`BackgroundPlotter` frozen display

[fosskers]

Hi. I can't seem to get BackgroundPlotter to work as advertised.

    p = qt.BackgroundPlotter()
    p.add_mesh(mesh)

This should work, but instead opens a somewhat broken window that isn't interactive at all. On X11, I at least see one frame of output identical to what Plotter would output, although the content of its window is surrounded by a copy of the content of the terminal that spawned it. On Wayland, no initial frame appears, and the window is just filled with a slice of the terminal image.

Internet searches revealed that p.app.exec_() can get around this, and it does. The mesh renders, and the Qt window appears as we expect with a menu, etc. q works to quit, and I can drag around and zoom the mesh. However, this blocks the main thread, which is precisely what BackgroundPlotter is supposed to get around.

This occurs with all of pyqt5, pyqt6, and pyside6, on both Ubuntu 22 and 24.

Any idea what's happening here?

• pyvista 0.45.2
• pyvistaqt 0.11.2

[fosskers]

Probably not related, but I was also looking at #445