random_convex.rs

use gloo_events::EventListener;
use once_cell::sync::Lazy;
use std::sync::atomic::{Ordering, AtomicUsize};
use std::sync::{Mutex, Once};
use wasm_bindgen::JsCast;

use rgeometry::algorithms::convex_hull;

fn ui_range(min: usize, max: usize) {
    let corners = N_CORNERS.load(Ordering::Relaxed);
    let document = web_sys::window().unwrap().document().unwrap();
    let overlay = document.get_element_by_id("ui-overlay").unwrap();
    let val = document
        .create_element("input")
        .unwrap()
        .dyn_into::<web_sys::HtmlInputElement>()
        .unwrap();
    val.set_attribute("type", "range").unwrap();
    val.set_attribute("value", &corners.to_string()).unwrap();
    val.set_attribute("min", &min.to_string()).unwrap();
    val.set_attribute("max", &max.to_string()).unwrap();
    overlay.append_child(&val).unwrap();

    let ev = EventListener::new(&val, "input", move |event| {
        let target = event.target().unwrap();
        let target = target.dyn_into::<web_sys::HtmlInputElement>().unwrap();
        let n = target.value().parse::<usize>().unwrap_or(3);
        N_CORNERS.store(n, Ordering::Relaxed);
        {
            let mut p = POLYGON.lock().unwrap();
            *p = gen_convex();
        }
        clear_screen();
        main();
    });
    ev.forget();
}

static N_CORNERS: AtomicUsize = AtomicUsize::new(5);

static POLYGON: Lazy<Mutex<PolygonConvex<Num>>> = Lazy::new(|| Mutex::new(gen_convex()));

fn gen_convex() -> PolygonConvex<Num> {
    let n = N_CORNERS.load(Ordering::Relaxed);
    PolygonConvex::<i32>::random(n, &mut rand::thread_rng())
        .float()
        .normalize()
}

pub fn main() {
    static START: Once = Once::new();

    START.call_once(|| {
        ui_range(3, 20);
        on_canvas_click(|| {
            {
                let mut p = POLYGON.lock().unwrap();
                *p = gen_convex();
            }
            clear_screen();
            main();
        });
    });

    let p = POLYGON.lock().unwrap();
    render_polygon(&p);
    set_fill_style("grey");
    fill();

    for pt in p.iter_boundary() {
        render_fixed_point(pt.point());
    }
}