PDFlib+PDI includes all PDFlib functions, plus the PDF Import Library (PDI). With PDI you can open existing PDF documents and incorporate some pages into the PDFlib output. Use PDFlib+PDI for all PDFlib tasks plus the following:

• impose multiple PDF pages on a single sheet for printing
• add text, such as headers, footers, stamps, or page numbers to existing PDF pages
• place images, e.g. company logo, on existing pages
• add barcodes to existing PDF pages
• assemble existing PDF pages
• add content to PDF/A, PDF/X or PDF/UA documents

The PDI features are integrated in the familiar and easy-to-use PDFlib programming API. Note that the PDF import feature only deals with the actual page contents, and ignores all interactive elements. Also, PDI can not be used to modify existing PDF page contents (but you can add new content using overlays).

PDFlib+PDI also includes the pCOS interface for querying details about a PDF document such as document information fields and XMP metadata, font lists, page size, and many more (see pCOS product description and pCOS Cookbook)