Creating reusable well-structured PDF as a sequence of component object graphic (COG) elements

Abstract

Portable Document Format (PDF) is a page-oriented, graphically rich format based on PostScript semantics and it is also the format interpreted by the Adobe Acrobat viewers. Although each of the pages in a PDF document is an independent graphic object this property does not necessarily extend to the components (headings, diagrams, paragraphs etc.) within a page. This, in turn, makes the manipulation and extraction of graphic objects on a PDF page into a very difficult and uncertain process.The work described here investigates the advantages of a model wherein PDF pages are created from assemblies of COGs (Component Object Graphics) each with a clearly defined graphic state. The relative positioning of COGs on a PDF page is determined by appropriate 'spacer' objects and a traversal of the tree of COGs and spacers determines the rendering order. The enhanced revisability of PDF documents within the COG model is discussed, together with the application of the model in those contexts which require easy revisability coupled with the ability to maintain and amend PDF document structure.

Reflowable documents composed from pre-rendered atomic components

“…Our sample implementation is built around our existing work in PDF and Component-Object Graphics (COGs) [1], but there is no reason why it could not be implemented in any other format capable of tightly specifying page imaging operations. It builds on existing software, principally pdfdit, in conjunction with COG Manipulator, as these tools are already capable of producing modular documents with tightly specified rendering.…”

Document engineering approaches toward scalable and structured multimedia, web and printable documents

“…Document Engineering research relative to document representations to scanned images includes algorithms for image thresholding [33], and relative to PDF includes approaches for the creation of reusable well-structured PDF documents [1]. Arguing that the most important document representation is the Extensible Markup Language (XML), Munson remarks its widespread use on the Web, in business as well as in non-document applications [22].…”

Are PDF Documents Accessible?

“…n PDF PDF is the descendent of Postscript and is oriented toward presentation. Though recent research has experimented with new, more versatile image models (Bagley, Brailsford, and Hardy 2003), these have not yet been incorporated in the commercial format, which is still basically Postscript. PDF is a format of digital dissemination that has replicated paper documents for many years.…”