CMake compile options for libpng

Question

I am using libpng in my project. Right now, I can compile my project with: g++ *.cpp `libpng-config --ldflags`

I want to switch to using CMake for easy recompiling but I don't know what to do for the libpng part. How do I provide `libpng-config --ldflags` with CMake?

Answer 1

I finally solved it using find_package. Thanks to this blog post.

find_package(PNG REQUIRED)
include_directories(${PNG_INCLUDE_DIR})
target_link_libraries(${MY_EXEC} ${PNG_LIBRARY})

Answer 2

I think the recommended and portable way it should be done using pkg-config, something like this:

# search for pkg-config
include (FindPkgConfig)
if (NOT PKG_CONFIG_FOUND)
    message (FATAL_ERROR "pkg-config not found")
endif ()

# check for libpng
pkg_check_modules (LIBPNG libpng16 REQUIRED)
if (NOT LIBPNG_FOUND)
    message(FATAL_ERROR "You don't seem to have libpng16 development libraries installed")
else ()
    include_directories (${LIBPNG_INCLUDE_DIRS})
    link_directories (${LIBPNG_LIBRARY_DIRS})
    link_libraries (${LIBPNG_LIBRARIES})
endif ()
add_executable (app_png ${_MYSOURCES} ${LIBPNG_LINK_FLAGS})