Opencv_contrib: `face` module does not generate python binding correctly.

[multics]

Some methods in class in file like facemark_train.hpp does not do cv_export. Is this by design or is it a defect.

[berak]

it's more a defect in the design (imho).

the c++ functions / interfaces there contain function pointers, void* , Param structs, and a lot more things, that can't be easily wrapped into python/java automatically.

the original author clearly did not have prospective python users in mind.
for now, you'll have to use the c++ examples to train your model.
(there are also still problems, using those from python)

[multics]

The c++ demos are great, and work well. I was trying to use python binding from pip - opencv-contrib-python, which was based on 3.4.2, and found that function and classes of face landmarks did not work. So I took a look on opencv side, found this "defect in the design".

And surely I do understand the difficulties when trying to wrap c++ into python sometimes. I do appreciate that so many contributors put a lot of effort on this project, and people like me could use it freely (thanks very much!). I've noticed @alalek mark this issue as feature for category face. I am glad, and hope this could be available soon. 🥇

Thanks again!