SECTION 8.5
663
Actions
the
Rect
entry in the annotation with which the URI action is associated). For ex-
ample, if the mouse coordinates in user space are (x
m
,
y
m
) and the annotation
rectangle extends from (ll
x
,
ll
y
) at the lower-left to (ur
x
,
ur
y
) at the upper-right,
the final coordinates (x
f
,
y
f
) are as follows:
(
x
f
=
x
m
–
ll
x
)
y
f
=
ur
y
–
y
m
If the resulting coordinates (x
f
,
y
f
) are fractional, they should be rounded to the
nearest integer values. They are then appended to the URI to be resolved, separat-
ed by commas and preceded by a question mark, as shown in this example:
http : / / www . adobe . com / intro ?100 , 200
To support URI actions, a PDF document’s catalog (see Section 3.6.1, “Document
URI
entry whose value is a
URI dictionary.
At the time of
publication, only one entry is defined for such a dictionary (see Table 8.57).
TABLE 8.57 Entry in a URI dictionary
KEY
TYPE
VALUE
Base
ASCII
string
(Optional)
The
base URI
to be used in resolving relative URI references. URI actions
within the document may specify URIs in partial form, to be interpreted relative to
this base address. If no base URI is specified, such partial URIs are interpreted rela-
tive to the location of the document itself. The use of this entry is parallel to that of
the body element
<BASE >
, as described in the
HTML 4.01 Specification
(see the Bibli-
The
Base
entry allows the URI of the document to be recorded in situations in
which the document may be accessed out of context. For example, if a document
has been moved to a new location but contains relative links to other documents
that have not been moved, the
Base
entry could be used to refer such links to the
true location of the other documents, rather than that of the moved document.
Sound Actions
A
sound action (PDF 1.2)
plays a sound through the computer’s speakers. Table
discussed in Section 9.2, “Sounds.”