Use GNUInstallDirs to set installation locations

[waebbl]

The use of GNUInstallDirs ensures, the files are installed in common locations on all platforms.

Closes: #5496
Signed-off-by: Bernd Waibel waebbl-gentoo@posteo.net

[larshg]

I'm not that known to linux directory structure, but it seems to be the default to use GNUInstallDirs. So looks good to me.

[mikepurvis]

This change would be nice to get merged, as using GNUInstallDirs simplifies the split output story for packaging in Nix. One additional piece could be to eliminate the use of the PCL_ROOT variable altogether, particularly in blocks like this one:

pcl/PCLConfig.cmake.in

Lines 408 to 426 in aa7c679

	# check whether PCLConfig.cmake is found into a PCL installation or in a build tree
	if(EXISTS "${PCL_ROOT}/include/pcl-${PCL_VERSION_MAJOR}.${PCL_VERSION_MINOR}/pcl/pcl_config.h")
	# Found a PCL installation
	# pcl_message("Found a PCL installation")
	set(PCL_CONF_INCLUDE_DIR "${PCL_ROOT}/include/pcl-${PCL_VERSION_MAJOR}.${PCL_VERSION_MINOR}")
	set(PCL_LIBRARY_DIRS "${PCL_ROOT}/@LIB_INSTALL_DIR@")
	elseif(EXISTS "${PCL_ROOT}/include/pcl/pcl_config.h")
	# Found a non-standard (likely ANDROID) PCL installation
	# pcl_message("Found a PCL installation")
	set(PCL_CONF_INCLUDE_DIR "${PCL_ROOT}/include")
	set(PCL_LIBRARY_DIRS "${PCL_ROOT}/lib")
	elseif(EXISTS "${PCL_DIR}/include/pcl/pcl_config.h")
	# Found PCLConfig.cmake in a build tree of PCL
	# pcl_message("PCL found into a build tree.")
	set(PCL_CONF_INCLUDE_DIR "${PCL_DIR}/include") # for pcl_config.h
	set(PCL_LIBRARY_DIRS "${PCL_DIR}/@LIB_INSTALL_DIR@")
	else()
	pcl_report_not_found("PCL can not be found on this machine")
	endif()

Rather than assuming the built libraries are relative to some common root in the installed case, as this line does:

set(PCL_LIBRARY_DIRS "${PCL_ROOT}/@LIB_INSTALL_DIR@")

I believe it would be preferred to use the CMAKE_INSTALL_LIBDIR variable here, which CMake provides via its GNUInstallDirs implementation.

See: https://cmake.org/cmake/help/latest/module/GNUInstallDirs.html

[larshg]

@jspricke and @UnaNancyOwen Can you chime in on this change how it would work on debian and windows?

[UnaNancyOwen]

@larshg I checked this changes. It almost works fine on Windows and All-in-one Installer! 👍

For one thing from me, the installation directory path of the documentations seems to be just a little different from the path required by the generate script for all-in-one installer. Therefore, the link set by installer is broken. Perhaps, it should be corrected on these lines.

pcl/cmake/cpack_options.cmake.in

Lines 18 to 22 in 18fe557

	set(CPACK_NSIS_MENU_LINKS
	"share/doc/pcl-@PCL_VERSION_MAJOR@.@PCL_VERSION_MINOR@/tutorials/html/index.html" "Tutorials"
	"share/doc/pcl-@PCL_VERSION_MAJOR@.@PCL_VERSION_MINOR@/tutorials/html/sources" "Tutorials sources"
	"share/doc/pcl-@PCL_VERSION_MAJOR@.@PCL_VERSION_MINOR@/html/pcl-@PCL_VERSION_MAJOR@.@PCL_VERSION_MINOR@.chm" "Documentation"
	"http://www.pointclouds.org" "PCL Website")

pcl-@PCL_VERSION_MAJOR@.@PCL_VERSION_MINOR@ -> PCL

  set(CPACK_NSIS_MENU_LINKS
-             "share/doc/pcl-@PCL_VERSION_MAJOR@.@PCL_VERSION_MINOR@/tutorials/html/index.html" "Tutorials"
-             "share/doc/pcl-@PCL_VERSION_MAJOR@.@PCL_VERSION_MINOR@/tutorials/html/sources" "Tutorials sources"
-             "share/doc/pcl-@PCL_VERSION_MAJOR@.@PCL_VERSION_MINOR@/html/pcl-@PCL_VERSION_MAJOR@.@PCL_VERSION_MINOR@.chm" "Documentation"
+             "share/doc/PCL/tutorials/html/index.html" "Tutorials"
+             "share/doc/PCL/tutorials/html/sources" "Tutorials sources"
+             "share/doc/PCL/html/pcl-@PCL_VERSION_MAJOR@.@PCL_VERSION_MINOR@.chm" "Documentation"
              "http://www.pointclouds.org" "PCL Website")

[jspricke]

fine with me.