CHAPTER 8
648
Interactive Features
TABLE 8.43 Entries common to all action dictionaries
KEY
TYPE
VALUE
Type
name
name
dictionary or array
(Optional)
The type of PDF object that this dictionary describes; if
present, must be
Action
for an action dictionary.
(Required)
The type of action that this dictionary describes; see Table 8.48
(Optional; PDF 1.2)
The next action or sequence of actions to be per-
formed after the action represented by this dictionary. The value is either
a single action dictionary or an array of action dictionaries to be per-
formed in order; see below for further discussion.
S
Next
The action dictionary’s
Next
entry
(PDF 1.2)
allows sequences of actions to be
chained together. For example, the effect of clicking a link annotation with the
mouse might be to play a sound, jump to a new page, and start up a movie. Note
that the
Next
entry is not restricted to a single action but may contain an array of
actions, each of which in turn may have a
Next
entry of its own. The actions may
thus form a tree instead of a simple linked list. Actions within each
Next
array are
executed in order, each followed in turn by any actions specified in
its
Next
entry,
and so on recursively. Viewer applications should attempt to provide reasonable
behavior in anomalous situations. For example, self-referential actions should not
be executed more than once, and actions that close the document or otherwise
render the next action impossible should terminate the execution sequence.
Applications should also provide some mechanism for the user to interrupt and
manually terminate a sequence of actions.
PDF 1.5 introduces transition actions, which allow the control of drawing during
a sequence of actions; see “Transition Actions” on page 670.
Note:
No action should modify its own action dictionary or any other in the action
tree in which it resides. The effect of such modification on subsequent execution of
actions in the tree is undefined.
8.5.2 Trigger Events
An annotation, page object, or (beginning with PDF 1.3) interactive form field
may include an entry named
AA
that specifies an
additional-actions dictionary
(PDF 1.2)
that extends the set of events that can trigger the execution of an ac-