PyQtGraph - 设置条形图的不透明度级别

在本文中，我们将看到如何在 PyQtGraph 模块中设置条形图的不透明度级别。 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，其次是提供帮助快速应用程序开发的工具（例如，Qt Designer 中使用的属性树）。条形图或条形图是一种图表或图形，它用矩形条显示分类数据，矩形条的高度或长度与其所代表的值成正比。条形可以垂直或水平绘制。垂直条形图有时也称为柱形图。不透明度是衡量电磁或其他类型辐射（尤其是可见光）不可穿透性的指标。在辐射传输中，它描述了辐射在介质中的吸收和散射，例如等离子体、电介质、屏蔽材料、玻璃等。

我们可以在下面给出的命令的帮助下创建一个绘图窗口和条形图

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

# creating a bar graph of green color
bargraph = pg.BarGraphItem(x=x, height=y1, width=0.6, brush='g')

In order to do this we use setOpacity method with the bar graph object

Syntax : bargraph.setOpacity(n)

Argument : It takes float value as argument

Return : It returns None

下面是实现

# importing QtGui to use QIcon
from PyQt5.QtGui import * from PyQt5.QtCore import Qt 
  
# importing pyqtgraph as pg
import pyqtgraph as pg
  
# importing QtCore and QtGui from the pyqtgraph module
from pyqtgraph.Qt import QtCore, QtGui
  
# importing numpy as np
import numpy as np
  
import time
  
# creating a pyqtgraph plot window
window = pg.plot()
  
# icon for plot window
icon = QIcon("logo.png")
  
# setting icon to the plot window
window.setWindowIcon(icon)
  
# setting window geometry
# left = 100, top = 100
# width = 600, height = 500
window.setGeometry(100, 100, 600, 500)
  
# title for the plot window
title = "GeeksforGeeks PyQtGraph"
  
# setting window title to plot window
window.setWindowTitle(title)
  
# create list for y-axis
y1 = [5, 5, 7, 10, 3, 8, 9, 1, 6, 2]
  
# create horizontal list i.e x-axis
x = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
  
# create pyqt5graph bar graph item 
# with width = 0.6
# with bar colors = green
bargraph = pg.BarGraphItem(x = x, height = y1, width = 0.6, brush ='g')
  
# add item to plot window
# adding bargraph item to the window
window.addItem(bargraph)
  
# setting opacity level of the bargraph
bargraph.setOpacity(0.3)
    
  
  
# main method
if __name__ == '__main__':
      
    # importing system
    import sys
      
    # Start Qt event loop unless running in interactive mode or using 
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()
         

输出 ：