我想能讓一個點按照圓周運動，可是寫了沒有反應，想了很久不知道問題在哪。代碼如下<!DOCTYPE html><html><head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1"> <title>Title</title> <style> body{ max-width:600px; height: 500px; margin:0 auto; text-align: center;}.canvas{ width: 200px; height:200px; border:solid cornflowerblue;} </style></head><body><canvas class="canvas" id="canvas1" ></canvas></body><script type="text/javascript">var canvas=document.getElementById("canvas1");var ctx=canvas.getContext("2d");ctx.translate(100,100);ctx.fillStyle="red";var radius=10;var vX=-10;function draw_cirlcle(ctx,vX,radius) { if(vX>10){ vX=-10; } var vY=parseInt(Math.sqrt(radius*radius-vX*vX)); ctx.clearRect(0,0,200,200); ctx.fillRect(vX,vY,2,2); vX++;}setInterval(draw_cirlcle.call(window,ctx,vX,radius),40);</script></html>
我想用canvas畫圓周運動的點動畫，但是js代碼沒有反映，請問問題在哪？
慕尼黑的夜晚無繁華
2018-08-06 11:10:07