将div的内容生成清晰的PDF、高清PDF

<button type="button" class="btn btn-primary " id="pdfDown" >PDf导出</button>

$("#pdfDown").on('click',function(){
var element = $(".orgchart"); // 这个dom元素是要导出pdf的div容器，即要生成PDF的div
var w; // 获得该容器的宽
var h; // 获得该容器的高
//因为我是两种分布情况，故而有了下边的if、else，如果只有一种用else里的即可
if($(".btnActive").attr('id') == 'Hmerage'){
h = element.outerWidth()
w = element.outerHeight()
}else{
w = element.outerWidth()
h = element.outerHeight()
}
var offsetTop = element.offset().top; // 获得该容器到文档顶部的距离
var offsetLeft = element.offset().left; // 获得该容器到文档最左的距离
var canvas = document.createElement("canvas");
canvas.width = w * 2; // 将画布宽&&高放大两倍
canvas.height = h * 2;
var context = canvas.getContext("2d");
var scale = 2;
context.scale(2, 2);
context.translate(-offsetLeft, -offsetTop); var opts = {
scale: scale,
canvas: canvas,
width: w,
height: h,
useCORS: true,
background: '#ffffff'
} html2canvas(element, opts).then(function (canvas) { var contentWidth = canvas.width;
var contentHeight = canvas.height;
//一页pdf显示html页面生成的canvas高度;
var pageHeight = contentWidth / 592.28 * 841.89;
//未生成pdf的html页面高度
var leftHeight = contentHeight;
//页面偏移
var position = 0;
//a4纸的尺寸[595.28,841.89]，html页面生成的canvas在pdf中图片的宽高
var imgWidth = 595.28*1.01;
var imgHeight = 592.28 / contentWidth * contentHeight*1.01; var pageData = canvas.toDataURL('image/jpeg', 1.0);
var pdf = new jsPDF('', 'pt', 'a4'); //有两个高度需要区分，一个是html页面的实际高度，和生成pdf的页面高度(841.89)
//当内容未超过pdf一页显示的范围，无需分页
if (leftHeight < pageHeight) {
pdf.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight);
} else { // 分页
while (leftHeight > 0) {
pdf.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight)
leftHeight -= pageHeight;
position -= 841.89;
//避免添加空白页
if (leftHeight > 0) {
pdf.addPage();
}
}
}
pdf.save('content.pdf');
})
})