Create Overview Scan panel from WideFieldAcquisition.py

[lizziewylie]

Fixes nion-software/nion-internal#381

[CLAassistant]

All committers have signed the CLA.

[cmeyer]

Minor drive-by comments. I'm aware this is draft, btw.

[cmeyer]

I'm only adding review for coding style, not for functionality or general algorithm logic.

[Brow71189]

I haven't tried it, just a comment from reading through the code inline below. Apart from that it looks fine.

[MattRoyle]

Mostly pedantic. Main bits are suggesting that the exporting is done via existing export functionality rather than introducing a new library dependency PIL. The UI line edit handling is done on a per function basis, converting to integers, exiting early if the value is too large. I think using Converters in tandem with property getters and setters would make the code more readable.

[MattRoyle]

Some issues with the defocus logic and how wide this panel appears.

[Brow71189]

Some things I notices while reading through the code. Nothing major, but would be nice to fix I think.

[cmeyer]

I'm not following closely along here, but why wouldn't the output of this be a data item?

[cmeyer]

Independent of requirements and design prerequisites, I don't think this project belongs in experimental. It is an acquisition project and would introduce a package dependency that I don't want to have. It's fine for development here, as long as it is a PR, but ultimately will have to live somewhere else - perhaps nionswift-instrumentation-kit.

A low level acquisition procedure (basically the same as your acquisition method) already exists in the instrumentation kit: AcquisitionLibrary.create_table_of_scans_acquisition_procedure. If it isn't sufficient for this use case, please file an issue with what you need.

This project will also need comprehensive tests.

This project also needs to be split into model and view (UI) packages.