[ITK] How to avoid NIFTI header files from being installed?

[Matt McCormick]

On Mon, Sep 18, 2017 at 9:32 AM, Niels Dekker <niels-xtk at xs4all.nl> wrote:
>>> However, when doing an INSTALL, nifti1.h and nifti1_io.h (as well as
>>> itk_nifti_mangle.h) are still copied to the user's install directory
>
>
> Matt McCormick replied:
>>
>> To avoid this, a CMake option, ITK_USE_SYSTEM_NIFTI could be set up
>> similar to other third party modules. The CMake configuration code
>> needs to be added to the module so it can find the system NIFTI and
>> export the required build information to other modules.
>
>
> Thanks for your reply, Matt! ITK_USE_SYSTEM_NIFTI might be interesting
> option.
>
> However, I was thinking of a different problem: Suppose my application MyApp
> depends on both ITK (installed at the ITK_INSTALL_PREFIX directory), and "my
> own version" of niftilib. In this case, I want ITK to internally still use
> the ITK version of niftilib. MyApp has ITK_INSTALL_PREFIX/include/ITK-4.12
> as one of its include directories. However, when a CXX file of MyApp does
> #include <nifti1.h>, it should #include the niftilib file from "my own
> version" of niftilib, not the one internally used by ITK!
>
> Now I see there already exists a CMake option to stop ITK niftilib header
> files from being installed: NIFTI_INSTALL_NO_DEVELOPMENT  It's being used in
> the CMakeLists.txt files at ThirdParty\NIFTI\src\nifti\znzlib and
> ThirdParty\NIFTI\src\nifti\niftilib:
> https://github.com/Kitware/ITK/blob/v4.12.2/Modules/ThirdParty/NIFTI/src/nifti/niftilib/CMakeLists.txt#L29
>
> I was about to suggest to set NIFTI_INSTALL_NO_DEVELOPMENT ON by default.
> But now I see, "gifti_io.h" does #include <nifti1_io.h>:
> https://github.com/Kitware/ITK/blob/v4.12.2/Modules/ThirdParty/GIFTI/src/gifticlib/gifti_io.h#L6
>
> "gifti_io.h" is also copied to ITK_INSTALL_PREFIX, during an ITK install. So
> ITK users can only set NIFTI_INSTALL_NO_DEVELOPMENT ON when they do not need
> to #include this header file. And actually, "itkGiftiMeshIO.h" does #include
> "gifti_io.h":
> https://github.com/Kitware/ITK/blob/v4.12.2/Modules/IO/Mesh/include/itkGiftiMeshIO.h#L27
>
> This #include "gifti_io.h" could be hidden by moving the include statement
> from "itkGiftiMeshIO.h" to "itkGiftiMeshIO.cxx". That could be done by
> adding a "proxy mechanism" to itk::GiftiMeshIO, similar to what we added to
> itk::NiftiIO. Do you think that would be a good idea?

Yes, great idea :-)