PyQt5: ¿cómo obtener una imagen cuadrada recortada de una imagen rectangular?

# importing libraries
from PyQt5.QtCore import * 
from PyQt5.QtGui import * 
from PyQt5.QtWidgets import *
  
# function to alter image
def mask_image(imgdata, imgtype ='png', size = 64):
  
    # Load image
    image = QImage.fromData(imgdata, imgtype)
  
    # convert image to 32-bit ARGB (adds an alpha 
    # channel ie transparency factor):
    image.convertToFormat(QImage.Format_ARGB32)
  
    # Crop image to a square:
    imgsize = min(image.width(), image.height())
    rect = QRect(
        (image.width() - imgsize) / 2,
        (image.height() - imgsize) / 2,
        imgsize,
        imgsize,
    )
    image = image.copy(rect)
  
    # Create the output image with the 
    # same dimensions and an alpha channel
    # and make it completely transparent:
    out_img = QImage(imgsize, imgsize, QImage.Format_ARGB32)
    out_img.fill(Qt.transparent)
  
    # Create a texture brush and paint a circle
    # with the original image onto
    # the output image:
    brush = QBrush(image)
  
    # Paint the output image
    painter = QPainter(out_img)
    painter.setBrush(brush)
  
    # Don't draw an outline
    painter.setPen(Qt.NoPen)
  
    # drawing square
    painter.drawRect(0, 0, imgsize, imgsize)
  
    # closing painter event
    painter.end()
  
    # Convert the image to a pixmap and rescale it.
    pr = QWindow().devicePixelRatio()
    pm = QPixmap.fromImage(out_img)
    pm.setDevicePixelRatio(pr)
    size *= pr
    pm = pm.scaled(size, size, Qt.KeepAspectRatio, 
                               Qt.SmoothTransformation)
  
    # return back the pixmap data
    return pm
  
  
class Window(QWidget):
  
    """Simple window that shows our masked image and text label."""
    def __init__(self):
        super().__init__()
  
        # setting up the geometry
        self.setGeometry(100, 100, 600, 400)
  
        # image path
        imgpath = "image.png"
  
        # loading image
        imgdata = open(imgpath, 'rb').read()
  
        # calling the function
        pixmap = mask_image(imgdata)
  
        # creating label
        self.ilabel = QLabel(self)
  
        # putting image on label
        self.ilabel.setPixmap(pixmap)
  
        # moving the label
        self.ilabel.move(240, 180)
  
        # another label to put text
        self.tlabel = QLabel('This is croped image', self)
        self.tlabel.move(200, 250)
  
  
  
# main function
if __name__ == '__main__':
    import sys
    from PyQt5.QtWidgets import QApplication
  
    # app created
    app = QApplication(sys.argv)
    w = Window()
    w.show()
  
    # begin the app
    sys.exit(app.exec_())