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QAxWidget glitches when resizing GUI window

I am currently exploring the possibilities of displaying and working with PowerPoint presentations in a GUI using PyQt5/PyQt6 and Python. For that I found the most promising solution to be using a QAxWidget. Loading and displaying the pptx-file works fine, but unfortunately I noticed glitches when resizing the window of the GUI.
As a minimal example I used the following tutorial from the official Qt docs:
https://doc.qt.io/qtforpython/examples/example_axcontainer__axviewer.html?highlight=qaxwidget
After the QAxWidget()-initialization i just added the following line:
self.axWidget.setControl(r"C:\path\to\file\presentation.pptx")
Full code (taken from: https://doc.qt.io/qtforpython/examples/example_axcontainer__axviewer.html?highlight=qaxwidget):
# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
"""PySide6 Active Qt Viewer example"""
import sys
from PyQt5.QtWidgets import qApp
from PySide6.QtAxContainer import QAxSelect, QAxWidget
from PySide6.QtGui import QAction
from PySide6.QtWidgets import (QApplication, QDialog,
QMainWindow, QMessageBox, QToolBar)
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
toolBar = QToolBar()
self.addToolBar(toolBar)
fileMenu = self.menuBar().addMenu("&File")
loadAction = QAction("Load...", self, shortcut="Ctrl+L", triggered=self.load)
fileMenu.addAction(loadAction)
toolBar.addAction(loadAction)
exitAction = QAction("E&xit", self, shortcut="Ctrl+Q", triggered=self.close)
fileMenu.addAction(exitAction)
aboutMenu = self.menuBar().addMenu("&About")
aboutQtAct = QAction("About &Qt", self, triggered=qApp.aboutQt)
aboutMenu.addAction(aboutQtAct)
self.axWidget = QAxWidget()
self.axWidget.setControl(r"C:\path\to\file\presentation.pptx")
self.setCentralWidget(self.axWidget)
def load(self):
axSelect = QAxSelect(self)
if axSelect.exec() == QDialog.Accepted:
clsid = axSelect.clsid()
if not self.axWidget.setControl(clsid):
QMessageBox.warning(self, "AxViewer", f"Unable to load {clsid}.")
if __name__ == '__main__':
app = QApplication(sys.argv)
mainWin = MainWindow()
availableGeometry = mainWin.screen().availableGeometry()
mainWin.resize(availableGeometry.width() / 3, availableGeometry.height() / 2)
mainWin.show()
sys.exit(app.exec())
When resizing the window of the GUI, there appear some glitches underneath:
An animation that shows the result while resizing:
Unfortunately I haven't found many resources I could use where a QAxWidget is used in combination with Python to figure this out myself. That's why I'm here to ask if anyone out there might have a solution for getting rid of those glitches.

I got rid of the glitches by installing an event filter to the QAxWidget using self.axWidget.installEventFilter(self).
This will call the eventFilter()-method of the QMainWindow which I set up like this: (ReportDefinitionTool is the subclass of QMainWindow here.)
def eventFilter(self, widget: QWidget, event: QEvent):
if event.type() == QEvent.Resize and widget is self.pptx_axwidget:
self.pptx_axwidget.setFixedHeight(int(self.pptx_axwidget.width() / 16 * 9))
return super(ReportDefinitionTool, self).eventFilter(widget, event)
Since the PowerPoint-presentation is displayed in a 16:9 format, this will make sure the QAxWidget does only occupy this space. The glitchy space from the initial question came from the unused space of the QAxWidget.

Widgets are not displayed

I'm currently doing a tutorial on how to create GUI apps from a book called "Modern PyQt" by Joshua Willman and I'm stuck right out of the gate:
I've copy pasted a basic code snippet from the book and tried to tweak it bit by bit instead of reading a bunch of text without any practical trial and error. I can display a window and adjust it's size and properties, but when I try to attach other widgets to the main window, they just don't show up.
Here's what I've got so far:
# First practical example from the book: Pomodoro time manager
import sys
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton
from PyQt5.QtGui import QIcon
class Pomodoro(QWidget):
def __init__(self): # Create default constructor
super().__init__()
self.initializeUI()
def initializeUI(self):
"""Initialize the window and display its contents to the screen."""
self.setGeometry(int((SCREEN_WIDTH-WINDOW_WIDTH)/2),int((SCREEN_HEIGHT-WINDOW_HEIGHT)/2),WINDOW_WIDTH,WINDOW_HEIGHT) # x,y,w,h
self.setWindowTitle('Bortism')
# self.setWindowIcon(QIcon("Borticon.png"))
self.button1 = QPushButton()
self.button1.setText('Button')
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
WINDOW_WIDTH, WINDOW_HEIGHT = 1000,600
SCREEN_X, SCREEN_Y, SCREEN_WIDTH, SCREEN_HEIGHT = app.desktop().screenGeometry().getRect()
window = Pomodoro()
sys.exit(app.exec_())

For a widget to be shown as part of another then the requirement is that the first is the child of the second. This can be done by passing the parent or by using a layout (which is also passed to it by the parent). So in your case you must change to:
self.button1 = QPushButton(self)

PyQt5 buttons not connecting

I am trying to build a simple GUI using PyQT5, with 3 buttons to open file browsers and one more to run processing with the selected files, but I can't get my buttons to connect to the functions needed to carry this out.
In the Ctrl class, the _connect_signals function doesn't seem to be calling _input_select. Can anyone help me figure out why?
import sys
# Import QApplication and the required widgets from PyQt5.QtWidgets
from PyQt5.QtWidgets import QApplication
from PyQt5.QtWidgets import QMainWindow
from PyQt5.QtWidgets import QPushButton
from PyQt5.QtWidgets import QVBoxLayout
from PyQt5.QtWidgets import QWidget
from PyQt5.QtWidgets import QFileDialog
# Create a subclass of QMainWindow to setup the calculator's GUI
class UI(QMainWindow):
"""App's View (GUI)."""
def __init__(self):
"""View initializer."""
super().__init__()
# Set some main window's properties
self.setFixedSize(300, 150)
# Set the central widget and the general layout
self.generalLayout = QVBoxLayout()
self._centralWidget = QWidget(self)
self.setCentralWidget(self._centralWidget)
self._centralWidget.setLayout(self.generalLayout)
# Create the buttons
self._create_buttons()
def _create_buttons(self):
"""Create the buttons."""
self.buttons = {}
buttons_layout = QVBoxLayout()
# Button text | position on the QVBoxLayout
buttons = {
"Select input file...": 0,
"Select config file...": 1,
"Select output file...": 2,
"Run": 3,
}
# Create the buttons and add them to the grid layout
for btnText, pos in buttons.items():
self.buttons[btnText] = QPushButton(btnText)
buttons_layout.addWidget(self.buttons[btnText], pos)
# Add buttons_layout to the general layout
self.generalLayout.addLayout(buttons_layout)
# Create a Controller class to connect the GUI and the model
class Ctrl:
"""App's Controller."""
def __init__(self, setup, view):
"""Controller initializer."""
self._view = view
self._setup = setup
# Connect signals and slots
self._connect_signals()
def _input_select(self): # Not being called
print("input selection")
options = QFileDialog.Options()
file_select, _ = QFileDialog.getOpenFileNames(
self,
'Select Input File...',
'',
'CSV Files (*.csv);;All Files (*)',
options=options
)
if file_select:
self._setup["input"] = file_select
def _connect_signals(self):
"""Connect signals and slots."""
self._view.buttons["Select input file..."].clicked.connect(self._input_select) # Not working!
# Client code
def main():
"""Main function."""
# Create an instance of `QApplication`
app = QApplication(sys.argv)
# Show the app's GUI
view = UI()
view.show()
setup = {}
# Create instance of the controller
Ctrl(setup=setup, view=view)
# Execute app's main loop
sys.exit(app.exec_())
if __name__ == "__main__":
main()
In case it helps, I started out by butchering this example code from a Real Python tutorial, but must have broken it along the way.

The problem is that you are not keeping any persistent reference to the Ctrl() instance you are creating. This results in python garbage collecting it as soon as the instance is created.
To solve the issue, just assign it to a variable:
def main():
"""Main function."""
# Create an instance of `QApplication`
app = QApplication(sys.argv)
# Show the app's GUI
view = UI()
view.show()
setup = {}
# Create instance of the controller
ctrl = Ctrl(setup=setup, view=view)
# Execute app's main loop
sys.exit(app.exec_())
Some considerations:
while separating logic from interface is usually good practice, it's a concept that needs to be used with care, as sometimes it only makes things more complex than they should be. Most of the times (especially with simple programs), it only makes a bigger codebase without giving any actual benefit: it's harder to read and to debug, and you'll probably end up continuously switching from the logic parts and the ui parts of your code;
your code shows one of the drawback of that concept: when you create the file dialog, you're using self, but in that case it refers to the Ctrl instance, while the argument should be the UI instance instead (which will result in a crash, as Qt will get an unexpected argument type); you can use self._view instead, but, as said, the whole separation in this case just makes things unnecessarily complex;
using strings for dictionary keys that refer to internal objects is rarely a good idea (especially when using long descriptive strings like you did);
when importing more than one element from a module, it's usually better to group them instead of using single line imports: it makes the code tidier and easier to read and inspect: from PyQt5.QtWidgets import (QApplication, QMainWindow, QPushButton, QVBoxLayout, QWidget, QFileDialog)

PyQt resize QMovie with proper anti-aliasing

I created a QLabel and set it's movie to a QMovie object with an animated gif. Then in the resizeEvent of my app I resize and move the label, so that it is centered/fit to the layout. This works fine but the movie has a lot of fine lines which get totally garbled in the resize operation, it seems there is no anti-aliasing. So either I am using the wrong resize method, or I need to set anti-aliasing somewhere right? There is nothing in the QMovie or QLabel documentation to suggest how to do this. I did read that the QMovie is inherited from a QImageReader, though that too has no property for anti-aliasing that I could find.
EDIT
I did somewhat get this to work, but it's still not quite right. I found that QMovie has a setScaledSize method which actually scales the underlying QImageViewer. Then I just have the label adjust to it's contents, namely the movie. Using the following code I am able to resize the movie with proper anti-aliasing, however it is quite "jumpy" and "flickery" during resize so obviously I'm not doing this quite "right". Also it somehow loses it's aspect ratio sometimes. Still looking for the correct way to do this... Maybe a QLabel is the wrong way to go?
Here's a working example
import sys
from PyQt4 import QtGui
class MovieTest(QtGui.QDialog):
def __init__(self):
super(MovieTest, self).__init__()
layout = QtGui.QVBoxLayout()
self.setLayout(layout)
self.loading_lbl = QtGui.QLabel()
self.loading_lbl.setSizePolicy(QtGui.QSizePolicy.Ignored, QtGui.QSizePolicyIgnored)
self.loading_lbl.setScaledContents(True)
layout.addWidget(self.loading_lbl)
loading_movie = QtGui.QMovie("loading-radial_loop.gif") # some gif in here
self.loading_lbl.setMovie(loading_movie)
loading_movie.start()
self.setGeometry(50,50,100,100)
self.setMinimumSize(10,10)
def resizeEvent(self, event):
rect = self.geometry()
size = min(rect.width(), rect.height())
movie = self.loading_lbl.movie()
movie.setScaledSize(QtCore.QSize(size, size))
self.loading_lbl.adjustSize()
def main():
app = QtGui.QApplication(sys.argv)
ex = MovieTest()
ex.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()

Ok I have this figured out now, with just a few tweaks to the code in my edited post. The secret is in keeping the label the full size of it's parent rect (in this case the size of the whole layout) and then scaling the movie within the label. Essentially you are internally scaling the movie, instead of having it automatically fill the contents of the label. From what I can tell this changes around the order of operations a bit and allows the movie to scale itself on render, instead of rendering the frame and then scaling it to the label size.
Working code:
import sys
from PyQt4 import QtGui, QtCore
class MovieTest(QtGui.QDialog):
def __init__(self):
super(MovieTest, self).__init__()
layout = QtGui.QVBoxLayout()
self.setLayout(layout)
self.loading_lbl = QtGui.QLabel()
self.loading_lbl.setStyleSheet('border: 1px solid red') # just for illustration
self.loading_lbl.setAlignment(QtCore.Qt.AlignCenter)
layout.addWidget(self.loading_lbl)
loading_movie = QtGui.QMovie("loading-radial_loop.gif")
self.loading_lbl.setMovie(loading_movie)
loading_movie.start()
self.setGeometry(50,50,100,100)
self.setMinimumSize(10,10)
def resizeEvent(self, event):
rect = self.geometry()
size = QtCore.QSize(min(rect.width(), rect.height()), min(rect.width(), rect.height()))
movie = self.loading_lbl.movie()
movie.setScaledSize(size)
def main():
app = QtGui.QApplication(sys.argv)
ex = MovieTest()
ex.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()

Qt - keep reference of widget in Python

In reference to a previous question, I need some help with keeping references in my application.
First a snippet from my code.
from PyQt4 import QtGui
import os, os.path
import sys
class mainWindowHandler():
equationEditor = []
_listview = None
_window = None
def __init__(self):
return
def showAddEquation(self):
"""Creates a new instance of the dynamic editor for adding an equation"""
#create a horizontal split layout
window = QtGui.QWidget()
layout = QtGui.QHBoxLayout()
current = len(self.equationEditor) - 1
de = QtGui.QPushButton(str(current))
self.equationEditor.append(de)
de.clicked.connect(self.clicked)
#fill list view with items from equation collection
listview = QtGui.QListWidget()
for equation in self.equationEditor:
item = QtGui.QListWidgetItem()
item.setText(equation.text())
listview.addItem(item)
layout.addWidget(listview)
layout.addWidget(de)
window.setWindowTitle("Equation {}".format(str(current))
window.setLayout(layout)
self._window = window
self._listview = listview
window.show()
return window
def clicked(self):
"""Method for handling the button events in the solver settings\n
signal = the button hit\n"""
return self.showAddEquation()
if __name__ == "__main__":
path = os.path.dirname(os.path.abspath(__file__))
app = QtGui.QApplication(sys.argv)
ewh = mainWindowHandler()
window = ewh.showAddEquation()
sys.exit(app.exec_())
The application will (later) create a window that allows the manipulation of certain settings - in my code example represented by the QPushButton. These settings are later written to a txt-file, but until then I save them in form of there widget. I simply add the widget to a collection and recall them from there. That works well on the Python-level.
Now, I have a button that creates a new instance of the window from inside of the window itself. That works too. But only until the third instance. At that point I loose the reference to my QPushButton on the Qt-level. I get the
wrapped C/C++ object of type `QPushButton` has been deleted
error when trying to retrieve the buttons from my collection (equationEditor). In Python they are still there, but obviously the corresponding Qt-objects where destroyed because I somewhere mishandled the references.
Can someone point out a better solution or how I can keep the references?
Thanks...
Edit:
As there seem to be some confusions I will try to explain the functionality a bit more in detail.
The program starts and creates a window "Equation 1" with a QListViewand a QPushButton "1". In the list view all available QPushButton are listed (at start only 1 item). In my actual program the QPushButton is QWidget with some text fields and the QPushButton.
If the user clicks "1" then the button "1" should disappear and a new instance of QPushButton named "2" should appear at the position of "1". Additionally, the listview should now hold two items "1" and "2" and the window should have the title "Equation 2". If it is a new window or the same as before with new contents is not relevant. Both variants would be okay. The former is the way it is implemented at the moment. Visible should by only one window at a time.
All instances of QPushButton should by collected in a small list (called equationEditor) to keep them in the memory. In my actual program this is used for saving all changes made in the widgets without writing the changes to a temp file.
Later, if the user selects item "1" in the QListView then the current visible QPushButton should be replaced by the QPushButton "1" (from the collection equationEditor) or if he selects the second item the QPushButton "2" should be shown.
Why?
The widget that will be used later contains a lot of editable data. As the user could edit that at any time it is easier to keep the widgets in memory without showing them instead of repopulating all the data again. As soon as the user selects one in the QListView the corresponding widget should be shown in the window so that he can edited the data in the widget again.

It's quite hard to understand what exactly you're trying to do. Looking at your code I wonder why it is even working twice before failing.
Btw. I just saw, that there is a quite accurate description of why it's failing in the previous post, given by Schollii
Anyways, I think you should make a new class for the equation window. The main class can then keep track of all opened windows in the equationEditor list. It can also add the values of the other opened windows to a new one, once created.
Here is how it would look like
from PyQt4 import QtGui
import os, os.path
import sys
class ShowAddEquation(QtGui.QWidget):
"""Creates a new instance of the dynamic editor for adding an equation"""
def __init__(self,parent=None):
super(ShowAddEquation, self).__init__(parent=parent)
#create a horizontal split layout
layout = QtGui.QHBoxLayout()
self.current = 0
self.de = QtGui.QPushButton(str(self.current))
self.listview = QtGui.QListWidget()
layout.addWidget(self.listview)
layout.addWidget(self.de)
self.setWindowTitle("Equation Editor")
self.setLayout(layout)
self.show()
def setCurrent(self, current):
self.current=current
self.de.setText(str(self.current))
class mainWindowHandler():
equationEditor = []
def __init__(self):
return
def clicked(self):
se = ShowAddEquation()
self.equationEditor.append(se)
se.de.clicked.connect(self.clicked)
current = len(self.equationEditor) - 1
se.setCurrent(current)
for equation in self.equationEditor:
item = QtGui.QListWidgetItem()
item.setText(str(equation.current))
se.listview.addItem(item)
if __name__ == "__main__":
path = os.path.dirname(os.path.abspath(__file__))
app = QtGui.QApplication(sys.argv)
ewh = mainWindowHandler()
ewh.clicked()
sys.exit(app.exec_())

So, after understanding the approach given in the first answer I have solved my problem. Here is the working code
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 3 14:31:15 2016
"""
from PyQt4 import QtGui
from PyQt4 import QtCore
import os, os.path
import sys
class mainWindowHandler():
equationEditor = []
_listview = None
_window = None
def __init__(self):
return
def showAddEquation(self):
"""Creates a new instance of the dynamic editor for adding an equation"""
#create a horizontal split layout
self._window = QtGui.QWidget()
layout = QtGui.QHBoxLayout()
self._listview = QtGui.QListWidget()
layout.addWidget(self._listview)
self._listview.clicked[QtCore.QModelIndex].connect(self.changed)
self._window.setLayout(layout)
#populate the right side of the layout with a button
self.clicked()
self._window.show()
return self._window
def clicked(self):
"""Make a new button instance and add it to the window and the collection"""
window = self._window
layout = window.layout()
current = len(self.equationEditor) - 1
de = QtGui.QPushButton(str(current))
self.equationEditor.append(de)
de.clicked.connect(self.clicked)
#close the currently shown button
item = layout.takeAt(1)
if item is not None:
item.widget().close()
layout.addWidget(de)
#fill list view with items from material collection
item = QtGui.QListWidgetItem()
item.setText(de.text())
self._listview.addItem(item)
self._window.setWindowTitle("Equation Editor {}".format(str(current)))
def changed(self, index):
"""hide the object on the right side of the layout and show the button at position index in the collection"""
layout = self._window.layout()
item = layout.takeAt(1)
item.widget().close()
# insert the selected button from the collection
de = self.equationEditor[index.row()]
layout.insertWidget(1, de)
self._window.setWindowTitle("Equation Editor {}".format(str(index.row() - 1)))
de.show()
if __name__ == "__main__":
path = os.path.dirname(os.path.abspath(__file__))
app = QtGui.QApplication(sys.argv)
ewh = mainWindowHandler()
window = ewh.showAddEquation()
sys.exit(app.exec_())