WIP: flowchart (aka NodeGraph) visualization

[drzraf]

Building a flowchart to visualize (and hopefully control) command's graph to open the doors of more complex multiple IN/OUT workflow is a must-have (using NodeGraphQt)

It's a major feature of ala ImagePlay :

This allows to apply transformations expecting multiple inputs (eg: a custom kernel + image or multiple input images), transformation providing multiple outputs (eg: different channels or region of interest + transformed image) and enjoin branching (trying multiplee paths variation/combination)

A solid flowchart UX + and a nice CV2 command-description using best introspective Python features would pave the way to a really nice OpenCV UI and make a small code-base easier to build upon than [rather unmaintained these days] ImagePlay)
I wish the 7k LoC of core CV2 <-> UI mapping (including multiple in/out handling) could be reimplemented in a mostly declarative commands.txt using advanced Python libraries/language constructs (#10 ?)

Regarding this PR, it aimed to be a minimally intrusive PoC provided on it's own distinct branch... but NodeGraph dependency actually uses qtpy instead of PySide6 (see pr #7 and #8)

I believe the flowchart could be the main UI instead of just "listening" to the button (as currently done in this PoC) and each element could show a live preview of the image.

Happy to further discuss it.

[ArthurDelannoyazerty]

TODO :
Add qtpy in environment.py

I cannot test because of error : "ImportError: No Qt binding were found."

[ArthurDelannoyazerty]

I am gratefull for you to work on this projet, but I must warn you that I didn't created the program for multiple input/output because it was meant to be simple at start. So changing this could be a huge amount of work.

I didn't know about ImagePlay and NodeGraphQt before you mentionned it, but for multiple input/output it seems a good thing to have instead of a static list or matrix of image a the top of the window (and also it looks better !)

For now I cannot merge this branch in the main because I cannot execute it when I re create the environment from en yml file.

Happy to see someone interested in this project !

[drzraf]

I force-pushed to fix the dependency. qtpy is a wrapper and doesn't install a specific backend at first. Maybe the PySide6 could still be "suggested" as part of the requirements?

Anyway, the PR is just a preliminary PoC aimed at discussing this possible development of such a structural change. Nothing to be merged as-is.
Would you describe a bit more the part of the layout you're ready to impact and these you're rather not touch for now and/or possible implementation preferences?

[ArthurDelannoyazerty]

Ok for pyqt then. For the environment it could be good to add Pyside6 so that environment can works out of the box. For me this still doesn't work (ImportError: No Qt binding were found.), Does your code works if you just install the conda environment.yml ? If not it should be corrected for everyone to use it easily.

For the changes, there is no real resctriction since it's open source. But if you manage to change the opencv command from SISO to MIMO (for images), then the main thing to change would be the UI : the top pipeline can be changed to your node interface. And then the button panel can also be erased because the arrow from the node interface is the 'button'. But for now I think that the UI is not the main focus but the change from SISO to MIMO.

Also until a branch work, I will not merge it with the main because the main should always be working.

For now I don't think that the command file must be modified because it's working ok, but if SISO->MIMO need this file to change then feel free to modify everything you want !