Using libopenshot in C++ CMake project

[federicomassa]

System Details:

Operating System / Distro: Ubuntu
OpenShot Version: 0.1.8

Issue Description and steps to reproduce:
Sorry for the very basic questions, I am probably missing some basic CMake concept. The issue is pretty simple: I have a C++ CMake project and I want to use Openshot to produce a video.

1)I cannot find a Cmake module to be able to do find_package(openshot). But this is secondary, I have written my finder, but it seems odd to me that it is not already provided in a CMake-based project.
2) Once I find the openshot library, I cannot do #include "OpenShot.h" because it doesn't find the external dependencies (like JuceLibraries/*.h in openshot-audio library). Usually, when I write my own libraries, I solve this just by using target_link_libraries, but this relies on the writer of the library to have defined an include interface in a target_include_directories.

Again, I am probably missing something very easy, so forgive me but as you probably know CMake's documentation really lacks on clarity (in my opinion, at least).

[ 97%] Built target openshot
[ 97%] Building CXX object Tests/HighwayViewer/CMakeFiles/TOpenShot.dir/TOpenShot.cpp.o
In file included from /home/federico-asus/Simulator/LocalMonitor/Tests/HighwayViewer/../../Utility/libopenshot-0.1.8/include/OpenShot.h:99:0,
                 from /home/federico-asus/Simulator/LocalMonitor/Tests/HighwayViewer/TOpenShot.cpp:2:
/home/federico-asus/Simulator/LocalMonitor/Tests/HighwayViewer/../../Utility/libopenshot-0.1.8/include/AudioBufferSource.h:40:40: fatal error: JuceLibraryCode/JuceHeader.h: No such file or directory
compilation terminated.
Tests/HighwayViewer/CMakeFiles/TOpenShot.dir/build.make:62: recipe for target 'Tests/HighwayViewer/CMakeFiles/TOpenShot.dir/TOpenShot.cpp.o' failed
make[3]: *** [Tests/HighwayViewer/CMakeFiles/TOpenShot.dir/TOpenShot.cpp.o] Error 1
CMakeFiles/Makefile2:1321: recipe for target 'Tests/HighwayViewer/CMakeFiles/TOpenShot.dir/all' failed
make[2]: *** [Tests/HighwayViewer/CMakeFiles/TOpenShot.dir/all] Error 2
CMakeFiles/Makefile2:1333: recipe for target 'Tests/HighwayViewer/CMakeFiles/TOpenShot.dir/rule' failed
make[1]: *** [Tests/HighwayViewer/CMakeFiles/TOpenShot.dir/rule] Error 2
Makefile:496: recipe for target 'TOpenShot' failed
make: *** [TOpenShot] Error 2

[DylanC]

@jonoomph - Any idea on this one?

[federicomassa]

NB In #1 it is described a similar problem, but in that case the include issue appears (interestingly on the same Juce header file) already when building libopenshot. In my case, instead, I can build libopenshot, but I cannot use it in a different project.

[federicomassa]

So, I have found a temporary solution which I don't really like because it involves changing your src/CMakeLists.txt file, but it works. Before explaining my solution, I should clarify that I have copied libopenshot into my project and I am building it like it was a module of my own project. However, I think this will work even when libopenshot is normally installed into the system, but I haven't tried it yet because it is not a priority for me.

So, I have just put, for each include_directories(${PATH}) command in src/CMakeLists.txt file, a call to target_include_directories(openshot PUBLIC ${PATH}) at the end of the file (plus another one for ${headers} variable).

target_include_directories(openshot PUBLIC ${ImageMagick_INCLUDE_DIRS})
target_include_directories(openshot PUBLIC ${FFMPEG_INCLUDE_DIR})
target_include_directories(openshot PUBLIC ${LIBOPENSHOT_AUDIO_INCLUDE_DIRS})
target_include_directories(openshot PUBLIC ${Qt5Widgets_INCLUDE_DIRS})
target_include_directories(openshot PUBLIC ${Qt5Core_INCLUDE_DIRS})
target_include_directories(openshot PUBLIC ${Qt5Gui_INCLUDE_DIRS})
target_include_directories(openshot PUBLIC ${Qt5Multimedia_INCLUDE_DIRS})
target_include_directories(openshot PUBLIC ${Qt5MultimediaWidgets_INCLUDE_DIRS})

if (BLACKMAGIC_FOUND)
		# Include headers (needed for compile)
		target_include_directories(openshot PUBLIC ${BLACKMAGIC_INCLUDE_DIR})
endif()

target_include_directories(openshot PUBLIC ${ZMQ_INCLUDE_DIRS})

if (USE_SYSTEM_JSONCPP)
	target_include_directories(openshot PUBLIC ${JSONCPP_INCLUDE_DIRS})
else()
	target_include_directories(openshot PUBLIC ../thirdparty/jsoncpp/include)
endif(USE_SYSTEM_JSONCPP)

target_include_directories(openshot PUBLIC ${headers})

This way, CMake handles the dependencies automatically and I can do, from my libraries, something like:

target_link_libraries(MyProject openshot)
target_include_directories(MyProject PUBLIC ${openshot_INCLUDE_DIR})

(This works in my case because openshot is built inside my project, but in general this should be done after an appopriate find_library/find_path or find_package call)

where you should set openshot_INCLUDE_DIR variable to your own path (possibly just writing a FindOpenShot.cmake module and calling find_package(openshot) ). After this, you should be able to include libopenshot headers simply with #include "OpenShot.h" .

Again, I do not really like this solution, but it's the best I could do to make this work.
Also, instead of just adding at the end of the file target_include_directories like I did, it would be better to find a way to replace the include_directories commands with target_include_directories, but I did not do that because target_include_directories requires the name of the library to be already defined, which is not in this case (at least for the first include_directories calls).

[stale]

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