Custom widget interaction events

[banesullivan]

Overview

Resolves #2455 by enabling users to specify custom interaction events for triggering the callbacks associated with widgets

cc @tomazbregar, please review if you have the opportunity

Example

Using vtk.vtkCommand.InteractionEvent

import numpy as np
from scipy.interpolate import griddata
import vtk
import pyvista as pv


def get_colors(n):
    """A helper function to get n colors"""
    from itertools import cycle

    import matplotlib

    cycler = matplotlib.rcParams['axes.prop_cycle']
    colors = cycle(cycler)
    colors = [next(colors)['color'] for i in range(n)]
    return colors


# Create a grid to interpolate to
xmin, xmax, ymin, ymax = 0, 100, 0, 100
x = np.linspace(xmin, xmax, num=25)
y = np.linspace(ymin, ymax, num=25)
xx, yy, zz = np.meshgrid(x, y, [0])

# Make sure boundary conditions exist
boundaries = np.array([[xmin, ymin, 0], [xmin, ymax, 0], [xmax, ymin, 0], [xmax, ymax, 0]])

# Create the PyVista mesh to hold this grid
surf = pv.StructuredGrid(xx, yy, zz)

# Create some initial perturbations
# - this array will be updated inplace
points = np.array([[33, 25, 45], [70, 80, 13], [51, 57, 10], [25, 69, 20]])


# Create an interpolation function to update that surface mesh
def update_surface(point, i):
    points[i] = point
    tp = np.vstack((points, boundaries))
    zz = griddata(tp[:, 0:2], tp[:, 2], (xx[:, :, 0], yy[:, :, 0]), method='cubic')
    surf.points[:, -1] = zz.ravel(order='F')
    return


# Get a list of unique colors for each widget
colors = get_colors(len(points))

# Begin the plotting routine
p = pv.Plotter(notebook=0)

# Add the surface to the scene
p.add_mesh(surf, color=True)

# Add the widgets which will update the surface
p.add_sphere_widget(update_surface, center=points, color=colors, radius=3, interaction_event=vtk.vtkCommand.InteractionEvent)
# Add axes grid
p.show_grid()

# Show it!
p.show()

[codecov]

Codecov Report

Merging #2882 (4e0307c) into main (5c230a2) will decrease coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #2882      +/-   ##
==========================================
- Coverage   94.11%   94.06%   -0.05%     
==========================================
  Files          76       76              
  Lines       16506    16506              
==========================================
- Hits        15535    15527       -8     
- Misses        971      979       +8     

[akaszynski]

Would be great if we can add this example here as well (probably a gallery example).

[banesullivan]

The example given above is pulled straight from the example gallery. Only difference is using the new param:

p.add_sphere_widget(..., interaction_event=vtk.vtkCommand.InteractionEvent)

Should we update a few of those examples in the gallery to use this param? Would need to update the screen captures as well

[akaszynski]

Should we update a few of those examples in the gallery to use this param? Would need to update the screen captures as well

Maybe just one if it's not too much work.

[banesullivan]

I added a demo of the custom interaction event to the slicing example -- that was the simplest and the concept/result is the same for all examples

[akaszynski]

LGTM. Thanks!

[banesullivan]

In the docstrings, I annotated the type as vtk.vtkCommand, but they are really vtk.vtkCommand.EventIds

>>> type(vtk.vtkCommand.EndInteractionEvent)
<class 'vtkCommonCorePython.vtkCommand.EventIds'>

[akaszynski]

Still LGTM.

[banesullivan]

@akaszynski and @tkoyama010, Will this automatically merge in 24 hours if no further action is taken?

[akaszynski]

@akaszynski and @tkoyama010, Will this automatically merge in 24 hours if no further action is taken?

I wish. We could probably create a GitHub action cron job that merges approved PRs after they've been open for 24H, but for now I've been doing it manually at the 24H+ mark.

[banesullivan]

Good enough for me - no rush here

[akaszynski]

Review removed due to merge with main, but merge was trivial.

Going to bypass 24H rule.