如何做时钟
如何制作一个动态的漂亮时钟
3 回答
<!DOCTYPE html>
<html>
<head>
<title>canvas clock</title>
<meta name="viewport" content="width=device-width ,initial-scale=1">
<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="clock.js"></script>
</body>
</html>
//js
var dom = document.getElementById('clock');
var ctx = dom.getContext('2d');
var width = ctx.canvas.width;
var height = ctx.canvas.height;
var r = width/2;
var tem=width/200;
function drawBackground()
{
ctx.save();
ctx.translate(r,r);
ctx.beginPath();
ctx.lineWidth = 10*tem;
ctx.arc(0,0,r-5*tem,0,2*Math.PI,false);
ctx.stroke();
var hourNumbers = [3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1, 2];
ctx.font = 18*tem+'px Arial';
ctx.textAlign='center';
ctx.textBaseline='middle';
hourNumbers.forEach(function(number,i){
var rad = 2 * Math.PI / 12 * i;
var x = Math.cos(rad) * (r-30*tem);
var y = Math.sin(rad) * (r-30*tem);
ctx.fillText(number,x,y); });
for(var i=0;i<60;i++)
{
var rad=2*Math.PI/60*i;
var x = Math.cos(rad) * (r-15*tem);
var y = Math.sin(rad) * (r-15*tem);
ctx.beginPath();
if(i%5==0){
ctx.fillStyle='#000';
ctx.arc(x,y,2*tem,0,2*Math.PI,false);}
else{
ctx.fillStyle='#ccc';
ctx.arc(x,y,2*tem,0,2*Math.PI,false);}
ctx.fill();
}
}
function drawHour(hour,minute)
{
ctx.save();
ctx.beginPath();
var rad=2*Math.PI/12*hour;
var mrad= 2*Math.PI/12/60*minute;
ctx.rotate(rad+mrad);
ctx.lineWidth=6*tem;
ctx.lineCap='round';
ctx.moveTo(0,10*tem);
ctx.lineTo(0,-r/2);
ctx.stroke();
ctx.restore();
}
function drawMinute(minute)
{
ctx.save();
ctx.beginPath();
var rad=2*Math.PI/60*minute;
ctx.rotate(rad);
ctx.lineWidth = 3*tem;
ctx.lineCap = 'round';
ctx.moveTo(0, 10*tem);
ctx.lineTo(0, -r + 30*tem);
ctx.stroke();
ctx.restore();
}
function drawSecond(second)
{
ctx.save();
ctx.beginPath();
ctx.fillStyle='#c14543';
var rad=2*Math.PI/60*second;
ctx.rotate(rad);
ctx.moveTo(-2*tem, 20*tem);
ctx.lineTo(2*tem,20*tem);
ctx.lineTo(1,-r+18*tem);
ctx.lineTo(-1,-r+18*tem);
ctx.fill();
ctx.restore();
}
function drawDot()
{
ctx.beginPath();
ctx.fillStyle="#fff";
ctx.arc(0,0,3*tem,0,2*Math.PI,false);
ctx.fill();
}
function draw()
{
ctx.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();
ctx.restore();
}
draw();
setInterval(draw,1000);
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