Previous Next

                                          1022
   APPENDIX F                                                           Linearized PDF



   longer linearized and subsequently is treated as ordinary PDF. Linearizing it
   again may require reprocessing the entire file; see Section F.4.6, “Accessing an Up-
   dated File,” for details.

   Linearized PDF requires two additions to the PDF specification:

   • Rules for the ordering of objects in the PDF file
   • Additional data structures, called hint tables, that enable efficient navigation
     within the document

   Both of these additions are relatively simple to describe; however, using them
   effectively requires a deeper understanding of their purpose. Consequently, this
   appendix goes considerably beyond a simple specification of these PDF exten-
   sions to include background, motivation, and strategies.

   • Section F.1, “Background and Assumptions,” provides background information
     about the properties of the Web that are relevant to the design of Linearized
     PDF.
   • Section F.2, “Linearized PDF Document Structure,” specifies the file format and
     object-ordering requirements of Linearized PDF.
   • Section F.3, “Hint Tables,” specifies the detailed representation of the hint
     tables.
   • Section F.4, “Access Strategies,” outlines strategies for accessing Linearized PDF
     over a network, which in turn determine the optimal way to organize the PDF
     file.

   The reader is assumed to be familiar with the basic architecture of the Web, in-
   cluding terms such as URL, HTTP, and MIME.


F.1 Background and Assumptions

   The principal problem addressed by the Linearized PDF design is the access of
   PDF documents through the Web. This environment has the following important
   properties:

   • The access protocol (HTTP) is a transaction consisting of a request and a re-
     sponse. The client presents a request in the form of a URL, and the server sends
     a response consisting of one or more MIME-tagged data blocks.

Previous Next