PDFlib Text Extraction Toolkit (TET) Manual

9 The pCOS Interface
The pCOS (PDFlib Comprehensive Object Syntax) interface provides a simple and elegant
facility for retrieving arbitrary information from all sections of a PDF document which
do not describe page contents, such as page dimensions, metadata, interactive elements,
etc. pCOS users are assumed to have some basic knowledge of internal PDF structures
and dictionary keys, but do not have to deal with PDF syntax and parsing details.
We strongly recommend that pCOS users obtain a copy of the PDF Reference, which is
available as follows:
Adobe Systems Incorporated: PDF Reference, Sixth Edition: Version 1.7. Downloadable
PDF from www.adobe.com/devnet/pdf/pdf_reference.html.
9.1 Simple pCOS Examples
Cookbook A collection of pCOS coding fragments for solving specific problems can be found in the
pCOS Cookbook.
Assuming a valid PDF document handle is available, the pCOS functions TET_pcos_get_
number( ), TET_pcos_get_string( ), and TET_pcos_get_stream( ) can be used to retrieve information
from a PDF using the pCOS path syntax. Table 9.1 lists some common pCOS
paths and their meaning.
Table 9.1 pCOS paths for commonly used PDF objects
pCOS path type explanation
length:pages number number of pages in the document
/Info/Title string document info field Title
/Root/Metadata stream XMP stream with the document’s metadata
fonts[...]/name string name of a font; the number of entries can be retrieved with length:fonts
fonts[...]/vertical boolean check a font for vertical writing mode
fonts[...]/embedded boolean embedding status of a font
pages[...]/width number width of the visible area of the page
Number of pages.
The total number of pages in a document can be queried as follows:
pagecount = tet.pcos_get_number(doc, "length:pages");
Document information fields can be retrieved with the follow-
Document info fields.
ing code sequence:
objtype = tet.pcos_get_string(doc, "type:/Info/Title");
if (objtype.equals("string"))
{
/* Document info key found */
title = tet.pcos_get_string(doc, "/Info/Title");
}
9.1 Simple pCOS Examples 105