Image pan and zoom in and out from center are not working 【New 2021】

[mu0gua]

FROM： #13 (comment)

I also encountered the same problem

I tried to solve him in a bad way

filepath:  roLabelImg-master\libs\canvas.py    line: 159

if Qt.LeftButton & ev.buttons():
            self.MouseMove = ev.pos() - self.preMousePosition
            self.preMousePosition = ev.pos() 
            self.prevPoint = self.pos() + self.MouseMove
            self.move(self.prevPoint)
                

filepath:  roLabelImg-master\libs\canvas.py    line: 225

self.preMousePosition = ev.pos()

If you have any good plan, please contact me, thank you very much