VisPy does not work properly if QtWebEngineWidgets is imported

[astrofrog]

I am trying to use vispy with PyQt 6.4 in an application where I also need to use QtWebEngineWidgets. This used to work fine with PyQt5 but no longer works. For example if I take the line_plot3d.py script from the examples in vispy:

import numpy as np
import sys

from vispy import app, visuals, scene

# build visuals
Plot3D = scene.visuals.create_visual_node(visuals.LinePlotVisual)

# build canvas
canvas = scene.SceneCanvas(keys='interactive', title='plot3d', show=True)

# Add a ViewBox to let the user zoom/rotate
view = canvas.central_widget.add_view()
view.camera = 'turntable'
view.camera.fov = 45
view.camera.distance = 6

# prepare data
N = 60
x = np.sin(np.linspace(-2, 2, N)*np.pi)
y = np.cos(np.linspace(-2, 2, N)*np.pi)
z = np.linspace(-2, 2, N)

# plot
pos = np.c_[x, y, z]
Plot3D(pos, width=2.0, color='red',
       edge_color='w', symbol='o', face_color=(0.2, 0.2, 1, 0.8),
       parent=view.scene)


if __name__ == '__main__':
    if sys.flags.interactive != 1:
        app.run()

I get:

So far, so good. However, if I add an import at the top:

from qtpy import QtWebEngineWidgets  # ADDED IMPORT

import numpy as np
import sys

from vispy import app, visuals, scene

# build visuals
Plot3D = scene.visuals.create_visual_node(visuals.LinePlotVisual)

# build canvas
canvas = scene.SceneCanvas(keys='interactive', title='plot3d', show=True)

# Add a ViewBox to let the user zoom/rotate
view = canvas.central_widget.add_view()
view.camera = 'turntable'
view.camera.fov = 45
view.camera.distance = 6

# prepare data
N = 60
x = np.sin(np.linspace(-2, 2, N)*np.pi)
y = np.cos(np.linspace(-2, 2, N)*np.pi)
z = np.linspace(-2, 2, N)

# plot
pos = np.c_[x, y, z]
Plot3D(pos, width=2.0, color='red',
       edge_color='w', symbol='o', face_color=(0.2, 0.2, 1, 0.8),
       parent=view.scene)


if __name__ == '__main__':
    if sys.flags.interactive != 1:
        app.run()

Then the output is:

I am using the latest developer version of VisPy on Python 3.11.2 on an M1 Mac.

[djhoese]

I've seen this in the past with one of the various incarnations of web-widgets in the Qt space and older version of Qt (maybe 5.x). As best I remember this is usually a bug in Qt with interactions between the OpenGL widgets and the web engine widgets.

Edit: Otherwise #2570 so I won't have time for debugging this further.

[aganders3]

@astrofrog can you post your whole env (print(vispy.sys_info())? I can't reproduce this with Python 3.11.4 + PyQt 6.6 on an M1 Mac.

[astrofrog]

@aganders3 - ah this works for me too on 6.6, it didn't work on 6.4, so maybe this was indeed a Qt6 bug that has been fixed?

[aganders3]

That's great @astrofrog - maybe look for a Qt bug but otherwise can you close this issue if you're satisfied?