[FIXED] Pyqtgraph's PlotWidget doesn't show correctly

Issue

I've been trying to embed a graph into my application using pyqtgraph's PlotWidget. It seemed simple enough while following this tutorial. I have managed to show a graph well enough, the problem is that the graph looks broken. Here is an image of the most simple app I could make to show the problem:

Bugged graph app

I used the following code:

from PyQt5.QtWidgets import (QMainWindow, QApplication)
from pyqtgraph import PlotWidget
from PyQt5 import uic
import sys

class UI(QMainWindow):
            
    def __init__(self):
        super(UI, self).__init__()
        
        # Load the ui file
        uic.loadUi("test.ui", self)
        
        self.GraphWidget = self.findChild(PlotWidget,"GraphWidget")

        self.GraphWidget.showGrid(x=True, y=True)
        
        # Show The App
        self.show()

            
            
# Initialize The App
def main():
    app = QApplication(sys.argv)
    UIWindow = UI()
    app.exec_()
      
    
if __name__ == '__main__':
   main()

The steps I followed in Qt Designer were:

1. Add QWidget to the main window
2. Promote it to PlotWidget, setting the header file to pyqtgraph
3. Save test.ui file

When I tried embedding the graph into my program, the same bug appeared. That's why I have made this simple example to showcase it.

Some notes about my setup:

• I'm using windows 11 (perhaps it's this, but I can't test it in another computer).
• Python version 3.9.7
• Qt version 5.9.7
• Pyqtgraph version 0.11.0
• I'm using Anaconda, and to test this I created a clean environment and installed just the necessary packages.

I would appreciate any help with this.

EDIT

The test.ui file contains the following:

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>480</width>
    <height>419</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>
     <widget class="PlotWidget" name="GraphWidget" native="true"/>
    </item>
   </layout>
  </widget>
 </widget>
 <customwidgets>
  <customwidget>
   <class>PlotWidget</class>
   <extends>QWidget</extends>
   <header>pyqtgraph</header>
   <container>1</container>
  </customwidget>
 </customwidgets>
 <resources/>
 <connections/>
</ui>

Solution

As @titusjan pointed out, I do have two monitors with different scaling factors. Running the program with the same scaling factors or with just one monitor fixed the problem.

There also are some workarounds in the issue thread @titusjan provided.

Answered By - Fernando Gómez de la Varga