Plotting wrappers: Head Trajectory

[stellaprins]

Description

What is this PR

• Bug fix
• Addition of a new feature
• Other

Why is this PR needed?
To conveniently plot results with a single line of code.

What does this PR do?
Introduces a plot module with a trajectory function.

References

#387

How has this PR been tested?

Checked the updated documentation locally.

Is this a breaking change?

No.

Does this PR require an update to the documentation?

Yes. I've updated the first part of the Express 2D vectors in polar coordinates example.

Checklist:

• The code has been tested locally
• Tests have been added to cover all new functionality
• The documentation has been updated to reflect any changes
• The code has been formatted with pre-commit

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.81%. Comparing base (df4b4b1) to head (15dccd0).
Report is 3 commits behind head on main.

Additional details and impacted files

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  Coverage   99.80%   99.81%           
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  Files          14       16    +2     
  Lines        1025     1080   +55     
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+ Hits         1023     1078   +55     
  Misses          2        2           

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[willGraham01]

Some stylistic comments here from me.

As for testing, I'll copy what I put in our chat here so it's visible for everyone:

You can't really test "images" per se, so I'd follow the advice of the StackOverflow hive mind like in this article here: use trajectory to create a figure on some (small) custom dataset, then examine the data stored in the returned Figure object.

Maybe make a DataArray with 3 keypoints (left, centre, and right) that all move in parallel lines, with centre being the midpoint of the other two.
Then you can check that if you pass the left and right keypoints, the figure contains data that matches the centre points? Likewise you can also check that if you only pass one of the keypoints, the data in the returned plot matches the raw data for that keypoint?

[stellaprins]

Maybe make a DataArray with 3 keypoints (left, centre, and right) that all move in parallel lines, with centre being the midpoint of the other two. Then you can check that if you pass the left and right keypoints, the figure contains data that matches the centre points? Likewise you can also check that if you only pass one of the keypoints, the data in the returned plot matches the raw data for that keypoint?

May be able to use some of the valid_poses_dataset_ fixtures that have left, right, and centroid keypoints.

[willGraham01]

May be able to use some of the valid_poses_dataset_ fixtures that have left, right, and centroid keypoints.

Possibly, if they're simple enough to compute and work with then definitely re-use them.

My original idea was something like 3 "parallel lines" for the keypoints:

left: (-1,0) -> (-1,1) -> (-1,2) -> (-1,3) -> (-1,4)
centre: (0,0) -> (0,1) -> (0,2) -> (0,3) -> (0,4)
right: (1,0) -> (1,1) -> (1,2) -> (1,3) -> (1,4)

but if something like this already exists then go with that!