js 多张图片加载 环形进度条
css 部分使用 svg 绘制环形
1 svg{width:100px; height: 100px; margin:15% auto 25%; box-sizing:border-box; display: block;} 2 svg circle{fill:none;cx:50;cy:50;} 3 /* svg text{x:40;y:55;} 不起作用 原因不知*/ 4 svg #txt{ x:35;y:55%;fill:red;} 5 svg #backdrop{stroke-linecap:round;stroke:#333; stroke-width:2px;r:48;} 6 svg #progress{stroke:#690; stroke-dasharray:0 1000;stroke-width:3px;r:48;}
此处的 js 放在 body 标签中
1 var mulitImg = [ 2 'http://www.cctv.com/img/2.png', 3 'https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1520235078852&di=a57664a8e118c403bf2d378757e40b08&imgtype=0&src=http%3A%2F%2Fs9.knowsky.com%2Fbizhi%2Fl%2F100001-105083%2F2009530184324945217430590.jpg', 4 'https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1520235078852&di=0a127ba0bf50857c86bd886ef355d2c9&imgtype=0&src=http%3A%2F%2Fpic1.win4000.com%2Fwallpaper%2F4%2F593a3dba085e1.jpg', 5 'https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1520235078851&di=f1dacfe012d7e71c7469a4b0b4df2708&imgtype=0&src=http%3A%2F%2Fpic1.win4000.com%2Fwallpaper%2Fe%2F5902ad376edd5.jpg', 6 'https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1520235078851&di=b6ab0dcfbe939057988cabb0bd0f3899&imgtype=0&src=http%3A%2F%2Fpic1.win4000.com%2Fwallpaper%2F1%2F535a1f52d5f8c.jpg', 7 'https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1520235078850&di=4f0693db95d8e117035f77d7a1d5e493&imgtype=0&src=http%3A%2F%2Fpic1.win4000.com%2Fwallpaper%2Ff%2F594336ec75b26.jpg' 8 9 ]; 10 // 调用函数， 传入图片数组 11 load_img(mulitImg); 12 function load_img(mulitImg) 13 { 14 var svg=document.createElementNS('http://www.w3.org/2000/svg','svg'); 15 document.body.appendChild(svg); 16 var svg_html='<circle id="backdrop" /><text x="35" y="55%" fill="red" id="txt">0%</text><circle id="progress" />'; 17 svg.innerHTML=svg_html; 18 19 var idtxt=document.getElementById('txt'); 20 var progrees=document.getElementById('progress'); 21 var pro_v=parseInt(css(progrees,'stroke-dashoffset')); 22 var r=parseInt(css(progrees,'r')); // 半径 23 var arcLength=Math.floor(2*Math.PI*r); // 周长 24 25 var taget=100; 26 var img = [], 27 flag = 0; 28 29 var imgTotal = mulitImg.length; 30 //添加过渡效果 31 progrees.style.transitionDuration=arcLength/imgTotal/100+'s'; 32 idtxt.style.transitionDelay=arcLength/imgTotal/100/2+'s'; 33 34 for(var i = 0 ; i < imgTotal ; i++){ 35 img[i] = new Image(); 36 img[i].index=i; 37 img[i].src = mulitImg[i] 38 // 图片加载完成 39 img[i].onload = function(){ 40 41 //第i张图片加载完成 42 flag++; 43 idtxt.textContent=(flag/imgTotal).toFixed(2) *100+'%'; 44 progrees.style.strokeDasharray=arcLength*(flag/imgTotal)+' 1000';// 第二个值必须大于周长 45 46 if( flag == imgTotal ){ 47 //全部加载完成 48 } 49 }; 50 // 图片加载失败----继续执行，可以选择用另一张图片替换 51 img[i].onerror = function(){ 52 //第i张图片加载失败 53 54 flag++; // 继续执行 55 // console.log(this.index+':'+this.src) 56 idtxt.textContent=(flag/imgTotal).toFixed(2) *100+'%'; 57 progrees.style.strokeDasharray=arcLength*(flag/imgTotal)+' 1000';// 第二个值必须大于周长 58 if( flag == imgTotal ){ 59 //全部加载完成 60 } 61 }; 62 } 63 64 // 获取css 样式 65 function css(t, n) { 66 return t.currentStyle ? t.currentStyle[n] : getComputedStyle(t, !1)[n] 67 } 68 }
