Html2canvas for each div export to pdf separately

问题

I have Page, It has 6 div with same class name "exportpdf", I am converting those div into pdf using jspdf and html2canvas

var elementTobePrinted = angular.element(attrs.selector),
iframeBody = elementTobePrinted.contents().find('div.exportpdf');

In html2canvas.....

html2canvas(elementTobePrinted, {
  onrendered: function (canvas) {
    var doc = new jsPDF();     
    for(var i=1;i<elementTobePrinted.length;i++){
      doc.addImage(canvas.toDataURL("image/jpeg"), 'jpeg', 15, 40, 180, 160);
      doc.addImage(canvas.toDataURL("image/jpeg"),'JPEG', 0, 0, 215, 40)
      doc.addPage();
    } 

    doc.save(attrs.fileName);
}

I converted page to canvas.its create same div contents for whole pdf. I need each div contents into same pdf with different pages.

Can anyone help me?

The problem is with html2canvas:

doc.addImage(canvas.toDataURL("image/jpeg"), 'jpeg', 15, 40,180, 160);

Here I need to pass elementTobePrinted list to addImage.

回答1:

On angular 2(now 6) framework. u can use the logic as below,

On click execute generateAllPdf() function,
gather all 6 id's from my html collection,
iterate through each id and call html2canvas function,
as html2canvas runs in background to process images, i m using await on function,
after the html2canvas completes its process, i ll save the document,
If suppose i wont use await i ll end-up in downloading an empty page.

below is my code logic,

// As All Functions in js are asynchronus, to use await i am using async here
 async generateAllPdf() {
    const doc = new jsPDF('p', 'mm', 'a4');
    const options = {
      pagesplit: true
    };
    const ids = document.querySelectorAll('[id]');
    const length = ids.length;
    for (let i = 0; i < length; i++) {
      const chart = document.getElementById(ids[i].id);
      // excute this function then exit loop
      await html2canvas(chart, { scale: 1 }).then(function (canvas) { 
        doc.addImage(canvas.toDataURL('image/png'), 'JPEG', 10, 50, 200, 150);
        if (i < (length - 1)) {
          doc.addPage();
        }
      });
    }
    // download the pdf with all charts
    doc.save('All_charts_' + Date.now() + '.pdf');
  }

回答2:

I think the issue here is that elementTobePrintedis not what you think it is.

When you run the code:

var elementTobePrinted = angular.element(attrs.selector)

This will return you a list of every element that matches the conditions, so you said you have 6 of these elements ("It has 6 divs").

Have you tried replacing:

html2canvas(elementTobePrinted, {
  onrendered: function (canvas) {
    var doc = new jsPDF();     
    for(var i=1;i<elementTobePrinted.length;i++) {
      doc.addImage(canvas.toDataURL("image/jpeg"), 'jpeg', 15, 40, 180, 160);
      doc.addImage(canvas.toDataURL("image/jpeg"),'JPEG', 0, 0, 215, 40)
      doc.addPage();
    } 
    doc.save(attrs.fileName);
}

With...

for(var i=0; i<elementTobePrinted.length; i++){
  html2canvas(elementTobePrinted[i], {
    onrendered: function (canvas) {
      var doc = new jsPDF();     
      doc.addImage(canvas.toDataURL("image/jpeg"), 'jpeg', 15, 40, 180, 160);
      doc.addImage(canvas.toDataURL("image/jpeg"),'JPEG', 0, 0, 215, 40)
      doc.addPage();
      doc.save(attrs.fileName);
    }
}

The reason I suggest this is that html2Canvas wants a SINGLE element as its first parameter and your example above passes a list of elements (I think, assuming angular.element(attrs.selector) finds all 6 divs you are trying to print).

来源：https://stackoverflow.com/questions/21784777/html2canvas-for-each-div-export-to-pdf-separately

标签

javascript

html2canvas