QPainter in PyQt

[luishengjie]

Hi guys, I kinda new with ptqt and seem to have the following error when I try to create a simple QPaint program. Does anyone know how can I "active" my Painter? Help is much appreciated. Thanks you in advance.
QPainter::setRenderHint: Painter must be active to set rendering hints
QPainter::setPen: Painter not active

def paintEvent(self, event = None):
paint = QPainter()
paint.setRenderHint(QPainter.Antialiasing)
paint.setPen(QtGui.QPen(QtGui.QColor(Qt.green)))
paint.drawEllipse(300,300,70,70)

[tilsitt]

Hi,

To be active, your painter must be connected to a device, either by giving it as argument during construction or by calling QPainter::begin().

[luishengjie]

def paintEvent(self, event = None):
paint = QPainter()
paint.begin()
paint.setRenderHint(QPainter.Antialiasing)
paint.setPen(QtGui.QPen(QtGui.QColor(Qt.green)))
paint.drawEllipse(300,300,70,70)
paint.end()

I initially had the paint.begin() statement however when i implement that statement I would have the following error:
TypeError: QPainter.begin(QPaintDevice): not enough arguments

[tilsitt]

The error is giving you the answer: begin() takes a QPaintDevice (e.g. a widget) as argument.

[luishengjie]

What is considered as a QPaintEvent argument?

[SGaist]

Hi,

My PyQt is a bit rusted but IIRC you need something like:

@
paint = QPainter(self)
@

Otherwise you are trying to paint on nothing so it won't work.

Hope it helps