Pyside2 Example Error

[pyvista]

Pyside2 Example Error

[nicobako]

Hey, I would recommend reviewing #67 . I think you're having the same issue. If so, sorry, it's absolutely my fault.

[lmarschall]

thank you for the fast response, so i used the pip install command provided in the issue, but my version seem not be changed, and there fore the error still occurs...

[nicobako]

I'll look into this (hopefully) tomorrow and see if I can figure out what's going on.

[nicobako]

@lmarschall, change your code to the following and you should be all good to go:

import os
import sys

os.environ["QT_API"] = "pyside2"

# note import `qtpy` objects instead of `PySide2` objects
from qtpy import QtWidgets
from qtpy.QtWidgets import QMainWindow

# note placement of `import vtkmodules.qt after importing qtpy stuff
import vtkmodules.qt

import numpy as np

import pyvista as pv
from pyvistaqt import QtInteractor

class MainWindow(QMainWindow):

    def __init__(self, parent=None, show=True):
        QtWidgets.QMainWindow.__init__(self, parent)

        # create the frame
        self.frame = QtWidgets.QFrame()
        vlayout = QtWidgets.QVBoxLayout()

        # add the pyvista interactor object
        self.plotter = QtInteractor(self.frame)
        vlayout.addWidget(self.plotter.interactor)

        self.frame.setLayout(vlayout)
        self.setCentralWidget(self.frame)

        # simple menu to demo functions
        mainMenu = self.menuBar()
        fileMenu = mainMenu.addMenu('File')
        exitButton = QtWidgets.QAction('Exit', self)
        exitButton.setShortcut('Ctrl+Q')
        exitButton.triggered.connect(self.close)
        fileMenu.addAction(exitButton)

        # allow adding a sphere
        meshMenu = mainMenu.addMenu('Mesh')
        self.add_sphere_action = QtWidgets.QAction('Add Sphere', self)
        self.add_sphere_action.triggered.connect(self.add_sphere)
        meshMenu.addAction(self.add_sphere_action)

        if show:
            self.show()

    def add_sphere(self):
        """ add a sphere to the pyqt frame """
        sphere = pv.Sphere()
        self.plotter.add_mesh(sphere, show_edges=True)
        self.plotter.reset_camera()

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    window = MainWindow()
    sys.exit(app.exec_())

You'll see that the biggest difference is where I import vtkmodules.qt. This must be done after you have imported the qtpy stuff. This is because qtpy performs some really crazy stuff for making sure that everything is set up properly for the Qt bindings that you want to use. When you do this:

import vtkmodules.qt

os.environ["QT_API"] = "pyside2"

from qtpy import QtWidgets
from qtpy.QtWidgets import QMainWindow
...

you don't give qtpy time to setup the Qt bindings for PySide2 properly. Instead, you have handed that task to vtkmodules, which obviously has made assumptions about the Qt bindings that don't agree with what you are trying to do. For example, note that this works:

import vtkmodules.qt

os.environ["QT_API"] = "pyqt5"

from qtpy import QtWidgets
from qtpy.QtWidgets import QMainWindow

meaning that vtkmodules assumes pyqt5 as its default Qt Bindings, not PySide2...

The other really important thing to note is that I don't import PySide2 directly. Instead, I import qtpy objects. I may be completely wrong, but one of the benefits of using qtpy is that end users could decide to use pyqt5 or pyside2 at any point just by changing the QT_API environment variable... it's up to them. In this case, you are the end user. When you import PySide2 objects you circumvent qtpy's setup process, and make it impossible for end users to use qtpy to its fullest. I may be completely wrong here - I'm not a GUI developer nor a hardcore Qt user - but I think you should use the qtpy objects instead.

I hope this helps. Please let me know if you have any other questions, or if things are still not working for you.

[lmarschall]

hey nicobako,

i took your code and executed it with the following environment, unfortunately there's another error now :(

my environment:
python: 3.6.7
pyside2: 5.13.2
pyqt: 5.12.3
pyvista: 0.27.2
pyvistaqt: 0.2.0
qt: 5.12.9
qtpy: 1.9.0

my current error:

# add the pyvista interactor object
self.plotter = QtInteractor(self.frame)
QtInteractor cannot be converted to PyQt5.QtCore.QObject in this context

[nicobako]

Your error message says it's trying to convert it to a pyqt5 object. Either you're not running the code as written, or you still have not pip installed the master branch of pyvistaqt. The qtpy functionality is currently only available from the master branch of the GitHub repository. Try uninstalling pyvistaqt, then reinstalling it from the master branch following the directions in #67.

[lmarschall]

It works!

Sorry for the last error, that was me getting confused with all my testing environments. Finally i can proceed, thank you so much!
Maybe one last question, is there a plan to integrate qml view support into pyvistaqt?

[nicobako]

I don't know anything about qml view... That's a question for the core developpers of pyvistaqt.

[nicobako]

@lmarschall , do you feel comfortable closing this issue? Is your initial question resolved? If so, you can go ahead and close it yourself. Thanks!