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我這圓不會出來呀，我'照著打的代碼呀
cutecat1234567890_
2017-03-08
4 回答
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我這圓不會出來呀，我'照著打的代碼呀
2017-03-08
舉報
2017-08-25
PI.不是pi
2017-03-09
18×rem是什么意思啊
2017-03-08
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width,initial-scale=1">
<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="400px" width="400px"></canvas>
</div>
<script type="text/javascript">
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(){
//時鐘的圓
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();
//數(shù)字
var hourNumbers = [3,4,5,6,7,8,9,10,11,12,1,2];
ctx.font = 18 * rem + '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 * rem);
var y = Math.sin(rad) * (r - 30 * rem);
ctx.fillText(number,x,y);
});
//60個小點點
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();
}
}
//時鐘
function drawHour(hour,minute){
ctx.save();
ctx.beginPath();
var rad = 2 * Math.PI / 12 * hour;
var marad = 2 * Math.PI / 12 / 60 * minute;
ctx.rotate(rad + marad);
ctx.lineWidth = 6 * rem;
ctx.lineCap = 'round';
ctx.moveTo(0,10 * rem);
ctx.lineTo(0,-r / 2);
ctx.stroke();
ctx.restore();
}
//分鐘
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();
}
//秒針
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();
}
//中間的圓點
function drawDot(){
ctx.beginPath();
ctx.fillStyle ='#fff';
ctx.arc(0,0,3 * rem,0,2*Math.PI,false);
ctx.fill();
}
//動態(tài)
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);
</script>
</body>
</html>
2017-03-08
function drawBackground(){
//時鐘的圓
ctx.translate(r,r);
ctx.beginPath();
ctx.lineWidth = 10;
ctx.arc(0,0,r -5,0,2*Math.PI,false);
ctx.stroke();
}