js Canvas绘制圆形时钟效果

更新时间：2020-04-24 03:25:01 作者：startmvc

本文实例为大家分享了jsCanvas圆形时钟的具体实现代码，供大家参考，具体内容如下<!DOCTY

本文实例为大家分享了js Canvas圆形时钟的具体实现代码，供大家参考，具体内容如下


<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8" />
 <title>Canvas Clock</title>
 <style type="text/css">

 div{
 text-align: center;
 margin-top: 250px;
 }
 #clock{

 border: 1px solid #ccc;
 }
 </style>
 </head>
 <body>
 <div>
 <canvas id="clock" height="200px" width="200px"></canvas>
 </div>

 <script type="text/javascript" src="js/clock.js"></script>
 </body>
</html>


var dom=document.getElementById('clock');
var cxt=dom.getContext("2d");
var width=cxt.canvas.width;
var height=cxt.canvas.height;
var r=width/2;

function drawBackground(){
 cxt.save();
 cxt.translate(r,r);
 cxt.beginPath();
 cxt.lineWidth=10;
 cxt.arc(0,0,r-5,0,2*Math.PI,false);
 cxt.stroke();
 cxt.font="18px Arial";
 cxt.textAlign='center'
 cxt.textBaseline='middle'
 var hourNums=[3,4,5,6,7,8,9,10,11,12,1,2];
 hourNums.forEach(function(number,i){

 var rad=2*Math.PI/12*i;
 var x=Math.cos(rad)*(r-30);
 var y=Math.sin(rad)*(r-30);
 cxt.fillText(number,x,y);

 });

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

 var rad=2*Math.PI/60*i;
 var x=Math.cos(rad)*(r-18);
 var y=Math.sin(rad)*(r-18);
 cxt.beginPath();
 if(i % 5===0){
 cxt.fillStyle="#000"
 cxt.arc(x,y,2,0,2*Math.PI,false);
 }
 else{
 cxt.fillStyle="#ccc"
 cxt.arc(x,y,2,0,2*Math.PI,false);
 }
 cxt.fill(); 
 }

}

function drawHour(hour,minute){
 cxt.save();
 cxt.beginPath();
 var rad=2*Math.PI/12*hour;
 var mrad=2*Math.PI/12/60*minute
 cxt.rotate(rad+mrad);
 cxt.lineWidth=6;
 cxt.lineCap='round'
 cxt.moveTo(0,10);
 cxt.lineTo(0,-r/2);
 cxt.stroke();
 cxt.restore();
}

function drawMinute(minute){
 cxt.save();
 cxt.beginPath();
 var rad=2*Math.PI/60*minute;
 cxt.rotate(rad);
 cxt.lineWidth=3;
 cxt.lineCap='round'
 cxt.moveTo(0,10);
 cxt.lineTo(0,-r+30);
 cxt.stroke();
 cxt.restore();
}

function drawSecond(second){
 cxt.save();
 cxt.beginPath();
 cxt.fillStyle='#c14543'
 var rad=2*Math.PI/60*second;
 cxt.rotate(rad); 
 cxt.moveTo(-2,20);
 cxt.lineTo(2,20);
 cxt.lineTo(1,-r+18);
 cxt.lineTo(-1,-r+18);
 cxt.fill();
 cxt.restore();
}

function drawDot(){

 cxt.beginPath();
 cxt.fillStyle='#fff'
 cxt.arc(0,0,3,0,2*Math.PI,false);
 cxt.fill();
}

function draw(){

 cxt.clearRect(0,0,width,height);
 var now=new Date();
 var hour=now.getHours();
 var minute=now.getMinutes();
 var second=now.getSeconds();
 drawBackground();
 drawHour(hour,minute);
 drawMinute(minute);
 drawSecond(second);
 drawDot();
 cxt.restore();
}
draw();
setInterval(draw,1000);

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脚本之家。