Flattening non-static content (like filled forms) in PDF files for printing

At present, CUPS filter does not support printing the PDF files with dynamic form content. The dynamic form content includes digitally filled forms, tax forms or any kind of registration forms. When the user tries to print the PDF with filled forms, the content either gets vanished or is not displayed properly. CUPS uses a filter named pdftopdf to handle printing of PDF forms. This filter performs some manipulations on PDF file before printing it. These manipulations results into content loss of filled forms. This project aims at adding PDF form flattening support to pdftopdf filter of CUPS wherein, the filter will identify whether the PDF files contains dynamic content or not and if yes, then it will first convert the PDF into static content and then perform its manipulations. It includes adding the actual functionality in QPDF, a library that is internally used by pdftopdf filter for PDF file processing. And then using this functionality of QPDF library to perform the flattening work by the pdftopdf filter.