[imgui] Add feature bindings and remove feature example

[JackBoosY]

Since the binary generated by examples is rarely used, remove feature examples and add feature bindings.

Related: #10252 #8788.

Note: because the current feature tools still have generation problems, this PR only performs a simple separation feature.

All features passed in the following triplets test:

• x86-windows
• x64-windows
• x64-windows-static

[idcrook]

I found this issue while trying to resolve imgui install issue.

The header files and source files from imgui examples are used for bindings to call into imgui. And they sometimes change with imgui versions. Alongside examples and tools, there should be "bindings" included with result artifacts so that they can be found within the package.

$ ls -1 examples/imgui_impl_opengl3.* examples/imgui_impl_glfw.*
examples/imgui_impl_glfw.cpp
examples/imgui_impl_glfw.h
examples/imgui_impl_opengl3.cpp
examples/imgui_impl_opengl3.h

There is no build or binary required from these, so it should be safe to always include in result.
so something resembling

    # Install bindings
    file(GLOB IMGUI_BINDINGS ${SOURCE_PATH}/examples/*.h ${SOURCE_PATH}/examples/*.cpp)
    file(INSTALL ${IMGUI_BINDINGS} DESTINATION ${CURRENT_PACKAGES_DIR}/resources)

I used resources there as a placeholder for resources or bindings or what have you.

EDIT

example from conan version
https://github.com/conan-io/conan-center-index/blob/master/recipes/imgui/all/conanfile.py

self.copy(pattern="examples/imgui_impl_*", dst="res/bindings", src=self._source_subfolder, keep_path=False)

so a more appropriate GLOB might be

file(GLOB IMGUI_BINDINGS ${SOURCE_PATH}/examples/imgui_impl_* )

[idcrook]

Note: for thesebindings to work, it also relies on imgui_internal.h being available

• [ImGui] ImGui is meant to be extended using the imgui_internal.h header, but this header is not public #6665
• [imgui] Add feature internal to add imgui_internal.h #9125

which relies on other include files too, like imstb_textedit.h

[idcrook]

I have an example branch off master that works for demonstrating a "bindings" feature

Under a new feature [bindings]:

• copies imgui_impl_* to bindings
  • installing under share or share/imgui, etc. did not seem to "feel right"
• installs "internal" headers needed for compilation usings these bindings to include

https://github.com/idcrook/vcpkg/tree/imgui-trials

i was able to test in a build where these bindings from a vcpkg install are used.

[JackBoosY]

@idcrook Already follow your suggestion, but I prefer to install it's code files to include/bindings.

[idcrook]

@idcrook Already follow your suggestion, but I prefer to install it's code files to include/bindings.

looks good to me

[idcrook]

After looking over again, the build dependencies should be empty for “bindings” feature in the control file, as those are wrappers into imgui, and those files are part of imgui distribution.

If there is an “examples” feature still included, that would be where those build dependencies would probably go…

[PhoebeHui]

LGTM

[PhoebeHui]

/azp run

[helynranta]

Just dropping in a suggestion here (basically same thing that idcrook said):
If user wants the official bindings for sdl for example, he gets all of these other frameworks in the same package. There is really no point in having glfw3, sdl and allegro linked in same project.

My suggestion, to make this feature usable, is to provide CMake variable for source root of the bindings folder so that user could choose a bindings to build with and add it to include directories. Or something similar.

[JackBoosY]

@lerppana All files in buildtrees are temporary, we can only install the bindings source files in installed and then use them.

[helynranta]

Yeah sorry for my messed up explanation. What I mean is as a port user to use binding source files from vcpkg installed folder in my projects build (better explained what I mean? 😄). So whatever this feature is, without build-depends (see what idcrooks comment)

[strega-nil]

This looks good to me :)

[strega-nil]

/azp run

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