首页 > 代码库 > canvas仪表盘效果
canvas仪表盘效果
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>canvas仪表盘动画效果</title>
<style type="text/css">
html,
body {
width: 100%;
height: 100%;
margin: 0;
}
canvas {
display: none;
border: 1px solid red;
display: block;
margin: 0 auto;
background: -webkit-linear-gradient(top, #0e83f5 0%, #21bdf6 100%);
}
</style>
<script type="text/javascript">
window.onload = function() {
window.requestAnimFrame = (function() {
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
function(callback) {
window.setTimeout(callback, 1000 / 60);
};
})();
var canvas = document.getElementById(‘canvas‘),
ctx = canvas.getContext(‘2d‘),
cWidth = canvas.width,
cHeight = canvas.height,
score = canvas.attributes[‘data-score‘].value,
radius = 100, //圆的半径
deg0 = Math.PI / 9, //每一格20度
mum = 100, //数字步长
/*
* 要求：圆弧走完，数字得自加完，就得确定圆弧走的次数和数字走的次数相等！
数字最大10000，对应的度数是11*PI/9,那每个步长mum对应的度数如下：
*/
deg1 = mum * Math.PI * 11 / 9 / 10000; // 每mum对应的度数
var angle = 0, //初始角度
credit = 0; //数字默认值开始数
var drawFrame = function() {
if(score < 0 || score > 10000) {
alert(‘额度只能是0--10000‘)
score = 10000;
}
ctx.save();
ctx.clearRect(0, 0, cWidth, cHeight);
ctx.translate(cWidth / 2, cHeight / 2);
ctx.rotate(8 * deg0); //160度
var aim = score * deg1 / mum; //数字对应的弧度数,先确定要走几次,除以mum,然后计算对应的弧度数
if(angle < aim) {
angle += deg1;
}
if(credit < score) {
credit += mum; //默认数字间隔是mum
} else if(credit >= 10000) {
credit = 10000;
}
//信用额度
ctx.save();
ctx.rotate(10 * deg0);
ctx.fillStyle = ‘white‘;
ctx.font = ‘28px Microsoft yahei‘;
ctx.textAlign = ‘center‘;
ctx.fillText(‘信用额度‘, 0, 50);
ctx.restore();
//
text(credit);
ctx.save();
ctx.beginPath();
ctx.lineWidth = 5;
ctx.strokeStyle = ‘rgba(255, 255, 255, 1)‘;
ctx.arc(0, 0, radius, 0, angle, false); //动画圆环
ctx.stroke();
ctx.restore();
ctx.save();
ctx.rotate(10 * deg0); //200度
ctx.restore();
ctx.beginPath();
ctx.strokeStyle = ‘rgba(255, 0, 0, .1)‘;
ctx.lineWidth = 5;
ctx.arc(0, 0, radius, 0, 11 * deg0, false); //设置外圆环220度
ctx.stroke();
ctx.restore();
window.requestAnimFrame(drawFrame);
}
function text(process) {
ctx.save();
ctx.rotate(10 * deg0); //200度
ctx.fillStyle = ‘red‘;
ctx.font = ‘40px Microsoft yahei‘;
ctx.textAlign = ‘center‘;
ctx.textBaseLine = ‘top‘;
ctx.fillText("￥:" + process, 0, 10);
ctx.restore();
}
setTimeout(function() {
document.getElementById("canvas").style.display = "block";
drawFrame();
}, 10)
}
</script>
</head>
<body>
<canvas id="canvas" width="300" height="300" data-score=‘8100‘></canvas>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
#yibiao {
width: 400px;
height: 200px;
background: white;
margin: 0 auto;
position: relative;
overflow: hidden;
}
.yuan1 {
width: 400px;
height: 400px;
position: absolute;
top: 0px;
left: 0px;
border-radius: 50%;
background: black;
opacity: 0.2;
}
.yuan2 {
width: 360px;
height: 360px;
position: absolute;
top: 20px;
left: 20px;
border-radius: 50%;
background: white;
}
.clip {
width: 400px;
height: 400px;
position: absolute;
top: 0px;
left: 0px;
border-radius: 50%;
background: blue;
clip: rect(200px, 400px, 400px, 0px);
transform: rotate(0deg);
}
.num {
position: absolute;
width: 100%;
height: 100px;
top: 100px;
text-align: center;
font-size: 100px;
}
</style>
<script type="text/javascript" src=http://www.mamicode.com/""></script>
<script type="text/javascript">
$(function() {
//默认数字0--10000，默认数字自增步长100
var buchang = 200;
var deg = 180 * buchang / 10000; //每个步长代表的度数
var degs = parseInt($(".num").text()) / buchang * deg; //先计算有几个步长,算出半圆要转的度数
var du = 0; //起始度数
var bu = 0; //数字自增步长
function zhuan() {
$(".clip").css("transform", "rotate(" + du + "deg)");
$(".num").text(bu);
du += deg;
bu += buchang;
if(du >= degs) {
clearInterval(setin);
}
}
var setin = setInterval(zhuan, 30)
})
</script>
</head>
<body>
<div id="yibiao">
<div class="yuan1"></div>
<div class="clip"></div>
<div class="yuan2"></div>
<div class="num">5000</div>
</div>
</body>
</html>
关于requestAnimationFrame
requestAnimationFrame不需要使用者指定循环间隔时间，浏览器会基于当前页面是否可见、CPU的负荷情况等来自行决定最佳的帧速率，从而更合理地使用CPU。
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript">
window.onload = function() {
var id = null;
var i=0;
function a(time) {
console.log(i++);
id = window.requestAnimationFrame(a);
}
function b(){
window.cancelAnimationFrame(id);
}
document.getElementById("start").onclick=a; //相当开始
document.getElementById("zantin").onclick=b; //相当暂停
}
</script>
</head>
<body>
<button id="start">开始</button>
<button id="zantin">暂停</button>
</body>
</html>
点击开始，此时控制台一直计数下去，点击暂停，计数器暂停，再次点击开始会从原来的位置继续计数下去。
canvas仪表盘效果
声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉： 投诉/举报 工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。