canvas画一个时钟

时间：2024-01-10 08:14:50

效果图如下

canvas画一个时钟

 <!DOCTYPE html>

 <html lang="en">

 <head>

     <meta charset="UTF-8">

     <title>Document</title>

 </head>

 <body>

     <canvas id="canvas" width="500" height="500"></canvas>

 </body>

 <script>

 var canvas = document.getElementById("canvas");

 var can = canvas.getContext("2d");

 function drawClock(c){

     c.clearRect(0,0,500,500);

     var now = new Date();

     var hours = now.getHours();

     var minutes = now.getMinutes();

     var seconds = now.getSeconds();

     hours = hours>12?hours-12:hours;

     hours = hours+minutes/60;

     var time = now.toLocaleString();

     console.log(hours,minutes,seconds);

     c.beginPath();

     c.lineWidth=8;

     c.arc(250,250,200,0,Math.PI*2,false);

     c.stroke();

     for(var i=0;i<12;i++){

         c.save();

         c.lineWidth=5;

         c.translate(250,250);//将起始位置移动到圆心。

         c.rotate(i*30*Math.PI/180);//旋转，这里是画刻度的关键，画刻度的线条每次循环都在一个地方，但是画布旋转了。
　　　　　　　　　　　　　　　　　　　　　　　　就像切香肠时刀的落点不变，每次将香肠往前推。

         c.beginPath();

         c.moveTo(0,-180);

         c.lineTo(0,-195);

         c.closePath();

         c.stroke();

         c.restore();

     }

     for(var i=0;i<60;i++){

         c.save();

         c.lineWidth= 3;

         c.translate(250,250);

         c.rotate(6*i*Math.PI/180);

         c.beginPath();

         c.moveTo(0,-190);

         c.lineTo(0,-195);

         c.closePath();

         c.stroke();

         c.restore();

     }

     //表盘中心

     c.lineWith=1;

     c.beginPath();

     c.arc(250,250,4,0,360,false);

     c.fill();

     c.closePath();

     //时针

     c.save();

     c.translate(250,250);

     c.rotate(hours*30*Math.PI/180);

     c.lineWidth = 7;

     c.beginPath();

     c.moveTo(0,15);

     c.lineTo(0,-120);

     c.stroke();

     c.closePath();

     c.restore();

     //分针

     c.save();

     c.translate(250,250);

     c.rotate(minutes*6*Math.PI/180);

     c.lineWidth=3;

     c.moveTo(0,15);

     c.lineTo(0,-135);

     c.stroke();

     c.restore();

     //秒针

     c.save();

     c.translate(250,250);

     c.rotate(seconds*6*Math.PI/180);

     c.lineWidth=1;

     c.moveTo(0,15);

     c.lineTo(0,-160);

     c.stroke();

     c.beginPath();

     c.strokeStyle="red";

     c.fillStyle="white";

     c.arc(0,-145,5,0,180,false);

     c.fill();

     c.stroke();

     c.closePath();

     c.beginPath();

     //判断秒数能否被5整除，能整除表示大刻度，反之为小刻度

         if(seconds%5==0){

             c.moveTo(0,-180);

             c.lineTo(0,-195);

             c.lineWidth=5;

         }else{

             c.moveTo(0,-190);

             c.lineTo(0,-195);

             c.lineWidth=3;

         }

         //当秒针走到某个刻度时，相应的边为红色。

         c.strokeStyle="red";

         c.stroke();

         c.closePath();

     c.restore();

     //写时间

     c.font="15px 黑体"

     c.fillText(time,160,150);

 }

 setInterval("drawClock(can)",1000);

 </script>

 </html>

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