Spherical plotting of EBSD master pattern

hakonanes commented 2 years ago

Description of the change

This adds spherical plotting of EBSD master patterns using PyVista. This is the first of many PRs to kikuchipy that uses PyVista, which is a great tool for 3D plotting!

This introduces a new dependency on PyVista. The tests also depend on the panel package for interactive plotting, which I hope should work as in the PyVista documentation.

Progress of the PR

[x] Docstrings for all functions
[x] Unit tests with pytest for all lines
[x] Clean code style by running black via pre-commit

Minimal example of the bug fix or new feature

>>> import kikuchipy as kp
>>> mp = kp.data.nickel_ebsd_master_pattern(projection="stereographic")
>>> mp.plot_spherical(style="points")

See the docs for an interactive version of this plot (without axes and colorbar)!

For reviewers

[ ] The PR title is short, concise, and will make sense 1 year later.
[ ] New functions are imported in corresponding __init__.py.
[ ] New features, API changes, and deprecations are mentioned in the unreleased section in CHANGELOG.rst.
[ ] New contributors are added to .all-contributorsrc and the table is regenerated.

hakonanes commented 2 years ago

Two issues with the tests:

Lack of display option makes the newly added test fail on Ubuntu and Windows. PyVista seems to fix this by wrapping the pytest call with xfvb-run on Ubuntu, and using their custom action on Windows.
pyvista from PyPI cannot be installed with Python 3.10 due to vtk not being available from PyPI for Python 3.10, see this issue and this discussion for details. According to the issue, vtk will hopefully become available on PyPI for 3.10 this month.

hakonanes commented 2 years ago

I'll leave this PR until vtk is available for Python 3.10 from PyPI.

hakonanes commented 2 years ago

I'm temporarily closing this so that checks are only run in my fork.

hakonanes commented 2 years ago

According to this VTK Discourse thread, vtk v9.2.0 with Python 3.10 support will be released in the next few days... I think waiting for that instead of making 3D plotting optional is the way to go.

hakonanes commented 2 years ago

Making pyvista an optional dependency via an extra named "viz", as in pip install kikuchipy[viz], should work. Users on Python 3.10 who wants this feature can then install vtk via conda-forge and then kikuchipy[viz], or install pyvista as described here.

pyxem / kikuchipy