Extra parent folder ruins path resolution for internal files in OpenCV?

[krmrmethod]

Hello all,

I am trying to modernize a legacy Visual Studio project which uses the opencv library. For this, I've decided to use vcpkg in order to better manage the dependency versions. Now, I've encountered what I would say "weird behaviour" but I'm not sure if this is specific to the opencv library.

Basically, when I install the opencv package, vcpkg copies the built library in this folder

.\vcpkg_installed\x86-windows\x86-windows\include\opencv2.4

This means, when I try to include the files in my code I have to write them like this:

#include <opencv2.4/opencv2/opencv.hpp>

If I try to build my project you can already imagine what happens. I get a compiler error telling me that inside opencv.hpp the following include #include "opencv2/opencv_modules.hpp" couldn't be resolved.

It makes sense since the folders opencv2 and opencv should be placed directly under the include folder.

I also have tried with the newer opencvpackage and the same thing happened. It puts the library under .\vcpkg_installed\x86-windows\x86-windows\include\opencv4\opencv2

As a workaround I just setup my project properties inside Visual Studio to add the directory .\vcpkg_installed\x86-windows\x86-windows\include\opencv4\ to it's additional include directories, but I thought vcpkg was supposed to take care of this? Am I missing something? Some extra step to tell vcpkg to not create that extra root folder?

Thanks in advance!

[Moin2002-tech]

The behavior you’re seeing is actually normal. Starting with OpenCV 4, the library’s headers are placed inside an extra opencv4 folder (for example: vcpkg_installed\x86-windows\include\opencv4\opencv2). This is intentional it prevents conflicts between OpenCV 3 and 4. When including headers in your code, you should still write #include <opencv2/opencv.hpp> and not include the opencv4 part manually. To make this work, just make sure your project’s include path points to vcpkg_installed\x86-windows\include\opencv4. If you’ve already run vcpkg integrate install, Visual Studio should automatically handle this for you, and you won’t need to change project settings manually. The difference between #include "..." and #include <...> is simple: use quotes for your own project files, and angle brackets for external libraries like OpenCV.

[krmrmethod]

That makes total sense.

Yes, in my code I've written the includes using <> brackets. The includes I mentioned using "" come from the internal files of OpenCV (which I didn't touch obviously).

Even after running vcpkg integrate install beforehand I still had to manually add the path vcpkg_installed\x86-windows\include\opencv4 to my include directories inside the Visual Studio project settings after installing the library.

That's why I am asking. vcpkg didn't automatically manage opencv's specific path and I had to add it manually.