def paintEvent(self, event):
        """QWidget.paintEvent() implementation
        Draw markers
        """
        painter = QPainter(self)
        painter.fillRect(event.rect(), self.palette().color(QPalette.Window))

        block = self._qpart.firstVisibleBlock()
        blockBoundingGeometry = self._qpart.blockBoundingGeometry(block).translated(self._qpart.contentOffset())
        top = blockBoundingGeometry.top()
        bottom = top + blockBoundingGeometry.height()

        for block in qutepart.iterateBlocksFrom(block):
            height = self._qpart.blockBoundingGeometry(block).height()
            if top > event.rect().bottom():
                break
            if block.isVisible() and \
               bottom >= event.rect().top():
                if block.blockNumber() in self._qpart.lintMarks:
                    msgType, msgText = self._qpart.lintMarks[block.blockNumber()]
                    pixMap = self._lintPixmaps[msgType]
                    yPos = top + ((height - pixMap.height()) / 2)  # centered
                    painter.drawPixmap(0, yPos, pixMap)

                if self.isBlockMarked(block):
                    yPos = top + ((height - self._bookmarkPixmap.height()) / 2)  # centered
                    painter.drawPixmap(0, yPos, self._bookmarkPixmap)

            top += height