[CMake] Using different installs/versions of the OpenCV library

[Bart Vandewoestyne]

On 02/14/2013 12:26 PM, Andreas Haferburg wrote:
> Does CMake find 2.4.3 if you remove 2.3.1? CMake probably doesn't even
> look in /tmp/. You could try moving it to /usr/share/OpenCV-2.4.3/.
>
> If the version arg doesn't work, I think your best bet is to use a
> naming convention for the library directories (or create symlinks), e.g.
> <lib>-<version>-<arch>, then use that directory in the find script.
>
> Andreas

The link_directories() command seems to do the trick...

I'm currently at this, which seems to work:

----------------------------------------------------------------------------
# Change this depending on what you need.
set(USE_TMP_OPENCV TRUE)

if(USE_TMP_OPENCV)

   #Manual setting: OpenCV from /tmp/opencv_install
   set(OpenCV_INCLUDE_DIR "/tmp/opencv_install/include/opencv")
   include_directories(${OpenCV_INCLUDE_DIR})
   set(OpenCV_LIBS 
"opencv_gpu;opencv_contrib;opencv_legacy;opencv_objdetect;opencv_calib3d;opencv_features2d;opencv_video;opencv_highgui;opencv_ml;opencv_imgproc;opencv_flann;opencv_core")
   link_directories(/tmp/opencv_install/lib)

elseif(USE_FAT_OPENCV)

   # Manual setting: OpenCV from FAT
   set(OpenCV_INCLUDE_DIR "/bla/bla/bla/opencv")
   include_directories(${OpenCV_INCLUDE_DIR})
   set(OpenCV_LIBS 
"opencv_gpu;opencv_contrib;opencv_legacy;opencv_objdetect;opencv_calib3d;opencv_features2d;opencv_video;opencv_highgui;opencv_ml;opencv_imgproc;opencv_flann;opencv_core")
   link_directories(/bla/bla/bla/lib)

else()

   # Automatic discovery.
   find_package( OpenCV REQUIRED )

endif()
----------------------------------------------------------------------------

This still has the disadvantage that I have to change my CMakeLists.txt 
each time I want to switch.  I would like to be able to switch using 
command-line arguments.  I tried with cmake -d USE_TMP_OPENCV and stuff 
like that, but somehow the wrong version was used if i did not specify a 
-D argument (hoping for the automatic discovery).  I guess I'll have to 
freshen up my understanding of if-elseif-else control flow and 
specifying variables on the cmake command line... tim to rtfm! ;-)

Regards,
Bart