## 7. Preprocessing options

Converting a DITA document to formats such as HTML, PDF, RTF, etc, comprises two steps. First step consists in preprocessing the DITA document. Second step consists in translating the preprocessed DITA document to the other format by the means of XSLT stylesheets.
The XSLT stylesheets are parameterized by using Options → Customize Configuration → Change Document Conversion Parameters, while the preprocessor is parameterized by using Options → Customize Configuration → Preprocessing Options. The latter menu item displays a dialog box which is described in this section.
Figure 6. The Preprocessing Options dialog box
The top combobox allows to select the group of options to be edited. Each group of options is completely separated from the other. For example, specifying that an index is to be generated as backmatter for group "Convert to single-page XHTML" will have an effect when you'll use Map → Convert Document → Convert to XHTML [one page] and no effect at all when you'll use Map → Convert Document → Convert to HTML Help or when you'll use Topic → Convert Document → Convert to XHTML [one page] (because there is a separate "Convert to single-page XHTML" group of options for the Map, BookMap and Topic configurations).

Default language
  Specifies the main language of the document. Examples: en, en-US, fr, fr-CA. This information is needed in order to sort the index entries. By default, this information is taken from the xml:lang attribute of the root element of the topic map (if any, "en" otherwise).
Table of Contents
  Specifies whether to automatically generate a Table of Contents and, if a Table of Contents is to be generated, where to generate it. Frontmatter means at the beginning of the document. Backmatter means at the end of the document.
  This option, like List of Figures, List of Tables, List of Examples and Index, is mainly useful when working with maps or individual topics. When working with a bookmap, the preferred way to specify the location, if any, of a Table of Contents is to do it in the bookmap itself. In all cases, what's specified in the bookmap has priority over the value of this option.
List of Figures
  Specifies whether to automatically generate a List of Figures and, if a List of Figures is to be generated, where to generate it.
List of Tables
  Specifies whether to automatically generate a List of Tables and, if a List of Tables is to be generated, where to generate it.
List of Examples
  Specifies whether to automatically generate a List of Examples and, if a List of Examples is to be generated, where to generate it.
Index
  Specifies whether to automatically generate an Index and, if an Index is to be generated, where to generate it.
Copy images to
  Copy the image files referenced in the topics to specified directory. If specified path is relative, it is relative to the output directory.
  In the above screenshot, "images/*.{png,jpg,jpeg,gif}" means:
  - copy to directory images/, relative to the output directory,
  - as is (that is, without having to convert the image to another image format),
  - all the images referenced in the document source, having a png, jpg, jpeg or gif filename extension.
  - Any image referenced in the document source having a filename extension other than png, jpg, jpeg or gif (e.g. svg, tif) will be automatically converted to an image having a png, jpg, jpeg or gif filename extension.
  When this field is left empty, the generated document will reference the image files using absolute URLs. This is harmless for PDF, RTF, etc, files because at the end of the conversion process, such files will embed a copy of the image files. However, this is rarely what is wanted for HTML-based formats (XHTML, Java Help, HTML Help, Eclipse Help, EPUB, etc).
Chunk mode
  Allowed values are Automatic, Single and None.
  Chunk Automatic means: ignore the chunk specification found in the topic map and output a single chunk for the Print medium; honor the chunk specification for the Screen medium.
  Chunk None means ignore the chunk specification found in the topic map and output a single chunk. As explained above, chunk None is implicit for some formats (PostScript, PDF, RTF, etc).
  Both the None and Single values may be used to force the generation of a single output file. Chunk Single allows to reuse a map designed to output multiple HTML pages in order to generate a single HTML file or a PDF file.
Target medium
  Explicitly specifies the output medium: Screen (XHTML, HTML Help, Eclipse Help, etc) or Print (PDF, RTF, etc). By default, the output media is guessed using the extension of the output file.
Preprocessor messages
  Specifies the level of verbosity of the preprocessor. Allowed values are (from not verbose to very verbose): None, Information, Verbose, Debug.

Some fields may be ``grayed out'' (disabled). This happens in two cases:

1. The DITA configuration has been customized by the local guru. This automatically prevents the end user from making any change to the preprocessing options.
2. Changing the values of some options (e.g. Target medium) would break the stock configuration.