js Canvas绘制圆形时钟教程

本文实例为大家分享了Canvas绘制圆形时钟的具体代码，供大家参考，具体内容如下

<!DOCTYPE html>
<html>
<head lang="en">
  <meta charset="UTF-8">
  <title>canvas-clock</title>
</head>
<body>
  <canvas id="canvas" width="500px" height="500px">
    你的浏览器不支持该元素！赶紧下载最新版本浏览器或使用其他浏览器！
  </canvas>
  <script>
    //获取到canvas元素
    var canvas = document.getElementById('canvas');
    //获取canvas中的画图环境
    var context = canvas.getContext('2d'); 

    //时钟的大小
    function drowClock(){
      //钟表的大小：初始值设置
      var clockDimensions = 150; 

      //清理当前画布，以便后期绘制
      context.clearRect(0,0,canvas.width,canvas.height);
      //绘制表盘
      context.beginPath(); //开启新路径
      context.lineWidth = clockDimensions/15;
      context.strokeStyle = "#A7C0DC";
      //绘制表盘圆圈
      context.arc(canvas.width/2,canvas.height/2,clockDimensions,0,Math.PI*2,false);
      context.stroke();//描边绘制 

      //绘制表盘的刻度线
      for(var i=1;i<=60;i++){
        if(i%5==0){
          context.save();//保存当前绘制环境
          context.beginPath();
          context.lineWidth =clockDimensions/30;
          context.strokeStyle = "#9AABB1";
          //重置坐标原点（0,0）
          context.translate(canvas.width/2,canvas.height/2);
          //绘制环境旋转方法,以（0,0）为参考点进行旋转
          context.rotate(Math.PI*2/60 * i);
          context.moveTo(0,clockDimensions-clockDimensions/30);
          context.lineTo(0,clockDimensions-clockDimensions/8);
          context.stroke();
          context.beginPath();
          context.textAlign = 'center';
          context.textBaseline = 'middle';
          context.font = 'bold '+Math.floor(clockDimensions/10)+'px 宋体';
          context.fillStyle = "#03671F";
          context.fillText(i/5,0,0-(clockDimensions-clockDimensions/5));
          context.fill();
          context.restore();//恢复当前保存的绘制环境
        }else {
          context.save();
          context.beginPath();
          context.lineWidth = Math.floor(clockDimensions/100);
          context.strokeStyle = "#8EA5AB";
          //重置坐标原点（0,0）
          context.translate(canvas.width / 2, canvas.height / 2);
          //绘制环境旋转方法,以（0,0）为参考点进行旋转
          context.rotate(Math.PI * 2 / 60 * i);
          context.moveTo(0, clockDimensions-clockDimensions/20);
          context.lineTo(0, clockDimensions-clockDimensions/10);
          context.stroke();
          context.restore();
        }
      } 

      //获取当前windows的时间
      var now = new Date();
      var sec = now.getSeconds();
      var min = now.getMinutes();
      var hour = now.getHours(); 

      //获取精准的小时数
      hour = hour +min/60 + sec/3600;
      //转换为12进制
      hour = hour>12?(hour-12):hour;
      //获取精准的分钟数
      min = min + sec/60; 

      //绘制时针
      context.save();
      context.beginPath();
      context.lineWidth = clockDimensions/30;
      context.strokeStyle = "#596C74";
      //重置坐标原点（0,0）
      context.translate(canvas.width / 2, canvas.height / 2);
      //绘制环境旋转方法,以（0,0）为参考点进行旋转
      context.rotate(Math.PI * 2 / 12 * hour);
      context.moveTo(0, clockDimensions/10);
      context.lineTo(0, 0-clockDimensions/2);
      context.stroke();
      context.restore(); 

      //绘制分针
      context.save();
      context.beginPath();
      context.lineWidth = clockDimensions/40;
      context.strokeStyle = "#596C74";
      //重置坐标原点（0,0）
      context.translate(canvas.width / 2, canvas.height / 2);
      //绘制环境旋转方法,以（0,0）为参考点进行旋转
      context.rotate(Math.PI * 2 / 60 * min);
      context.moveTo(0, clockDimensions/8);
      context.lineTo(0, 0-(clockDimensions-clockDimensions/5));
      context.stroke();
      context.restore(); 

      //绘制秒针
      context.save();
      //重置坐标原点（0,0）
      context.translate(canvas.width / 2, canvas.height / 2);
      context.beginPath();
      context.lineWidth = clockDimensions/50;
      context.strokeStyle = "#738B93";
      //绘制环境旋转方法,以（0,0）为参考点进行旋转
      context.rotate(Math.PI * 2 / 60 * sec);
      context.moveTo(0, clockDimensions/6);
      context.lineTo(0, 0-(clockDimensions-clockDimensions/10));
      context.stroke();
      //修饰秒针
      context.beginPath();
      context.arc(0,0-(clockDimensions-clockDimensions/3),clockDimensions/20,0,Math.PI*2,true);
      context.fillStyle = "#2FFC14";
      context.fill();
      context.lineWidth = clockDimensions/50;
      context.stroke();
      //修饰圆心
      context.beginPath();
      context.fillStyle = "#738B93";
      context.arc(0,0,clockDimensions/20,0,Math.PI*2,true);
      context.fill();
      context.restore();
    }
    drowClock();
    setInterval(drowClock,1000); 

  </script>
</body>
</html> 

效果图：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。