尽梨了,谁能告诉我剩下的那 0.2 差在哪?

https://i.v2ex.co/9wcBH2X1l.png

```
function sleep(time = 100) {
　 return new Promise((reslove) => {
　　 setTimeout(() => {
　　　 reslove();
　　}, time)
　})
}

async function drawCircleByMouse(canvasEl, centerX, centerY, radius = 200) {
　 let radian = 0;
　 const pointers = [];

　 while (radian < Math.PI * 2) {
　　 const x = centerX + Math.cos(radian) * radius
　　 const y = centerY + Math.sin(radian) * radius
　　 pointers.push({ x, y });
　　 radian += 0.1;
　}

　 const startPoint = pointers[0];
　 const mousedownEnt = new MouseEvent("mousedown", { clientX: startPoint.x, clientY: startPoint.y, bubbles: true });
　 canvasEl.dispatchEvent(mousedownEnt);

　 for (let point of pointers) {
　　 await sleep();
　　 const mousemoveEnt = new MouseEvent("mousemove", { clientX: point.x, clientY: point.y, bubbles: true });
　　 canvasEl.dispatchEvent(mousemoveEnt);
　　 radian += 0.01;
　}

　 const mousemoveEnt = new MouseEvent("mousemove", { clientX: startPoint.x, clientY: startPoint.y, bubbles: true });
　 canvasEl.dispatchEvent(mousemoveEnt);

　 const endPoint = pointers[pointers.length - 1];
　 const mouseupEnt = new MouseEvent("mouseup", { clientX: endPoint.x, clientY: endPoint.y, bubbles: true });
　 canvasEl.dispatchEvent(mouseupEnt);
}

document.querySelector('a').click();
setTimeout(async () => {
　 const el = document.querySelector('div');
　 const rect = el.getBoundingClientRect();
　 const rem = window.innerHeight / 100 * 9;
　 const centerX = window.innerWidth / 2;
　 const centerY = window.innerHeight / 2 - 20;
　 await drawCircleByMouse(el, centerX, centerY);
}, 2000);
```