3.2.2.3 linkuri

Description. The 'linkuri' APS Attribute defines a URI, to be associated with the object containing this attribute. When the object is selected by a graphical pick operation, then the viewer shall take necessary action to navigate the link. Multiple 'linkuri' attributes may be contained within a single APS.

Parameters. The data record is a SDR of one member, containing three strings (type SF, String Fixed). The first string is the link destination, a URI, the second string (possibly null) is a LinkTitle attribute, and the third string is (possibly null) the Behavior parameter. Note that a null string is a zero-length string, and is not the same as an omitted parameter.

The destination of a link is specified by a Uniform Resource Identifier, or URI. Any valid URL under the specifications of RFC-2396 is a valid value of this parameter. This specification does not constrain the syntax or semantics of a URI in a 'linkuri' that identifies a resource that is not a CGM file (for example, an HTML or XML document).

The Behavior string defines picture behavior associated with the link. The values and meanings are as defined in 3.1.2.2. In cases that the destination is not CGM media type, the 3rd parameter, Behavior, shall be used if picture behavior is to be specified for the link (there is no other option). The Behavior string may also be used for links to CGM media types, and is the preferred method.

In the case that the URI points to CGM media type, the picture behavior may be encoded within the optional fragment identifier in conjunction with the URI structure, per section 3.1.1, "Addressing Pictures and Objects". This form is deprecated, and may be removed in a future edition of this profile. For specifying picture behavior, particular WebCGM 'linkuri' instances shall use either the Behavior string (preferred), or the picture behavior specification embedded in the fragment, but not both.