr("style", "width: 100%; height: 100%")
.children(vec![style_sheet.node(bump), node])
.finish()
}
}
