Export includes to allow other plugins to instantiate tactile displays

[guihomework]

This PR permits external plugins to re-use classes or plugin displays of rviz_tactile_plugins

Similar exports are done in the main rviz https://github.com/ros-visualization/rviz/blob/noetic-devel/CMakeLists.txt#L184

[guihomework]

the catkin_lint issue is relative to header files not being installed.

• up to now, in devel space, the rviz_tactile_plugin header files that I need in my package are included with no pkg_name in front of the header file, and compiles fine because those headers are at the root of src which is exported as seen in my commit

• If I install them however the build does not work in install_space because the headers are always installed in install/include/rviz_tactile_plugins/*.h while the current #include does not have the pkg_name as in #include <property.h>

• On the opposite if I edit the #includes, to look like #include <rviz_tactile_plugins/group_property.h> the install space compiles fine but the devel space compilation fails

  
  fatal error: rviz_tactile_plugins/group_property.h: No such file or directory
  33 | #include <rviz_tactile_plugins/group_property.h>

I do not manage to find a solution to install the header files correctly so that the compilation works for both devel and install space.

I tried to mimic what rviz does [here](https://github.com/ros-visualization/rviz/blob/6a234b4404c5ee71051f0b338ab8d5d2d931c27b/src/rviz/CMakeLists.txt) and [here](https://github.com/ros-visualization/rviz/blob/6a234b4404c5ee71051f0b338ab8d5d2d931c27b/src/rviz/default_plugin/CMakeLists.txt)
including the GereneratedExportHeader, as found [in this other branch](https://github.com/robomantic/tactile_toolbox/tree/export_includes_install) but I seem to not understand the concept fully yet

some mechanism must be set up so that in devel space one can still use the `#include <pkg_name/*.h>` even if files are under the folder src/ directly but I cannot figure out how.

@rhaschke Do you have any pointer or suggestion how to solve this install problem ?

[rhaschke]

The standard way to solve this issue is to move installed include files into folder include/<package>/ and declare INCLUDE_DIRS include. rviz has all its source and include files in src/rviz. Hence INCLUDE_DIRS src works there because includes are found both, from devel and install space, via rviz/*.h. You are also missing the actual install of files.

[guihomework]

Thanks for answering quickly. I indeed saw RViz uses source and header in src) but rviz_tactile_plugins uses the same way, and I am talking about the latter.

You are also missing the actual install of files.

I think in a second attempt in the new branch as pointed in my comment, I had the installation of the actual files, but they will necessarily go in include/rviz_tactile_plugins/*.h (we don't want them loose in include directly) and so I would still face the problem, because in devel they are found without package name. I will retry to solve this issue, but to be sure I understood, where do you expect the header files of rviz_tactile_plugins to be installed ?

[rhaschke]

The key difference between rviz and rviz_tactile_plugins is that the former has all files in src/<package>, while the latter has them in src only.

Where do you expect the header files of rviz_tactile_plugins to be installed ?

They should go - as you said - to include/rviz_tactile_plugins/*.h.

[rhaschke]

I just noticed that this repo's GHA fail for unrelated reasons. These issues are fixed now again. Note that I force-pushed melodic-devel. Please rebase your branch.

[guihomework]

@rhaschke now I understood that you were fine with changing the place of header files in the standard location in the source not only in the installed location. I will provide a new PR for that.