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DocBook: The Definitive Guide

DocBook: The Definitive Guide

By Norman Walsh & Leonard Muellner
1st Edition October 1999
1-56592-580-7, Order Number: 5807
652 pages, $36.95 , Includes CD-ROM



Area -- A region defined for a Callout in a graphic or code example


Content Model

Area ::=


Common attributes








Tag Minimization

The start-tag is required for this element. The end-tag is optional, if your SGML declaration allows minimization.


An Area is an empty element holding information about a region in a graphic, program listing, or screen.

The region is generally decorated with a number, symbol, or other distinctive mark. The mark is usually used as the label for the Callout in a CalloutList, which allows the reader to identify which callouts are associated with which regions. The marks may be generated by the processing application from the Areas, or it may be added by some other process. (This is an interchange issue. See Appendix F.)

For a complete description of callouts, see Callout.

Processing expectations

Suppressed. This element provides data for processing but it is not expected to be rendered directly.

The processing expectations of Callouts are likely to deserve special consideration for interchange. See Appendix F.

The Coords, which are required, identify the location of the region. The coordinates are CDATA; how they are interpreted depends on the Units specified:


The coordinates are expressed using the semantics of the CALS graphic attributes. The format of the coordinates is "x1,y1 x2,y2". This identifies a rectangle with the lower-left corner at (x1,y1) and the upper-right corner at (x2,y2). The X and Y coordinates are integers in the range 0 to 10000; they express a percentage of the total distance from 0.00 to 100.00%.


The coordinates are expressed using lines and columns. The format of the coordinates is "line column." In a graphic context, the meaning of this unit is unspecified.


The coordinates are expressed using lines. The format of the coordinates is "startingline endingline." In a graphic context, the meaning of this unit is unspecified.


The coordinates are expressed as a continuous flow of characters. The format of the coordinates is "line1 col1 line2 col2". This identifies a flow of characters that begins at col1 of line1 and extends to col2 of line2. If line1 and line2 are different, then the region includes all of the intervening lines (including text that occurs before col1 and after col2). In other words, this unit does not specify a rectangle. In a graphic context, the meaning of this unit is unspecified.


If specified, then the OtherUnits attribute is expected to identify the units in some implementation-specific way.

The Units attribute is not required, if it is not specified, the semantics of the coordinates must be inherited from the surrounding AreaSpec or AreaSet element or implied in some implementation-specific manner.

In processing systems in which the mark is inserted automatically, the Label attribute is provided as a mechanism for specifying what the mark should be.

The author may point to any relevant information with Linkends. DocBook does not specify a semantic for these links. One possible use would be for providing a link back to the appropriate Callout in an online environment.


These elements contain Area: AreaSet, AreaSpec.


In some contexts, the following elements are allowed anywhere: BeginPage, IndexTerm.



Coords provides the coordinates of the Area. The coordinates should be interpreted using the Units (or OtherUnits) specified.


Label specifies an identifying number or string that may be used in presentation. The Area label might be drawn on top of the figure, for example, at the position indicated by Coords.


Linkends points to the Callout(s) which refer to this Area. (This provides bidirectional linking, which may be useful in online presentation.)


If none of the Units are applicable, set Units to Other and set OtherUnits to some application-specific description of the desired units.


Units indicate how the specified Coords are to be interpreted. The default units vary according to the type of callout specified; CALSPair for graphics and LineColumn for line-oriented elements.


For examples, see GraphicCO, MediaObjectCO, ProgramListingCO.

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