Add auto fading for off-diagonal blocks

[ewu63]

Purpose

Basically, this is meant to make it easier to make a sequence of diagrams with different blocks faded. Instead of having to manually specify which off-diagonal components are faded, I've added some logic (with some options) to automatically decide if off-diagonal components connected to the faded diagonal components are to be faded.

This is still a fairly crude implementation, I'm happy to iterate on this PR to figure out a better API/implementation. Some initial thoughts:

• have a finalize function that gets called when we write out the TeX file, to sort out the logic after everything's added properly
• more logic to decide whether or not to shade connections if one or both sides are shaded

Expected time until merged

As long as it takes.

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (non-backwards-compatible fix or feature)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Documentation update
• Maintenance update
• Other (please describe)

Testing

Checklist

• I have run flake8 and black to make sure the code adheres to PEP-8 and is consistently formatted
• I have run unit and regression tests which pass locally with my changes
• I have added new tests that prove my fix is effective or that my feature works
• I have added necessary documentation

[lamkina]

Something else to consider, it would be nice if the unfaded connections would come after the faded connections in the tikz file. Tiks works with layers so if faded connections are added after the un-faded connections they over-write the unfaded connections.

[ewu63]

Something else to consider, it would be nice if the unfaded connections would come after the faded connections in the tikz file. Tiks works with layers so if faded connections are added after the un-faded connections they over-write the unfaded connections.

Yeah good point, this can also go into that finalize() function I mentioned.

[ewu63]

I fixed the faded process stuff. Some of the concerns are still not addressed but I don't think I will continue to work on this, so I think either someone else should take over this PR or we should merge as is and iterate later on for further improvements. @lamkina

[lamkina]

@nwu63 What are the remaining concerns? I can try and work on this if there's a demand for other features to be added/fixed.

[ewu63]

I've addressed everything on my end. However the logic is not super clean so it's up to the reviewers whether they think this is okay. I also did not address your concern with the ordering of the layers but that could be dealt with separately I think.

[eirikurj]

Whats the status on this? Are there any remaining concerns or changes that need to done?

[marcomangano]

I might remember incorrectly, but @lamkina wanted to make changes? Otw I can review this shortly

[lamkina]

I might remember incorrectly, but @lamkina wanted to make changes? Otw I can review this shortly

I think the changes I want to make may be better served for PR #52 or a different PR. I would check with @A-CGray if the changes he requested are good to go or not.

[A-CGray]

I think this is done from my perspective now, I implemented the change I requested a while back.

The behaviour of the auto fading is still not perfect because there are often multiple connections/inputs/outputs drawn on top of each other. To be sure of getting the intended fading you probably need to do all the fading manually but the auto_fade is still a nice first option.

[A-CGray]

@lamkina or @marcomangano can you review my latest changes and then merge if you're happy

[lamkina]

I added logic to fix fading the connections in the tikz figure so I think this is ready to merge now.