There are several methods that can be used to extend the
toolkit; not all of them are recommended or supported. The best way
to create most extensions is with a plug-in; extended documentation
for creating plug-ins is provided in the next section.
- Creating a plug-in can be very simple to very complex, and is generally the best method for
changing or extending the toolkit. Plug-ins can be used to accomplish almost any
modification that is needed for toolkit processing, from minor style tweaks to extensive,
complicated new output formats.
- The PDF process was initially developed independently of the toolkit,
and created its own extension mechanism using customization directories.
Many (but not quite all) of the capabilities available through PDF
customization directories are now available through plug-ins.
- Using a single XSL file as an override by passing it in as a parameter.
For example, when building XHTML content, the XSL parameter allows
users to specify a single local XSL file (inside or outside of the
toolkit) that is called in place of the default XHTML code. Typically,
this code imports the default processing code, and overrides a couple
of processing routines. This approach is best when the override is
very minimal, or when the style varies from build to build. However,
any extension made with this sort of override is also possible with
a plug-in.
- Editing DITA-OT code directly may work in some cases, but is not
advised. Modifying the code directly significantly increases the work
and risk involved with future upgrades. It is also likely that such
modifications will break plug-ins provided by others, limiting the
function available to the toolkit.