This exanple draws a full circle (2 * pi radian) using the CanvasRenderingContext2d arc function on a HTML canvas. The parameters of the arc function are explained below.
pub fn canvasrenderingcontext2d_arc()
{
let document = web_sys::window().unwrap().document().unwrap();
let canvas = document.get_element_by_id("canvas").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();
context.begin_path();
// x - 75 (x-coordinate of the center of the circle)
// y - 75 (y-coordinate of the center of the circle)
// r - 50 (radius of the circle)
// sAngle - 0 (Starting angle in radians)
// eAngle - f64::consts::PI * 2.0 (Ending angle in radians)
context
.arc(75.0, 75.0, 50.0, 0.0, f64::consts::PI * 2.0)
.unwrap();
context.stroke();
}
pub fn arc(
&self,
x: f64,
y: f64,
radius: f64,
start_angle: f64,
end_angle: f64
) -> Result<(), JsValue>