Python Create a real circle button in pyqt5 [dupli

This question already has an answer here:

How to create a circular button in Qt Designer 1 answer

I try to create a circle button but in fact pyqt still creates a square button.All examples found just creates square buttons and put a round image in it but still when i try to hide background of the button it fails.I also try to add some hover function but this should work afterwords so you can skip it.My code is here:

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QAction
from PyQt5.QtGui import QPalette
# from video import VideoWindow
import sys

class HoverButton(QtWidgets.QToolButton):

    def __init__(self, parent=None):
        super(HoverButton, self).__init__(parent)
        self.setMouseTracking(True)

    def enterEvent(self,event):
        # print("Enter")
        self.setStyleSheet('''   
                                 border-image: url("images/exit.jpg") 10 10 2 2;
                                 border-top: 10px transparent;
                                 border-bottom: 10px transparent;
                                 border-right: 2px transparent;
                                 border-left: 2px transparent''')
        self.setGeometry(QtCore.QRect(1100, 550, 160, 161))

    def leaveEvent(self,event):
        self.setStyleSheet('''  
                                 border-image: url("images/exit.jpg") 10 10 2 2;
                                 border-top: 10px transparent;
                                 border-bottom: 10px transparent;
                                 border-right: 2px transparent;
                                 border-left: 2px transparent''')
        self.setGeometry(QtCore.QRect(1100, 550, 140, 141))

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(1371, 924)
        MainWindow.setAcceptDrops(True)
        self.button =  HoverButton(self)
        self.button.setGeometry(QtCore.QRect(1100, 550, 140, 141)) 
        self.button.setStyleSheet('''background: transparent;
                                 border-image: url("images/exit.jpg") 3 10 3 10;
                                 border-top: 3px transparent;
                                 border-bottom: 3px transparent;
                                 border-right: 10px transparent;
                                 border-left: 10px transparent;
                                 ''')
        self.button.setObjectName('button')
if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

Output:

One possible solution is to use setMask(), the advantage of this implementation is that the click event will only be for points inside the region.:

class HoverButton(QtWidgets.QToolButton):
    def __init__(self, parent=None):
        super(HoverButton, self).__init__(parent)
        self.setStyleSheet('''border-image: url("imagen.jpg")''')

    def resizeEvent(self, event):
        self.setMask(QtGui.QRegion(self.rect(), QtGui.QRegion.Ellipse))
        QtWidgets.QToolButton.resizeEvent(self, event)

Before:

After:

In your case the QRect() that is passed to QRegion must be adapted to the size of your image since the circular element is smaller than your image, a much easier way is to edit your image making the circle perfectly inscribed in your image as my image is.