PyQtGraph - 创建图形项

在本文中，我们将看到如何在 PyQTGaph 中创建图形项。 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。图是由节点和边组成的非线性数据结构。节点有时也称为顶点，边是连接图中任意两个节点的线或弧。图由一组有限的顶点（或节点）和一组连接一对节点的边组成。

我们可以在下面给出的命令的帮助下创建一个图形布局小部件

# creating graphics layout widget
win = pg.GraphicsLayoutWidget()

为了绘制视频，我们必须执行以下操作

导入 pyqtgrah、pyqt5 和 numpy 模块。
创建一个主窗口类。
创建一个图形布局小部件并向其添加图像视图框。
创建一个图形项并将其添加到视图框中。
设置节点和边的位置，即连接，并为它们设置符号。
创建网格布局并将图形布局窗口与其他小部件一起添加到其中，并将网格小部件设置为主窗口的中央小部件。

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 *
import pyqtgraph.ptime as ptime
  
  
# Image View class
class ImageView(pg.ImageView):
  
    # constructor which inherit original
    # ImageView
    def __init__(self, *args, **kwargs):
        pg.ImageView.__init__(self, *args, **kwargs)
  
  
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 Graph Item")
  
        # setting minimum width
        label.setMinimumWidth(130)
  
        # making label do word wrap
        label.setWordWrap(True)
  
        # setting configuration options
        pg.setConfigOptions(antialias=True)
  
        # creating graphics layout widget
        win = pg.GraphicsLayoutWidget()
  
        # adding view box to the graphic layout widget
        view = win.addViewBox()
  
        # lock the aspect ratio
        view.setAspectLocked()
  
        # creating a graph item
        graph_item = pg.GraphItem()
  
        # adding graph item to the view box
        view.addItem(graph_item)
  
        # Define positions of nodes
        pos = np.array([
            [0, 0],
            [10, 0],
            [0, 10],
            [10, 10],
            [5, 5],
            [15, 5]
        ])
  
        # Define the set of connections in the graph
        adj = np.array([
            [0, 1],
            [1, 3],
            [3, 2],
            [2, 0],
            [1, 5],
            [3, 5],
        ])
  
        # Define the symbol to use for each node (this is optional)
        symbols = ['o', 'x', 'o', 'o', 't', '+']
  
        # Define the line style for each connection (this is optional)
        lines = np.array([
            (255, 0, 0, 255, 1),
            (255, 0, 255, 255, 2),
            (255, 0, 255, 255, 3),
            (255, 255, 0, 255, 2),
            (255, 0, 0, 255, 1),
            (255, 255, 255, 255, 4),
        ], dtype=[('red', np.ubyte), ('green', np.ubyte), ('blue', np.ubyte), ('alpha', np.ubyte), ('width', float)])
  
        # Update the graph
        graph_item.setData(pos=pos, adj=adj, pen=lines,
                           size=1, symbol=symbols, pxMode=False)
  
        # 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(win, 0, 1, 3, 1)
  
        # setting this widget as central widget of the main widow
        self.setCentralWidget(widget)
  
  
# create pyqt5 app
App = QApplication(sys.argv)
  
# create the instance of our Window
window = Window()
  
# start the app
sys.exit(App.exec())

输出：