===============
 Hacking Guide
===============

1. Introduction

  The GIMP documentation project uses docbook xml files to create the GIMP
  manual / online help. Since there are different approaches how to create
  and edit such files as well as different tools involved, there is a strong
  need for the xml files to be well formatted.
  Additionally there are a couple of technical reasons (diff, git) that
  suggest a general style guide for the xml files. This is a recommendation
  for such a style guide. It is mainly based on the styles that can be found
  in the xml files that build the current documentation, as well as on the
  discussion on the gimp-doc mailing list.

2. XML style guide by rules

  §1. General
  §1.1. All docbook files for the documentation need to be well formed and
    have to comply validation against
    http://www.docbook.org/xml/4.3/docbookx.dtd.
  §1.2. All docbook files use UTF-8 character encoding.

  §2. Length of lines
  §2.1. The length of line should not exceed 80 characters. Exceptions
    might be made for text that is technically not able to be wrapped
    (Chinese text does rarely contain space characters, so it can't be
    wrapped without introducing unwanted whitespaces) and attributes of
    elements.

  §3. Elements and new lines
  §3.1. Element tagnames are written all lowercase.
  §3.2. All tags (opening and closing) start on a new line. For
    exceptions see §3.3.
  §3.3. Elements listed in Appendix I (inline elements) do not need to
    start their opening and closing tags on a new line, as long as their
    content does not exceed 80 characters.

  §4. Element attributes
  §4.1. Element attributes are written all lowercase.
  §4.2. Element attributes values are enclosed in double quotes ( " ).

  §5. Indentation
  §5.1. Use only Space characters for indentation. Tab characters should not
    be used.
  §5.2. Indentation width is two spaces.
  §5.3. Indentation is done for the content of all tags that start a new line.
  §5.4. Indentation should be increased if an element is a child of the
    previous element.

3 XML style guide by example

  Example for §1 General
  Following the rules in §1 each xml file of the GIMP manual starts with:

  <?xml version='1.0' encoding='UTF-8'?>
  <!DOCTYPE abcd
  PUBLIC '-//OASIS//DTD DocBook XML V4.3//EN'
  'http://www.docbook.org/xml/4.3/docbookx.dtd'>

  where abcd is the root element of the file (usually book, sect1 of sect2).

  Example for §2. Length of lines
  // to be done

  Example for §3. Elements and new lines
  // to be done

  Example for §4. Element attributes
  // to be done

  Example for §5. Indentation
  // to be done

Appendix I Inline elements
  <abbrev>
  <accel>
  <acronym>
  <action>
  <anchor>
  <application>
  <citation>
  <citerefentry>
  <citetitle>
  <classname>
  <command>
  <computeroutput>
  <constant>
  <database>
  <email>
  <emphasis>
  <envar>
  <errorcode>
  <errorname>
  <filename>
  <firstterm>
  <footnote>
  <forignphrase>
  <function>
  <guibutton>
  <guiicon>
  <guilabel>
  <guimenu>
  <guimenuitem>
  <guisubmenu>
  <glossterm>
  <hardware>
  <inlineequation>
  <inlinegraphic>
  <interface>
  <interfacedefinition>
  <keycap>
  <keycode>
  <keycombo>
  <keysym>
  <link>
  <literal>
  <markup>
  <medialabel>
  <menuchoice>
  <mousebutton>
  <msgtext>
  <olink>
  <option>
  <optional>
  <parameter>
  <phrase>
  <prompt>
  <property>
  <quote>
  <replaceable>
  <returnvalue>
  <shortcut>
  <structfield>
  <structname>
  <subsrcipt>
  <superscript>
  <symbol>
  <systemitem>
  <token>
  <trademark>
  <type>
  <ulink>
  <userinput>
  <varname>
  <wordasword>
  <xref>
