canvas时钟纯手写

html代码：

<!DOCTYPE html>
<html>
<head>
	<title></title>
	<meta charset="utf-8">
	<style type="text/css">
		div{
			text-align: center;
			margin-top: 250px;
		}
		#clock{
			border:1px solid #ccc;
		}
	</style>
</head>
<body>
	<div>
		<canvas id="clock" width="300px" height="300px"></canvas>
	</div>

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

js代码：

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 rem = width/200;

function drawBackground(){
	ctx.save();
	ctx.translate(r,r);
	ctx.beginPath();
	ctx.lineWidth=10*rem;
	ctx.arc(0,0,r-ctx.lineWidth/2,0,2*Math.PI,false);
	ctx.stroke();
	var hoursNumbers=[3,4,5,6,7,8,9,10,11,12,1,2];
	ctx.font=18*rem+'px Arial';
	ctx.textAlign="center";
	ctx.textBaseline='middle';
	hoursNumbers.forEach(function(number,i){
		var rad = 2*Math.PI/12*i;
		var x = Math.cos(rad)*(r-30*rem);
		var y = Math.sin(rad)*(r-30*rem);
		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-18*rem);
		var y = Math.sin(rad)*(r-18*rem);
		ctx.beginPath();
		if(i%5===0){
			ctx.fillStyle="#000";
			ctx.arc(x,y,2*rem,0,2*Math.PI,false);
		}else{
			ctx.fillStyle="#ccc";
			ctx.arc(x,y,2*rem,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*rem;
	ctx.lineCap = 'round';
	ctx.moveTo(0,10*rem);
	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*rem;
	ctx.lineCap = 'round';
	ctx.moveTo(0,10*rem);
	ctx.lineTo(0,-r+30*rem);
	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*rem,20*rem);
	ctx.lineTo(2*rem,20*rem);
	ctx.lineTo(1,-r+18*rem);
	ctx.lineTo(-1,-r+18*rem);
	ctx.fill();
	ctx.restore();
}
function drawDot(){
	ctx.beginPath();
	ctx.fillStyle="#fff";
	ctx.arc(0,0,3,0,2*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);

猜你喜欢