Using OpenCV's CMake module targets instead of including all libraries directly? - c++

Question

Problem: I have a project which uses OpenCV. I'm able to switch to what ever the latest version is if need be. My project uses CMake. I currently integrate opencv like so:
# OPENCV package
find_package(OpenCV)
add_library(opencv INTERFACE)
target_include_directories(opencv
INTERFACE
${OpenCV_INCLUDE_DIRS})
target_link_libraries(opencv
INTERFACE
${OpenCV_LIBS})
add_executable(opencv_example example.cpp)
target_link_libraries(opencv_example
PRIVATE
opencv
)
I cannot find examples of OpenCV using explicit module dependency targets. In order to not cruff up global includes unessessarily or leave naked variables laying around. I create an interface target for OpenCV and use this interface target instead of doing what OpenCV CMake example recommends:
# Find OpenCV, you may need to set OpenCV_DIR variable
# to the absolute path to the directory containing OpenCVConfig.cmake file
# via the command line or GUI
find_package(OpenCV REQUIRED)
# Declare the executable target built from your sources
add_executable(opencv_example example.cpp)
# Link your application with OpenCV libraries
target_link_libraries(opencv_example ${OpenCV_LIBS})
My question is it possible to just use OpenCV's module targets instead of having to bringing the whole kitchen sink along?
example (see module list here):
...
add_executable(opencv_example example.cpp)
target_link_libraries(opencv_example
PRIVATE
opencv::core
opencv::video
opencv::imgproc
)
thus I only get dependencies required for the modules I actually use. I looked through the OpenCV repository, but it is full of custom cmake macros and functions and It is difficult to see where a target is declared, let alone if it can be accessed from find_package.

Answer 1

While opencv::module doesn't work, if you use find_package, starting from at most OpenCV3.2 (it may have been available before) you can use targets like opencv_module for example with:
find_package(OpenCV REQUIRED COMPONENTS core imgproc video)
add_executable(opencv_example example.cpp)
target_link_libraries(opencv_example
PRIVATE
opencv_core
opencv_video
opencv_imgproc
)
I found out these targets were exported here:https://github.com/opencv/opencv/issues/8028#issuecomment-273419374