PyQt5 QScrollBar – Set Reverse Control Property

PyQt5 is a powerful GUI (Graphical User Interface) toolkit. The PyQt5 QScrollBar widget is used to control the value of a variable by sliding a knob along a track. In this tutorial, we will learn how to set the reverse control property of a QScrollBar widget in PyQt5.

What is the reverse control property?

The reverse control property of a QScrollBar widget determines the direction of the control. By default, the control moves from minimum value to maximum value when it is slid along the track. When the reverse control property is set to True, the direction is reversed and the control moves from maximum value to minimum value.

Setting the reverse control property of a QScrollBar widget

To set the reverse control property of a QScrollBar widget in PyQt5, we can use the setInvertedAppearance() method and pass True as its argument.

scroll_bar = QScrollBar()
scroll_bar.setInvertedAppearance(True)

The above code creates a QScrollBar widget and sets its reverse control property to True.

Example

Here is a complete example that demonstrates how to set the reverse control property of a QScrollBar widget in PyQt5:

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QScrollBar


class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):

        scroll_bar = QScrollBar(self)
        scroll_bar.setInvertedAppearance(True)
        scroll_bar.resize(30, 200)
        scroll_bar.move(50, 50)

        self.setGeometry(300, 300, 250, 150)        
        self.setWindowTitle('QScrollBar Reverse Control')    
        self.show()


if __name__ == '__main__':

    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

In the above example, we create a QScrollBar widget and set its reverse control property to True. We then resize and move the widget on the window. Finally, we set the window geometry, title, and show the window.

Conclusion

In this tutorial, we learned how to set the reverse control property of a QScrollBar widget in PyQt5. By setting this property, we can control the direction of the widget control. This is a powerful feature that can be useful in many applications.