Adding a new transformation type

Plug-ins can add an entirely new transformation type. The new transformation type can be very simple, such as an HTML build that creates an additional control file; it also can be very complex, adding any number of new processing steps.

About this task

You can use the <transtype> element to define a new transformation type with any new custom parameters that are supported.

When a transformation type is defined, the build expects Ant code to be integrated to define the transformation process. The Ant code must define a target based on the name of the transformation type; if the transformation type is "new-transform", the Ant code must define a target named dita2new-transform.

Procedure

  1. Create an Ant project file for the new transformation. This project file must define a target named "dita2new-transtype," where new-transtype is the name of the new transformation type.
  2. Create a plugin.xml with the following content: 
    <plugin id="plugin-id">
  <transtype name="new-transtype"/>
  <feature extension="dita.transtype.print" value="new-transtype"/>
  <feature extension="ant.import" file="ant-file"/>
</plugin>

    where:

    • plugin-id is the plug-in identifier, for example, com.dita-ot.pdf.
    • new-transtype is the name of the new transformation, for example, dita-ot-pdf.
    • ant-file is the name of the Ant file, for example, build-dita-ot-pdf.xml.

    Exclude the content that is highlighted in bold if the transformation is not intended for print.

  3. Install the plug-in.

Results

You now can use the new transformation.

Examples

Figure 1. Creating a new print transformation

The following plugin.xml file defines a new transformation type named "print-pdf"; it also defines the transformation type to be a print type. The build will look for a dita2print-pdf target.

<?xml version="1.0" encoding="UTF-8"?>
<?xml-model href="https://www.dita-ot.org/rng/plugin.rnc" type="application/relax-ng-compact-syntax"?>

<plugin id="com.example.print-pdf">
  <require plugin="org.dita.pdf2"/>
  <transtype name="print-pdf" extends="pdf" desc="PDF on A4 paper"/>
  <feature extension="dita.transtype.print" value="print-pdf"/>
  <feature extension="ant.import" file="integrator.xml"/>
</plugin>
Tip: For a complete sample plug-in with all required code, see Example: Creating a simple PDF plug-in.
Figure 2. Defining new parameters

If your custom transformation type supports custom parameters, they can be defined in nested <param> elements within the <transtype> element.

While the org.dita.html5 plug-in was separated from common-html in version 2.4, the following example shows how earlier versions of that plug-in used the <transtype> element to extend the common HTML transformation with a new html5 transformation type and define a new nav-toc parameter with three possible values:

<transtype name="html5" extends="common-html" desc="HTML5">
  <param name="nav-toc" type="enum" 
         desc="Specifies whether to generate navigation in topic pages.">
    <val default="true" desc="No TOC">none</val>
    <val desc="Partial TOC that shows the current topic">partial</val>
    <val desc="Full TOC">full</val>
  </param>
</transtype>