[KPhotoAlbum] CMakeLists.txt and libkface

[Tobias Leupold]

Hi list!

I recently had a small conversation with the Gentoo guys maintaining the KPA
ebuilds about how to handle optional dependencies like libkface. Currently,
this is the way we search for it (added by Pino Toscano):

find_package(Kface 3.5.0 CONFIG)
set(KFACE_FOUND ${Kface_FOUND})
if(KFACE_FOUND)
set(KFACE_LIBRARIES ${Kface_LIBRARIES})
INCLUDE_DIRECTORIES(${Kface_INCLUDE_DIR})
else()
unset(KFACE_FOUND)
pkg_check_modules(KFACE libkface>=3.5.0)
if(KFACE_FOUND)
INCLUDE_DIRECTORIES(${KFACE_INCLUDE_DIR})
endif()
endif(KFACE_FOUND)
macro_bool_to_01(KFACE_FOUND HAVE_KFACE)

This includes a "fallback" search if no cmake module for libkface is found.
But it also (apparently, I'm not a cmake pro ;-) makes it hard to skip the
libkface inclusion if the library is present, but should not be used to build
KPA.

Michael Palimaka from Gentoo said that if it's possible, we should use
find_package. It's true that older versions of libkface do not ship a cmake
module. But we need at least libkface 3.5.0 (currently only available from git
master), which comes with a cmake module. So if we have some libkface version
installed without it, it's too old anyway, so I think we don't need this
fallback check.

So I tried it with:

find_package(Kface 3.5.0 CONFIG)
macro_bool_to_01(KFACE_FOUND HAVE_KFACE)
if(KFACE_FOUND)
INCLUDE_DIRECTORIES(${KFACE_INCLUDE_DIR})
endif(KFACE_FOUND)

which works just fine here, with and without libkface, and will also play nice
with Portage and USE flags on Gentoo. Would you please verify that this is
also okay on other systems?

Thanks in advance!

Cheers, Tobias

[Johannes Zarl]

Post by Tobias Leupold
find_package(Kface 3.5.0 CONFIG)
macro_bool_to_01(KFACE_FOUND HAVE_KFACE)
if(KFACE_FOUND)
INCLUDE_DIRECTORIES(${KFACE_INCLUDE_DIR})
endif(KFACE_FOUND)
which works just fine here, with and without libkface, and will also play
nice with Portage and USE flags on Gentoo. Would you please verify that
this is also okay on other systems?

Yes, this works also with other systems.

I've pushed this to git master, with the slight change of using Kface_FOUND
instead of KFACE_FOUND. Since the uppercase variable is only used for
compatibility, this should reduce confusion as to which variable should be set
to false when one wants to disable libkface.

Cheers,
Johannes