.. _Linux_Eclipse_Usage:
Using OpenCV with Eclipse (plugin CDT)
****************************************
.. note::
Two ways, one by forming a project directly, and another by CMake
Prerequisites
===============
1. Having installed `Eclipse <http://www.eclipse.org/>`_ in your workstation (only the CDT plugin for C/C++ is needed). You can follow the following steps:
* Go to the Eclipse site
* Download `Eclipse IDE for C/C++ Developers <http://www.eclipse.org/downloads/packages/eclipse-ide-cc-developers/heliossr2>`_ . Choose the link according to your workstation.
#. Having installed OpenCV. If not yet, go :ref:`here <Linux-Installation>`.
Making a project
=================
1. Start Eclipse. Just run the executable that comes in the folder.
#. Go to **File -> New -> C/C++ Project**
.. image:: images/a0.png
:alt: Eclipse Tutorial Screenshot 0
:align: center
#. Choose a name for your project (i.e. DisplayImage). An **Empty Project** should be okay for this example.
.. image:: images/a1.png
:alt: Eclipse Tutorial Screenshot 1
:align: center
#. Leave everything else by default. Press **Finish**.
#. Your project (in this case DisplayImage) should appear in the **Project Navigator** (usually at the left side of your window).
.. image:: images/a3.png
:alt: Eclipse Tutorial Screenshot 3
:align: center
#. Now, let's add a source file using OpenCV:
* Right click on **DisplayImage** (in the Navigator). **New -> Folder** .
.. image:: images/a4.png
:alt: Eclipse Tutorial Screenshot 4
:align: center
* Name your folder **src** and then hit **Finish**
* Right click on your newly created **src** folder. Choose **New source file**:
* Call it **DisplayImage.cpp**. Hit **Finish**
.. image:: images/a7.png
:alt: Eclipse Tutorial Screenshot 7
:align: center
#. So, now you have a project with a empty .cpp file. Let's fill it with some sample code (in other words, copy and paste the snippet below):
.. code-block:: cpp
#include <opencv2/opencv.hpp>
using namespace cv;
int main( int argc, char** argv )
{
Mat image;
image = imread( argv[1], 1 );
if( argc != 2 || !image.data )
{
printf( "No image data \n" );
return -1;
}
namedWindow( "Display Image", WINDOW_AUTOSIZE );
imshow( "Display Image", image );
waitKey(0);
return 0;
}
#. We are only missing one final step: To tell OpenCV where the OpenCV headers and libraries are. For this, do the following:
* Go to **Project-->Properties**
* In **C/C++ Build**, click on **Settings**. At the right, choose the **Tool Settings** Tab. Here we will enter the headers and libraries info:
a. In **GCC C++ Compiler**, go to **Includes**. In **Include paths(-l)** you should include the path of the folder where opencv was installed. In our example, this is ``/usr/local/include/opencv``.
.. image:: images/a9.png
:alt: Eclipse Tutorial Screenshot 9
:align: center
.. note::
If you do not know where your opencv files are, open the **Terminal** and type:
.. code-block:: bash
pkg-config --cflags opencv
For instance, that command gave me this output:
.. code-block:: bash
-I/usr/local/include/opencv -I/usr/local/include
b. Now go to **GCC C++ Linker**,there you have to fill two spaces:
First in **Library search path (-L)** you have to write the path to where the opencv libraries reside, in my case the path is:
::
/usr/local/lib
Then in **Libraries(-l)** add the OpenCV libraries that you may need. Usually just the 3 first on the list below are enough (for simple applications) . In my case, I am putting all of them since I plan to use the whole bunch:
opencv_core
opencv_imgproc
opencv_highgui
opencv_ml
opencv_video
opencv_features2d
opencv_calib3d
opencv_objdetect
opencv_contrib
opencv_legacy
opencv_flann
.. image:: images/a10.png
:alt: Eclipse Tutorial Screenshot 10
:align: center
If you don't know where your libraries are (or you are just psychotic and want to make sure the path is fine), type in **Terminal**:
.. code-block:: bash
pkg-config --libs opencv
My output (in case you want to check) was:
.. code-block:: bash
-L/usr/local/lib -lopencv_core -lopencv_imgproc -lopencv_highgui -lopencv_ml -lopencv_video -lopencv_features2d -lopencv_calib3d -lopencv_objdetect -lopencv_contrib -lopencv_legacy -lopencv_flann
Now you are done. Click **OK**
* Your project should be ready to be built. For this, go to **Project->Build all**
In the Console you should get something like
.. image:: images/a12.png
:alt: Eclipse Tutorial Screenshot 12
:align: center
If you check in your folder, there should be an executable there.
Running the executable
========================
So, now we have an executable ready to run. If we were to use the Terminal, we would probably do something like:
.. code-block:: bash
cd <DisplayImage_directory>
cd src
./DisplayImage ../images/HappyLittleFish.png
Assuming that the image to use as the argument would be located in <DisplayImage_directory>/images/HappyLittleFish.png. We can still do this, but let's do it from Eclipse:
#. Go to **Run->Run Configurations**
#. Under C/C++ Application you will see the name of your executable + Debug (if not, click over C/C++ Application a couple of times). Select the name (in this case **DisplayImage Debug**).
#. Now, in the right side of the window, choose the **Arguments** Tab. Write the path of the image file we want to open (path relative to the workspace/DisplayImage folder). Let's use **HappyLittleFish.png**:
.. image:: images/a14.png
:alt: Eclipse Tutorial Screenshot 14
:align: center
#. Click on the **Apply** button and then in Run. An OpenCV window should pop up with the fish image (or whatever you used).
.. image:: images/a15.jpg
:alt: Eclipse Tutorial Screenshot 15
:align: center
#. Congratulations! You are ready to have fun with OpenCV using Eclipse.
==================================================
V2: Using CMake+OpenCV with Eclipse (plugin CDT)
==================================================
Say you have or create a new file, *helloworld.cpp* in a directory called *foo*:
.. code-block:: cpp
#include <opencv2/opencv.hpp>
using namespace cv;
int main ( int argc, char **argv )
{
Mat img(480, 640, CV_8U);
putText(img, "Hello World!", Point( 200, 400 ), FONT_HERSHEY_SIMPLEX | FONT_ITALIC, 1.0, Scalar( 255, 255, 0 ));
imshow("My Window", img);
waitKey();
return 0;
}
1. Create a build directory, say, under *foo*: ``mkdir /build``. Then ``cd build``.
#. Put a *CmakeLists.txt* file in build:
.. code-block:: bash
PROJECT( helloworld_proj )
FIND_PACKAGE( OpenCV REQUIRED )
ADD_EXECUTABLE( helloworld helloworld.cxx )
TARGET_LINK_LIBRARIES( helloworld ${OpenCV_LIBS} )
#. Run: ``cmake-gui ..`` and make sure you fill in where opencv was built.
#. Then click ``configure`` and then ``generate``. If it's OK, **quit cmake-gui**
#. Run ``make -j4`` *(the ``-j4`` is optional, it just tells the compiler to build in 4 threads)*. Make sure it builds.
#. Start ``eclipse`` . Put the workspace in some directory but **not** in ``foo`` or ``foo\\build``
#. Right click in the ``Project Explorer`` section. Select ``Import`` And then open the ``C/C++`` filter. Choose *Existing Code* as a Makefile Project``
#. Name your project, say *helloworld*. Browse to the Existing Code location ``foo\\build`` (where you ran your cmake-gui from). Select *Linux GCC* in the *"Toolchain for Indexer Settings"* and press *Finish*.
#. Right click in the ``Project Explorer`` section. Select ``Properties``. Under ``C/C++ Build``, set the *build directory:* from something like ``${workspace_loc:/helloworld}`` to ``${workspace_loc:/helloworld}/build`` since that's where you are building to.
a. You can also optionally modify the ``Build command:`` from ``make`` to something like ``make VERBOSE=1 -j4`` which tells the compiler to produce detailed symbol files for debugging and also to compile in 4 parallel threads.
#. Done!