QPainter::begin: Paint device returned engine == 0, type: 1

[KIMIA]

Hi Guys
I have a QVTKRenderWindowInteractor and wants to draw line on it.
I pass the QVTKRenderWindowInteractor object to my painter but when i run I got " Painter not active".
Here is my method :

# obj is type of QVTKRenderWindowInteractor
def draw_line(self, obj):

    painter = QPainter(obj)

    # painter.begin(obj)

    painter.setRenderHint(QPainter.Antialiasing)

    painter.setPen(QtCore.Qt.red)

    painter.setBrush(QtCore.Qt.white)

    painter.drawLine(400, 100, 100, 100)

Thank You.

[JonB]

@KIMIA said in QPainter::begin: Paint device returned engine == 0, type: 1:
Not my area, but your code is run inside some paintEvent(), right?

I think your error message comes from QPainter::isActive() returning false. After one of painter = QPainter(obj) or painter.begin(obj) it needs to return true, but you're saying it's still false?