目錄
字符型橫坐標代碼
折線圖代碼
運行
創建新類，繼承pg.PlotWidget，在新類中實現業務內容，重寫pg.PlotWidget中的wheelEvent方法并使用業務數據實現比較理想的縮放狀態。
字符型橫坐標代碼
class StrAxisItem(pg.AxisItem):def __init__(self,ticks,*args,**kwargs):pg.AxisItem.__init__(self,*args,**kwargs)self.x_values = [x[0] for x in ticks]self.x_strings = [x[1] for x in ticks]passdef tickStrings(self, values, scale, spacing):strings = []for v in values:vs = v*scaleif vs in self.x_values:vstr = self.x_strings[self.x_values.index(vs)]else:vstr = ''strings.append(vstr)return strings折線圖代碼
class LineGraphWidget(pg.PlotWidget):def __init__(self):super().__init__()self.init_data()passdef init_data(self):self.whole_df:pd.DataFrame = pd.DataFrame()self.color_one = (30,144,255)self.color_two = (138,43,226)self.color_three = (220,20,60)passdef set_data(self,df:pd.DataFrame):self.clear()self.addLegend()self.whole_df = dfx = df['x'].to_list()xTicks = df.loc[:, ['x', 'date']].valuesy_dict = {'one': df['one'].to_list(),'two': df['two'].to_list(),'three': df['three'].to_list()}one_curve = pg.PlotCurveItem(x=np.array(x),y=np.array(y_dict['one']),pen=pg.mkPen({'color':self.color_one}),connect='finite',name='one')two_curve = pg.PlotCurveItem(x=np.array(x),y=np.array(y_dict['two']),pen=pg.mkPen({'color':self.color_two}),connect='finite',name='two')three_curve = pg.PlotCurveItem(x=np.array(x),y=np.array(y_dict['three']),pen=pg.mkPen({'color':self.color_three}),connect='finite',name='three')horAxis = StrAxisItem(ticks=xTicks, orientation='bottom')self.setAxisItems({'bottom':horAxis})self.addItem(one_curve)self.addItem(two_curve)self.addItem(three_curve)self.vLine = pg.InfiniteLine(angle=90,movable=False)self.hLine = pg.InfiniteLine(angle=0,movable=False)self.label = pg.TextItem()self.addItem(self.vLine,ignoreBounds=True)self.addItem(self.hLine,ignoreBounds=True)self.addItem(self.label,ignoreBounds=True)self.vb = self.getViewBox()self.proxy = pg.SignalProxy(self.scene().sigMouseMoved, rateLimit=60, slot=self.pw_mouseMoved)self.enableAutoRange()passdef pw_mouseMoved(self, evt):pos = evt[0]if self.sceneBoundingRect().contains(pos):mousePoint = self.vb.mapSceneToView(pos)index = int(mousePoint.x())if index>=0 and index<len(self.whole_df):html_str = ''html_str += f"<br/>日期：{self.whole_df.loc[self.whole_df['x']==index].iloc[0]['date']}"html_str += f"<br/>one：{self.whole_df.loc[self.whole_df['x']==index].iloc[0]['one']}"html_str += f"<br/>two：{self.whole_df.loc[self.whole_df['x']==index].iloc[0]['two']}"html_str += f"<br/>three：{self.whole_df.loc[self.whole_df['x']==index].iloc[0]['three']}"self.label.setHtml(html_str)self.label.setPos(mousePoint.x(),mousePoint.y())passself.vLine.setPos(mousePoint.x())self.hLine.setPos(mousePoint.y())passdef wheelEvent(self,ev):if len(self.whole_df) <= 0:super().wheelEvent(ev)else:delta = ev.angleDelta().x()if delta == 0:delta = ev.angleDelta().y()s = 1.001 ** deltabefore_xmin, before_xmax = self.viewRange()[0]val_x = self.getViewBox().mapSceneToView(ev.position()).x()after_xmin = int(val_x - (val_x - before_xmin) // s)after_xmax = int(val_x + (before_xmax - val_x) // s)if after_xmin < 1:after_xmin = 0if after_xmin >= len(self.whole_df):after_xmin = max(len(self.whole_df) - 3, len(self.whole_df) - 1)if after_xmax < 1:after_xmax = min(len(self.whole_df) - 1, 1)if after_xmax >= len(self.whole_df):after_xmax = len(self.whole_df) - 1# print(after_xmin, after_xmax)df00 = self.whole_df.loc[(self.whole_df['x'] >= after_xmin) & (self.whole_df['x'] <= after_xmax)].copy()after_ymin = min(df00['one'].min(), df00['two'].min(), df00['three'].min())after_ymax = max(df00['one'].max(), df00['two'].max(), df00['three'].max())self.setXRange(after_xmin, after_xmax)self.setYRange(after_ymin, after_ymax)passpass運行
if __name__ == '__main__':df = pd.DataFrame(data={'date':['2020-01-01','2021-01-01','2022-01-01','2023-01-01','2024-01-01'],'one':[1,5,12,8,3],'two':[-9,2,4,8,-10],'three':[-1,5,8,10,-5]})df['x'] = range(len(df))app = QApplication([])pw = LineGraphWidget()pw.set_data(df.copy())pw.show()app.exec()pass
