CHAPTER 8
602
Interactive Features
Note:
Viewer applications should save the state of optional content groups when a
user enters presentation mode and restore it when presentation mode ends. This en-
sures, for example, that transient changes to bullets do not affect the printing of the
document.
A navigation node dictionary (see Table 8.14) specifies actions to execute when
the user makes a navigation request; for example, by pressing an arrow key. The
navigation nodes on a page form a doubly linked list by means of their
Next
and
Prev
entries. The primary node on a page is determined by the optional
PresSteps
entry in a page dictionary (see Table 3.27).
Note:
It is recommended that a viewer application respect navigation nodes only
when in presentation mode (see Section 8.3.3, “Presentations”).
TABLE 8.14 Entries in a navigation node dictionary
KEY
TYPE
VALUE
Type
name
dictionary
dictionary
dictionary
dictionary
number
(Optional)
The type of PDF object that this dictionary describes; must be
NavNode
for a navigation node dictionary.
(Optional)
The sequence of actions to execute when a user navigates forward.
(Optional)
The sequence of actions to execute when a user navigates backward.
(Optional)
The next navigation node, if any.
(Optional)
The previous navigation node, if any.
(Optional)
The maximum number of seconds before the viewer application should
automatically advance forward to the next navigation node. If this entry is not spec-
ified, no automatic advance should occur.
NA
PA
Next
Prev
Dur
A viewer application should support the notion of a
current
navigation node.
When a user navigates to a page, if the page dictionary has a
PresSteps
entry, the
node specified by that entry becomes the current node. (Otherwise, there is no
current node.) If there is a request to navigate forward (such as an arrow key
press) and there is a current navigation node, the following occurs:
1. The sequence of actions specified by
NA
(if present) is executed.
Note:
If
NA
specifies an action that navigates to another page, the actions de-
scribed below for navigating to another page take place, and
Next
should not be
present.