Allow for showing vectorscope and waveform at the same time

[dtorop]

Is your feature request related to a problem? Please describe.
It can be annoying to switch between vectorscope and waveform scopes while working on an image. For some iops (e.g. exposure, sigmoid, or agx) it's really helpful to see the waveform while adjusting. For other iops (e.g. color calibration), the vectorscope can be helpful. Some iops (e.g. color balance rgb) benefit from seeing both waveform and vectorscope. Some iops can cause subtle changes to chromaticity, so it is good to have the vectorscope up to detect that.

Describe the solution you'd like
Be able to display both the vectorscope and the waveform.

Alternatives

• Have the scopes module change between vectorscope and waveform depending on which iop (or even which slider within the iop) is currently active.
• Set up shortcuts to switch between waveform and vectorscope.

Additional context
See #20337 for a quick implementation of showing both vectorscope and waveform. That PR also has some descriptions/mockups of a few possible solutions (e.g. side by side, above/beneath, expandable, special purpose button).

I'm assuming that most users of vectorscope would want to pair it with waveform (rather than histogram or RGB parade).

Very interested in thoughts on an appealing implementation (or how others use the scopes), whether here or on #20337.

[SilvioGrosso]

Hello @dtorop

Thanks a lot for this proposal!
I am sure it would be an interesting feature for darktable 😄
You have also beatutifully explained your proposal on your ancillary Pull requests.

With Shotcut, an open source video editor, as regards its color grading options, this feature is already implemented. Once in a while I personally take advantage of it: it works even for pictures and not only videos.

It is also implemented within other video editors. E.g. DaVinci Resolve:
https://www.youtube.com/watch?v=Fmdkmtx64ac

From what I am aware of, I suppose it would be the very first implementation among open source RAW editors.

[Donatzsky]

It is also implemented within other video editors. E.g. DaVinci Resolve:
https://www.youtube.com/watch?v=Fmdkmtx64ac

That CIE diagram is pretty neat, and could be a useful addition to DT.

[dtorop]

That CIE diagram is pretty neat, and could be a useful addition to DT.

Thank you both for thoughts. A CIE diagram is something I've been dreaming of for a while. As well as some sort of 3D way to render colorspace -- it's really clear when adjusting color in vectorscope that we're looking at a 2D view of 3D movements. For now, I've got the very simple implementation of split waveform/vectorscope. Path forward could be:

1. integrate that split waveform/vectorscope (scopes: add waveform/vectorscope split mode #20349)
2. modularize the scopes with minimal change to UI (WIP)
3. UI improvements/refinements
4. new scopes (e.g. CIE) or variants (e.g. luminance-only waveform)

I can't guarantee how my time will look in coming weeks/months (I can't promise timely steps 3 & 4), but good to be chipping away at this and gathering thoughts.

[SilvioGrosso]

Hello @dtorop

new scopes (e.g. CIE) or variants (e.g. luminance-only waveform)

A CIE new scope would be too good to be true 😄

Needless to say, do take your time to implement whatever bug-fixing or new feature you desire.
Darktable is already an incredible piece of sofware since its code is open source and it is available for everyone to play with and have fun.
Whatever your results: thanks a lot in advance!