/**

\page tutorial-install-raspberry Tutorial: Installation from source for Raspberry Pi
\tableofcontents

In this tutorial you will learn how to install ViSP from source on [Raspberry Pi](http://www.raspberrypi.org/help/what-is-a-raspberry-pi)
equipped with an optional HD camera module. This tutorial was tested with a RPi 1, RPi 2 model B and RPi 4 model B.

\image html img-raspberry-pi.jpg

In a first section we give some useful instructions to start with a Raspberry PI. Then in the second section, we focus on the installation
of ViSP from source.

\note Concerning ViSP installation, we provide also other \ref tutorial.

\section install_raspberry Raspberry Pi installation

\subsection install_raspberry_setup Setting up Raspberry Pi

- There are a lot of documentation and tutorial that explain different ways to setup a Raspberry Pi. A good reference is the official
page http://www.raspberrypi.org/.

- To install Raspberry Pi OS on a SD card, go to http://www.raspberrypi.org/downloads/ and download and install
Raspberry Pi Imager to a computer with an SD card reader. Put the SD card you'll use with your Raspberry Pi into
the reader and run Raspberry Pi Imager. At the end of the process, plug your SD card in your Raspberry Pi and
finish the installation by setting your login, password, region and language.

\subsection install_raspberry_login Logging in

- The default login for Raspbian is username `pi` with the password `raspberry`.

\subsection update Update your Raspbian distribution

- If your Raspberry Pi is connected to Ethernet you can update your Raspbian distribution:
\verbatim
$ sudo apt-get update
$ sudo apt-get upgrade
\endverbatim

\subsection install_raspberry_camera Setting up a Raspberry Pi camera

- If you have a Raspberry Pi camera module see http://www.raspberrypi.org/help/camera-module-setup/. To resume, enable the camera using:
\verbatim
$ sudo raspi-config
\endverbatim
- Enter in menu "Interfacing Options" to enable the camera.
- Do a reboot
\verbatim
$ sudo reboot
\endverbatim

- Connect again and load the camera module:
\verbatim
$ sudo modprobe bcm2835-v4l2
\endverbatim

- This will add the following modules:
\verbatim
$ lsmod
Module Size Used by
bcm2835_v4l2 37611 0
videobuf2_core 30853 1 bcm2835_v4l2
v4l2_common 7792 1 bcm2835_v4l2
videodev 121362 3 bcm2835_v4l2,v4l2_common,videobuf2_core
\endverbatim

- To check if the camera is recognized and connected, run:
\verbatim
$ v4l2-ctl --list-formats
\endverbatim

- After each Raspberry Pi reboot you need to relaunch the previous modprobe command. To load bcm2835-v4l2 module during reboot,
you can edit `/etc/modules` file
\verbatim
$ sudo nano /etc/modules
\endverbatim
and add a line with the name of the module:
\verbatim
bcm2835-v4l2
\endverbatim

- To check if the camera is working you may run in a terminal:
\verbatim
$ v4l2-ctl --overlay=1 # enable viewfinder
\endverbatim
Here you should see the live camera stream. To disable camera view run
\verbatim
v4l2-ctl --overlay=0 # disable viewfinder
\endverbatim

\subsection install_raspberry_startx Start graphical user interface

- To load the graphical user interface, type `startx` and press Enter on your keyboard. This will later allow to use ViSP
vpDisplayX or vpDisplayOpenCV classes useful to display images in a X11 window.

\section install_raspberry_visp_prerequisites Install prerequisites

- First you need to install the following packages (g++, CMake, Git) that are requested to get and build ViSP:
\verbatim
$ sudo apt-get install build-essential cmake-curses-gui git subversion wget
\endverbatim

\section install_raspberry_ws Create a workspace

First create a workspace that will contain all ViSP source, build, data set and optional 3rd parties. This workspace is
here set to `$HOME/visp-ws` folder, but it could be set to any other location.

In a terminal, run:
\verbatim
$ echo "export VISP_WS=$HOME/visp-ws" >> ~/.bashrc
$ source ~/.bashrc
$ mkdir -p $VISP_WS
\endverbatim

\section install_raspberry_quick Quick ViSP installation

In this section, we give minimal instructions to build ViSP from source just to try ViSP without entering in \ref install_raspberry_advanced.

- Install a small number of recommended 3rd parties
\verbatim
$ sudo apt-get install libopencv-dev libx11-dev liblapack-dev libeigen3-dev libv4l-dev \
  libzbar-dev libpthread-stubs0-dev libjpeg-dev libpng-dev
\endverbatim

- Get ViSP source code
\verbatim
$ cd $VISP_WS
$ git clone https://github.com/lagadic/visp.git
\endverbatim

- Create a build folder and build ViSP
\verbatim
$ mkdir -p $VISP_WS/visp-build
$ cd $VISP_WS/visp-build
$ cmake ../visp
$ make -j4
\endverbatim

- Set `VISP_DIR` environment variable
\verbatim
$ echo "export VISP_DIR=$VISP_WS/visp-build" >> ~/.bashrc
$ source ~/.bashrc
\endverbatim

To have a trial, just jump to \ref install_raspberry_dataset before running some binaries that you just build or
jump to \ref install_raspberry_next. You can later come back to the \ref install_raspberry_advanced.

\section install_raspberry_advanced Advanced ViSP installation

\subsection install_raspberry_3rdparty Install 3rd parties

ViSP is interfaced with several optional 3rd party libraries.
Follow the link to see the complete list of \ref supported-third-parties.

\note ViSP can be used without any third-party since all of them are optional. But obviously in this case, as we do not want
to reinvent the wheel, some features implemented in third-party libraries will not be exploitable through ViSP.
It is therefore possible to skip in a first time this section and start directly to \ref install_raspberry_quick.
Later, if you realize that a third-party library is missing, you can still install it, go back to the build folder,
configure ViSP with CMake to detect the newly installed third-party library and build ViSP again as explained
in \ref install_raspberry_tips_new_3rdparty.

\subsubsection install_raspberry_visp_3rd_party Install recommended 3rd parties

ViSP is interfaced with several optional 3rd party libraries.
Follow the link to see the complete list of \ref supported-third-parties.
We recommend to install the following:

- OpenCV
- libX11 to be able to open a window to display images
- lapack and eigen to benefit from optimized mathematical capabilities
- libv4l to grab images from usb or analogic cameras
- libzbar to be able to detect QR codes
- pthread library

Installation of recommended 3rd parties could be performed running:
\verbatim
$ sudo apt-get install libopencv-dev libx11-dev liblapack-dev libeigen3-dev libv4l-dev \
  libzbar-dev libpthread-stubs0-dev
\endverbatim

\subsubsection install_raspberry_visp_3rd_party_other Other optional 3rd parties

We give also the way to install other 3rd party libraries to enable specific capabilities.

- libjpeg and libpng to support jpeg and png images respectively (only useful if OpenCV is not installed)
\verbatim
$ sudo apt-get install libjpeg-dev libpng-dev
\endverbatim

\subsection install_raspberry_visp_get_source Get ViSP source code

There are different ways to get ViSP source code on Raspberry Pi:

- You can download the <a href="https://visp.inria.fr/download">latest release</a> as a zip or a tarball.
Once downloaded, uncompress the file using either
\verbatim
$ tar xvzf visp-x.y.z.tar.gz -C $VISP_WS
\endverbatim
or
\verbatim
$ unzip visp-x.y.z.zip -d $VISP_WS
\endverbatim

- You can also download a <a href="https://visp.inria.fr/download#snapshot">daily snapshot</a>. Once downloaded,
uncompress the file using
\verbatim
$ tar xvzf visp-snapshot-yyyy-mm-dd.tar.gz -C $VISP_WS
\endverbatim

- Or you get the cutting-edge ViSP from <a href="https://github.com/lagadic/visp">GitHub repository</a> using
the following command
\verbatim
$ cd $VISP_WS
$ git clone https://github.com/lagadic/visp.git
\endverbatim

We suppose now that ViSP source is in the directory `$VISP_WS/visp`. The following should be adapted if you
downloaded ViSP from a zip or tarball. In that case, the source is rather in something like `$VISP_WS/visp-x.y.z`.

\subsection install_raspberry_visp_config Configure ViSP from source

These are the steps to configure ViSP from source with CMake:

- In the workspace, create first a directory named `visp-build` that will contain all the build material;
generated Makefiles, object files, output libraries and binaries.
\verbatim
$ mkdir $VISP_WS/visp-build
\endverbatim

- Enter the `visp-build` folder and configure the build:
\verbatim
$ cd $VISP_WS/visp-build
$ cmake ../visp
\endverbatim
A more versatile way to configure the build is to use `ccmake`, the CMake GUI:
\verbatim
$ ccmake ../visp
\endverbatim
The following image shows that this command allows to configure (just by pressing [c] key) the build in a more
advanced way where some options could be easily turned ON/OFF. It allows also to see which are the 3rd parties that
will be used. To generate the makefiles, just press [g] key in the ccmake gui.
\image html img-ccmake-raspberry-all.png Snapshot of the `"ccmake ../visp"` command used to configure ViSP.

\subsection install_raspberry_visp_build Build ViSP libraries

To build ViSP libraries proceed with:
\verbatim
$ cd $VISP_WS/visp-build
$ make -j4
\endverbatim

\subsection install_raspberry_visp_doc Build ViSP documentation

To build ViSP documentation, you have first to install Doxygen package:
\verbatim
$ sudo apt-get install doxygen graphviz texlive-latex-base
\endverbatim
Then you can proceed with:
\verbatim
$ cd $VISP_WS/visp-build
$ cmake ../visp
$ make -j4 visp_doc
\endverbatim
The generated documentation is then available in `$VISP_WS/visp-build/doc/html/index.html`

\note
- To speed up generating online doc, particularly around formula rendering, you can use [MatJax](https://www.mathjax.org).
To this end, install MathJax and build doc using:
\verbatim
$ npm install mathjax
$ cmake ../visp -DUSE_MATHJAX=ON
$ make -j4 visp_doc
\endverbatim
\note
- It is also possible to generate a more complete documentation that includes also all the internal classes.
This could be achieved setting CMake var `ENABLE_FULL_DOC` to `ON` like:
\verbatim
$ cmake ../visp -DENABLE_FULL_DOC=ON
$ make -j4 visp_doc
\endverbatim

\subsection install_raspberry_visp_dir Set VISP_DIR environment var

In order to ease ViSP detection by CMake when ViSP is used as a 3rd party in an external project, like the one
described in the \ref tutorial-getting-started, you may set `VISP_DIR` environment variable with the path to the
`VISPConfig.cmake` file:
\verbatim
$ echo "export VISP_DIR=$VISP_WS/visp-build" >> ~/.bashrc
$ source ~/.bashrc
\endverbatim

\section install_raspberry_dataset Install ViSP data set

Some ViSP examples and tests require a data set that contains images, video, models that is not part of ViSP
source code. This data set is available in Github (https://github.com/lagadic/visp-images) or as a release in a
separate archive named `visp-images-x.y.z.zip`. This archive could be downloaded from https://visp.inria.fr/download page.
Note that ViSP tutorials are not using ViSP data set.

We give hereafter the two ways to get this data set:

<b>1. Get data set release</b>

- Download `visp-images-3.6.0.zip` from https://visp.inria.fr/download and uncompress it in your workspace `%%VISP_WS%`:
\verbatim
$ unzip ~/Downloads/visp-images-3.6.0.zip -d $VISP_WS
\endverbatim
- We suppose now that the data are located in `$VISP_WS/visp-images-3.6.0`.
\verbatim
$ ls $VISP_WS/visp-images-3.6.0
3dmodel          README.md    ellipse     mbt        video
AprilTag         Solvay       ellipse-1   mbt-cao    warp
Bayer            calibration  endianness  mbt-depth  xml
Gaussian-filter  circle       faces       memorial
Klimt            cube         iv          mire
LICENSE.txt      dnn          line        mire-2
\endverbatim
- Once downloaded, you need to set `VISP_INPUT_IMAGE_PATH` environment variable to help ViSP examples and tests to detect
automatically the location of the requested data. In our case, this variable should be set to `$VISP_WS/visp-images-3.6.0`.
It is more convenient if this environment variables is automatically added to your bash session every time a new
shell is launched:
\verbatim
$ echo "export VISP_INPUT_IMAGE_PATH=$VISP_WS/visp-images-3.6.0" >> ~/.bashrc
$ source ~/.bashrc
\endverbatim

<b>2. Get data set from github</b>

- Use git to get the data set latest version:
\verbatim
C:\> cd $VISP_WS
C:\> git clone https://github.com/lagadic/visp-images.git
\endverbatim
- Once cloned, you need to set `VISP_INPUT_IMAGE_PATH` environment variable to help ViSP examples and tests to detect
automatically the location of the requested data. In our case, this variable should be set to `$VISP_WS%/visp-images`.
In a shell run:
\verbatim
$ echo "export VISP_INPUT_IMAGE_PATH=$VISP_WS/visp-images" >> ~/.bashrc
$ source ~/.bashrc
\endverbatim

<b>Test data set usage</b>

- From now, you can try to run ViSP examples and tests. For example you can run `displayX` example that should open
a windows with Klimt painting image and some overlay drawings:
\verbatim
$ cd $VISP_WS/visp-build
$ ./example/device/display/displayX

A click to close the windows...

A click to display a cross...
Cross position: 201, 441

A click to exit the program...
Bye
\endverbatim

\section install_raspberry_tips Tips and tricks

\subsection install_raspberry_tips_new_3rdparty How to take into account a newly installed 3rd party

Since all 3rd parties are optional you may have started to install only some of them. Imagine that you just installed
a new third-party, or that you upgraded the version of this 3rd party. The next step is to go back to the build folder,
configure ViSP with CMake to detect the newly installed third-party library and build again ViSP. This could be achieved with:
\verbatim
$ cd $VISP_WS/visp-build
$ cmake ../visp
\endverbatim

Here you can check the content of the `ViSP-third-party.txt` file and see if the newly installed 3rd party is well
detected (see \ref install_raspberry_tips_3rd_party).

Finally, you need to rebuild ViSP with:
\verbatim
$ make -j4
\endverbatim

\subsection install_raspberry_tips_install How to install ViSP

Installing ViSP is optional and not recommended, since ViSP could be used as a 3rd party without installation.
If you still want to proceed with the installation run:
\verbatim
$ cd $VISP_WS/visp-build
$ sudo make install
\endverbatim
\note The default install location is set to `/usr/local`. This location could be changed modifying `CMAKE_INSTALL_PREFIX` var:
\verbatim
$ cd $VISP_WS/visp-build
$ cmake ../visp -DCMAKE_INSTALL_PREFIX=/usr
$ make -j4
$ sudo make install
\endverbatim

\note If you proceed to ViSP installation in a system folder like `/usr` or `/usr/local` there is no need to
\ref install_raspberry_visp_dir that helps CMake to find ViSP libraries in an external project that uses ViSP as a 3rd party.
If you rather install ViSP in a non "standard" folder, let say `/my/install/folder`, you have to set `VISP_DIR`
to `/my/install/folder/lib/cmake/visp` that contains the `VISPConfig.cmake` file:
\verbatim
$ cd $VISP_WS/visp-build
$ cmake ../visp -DCMAKE_INSTALL_PREFIX=/my/install/folder
$ make -j4
$ sudo make install
$ echo "export VISP_DIR=/my/install/folder/lib/cmake/visp" >> ~/.bashrc
$ source ~/.bashrc
\endverbatim

\subsection install_raspberry_tips_uninstall How to uninstall ViSP

After ViSP installation, you can remove installed material using:
\verbatim
$ cd $VISP_WS/visp-build
$ sudo make uninstall
\endverbatim

\subsection install_raspberry_tips_modules How to build only ViSP libraries

If you want to build only ViSP modules libraries, nor the examples, tutorials and tests:
\verbatim
$ cd $VISP_WS/visp-build
$ make -j4 visp_modules
\endverbatim

\subsection install_raspberry_tips_module_once How to build a ViSP specific module

If you want to build a given module and all the dependencies:
\verbatim
$ cd $VISP_WS/visp-build
$ make -j4 visp_<module_name>
\endverbatim

For example to build the model-based tracker module named mbt, run:
\verbatim
$ cd $VISP_WS/visp-build
$ make -j4 visp_mbt
\endverbatim

\subsection install_raspberry_tips_target Which are the targets that could be run with make ?

To know which are the target available with `make`:
\verbatim
$ make help | grep visp
... visp_tests
... visp_tutorials
... visp_examples
... visp_demos
... visp_modules
... visp_clipper
... visp_apriltag
... visp_qbdevice
... visp_reflex_takktile2
... visp_pugixml
... visp_simdlib
... visp_core
... visp_gui
... visp_imgproc
... visp_io
... gen_visp_java_source
... visp_klt
... visp_me
... visp_sensor
... visp_ar
... visp_blob
... visp_robot
... visp_visual_features
... visp_vs
... visp_vision
... visp_detection
... visp_mbt
... visp_tt
... visp_tt_mi
\endverbatim

\subsection install_raspberry_tips_3rd_party Which are the 3rd party libraries that are used in ViSP ?

To see which are the optional 3rd parties that are found during the configuration stage and that will be used by ViSP
during the build you can have a look to the text file named `ViSP-third-party.txt` and located in `$VISP_WS/visp-build`.
We provide hereafter an example of a possible content of this file that contains also build info.
\verbatim
$ cat $VISP_WS/visp-build/ViSP-third-party.txt
==========================================================
General configuration information for ViSP 3.3.1

  Version control:               3.2.0-1295-g1656e6037

  Platform:
    Timestamp:                   2020-12-07T13:18:39Z
    Host:                        Linux 5.4.79-v7l+ armv7l
    CMake:                       3.13.4
    CMake generator:             Unix Makefiles
    CMake build tool:            /usr/bin/make
    Configuration:               Release

  C/C++:
    Built as dynamic libs?:      yes
    C++ Compiler:                /usr/bin/c++  (ver 8.3.0)
    C++ flags (Release):         -Wall -Wextra -fopenmp -std=c++11 -fvisibility=hidden -fPIC -O3 -DNDEBUG
    C++ flags (Debug):           -Wall -Wextra -fopenmp -std=c++11 -fvisibility=hidden -fPIC -g
    C Compiler:                  /usr/bin/cc
    C flags (Release):           -Wall -Wextra -fopenmp -std=c++11 -fvisibility=hidden -fPIC -O3 -DNDEBUG
    C flags (Debug):             -Wall -Wextra -fopenmp -std=c++11 -fvisibility=hidden -fPIC -g
    Linker flags (Release):
    Linker flags (Debug):

  ViSP modules:
    To be built:                 core gui imgproc io java_bindings_generator klt me sensor ar blob robot visual_features vs vision detection mbt tt tt_mi
    Disabled:                    -
    Disabled by dependency:      -
    Unavailable:                 java

  Python (for build):            /usr/bin/python2.7

  Java:
    ant:                         /usr/bin/ant (ver 1.10.5)
    JNI:                         NO

  Build options:
    Build deprecated:            yes
    Build with moment combine:   no

  Mathematics:
    Blas/Lapack:                 yes
    \- Use MKL:                  no
    \- Use OpenBLAS:             no
    \- Use Atlas:                no
    \- Use Netlib:               yes (ver 3.8.0)
    \- Use GSL:                  no
    \- Use Lapack (built-in):    no
    Use Eigen3:                  yes (ver 3.3.7)
    Use OpenCV:                  yes (ver 3.2.0)

  Simulator:
    Ogre simulator:
    \- Use Ogre3D:               no
    \- Use OIS:                  no
    Coin simulator:
    \- Use Coin3D:               no
    \- Use SoWin:                no
    \- Use SoXt:                 no
    \- Use SoQt:                 no
    \- Use Qt5:                  no
    \- Use Qt4:                  no
    \- Use Qt3:                  no

  Media I/O:
    Use JPEG:                    yes (ver 62)
    Use PNG:                     yes (ver 1.6.36)
    \- Use ZLIB:                 yes (ver 1.2.11)
    Use OpenCV:                  yes (ver 3.2.0)
    Use stb_image (built-in):    no

  Real robots:
    Use Afma4:                   no
    Use Afma6:                   no
    Use Franka:                  no
    Use Viper650:                no
    Use Viper850:                no
    Use Kinova Jaco:             no
    Use aria (Pioneer):          no
    Use PTU46:                   no
    Use Biclops PTU:             no
    Use Flir PTU SDK:            no
    Use Parrot ARSDK:            no
    \-Use ffmpeg:                no
    Use Virtuose:                no
    Use qbdevice (built-in):     yes (ver 2.6.0)
    Use takktile2 (built-in):    yes (ver 1.0.0)

  GUI:
    Use X11:                     yes
    Use GTK:                     no
    Use OpenCV:                  yes (ver 3.2.0)
    Use GDI:                     no
    Use Direct3D:                no

  Cameras:
    Use DC1394-2.x:              yes (ver 2.2.5)
    Use CMU 1394:                no
    Use V4L2:                    yes (ver 1.16.3)
    Use directshow:              no
    Use OpenCV:                  yes (ver 3.2.0)
    Use Flycapture:              no
    Use Pylon:                   no

  RGB-D sensors:
    Use Realsense:               no
    Use Realsense2:              no
    Use Kinect:                  no
    \- Use libfreenect:          no
    \- Use libusb-1:             no
    \- Use pthread:              yes
    Use PCL:                     no
    \- Use VTK:                  no

  F/T sensors:
    Use atidaq (built-in):       no
    Use comedi:                  no
    Use IIT SDK:                 no

  Detection:
    Use zbar:                    yes (ver 0.22)
    Use dmtx:                    no
    Use AprilTag (built-in):     yes (ver 3.1.1)
    \- Use AprilTag big family:  no

  Misc:
    Use Clipper (built-in):      yes (ver 6.4.2)
    Use pugixml (built-in):      yes (ver 1.9.0)
    Use libxml2:                 yes (ver 2.9.4)

  Optimization:
    Use OpenMP:                  yes
    Use pthread:                 yes
    Use pthread (built-in):      no
    Use cxx standard:            11

  Documentation:
    Use doxygen:                 no

  Tests and samples:
    Use catch2 (built-in):       yes (ver 2.9.2)
    Tests:                       yes
    Demos:                       yes
    Examples:                    yes
    Tutorials:                   yes

  Install path:                  /usr/local

==========================================================
\endverbatim

\section install_raspberry_next Next tutorial

You are now ready to see the next \ref tutorial-getting-started that will show you how to use ViSP as a 3rd party to
build your own project on Raspberry Pi or on any other system. Then if you have a Raspberry Pi camera module, you can
also follow the \ref tutorial-tracking-blob especially subsection Tracking form v4l2 live cameras.

You may also be interested in \ref tutorial-install-crosscompiling-raspberry if you want to speed up the build process
or deploy ViSP on other Raspberry boards.

There is also \ref tutorial-mbot-vs that uses a Raspberry Pi in order to control a mBot Ranger educational robot
kit by visual-servoing.

*/