Problem when using QGLWidget

[wmvanvliet]

When setting QVTKRWIBase = "QGLWidget" in vtkmodules/qt/__init__.py to work around rendering glitches, no graphics are being shown and the following error is generated:

QPainter::begin: Paint device returned engine == 0, type: 1

In tvtk/pyface/ui/qt4/QVTKRenderWindowInteractor.py, there is the following construct:

if PyQtImpl == "PyQt5":
    if QVTKRWIBase == "QGLWidget":
        try:
            from PyQt5.QtWidgets import QOpenGLWidget as QGLWidget
        except:
            from PyQt5.QtOpenGL import QGLWidget

Removing the try/catch black to force using the deprecated QGLWidget instead of the more modern QOpenGLWidget fixes the problem and everything runs smoothly. However, we should of course use QOpenGLWidget. But there must be some difference between the two that is causing the error.

I tested this on multiple devices with different types of video cards, I consistently get the error every time.

@larsoner

[larsoner]

The upstream version of this code does not appear to use QOpenGLWidget at all:

https://gitlab.kitware.com/vtk/vtk/blob/741fffbf6490c34228dfe437f330d854b2494adc/Wrapping/Python/vtkmodules/qt/QVTKRenderWindowInteractor.py#L77

I have no idea why this is the case. The Mayavi code looks a lot like the upstream code, but there are some differences (such as this one).

I can replicate the problem with this code:

>>> import vtk.qt
>>> vtk.qt.QVTKRWIBase
'QWidget'
>>> vtkmodules.qt.QVTKRWIBase = "QGLWidget"
>>> from mayavi import mlab
>>> mlab.test_plot3d()
QPainter::begin: Paint device returned engine == 0, type: 1

So this does appear to be a legitimate bug, assuming we are supposed to be allowed to set this value. @prabhuramachandran it looks like you added this in https://github.com/enthought/mayavi/commit/36d4bd7cf95b60df53584a21add019af44a0c2b7 / https://github.com/enthought/mayavi/pull/528. Any chance you remember testing this mode or not?

Also possibly related to this:

https://github.com/pyvista/pyvista/pull/498 https://github.com/pyvista/pyvista/issues/473 https://gitlab.kitware.com/vtk/vtk/-/issues/17867 https://discourse.vtk.org/t/vtk-9-pyqt-macos-no-rendering/3358/6

I still don't really understand how these things are supposed to work. :( It will take some reading to figure it out -- no time right now for me to do it but maybe in a few weeks.

[adam-grant-hendry]

@larsoner After debugging in VSCode with the following launch.json so it will go into packages:

{
    "configurations": [
        {
            "name": "Python: Current File",
            "type": "python",
            "request": "launch",
            "program": "${file}",
            "console": "integratedTerminal",
            "justMyCode": false
        }
    ],
}

the culprit is rwi.py::QVTKRenderWindowInteractor.paintEngine() getting called when a Paint event occurs:

def paintEngine(self):
    return None

From the PySide6 QPaintEngine docs (it has nearly 2 years since the OP posted the issue and PySide6 is now supported),

• type 0 is X11 (QPaintEngine.X11 == 0)
• type 1 is Windows (QPaintEngine.Windows == 1)

My guess is paintEngine was overriden to return None (NULL in C++) to avoid the error:

QWidget::paintEngine: Should no longer be called

since when the paintEngine method is removed from QVTKRenderWindowInteractor, this happens.

[adam-grant-hendry]

@larsoner @wmvanvliet Linking also to pyvistaqt discussion QPainter::begin: Paint device returned engine == 0, type: 1.

The culprit appears to be QVTKRenderWindowInteractor.paintEngine()

[adam-grant-hendry]

@larsoner @wmvanvliet The following widget attribute is set in pyvistaqt.rwi::QVTKRenderWindowInteractor.__init__():

self.setAttribute(WidgetAttribute.WA_PaintOnScreen)

The PySide6.QtCore.Qt docs state this attribute is only available in X11 and I think paintEngine() was set to return None (NULL) on purpose for X11 systems:

Hence this clearly causes a problem on non-X11 systems. An alternative is required for non-X11 systems.

[adam-grant-hendry]

@larsoner @wmvanvliet If either of you are attending SciPy this year, it might be a good opportunity to debug this in a sprint session (July 16-17).

I, unfortunately, will be away on vacation, but since it starts tomorrow and most of the developer community will be there, it would be a good opportunity to debug this.

[adam-grant-hendry]

Linking as well the VTK issue I posted for this: QPainter::begin: Paint device returned engine == 0, type: 1 #18606

[prabhuramachandran]

I am around at SciPy this year and will be here for the sprints too. I am planning on pushing a quick release soon though before the tutorials.

[prabhuramachandran]

The upstream version of this code does not appear to use QOpenGLWidget at all:

So this does appear to be a legitimate bug, assuming we are supposed to be allowed to set this value. @prabhuramachandran it looks like you added this in 36d4bd7 / #528. Any chance you remember testing this mode or not?

Unfortunately I do not remember. I suspect I just pulled over code changes from VTK and added them into the Mayavi version which has diverged a bit from VTK. The problem for me of course is that we need to support different VTK versions. I need to revisit the Mayavi version.

[wmvanvliet]

@larsoner @wmvanvliet If either of you are attending SciPy this year, it might be a good opportunity to debug this in a sprint session (July 16-17).

I should start attending SciPy... Anyway, great to see this old thread being dug up. If this bug could be fixed, that would finally allow us to comfortably use non-nVidia graphic cards with mayavi.

[prabhuramachandran]

I intend to put out a release fixing some other issues today but can address this by end of SciPy. My time is extremely limited right now as I rush to prepare for a couple of tutorials, it would really help me if you could summarize how I can reproduce the problem on a conda environment (right now I am on a linux laptop but do have an nvidia card), then I could debug the issue and implement a fix. Some details on what OS and hardware you are looking at would help.

[prabhuramachandran]

If this is just a matter of merging with upstream VTK changes (https://gitlab.kitware.com/vtk/vtk/-/merge_requests/9048) then that makes my life easy too. Thanks. Please let me know.

[wmvanvliet]

@larsoner Posted a minimum example to demonstrate the issue in the second comment in this tread ^^

[wmvanvliet]

Merging the upstream VTK changes might solve the issue already.

[adam-grant-hendry]

@prabhuramachandran @wmvanvliet Thank you for your help!

I am available today and tomorrow, should you need any help testing on a Windows 10 machine with an NVIDIA graphics card.

[adam-grant-hendry]

BTW, @prabhuramachandran , I was scratching my head trying to remember where I had seen you before, and then your SciPy 2018 presentation popped up!

3D Visualization with Mayavi | SciPy 2018 Tutorial | Prabhu Ramachandran

Thanks for the great tutorials!

[prabhuramachandran]

@prabhuramachandran @wmvanvliet Thank you for your help!

I am available today and tomorrow, should you need any help testing on a Windows 10 machine with an NVIDIA graphics card.

Unfortunately, I am swamped today and tomorrow, (I have two tutorials which I am teaching and need to work on the content) we could try tomorrow evening after the back to back tutorials but I will probably be pretty dead by then. I am here all week and also at the sprints. It would be awesome to have this resolved by the end of the conference. Many thanks for offering to help with this, it is much appreciated.

[prabhuramachandran]

FWIW, pushed a 4.8.0 release just now, will roll the fix for this in the next one.

[adam-grant-hendry]

@prabhuramachandran @wmvanvliet Would I be able to join a sprint via Zoom? I will be in Tahoe with limited Internet connectivity and I'm unsure what my family schedule will be, but I can certainly try to join. Do either of you have a time in mind?

Regardless, I will attempt to provide whatever assistance I can within comments here. This is still fairly new territory for me, so please take any potential "fixes" here with a grain of salt (of course, would be FANTASTIC to follow up with some good unit tests, esp. for regressions).

1. The pyvistaqt repo already has pulled in the vtk upstream changes, but the problem persists (at least on my machine). You can find pyvistaqt's variation of QVTKRenderWindowInteractor here: pyvistaqt/rwi.py

2. Considering WA_PaintOnScreen is claimed only to work for X11, I modified (the pyvistaqt) rwi.py slightly to:

...
59: import os
...
373: if os.name == 'posix':
374:     self.setAttribute(WidgetAttribute.WA_PaintOnScreen)

Re-running my MRE:

from pyvistaqt import MainWindow, QtInteractor
from qtpy import QtWidgets

class Window(MainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Example')

        self.layout_ = QtWidgets.QVBoxLayout()

        self.container = QtWidgets.QFrame()
        self.container.setLayout(self.layout_)
        self.setCentralWidget(self.container)

        self.plotter = QtInteractor(parent=self.container)
        self.layout_.addWidget(self.plotter)
        self.plotter.show()

        self.signal_close.connect(self.plotter.close)


app = QtWidgets.QApplication([])
window = Window()
window.show()
app.exec_()

gives the following error:

QWindowsGLContext::makeCurrent: SetPixelFormat() failed (The pixel format is invalid.)
qt.qpa.backingstore: composeAndFlush: makeCurrent() failed

which tells me Qt isn't picking up on the fact that we are trying to use OpenGL. From the PySide6 QBackingStore docs:

QBackingStore enables the use of QPainter to paint on a QWindow with type RasterSurface. The other way of rendering to a QWindow is through the use of OpenGL with QOpenGLContext .

A QBackingStore contains a buffered representation of the window contents, and thus supports partial updates by using QPainter to only update a sub region of the window contents.

QBackingStore might be used by an application that wants to use QPainter without OpenGL acceleration and without the extra overhead of using the QWidget or QGraphicsView UI stacks. For an example of how to use QBackingStore see the Raster Window Example .

Indeed, PySide provides an example of how to pull Context Info from the running program. NOTE: This would be good to leverage for future unit tests.

If I change rwi.py to the following:

rwi.py

modified from: https://gitlab.kitware.com/vtk/vtk

under the OSI-approved BSD 3-clause License

TODO: Mayavi has a potentially different version that might be better or worse

coding=utf-8

""" A simple VTK widget for PyQt or PySide. See http://www.trolltech.com for Qt documentation, http://www.riverbankcomputing.co.uk for PyQt, and http://pyside.github.io for PySide.

This class is based on the vtkGenericRenderWindowInteractor and is therefore fairly powerful. It should also play nicely with the vtk3DWidget code.

Created by Prabhu Ramachandran, May 2002 Based on David Gobbi's QVTKRenderWidget.py

Changes by Gerard Vermeulen Feb. 2003 Win32 support.

Changes by Gerard Vermeulen, May 2003 Bug fixes and better integration with the Qt framework.

Changes by Phil Thompson, Nov. 2006 Ported to PyQt v4. Added support for wheel events.

Changes by Phil Thompson, Oct. 2007 Bug fixes.

Changes by Phil Thompson, Mar. 2008 Added cursor support.

Changes by Rodrigo Mologni, Sep. 2013 (Credit to Daniele Esposti) Bug fix to PySide: Converts PyCObject to void pointer.

Changes by Greg Schussman, Aug. 2014 The keyPressEvent function now passes keysym instead of None.

Changes by Alex Tsui, Apr. 2015 Port from PyQt4 to PyQt5.

Changes by Fabian Wenzel, Jan. 2016 Support for Python3

Changes by Tobias Hänel, Sep. 2018 Support for PySide2

Changes by Ruben de Bruin, Aug. 2019 Fixes to the keyPressEvent function

Changes by Chen Jintao, Aug. 2021 Support for PySide6

Changes by Eric Larson and Guillaume Favelier, Apr. 2022 Support for PyQt6 """

import os import sys

Check whether a specific PyQt implementation was chosen

try: import vtkmodules.qt

PyQtImpl = vtkmodules.qt.PyQtImpl

except ImportError: pass

Check whether a specific QVTKRenderWindowInteractor base

class was chosen, can be set to "QGLWidget" in

PyQt implementation version lower than Pyside6,

or "QOpenGLWidget" in Pyside6

QVTKRWIBase = "QWidget" try: import vtkmodules.qt

QVTKRWIBase = vtkmodules.qt.QVTKRWIBase

except ImportError: pass

from vtkmodules.vtkRenderingCore import vtkRenderWindow from vtkmodules.vtkRenderingUI import vtkGenericRenderWindowInteractor

if PyQtImpl is None: # Autodetect the PyQt implementation to use try: import PyQt6

    PyQtImpl = "PyQt6"
except ImportError:
    try:
        import PySide6

        PyQtImpl = "PySide6"
    except ImportError:
        try:
            import PyQt5

            PyQtImpl = "PyQt5"
        except ImportError:
            try:
                import PySide2

                PyQtImpl = "PySide2"
            except ImportError:
                try:
                    import PyQt4

                    PyQtImpl = "PyQt4"
                except ImportError:
                    try:
                        import PySide

                        PyQtImpl = "PySide"
                    except ImportError:
                        raise ImportError("Cannot load either PyQt or PySide")

Check the compatibility of PyQtImpl and QVTKRWIBase

if QVTKRWIBase != "QWidget": if PyQtImpl in ["PyQt6", "PySide6"] and QVTKRWIBase == "QOpenGLWidget": pass # compatible elif ( PyQtImpl in ["PyQt5", "PySide2", "PyQt4", "PySide"] and QVTKRWIBase == "QGLWidget" ): pass # compatible else: raise ImportError("Cannot load " + QVTKRWIBase + " from " + PyQtImpl)

if PyQtImpl == "PyQt6": if QVTKRWIBase == "QOpenGLWidget": from PyQt6.QtOpenGLWidgets import QOpenGLWidget from PyQt6.QtCore import QEvent, QObject, QSize, Qt, QTimer from PyQt6.QtGui import QCursor from PyQt6.QtWidgets import QApplication, QMainWindow, QSizePolicy, QWidget elif PyQtImpl == "PySide6": if QVTKRWIBase == "QOpenGLWidget": from PySide6.QtOpenGLWidgets import QOpenGLWidget from PySide6.QtCore import QEvent, QLibraryInfo, QObject, QSize, Qt, QTimer from PySide6.QtGui import QCursor, QOpenGLContext, QSurfaceFormat, QWindow from PySide6.QtWidgets import ( QApplication, QMainWindow, QMessageBox, QSizePolicy, QWidget, ) elif PyQtImpl == "PyQt5": if QVTKRWIBase == "QGLWidget": from PyQt5.QtOpenGL import QGLWidget from PyQt5.QtCore import QEvent, QObject, QSize, Qt, QTimer from PyQt5.QtGui import QCursor from PyQt5.QtWidgets import QApplication, QMainWindow, QSizePolicy, QWidget elif PyQtImpl == "PySide2": if QVTKRWIBase == "QGLWidget": from PySide2.QtOpenGL import QGLWidget from PySide2.QtCore import QEvent, QObject, QSize, Qt, QTimer from PySide2.QtGui import QCursor from PySide2.QtWidgets import QApplication, QMainWindow, QSizePolicy, QWidget elif PyQtImpl == "PyQt4": if QVTKRWIBase == "QGLWidget": from PyQt4.QtOpenGL import QGLWidget from PyQt4.QtCore import QEvent, QObject, QSize, Qt, QTimer from PyQt4.QtGui import QApplication, QMainWindow, QSizePolicy, QWidget elif PyQtImpl == "PySide": if QVTKRWIBase == "QGLWidget": from PySide.QtOpenGL import QGLWidget from PySide.QtCore import QEvent, QObject, QSize, Qt, QTimer from PySide.QtGui import QApplication, QMainWindow, QSizePolicy, QWidget else: raise ImportError("Unknown PyQt implementation " + repr(PyQtImpl))

Define types for base class, based on string

if QVTKRWIBase == "QWidget": QVTKRWIBaseClass = QWidget elif QVTKRWIBase == "QGLWidget": QVTKRWIBaseClass = QGLWidget elif QVTKRWIBase == "QOpenGLWidget": QVTKRWIBaseClass = QOpenGLWidget else: raise ImportError("Unknown base class for QVTKRenderWindowInteractor " + QVTKRWIBase)

if PyQtImpl == 'PyQt6': CursorShape = Qt.CursorShape MouseButton = Qt.MouseButton WindowType = Qt.WindowType WidgetAttribute = Qt.WidgetAttribute KeyboardModifier = Qt.KeyboardModifier FocusPolicy = Qt.FocusPolicy ConnectionType = Qt.ConnectionType Key = Qt.Key SizePolicy = QSizePolicy.Policy EventType = QEvent.Type else: CursorShape = ( MouseButton ) = ( WindowType ) = WidgetAttribute = KeyboardModifier = FocusPolicy = ConnectionType = Key = Qt SizePolicy = QSizePolicy EventType = QEvent

if PyQtImpl in ('PyQt4', 'PySide'): MiddleButton = MouseButton.MidButton else: MiddleButton = MouseButton.MiddleButton

try: from OpenGL import GL except ImportError: app = QApplication(sys.argv) message_box = QMessageBox( QMessageBox.Critical, "ContextInfo", "PyOpenGL must be installed to run this example.", QMessageBox.Close, ) message_box.setDetailedText("Run:\npip install PyOpenGL PyOpenGL_accelerate") message_box.exec() sys.exit(1)

def _get_event_pos(ev): try: # Qt6+ return ev.position().x(), ev.position().y() except AttributeError: # Qt5 return ev.x(), ev.y()

def print_surface_format(surface_format): profile_name = ( 'core' if surface_format.profile() == QSurfaceFormat.CoreProfile else 'compatibility' ) major = surface_format.majorVersion() minor = surface_format.minorVersion() return f"{profile_name} version {major}.{minor}"

class QVTKRenderWindowInteractor(QVTKRWIBaseClass):

"""A QVTKRenderWindowInteractor for Python and Qt.  Uses a
vtkGenericRenderWindowInteractor to handle the interactions.  Use
GetRenderWindow() to get the vtkRenderWindow.  Create with the
keyword stereo=1 in order to generate a stereo-capable window.

The user interface is summarized in vtkInteractorStyle.h:

- Keypress j / Keypress t: toggle between joystick (position
sensitive) and trackball (motion sensitive) styles. In joystick
style, motion occurs continuously as long as a mouse button is
pressed. In trackball style, motion occurs when the mouse button
is pressed and the mouse pointer moves.

- Keypress c / Keypress o: toggle between camera and object
(actor) modes. In camera mode, mouse events affect the camera
position and focal point. In object mode, mouse events affect
the actor that is under the mouse pointer.

- Button 1: rotate the camera around its focal point (if camera
mode) or rotate the actor around its origin (if actor mode). The
rotation is in the direction defined from the center of the
renderer's viewport towards the mouse position. In joystick mode,
the magnitude of the rotation is determined by the distance the
mouse is from the center of the render window.

- Button 2: pan the camera (if camera mode) or translate the actor
(if object mode). In joystick mode, the direction of pan or
translation is from the center of the viewport towards the mouse
position. In trackball mode, the direction of motion is the
direction the mouse moves. (Note: with 2-button mice, pan is
defined as <Shift>-Button 1.)

- Button 3: zoom the camera (if camera mode) or scale the actor
(if object mode). Zoom in/increase scale if the mouse position is
in the top half of the viewport; zoom out/decrease scale if the
mouse position is in the bottom half. In joystick mode, the amount
of zoom is controlled by the distance of the mouse pointer from
the horizontal centerline of the window.

- Keypress 3: toggle the render window into and out of stereo
mode.  By default, red-blue stereo pairs are created. Some systems
support Crystal Eyes LCD stereo glasses; you have to invoke
SetStereoTypeToCrystalEyes() on the rendering window.  Note: to
use stereo you also need to pass a stereo=1 keyword argument to
the constructor.

- Keypress e: exit the application.

- Keypress f: fly to the picked point

- Keypress p: perform a pick operation. The render window interactor
has an internal instance of vtkCellPicker that it uses to pick.

- Keypress r: reset the camera view along the current view
direction. Centers the actors and moves the camera so that all actors
are visible.

- Keypress s: modify the representation of all actors so that they
are surfaces.

- Keypress u: invoke the user-defined function. Typically, this
keypress will bring up an interactor that you can type commands in.

- Keypress w: modify the representation of all actors so that they
are wireframe.
"""

# Map between VTK and Qt cursors.
_CURSOR_MAP = {
    0: CursorShape.ArrowCursor,  # VTK_CURSOR_DEFAULT
    1: CursorShape.ArrowCursor,  # VTK_CURSOR_ARROW
    2: CursorShape.SizeBDiagCursor,  # VTK_CURSOR_SIZENE
    3: CursorShape.SizeFDiagCursor,  # VTK_CURSOR_SIZENWSE
    4: CursorShape.SizeBDiagCursor,  # VTK_CURSOR_SIZESW
    5: CursorShape.SizeFDiagCursor,  # VTK_CURSOR_SIZESE
    6: CursorShape.SizeVerCursor,  # VTK_CURSOR_SIZENS
    7: CursorShape.SizeHorCursor,  # VTK_CURSOR_SIZEWE
    8: CursorShape.SizeAllCursor,  # VTK_CURSOR_SIZEALL
    9: CursorShape.PointingHandCursor,  # VTK_CURSOR_HAND
    10: CursorShape.CrossCursor,  # VTK_CURSOR_CROSSHAIR
}

def __init__(self, parent=None, **kw):
    # the current button
    self._ActiveButton = MouseButton.NoButton

    # private attributes
    self.__saveX = 0
    self.__saveY = 0
    self.__saveModifiers = KeyboardModifier.NoModifier
    self.__saveButtons = MouseButton.NoButton
    self.__wheelDelta = 0

    # do special handling of some keywords:
    # stereo, rw

    try:
        stereo = bool(kw['stereo'])
    except KeyError:
        stereo = False

    try:
        rw = kw['rw']
    except KeyError:
        rw = None

    # create base qt-level widget
    if QVTKRWIBase == "QWidget":
        if "wflags" in kw:
            wflags = kw['wflags']
        else:
            wflags = Qt.WindowType.Widget
        QWidget.__init__(self, parent, wflags | WindowType.MSWindowsOwnDC)
    elif QVTKRWIBase == "QGLWidget":
        QGLWidget.__init__(self, parent)
    elif QVTKRWIBase == "QOpenGLWidget":
        QOpenGLWidget.__init__(self, parent)

    if rw:  # user-supplied render window
        self._RenderWindow = rw
    else:
        self._RenderWindow = vtkRenderWindow()

    WId = self.winId()

    # Python2
    if type(WId).__name__ == 'PyCObject':
        from ctypes import c_void_p, py_object, pythonapi

        pythonapi.PyCObject_AsVoidPtr.restype = c_void_p
        pythonapi.PyCObject_AsVoidPtr.argtypes = [py_object]

        WId = pythonapi.PyCObject_AsVoidPtr(WId)

    # Python3
    elif type(WId).__name__ == 'PyCapsule':
        from ctypes import c_char_p, c_void_p, py_object, pythonapi

        pythonapi.PyCapsule_GetName.restype = c_char_p
        pythonapi.PyCapsule_GetName.argtypes = [py_object]

        name = pythonapi.PyCapsule_GetName(WId)

        pythonapi.PyCapsule_GetPointer.restype = c_void_p
        pythonapi.PyCapsule_GetPointer.argtypes = [py_object, c_char_p]

        WId = pythonapi.PyCapsule_GetPointer(WId, name)

    self._RenderWindow.SetWindowInfo(str(int(WId)))

    if stereo:  # stereo mode
        self._RenderWindow.StereoCapableWindowOn()
        self._RenderWindow.SetStereoTypeToCrystalEyes()

    try:
        self._Iren = kw['iren']
    except KeyError:
        self._Iren = vtkGenericRenderWindowInteractor()
        self._Iren.SetRenderWindow(self._RenderWindow)

    # do all the necessary qt setup
    self.setAttribute(WidgetAttribute.WA_OpaquePaintEvent)
    if os.name == 'posix':
        self.setAttribute(WidgetAttribute.WA_PaintOnScreen)
    self.setMouseTracking(True)  # get all mouse events
    self.setFocusPolicy(FocusPolicy.WheelFocus)
    self.setSizePolicy(QSizePolicy(SizePolicy.Expanding, SizePolicy.Expanding))

    self._Timer = QTimer(self)
    self._Timer.timeout.connect(self.TimerEvent)

    self._Iren.AddObserver('CreateTimerEvent', self.CreateTimer)
    self._Iren.AddObserver('DestroyTimerEvent', self.DestroyTimer)
    self._Iren.GetRenderWindow().AddObserver(
        'CursorChangedEvent', self.CursorChangedEvent
    )

    # If we've a parent, it does not close the child when closed.
    # Connect the parent's destroyed signal to this widget's close
    # slot for proper cleanup of VTK objects.
    if self.parent():
        self.parent().destroyed.connect(self.close, ConnectionType.DirectConnection)

def glInfo(self):
    if not self.context.makeCurrent(self):
        raise Exception("makeCurrent() failed")
    functions = self.context.functions()
    gl_vendor = functions.glGetString(GL.GL_VENDOR)
    gl_renderer = functions.glGetString(GL.GL_RENDERER)
    gl_version = functions.glGetString(GL.GL_VERSION)
    gl_lang_version = functions.glGetString(GL.GL_SHADING_LANGUAGE_VERSION)
    context_surface_format = print_surface_format(self.context.format())
    surface_format = print_surface_format(self.format())

    text = (
        f"Vendor: {gl_vendor}\n"
        f"Renderer: {gl_renderer}\n"
        f"Version: {gl_version}\n"
        f"Shading language: {gl_lang_version}\n"
        f"Context Format: {context_surface_format}\n\n"
        f"Surface Format: {surface_format}"
    )
    self.context.doneCurrent()
    return text

def __getattr__(self, attr):
    """Makes the object behave like a vtkGenericRenderWindowInteractor"""
    if attr == '__vtk__':
        return lambda t=self._Iren: t
    elif hasattr(self._Iren, attr):
        return getattr(self._Iren, attr)
    else:
        raise AttributeError(
            self.__class__.__name__ + " has no attribute named " + attr
        )

def Finalize(self):
    '''
    Call internal cleanup method on VTK objects
    '''
    self._RenderWindow.Finalize()

def CreateTimer(self, obj, evt):
    self._Timer.start(10)

def DestroyTimer(self, obj, evt):
    self._Timer.stop()
    return 1

def TimerEvent(self):
    self._Iren.TimerEvent()

def CursorChangedEvent(self, obj, evt):
    """Called when the CursorChangedEvent fires on the render window."""
    # This indirection is needed since when the event fires, the current
    # cursor is not yet set so we defer this by which time the current
    # cursor should have been set.
    QTimer.singleShot(0, self.ShowCursor)

def HideCursor(self):
    """Hides the cursor."""
    self.setCursor(Qt.BlankCursor)

def ShowCursor(self):
    """Shows the cursor."""
    vtk_cursor = self._Iren.GetRenderWindow().GetCurrentCursor()
    qt_cursor = self._CURSOR_MAP.get(vtk_cursor, Qt.ArrowCursor)
    self.setCursor(qt_cursor)

def closeEvent(self, evt):
    self.Finalize()

def sizeHint(self):
    return QSize(400, 400)

def paintEngine(self):
    return None

def glInfo(self):
    build = QLibraryInfo.build()
    print(f'{build}\n\nPython {sys.version}')
    context = self.context()
    # if not context.makeCurrent(self):
    #     raise Exception("makeCurrent() failed")
    functions = context.functions()
    gl_vendor = functions.glGetString(GL.GL_VENDOR)
    gl_renderer = functions.glGetString(GL.GL_RENDERER)
    gl_version = functions.glGetString(GL.GL_VERSION)
    gl_lang_version = functions.glGetString(GL.GL_SHADING_LANGUAGE_VERSION)
    context_surface_format = print_surface_format(context.format())
    surface_format = print_surface_format(self.format())

    text = (
        f"Vendor: {gl_vendor}\n"
        f"Renderer: {gl_renderer}\n"
        f"Version: {gl_version}\n"
        f"Shading language: {gl_lang_version}\n"
        f"Context Format: {context_surface_format}\n\n"
        f"Surface Format: {surface_format}\n\n"
    )
    context.doneCurrent()
    print(text)

def paintEvent(self, ev):
    self.glInfo()
    self._Iren.Render()

def resizeEvent(self, ev):
    scale = self._getPixelRatio()
    w = int(round(scale * self.width()))
    h = int(round(scale * self.height()))
    self._RenderWindow.SetDPI(int(round(72 * scale)))
    vtkRenderWindow.SetSize(self._RenderWindow, w, h)
    self._Iren.SetSize(w, h)
    self._Iren.ConfigureEvent()
    self.update()

def _GetKeyCharAndKeySym(self, ev):
    """Convert a Qt key into a char and a vtk keysym.

    This is essentially copied from the c++ implementation in
    GUISupport/Qt/QVTKInteractorAdapter.cxx.
    """
    # if there is a char, convert its ASCII code to a VTK keysym
    try:
        keyChar = ev.text()[0]
        keySym = _keysyms_for_ascii[ord(keyChar)]
    except IndexError:
        keyChar = '\0'
        keySym = None

    # next, try converting Qt key code to a VTK keysym
    if keySym is None:
        try:
            keySym = _keysyms[ev.key()]
        except KeyError:
            keySym = None

    # use "None" as a fallback
    if keySym is None:
        keySym = "None"

    return keyChar, keySym

def _GetCtrlShift(self, ev):
    ctrl = shift = False

    if hasattr(ev, 'modifiers'):
        if ev.modifiers() & KeyboardModifier.ShiftModifier:
            shift = True
        if ev.modifiers() & KeyboardModifier.ControlModifier:
            ctrl = True
    else:
        if self.__saveModifiers & KeyboardModifier.ShiftModifier:
            shift = True
        if self.__saveModifiers & KeyboardModifier.ControlModifier:
            ctrl = True

    return ctrl, shift

@staticmethod
def _getPixelRatio():
    if PyQtImpl in ["PyQt5", "PySide2", "PySide6"]:
        # Source: https://stackoverflow.com/a/40053864/3388962
        pos = QCursor.pos()
        for screen in QApplication.screens():
            rect = screen.geometry()
            if rect.contains(pos):
                return screen.devicePixelRatio()
        # Should never happen, but try to find a good fallback.
        return QApplication.instance().devicePixelRatio()
    else:
        # Qt4 seems not to provide any cross-platform means to get the
        # pixel ratio.
        return 1.0

def _setEventInformation(self, x, y, ctrl, shift, key, repeat=0, keysum=None):
    scale = self._getPixelRatio()
    self._Iren.SetEventInformation(
        int(round(x * scale)),
        int(round((self.height() - y - 1) * scale)),
        ctrl,
        shift,
        key,
        repeat,
        keysum,
    )

def enterEvent(self, ev):
    ctrl, shift = self._GetCtrlShift(ev)
    self._setEventInformation(
        self.__saveX, self.__saveY, ctrl, shift, chr(0), 0, None
    )
    self._Iren.EnterEvent()

def leaveEvent(self, ev):
    ctrl, shift = self._GetCtrlShift(ev)
    self._setEventInformation(
        self.__saveX, self.__saveY, ctrl, shift, chr(0), 0, None
    )
    self._Iren.LeaveEvent()

def mousePressEvent(self, ev):
    pos_x, pos_y = _get_event_pos(ev)
    ctrl, shift = self._GetCtrlShift(ev)
    repeat = 0
    if ev.type() == EventType.MouseButtonDblClick:
        repeat = 1
    self._setEventInformation(pos_x, pos_y, ctrl, shift, chr(0), repeat, None)

    self._ActiveButton = ev.button()

    if self._ActiveButton == MouseButton.LeftButton:
        self._Iren.LeftButtonPressEvent()
    elif self._ActiveButton == MouseButton.RightButton:
        self._Iren.RightButtonPressEvent()
    elif self._ActiveButton == MiddleButton:
        self._Iren.MiddleButtonPressEvent()

def mouseReleaseEvent(self, ev):
    pos_x, pos_y = _get_event_pos(ev)
    ctrl, shift = self._GetCtrlShift(ev)
    self._setEventInformation(pos_x, pos_y, ctrl, shift, chr(0), 0, None)

    if self._ActiveButton == MouseButton.LeftButton:
        self._Iren.LeftButtonReleaseEvent()
    elif self._ActiveButton == MouseButton.RightButton:
        self._Iren.RightButtonReleaseEvent()
    elif self._ActiveButton == MiddleButton:
        self._Iren.MiddleButtonReleaseEvent()

def mouseMoveEvent(self, ev):
    pos_x, pos_y = _get_event_pos(ev)
    self.__saveModifiers = ev.modifiers()
    self.__saveButtons = ev.buttons()
    self.__saveX = pos_x
    self.__saveY = pos_y

    ctrl, shift = self._GetCtrlShift(ev)
    self._setEventInformation(pos_x, pos_y, ctrl, shift, chr(0), 0, None)
    self._Iren.MouseMoveEvent()

def keyPressEvent(self, ev):
    key, keySym = self._GetKeyCharAndKeySym(ev)
    ctrl, shift = self._GetCtrlShift(ev)
    self._setEventInformation(self.__saveX, self.__saveY, ctrl, shift, key, 0, keySym)
    self._Iren.KeyPressEvent()
    self._Iren.CharEvent()

def keyReleaseEvent(self, ev):
    key, keySym = self._GetKeyCharAndKeySym(ev)
    ctrl, shift = self._GetCtrlShift(ev)
    self._setEventInformation(self.__saveX, self.__saveY, ctrl, shift, key, 0, keySym)
    self._Iren.KeyReleaseEvent()

def wheelEvent(self, ev):
    if hasattr(ev, 'delta'):
        self.__wheelDelta += ev.delta()
    else:
        self.__wheelDelta += ev.angleDelta().y()

    if self.__wheelDelta >= 120:
        self._Iren.MouseWheelForwardEvent()
        self.__wheelDelta = 0
    elif self.__wheelDelta <= -120:
        self._Iren.MouseWheelBackwardEvent()
        self.__wheelDelta = 0

def GetRenderWindow(self):
    return self._RenderWindow

def Render(self):
    self.update()

def QVTKRenderWidgetConeExample(block=False): """A simple example that uses the QVTKRenderWindowInteractor class."""

import vtkmodules.vtkInteractionStyle

# load implementations for rendering and interaction factory classes
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkFiltersSources import vtkConeSource
from vtkmodules.vtkRenderingCore import vtkActor, vtkPolyDataMapper, vtkRenderer

# every QT app needs an app
app = QApplication.instance()
if not app:  # pragma: no cover
    app = QApplication(["PyVista"])

window = QMainWindow()

# create the widget
widget = QVTKRenderWindowInteractor(window)
window.setCentralWidget(widget)
# if you don't want the 'q' key to exit comment this.
widget.AddObserver("ExitEvent", lambda o, e, a=app: a.quit())

ren = vtkRenderer()
widget.GetRenderWindow().AddRenderer(ren)

cone = vtkConeSource()
cone.SetResolution(8)

coneMapper = vtkPolyDataMapper()
coneMapper.SetInputConnection(cone.GetOutputPort())

coneActor = vtkActor()
coneActor.SetMapper(coneMapper)

ren.AddActor(coneActor)

# show the widget
window.show()

widget.Initialize()
widget.Start()

# start event processing
# Source: https://doc.qt.io/qtforpython/porting_from2.html
# 'exec_' is deprecated and will be removed in the future.
# Use 'exec' instead.
if block:
    try:
        app.exec()
    except AttributeError:
        app.exec_()

_keysyms_for_ascii = ( None, None, None, None, None, None, None, None, None, "Tab", None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, "space", "exclam", "quotedbl", "numbersign", "dollar", "percent", "ampersand", "quoteright", "parenleft", "parenright", "asterisk", "plus", "comma", "minus", "period", "slash", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "colon", "semicolon", "less", "equal", "greater", "question", "at", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "bracketleft", "backslash", "bracketright", "asciicircum", "underscore", "quoteleft", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "braceleft", "bar", "braceright", "asciitilde", "Delete", )

_keysyms = { Key.Key_Backspace: 'BackSpace', Key.Key_Tab: 'Tab', Key.Key_Backtab: 'Tab', # Key.Key_Clear : 'Clear', Key.Key_Return: 'Return', Key.Key_Enter: 'Return', Key.Key_Shift: 'Shift_L', Key.Key_Control: 'Control_L', Key.Key_Alt: 'Alt_L', Key.Key_Pause: 'Pause', Key.Key_CapsLock: 'Caps_Lock', Key.Key_Escape: 'Escape', Key.Key_Space: 'space', # Key.Key_Prior : 'Prior', # Key.Key_Next : 'Next', Key.Key_End: 'End', Key.Key_Home: 'Home', Key.Key_Left: 'Left', Key.Key_Up: 'Up', Key.Key_Right: 'Right', Key.Key_Down: 'Down', Key.Key_SysReq: 'Snapshot', Key.Key_Insert: 'Insert', Key.Key_Delete: 'Delete', Key.Key_Help: 'Help', Key.Key_0: '0', Key.Key_1: '1', Key.Key_2: '2', Key.Key_3: '3', Key.Key_4: '4', Key.Key_5: '5', Key.Key_6: '6', Key.Key_7: '7', Key.Key_8: '8', Key.Key_9: '9', Key.Key_A: 'a', Key.Key_B: 'b', Key.Key_C: 'c', Key.Key_D: 'd', Key.Key_E: 'e', Key.Key_F: 'f', Key.Key_G: 'g', Key.Key_H: 'h', Key.Key_I: 'i', Key.Key_J: 'j', Key.Key_K: 'k', Key.Key_L: 'l', Key.Key_M: 'm', Key.Key_N: 'n', Key.Key_O: 'o', Key.Key_P: 'p', Key.Key_Q: 'q', Key.Key_R: 'r', Key.Key_S: 's', Key.Key_T: 't', Key.Key_U: 'u', Key.Key_V: 'v', Key.Key_W: 'w', Key.Key_X: 'x', Key.Key_Y: 'y', Key.Key_Z: 'z', Key.Key_Asterisk: 'asterisk', Key.Key_Plus: 'plus', Key.Key_Minus: 'minus', Key.Key_Period: 'period', Key.Key_Slash: 'slash', Key.Key_F1: 'F1', Key.Key_F2: 'F2', Key.Key_F3: 'F3', Key.Key_F4: 'F4', Key.Key_F5: 'F5', Key.Key_F6: 'F6', Key.Key_F7: 'F7', Key.Key_F8: 'F8', Key.Key_F9: 'F9', Key.Key_F10: 'F10', Key.Key_F11: 'F11', Key.Key_F12: 'F12', Key.Key_F13: 'F13', Key.Key_F14: 'F14', Key.Key_F15: 'F15', Key.Key_F16: 'F16', Key.Key_F17: 'F17', Key.Key_F18: 'F18', Key.Key_F19: 'F19', Key.Key_F20: 'F20', Key.Key_F21: 'F21', Key.Key_F22: 'F22', Key.Key_F23: 'F23', Key.Key_F24: 'F24', Key.Key_NumLock: 'Num_Lock', Key.Key_ScrollLock: 'Scroll_Lock', }

if name == "main": print(PyQtImpl) QVTKRenderWidgetConeExample()

I get the following printout:

Qt 6.3.1 (x86_64-little_endian-llp64 shared (dynamic) release build; by MSVC 2019) [limited API]

Python 3.8.10 (tags/v3.8.10:3d8993a, May  3 2021, 11:48:03) [MSC v.1928 64 bit (AMD64)]
Vendor: NVIDIA Corporation
Renderer: Quadro RTX 8000/PCIe/SSE2
Version: 4.6.0 NVIDIA 516.59
Shading language: 4.60 NVIDIA
Context Format: compatibility version 4.6

Surface Format: compatibility version 4.6
Qt 6.3.1 (x86_64-little_endian-llp64 shared (dynamic) release build; by MSVC 2019) [limited API]

Python 3.8.10 (tags/v3.8.10:3d8993a, May  3 2021, 11:48:03) [MSC v.1928 64 bit (AMD64)]
Vendor: NVIDIA Corporation
Renderer: Quadro RTX 8000/PCIe/SSE2
Version: 4.5.0 NVIDIA 516.59
Shading language: 4.50 NVIDIA
Context Format: compatibility version 4.6

Surface Format: compatibility version 4.6
QWindowsGLContext::makeCurrent: SetPixelFormat() failed (The pixel format is invalid.)
qt.qpa.backingstore: composeAndFlush: makeCurrent() failed

[adam-grant-hendry]

Adding also the following examples:

• OpenGL Window Example
• Threaded QOpenGLWidget Example

[adam-grant-hendry]

I believe with respect to the SetPixelFormat() error above, the pixel format will have to be properly set per platform. On Windows:

• SetPixelFormat function (wingdi.h)

Correspondingly in vtkWin32OpenGLRenderWindow:

virtual void SetupPixelFormatPaletteAndContext (HDC hDC, DWORD dwFlags, int debug, int bpp=16, int zbpp=16)

[adam-grant-hendry]

The pixel format error comes from here:

qtbase/qwindowsglcontext.cpp, Line 1287

[adam-grant-hendry]

An important note on differences between QGLWidget and QOpenGLWidget:

• Relation to QGLWidget

The key takeaway is this:

While the API is very similar, there is an important difference between the two: QOpenGLWidget always renders offscreen, using framebuffer objects. QGLWidget on the other hand uses a native window and surface. The latter causes issues when using it in complex user interfaces since, depending on the platform, such native child widgets may have various limitations, regarding stacking orders for example. QOpenGLWidget avoids this by not creating a separate native window.

@wmvanvliet I suspect this is why switching back to QGLWidget worked for you. The QVTKRenderWindowInteractor appears designed around this old architecture.

@prabhuramachandran @larsoner After investigating, it looks like QVTKRenderWindowInteractor will require a rewrite to support the newer QOpenGLWidget. pyvistaqt has already pulled in the vtk upstream changes, and these do not solve the problem (at least on my Windows 10 machine with an NVIDIA gpu).

Since the QGL classes are obsolete or near deprecation and the vtk folks have previously explained they don't have time to maintain this, I think it will become more important for mayavi, pyvista, and other packages using Qt to work together towards a solution.

[adam-grant-hendry]

@prabhuramachandran @wmvanvliet @larsoner Digging deeper, I found this interesting article, which may prove valuable when supporting both vtk <= 8 and vkt 9+:

Widget	Use Case
QVTKWidget	Used to display vtkRenderWindow in Qt's QWidget
QVTKWidget2	Used to display vtkRenderWindow in Qt's QGLWidget
QVTKOpenGLWidget	Used to display vtkRenderWindow in Qt's QWidget
QVTKOpenGLNativeWidget	Used to display vtkGenericOpenGLRenderWindow in Qt's QOpenGLWidget

• For Qt <5.4, use QVTKWidget2
• For Qt 5.4+, VTK <=8.1, use QVTKOpenGLWidget for versions
• For Qt 5.4+, VTK 8.2+, use QVTKOpenGLNativeWidget

However, in truth, I don't think any of these widgets are available from the vtk 9.1.0 PyPI package.

@prabhuramachandran I'm seeing your name here as a maintainer (you're quite the popular developer!). We may need to have these extras built and added to the vtk PyPI repo so they can be used in upgrading the QVTKRenderWindowInteractor.

[prabhuramachandran]

Thanks @adam-grant-hendry for all the additional information!

We could try a zoom meeting during the sprints but I am not sure how effective it will be. Are you around tomorrow evening? We could at least discuss this then.

I think building the extras is not a scalable option as a PyPI wheel would then be built against a very specific Qt version and that would be a nightmare to maintain or even install given the different kinds of environments users have. One option is to decide to not support VTK <= 8.

[adam-grant-hendry]

@prabhuramachandran You're a stud! Can't believe you're still up!

Yes, agreed...I think Zoom won't be very effective. I am around tomorrow evening (only online though).

I think supporting VTK >=9 makes sense. The only reason is the majority of open source package maintainers are worried by the licensing terms of the PyQt libraries, which is why they want to move to PySide. However, additionally there is the issue that the QGL classes are now (or soon becoming) obsolete, which goes beyond PyQt vs PySide.

I haven't heard back from anyone on the pyvista side, but you could certainly do it for mayavi if you get consensus. I guess/believe pyvista might be of the same opinion, but I'm of the opinion that rising tides raise all boats. If you come up with a working solution for mayavi, pyvista and others are soon to follow.

What are your opinions? And what time would you like to meet tomorrow? I'm in California, so our time zones (relative to Texas) won't be too far off.

[adam-grant-hendry]

@prabhuramachandran Actually, instead, I recommend we should look at the source code for

• QVTKOpenGLNativeWidget

in

GUISupport/Qt

and leverage what source code we can there for QVTKRenderWindowInteractor.py to make it work.

ASIDE: It also looks like pieces of these classes are deprecated in vtk 9.2, but replaced with different functions.

[adam-grant-hendry]

@prabhuramachandran Another alternative would be to create another PyPI repo for additional dependencies, including these QVTK classes.

e.g. If you use pylint and put your configuration settings in a pyproject.toml, you need the toml library and the additional way of specifying that as an extra dependency is to add the name of the library in square brackets.

On Windows in PowerShell, this is:

PS> py -m pip install pylint[toml]

Hence we could add/remove pieces as needed. This is similar to how vtkmodules separated pieces of vtk into separate modules.

[adam-grant-hendry]

@prabhuramachandran @wmvanvliet @larsoner If I try to switch

if rw:  # user-supplied render window
    self._RenderWindow = rw
else:
    self._RenderWindow = vtkGenericOpenGLRenderWindow()

I get the error:

2022-07-12 11:35:49.389 (   1.031s) [                ]vtkOpenGLRenderWindow.c:493    ERR| vtkGenericOpenGLRenderWindow (00000233F9899E90): GLEW could not be initialized: Missing GL version
ERROR:root:GLEW could not be initialized: Missing GL version

Even though vtkmodules ships with vtkglew-9.1dll . If I run

PS> glewinfo

I get the following glewinfo.txt, which seems to indicate everything is in order:

glewinfo.txt

I've also run vtkProbeOpenGLVersion-9.1.exe

Do you have any idea what's going wrong here?

[adam-grant-hendry]

@prabhuramachandran @wmvanvliet @larsoner I stumbled upon a bit of blind luck today. When I change rwi.py to do this:

if rw:  # user-supplied render window
    self._RenderWindow = rw
else:
    self._RenderWindow = vtkRenderWindow()

WId = self.winId()

...

# self._RenderWindow.SetWindowInfo(str(int(WId)))  # Comment this out

Here's the full file:

pyvistaqt/rwi.py

# modified from: https://gitlab.kitware.com/vtk/vtk
# under the OSI-approved BSD 3-clause License
# TODO: Mayavi has a potentially different version that might be better or worse
# coding=utf-8
"""
A simple VTK widget for PyQt or PySide.
See http://www.trolltech.com for Qt documentation,
http://www.riverbankcomputing.co.uk for PyQt, and
http://pyside.github.io for PySide.

This class is based on the vtkGenericRenderWindowInteractor and is
therefore fairly powerful.  It should also play nicely with the
vtk3DWidget code.

Created by Prabhu Ramachandran, May 2002
Based on David Gobbi's QVTKRenderWidget.py

Changes by Gerard Vermeulen Feb. 2003
 Win32 support.

Changes by Gerard Vermeulen, May 2003
 Bug fixes and better integration with the Qt framework.

Changes by Phil Thompson, Nov. 2006
 Ported to PyQt v4.
 Added support for wheel events.

Changes by Phil Thompson, Oct. 2007
 Bug fixes.

Changes by Phil Thompson, Mar. 2008
 Added cursor support.

Changes by Rodrigo Mologni, Sep. 2013 (Credit to Daniele Esposti)
 Bug fix to PySide: Converts PyCObject to void pointer.

Changes by Greg Schussman, Aug. 2014
 The keyPressEvent function now passes keysym instead of None.

Changes by Alex Tsui, Apr. 2015
 Port from PyQt4 to PyQt5.

Changes by Fabian Wenzel, Jan. 2016
 Support for Python3

Changes by Tobias Hänel, Sep. 2018
 Support for PySide2

Changes by Ruben de Bruin, Aug. 2019
 Fixes to the keyPressEvent function

Changes by Chen Jintao, Aug. 2021
 Support for PySide6

Changes by Eric Larson and Guillaume Favelier, Apr. 2022
 Support for PyQt6
"""
import os

# Check whether a specific PyQt implementation was chosen
try:
    import vtkmodules.qt

    PyQtImpl = vtkmodules.qt.PyQtImpl
except ImportError:
    pass

# Check whether a specific QVTKRenderWindowInteractor base
# class was chosen, can be set to "QGLWidget" in
# PyQt implementation version lower than Pyside6,
# or "QOpenGLWidget" in Pyside6
QVTKRWIBase = "QWidget"
try:
    import vtkmodules.qt

    QVTKRWIBase = vtkmodules.qt.QVTKRWIBase
except ImportError:
    pass

from vtkmodules.vtkRenderingCore import vtkRenderWindow
from vtkmodules.vtkRenderingUI import vtkGenericRenderWindowInteractor

if PyQtImpl is None:
    # Autodetect the PyQt implementation to use
    try:
        import PyQt6

        PyQtImpl = "PyQt6"
    except ImportError:
        try:
            import PySide6

            PyQtImpl = "PySide6"
        except ImportError:
            try:
                import PyQt5

                PyQtImpl = "PyQt5"
            except ImportError:
                try:
                    import PySide2

                    PyQtImpl = "PySide2"
                except ImportError:
                    try:
                        import PyQt4

                        PyQtImpl = "PyQt4"
                    except ImportError:
                        try:
                            import PySide

                            PyQtImpl = "PySide"
                        except ImportError:
                            raise ImportError("Cannot load either PyQt or PySide")

# Check the compatibility of PyQtImpl and QVTKRWIBase
if QVTKRWIBase != "QWidget":
    if PyQtImpl in ["PyQt6", "PySide6"] and QVTKRWIBase == "QOpenGLWidget":
        pass  # compatible
    elif (
        PyQtImpl in ["PyQt5", "PySide2", "PyQt4", "PySide"] and QVTKRWIBase == "QGLWidget"
    ):
        pass  # compatible
    else:
        raise ImportError("Cannot load " + QVTKRWIBase + " from " + PyQtImpl)

if PyQtImpl == "PyQt6":
    if QVTKRWIBase == "QOpenGLWidget":
        from PyQt6.QtOpenGLWidgets import QOpenGLWidget
    from PyQt6.QtCore import QEvent, QObject, QSize, Qt, QTimer
    from PyQt6.QtGui import QCursor
    from PyQt6.QtWidgets import QApplication, QMainWindow, QSizePolicy, QWidget
elif PyQtImpl == "PySide6":
    if QVTKRWIBase == "QOpenGLWidget":
        from PySide6.QtOpenGLWidgets import QOpenGLWidget
    from PySide6.QtCore import QEvent, QObject, QSize, Qt, QTimer
    from PySide6.QtGui import QCursor
    from PySide6.QtWidgets import QApplication, QMainWindow, QSizePolicy, QWidget
elif PyQtImpl == "PyQt5":
    if QVTKRWIBase == "QGLWidget":
        from PyQt5.QtOpenGL import QGLWidget
    from PyQt5.QtCore import QEvent, QObject, QSize, Qt, QTimer
    from PyQt5.QtGui import QCursor
    from PyQt5.QtWidgets import QApplication, QMainWindow, QSizePolicy, QWidget
elif PyQtImpl == "PySide2":
    if QVTKRWIBase == "QGLWidget":
        from PySide2.QtOpenGL import QGLWidget
    from PySide2.QtCore import QEvent, QObject, QSize, Qt, QTimer
    from PySide2.QtGui import QCursor
    from PySide2.QtWidgets import QApplication, QMainWindow, QSizePolicy, QWidget
elif PyQtImpl == "PyQt4":
    if QVTKRWIBase == "QGLWidget":
        from PyQt4.QtOpenGL import QGLWidget
    from PyQt4.QtCore import QEvent, QObject, QSize, Qt, QTimer
    from PyQt4.QtGui import QApplication, QMainWindow, QSizePolicy, QWidget
elif PyQtImpl == "PySide":
    if QVTKRWIBase == "QGLWidget":
        from PySide.QtOpenGL import QGLWidget
    from PySide.QtCore import QEvent, QObject, QSize, Qt, QTimer
    from PySide.QtGui import QApplication, QMainWindow, QSizePolicy, QWidget
else:
    raise ImportError("Unknown PyQt implementation " + repr(PyQtImpl))

# Define types for base class, based on string
if QVTKRWIBase == "QWidget":
    QVTKRWIBaseClass = QWidget
elif QVTKRWIBase == "QGLWidget":
    QVTKRWIBaseClass = QGLWidget
elif QVTKRWIBase == "QOpenGLWidget":
    QVTKRWIBaseClass = QOpenGLWidget
else:
    raise ImportError("Unknown base class for QVTKRenderWindowInteractor " + QVTKRWIBase)

if PyQtImpl == 'PyQt6':
    CursorShape = Qt.CursorShape
    MouseButton = Qt.MouseButton
    WindowType = Qt.WindowType
    WidgetAttribute = Qt.WidgetAttribute
    KeyboardModifier = Qt.KeyboardModifier
    FocusPolicy = Qt.FocusPolicy
    ConnectionType = Qt.ConnectionType
    Key = Qt.Key
    SizePolicy = QSizePolicy.Policy
    EventType = QEvent.Type
else:
    CursorShape = (
        MouseButton
    ) = (
        WindowType
    ) = WidgetAttribute = KeyboardModifier = FocusPolicy = ConnectionType = Key = Qt
    SizePolicy = QSizePolicy
    EventType = QEvent

if PyQtImpl in ('PyQt4', 'PySide'):
    MiddleButton = MouseButton.MidButton
else:
    MiddleButton = MouseButton.MiddleButton


def _get_event_pos(ev):
    try:  # Qt6+
        return ev.position().x(), ev.position().y()
    except AttributeError:  # Qt5
        return ev.x(), ev.y()


class QVTKRenderWindowInteractor(QVTKRWIBaseClass):

    """A QVTKRenderWindowInteractor for Python and Qt.  Uses a
    vtkGenericRenderWindowInteractor to handle the interactions.  Use
    GetRenderWindow() to get the vtkRenderWindow.  Create with the
    keyword stereo=1 in order to generate a stereo-capable window.

    The user interface is summarized in vtkInteractorStyle.h:

    - Keypress j / Keypress t: toggle between joystick (position
    sensitive) and trackball (motion sensitive) styles. In joystick
    style, motion occurs continuously as long as a mouse button is
    pressed. In trackball style, motion occurs when the mouse button
    is pressed and the mouse pointer moves.

    - Keypress c / Keypress o: toggle between camera and object
    (actor) modes. In camera mode, mouse events affect the camera
    position and focal point. In object mode, mouse events affect
    the actor that is under the mouse pointer.

    - Button 1: rotate the camera around its focal point (if camera
    mode) or rotate the actor around its origin (if actor mode). The
    rotation is in the direction defined from the center of the
    renderer's viewport towards the mouse position. In joystick mode,
    the magnitude of the rotation is determined by the distance the
    mouse is from the center of the render window.

    - Button 2: pan the camera (if camera mode) or translate the actor
    (if object mode). In joystick mode, the direction of pan or
    translation is from the center of the viewport towards the mouse
    position. In trackball mode, the direction of motion is the
    direction the mouse moves. (Note: with 2-button mice, pan is
    defined as <Shift>-Button 1.)

    - Button 3: zoom the camera (if camera mode) or scale the actor
    (if object mode). Zoom in/increase scale if the mouse position is
    in the top half of the viewport; zoom out/decrease scale if the
    mouse position is in the bottom half. In joystick mode, the amount
    of zoom is controlled by the distance of the mouse pointer from
    the horizontal centerline of the window.

    - Keypress 3: toggle the render window into and out of stereo
    mode.  By default, red-blue stereo pairs are created. Some systems
    support Crystal Eyes LCD stereo glasses; you have to invoke
    SetStereoTypeToCrystalEyes() on the rendering window.  Note: to
    use stereo you also need to pass a stereo=1 keyword argument to
    the constructor.

    - Keypress e: exit the application.

    - Keypress f: fly to the picked point

    - Keypress p: perform a pick operation. The render window interactor
    has an internal instance of vtkCellPicker that it uses to pick.

    - Keypress r: reset the camera view along the current view
    direction. Centers the actors and moves the camera so that all actors
    are visible.

    - Keypress s: modify the representation of all actors so that they
    are surfaces.

    - Keypress u: invoke the user-defined function. Typically, this
    keypress will bring up an interactor that you can type commands in.

    - Keypress w: modify the representation of all actors so that they
    are wireframe.
    """

    # Map between VTK and Qt cursors.
    _CURSOR_MAP = {
        0: CursorShape.ArrowCursor,  # VTK_CURSOR_DEFAULT
        1: CursorShape.ArrowCursor,  # VTK_CURSOR_ARROW
        2: CursorShape.SizeBDiagCursor,  # VTK_CURSOR_SIZENE
        3: CursorShape.SizeFDiagCursor,  # VTK_CURSOR_SIZENWSE
        4: CursorShape.SizeBDiagCursor,  # VTK_CURSOR_SIZESW
        5: CursorShape.SizeFDiagCursor,  # VTK_CURSOR_SIZESE
        6: CursorShape.SizeVerCursor,  # VTK_CURSOR_SIZENS
        7: CursorShape.SizeHorCursor,  # VTK_CURSOR_SIZEWE
        8: CursorShape.SizeAllCursor,  # VTK_CURSOR_SIZEALL
        9: CursorShape.PointingHandCursor,  # VTK_CURSOR_HAND
        10: CursorShape.CrossCursor,  # VTK_CURSOR_CROSSHAIR
    }

    def __init__(self, parent=None, **kw):
        # the current button
        self._ActiveButton = MouseButton.NoButton

        # private attributes
        self.__saveX = 0
        self.__saveY = 0
        self.__saveModifiers = KeyboardModifier.NoModifier
        self.__saveButtons = MouseButton.NoButton
        self.__wheelDelta = 0

        # do special handling of some keywords:
        # stereo, rw

        try:
            stereo = bool(kw['stereo'])
        except KeyError:
            stereo = False

        try:
            rw = kw['rw']
        except KeyError:
            rw = None

        # create base qt-level widget
        if QVTKRWIBase == "QWidget":
            if "wflags" in kw:
                wflags = kw['wflags']
            else:
                wflags = Qt.WindowType.Widget
            QWidget.__init__(self, parent, wflags | WindowType.MSWindowsOwnDC)
        elif QVTKRWIBase == "QGLWidget":
            QGLWidget.__init__(self, parent)
        elif QVTKRWIBase == "QOpenGLWidget":
            QOpenGLWidget.__init__(self, parent)

        if rw:  # user-supplied render window
            self._RenderWindow = rw
        else:
            self._RenderWindow = vtkRenderWindow()

        WId = self.winId()

        # Python2
        if type(WId).__name__ == 'PyCObject':
            from ctypes import c_void_p, py_object, pythonapi

            pythonapi.PyCObject_AsVoidPtr.restype = c_void_p
            pythonapi.PyCObject_AsVoidPtr.argtypes = [py_object]

            WId = pythonapi.PyCObject_AsVoidPtr(WId)

        # Python3
        elif type(WId).__name__ == 'PyCapsule':
            from ctypes import c_char_p, c_void_p, py_object, pythonapi

            pythonapi.PyCapsule_GetName.restype = c_char_p
            pythonapi.PyCapsule_GetName.argtypes = [py_object]

            name = pythonapi.PyCapsule_GetName(WId)

            pythonapi.PyCapsule_GetPointer.restype = c_void_p
            pythonapi.PyCapsule_GetPointer.argtypes = [py_object, c_char_p]

            WId = pythonapi.PyCapsule_GetPointer(WId, name)

        # self._RenderWindow.SetWindowInfo(str(int(WId)))

        if stereo:  # stereo mode
            self._RenderWindow.StereoCapableWindowOn()
            self._RenderWindow.SetStereoTypeToCrystalEyes()

        try:
            self._Iren = kw['iren']
        except KeyError:
            self._Iren = vtkGenericRenderWindowInteractor()
            self._Iren.SetRenderWindow(self._RenderWindow)

        # do all the necessary qt setup
        self.setAttribute(WidgetAttribute.WA_OpaquePaintEvent)
        if os.name == 'posix':
            self.setAttribute(WidgetAttribute.WA_PaintOnScreen)
        self.setMouseTracking(True)  # get all mouse events
        self.setFocusPolicy(FocusPolicy.WheelFocus)
        self.setSizePolicy(QSizePolicy(SizePolicy.Expanding, SizePolicy.Expanding))

        self._Timer = QTimer(self)
        self._Timer.timeout.connect(self.TimerEvent)

        self._Iren.AddObserver('CreateTimerEvent', self.CreateTimer)
        self._Iren.AddObserver('DestroyTimerEvent', self.DestroyTimer)
        self._Iren.GetRenderWindow().AddObserver(
            'CursorChangedEvent', self.CursorChangedEvent
        )

        # If we've a parent, it does not close the child when closed.
        # Connect the parent's destroyed signal to this widget's close
        # slot for proper cleanup of VTK objects.
        if self.parent():
            self.parent().destroyed.connect(self.close, ConnectionType.DirectConnection)

    def __getattr__(self, attr):
        """Makes the object behave like a vtkGenericRenderWindowInteractor"""
        if attr == '__vtk__':
            return lambda t=self._Iren: t
        elif hasattr(self._Iren, attr):
            return getattr(self._Iren, attr)
        else:
            raise AttributeError(
                self.__class__.__name__ + " has no attribute named " + attr
            )

    def Finalize(self):
        '''
        Call internal cleanup method on VTK objects
        '''
        self._RenderWindow.Finalize()

    def CreateTimer(self, obj, evt):
        self._Timer.start(10)

    def DestroyTimer(self, obj, evt):
        self._Timer.stop()
        return 1

    def TimerEvent(self):
        self._Iren.TimerEvent()

    def CursorChangedEvent(self, obj, evt):
        """Called when the CursorChangedEvent fires on the render window."""
        # This indirection is needed since when the event fires, the current
        # cursor is not yet set so we defer this by which time the current
        # cursor should have been set.
        QTimer.singleShot(0, self.ShowCursor)

    def HideCursor(self):
        """Hides the cursor."""
        self.setCursor(Qt.BlankCursor)

    def ShowCursor(self):
        """Shows the cursor."""
        vtk_cursor = self._Iren.GetRenderWindow().GetCurrentCursor()
        qt_cursor = self._CURSOR_MAP.get(vtk_cursor, Qt.ArrowCursor)
        self.setCursor(qt_cursor)

    def closeEvent(self, evt):
        self.Finalize()

    def sizeHint(self):
        return QSize(400, 400)

    def paintEngine(self):
        return None

    def paintEvent(self, ev):
        self._Iren.Render()

    def resizeEvent(self, ev):
        scale = self._getPixelRatio()
        w = int(round(scale * self.width()))
        h = int(round(scale * self.height()))
        self._RenderWindow.SetDPI(int(round(72 * scale)))
        vtkRenderWindow.SetSize(self._RenderWindow, w, h)
        self._Iren.SetSize(w, h)
        self._Iren.ConfigureEvent()
        self.update()

    def _GetKeyCharAndKeySym(self, ev):
        """Convert a Qt key into a char and a vtk keysym.

        This is essentially copied from the c++ implementation in
        GUISupport/Qt/QVTKInteractorAdapter.cxx.
        """
        # if there is a char, convert its ASCII code to a VTK keysym
        try:
            keyChar = ev.text()[0]
            keySym = _keysyms_for_ascii[ord(keyChar)]
        except IndexError:
            keyChar = '\0'
            keySym = None

        # next, try converting Qt key code to a VTK keysym
        if keySym is None:
            try:
                keySym = _keysyms[ev.key()]
            except KeyError:
                keySym = None

        # use "None" as a fallback
        if keySym is None:
            keySym = "None"

        return keyChar, keySym

    def _GetCtrlShift(self, ev):
        ctrl = shift = False

        if hasattr(ev, 'modifiers'):
            if ev.modifiers() & KeyboardModifier.ShiftModifier:
                shift = True
            if ev.modifiers() & KeyboardModifier.ControlModifier:
                ctrl = True
        else:
            if self.__saveModifiers & KeyboardModifier.ShiftModifier:
                shift = True
            if self.__saveModifiers & KeyboardModifier.ControlModifier:
                ctrl = True

        return ctrl, shift

    @staticmethod
    def _getPixelRatio():
        if PyQtImpl in ["PyQt5", "PySide2", "PySide6"]:
            # Source: https://stackoverflow.com/a/40053864/3388962
            pos = QCursor.pos()
            for screen in QApplication.screens():
                rect = screen.geometry()
                if rect.contains(pos):
                    return screen.devicePixelRatio()
            # Should never happen, but try to find a good fallback.
            return QApplication.instance().devicePixelRatio()
        else:
            # Qt4 seems not to provide any cross-platform means to get the
            # pixel ratio.
            return 1.0

    def _setEventInformation(self, x, y, ctrl, shift, key, repeat=0, keysum=None):
        scale = self._getPixelRatio()
        self._Iren.SetEventInformation(
            int(round(x * scale)),
            int(round((self.height() - y - 1) * scale)),
            ctrl,
            shift,
            key,
            repeat,
            keysum,
        )

    def enterEvent(self, ev):
        ctrl, shift = self._GetCtrlShift(ev)
        self._setEventInformation(
            self.__saveX, self.__saveY, ctrl, shift, chr(0), 0, None
        )
        self._Iren.EnterEvent()

    def leaveEvent(self, ev):
        ctrl, shift = self._GetCtrlShift(ev)
        self._setEventInformation(
            self.__saveX, self.__saveY, ctrl, shift, chr(0), 0, None
        )
        self._Iren.LeaveEvent()

    def mousePressEvent(self, ev):
        pos_x, pos_y = _get_event_pos(ev)
        ctrl, shift = self._GetCtrlShift(ev)
        repeat = 0
        if ev.type() == EventType.MouseButtonDblClick:
            repeat = 1
        self._setEventInformation(pos_x, pos_y, ctrl, shift, chr(0), repeat, None)

        self._ActiveButton = ev.button()

        if self._ActiveButton == MouseButton.LeftButton:
            self._Iren.LeftButtonPressEvent()
        elif self._ActiveButton == MouseButton.RightButton:
            self._Iren.RightButtonPressEvent()
        elif self._ActiveButton == MiddleButton:
            self._Iren.MiddleButtonPressEvent()

    def mouseReleaseEvent(self, ev):
        pos_x, pos_y = _get_event_pos(ev)
        ctrl, shift = self._GetCtrlShift(ev)
        self._setEventInformation(pos_x, pos_y, ctrl, shift, chr(0), 0, None)

        if self._ActiveButton == MouseButton.LeftButton:
            self._Iren.LeftButtonReleaseEvent()
        elif self._ActiveButton == MouseButton.RightButton:
            self._Iren.RightButtonReleaseEvent()
        elif self._ActiveButton == MiddleButton:
            self._Iren.MiddleButtonReleaseEvent()

    def mouseMoveEvent(self, ev):
        pos_x, pos_y = _get_event_pos(ev)
        self.__saveModifiers = ev.modifiers()
        self.__saveButtons = ev.buttons()
        self.__saveX = pos_x
        self.__saveY = pos_y

        ctrl, shift = self._GetCtrlShift(ev)
        self._setEventInformation(pos_x, pos_y, ctrl, shift, chr(0), 0, None)
        self._Iren.MouseMoveEvent()

    def keyPressEvent(self, ev):
        key, keySym = self._GetKeyCharAndKeySym(ev)
        ctrl, shift = self._GetCtrlShift(ev)
        self._setEventInformation(self.__saveX, self.__saveY, ctrl, shift, key, 0, keySym)
        self._Iren.KeyPressEvent()
        self._Iren.CharEvent()

    def keyReleaseEvent(self, ev):
        key, keySym = self._GetKeyCharAndKeySym(ev)
        ctrl, shift = self._GetCtrlShift(ev)
        self._setEventInformation(self.__saveX, self.__saveY, ctrl, shift, key, 0, keySym)
        self._Iren.KeyReleaseEvent()

    def wheelEvent(self, ev):
        if hasattr(ev, 'delta'):
            self.__wheelDelta += ev.delta()
        else:
            self.__wheelDelta += ev.angleDelta().y()

        if self.__wheelDelta >= 120:
            self._Iren.MouseWheelForwardEvent()
            self.__wheelDelta = 0
        elif self.__wheelDelta <= -120:
            self._Iren.MouseWheelBackwardEvent()
            self.__wheelDelta = 0

    def GetRenderWindow(self):
        return self._RenderWindow

    def Render(self):
        self.update()


def QVTKRenderWidgetConeExample(block=False):
    """A simple example that uses the QVTKRenderWindowInteractor class."""

    import vtkmodules.vtkInteractionStyle

    # load implementations for rendering and interaction factory classes
    import vtkmodules.vtkRenderingOpenGL2
    from vtkmodules.vtkFiltersSources import vtkConeSource
    from vtkmodules.vtkRenderingCore import vtkActor, vtkPolyDataMapper, vtkRenderer

    # every QT app needs an app
    app = QApplication.instance()
    if not app:  # pragma: no cover
        app = QApplication(["PyVista"])

    window = QMainWindow()

    # create the widget
    widget = QVTKRenderWindowInteractor(window)
    window.setCentralWidget(widget)
    # if you don't want the 'q' key to exit comment this.
    widget.AddObserver("ExitEvent", lambda o, e, a=app: a.quit())

    ren = vtkRenderer()
    widget.GetRenderWindow().AddRenderer(ren)

    cone = vtkConeSource()
    cone.SetResolution(8)

    coneMapper = vtkPolyDataMapper()
    coneMapper.SetInputConnection(cone.GetOutputPort())

    coneActor = vtkActor()
    coneActor.SetMapper(coneMapper)

    ren.AddActor(coneActor)

    # show the widget
    window.show()

    widget.Initialize()
    widget.Start()

    # start event processing
    # Source: https://doc.qt.io/qtforpython/porting_from2.html
    # 'exec_' is deprecated and will be removed in the future.
    # Use 'exec' instead.
    if block:
        try:
            app.exec()
        except AttributeError:
            app.exec_()


_keysyms_for_ascii = (
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    "Tab",
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    None,
    "space",
    "exclam",
    "quotedbl",
    "numbersign",
    "dollar",
    "percent",
    "ampersand",
    "quoteright",
    "parenleft",
    "parenright",
    "asterisk",
    "plus",
    "comma",
    "minus",
    "period",
    "slash",
    "0",
    "1",
    "2",
    "3",
    "4",
    "5",
    "6",
    "7",
    "8",
    "9",
    "colon",
    "semicolon",
    "less",
    "equal",
    "greater",
    "question",
    "at",
    "A",
    "B",
    "C",
    "D",
    "E",
    "F",
    "G",
    "H",
    "I",
    "J",
    "K",
    "L",
    "M",
    "N",
    "O",
    "P",
    "Q",
    "R",
    "S",
    "T",
    "U",
    "V",
    "W",
    "X",
    "Y",
    "Z",
    "bracketleft",
    "backslash",
    "bracketright",
    "asciicircum",
    "underscore",
    "quoteleft",
    "a",
    "b",
    "c",
    "d",
    "e",
    "f",
    "g",
    "h",
    "i",
    "j",
    "k",
    "l",
    "m",
    "n",
    "o",
    "p",
    "q",
    "r",
    "s",
    "t",
    "u",
    "v",
    "w",
    "x",
    "y",
    "z",
    "braceleft",
    "bar",
    "braceright",
    "asciitilde",
    "Delete",
)

_keysyms = {
    Key.Key_Backspace: 'BackSpace',
    Key.Key_Tab: 'Tab',
    Key.Key_Backtab: 'Tab',
    # Key.Key_Clear : 'Clear',
    Key.Key_Return: 'Return',
    Key.Key_Enter: 'Return',
    Key.Key_Shift: 'Shift_L',
    Key.Key_Control: 'Control_L',
    Key.Key_Alt: 'Alt_L',
    Key.Key_Pause: 'Pause',
    Key.Key_CapsLock: 'Caps_Lock',
    Key.Key_Escape: 'Escape',
    Key.Key_Space: 'space',
    # Key.Key_Prior : 'Prior',
    # Key.Key_Next : 'Next',
    Key.Key_End: 'End',
    Key.Key_Home: 'Home',
    Key.Key_Left: 'Left',
    Key.Key_Up: 'Up',
    Key.Key_Right: 'Right',
    Key.Key_Down: 'Down',
    Key.Key_SysReq: 'Snapshot',
    Key.Key_Insert: 'Insert',
    Key.Key_Delete: 'Delete',
    Key.Key_Help: 'Help',
    Key.Key_0: '0',
    Key.Key_1: '1',
    Key.Key_2: '2',
    Key.Key_3: '3',
    Key.Key_4: '4',
    Key.Key_5: '5',
    Key.Key_6: '6',
    Key.Key_7: '7',
    Key.Key_8: '8',
    Key.Key_9: '9',
    Key.Key_A: 'a',
    Key.Key_B: 'b',
    Key.Key_C: 'c',
    Key.Key_D: 'd',
    Key.Key_E: 'e',
    Key.Key_F: 'f',
    Key.Key_G: 'g',
    Key.Key_H: 'h',
    Key.Key_I: 'i',
    Key.Key_J: 'j',
    Key.Key_K: 'k',
    Key.Key_L: 'l',
    Key.Key_M: 'm',
    Key.Key_N: 'n',
    Key.Key_O: 'o',
    Key.Key_P: 'p',
    Key.Key_Q: 'q',
    Key.Key_R: 'r',
    Key.Key_S: 's',
    Key.Key_T: 't',
    Key.Key_U: 'u',
    Key.Key_V: 'v',
    Key.Key_W: 'w',
    Key.Key_X: 'x',
    Key.Key_Y: 'y',
    Key.Key_Z: 'z',
    Key.Key_Asterisk: 'asterisk',
    Key.Key_Plus: 'plus',
    Key.Key_Minus: 'minus',
    Key.Key_Period: 'period',
    Key.Key_Slash: 'slash',
    Key.Key_F1: 'F1',
    Key.Key_F2: 'F2',
    Key.Key_F3: 'F3',
    Key.Key_F4: 'F4',
    Key.Key_F5: 'F5',
    Key.Key_F6: 'F6',
    Key.Key_F7: 'F7',
    Key.Key_F8: 'F8',
    Key.Key_F9: 'F9',
    Key.Key_F10: 'F10',
    Key.Key_F11: 'F11',
    Key.Key_F12: 'F12',
    Key.Key_F13: 'F13',
    Key.Key_F14: 'F14',
    Key.Key_F15: 'F15',
    Key.Key_F16: 'F16',
    Key.Key_F17: 'F17',
    Key.Key_F18: 'F18',
    Key.Key_F19: 'F19',
    Key.Key_F20: 'F20',
    Key.Key_F21: 'F21',
    Key.Key_F22: 'F22',
    Key.Key_F23: 'F23',
    Key.Key_F24: 'F24',
    Key.Key_NumLock: 'Num_Lock',
    Key.Key_ScrollLock: 'Scroll_Lock',
}


if __name__ == "__main__":
    print(PyQtImpl)
    QVTKRenderWidgetConeExample()

I get no errors on my machine, but 2 windows instead of the intended 1:

MRE.py

from pyvistaqt import MainWindow, QtInteractor
from qtpy import QtWidgets


class Window(MainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Example')

        self.layout_ = QtWidgets.QVBoxLayout()

        self.container = QtWidgets.QFrame()
        self.container.setLayout(self.layout_)
        self.setCentralWidget(self.container)

        self.plotter = QtInteractor()
        self.plotter.add_axes()

        self.container.layout().addWidget(self.plotter)

        self.signal_close.connect(self.plotter.close)

app = QtWidgets.QApplication([])
window = Window()
window.show()
app.exec_()

When I uncomment

self._RenderWindow.SetWindowInfo(str(int(WId)))

The window is properly embedded, but the errors

QWindowsGLContext::makeCurrent: SetPixelFormat() failed (The pixel format is invalid.)
qt.qpa.backingstore: composeAndFlush: makeCurrent() failed

occur at every paint event

If I print the self._RenderWindow before and after setting the window info:

print(self._RenderWindow)
self._RenderWindow.SetWindowInfo(str(int(WId)))
print(self._RenderWindow)

The only thing that seems to have changed is the Window Id.

Before

vtkWin32OpenGLRenderWindow (000001E3ABE51800)       
  Debug: Off
  Modified Time: 52
  Reference Count: 1
  Registered Events: (none)
  Erase: On
  Window Name: Visualization Toolkit - Win32OpenGL #
  Position: (0, 0)
  Size: (0, 0)
  Mapped: 0
  ShowWindow: 1
  UseOffScreenBuffers: 0
  Double Buffered: 1
  DPI: 72
  TileScale: (1, 1)
  TileViewport: (0, 0, 1, 1)
  Borders: On
  Double Buffer: On
  Full Screen: Off
  Renderers:
    Debug: Off
    Modified Time: 44
    Reference Count: 1
    Registered Events: (none)
    Number Of Items: 0
  Stereo Capable Window Requested: No
  Stereo Render: Off
  Point Smoothing: Off
  Line Smoothing: Off
  Polygon Smoothing: Off
  Abort Render: 0
  Current Cursor: 0
  Desired Update Rate: 0.0001
  In Abort Check: 0
  NeverRendered: 1
  Interactor: 0000000000000000
  Swap Buffers: On
  Stereo Type: CrystalEyes
  Number of Layers: 1
  AlphaBitPlanes: On
  UseSRGBColorSpace: Off
  AnaglyphColorSaturation: 0.65
  AnaglyphColorMask: 4 , 3
  MultiSamples: 8
  StencilCapable: False
  ContextId: 0000000000000000
  Next Window Id: 0000000000000000
  Window Id: 0000000000000000

After

vtkWin32OpenGLRenderWindow (000001E3ABE51800) Debug: Off Modified Time: 52 Reference Count: 1 Registered Events: (none) Erase: On Window Name: Visualization Toolkit - Win32OpenGL # Position: (0, 0) Size: (0, 0) Mapped: 0 ShowWindow: 1 UseOffScreenBuffers: 0 Double Buffered: 1 DPI: 72 TileScale: (1, 1) TileViewport: (0, 0, 1, 1) Borders: On Double Buffer: On Full Screen: Off Renderers: Debug: Off Modified Time: 44 Reference Count: 1 Registered Events: (none) Number Of Items: 0 Stereo Capable Window Requested: No Stereo Render: Off Point Smoothing: Off Line Smoothing: Off Polygon Smoothing: Off Abort Render: 0 Current Cursor: 0 Desired Update Rate: 0.0001 In Abort Check: 0 NeverRendered: 1 Interactor: 0000000000000000 Swap Buffers: On Stereo Type: CrystalEyes Number of Layers: 1 AlphaBitPlanes: On UseSRGBColorSpace: Off AnaglyphColorSaturation: 0.65 AnaglyphColorMask: 4 , 3 MultiSamples: 8 StencilCapable: False ContextId: 0000000000000000 Next Window Id: 0000000000000000 Window Id: 0000000000160EC6

Is this what is supposed to happen? Do you think Qt is thinking we are trying to do things on the QMainWindow (here named Example), when we are really only trying to do them on the vtkWin32OpenGLRenderWindow window?

FWIW, pyvista's MainWindow class is very straightforward:

"""This module contains a Qt-compatible MainWindow class."""

from __future__ import annotations

from qtpy import QtCore
from qtpy.QtCore import Signal
from qtpy.QtWidgets import QMainWindow, QWidget


class MainWindow(QMainWindow):
    """Convenience MainWindow that manages the application."""

    signal_close = Signal()
    signal_gesture = Signal(QtCore.QEvent)

    def __init__(
        self,
        parent: QWidget | None = None,
        title: str | None = None,
        size: tuple[int, int] | None = None,
    ) -> None:
        """Initialize the main window."""
        QMainWindow.__init__(self, parent=parent)
        if title is not None:
            self.setWindowTitle(title)
        if size is not None:
            self.resize(*size)

    def event(self, event: QtCore.QEvent) -> bool:
        """Manage window events and filter the gesture event."""
        if event.type() == QtCore.QEvent.Gesture:  # pragma: no cover
            self.signal_gesture.emit(event)
            return True
        return super().event(event)

    def closeEvent(self, event: QtCore.QEvent) -> None:  # pylint: disable=invalid-name
        """Manage the close event."""
        self.signal_close.emit()
        event.accept()

[adam-grant-hendry]

@prabhuramachandran @wmvanvliet @larsoner Actually, now that I think of it, this error message does seem consistent with the changes from QGLWidget to QOpenGLWidget.

In particular, for PySide6 and PyQt6, QVTKRWIBase = 'QOpenGLWidget', and one of the notes states

Note: Avoid calling winId() on a QOpenGLWidget. This function triggers the creation of a native window, resulting in reduced performance and possibly rendering glitches.

You can see from the QtWidgets.QWidget docs:

also

Drawing directly to the QOpenGLWidget's framebuffer outside the GUI/main thread is possible by reimplementing paintEvent() to do nothing. The context's thread affinity has to be changed via QObject::moveToThread(). After that, makeCurrent() and doneCurrent() are usable on the worker thread. Be careful to move the context back to the GUI/main thread afterwards.

and

Adding a QOpenGLWidget into a window turns on OpenGL-based compositing for the entire window. In some special cases this may not be ideal, and the old QGLWidget-style behavior with a separate, native child window is desired. Desktop applications that understand the limitations of this approach (for example when it comes to overlaps, transparency, scroll views and MDI areas), can use QOpenGLWindow with QWidget::createWindowContainer(). This is a modern alternative to QGLWidget and is faster than QOpenGLWidget due to the lack of the additional composition step. It is strongly recommended to limit the usage of this approach to cases where there is no other choice. Note that this option is not suitable for most embedded and mobile platforms, and it is known to have issues on certain desktop platforms (e.g. macOS) too. The stable, cross-platform solution is always QOpenGLWidget.