關於如何解決canvas的畫圓弧時的鋸齒感以及如何讓canvas的圖更清晰？

let width = canvas.width,height=canvas.height;
if (window.devicePixelRatio) {
   canvas.style.width = width + "px";
   canvas.style.height = height + "px";
   canvas.height = height * window.devicePixelRatio;
   canvas.width = width * window.devicePixelRatio;
   ctx.scale(window.devicePixelRatio, window.devicePixelRatio);
}