PDFlib 8 Windows COM/.NET Tutorial

11.8 PDFlib Block Specification
The Block syntax fully conforms to the PDF Reference which specifies an extension
mechanism that allows applications to store private data attached to the data structures
comprising a PDF page. A detailed description of the PDFlib Block syntax is provided
here for the benefit of users who wish to create Blocks by other means than the Block
Plugin. Plugin users can safely skip this section.
11.8.1 PDF Object Structure for PDFlib Blocks
The page dictionary contains a PieceInfo entry, which has another dictionary as value.
This dictionary contains the key PDFlib with an application data dictionary as value. The
application data dictionary contains two standard keys listed in Table 11.14.
Table 11.14 Entries in a PDFlib application data dictionary
key
LastModified
value
(Data string; required) The date and time when the Blocks on the page were created or most recently
modified.
Private (Dictionary; required) A Block list (see Table 11.15)
A Block list is a dictionary containing general information about Block processing, plus
a list of all Blocks on the page. Table 11.15 lists the keys in a Block list dictionary.
Table 11.15 Entries in a Block list dictionary
key
Version
Blocks
PluginVersion
pdfmark
value
(Number; required) The version number of the Block specification to which the file complies. This document
describes version 9 of the Block specification.
(Dictionary; required) Each key is a name object containing the name of a Block; the corresponding value
is the Block dictionary for this Block (see Table 11.17). The value of the Name key in the Block dictionary
must be identical to the Block’s name in this dictionary.
(String; required unless the pdfmark key is present 1 ) A string containing a version identification of the
Block Plugin which has been used to create the Blocks.
(Boolean; required unless the PluginVersion key is present 1 ) Must be true if the Block list has been generated
by use of pdfmarks.
1. Exactly one of the PluginVersion and pdfmark keys must be present.
314 Chapter 11: PPS and the PDFlib Block Plugin (Edition for COM, .NET, and REALbasic)