西兰花伟大炮
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
#canvas{
border: 1px solid #e9e0b5;
margin: 200px auto;
display: block;
}
</style>
</head>
<body>
<canvas id="canvas" width="300" height="300"></canvas>
<script>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var width = ctx.canvas.width;
var height = ctx.canvas.height;
var r = width /2;
function drawbackground(ctx){
ctx.save();
ctx.translate(r,r);
ctx.beginPath();
ctx.lineWidth = 10;
ctx.arc(0 ,0 , r-5, 0, Math.PI * 2);
ctx.stroke();
ctx.closePath();
ctx.textAlign = "center";
ctx.textBaseline = "middle";
ctx.font = "18px Arial";
var hourNumber = [3,4,5,6,7,8,9,10,11,12,1,2];
hourNumber.forEach(function (number,i) {
var rad = Math.PI * 2 / 12 * i;
var x = Math.cos(rad) * (r - 40);
var y = Math.sin(rad) * (r - 40);
ctx.fillText(number,x,y);
});
for(var i = 0;i < 60;i++){
var raddot = Math.PI * 2 / 60 * i;
var x = Math.cos(raddot) * (r - 25);
var y = Math.sin(raddot) * (r - 25);
ctx.beginPath();
if(i % 5 === 0){
ctx.arc(x,y,3,0,Math.PI * 2);
ctx.fillStyle = "#000";
}else
{
ctx.arc(x,y,3,0,Math.PI * 2);
ctx.fillStyle = "gray";
}
ctx.fill();
}
}
function drawhour(hour,minute){
ctx.save();
ctx.beginPath();
var radhour = Math.PI * 2 /12 * hour;
var radminute = Math.PI * 2 /12 / 60 * minute;
ctx.rotate(radhour + radminute);
ctx.lineWidth = 6;
ctx.lineCap = "round";
ctx.moveTo(0,10);
ctx.lineTo(0,-r + 50);
ctx.stroke();
ctx.restore();
}
function drawminute(minute){
ctx.save();
ctx.beginPath();
var radhour = Math.PI * 2 /60 * minute;
ctx.rotate(radhour);
ctx.lineWidth = 3;
ctx.lineCap = "round";
ctx.moveTo(0,15);
ctx.lineTo(0,-r + 40);
ctx.stroke();
ctx.restore();
}
function drawsecond(second){
ctx.save();
ctx.beginPath();
var radsecond = Math.PI * 2 /60 * second;
ctx.rotate(radsecond);
ctx.moveTo(-2,20);
ctx.lineTo(2,20);
ctx.lineTo(-1,-r + 35);
ctx.lineTo(1,-r + 35);
ctx.fillStyle = "red";
ctx.fill();
ctx.restore();
}
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(ctx);
drawhour(hour,minute);
drawminute(minute);
drawsecond(second);
ctx.restore();
}
draw();
setInterval(draw,1000);
</script>
</body>
</html>你又不贴代码，还要看你课程才知道你问的是什么，看你的问题，应该是时间转换错了，对比一下上面的吧