PyQtGraph - 显示视频

在本文中，我们将看到如何在 PyQTGaph 中显示视频。 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。用于显示和分析图像数据的小部件。实现许多功能，例如显示 2D 和 3D 图像数据。对于 3D 数据，会显示一个 z 轴滑块，允许用户选择要显示的帧。显示具有定义暗/亮级别的可移动区域的图像数据直方图，可编辑渐变提供颜色查找表。使用图像视图对象显示视频并非常及时地更新帧。
我们可以在下面给出的命令的帮助下创建一个图像视图

# creating a pyqtgraph image view object
imv = pg.ImageView()

Syntax: ImageView(parent=None, name=’ImageView’, view=None, imageItem=None, levelMode=’mono’, *args)

Parameters:

• parent (QWidget): Specifies the parent widget to which this ImageView will belong. If None, then the ImageView is created with no parent.
• name (str): The name used to register both the internal ViewBox and the PlotItem used to display ROI data.
• view (ViewBox or PlotItem): If specified, this will be used as the display area that contains the displayed image.
• imageItem (ImageItem): If specified, this object will be used to display the image. Must be an instance of ImageItem or other compatible object.
• levelMode: specifies the *levelMode* argument

Returns: Object of class ImageView

为了绘制视频，我们必须执行以下操作

1. 导入 pyqtgrah、pyqt5 和 numpy 模块
2. 创建一个主窗口类
3. 创建一个图形布局小部件并向其添加图像视图框
4. 创建一个图像项对象并将其添加到图像视图中
5. 为图像项创建随机数据
6. 创建一个更新数据方法，不断更新图像的数据，使其看起来像视频并调用该方法
7. 将图形布局添加到主窗口的网格布局并将此小部件设置为中央小部件
   

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 Video")
  
        # setting minimum width
        label.setMinimumWidth(130)
  
        # making label do word wrap
        label.setWordWrap(True)
  
        # setting configuration options
        pg.setConfigOptions(antialias = True)
  
        # creating a graphics layout widget
        win = pg.GraphicsLayoutWidget()
  
        # adding view box object to graphic window
        view = win.addViewBox()
  
        ##lock the aspect ratio so pixels are always square
        view.setAspectLocked(True)
  
        # Create image item
        self.img = pg.ImageItem(border='w')
  
        # adding image item to the view box
        view.addItem(self.img)
  
        # Set initial view bounds
        view.setRange(QRectF(0, 0, 600, 600))
  
        #  Create random image
        self.data = np.random.normal(size=(15, 600, 600), 
                                     loc = 1024, scale = 64).astype(np.uint16)
  
        # helps in incrementing
        self.i = 0
  
        # getting time
        self.updateTime = ptime.time()
  
        # fps
        self.fps = 0
  
        # method to update the data of image
        def updateData():
  
            ## Display the data
            self.img.setImage(self.data[self.i])
  
            # creating new value of i
            self.i = (self.i + 1) % self.data.shape[0]
  
            # creating a qtimer
            QTimer.singleShot(1, updateData)
  
            # getting current time
            now = ptime.time()
  
            # temporary fps
            fps2 = 1.0 / (now - self.updateTime)
  
            # updating the time
            self.updateTime = now
  
            # setting original fps value
            self.fps = self.fps * 0.9 + fps2 * 0.1
  
        # call the update method
        updateData()
  
        # 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 ：