SECTION 4.10
369
Optional Content
teractive use by document consumers. More intents may be added in future PDF
versions; for compatibility with future versions, PDF consumers should allow un-
recognized
Intent
values.
Configuration dictionaries (see “Optional Content Configuration Dictionaries”
Intent
entry. If one or more of a group’s intents is
contained in the current configuration’s set of intents, the group is used in deter-
mining visibility. If there is no match, the group has no effect on visibility.
Note:
If the configuration’s
Intent
is an empty array, no groups are used in determin-
ing visibility; therefore, all content is considered visible.
4.10.2 Making Graphical Content Optional
Graphical content in a PDF file can be made optional by specifying membership
in an optional content group or optional content membership dictionary. Two
primary mechanisms are available:
•
Sections of content streams delimited by marked-content operators can be
made optional, as described in “Optional Content in Content Streams,” below.
•
Form and image XObjects and annotations can be made optional in their en-
tirety by means of a dictionary entry, as described in “Optional Content in
When a piece of optional content in a PDF file is determined to be hidden, the
following occurs:
•
The content is not drawn.
•
Graphics state operations, such as setting the color, transformation matrix, and
clipping, are still applied. In addition, graphics state side effects that arise from
drawing operators are applied; in particular, the current text position is updat-
ed even for text wrapped in optional content. In other words, graphics state pa-
rameters that persist past the end of a marked-content section must be the
same whether the optional content is visible or not. For example, hiding a sec-
tion of optional content does not change the color of objects that do not belong
to the same optional content group.
Note:
This rule also applies to operators that set state that is not strictly graphics
state; for example,
BX
and
EX
.