PDF/UA Support in PDFlib GmbH Products
All products in the PDFlib 9 family support the creation of PDF/UA according to the standard:
- The PDFlib base product can be used to create PDF documents based on text, graphics and images along with the corresponding structure tags. Tagged PDF functionality in PDFlib has already been introduced in 2004.
- The extended product PDFlib+PDI additionally allows the import of pages from PDF/UA documents including the associated part of the structure hierarchy. This makes PDFlib+PDI 9 the first product worldwide which can be used to assemble existing PDF/UA documents to combined output which in turn conforms to the standard (sometimes called »content aggregation«).
- PDFlib Personalization Server (PPS) is the top-level product for template-based PDF creation. It also supports PDF/UA output which means that personalized accessible PDF documents can be created.
PDFlib is not simply a low-level toolkit which makes it possible to somehow create PDF/UA-1. Instead, PDFlib implements all rules and requirements of the PDF/UA standard: it automatically creates accessible constructs where possible, and prevents the user from violating any PDF/UA requirement. The resulting output is guaranteed to conform to all PDF/UA requirements as far as machine-testable criteria are concerned. Criteria which require human judgment are obviously under the user’s responsibility.
PDFlib’s support for PDF/A-1a, PDF/A-2a and PDF/A-3a in combination with PDF/UA-1 makes it easy to create PDF output which is both accessible and archivable.
Creating PDF/UA with PDFlib
PDFlib 9 takes care of PDF/UA-1 requirements automatically as far as possible. Developers working with PDFlib products must provide structure information to the PDFlib programming interface so that PDFlib can create the document’s structure hierarchy. PDFlib applies PDF/UA-1 checks to all user-supplied structure tags and attributes to ensure conforming output. PDFlib automatically tags tables and artifacts which is a big time-saver for the developer and simplifies the creation of a standard-conforming structure hierarchy. Alternative text can be attached to images and vector graphics.
Sample code for a variety of programming languages and development environments is provided with the PDFlib distribution. Additional programming techniques for PDF/UA are available in the PDFlib Cookbook.
Assembling PDF/UA with PDFlib+PDI and PPS
PDFlib+PDI and the PDFlib Personalization Server (PPS) can be used to assemble pages from existing documents and enhance them with new content. PDFlib+PDI 9 introduced the capability to import the corresponding parts of the structure hierarchy with each page and merge it into the generated document’s structure hierarchy. If the imported document conforms to PDF/UA, the resulting output also conforms to the standard. With this functionality accessible compound documents can be assembled from smaller parts.
Digitally signing PDF/UA with PDFlib PLOP DS
PDFlib PLOP DS is our product for applying digital signatures to PDF documents. PLOP DS applies signatures in a PDF/UA-conforming manner: if the input conforms to PDF/UA, the signed output is guaranteed to conform to the PDF/UA standard as well