JavaScript Canvas绘制圆形时钟效果

时间:2020-05-15 晋级的菜鸟人气:0
本文实例为大家分享了Canvas时钟效果展示的具体代码，供大家参考，具体内容如下
<html lang="en"> 
<head> 
 <meta charset="UTF-8"> 
 <title></title> 
 <style> 
  canvas{ 
   display: block; 
   margin: 0 auto; 
   background-color: #fdffad; 
   border: 1px solid #000; 
  } 
 </style> 
 <script type="text/javascript"> 
 
  document.addEventListener('DOMContentLoaded',function(){ 
   var oC=document.querySelector('canvas'); 
   var gd=oC.getContext('2d'); 
   var r=oC.width/2; 
 
   function drawBackground() { 
    gd.save(); 
    //渐变 
 
    var ra = gd.createLinearGradient(600, 0, 400, 0); 
    ra.addColorStop(1, '#2dd9ff'); 
    ra.addColorStop(0, '#8c48dd'); 
 
    //表盘 
    gd.translate(r, r); 
    gd.beginPath(); 
    gd.fillStyle = ra; 
    gd.lineWidth = 10; 
    gd.strokeStyle = '#211f4e'; 
    gd.arc(0, 0, r-5, 0, Math.PI *2, false); 
    gd.fill(); 
    gd.stroke(); 
    //数字 
    for (var i = 1; i < 13; i++) { 
     var rad=i * Math.PI * 2 / 12; 
     var x = Math.sin(rad)*(r-70); 
     var y= -Math.cos(rad)*(r-70); 
     gd.fillStyle = "red"; 
     gd.font = "bold 80px Calibri"; 
     gd.lineWidth = 1; 
     gd.textAlign = 'center'; 
     gd.textBaseline = 'middle'; 
     gd.strokeText(i, x, y); 
    } 
    //点 
    for (var i = 0; i < 60; i++) { 
     gd.beginPath(); 
     var rad=i * Math.PI * 2 / 60; 
     var x = Math.sin(rad)*(r-30); 
     var y= -Math.cos(rad)*(r-30); 
     if (i % 5 == 0) { 
      gd.fillStyle = 'red'; 
     } 
     else { 
      gd.fillStyle = '#ccc' 
     } 
     gd.lineWidth = 2; 
     gd.arc(x, y, 6, 0, Math.PI * 2, false); 
     gd.fill(); 
     gd.stroke(); 
     gd.closePath(); 
    } 
   } 
   //时针 
   function drawHour(h,m){ 
    gd.save(); 
    gd.beginPath(); 
    var rad=2*Math.PI/12*h; 
    var mrad=2*Math.PI/12/60*m; 
    gd.rotate(rad+mrad); 
    gd.lineWidth=20; 
    gd.lineCap='round'; 
    gd.moveTo(0,10); 
    gd.lineTo(0,-r/3); 
    gd.stroke(); 
    gd.closePath(); 
    gd.restore(); 
   } 
   //分针 
   function drawMinutes(m){ 
    gd.save(); 
    gd.beginPath(); 
    var rad=2*Math.PI/60*m; 
    gd.rotate(rad); 
    gd.lineWidth=10; 
    gd.lineCap='round'; 
    gd.moveTo(0,10); 
    gd.lineTo(0,-r/2); 
    gd.stroke(); 
    gd.closePath(); 
    gd.restore(); 
   } 
   //秒针 
   function drawSeconds(s){ 
    gd.save(); 
    gd.beginPath(); 
    var rad=2*Math.PI/60*s; 
    gd.rotate(rad); 
    gd.fillStyle='red'; 
    gd.moveTo(-2,20); 
    gd.lineTo(2,20); 
    gd.lineTo(1,-r+100); 
    gd.lineTo(-1,-r+100); 
    gd.fill(); 
    gd.closePath(); 
    gd.restore(); 
   } 
   //圆点 
   function drawPoint(){ 
    gd.beginPath(); 
    gd.fillStyle='#fff'; 
    gd.arc(0,0,5,Math.PI*2,false); 
    gd.fill(); 
   } 
 
   function drawClock(){ 
    gd.clearRect(0,0,oC.width,oC.height); 
    var oDate=new Date(); 
    var h=oDate.getHours(); 
    var m=oDate.getMinutes(); 
    var s=oDate.getSeconds(); 
    drawBackground(); 
    drawHour(h,m); 
    drawMinutes(m); 
    drawSeconds(s); 
    drawPoint(); 
    gd.restore(); 
 
   } 
   drawClock(); 
   setInterval(drawClock,1000); 
  },false); 
 </script> 
</head> 
<body> 
<canvas width="800" height="800"></canvas> 
</body> 
</html>
效果图：
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