Graphics Programs Reference
In-Depth Information
Key
Value type
Value
/ModDate
date string
The date the document was last modified.
/Creator
text string
The name of the program which originally created this document, if it started as another
format (for example, “Microsoft Word”).
text string
The name of the program which converted this file to PDF, if it started as another format
(for example, the format of a word processor).
/Producer
Example 4-1. Typical document information dictionary
<<
/ModDate (D:20060926213913+02'00')
/CreationDate (D:20060926213913+02'00')
/Title (catalogueproduit-UK.qxd)
/Creator (QuarkXPress: pictwpstops filter 1.0)
/Producer (Acrobat Distiller 6.0 for Macintosh)
/Author (James Smith)
>>
The
date string
format (for
/CreationDate
and
/ModDate
) is discussed in the section
“Dates” on page 45
. The
text string
format (which describes how different encodings
can be used within the string type) is described in
“Text Strings” on page 45
.
Document Catalog
The
document catalog
is the root object of the main object graph, from which all other
objects may be reached through indirect references. In
Table 4-3
, we list the document
catalog dictionary entries which are required, and some of the many optional ones, so
as to introduce brief PDF topics we don't cover elsewhere in these pages.
Table 4-3. The document catalog (*denotes required entry)
Key
Value type
Value
/Type
*
name
Must be
/Catalog
.
/Pages
*
indirect reference to
dictionary
The root node of the page tree. Page trees are discussed in
“Pages and Page Trees” on page 42
.
number tree
A number tree giving the page labels for this document. This
mechanism allows for pages in a document to have more com-
plicated numbering than just 1,2,3…. For example, the preface
of a topic may be numbered i,ii,iii..., whilst the main content
starts again at 1,2,3….These page labels are displayed in PDF
viewers—they have nothing to do with printed output.
/PageLabels
/Names
dictionary
The name dictionary. This contains various
name trees
, which
map names to entities, to prevent having to use object numbers
to reference them directly.
