callout — A called out description of a marked Area
Required attributes are show in bold.
A “callout” is a visual device for associating annotations with an image, program listing, or similar figure. Each location is identified with a mark, and the annotation is identified with the same mark. This is somewhat analagous to the notion of footnotes in print.
An example will help illustrate the concept. In the following example, the synopsis for the mv command is annotated with two marks. Note the location of the old and new filenames.
Somewhere else in the document, usually close by, a
provides a description for each of the callouts:
The old filename. The mv
command renames the file currently called
The new filename. The mv
command changes the name of the old file to
Callout contains an annotation for an individual
callout or a group of callouts. The
Callout points to the
areas that it annotates with ID references.
The areas are identified by coordinates in an an
AreaSet, or by an explicit
Formatted as a displayed block.
CallOuts usually generate text that points the reader to
the appropriate area on the object being augmented. Often, these are
numbered bullets or other distinct visual icons. The same icons should
be used in both places. In other words, whatever identifies the callouts
on the object should generate the same icons on the respective
In online environments, it may also be possible to establish a linking relationship between the two elements.
The processing expectations of
Callouts are likely
to deserve special consideration for interchange. See Appendix E, Interchanging DocBook Documents. This is especially true if your
interchange partners are producing documentation in a medium
that has restricted visual presentation features, such as aural
media or Braille.
The following elements occur in callout: