Convert PDF to HTML in PHP similar to DocuSign

we are developing a website that needs to convert PDF files into HTML because some of the PDF has a form (not necessarily fillable PDF, these PDFs are printed to be filled up).

So we want it to be filled up through our website instead of printing the files and filled up by pen. We are going paperless.

DocuSign provides these wherein you can upload PDF, then you can customized it to have textboxes, checkbox. So we're kinda using DocuSign as a reference but still haven't figured out how they did it (Almost perfect convertion of PDF to HTML vice-versa).

So far I've tried several 3rd party softwares for converting PDF to HTML. I've tried XPDF, Poppler, & ImageMagick.

ImageMagick converts a PDF to an image which is not suitable as these images has a large size when converted back to a PDF for printing.

Poppler is a fork XPDF based on my research, I've tried it after using XPDF to see if it's better, it basically does what XPDF do but it converts the PDF to have bigger pixels on the CSS when converted to HTML. That's fine but it loses the font family.

XPDF converts PDF to HTML but the pixel is smaller, so when I convert it back to PDF, it does not fit the whole page, and I still have to manually adjust all the CSS to fit it.

So after using these 3rd party softwares, I convert back the HTML files into PDF using MPDF, and the converted files has so much inconsistencies. Texts are not aligned properly. It's basically not the same as the original PDF.

Any help will be appreciated thanks!

What you are trying to do is not as straight forward it may seem. I have worked with Adobe Sign, formerly known as EchoSign, for years and I have a pretty good idea on how these services work. With that been said I strongly suggest looking into one of these eSign services instead of trying to roll out your own. It will save you a lot of time.

This is how it all works

1. The PDF must have a form itself with named fields. In other words, if you open such PDF in Adobe Reader or Chrome you should be able to fill in the fields. If your PDF does not have a PDF form you will need additional software like Acrobat PRO to create the form.
2. You must convert the PDF into a flat image that can be rendered in the browser.
3. You will need a tool to extract the PDF Form information, such as the field names, types, dimensions, and coordinates.
4. With all this information you can then render the PDF image(s) in the browser. Place absolute positioned HTML form elements over the image using the field type, dimensions, and coordinates from the previous step. Each HTML element needs to reference a PDF form field by name.
5. Once you have collected the information and a data map like field_name => field_value from your HTML widget, you will need to use additional software to programmatically fill in the PDF form in the original PDF. A PDF form information is often stored in FDF or XFDF file.

I don't know of a single tool that will help you with the things outlined above, at least not in PHP. However, I can provide you with a suggestion can be helpful:

• PDFtk Server - Can help you to both, extract the PDF form fields information and fill in the same an XFDF file. Unforutently, the form field information that you can extract with such tool does not include dimensions and coordinates.
• iText - A library available in .Net and Java that can be used to extract detailed information about the PDF form including the dimension and coordinates of the fields. You can create microservice using this toolkit that can communicate with PHP.

There are definitely a lot more tools out there for the job. Hopefully, this information will guide you in the right direction or help you make a decision on how to move forward with your project.