canvas-in-websys.rs

// https://rustwasm.github.io/wasm-bindgen/examples/2d-canvas.html
use wasm_bindgen::prelude::*;
use wasm_bindgen::JsCast;

#[wasm_bindgen(start)]
pub fn start() {
    web_sys::console::log_1(&"start".into());
    let document = web_sys::window().unwrap().document().unwrap();

    let canvas = document.create_element("canvas").unwrap();
    canvas.set_attribute("width", "400px").unwrap();
    canvas.set_attribute("height", "320px").unwrap();
    canvas.set_attribute("style", "background: #eee").unwrap();

    let canvas: web_sys::HtmlCanvasElement = canvas
        .dyn_into::<web_sys::HtmlCanvasElement>()
        .map_err(|_| ())
        .unwrap();
    let context = canvas
        .get_context("2d")
        .unwrap()
        .unwrap()
        .dyn_into::<web_sys::CanvasRenderingContext2d>()
        .unwrap();
    document.body().unwrap().append_child(&canvas).unwrap();

    context.begin_path();
    context
        .arc(10.0, 10.0, 5.0, 0.0, std::f64::consts::PI * 2.0)
        .unwrap();

    context.stroke();
}

#[cfg(test)]
mod tests {
    // use super::*;
    #[test]
    fn it_works() {
        assert_eq!(true, true);
    }
}