By "extension", we mean any data that can be placed in the input XML document that is not addressed by the XSL-FO standard. By having a mechanism for supporting extensions, FOP is able to add features that are not covered in the specification.
The extensions documented here are included with FOP, and are automatically available to you. If you wish to add an extension of your own to FOP, please see the Developers' Extension Page.
Please see the SVG documentation for more details.
By convention, FO extensions in FOP use the "fox" namespace prefix.
To use any of the FO extensions, add a namespace entry for
http://xmlgraphics.apache.org/fop/extensions to the root element:
In previous versions of Apache FOP there was a fox:outline element
which was used to create outlines in PDF files. The redesigned code makes use
of the new bookmark feature defined in the latest XSL 1.1 working draft.
This extension element hasn't been reimplemented for the redesigned code, yet.
This extension element hasn't been reimplemented for the redesigned code, yet.
The two proprietary extension properties, fox:orphan-content-limit and fox:widow-content-limit, are used to improve the layout of list-blocks and tables. If you have a table with many entries, you don't want a single row to be left over on a page. You will want to make sure that at least two or three lines are kept together. The properties take an absolute length which specifies the area at the beginning (fox:widow-content-limit) or at the end (fox:orphan-content-limit) of a table or list-block. The properties are inherited and only have an effect on fo:table and fo:list-block. An example: fox:widow-content-limit="3 * 1.2em" would make sure the you'll have at least three lines (assuming line-height="1.2") together on a table or list-block.