SECTION 4.10
375
Optional Content
Optional Content Properties Dictionary
The optional
OCProperties
entry in the document catalog (see Section 3.6.1,
optional content properties dictionary,
which con-
tains a list of all the optional content groups in the document, as well as informa-
tion about the default and alternate configurations for optional content. This
dictionary is required if the file contains any optional content; if it is missing, a
PDF consumer should ignore any optional content structures in the document.
This dictionary contains the following entries:
TABLE 4.50 Entries in the optional content properties dictionary
KEY
TYPE
VALUE
OCGs
array
(Required)
An array of indirect references to all the optional content groups in
the document (see Section 4.10.1, “Optional Content Groups”), in any order.
Every optional content group must be included in this array.
(Required)
The default viewing optional content configuration dictionary (see
(Optional)
An array of alternate optional content configuration dictionaries (see
plications or features.
D
dictionary
array
Configs
Optional Content Configuration Dictionaries
The
D
and
Configs
entries in Table 4.50 are
configuration dictionaries,
which rep-
resent different presentations of a document’s optional content groups for use by
PDF processing applications or features. The
D
configuration dictionary specifies
the initial state of the optional content groups when a document is first opened.
Configs
lists other configurations that may be used under particular circumstanc-
es. The entries in a configuration dictionary are shown in Table 4.51.