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 * Copyright (C) 1997-2015 by Dimitri van Heesch.
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/*! \page customize Customizing the output

\tableofcontents

Doxygen provides various levels of customization. 
The section \ref minor_tweaks "Minor Tweaks" discusses what to 
do if you want to do minor tweaking to the look and feel of the output. 
The section \ref layout "Layout" show how to reorder and hide certain 
information on a page. 
The section \ref xmlgenerator "XML output" show how to generate 
whatever output you want based on the XML output produced by doxygen.

\section minor_tweaks Minor Tweaks

The next subsections describe some aspects that can be tweaked with
little effort.

\subsection minor_tweaks_colors Overall Color

To change the overall color of the HTML output doxygen provides three options
- \ref cfg_html_colorstyle_hue "HTML_COLORSTYLE_HUE"
- \ref cfg_html_colorstyle_sat "HTML_COLORSTYLE_SAT"
- \ref cfg_html_colorstyle_gamma "HTML_COLORSTYLE_GAMMA"

to change the hue, saturation, and gamma correction of the colors respectively.

For your convenience the GUI frontend \ref doxywizard_usage "Doxywizard" 
has a control that allows you to see the effect of changing the values of these options 
on the output in real time.

\subsection minor_tweaks_treeview Navigation

By default doxygen shows navigation tabs on top of every HTML page,
corresponding with the following settings:

- \ref cfg_disable_index "DISABLE_INDEX" = \c NO
- \ref cfg_generate_treeview "GENERATE_TREEVIEW" = \c NO

you can switch to an interactive navigation tree as sidebar using

- \ref cfg_disable_index "DISABLE_INDEX" = \c YES
- \ref cfg_generate_treeview "GENERATE_TREEVIEW" = \c YES

or even have both forms of navigation:

- \ref cfg_disable_index "DISABLE_INDEX" = \c NO
- \ref cfg_generate_treeview "GENERATE_TREEVIEW" = \c YES

if you already use an external index (i.e. have one of the following
options enabled
\ref cfg_generate_htmlhelp "GENERATE_HTMLHELP",
\ref cfg_generate_eclipsehelp "GENERATE_ECLIPSEHELP",
\ref cfg_generate_qhp "GENERATE_QHP", or
\ref cfg_generate_docset "GENERATE_DOCSET")
then you can also disable all indices, like so:

- \ref cfg_disable_index "DISABLE_INDEX" = \c YES
- \ref cfg_generate_treeview "GENERATE_TREEVIEW" = \c NO

\subsection minor_tweaks_dynsection Dynamic Content

To make the HTML output more interactive, doxygen provides a number of options
that are disabled by default:
- enabling \ref cfg_html_dynamic_sections "HTML_DYNAMIC_SECTIONS" will make
  doxygen hide certain content (like graphs) in the HTML by default, 
  and let the reader expand these sections on request.
- enabling \ref cfg_have_dot "HAVE_DOT" along 
  with \ref cfg_interactive_svg "INTERACTIVE_SVG" while setting 
  \ref cfg_dot_image_format "DOT_IMAGE_FORMAT" to \c svg, will make doxygen
  produce SVG images that will allow the user to zoom and pan (this only
  happens when the size of the images exceeds a certain size).

\subsection minor_tweaks_header_css Header, Footer, and Stylesheet changes

To tweak things like fonts or colors, margins, or other look \& feel
aspects of the HTML output in detail, you can create a different 
<a href="https://www.w3schools.com/css/default.asp">cascading style sheet</a>. 
You can also let doxygen use a custom header and footer for each HTML 
page it generates, for instance to make the output conform to the style 
used on the rest of your web site.

To do this first run doxygen as follows:
\verbatim
doxygen -w html header.html footer.html customdoxygen.css 
\endverbatim

This will create 3 files:
- header.html is a HTML fragment which doxygen normally uses to start
  a HTML page. Note that the fragment ends with a body tag and that is
  contains a couple of commands of the form \$word. These will be replaced
  by doxygen on the fly. 
- footer.html is a HTML fragment which doxygen normally uses to end 
  a HTML page. Also here special commands can be used. This file contain the 
  link to www.doxygen.org and the body and html end tags.
- customdoxygen.css is the default cascading style sheet
  used by doxygen. It is recommended only to look into this file and overrule
  some settings you like by putting them in a separate stylesheets and
  referencing those extra files
  via \ref cfg_html_extra_stylesheet "HTML_EXTRA_STYLESHEET".

You should edit these files and then reference them from the config file.
- \ref cfg_html_header "HTML_HEADER" = \c header.html
- \ref cfg_html_footer "HTML_FOOTER" = \c footer.html
- \ref cfg_html_extra_stylesheet "HTML_EXTRA_STYLESHEET" = \c my_customdoxygen.css

\note it is not longer recommended to use \ref cfg_html_stylesheet "HTML_STYLESHEET",
as it make it difficult to upgrade to a newer version of doxygen. Use
\ref cfg_html_extra_stylesheet "HTML_EXTRA_STYLESHEET" instead.

See the documentation of the \ref cfg_html_header "HTML_HEADER" tag
for more information about the possible meta commands you can use inside
your custom header.

\note You should not put the style sheet in the HTML output directory. Treat
it as a source file. Doxygen will copy it for you. 

\note If you use images or other external content in a custom header you
need to make sure these end up in the HTML output directory yourself,
for instance by writing a script that runs doxygen can then copies the
images to the output.

\warning The structure of headers and footers may change after upgrading to
a newer version of doxygen, so if you are using a custom header or footer, 
it might not produce valid output anymore after upgrading. 

\section layout Changing the layout of pages

In some cases you may want to change the way the output is structured.
A different style sheet or custom headers and footers do not help in such 
case.

The solution doxygen provides is a layout file, which you can
modify and doxygen will use to control what information is presented, 
in which order, and to some extent also how information is presented.
The layout file is an XML file. 

The default layout can be generated
by doxygen using the following command:
\verbatim
doxygen -l 
\endverbatim
optionally the name of the layout file can be specified, if omitted
\c DoxygenLayout.xml will be used.

The next step is to mention the layout file in the config file
\verbatim
LAYOUT_FILE = DoxygenLayout.xml
\endverbatim
To change the layout all you need to do is edit the layout file.

The toplevel structure of the file looks as follows:
\verbatim
<doxygenlayout version="1.0">
  <navindex>
    ...
  </navindex>
  <class>
    ...
  </class>
  <namespace>
    ...
  </namespace>
  <file>
    ...
  </file>
  <group>
    ...
  </group>
  <directory>
    ...
  </directory>
</doxygenlayout>
\endverbatim

The root element of the XML file is \c doxygenlayout, it has an attribute named
\c version, which will be used in the future to cope with changes that are
not backward compatible.

The first section, identified by the \c navindex element, represents the 
layout of the navigation tabs displayed at the top of each HTML page. At the
same time it also controls the items in the navigation tree in case
\ref cfg_generate_treeview "GENERATE_TREEVIEW" is enabled. 
Each tab is represented by a \c tab element in the XML file.

You can hide tabs by setting the \c visible attribute to \c no. 
You can also override the default title of a tab by specifying it as 
the value of the \c title attribute. If the title field is the empty string
(the default) then doxygen will fill in an appropriate language specific title.

You can reorder the tabs by moving the tab elements in the XML file
within the \c navindex element and even change the tree structure. 
Do not change the value of the \c type attribute however. 
Only a fixed set of types are supported, each representing a link to a 
specific index.

You can also add custom tabs using a type with name "user". Here is an
example that shows how to add a tab with title "Google" pointing to 
www.google.com:

\verbatim
  <navindex>
    ...
    <tab type="user" url="http://www.google.com" title="Google"/>
    ...
  </navindex>
\endverbatim

The url field can also be a relative URL. If the URL starts with \@ref
the link will point to a documented entities, such as a class, a function, 
a group, or a related page. Suppose we have defined a page using \@page with 
label mypage, then a tab with label "My Page" to this page would look 
as follows:

\verbatim
  <navindex>
    ...
    <tab type="user" url="@ref mypage" title="My Page"/>
    ...
  </navindex>
\endverbatim

You can also group tabs together in a custom group using a tab with
type "usergroup". The following example puts the above tabs in a user
defined group with title "My Group":

\verbatim
  <navindex>
    ...
    <tab type="usergroup" title="My Group">
      <tab type="user" url="http://www.google.com" title="Google"/>
      <tab type="user" url="@ref mypage" title="My Page"/>
    </tab>
    ...
  </navindex>
\endverbatim

Groups can be nested to form a hierarchy. 

By default a usergroup entry in the navigation tree is a link to
a landing page with the contents of the group. You can link to a
different page using the `url` attribute just like you can for the
`<tab>` element and prevent any link using `url="[none]"`, i.e.

\verbatim
   <tab type="usergroup" title="Group without link" url="[none]">
   ...
   </tab>
\endverbatim

The elements after \c navindex represent the layout of the different 
pages generated by doxygen:
- The \c class element represents the layout of all pages generated for
  documented classes, structs, unions, and interfaces.
- The \c namespace element represents the layout of all pages generated for
  documented namespaces (and also Java packages).
- The \c file element represents the layout of all pages generated for
  documented files.
- The \c group element represents the layout of all pages generated for
  documented groups (or modules).
- The \c directory element represents the layout of all pages generated for
  documented directories.

Each XML element within one of the above page elements represents a certain
piece of information. Some pieces can appear in each type of page,
others are specific for a certain type of page.
Doxygen will list the pieces in the order in which they appear 
in the XML file. 

The following generic elements are possible for each page:
<dl>
<dt>\c briefdescription
  <dd>Represents the brief description on a page.
<dt>\c detaileddescription
  <dd>Represents the detailed description on a page.
<dt>\c authorsection
  <dd>Represents the author section of a page (only used for man pages).
<dt>\c memberdecl
  <dd>Represents the quick overview of members on a page (member declarations).
      This elements has child elements per type of member list.
      The possible child elements are not listed in detail in the document, 
      but the name of the element should be a good indication of the type 
      of members that the element represents.
<dt>\c memberdef
  <dd>Represents the detailed member list on a page (member definition).
      Like the \c memberdecl element, also this element has a number of 
      possible child elements. 
</dl>

The class page has the following specific elements:
<dl>
<dt>\c includes
  <dd>Represents the include file needed to obtain the definition for 
      this class.
<dt>\c inheritancegraph
  <dd>Represents the inheritance relations for a class. 
      Note that the CLASS_DIAGRAM option determines
      if the inheritance relation is a list of base and derived classes or
      a graph. 
<dt>\c collaborationgraph
  <dd>Represents the collaboration graph for a class.
<dt>\c allmemberslink
  <dd>Represents the link to the list of all members for a class.
<dt>\c usedfiles
  <dd>Represents the list of files from which documentation for the class was
      extracted.
</dl>

The file page has the following specific elements:
<dl>
<dt>\c includes
  <dd>Represents the list of \#include statements contained in this file.
<dt>\c includegraph
  <dd>Represents the include dependency graph for the file.
<dt>\c includedbygraph
  <dd>Represents the included by dependency graph for the file.
<dt>\c sourcelink
  <dd>Represents the link to the source code of this file.
</dl>

The group page has a specific \c groupgraph element which represents the
graph showing the dependencies between groups.

Similarly, the directory page has a specific \c directorygraph element 
which represents the graph showing the dependencies between the directories 
based on the \#include relations of the files inside the directories.

Some elements have a \c visible attribute which can be 
used to hide the fragment from the generated output, by setting the attribute's
value to "no". You can also use the value of a configuration option to 
determine the visibility, by using 
its name prefixed with a dollar sign, e.g.
\verbatim
  ...
  <includes visible="$SHOW_INCLUDE_FILES"/>
  ...
\endverbatim
This was mainly added for backward compatibility.
Note that the \c visible attribute is just a hint for doxygen. 
If no relevant information is available for a certain piece it is 
omitted even if it is set to \c yes (i.e. no empty sections are generated). 

Some elements have a \c title attribute. This attribute can be used
to customize the title doxygen will use as a header for the piece.

@warning at the moment you should not remove elements from the layout file
as a way to hide information. Doing so can cause broken links in the 
generated output!


\section xmlgenerator Using the XML output

If the above two methods still do not provide enough flexibility, you
can also use the XML output produced by doxygen as a basis to
generate the output you like. To do this set GENERATE_XML to YES.

The XML output consists of an index file named \c index.xml which
lists all items extracted by doxygen with references to the other XML files
for details. The structure of the index is described by a schema file
\c index.xsd. All other XML files are described by the schema file 
named \c compound.xsd. If you prefer one big XML file 
you can combine the index and the other files using the 
XSLT file \c combine.xslt.

You can use any XML parser to parse the file or use the one that can be found
in the \c addon/doxmlparser directory of doxygen source distribution. 
Look at \c addon/doxmlparser/include/doxmlintf.h for the interface of the
parser and in \c addon/doxmlparser/example for examples.

The advantage of using the doxmlparser is that it
will only read the index file into memory and then only those XML 
files that you implicitly load via navigating through the index. As a 
result this works even for very large projects where reading all XML
files as one big DOM tree would not fit into memory.

See <a href="https://github.com/michaeljones/breathe">the Breathe project</a> for
an example that uses doxygen XML output from Python to bridge it with the 
<a href="http://www.sphinx-doc.org/en/stable/">Sphinx</a> document generator.


\htmlonly
Go to the <a href="custcmd.html">next</a> section or return to the
 <a href="index.html">index</a>.
\endhtmlonly

 */