$("#downpdf").on("click", function () {
document.body.scrollTop=document.documentElement.scrollTop=0
var id=‘task_report‘;
html2canvas($("#"+id), {
scale:2,
background: "#FFFFFF",//如果指定的div没有设置背景色会默认成黑色,这里是个坑
onrendered:function(canvas) {
//未生成pdf的html页面高度
var leftHeight = canvas.height;
var a4Width = 190
var a4Height = 277 //A4大小，210mm x 297mm，四边各保留10mm的边距，显示区域190x277
//一页pdf显示html页面生成的canvas高度;
var a4HeightRef = Math.floor(canvas.width / a4Width * a4Height);
//pdf页面偏移
var position = 0;
var pageData = canvas.toDataURL(‘image/jpeg‘, 1.0);
var pdf = new jsPDF(‘p‘, ‘mm‘, ‘a4‘); //A4纸，纵向
var index = 1,
canvas1 = document.createElement(‘canvas‘),
height;
pdf.setDisplayMode(‘fullwidth‘, ‘continuous‘, ‘FullScreen‘);
var pdfName=‘TriButte漏洞管理平台扫描报告‘;
function createImpl(canvas) {
console.log(leftHeight,a4HeightRef)
if (leftHeight > 0) {
index++;
var checkCount = 0;
if (leftHeight > a4HeightRef) {
var i = position + a4HeightRef;
for (i = position + a4HeightRef; i >= position; i--) {
var isWrite = true
for (var j = 0; j < canvas.width; j++) {
var c = canvas.getContext(‘2d‘).getImageData(j, i, 1, 1).data
if (c[0] != 0xff || c[1] != 0xff || c[2] != 0xff) {
isWrite = false
break
}
}
if (isWrite) {
checkCount++
if (checkCount >= 10) {
break
}
} else {
checkCount = 0
}
}
height = Math.round(i - position) || Math.min(leftHeight, a4HeightRef);
if(height<=0){
height = a4HeightRef;
}
} else {
height = leftHeight;
}
canvas1.width = canvas.width;
canvas1.height = height;
console.log(index, ‘height:‘, height, ‘pos‘, position);
var ctx = canvas1.getContext(‘2d‘);
ctx.drawImage(canvas, 0, position, canvas.width, height, 0, 0, canvas.width, height);
var pageHeight = Math.round(a4Width / canvas.width * height);
// pdf.setPageSize(null, pageHeight)
if(position != 0){
pdf.addPage();
}
pdf.addImage(canvas1.toDataURL(‘image/jpeg‘, 1.0), ‘JPEG‘, 10, 10, a4Width, a4Width / canvas1.width * height);
leftHeight -= height;
position += height;
if (leftHeight > 0) {
setTimeout(createImpl, 500, canvas);
} else {
pdf.save(pdfName + ‘.pdf‘);
}
}
}
//当内容未超过pdf一页显示的范围，无需分页
if (leftHeight < a4HeightRef) {
pdf.addImage(pageData, ‘JPEG‘, 0, 0, a4Width, a4Width / canvas.width * leftHeight);
pdf.save(pdfName + ‘.pdf‘)
} else {
try {
pdf.deletePage(0);
setTimeout(createImpl, 500, canvas);
} catch (err) {
// console.log(err);
}
}
}
})
});
原文：/ellisonzhang/p/12851068.html
