egui/example_wasm/src/lib.rs
2020-07-18 18:00:05 +02:00

345 lines
12 KiB
Rust

#![deny(warnings)]
#![warn(clippy::all)]
use egui::{examples::ExampleApp, label, widgets::Separator, Align, RawInput, TextStyle, *};
use wasm_bindgen::prelude::*;
// ----------------------------------------------------------------------------
/// Data gathered between frames.
/// Is translated to `egui::RawInput` at the start of each frame.
#[derive(Default)]
pub struct WebInput {
pub mouse_pos: Option<Pos2>,
pub mouse_down: bool, // TODO: which button
pub is_touch: bool,
pub scroll_delta: Vec2,
pub events: Vec<Event>,
}
impl WebInput {
pub fn new_frame(&mut self) -> egui::RawInput {
egui::RawInput {
mouse_down: self.mouse_down,
mouse_pos: self.mouse_pos,
scroll_delta: std::mem::take(&mut self.scroll_delta),
screen_size: egui_web::screen_size().unwrap(),
pixels_per_point: Some(egui_web::pixels_per_point()),
time: egui_web::now_sec(),
seconds_since_midnight: Some(egui_web::seconds_since_midnight()),
events: std::mem::take(&mut self.events),
}
}
}
// ----------------------------------------------------------------------------
pub struct State {
egui_web: egui_web::EguiWeb,
web_input: WebInput,
example_app: ExampleApp,
}
impl State {
fn new(canvas_id: &str) -> Result<State, JsValue> {
Ok(State {
egui_web: egui_web::EguiWeb::new(canvas_id)?,
web_input: Default::default(),
example_app: Default::default(),
})
}
/// id of the canvas html element containing the rendering
pub fn canvas_id(&self) -> &str {
self.egui_web.canvas_id()
}
fn run(&mut self, raw_input: RawInput, web_location_hash: &str) -> Result<Output, JsValue> {
let mut ui = self.egui_web.begin_frame(raw_input);
self.ui(&mut ui, web_location_hash);
self.egui_web.end_frame()
}
fn ui(&mut self, ui: &mut egui::Ui, web_location_hash: &str) {
self.example_app.ui(ui, web_location_hash);
let mut ui = ui.centered_column(ui.available().width().min(480.0));
ui.set_layout(Layout::vertical(Align::Min));
ui.add(label!("Egui!").text_style(TextStyle::Heading));
ui.label("Egui is an immediate mode GUI written in Rust, compiled to WebAssembly, rendered with WebGL.");
ui.label(
"Everything you see is rendered as textured triangles. There is no DOM. There are no HTML elements."
);
ui.label("This is not JavaScript. This is Rust, running at 60 FPS. This is the web page, reinvented with game tech.");
ui.label("This is also work in progress, and not ready for production... yet :)");
ui.horizontal(|ui| {
ui.label("Project home page:");
ui.hyperlink("https://github.com/emilk/emigui/");
});
ui.add(Separator::new());
ui.label("WebGl painter info:");
ui.indent("webgl region id", |ui| {
ui.label(self.egui_web.painter_debug_info());
});
ui.add(
label!(
"CPU usage: {:.2} ms (excludes painting)",
1e3 * self.egui_web.cpu_usage()
)
.text_style(TextStyle::Monospace),
);
ui.add(label!("FPS: {:.1}", self.egui_web.fps()).text_style(TextStyle::Monospace));
}
}
// ----------------------------------------------------------------------------
use parking_lot::Mutex;
use std::sync::Arc;
#[wasm_bindgen]
#[derive(Clone)]
pub struct StateRef(Arc<Mutex<State>>);
/// If true, paint at full framerate always.
/// If false, only paint on input.
/// TODO: if this is turned off we must turn off animations too (which hasn't been implemented yet).
const ANIMATION_FRAME: bool = true;
#[wasm_bindgen]
pub fn start(canvas_id: &str) -> Result<StateRef, JsValue> {
let state = State::new(canvas_id)?;
let state = StateRef(Arc::new(Mutex::new(state)));
install_canvas_events(&state)?;
install_document_events(&state)?;
paint_and_schedule(state.clone())?;
Ok(state)
}
fn paint_and_schedule(state: StateRef) -> Result<(), JsValue> {
paint(&mut state.0.lock())?;
if ANIMATION_FRAME {
request_animation_frame(state)?;
}
Ok(())
}
fn request_animation_frame(state: StateRef) -> Result<(), JsValue> {
use wasm_bindgen::JsCast;
let window = web_sys::window().unwrap();
let closure = Closure::once(move || paint_and_schedule(state));
window.request_animation_frame(closure.as_ref().unchecked_ref())?;
closure.forget(); // We must forget it, or else the callback is canceled on drop
Ok(())
}
fn paint(state: &mut State) -> Result<(), JsValue> {
egui_web::resize_to_screen_size(state.canvas_id());
let raw_input = state.web_input.new_frame();
let web_location_hash = egui_web::location_hash().unwrap_or_default();
let output = state.run(raw_input, &web_location_hash)?;
egui_web::handle_output(&output);
Ok(())
}
fn invalidate(state: &mut State) -> Result<(), JsValue> {
if ANIMATION_FRAME {
Ok(()) // No need to invalidate - we repaint all the time
} else {
paint(state) // TODO: schedule repaint instead?
}
}
fn install_document_events(state: &StateRef) -> Result<(), JsValue> {
use wasm_bindgen::JsCast;
let document = web_sys::window().unwrap().document().unwrap();
{
// keydown
let state = state.clone();
let closure = Closure::wrap(Box::new(move |event: web_sys::KeyboardEvent| {
let mut state = state.0.lock();
let key = event.key();
if let Some(key) = egui_web::translate_key(&key) {
state
.web_input
.events
.push(Event::Key { key, pressed: true });
} else {
state.web_input.events.push(Event::Text(key));
}
invalidate(&mut state).unwrap();
}) as Box<dyn FnMut(_)>);
document.add_event_listener_with_callback("keydown", closure.as_ref().unchecked_ref())?;
closure.forget();
}
{
// keyup
let state = state.clone();
let closure = Closure::wrap(Box::new(move |event: web_sys::KeyboardEvent| {
let mut state = state.0.lock();
let key = event.key();
if let Some(key) = egui_web::translate_key(&key) {
state.web_input.events.push(Event::Key {
key,
pressed: false,
});
invalidate(&mut state).unwrap();
}
}) as Box<dyn FnMut(_)>);
document.add_event_listener_with_callback("keyup", closure.as_ref().unchecked_ref())?;
closure.forget();
}
for event_name in &["load", "pagehide", "pageshow", "resize"] {
let state = state.clone();
let closure = Closure::wrap(Box::new(move || {
invalidate(&mut state.0.lock()).unwrap();
}) as Box<dyn FnMut()>);
document.add_event_listener_with_callback(event_name, closure.as_ref().unchecked_ref())?;
closure.forget();
}
Ok(())
}
fn install_canvas_events(state: &StateRef) -> Result<(), JsValue> {
use egui_web::pos_from_mouse_event;
use wasm_bindgen::JsCast;
let canvas = egui_web::canvas_element(state.0.lock().canvas_id()).unwrap();
{
let event_name = "mousedown";
let state = state.clone();
let closure = Closure::wrap(Box::new(move |event: web_sys::MouseEvent| {
let mut state = state.0.lock();
if !state.web_input.is_touch {
state.web_input.mouse_pos = Some(pos_from_mouse_event(state.canvas_id(), &event));
state.web_input.mouse_down = true;
invalidate(&mut state).unwrap();
event.stop_propagation();
event.prevent_default();
}
}) as Box<dyn FnMut(_)>);
canvas.add_event_listener_with_callback(event_name, closure.as_ref().unchecked_ref())?;
closure.forget();
}
{
let event_name = "mousemove";
let state = state.clone();
let closure = Closure::wrap(Box::new(move |event: web_sys::MouseEvent| {
let mut state = state.0.lock();
if !state.web_input.is_touch {
state.web_input.mouse_pos = Some(pos_from_mouse_event(state.canvas_id(), &event));
invalidate(&mut state).unwrap();
event.stop_propagation();
event.prevent_default();
}
}) as Box<dyn FnMut(_)>);
canvas.add_event_listener_with_callback(event_name, closure.as_ref().unchecked_ref())?;
closure.forget();
}
{
let event_name = "mouseup";
let state = state.clone();
let closure = Closure::wrap(Box::new(move |event: web_sys::MouseEvent| {
let mut state = state.0.lock();
if !state.web_input.is_touch {
state.web_input.mouse_pos = Some(pos_from_mouse_event(state.canvas_id(), &event));
state.web_input.mouse_down = false;
invalidate(&mut state).unwrap();
event.stop_propagation();
event.prevent_default();
}
}) as Box<dyn FnMut(_)>);
canvas.add_event_listener_with_callback(event_name, closure.as_ref().unchecked_ref())?;
closure.forget();
}
{
let event_name = "mouseleave";
let state = state.clone();
let closure = Closure::wrap(Box::new(move |event: web_sys::MouseEvent| {
let mut state = state.0.lock();
if !state.web_input.is_touch {
state.web_input.mouse_pos = None;
invalidate(&mut state).unwrap();
event.stop_propagation();
event.prevent_default();
}
}) as Box<dyn FnMut(_)>);
canvas.add_event_listener_with_callback(event_name, closure.as_ref().unchecked_ref())?;
closure.forget();
}
{
let event_name = "touchstart";
let state = state.clone();
let closure = Closure::wrap(Box::new(move |event: web_sys::TouchEvent| {
let mut state = state.0.lock();
state.web_input.is_touch = true;
state.web_input.mouse_pos = Some(egui_web::pos_from_touch_event(&event));
state.web_input.mouse_down = true;
invalidate(&mut state).unwrap();
event.stop_propagation();
event.prevent_default();
}) as Box<dyn FnMut(_)>);
canvas.add_event_listener_with_callback(event_name, closure.as_ref().unchecked_ref())?;
closure.forget();
}
{
let event_name = "touchmove";
let state = state.clone();
let closure = Closure::wrap(Box::new(move |event: web_sys::TouchEvent| {
let mut state = state.0.lock();
state.web_input.is_touch = true;
state.web_input.mouse_pos = Some(egui_web::pos_from_touch_event(&event));
invalidate(&mut state).unwrap();
event.stop_propagation();
event.prevent_default();
}) as Box<dyn FnMut(_)>);
canvas.add_event_listener_with_callback(event_name, closure.as_ref().unchecked_ref())?;
closure.forget();
}
{
let event_name = "touchend";
let state = state.clone();
let closure = Closure::wrap(Box::new(move |event: web_sys::TouchEvent| {
let mut state = state.0.lock();
state.web_input.is_touch = true;
state.web_input.mouse_down = false; // First release mouse to click...
paint(&mut state).unwrap(); // ...do the clicking...
state.web_input.mouse_pos = None; // ...remove hover effect
invalidate(&mut state).unwrap();
event.stop_propagation();
event.prevent_default();
}) as Box<dyn FnMut(_)>);
canvas.add_event_listener_with_callback(event_name, closure.as_ref().unchecked_ref())?;
closure.forget();
}
{
let event_name = "wheel";
let state = state.clone();
let closure = Closure::wrap(Box::new(move |event: web_sys::WheelEvent| {
let mut state = state.0.lock();
state.web_input.scroll_delta.x -= event.delta_x() as f32;
state.web_input.scroll_delta.y -= event.delta_y() as f32;
invalidate(&mut state).unwrap();
event.stop_propagation();
event.prevent_default();
}) as Box<dyn FnMut(_)>);
canvas.add_event_listener_with_callback(event_name, closure.as_ref().unchecked_ref())?;
closure.forget();
}
Ok(())
}