PyQtGraph - 获取误差条形图的图形效果

在本文中，我们将看到如何在 PyQtGraph 模块中获得误差条形图的图形效果。 PyQtGraph 是一个用于Python的图形和用户界面库，它提供了设计和科学应用程序中通常需要的功能。它的主要目标是提供用于显示数据（绘图、视频等）的快速交互式图形。误差条是数据可变性的图形表示，并在图表上用于指示报告测量中的误差或不确定性。它们给出了测量精确度的一般概念，或者相反，真实值可能与报告值相差多远。图形效果可以是阴影、不透明甚至颜色效果，用于增强误差线的外观。它可以在 setGraphicsEffect 方法的帮助下进行设置。
我们可以在下面给出的命令的帮助下创建一个绘图窗口并在其上创建误差条形图

# creating a pyqtgraph plot window
plt = pg.plot()

# creating a error bar item object
error = pg.ErrorBarItem(x=x, y=y, top=top,
                  bottom=bottom, beam=0.5)

In order to do this we use graphicsEffect method with the error bar item object
Syntax : error.graphicsEffect()
Argument : It takes no argument
Return : It returns QGraphicEffect object 
 

下面是实现

Python3

# importing Qt widgets
from PyQt5.QtWidgets import *
  
# importing system
import sys
  
# importing numpy as np
import numpy as np
  
# importing pyqtgraph as pg
import pyqtgraph as pg
from PyQt5.QtGui import *
from PyQt5.QtCore import *
  
from collections import namedtuple
  
  
class Window(QMainWindow):
  
    def __init__(self):
        super().__init__()
  
        # setting title
        self.setWindowTitle("PyQtGraph")
  
        # setting geometry
        self.setGeometry(100, 100, 600, 500)
  
        # icon
        icon = QIcon("skin.png")
  
        # setting icon to the window
        self.setWindowIcon(icon)
  
        # calling method
        self.UiComponents()
  
        # showing all the widgets
        self.show()
  
    # method for components
    def UiComponents(self):
  
        # creating a widget object
        widget = QWidget()
  
        # creating a label
        label = QLabel("Geeksforgeeks Error Bar plot")
  
        # setting minimum width
        label.setMinimumWidth(130)
  
        # making label do word wrap
        label.setWordWrap(True)
  
        # setting configuration options
        pg.setConfigOptions(antialias=True)
  
        # creating x-axis values
        x = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
  
        # creating y-axis values
        y = np.array([5, 4, 3, 2, 5, 6, 4, 8, 9, 8])
  
        # creating upper bound values
        top = np.array([2, 2, 2, 2, 2, 2, 2, 2, 2, 2])
  
        # creating lower bound values
        bottom = np.array([2, 2, 2, 2, 2, 2, 2, 2, 2, 2])
  
        # creating a plot window
        plt = pg.plot()
  
        # creating a error bar item
        error = pg.ErrorBarItem(beam=0.5)
  
        # setting data to error bar item
        error.setData(x=x, y=y, top=top, bottom=bottom)
  
        # adding error bar item to the plot window
        plt.addItem(error)
  
        # plotting the data on plot window
        plt.plot(x, y, symbol='o', pen={'color': 0.8, 'width': 2})
  
        # Creating a grid layout
        layout = QGridLayout()
  
        # minimum width value of the label
        label.setMinimumWidth(130)
  
        # setting this layout to the widget
        widget.setLayout(layout)
  
        # adding label in the layout
        layout.addWidget(label, 1, 0)
  
        # plot window goes on right side, spanning
        # 3 rows
        layout.addWidget(plt, 0, 1, 3, 1)
  
        # setting this widget as central widget
        # of the main widow
        self.setCentralWidget(widget)
  
        # creating a QGraphicsDropShadowEffect object
        shadow = QGraphicsDropShadowEffect()
  
        # setting blur radius
        shadow.setBlurRadius(15)
  
        # setting offset
        shadow.setOffset(10)
  
        # setting color
        shadow.setColor(Qt.white)
  
        # setting graphic effect to the error bar
        error.setGraphicsEffect(shadow)
  
        # getting graphic effect of the error bar item
        value = error.graphicsEffect()
  
        # setting text to the label
        label.setText("Graphic Effect : " + str(value))
  
  
# create pyqt5 app
App = QApplication(sys.argv)
  
# create the instance of our Window
window = Window()
  
# start the app
sys.exit(App.exec())

输出 ：