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[bbtk.git] / kernel / doc / bbtkPackageDevelopersGuide / bbtkPackageDevelopersGuide.tex

% ==========================================
\documentclass[11pt,final,a4paper]{article}
\input{config.tex}
\begin{document}
\bbtkGuide[Package Developers' Guide]
\newpage
% ==========================================




% ==========================================
\section{Introduction}
% ==========================================

This guide describes how to 
create new \bbtk packages and black boxes. 
How to use them is described in \bbtk Users' guide. 

Any black box must be included in a \bbtk package, 
that is in a particular shared library which can be loaded 
dynamically by \bbtk, either in \CPP code or in \bbs scripts 
with the commands \texttt{include} or \texttt{load}.
The steps to create new boxes are thus to :

\begin{enumerate}
\item \textbf{Create a new package. }
This is described in section \ref{CreatePackage}.

\item \textbf{Describe your new box.}
You can do it either :
\begin{itemize}
\item In \CPP code. You will have to write the class for 
your box, mostly using \bbtk macros.  
\item In \xml code. 
When configuring your project with \cmake, 
the utility \bbfy will then generate the corresponding \CPP code. 
\end{itemize}

This is described in section \ref{CreateBlackBox}.

\end{enumerate}

% ==========================================
\section{Creating a new package}
\label{CreatePackage}
% ==========================================

% ==========================================
\subsection{Creating the file tree}
% ==========================================
Before defining any black box you  
have to create a package, or more precisely  
the source files which will allow you to generate the package 
(compile and link the shared library) and may be install it. 

The \bbtk command line application \bbCreatePackage 
allows to create the basic file architecture 
to start the development of a new black box package.
Type \bbCreatePackage in a console to get its usage :
\begin{verbatim}
bbCreatePackage <package-path> <package-name> [author] [description]
\end{verbatim}

\bbStudio also offers a graphical interface to the \bbCreatePackage 
application. 
You can run it with the menu \texttt{Tools $>$ Create Package}. 

In both cases (using the command line tool or \bbStudio interface), 
you have to choose : 

\begin{itemize}
\item The {\bf directory} of your new package. 
Two cases occur :
\begin{itemize}
\item The black boxes you want to create are based on 
a processing code (\CPP classes or \C functions) which 
is in an existing project handled by \cmake
and you want the new package to be part of your existing project. 
You will have to create your new package into the source tree of your 
project and add a \texttt{SUBDIRS} command in the \texttt{CMakeLists.txt} 
file of the parent directory of your package.
\item You do not have an already existing project (you want 
to create the new boxes from scratch) or you want/are imposed  
that the existing project remain external to the package project.
You will have to create your new package in a new location and 
may be include/link against existing libraries. 
\end{itemize}

\item The {\bf name} of your new package. 
This name will be used to load the package in \CPP and \bbs scripts.
\end{itemize}

You must also provide the \texttt{author} list 
and a \texttt{description} which will be used for your package documentation.

After running \bbCreatePackage or clicking 'Run' in \bbStudio interface 
you should get a file structure like this (Linux users can verify it with the \texttt{tree} command):
\begin{verbatim}
    NEW_PACKAGE
    |-- CMakeLists.txt
    |-- Configure.cmake
    |-- PackageConfig.cmake.in
    |-- README.txt
    |-- UsePackage.cmake.in
    |-- bbs
    |   |-- CMakeLists.txt
    |   |-- appli
    |   |   `-- README.txt
    |   `-- boxes
    |       `-- README.txt
    |-- data
    |   `-- CMakeLists.txt
    |-- doc
    |   |-- CMakeLists.txt
    |   |-- bbdoc
    |   |   |-- CMakeLists.txt
    |   |   `-- header.html.in
    |   `-- doxygen
    |       |-- CMakeLists.txt
    |       |-- DoxyMainPage.txt.in
    |       `-- Doxyfile.txt.in
    `-- src
        `-- CMakeLists.txt
\end{verbatim}

You can then :
\begin{itemize}
\item Edit the root CMakeLists.txt file to customize your package build settings (see \ref{RootCMakeLists} below)

\item Put your c++/xml boxes sources in 'src'.
 
  Please use the convention : If the name of your package is Pack and the name of your box is Box then name the source files bbPackBox.\{h;cxx;xml\}.

\item Put your script-defined boxes (complex boxes) in 'bbs/boxes'. 

  Please use the convention : If the name of your box is 'Box' then call the file 'bbBox.bbs' to let others know that the script defines a complex black box type.

\item Put your script-defined applications in 'bbs/appli'. 

  Please use the convention : Do not prepend 'bb' to the files.

\item Put your data in 'data'. 
Any data put there will be installed and accessible in your scripts : 
the package data path is provided by the box 
\texttt{std::PrependPackageDataPath}.

\item You can customize the header of your package html doc by editing the file 'doc/bbdoc/header.html.in'. You must put html code in this file (or edit it with an html editor). You can include images or links to other html pages. The images and pages must be put in the folder 'doc/bbdoc' and will be properly installed. The same way, you can link to these images or pages in your boxes descriptions without giving any path. If you create subdirs for your material then you have to install the materials yourself by editing the CMakeLists.txt and links must use paths relative to 'doc/bbdoc'.

\item You can customize the main page of your doxygen doc by editing the file 'doc/doxygen/DoxyMainPage.txt.in'.
\end{itemize}

\subsection{Configuring the root \texttt{CMakeLists.txt}}
\label{RootCMakeLists}

First you must configure your new package build settings, by editing the file 
\texttt{CMakeLists.txt} in the package root directory.
This file contains :

\begin{file}{CMakeLists.txt}
\small
\begin{verbatim}
#===========================================================================
# CMAKE SETTINGS FOR BUILDING A BBTK PACKAGE
#===========================================================================

#===========================================================================
# THE NAME OF THE BBTK PACKAGE
SET(BBTK_PACKAGE_NAME MyPackage)
#===========================================================================

#===========================================================================
# IF IT IS A STANDALONE PROJECT UNCOMMENT NEXT LINE TO DECLARE YOUR PROJECT
# PROJECT(bb${BBTK_PACKAGE_NAME})
#===========================================================================

#===========================================================================
# PACKAGE AUTHOR
# !!! NO COMMA ALLOWED !!!
SET(${BBTK_PACKAGE_NAME}_AUTHOR "myself")
#===========================================================================

#===========================================================================
# PACKAGE DESCRIPTION
SET(${BBTK_PACKAGE_NAME}_DESCRIPTION "The kinkiest stuff you ve ever seen.")
#===========================================================================

#===========================================================================
# PACKAGE VERSION NUMBER 
SET(${BBTK_PACKAGE_NAME}_MAJOR_VERSION 1)
SET(${BBTK_PACKAGE_NAME}_MINOR_VERSION 0)
SET(${BBTK_PACKAGE_NAME}_BUILD_VERSION 0)
#===========================================================================

#===========================================================================
# UNCOMMENT EACH LIBRARY NEEDED (WILL BE FOUND AND USED AUTOMATICALLY)
# SET(${BBTK_PACKAGE_NAME}_USE_VTK  ON)
# SET(${BBTK_PACKAGE_NAME}_USE_ITK  ON)
# SET(${BBTK_PACKAGE_NAME}_USE_GDCM ON)
# SET(${BBTK_PACKAGE_NAME}_USE_GSMIS ON)
# SET(${BBTK_PACKAGE_NAME}_USE_WXWIDGETS ON)
#===========================================================================

#===========================================================================
# LIST HERE THE OTHER bbtk PACKAGES NEEDED
# (WILL BE FOUND AND USED AUTOMATICALLY)
SET(${BBTK_PACKAGE_NAME}_USE_PACKAGES 
  # std
  # wx
  # itk
  # vtk
  # ...
  )
#===========================================================================

#===========================================================================
# THE SOURCES OF THE PACKAGE
# EITHER UNCOMMENT NEXT LINE TO COMPILE ALL .cxx OF THE src DIRECTORY :
SET(${BBTK_PACKAGE_NAME}_COMPILE_ALL_CXX ON)
# ... OR LIST THE FILES TO COMPILE MANUALLY :
#SET(${BBTK_PACKAGE_NAME}_SOURCES
# LIST HERE THE FILES TO COMPILE TO BUILD THE LIB
# E.G. TO COMPILE "toto.cxx" ADD "toto" (NO EXTENSION)
# THE PATH MUST BE RELATIVE TO THE src FOLDER
#    )
#===========================================================================

#===========================================================================
# THE xml SOURCES OF THE PACKAGE
# EITHER UNCOMMENT NEXT LINE TO bbfy ALL .xml OF THE src DIRECTORY :
SET(${BBTK_PACKAGE_NAME}_COMPILE_ALL_XML ON)
# ... OR LIST THE FILES TO COMPILE MANUALLY :
#SET(${BBTK_PACKAGE_NAME}_XML_SOURCES
# LIST HERE THE FILES TO bbfy TO BUILD THE LIB
# E.G. TO bbfy "toto.xml" ADD "toto" (NO EXTENSION)
# THE PATH MUST BE RELATIVE TO THE src FOLDER
#    )
#===========================================================================

#===========================================================================
# THE SCRIPT-DEFINED BOXES OF THE PACKAGE (bbs)
# EITHER UNCOMMENT NEXT LINE TO INCLUDE ALL .bbs OF THE bbs/boxes DIRECTORY :
SET(${BBTK_PACKAGE_NAME}_INCLUDE_ALL_BBS_BOXES ON)
# ... OR LIST THE FILES TO INCLUDE MANUALLY :
# SET(${BBTK_PACKAGE_NAME}_BBS_BOXES
# LIST HERE THE bbs FILES TO INCLUDE 
# E.G. TO INCLUDE "boxes/bbtoto.bbs" ADD "boxes/bbtoto" (NO EXTENSION)
# !! THE PATH MUST BE RELATIVE TO THE bbs FOLDER !!
#)
#===========================================================================

#===========================================================================
# THE SCRIPT-DEFINED APPLICATIONS OF THE PACKAGE (bbs)
# EITHER UNCOMMENT NEXT LINE TO INCLUDE ALL .bbs OF THE bbs/appli DIRECTORY :
SET(${BBTK_PACKAGE_NAME}_INCLUDE_ALL_BBS_APPLI ON)
# ... OR LIST THE FILES TO INCLUDE MANUALLY :
# SET(${BBTK_PACKAGE_NAME}_BBS_APPLI
# LIST HERE THE bbs FILES TO INCLUDE 
# E.G. TO INCLUDE "appli/testToto.bbs" ADD "appli/testToto" (NO EXTENSION)
# !! THE PATH MUST BE RELATIVE TO THE bbs FOLDER !!
#)
#===========================================================================

#===========================================================================
SET(${BBTK_PACKAGE_NAME}_INCLUDE_DIRS
  # LIST HERE YOUR ADDITIONAL INCLUDE DIRECTORIES 
  # EXCEPT :
  #  - src
  #  - bbtk dirs
  #  - automatically handled libraries or packages : wx, vtk... (see above)
  #  - the dirs automatically set by other libraries found by FIND_PACKAGE
  )
#===========================================================================

#===========================================================================
SET(${BBTK_PACKAGE_NAME}_LIBS 
  # LIST HERE THE ADDITIONAL LIBS TO LINK AGAINST
  # EXCEPT : the same libs than for INCLUDE_DIRS 
  )
#===========================================================================

#===========================================================================
# IF NEEDED : UNCOMMENT NEXT LINE 
# AND LIST ADDITIONNAL DIRECTORIES 
# IN WHICH TO LOOK FOR LIBRARIES TO LINK AGAINST
# LINK_DIRECTORIES()
#===========================================================================

#===========================================================================
# SET TO TRUE TO HAVE INFORMATION ON LIBRARIES FOUND DURING CMAKE CONFIGURE
SET(FIND_PACKAGE_VERBOSE TRUE)
#===========================================================================

#===========================================================================
# END OF USER SECTION
#===========================================================================

#===========================================================================
# Include configuration script
INCLUDE(Configure.cmake)
#===========================================================================

#===========================================================================
# EOF
#===========================================================================

\end{verbatim}
\end{file}

The comments in the file should be easily understandable !
In this file, 
you can see some of the informations you supplied in previous step:
\begin{itemize}
  \item The \textbf{name} of your package. This will be the name used to load it in \bbi. The shared library however will be called \texttt{bb}name hence on 
    \lin the object file will be called \texttt{libbb}name\texttt{.so} 
    and on \win it  will be called \texttt{bb}name\texttt{.dll}.
  \item The \textbf{author(s)} of the package. Preferably provide e-mail adresses.
  \item A \textbf{description} of the package, which will appear in the help of your package or in its html documentation automatically generated by \bbtk.  
\end{itemize}

You can additionaly set :
\begin{itemize}
\item The \textbf{version} of the package.

\item The \textbf{libraries used} by the package : \vtk, \itk, \gdcm, \gsmis, \wx. The mecanisms to find these libraries, their sources and to link against them are automatically handled by the \cmake files installed by \bbCreatePackage. You just have to uncomment a line to use one of these libraries.
\item The \textbf{core \bbtk packages used} by the package as \CPP libraries
(if you need to use the black boxes of these packages in your \CPP code, 
i.e. include some header and link with the library). 
The mecanisms to find these libraries, 
their sources and to link against them are automatically handled 
by the \cmake files installed by \bbCreatePackage. 
You just have to uncomment a line to use one of these libraries.

\item The \textbf{\CPP sources} of the package : you can list each input \CPP 
file explicitly or tell \cmake to include in the project all the \CPP files 
of the 'src' directory (default).

\item The \textbf{\xml sources} of the package : you can list each input \xml
file explicitly or tell \cmake to include in the project all the \xml files 
of the 'src' directory (default).

\item The \textbf{boxes \bbs sources} of the package : you can list each 
input \bbs
file explicitly or tell \cmake to include in the project \emph{all} 
the \bbs files of the 'bbs/boxes' directory (default, recommanded). 

\item The \textbf{appli \bbs sources} of the package : 
you can list each input \bbs
file explicitly or tell \cmake to include in the project \emph{all} 
the \bbs files of the 'bbs/appli' directory (default, recommanded). 

\item \textbf{Additional include directories}. Set it if your package needs to include source files which are not in the package directory, typically if it depends on another library which is not one the libraries automatically handled (\vtk, \itk...) and which you did not find with the 
\texttt{FIND\_PACKAGE} mechanism of \cmake.

\item \textbf{Additional libraries} to link against. Set it if your package needs to link against another library which is not one the libraries automatically handled (\vtk, \itk...) and which you did not find with the 
\texttt{FIND\_PACKAGE} mechanism of \cmake.

\item \textbf{Additional link directories} in which to find libraries not 
automatically handled and which you did not find with the 
\texttt{FIND\_PACKAGE} mechanism of \cmake. 

\end{itemize}

Of course, this is only a framework and you can add any other \cmake commands
in the file.

% ==========================================
\section{Creating a new box}
\label{CreateBlackBox}
% ==========================================

% ==========================================
\subsection{Principles}
% ==========================================

% ==========================================
\subsubsection{\texttt{C++} or \texttt{XML} ?}
% ==========================================
There are two ways to create a new black box in an existing package :
\begin{itemize}
\item Write an \xml description file which will be automatically 
translated in \CPP by the \bbfy application during build (recommanded).
\item Write the \CPP code of the box using \bbtk macros.
\end{itemize}

% ==========================================
\subsubsection{From which \bbtk class inherit ?}
% ==========================================

Apart from the choice of the description langage to use, 
there is an important choice to do concerning the implementation of the box. 
In \CPP, a black box is nothing but a class which has the standard 
interface of all black boxes : what's its name ? inputs ? outputs ? and so on. 

The abstract description of this interface is done in the class 
\texttt{bbtk::BlackBox} of the \bbtk library 
and is implemented in its children classes : 
\texttt{bbtk::AtomicBlackBox} and \texttt{bbtk::WxBlackBox} 
\footnote{all the classes of the \bbtk library are in a \emph{namespace} 
called \texttt{bbtk} 
and the \CPP header of a class called \texttt{NameOfAClass} is 
in the file called \texttt{bbtkNameOfAClass.h}}.

To create a new black box, you have to inherit one of these two  
concrete classes in order to inherit the black box interface and a 
particular implementation of this interface. 

If your black box is a \emph{Widget} black box, 
that is a black box which has (or is) 
a piece of a graphical interface based on the \wx library,
then it must inherit the class \texttt{bbtk::WxBlackBox}. 

Concretely, a \texttt{bbtk::WxBlackBox} is associated 
a \texttt{wxWindow} and must be able to return a pointer to it. 
If your black box is not a widget black box 
(that is : doesn't returns a pointer to a \texttt{wxWindow}),
 it must inherit from \texttt{bbtk::AtomicBlackBox}.
NOTE : \emph{modal dialogs} 
which are created and destroyed at the end of the process 
method of the box are NOT \texttt{WxBlackBoxes} : 
they do not return a \texttt{wxWindow}, 
see the code of \texttt{wx::FileSelector} for example.

% ==========================================
\subsubsection{Inherit or encapsulate ?}
% ==========================================

Now, your black box will do something (hopefully !). 
When you decide to write a new black box, 
you should be in one of these three cases :
\begin{enumerate}
\item You already have a \texttt{C}-like function which 
does the processing that you wish to 'blackboxify' (bbfy in short).
\item You already have a \CPP class which 
does the processing that you wish to 'blackboxify'
\item You start from scratch without any existing code
\end{enumerate}

The idea of \BBTK is to embed processing codes into 
\CPP objects which have a standard and generic interface - 
namely black boxes - to be able to chain arbitrary 
processes afterwards. 

In \CPP, in order to embed an existing processing \emph{class}  
into a standard interface you only have two possibilities :
\begin{enumerate}
\item {\bf Inherit} the existing processing class 
\emph{and} the interface class (e.g. \texttt{bbtk::AtomicBlackBox}).
In this case you have to :
\begin{enumerate}
\item make the link between the inputs and outputs of the black box 
and the interface of the inherited class
\item call the processing 
method of the inherited class in the processing method of the black box.
\end{enumerate}
\item {\bf Encapsulate} the existing processing class 
in a class inherited from 
the interface class (e.g. \texttt{bbtk::AtomicBlackBox}).
In this case you have to :
\begin{enumerate}
\item declare an instance of the processing class 
as a member of the black box, 
\item instantiate it at the right time 
(either in the constructor or in the processing method of the black box)
\item in the processing method of the black box : 
\begin{enumerate}
\item set the inputs of the member processing class with the inputs of the black box, 
\item call the processing method of the encapsulated class  
\item set the ouputs of the black box with the outputs of the encapsulated 
class.
\end{enumerate}
\end{enumerate}
\end{enumerate}

If you wish to 'blackboxify' a C-like \emph{function}, 
you do not have the choice, you can only use the second mechanism, 
namely encapsulation.

Obviously, the inheritance mechanism is more powerfull 
and - when it is possible to use it - it demands less effort 
because, as we will see, in \bbtk you can directly 
link the accessors to the input and output data of the box 
to the accessors of the inherited processing class, 
as well as the procesing method of the black box 
to the processing method of the inherited processing class, 
very much like a callback mechanism.
%\itk and \vtk classes 

% ==========================================
\subsubsection{Input and output accessors}
% ==========================================

When you encapsulate a processing class or a C function 
or when you write down a black box from scratch, 
you must access the inputs and outputs of the black box, 
in order to interface it manually with your processing method 
or simply write your processing code 
(there are other cases in which you also need to access the 
inputs and outputs, we will talk about them later). 

The only thing you must know about the \CPP code generated 
from your \xml or your \CPP macro-based description 
is that when you declare an input 
or an output of a black box then 
two \emph{accessors} for this input or output are generated : 
one to \emph{get} the value of the input or output and 
one to \emph{set} it. 
These accessors have normalized names : 

\begin{itemize} 
\item The declaration of an {\bf input} called \texttt{NAME} and 
of type \texttt{TYPE} generates the two accessors
\footnote{For the sake of simplicity, the parameters and return value are 
shown here as if they were all passed by value. 
However the actual code can use references. 
The same way, the issue of const or non const methods is eluded here. 
Different cases occur in practice.}: 
\begin{itemize} 
\item \texttt{void bbSetInput<NAME>(<TYPE>);} 
\item \texttt{<TYPE> bbGetInput<NAME>();} 
\end{itemize}
\item The declaration of an {\bf output} called \texttt{NAME} and  
of type \texttt{TYPE} generates the two accessors:
\begin{itemize} 
\item \texttt{void bbSetOutput<NAME>(<TYPE>);} 
\item \texttt{<TYPE> bbGetOutput<NAME>();} 
\end{itemize}
\end{itemize}

For example, declaring an input called \texttt{Image} 
would generate the two accessors \texttt{bbSetInputImage} and 
\texttt{bbGetInputImage}. 

Note that:
\begin{itemize}
\item All \bbtk methods are prefixed by \texttt{bb} 
to avoid conflicts with potential inherited methods. 
\item An input and an output can have the same name (e.g. 'Image').
No conflict between accessors occur (e.g. 
four distinct accessors are created : 
\texttt{bbSetInputImage}, 
\texttt{bbGetInputImage}, 
\texttt{bbSetOutputImage} and 
\texttt{bbGetOutputImage}).
\end{itemize}


% ==========================================
\subsection{Generate the black box skeleton}
% ==========================================

The command line application \bbCreateBlackBox 
allows to create a skeleton \CPP or \xml files for a new black box. 
It has a rather complex usage, 
we recommand you use the graphical interface to it 
which is accessible with \bbStudio menu \texttt{Tools $>$ Create black box}.
The interface looks like in fig. \ref{bbCreateBlackBox}.

\begin{figure}[!ht]
\caption{\label{bbCreateBlackBox}Create Black Box interface}
\begin{center}
\includegraphics[width=0.6\textwidth]{bbCreateBackBox.png}
\end{center}
\end{figure}

You will have to give :
\begin{enumerate}
  \item The {\bf name} of the box
  \item The {\bf package} to which the box belongs (can we do it automatically ? LG : think about it) 
  \item The {\bf author}(s) of the box
  \item A {\bf description} of the box

 \item Its {\bf type}, either 
   \begin{enumerate} 
     \item  Basic (inherits \texttt{AtomicBlackBox}, no particular Input/Output)
     \item  Widget (inherits \texttt{WxBlackBox}, has output 'Widget' of type 'wxWindow*')
     \item VTK PolyDataAlgorithm (inherits \texttt{AtomicBlackBox} and a vtkPolyDataAlgorithm, has standard vtk I/O)
     \item VTK ImageAlgorithm (inherits \texttt{AtomicBlackBox} and a vtkImageAlgorithm, has standard vtk I/O)

   \end{enumerate}
   
  \item The output format of the file, either a C++ file or an XML file.
\end{enumerate}

% ==========================================
\subsection{\texttt{XML} description of a box}
% ==========================================

% ==========================================
\subsubsection{General \texttt{xml} tags}
% ==========================================

Let us examine the \texttt{xml} file 
describing the \texttt{Add} box of the \texttt{std} package :

\begin{file}{\texttt{packages/std/src/bbAdd.xml}}
\small
\begin{verbatim}
<?xml version="1.0" encoding="iso-8859-1"?>

<blackbox name="Add">

  <author>laurent.guigues@creatis.insa-lyon.fr </author>
  <description>Adds its inputs                 </description>
  <category>math                               </category>

  <input name="In1"  type="double" description="First number to add"/>
  <input name="In2"  type="double" description="Second number to add"/>
  <output name="Out" type="double" description="Result"/>

  <process><PRE>
    bbSetOutputOut( bbGetInputIn1() + bbGetInputIn2() );
  </PRE></process>
  
  <constructor><PRE>
    bbSetInputIn1(0);
    bbSetInputIn2(0);
    bbSetOutputOut(0);
  </PRE></constructor>    

</blackbox>
\end{verbatim}
\end{file}

The tags and their role are easily understandable.

As the box is not a widget, we inherit implicitely from 
\texttt{bbtk::AtomicBlackBox} (the default).

The only part of the file which needs a bit of explaination is 
the body of the \texttt{process} tag, which describes the 
actual code to execute in the box. 
This code must be enclosed in a \texttt{<PRE></PRE>} tag 
to tell the \xml parser not to interpret it as \xml instructions. 
This is necessary to be able to use any symbol, 
like the \texttt{<} and \texttt{>} which have a 
special meaning in \xml. 
In the case of the \texttt{Add} box, the process code 
is very simple : remember that 
\texttt{bbGetInputIn1()} is the 
accessor to the input \texttt{In1} declared above and 
\texttt{bbGetInputIn2()} is the 
accessor to the input \texttt{In2};  
the code simply adds the values of the two inputs 
and sets the output \texttt{Out} with the resulting value.

To describe your own black boxes in \xml code, 
you must modify the xml file generated by \bbCreateBlackBox : 

\begin{enumerate}
  \item Complete the description and author tags if you feel like.
  \item Add the \texttt{\#include} directives to be put in the generated \texttt{.h} file
  \item Create your inputs and outputs
  \item Fill in the process tag
  \item Fill in the constructor tag
  \item Fill in the copyconstructor tag
  \item Fill in the destructor tag
\end{enumerate}

% ==========================================
\subsubsection{Writting new widget boxes in \xml}
% ==========================================
See the example \texttt{packages/wx/src/bbwxOutputText.xml}

\begin{file}{\texttt{packages/wx/src/bbwxOutputText.xml}}
\small
\begin{verbatim}
<blackbox name="OutputText" widget>

  <author>laurent.guigues at creatis.insa-lyon.fr</author>
  <description>Text zone to be inserted into a window (wxStaticText)</description>
  <category></category>

  <input name="Title" type="std::string" description="Title prepended to the text"/>
  <input name="In" type="std::string" description="Text"/>

  <createwidget><PRE>
   bbSetOutputWidget( new wxStaticText ( bbGetWxParent() , -1 , _T("") ) );
   Process();
  </PRE></createwidget>
 
  <process><PRE>
   std::string msg;
    if (bbGetInputTitle()!="")
      {
        msg = bbGetInputTitle()+": " + bbGetInputIn();
      }  
    else 
      {
        msg = bbGetInputIn();
      }
   ((wxStaticText*)bbGetOutputWidget())->SetLabel( bbtk::std2wx( msg ) ); 
  </PRE></process>
  
  <constructor><PRE> 
    bbSetInputIn("");
    bbSetInputTitle("");
  </PRE></constructor>    


</blackbox>
\end{verbatim}
\end{file}

Explainations:
\begin{itemize}
\item The attribute \texttt{widget} of the \texttt{blackbox} tag instructs 
\bbfy that the box inherits from \texttt{bbtk::WxBlackBox}.
\item An output called \texttt{'Widget'} of type \texttt{wxWindow*} is 
automatically declared (you do not have to do it).
\item The tag \texttt{createwidget} provides the body of the method which creates the widget. At the end of this method the output \texttt{'Widget'} must 
have been set with the newly created \texttt{wxWindow}. 
Here we create a new \texttt{wxStaticText}.
The parent of the widget to create MUST BE the one provided by the method 
\texttt{bbGetWxParent()} which returns a \texttt{wxWindow*}. 
To update the static text after creation we simply call the \texttt{Process} 
method.
\item The body of the \texttt{process} method simply concatenates the 
input \texttt{'Title'} (if non empty) and the input \texttt{'In'} and 
updates the \texttt{wxStaticText}. 
Remark that to get it, we use the \texttt{bbGetOutputWidget()} method 
which returns a \texttt{wxWindow*} which we cast into a 
\texttt{wxStaticText*} to use its specific method \texttt{SetLabel}.
\end{itemize}

More complex examples can be found in the \texttt{package/wx/src} folder.

% ==========================================
\subsubsection{Specific \texttt{xml} tags for \texttt{vtkImageAlgorithm} classes bbfication by inheritance}
% ==========================================
If you wish to bbfy a \vtk object which is a \texttt{vtkImageAlgorithm} 
(such as \texttt{vtkImageGaussianSmooth}, \texttt{ImageAnisotropicDiffusion3D},
...) we recommand you do it in \xml (you can have a look at the examples 
in the \vtk core package 'src' folder). 
The bbfication mechanism is inheritance.

You have to add the attribute \texttt{type="VTK\_ImageAlgorithm"} 
to the \texttt{blackbox} tag :
\begin{verbatim}
<blackbox name="..." type="VTK_ImageAlgorithm">
\end{verbatim}

You have to had an include tag which includes the vtk parent header, such as :
\begin{verbatim}
<include> vtkImageAnisotropicDiffusion3D.h </include> 
\end{verbatim}

You have to add the tag \texttt{vtkparent} which gives the \vtk parent of the box, e.g.:
\begin{verbatim}
<vtkparent> vtkImageAnisotropicDiffusion3D </vtkparent>
\end{verbatim}

The \vtk algorithm input/ouput are wrapped directly using the 
\texttt{special} attributes of the input and output tags. 
A typical example is :
\begin{verbatim}
<input name="In"   type="vtkImageData*" special="vtk input" 
       description="Input image"/>
<output name="Out"  type="vtkImageData*" special="vtk output"    
        description="Output image"/>
\end{verbatim}
The attribute \texttt{special="vtk input"} of the input 'In' definition 
directly connects it to the input of the vtk object the box inherits. 
No additional code is needed, the vtk object will directly receive 
the value of this input. 
The same mechanism hold for the output.

The parameters of the vtk object which are declared using 
\texttt{vtkSetMacro} and \texttt{vtkGetMacro} can also be directly 
wrapped using the attribute \texttt{special="vtk parameter"} of the input tag,
e.g. :
\begin{verbatim}
<input  name="DiffusionThreshold"  type="double" special="vtk parameter" 
        description="Difference threshold that stops diffusion"/>
\end{verbatim}
The attribute \texttt{special="vtk parameter"} 
of the input called \texttt{DiffusionThreshold} instructs \bbfy to 
directly call the \texttt{SetDiffusionThreshold} and 
\texttt{GetDiffusionThreshold} 
methods of the vtk parent when needed. 

{\bf NOTE :} 
For this mechanism to work, 
the name of the \bbtk input MUST be the same than the name 
of the \vtk parent parameter. 

No \texttt{process} method has to be given, 
\bbfy generates a process body for you, which simply calls the 
\texttt{Update()} method of the vtk parent.

{\bf NOTE :}
you can write your own \texttt{process} code which will overload 
the default. Don't forget to call Update(). 
See \texttt{packages/vtk/src/bbvtkConeSource.xml} for an example.

% ==========================================
\subsubsection{Specific \texttt{xml} tags for \texttt{vtkPolyDataAlgorithm} classes bbfication by inheritance}
% ==========================================
If you wish to bbfy a \vtk object which is a \texttt{vtkPolyDataAlgorithm} 
(such as \texttt{vtkConeSource}, ...) 
we recommand you do it in \xml (you can have a look at the examples 
in the \vtk core package 'src' folder). 
The bbfication mechanism is inheritance.

You must use the same \xml tags and attributes than for wrapping a 
\texttt{vtkImageAlgorithm} (see above) : 

\begin{verbatim}
<blackbox name="..." type="VTK_PolyDataAlgorithm">

<vtkparent>the vtk Polydata class it inherits from</vtkparent>
<input  name="..."  type="vtkPolyData*" special="vtk input"    
        description="..."/>
<output name="..."  type="vtkPolyData*" special="vtk output"    
        description="..."/>
<input  name="..."  type="double"       special="vtk parameter" 
        description="..."/>

\end{verbatim}

% ==========================================
\subsubsection{Specific \texttt{xml} tags for \texttt{itk::ImageToImageFilter} classes bbfication by inheritance}
% ==========================================

to be written...

\newpage

% ==========================================
\subsubsection{\bbfy \texttt{xml} tags reference}
% ==========================================

 See tables \ref{xml_tags}, \ref{xml_tags2}
% ==========================================
\begin{table}[!ht]
\caption{\label{xml_tags}
\bbfy \texttt{xml} tags reference (part 1)}
\small
\begin{tabular}{|lcllm{6cm}|}
\hline
Tag & Attributes & Condition & Multiplicity & Description
 \\ \hline

\texttt{<blackbox>} & \texttt{name} & - & 1 & The name of the box \\ \hline
                & \texttt{type} & - & 1 & The type of the box. In: 
        \{\texttt{standard} (default), 
\texttt{ITK\_ImageToImageFilter},
\texttt{VTK\_ImageAlgorithm},
\texttt{VTK\_PolyDataAlgorithm}\} \\\hline
& \texttt{generic} & a) & 0-1 & 
Generate the generic filter (see text)\\ \hline 
& \texttt{widget} & - & 1 & 
If present then the box inherits from \texttt{WxBlackBox} 
(\texttt{AtomicBlackBox} if absent)
\\ \hline 
\texttt{<description>} & - & - & 0-n &  The description of the box. Multiple occurrence are concatenated \\\hline 
\texttt{<author>} & - & - & 0-n &  The author of the box. Multiple occurrence are concatenated \\\hline 
\texttt{<category>} & - & - & 0-1 &  The box category (if more than one, they are separated with commas) see Tab \ref{categories}\\\hline 
\texttt{<namespace>} & - & - & 0-1 &  The namespace of the box. 
Use \texttt{bbPACKAGE}, where \texttt{PACKAGE} is the name of the package\\\hline 
\texttt{<include>} & - & - & 0-n & Additionnal file to include 
(generates : \texttt{\#include 'value'})\\\hline 

\texttt{<template>} & - & - & 0-n &  Template parameter of the box. The template parameter list is generated in the order of appearance of the tag. \\\hline 

\texttt{<itkparent>} &  - & a) &  1 & The parent itk class (with namespace) \\\hline

\texttt{<vtkparent>} &  - & b) &  1 & The parent vtk class \\\hline

\texttt{<input>} & \texttt{name} & - & 1 &  The name of the input \\\hline 
         & \texttt{type} & - & 1 &  The type of the input \\\hline 
         & \texttt{special} & - & 0-1 & In: \{\texttt{'itk input', 
'vtk input', 'itk parameter', 'vtk parameter'}\} (see below).\\\hline 
         & \texttt{generic\_type} & c) & 0-1 & The ``generic'' type of the input (see text). \\\hline 


 \end{tabular}
 \end{table}
\begin{table}[!ht]
\caption{\label{xml_tags2}
\bbfy \texttt{xml} tags reference (part 2)}
\small
\begin{tabular}{|lcllm{6cm}|}
\hline
Tag & Attributes & Condition & Multiplicity & Description
 \\ \hline
 \texttt{<output>} & \texttt{name} & - & 1 &  The name of the output \\\hline 
         & \texttt{type} & - & 1 &  The type of the output \\\hline 
         & \texttt{special} & - & 0-1 & In: \{\texttt{'itk output', 
'vtk output'}\} (see below).\\\hline
         & \texttt{generic\_type} & c) & 0-1 & The ``generic'' type  of the output (see text).\\\hline  
         & \texttt{nature} & c) & 0-1 & The ``nature'' of the output (used for automatic GUI generation).\\\hline 
\texttt{<process>} & - & - & 0-1 & The code of the processing method of the box. Must be put between clear tags : \texttt{<PRE></PRE>} \\\hline 
\texttt{<createwidget>} & - & d) & 0-1 & The code of the widget creation 
method of the box. Must be put between clear tags : \texttt{<PRE></PRE>} 
\\\hline 
\texttt{<constructor>} & - & - & 0-1 & The code of the user Constructor of the box (may contains default initialisations). Must be put between clear tags : \texttt{<PRE></PRE>} \\\hline 
\texttt{<copyconstructor>} & - & - & 0-1 & The code of the user Copy Constructor of the box . Must be put between clear tags : \texttt{<PRE></PRE>} \\\hline
\texttt{<destructor>} & - & - & 0-1 & The code of the user Destructor of the box. Must be put between clear tags : \texttt{<PRE></PRE>} \\\hline
 \end{tabular}
 \end{table}
 
 \newpage
 
% ==========================================
\begin{table}[!ht]
\caption{\label{xml_tags-conditions}
\bbfy \texttt{xml} tags conditions}
\small
\begin{tabular}{|ll|}
\hline
a) & \texttt{<blackbox type == 'ITK\_ImageToImageFilter'>} \\ \hline
b) & \texttt{<blackbox type == 'VTK\_ImageAlgorithm' or 'VTK\_PolyDataAlgorithm'>} \\ \hline
c) & \texttt{<blackbox type == 'ITK\_ImageToImageFilter'>} and 
     \texttt{<blackbox generic>} is present. \\ \hline
d) & \texttt{<blackbox widget>} is present \\ \hline
\end{tabular}
\end{table}

%\begin{table}[!ht]
%\caption{\label{basic_parent}}
%\bbfy \texttt{Basic box parent}
%\small
%\begin{tabular}{|ll|}
%\hline
%\texttt{bbtk::WxBlackBox}b) & If the blackbox associated to
%a \texttt{wxWindow} and is be able to return a pointer to it.... \\ \hline
%\texttt{bbtk::AtomicBlackBox} & Any other blackbox that doesn't return a pointer to a \texttt{wxWindow}%
%\end{tabular}
%\end{table}




% ==========================================
\begin{table}[!ht]
\caption{\label{categories} \texttt{Black Box} categories}
\small
\begin{tabular}{|p{4cm}p{8cm}|}
\hline
 \texttt{Category name}     & : Meaning                                          \\ \hline 
& \\ \hline
 \texttt{adaptor}        & : Adaptor box                                      \\ \hline
 \texttt{application}    & : Final application, end user intended             \\ \hline
 \texttt{atomic box}     & : System category.
               Automatically assigned to Atomic Black Boxes (c++ defined)     \\ \hline
 \texttt{complex box}    & : System category.
               Automatically assigned to Complex Black Boxes (script defined) \\ \hline  
 \texttt{command line}   & : Script which defines a command line application (no embedded GUI, but command line imput parameters) \\ \hline
 \texttt{demo}           & : Demonstration                             \\ \hline
 %\texttt{devel}          & : Developer tool (bbCreatePackage.bbs, ...) \\ \hline
 \texttt{dicom}          & : DICOM aware box \\ \hline 
 \texttt{example}        & : Example script showing a box use-case      \\ \hline
 \texttt{filter}         & : Filtering box                       \\ \hline
 \texttt{image}          & : Image processing related box               \\ \hline
% \texttt{interaction}    & :                                            \\ \hline
 \texttt{math}           & : Mathematical operations\\ \hline
 \texttt{mesh}           & : Mesh processing related box \\ \hline
 \texttt{misc}           & : A box that cannot be put in other category ! \\ \hline
 \texttt{read/write}     & : Box that read or write data from or to disk  \\ \hline
 \texttt{viewer}         & : Box which displays some data \\ \hline
 \texttt{widget}         & : Piece of graphical interface  \\ \hline 
 
 \texttt{3D object creator} & : Sophisticated 3D widget  \\ \hline  
 \texttt{toolsbbtk}         & : \bbtk development tools (GUICreatePackage, GUICreateBlackBox,...)   \\ \hline  
\end{tabular}
\end{table}


% ==========================================
\begin{table}[!ht]
\caption{\label{kinds}\texttt{Black box} kinds}
\small
\begin{tabular}{|p{4cm}p{8cm}|}
\hline
 \texttt{Kind}     &  Use as :     \\ \hline & \\ \hline
 \texttt{ADAPTOR} & \\ \hline
 \texttt{DEFAULT\_ADAPTOR} & \\ \hline 
 \texttt{WIDGET\_ADAPTOR} & \\ \hline 
 \texttt{DEFAULT\_WIDGET\_ADAPTOR} & \\ \hline
 \texttt{GUI} & \\ \hline 
 \texttt{DEFAULT\_GUI} & \\ \hline 
 \texttt{ALL} & If kind='ALL' then sets the level for all kinds\\ \hline  
\end{tabular}
\end{table}


% ==========================================
\begin{table}[!ht]
\caption{\label{nature}Input/output \texttt{natures}}
\small
\begin{tabular}{|ll|}
\hline
 \texttt{Nature}     &   : Associated \texttt{DEFAULT\_GUI} box   \\ \hline 
& \\ \hline

 \texttt{'file name'} & \texttt{wx::FileSelector}\\ \hline
 \texttt{'directory name'} & \texttt{wx::DirectorySelector}\\ \hline 
% \texttt{'file extension'} & \\ \hline  
 \texttt{'colour'} & \texttt{wx::ColourSelector}\\ \hline 
% \texttt{pixel type} & \\ \hline 
% \texttt{image dimension} & \\ \hline
% \texttt{image index} & \\ \hline 
% \texttt{image size} & \\ \hline 
% \texttt{voxel size} & \\ \hline  
\end{tabular}
\end{table}

.\\
.\\
.\\
.\\
.\\


\newpage 


% ==========================================
\subsection{\CPP description of a box}
% ==========================================

Almost everything is performed using macros.

For a quick start, the best you have to do is to run \texttt{bbStudio}, then in the menu \texttt{Tools}, choose the item
 \texttt{Create black box}, click on \texttt{C++}, and have a look to the generated files, or have a look at the source files of \bbtk core packages.
 
% ==========================================
\subsubsection{Black box basic header file (.h)}
% ========================================== 

Let's have a look at the file \texttt{packages/std/bbstdMakeFileName.h}

\begin{file}{\texttt{packages/std/bbstdMakeFileName.h}}
\small
\begin{verbatim}
#ifndef __bbstdMakeFileName_h_INCLUDED__
#define __bbstdMakeFileName_h_INCLUDED__

#include "bbtkAtomicBlackBox.h"

namespace bbstd
{
  class MakeFileName : public bbtk::AtomicBlackBox
  {
    BBTK_BLACK_BOX_INTERFACE(MakeFileName,bbtk::AtomicBlackBox);
    BBTK_DECLARE_INPUT(Directory, std::string);
    BBTK_DECLARE_INPUT(File,      std::string);
    BBTK_DECLARE_INPUT(Extent,    std::string);
    BBTK_DECLARE_OUTPUT(Out,      std::string);
    BBTK_PROCESS(DoProcess);
    void DoProcess();
  protected:
    virtual void bbUserConstructor();
  };

  BBTK_BEGIN_DESCRIBE_BLACK_BOX(MakeFileName,bbtk::AtomicBlackBox);
  BBTK_NAME("MakeFileName");
  BBTK_AUTHOR("jpr@creatis.insa-lyon.fr");
  BBTK_CATEGORY("misc");
  BBTK_DESCRIPTION("Makes a kosher file name");
  BBTK_INPUT(MakeFileName,Directory,"Directory Name",std::string,
             "directory name");
  BBTK_INPUT(MakeFileName,File,     "File Name",     std::string,
             "file name");
  BBTK_INPUT(MakeFileName,Extent,   "Extention",     std::string,
             "file extension");
  
  BBTK_OUTPUT(MakeFileName,Out,"Full File Name",std::string,"file name");
  BBTK_END_DESCRIBE_BLACK_BOX(MakeFileName);

}
// EO namespace bbstd

#endif //  __bbstdMakeFileName_h_INCLUDED__
\end{verbatim}
\end{file}

It includes \texttt{bbtkAtomicBlackBox.h}.
The box class is \texttt{MakeFileName}.
It inherits \texttt{bbtk::AtomicBlackBox}.
It is in the \texttt{bbstd} namespace : 
each box of a given package, say PACK, must be inserted into 
the namespace \texttt{bbPACK}.

The macro \texttt{BBTK\_BLACK\_BOX\_INTERFACE} 
declares the interface of the class : constructor, destructor,
standard methods (e.g. New), etc. 
The following macros then declare inputs and outputs of the box, 
with their types.
The macro \texttt{BBTK\_PROCESS} then declares which method to call 
when processing the box (the process callback).
The callback itself is declared just below.

The line \texttt{virtual void bbUserConstructor();} then 
overloads the virtual method \texttt{bbUserConstructor} 
which is used to perform specific things at construction time.
You can also overload \texttt{bbUserCopyConstructor} 
and \texttt{bbUserDestructor} with the same signature.
The black box interface macros are summarized in table 
\ref{CPPInterfaceBasicMacros}.

% ==========================================
\begin{table}[!ht]
\caption{\label{CPPInterfaceBasicMacros}Black box interface \CPP macros}
\begin{tabular}{p{\textwidth}}\hline
    \\ \small \texttt{BBTK\_BLACK\_BOX\_INTERFACE(BOX\_NAME,BBTK\_PARENT)} :
    Yes, we know the \bbtk parent is redundant with the inheritance list... That's why we allow you to describe your class in \xml format!
     \\ \small \texttt{BBTK\_VTK\_BLACK\_BOX\_INTERFACE(CLASS,BBTK\_PARENT,VTK\_PARENT) } : Black box interface for \vtk object inherited boxes
        \dots
    \\ \small \texttt{BBTK\_ITK\_BLACK\_BOX\_INTERFACE(CLASS,BBTK\_PARENT,ITK\_PARENT) } : Black box interface for \itk object inherited boxes
        \dots
    \\ \small \texttt{BBTK\_DECLARE\_INPUT (NAME,TYPE) } : Declares an input of the box, with \texttt{NAME} : the input name (as it will appear to the users of your black box) and \texttt{TYPE} : \CPP type of the input (e.g. double, std::string, vtkImageData*, ...).
  \\ \small \texttt{BBTK\_DECLARE\_INHERITED\_INPUT(NAME,TYPE,GETMETHOD,SETMETHOD)} : Declares an input of the box which wraps the \texttt{GETMETHOD / SETMETHOD} accessors
    \\ \small \texttt{BBTK\_DECLARE\_VTK\_INPUT(NAME,TYPE)} :
         Declares a vtk object-inherited input
   \\ \small \texttt{BBTK\_DECLARE\_VTK\_IMAGE\_ALGORITHM\_INPUT(NAME,TYPE)} :    Declares a vtkImageAlgorithm-inherited input 
    \\ \small \texttt{BBTK\_DECLARE\_VTK\_POLY\_DATA\_ALGORITHM\_INPUT(NAME,TYPE)} : Declares a vtkPolyDataAlgorithm-inherited input  
    \\ \small \texttt{BBTK\_DECLARE\_ITK\_INPUT (NAME,TYPE)} :
         Declares a itk object-inherited input
  \\ \small \texttt{BBTK\_DECLARE\_OUTPUT (NAME,TYPE) } :
        Declares an output of the box 
  \\ \small \texttt{BBTK\_DECLARE\_INHERITED\_OUTPUT(NAME,TYPE,GETMETHOD,SETMETHOD)} :
    Declares an output of the box which wraps the \texttt{GETMETHOD / SETMETHOD} accessors
    \\ \small \texttt{BBTK\_DECLARE\_VTK\_OUTPUT(NAME,TYPE)} :
        Declares a vtk object-inherited output    
     \\ \small \texttt{BBTK\_DECLARE\_ITK\_OUTPUT(NAME,TYPE)} :
         Declares a itk object-inherited output
   \\ \small \texttt{BBTK\_DECLARE\_VTK\_PARAM(VTK\_PARENT,NAME,TYPE)} :
 Declares an input corresponding to an inherited vtk parameter 
     (you know, the ones that are declared by vtkSetMacro/vtkGetMacro). Its name must be the same than the vtk parameter name.  
    \\ \small \texttt{BBTK\_DECLARE\_ITK\_PARAM(NAME,TYPE)} :
 Declares an input corresponding to an inherited itk parameter 
    \\ \small \texttt{BBTK\_PROCESS(METHOD\_NAME)} :
        Defines the method to call when the box is processed. 
    \\ \small \texttt{BBTK\_VTK\_PROCESS} :                                                     Defines AND implements the default processing method for vtk 
        inherited black boxes (calls \texttt{vtkParent::Update})
  \\ \small \texttt{BBTK\_ITK\_PROCESS} :                                                       Defines AND implements the default processing method for itk 
        inherited black boxes (calls \texttt{itkParent::Update})
\\ 
\hline\end{tabular}

\end{table}
%================================================

After the black box class declaration 
then comes a zone in which you describe your black box, 
between the macros \texttt{BBTK\_BEGIN\_DESCRIBE\_BLACK\_BOX} 
and \\ \texttt{BBTK\_END\_DESCRIBE\_BLACK\_BOX}.

The macro \texttt{BBTK\_BEGIN\_DESCRIBE\_BLACK\_BOX} 
actually starts the declaration of another class, 
called \texttt{\textless BOXNAME \textgreater Descriptor} 
(in our case \texttt{MakeFileNameDescriptor}).
The descriptor of a black box :
\begin{itemize}
\item has only one instance, which is stored in the package
\item provides information about the box type (author, description, ...) 
which is used for documentation.
\item provides information about the box I/Os, mainly their types
(uses RTTI : \texttt{std::type\_info} ).
\item is responsible for creating new instances of the box it describes.
\end{itemize}

As you can see, 
the macros which are between \texttt{BBTK\_BEGIN\_DESCRIBE\_BLACK\_BOX} 
and \texttt{BBTK\_END\_DESCRIBE\_BLACK\_BOX} 
provide the box name (the string), 
its authors, description, category, 
the descriptions of its inputs and outputs.
Black box descriptor related 
are described in table \ref{CPPDescriptorBasicMacros}.

% ==========================================
\begin{table}[!ht]
\caption{\label{CPPDescriptorBasicMacros}Black box descriptor \CPP macros}
\begin{tabular}{p{\textwidth}}\hline
    \\ \small \texttt{BBTK\_BEGIN\_DESCRIBE\_BLACK\_BOX(BOX\_NAME,BBTK\_PARENT) }  : 
    Yes, we know it's redundant with public inheritance ... That's why we allow you to describe your class in xml format! 
    All the following items will be used in the Help interface; describe them carefully (i.e. in a Human understandable way!).
  \\ \small \texttt{BBTK\_ADAPTOR} : Declares that the box is an adaptor
  \\ \small \texttt{BBTK\_DEFAULT\_ADAPTOR} : Declares that the box is the default adaptor for its I/O types
   \\ \small \texttt{BBTK\_NAME(STRING)} : The name of your box 
    \\ \small \texttt{BBTK\_AUTHOR(STRING)} : The author(s) (better you put e-mail adresses)
    \\ \small \texttt{BBTK\_DESCRIPTION(STRING)} : Brief description of what does the box
    \\ \small \texttt{BBTK\_CATEGORY(STRING)} : Box categories, semicolon separated  (see table \ref{categories})
    \\ \small \texttt{BBTK\_INPUT(BOX\_NAME,INPUT\_NAME,DESCRIPTION,CPP\_TYPE,INPUT\_NATURE)} 
       \begin{itemize}
         \item \texttt{BOX\_NAME} : The current black box name.
         \item \texttt{INPUT\_NAME} : The input name
         \item \texttt{DESCRIPTION} (string) : A brief description of what the parameter is used for.
         \item \texttt{CPP\_TYPE} : The \CPP type of the input (e.g. double, std::string, vtkImageData*, ...) 
         \item \texttt{INPUT\_NATURE} : The 'nature' of the parameter (see table \ref{nature}) if you wish your box may be used by automatic GUI generator.
         Supply an empty string ("") if you don't care.          
       \end{itemize}
    \\ \small\texttt{BBTK\_OUTPUT(BOX\_NAME,OUTPUT\_NAME,DESCRIPTION,CPP\_TYPE)} : The same
     \\ \small \texttt{BBTK\_END\_DESCRIBE\_BLACK\_BOX(BOX\_NAME)} 
 \\ \hline\end{tabular}
\end{table}

% ==========================================
\subsubsection{Black box basic implementation file (.cxx)}
% ========================================== 

Now let's have a look at the file \texttt{packages/std/bbstdMakeFileName.cxx}

\begin{file}{\texttt{packages/std/bbstdMakeFileName.cxx}}
\small
\begin{verbatim}
#include "bbstdMakeFileName.h"
#include "bbstdPackage.h"

namespace bbstd
{

  BBTK_ADD_BLACK_BOX_TO_PACKAGE(std,MakeFileName);
  BBTK_BLACK_BOX_IMPLEMENTATION(MakeFileName,bbtk::AtomicBlackBox);
  
  void MakeFileName::bbUserConstructor()
  {
    bbSetInputDirectory("");
    bbSetInputFile("");
    bbSetInputExtent("");
  }
  
  void MakeFileName::DoProcess()
  {
    ...
  }
}
// EO namespace bbstd
\end{verbatim}
\end{file}

The first line includes the header file.
The second one includes the \texttt{std} package header file.
This file is automatically generated during cmake configuration :
for a package named \texttt{\textless PACK \textgreater}, \cmake
creates the files \texttt{bb\textless PACK \textgreater Package.h} 
and \texttt{bb\textless PACK \textgreater Package.cxx}.
The header is to be included in any box implementation file and 
the second one is compiled in the package library.

The macro \texttt{BBTK\_ADD\_BLACK\_BOX\_TO\_PACKAGE} 
then registers the box \texttt{MakeFileName} into the package \texttt{std}.

The macro \texttt{BBTK\_BLACK\_BOX\_IMPLEMENTATION} is the 
mirror macro of the macro \texttt{BBTK\_BLACK\_BOX\_INTERFACE} that 
was used in the header : it implements the methods declared in the header.

We then need to write the body of \texttt{bbUserConstrutor} 
and of the processing callback (here \texttt{DoProcess}).

That's all we need for a 'basic' black box.
The implementation related macros are summarized in table \ref{CPPImplementationBasicMacros}.

% ==========================================
\begin{table}[!ht]
\caption{\label{CPPImplementationBasicMacros}Black box implementation \CPP macros}
\begin{tabular}{p{\textwidth}}\hline
    \\ \small \texttt{BBTK\_ADD\_BLACK\_BOX\_TO\_PACKAGE(PACKAGE\_NAME,BOX\_NAME)}
   \\ \small  \texttt{BBTK\_BLACK\_BOX\_IMPLEMENTATION(BOX\_NAME,BBTK\_PARENT)}
\\ \hline
\end{tabular}
\end{table}
 
% ==========================================
\subsubsection{Widget black boxes \CPP macros}
% ==========================================

See the example of \texttt{package/wx/src/bbwxLayoutLine.h\textbar cxx}.
The only differences with a non-widget black box are :
\begin{itemize}
\item The header must include \texttt{bbtkWxBlackBox.h} and \\ 
the class must inherit \texttt{bbtk::WxBlackBox}.
\item The black box interface must declare the widget creation callback 
with the macro \texttt{BBTK\_CREATE\_WIDGET(CALLBACK)}. 
The callback must be declared in the interface and implemented. 
\item You can overload the method \texttt{void bbUserOnShow()} which 
is called just after the \texttt{wxWindow} has been shown, e.g. 
to refresh its content. Note that \texttt{Layout} widget \emph{MUST}
overload this method and call \texttt{bbUserOnShowWidget(INPUT\_NAME)} 
for all inputs which correspond to an 'embedded' window
(the 'Widget1' ... 'WidgetN' inputs, 
see \texttt{package/wx/src/bbwxLayoutLine.cxx})
\end{itemize}

% ==========================================
\subsubsection{VTK black boxes \CPP macros}
% ==========================================

See the example of \texttt{package/wx/src/bbvtkMarchingCubes.h\textbar cxx}.
The macros are summarized in table \ref{CPPInterfaceBasicMacros}.

% ==========================================
\subsubsection{Template black boxes \CPP macros}
% ==========================================

You can write down black box classes \emph{templates}. 
However, only \emph{actual} classes, that is instanciated templates, 
can be inserted into a package.

The files \texttt{package/std/src/bbstdStringTo.h\textbar cxx} 
provide an example of a class template with one template parameter. 

The files \texttt{package/std/src/bbstdCast.h\textbar cxx} 
provide an example of a class template with two template parameters. 

Class templates related macros are summarized in table \ref{CPPTemplateMacros}.
% ==========================================
\begin{table}[!ht]
\caption{\label{CPPTemplateMacros}Black box templates-related \CPP macros}
\begin{tabular}{p{\textwidth}}\hline
% \begin{itemize}
    \\  \small\texttt{BBTK\_TEMPLATE\_BLACK\_BOX\_INTERFACE(BOX\_NAME,BBTK\_PARENT, TEMPLATE\_PARAMETER)}
    \\  \small\texttt{BBTK\_TEMPLATE2\_BLACK\_BOX\_INTERFACE(BOX\_NAME,BBTK\_PARENT, TEMPLATE\_PARAMETER\_1, TEMPLATE\_PARAMETER\_2)}
    \\  \small\texttt{BBTK\_BEGIN\_DESCRIBE\_TEMPLATE\_BLACK\_BOX(BOX\_NAME,BBTK\_PARENT)} : Note that in the descriptor, the template parameter name is \texttt{T}
\\ \small\texttt{BBTK\_BEGIN\_DESCRIBE\_TEMPLATE2\_BLACK\_BOX(BOX\_NAME,BBTK\_PARENT)} : Note that in the descriptor, the template parameters names are \texttt{T1} and \texttt{T2}
    \\ \small\texttt{BBTK\_END\_DESCRIBE\_TEMPLATE\_BLACK\_BOX(BOX\_NAME)}
   \\ \small\texttt{BBTK\_END\_DESCRIBE\_TEMPLATE2\_BLACK\_BOX(BOX\_NAME)}
     \\ \small\texttt{BBTK\_TEMPLATE\_INPUT(BOX\_NAME,INPUT\_NAME,DESCRIPTION,CPP\_TYPE, INPUT\_NATURE)} : Same than for non-templates, except that the \texttt{CPP\_TYPE} can be the template parameter.
    \\ \small\texttt{BBTK\_TEMPLATE2\_INPUT(BOX\_NAME,INPUT\_NAME,DESCRIPTION,CPP\_TYPE, INPUT\_NATURE)} : Same remark
 \\\small \texttt{BBTK\_TEMPLATE\_OUTPUT(BOX\_NAME,OUTPUT\_NAME,DESCRIPTION,CPP\_TYPE)} : Same remark 
 \\ \small\texttt{BBTK\_TEMPLATE2\_OUTPUT(BOX\_NAME,OUTPUT\_NAME,DESCRIPTION,CPP\_TYPE)} : Same remark 
 \\ \small\texttt{BBTK\_BLACK\_BOX\_TEMPLATE\_IMPLEMENTATION(BOX\_NAME,BBTK\_PARENT)}
 \\ \small\texttt{BBTK\_BLACK\_BOX\_TEMPLATE2\_IMPLEMENTATION(BOX\_NAME,BBTK\_PARENT)}
 \\ \small\texttt{BBTK\_ADD\_TEMPLATE\_BLACK\_BOX\_TO\_PACKAGE(PACKAGE\_NAME,BOX\_NAME, TEMPLATE\_PARAMETER\_VALUE)} : Adds the black box template instanciated on a certain value of its template parameter to the package. You can put as many such lines with different template parameter values as you want (see e.g. \texttt{package/std/src/bbstdStringTo.cxx})
 \\ \small\texttt{BBTK\_ADD\_TEMPLATE2\_BLACK\_BOX\_TO\_PACKAGE(PACKAGE\_NAME,BOX\_NAME, TEMPLATE\_PARAMETER\_1\_VALUE, TEMPLATE\_PARAMETER\_2\_VALUE)} :
The same for two template parameters (see  e.g. \texttt{package/std/src/bbstdCast.cxx})
\\
%\end{itemize}
\\ \hline
\end{tabular}
\end{table}


{\bf IMPORTANT NOTE ON TEMPLATE BLACK BOXES NAMES:}

Two different boxes registered in a package must have two different names. 
Hence when using black box classes templates, 
one must give different names to two instanciations of the template on 
two different types. 
This is typically done with inserting the template parameter type name in the 
black box class name.
An example is provided in \texttt{package/std/src/bbstdStringTo.h} : 

\begin{verbatim}
  BBTK_BEGIN_DESCRIBE_TEMPLATE_BLACK_BOX(ToString,bbtk::AtomicBlackBox);
  BBTK_NAME(bbtk::HumanTypeName<T>()+"ToString");
   ... 
  BBTK_END_DESCRIBE_TEMPLATE_BLACK_BOX(ToString);
\end{verbatim}

To get the string corresponding to the name of a \CPP type
(here the template parameter \texttt{T})
one must use the template \bbtk function \texttt{bbtk::HumanTypeName<T>()}
\footnote{\texttt{HumanTypeName} returns a human readable type name, 
without special chars such as \texttt{::} or \textless. For example the 
human readable type name of \texttt{std::vector\textless std::string \textgreater} is \texttt{VectorOfString}. The 'inhuman' type name is given 
by the function \texttt{bbtk::TypeName<T>()}.}.
It is then concatenated to the name \texttt{ToString}.
This thus gives the name \texttt{IntToString} to the black box \texttt{ToString\textless int \textgreater}, 
\texttt{DoubleToString} to the black box \texttt{ToString\textless double \textgreater}, etc.

You can also use \texttt{bbtk::HumanTypeName<T>()} 
in the macro \texttt{BBTK\_DESCRIPTION}, like for example: 
\begin{verbatim}
  BBTK_DESCRIPTION("Converts a "+bbtk::HumanTypeName<T>()+" ("
                   +bbtk::TypeName<T>()+") into a string");
\end{verbatim}


% ==========================================
\subsubsection{ITK black boxes \CPP macros}
% ==========================================

It is a special cas of black box templates with also 
special macros for itk object inherited black boxes. 

See the example of \texttt{package/wx/src/bbitkBinaryThresholdImageFilter.h\textbar cxx}, 
the tables \ref{CPPInterfaceBasicMacros} and \ref{CPPTemplateMacros}.

Note that 
there is also a mechanism for making 
``generic'' untemplatized itk black boxes.
See the example in the file above.

% ==========================================
\end{document}