Pyqt5: Painting Using Events

I am new on PyQt I am working on a project on which I should implement a feature that make the user able to draw a digit using the mouse (digit recognition system). So what I want

Solution 1:

Python is sensitive to uppercase and lowercase so be more careful, the method is called paintEvent.

Also you should not call paintEvent directly, you must use the function update(), this method will internally call paintEvent().

But even correcting that error your problem is not solved, if you want to draw a path it is advisable to use QPainterPath as this stores the strokes.

class Drawer(QWidget):
    newPoint = pyqtSignal(QPoint)
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)
        self.path = QPainterPath()    

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.drawPath(self.path)

    def mousePressEvent(self, event):
        self.path.moveTo(event.pos())
        self.update()

    def mouseMoveEvent(self, event):
        self.path.lineTo(event.pos())
        self.newPoint.emit(event.pos())
        self.update()

    def sizeHint(self):
        return QSize(400, 400)

class MyWidget(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)
        self.setLayout(QVBoxLayout())
        label = QLabel(self)
        drawer = Drawer(self)
        drawer.newPoint.connect(lambda p: label.setText('Coordinates: ( %d : %d )' % (p.x(), p.y())))
        self.layout().addWidget(label)
        self.layout().addWidget(drawer)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = MyWidget()
    w.show()
    sys.exit(app.exec_())

Screenshot: