Add volume clipper

[akaszynski]

Add a volume clipper widget.

import numpy as np
import pyvista as pv

grid = pv.UniformGrid(dimensions=(200, 200, 200))
grid['scalars'] = np.linalg.norm(grid.center - grid.points, axis=1)
opacity = np.zeros(100)
opacity[::10] = np.geomspace(0.01, 0.75, 10)

pl = pv.Plotter()
pl.add_volume_clip_plane(grid, normal='-x', opacity=opacity[::-1], cmap='magma')
pl.show()

Bonus Modifications

• Change event_type to interaction_event for consistency.
• Consistently accept strings in interaction_event everywhere.

[codecov]

Codecov Report

Merging #3834 (568ba79) into main (bf670b6) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #3834      +/-   ##
==========================================
+ Coverage   94.13%   94.16%   +0.02%     
==========================================
  Files          87       87              
  Lines       19111    19125      +14     
==========================================
+ Hits        17991    18009      +18     
+ Misses       1120     1116       -4     

[banesullivan]

This looks really nice and I appreciate the clean up to the interaction events here