class LossCurve(QGraphicsView):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setScene(QGraphicsScene(self))
        self.setDragMode(QGraphicsView.NoDrag)
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setRenderHint(QPainter.Antialiasing)

        self.chart = QChart()
        self.chart.setAcceptHoverEvents(True)
        self.chart.legend().hide()
        self.series = QLineSeries()
        self.chart.addSeries(self.series)

        self.x_axis = QValueAxis()
        self.x_axis.setLabelFormat("%i")
        self.y_axis = QValueAxis()

        self.chart.addAxis(self.x_axis, Qt.AlignBottom)
        self.series.attachAxis(self.x_axis)
        self.chart.addAxis(self.y_axis, Qt.AlignLeft)
        self.series.attachAxis(self.y_axis)

        self.scene().addItem(self.chart)

        self.x_legend = QGraphicsSimpleTextItem(self.chart)
        self.x_legend_text = '轮：'
        self.x_legend.setText(self.x_legend_text)
        self.y_legend = QGraphicsSimpleTextItem(self.chart)
        self.y_legend_text = '损失：'
        self.y_legend.setText(self.y_legend_text)

        self._callouts = []
        self._tooltip = Callout(self.chart)

        # self.series.clicked.connect(self.keep_callout) 
        self.series.hovered.connect(self.draw_tooltip)
        self.setMouseTracking(True)

    def enterEvent(self, event):
        print('enter........')

    def leaveEvent(self, event):
        print('leave........')