In this article, we will see how we can show the video in PyQTGraph. PyQtGraph is a graphics and user interface library for Python that provides functionality commonly required in designing and science applications. Its primary goals are to provide fast, interactive graphics for displaying data (plots, video, etc.). Widget used for display and analysis of image data. Implements many features like displaying 2D and 3D image data. For 3D data, a z-axis slider is displayed allowing the user to select which frame is displayed. Displays histogram of image data with a movable region defining the dark/light levels, editable gradient provides a color lookup table. Video is displayed using the image view object and updating the frame very time.
We can create an image view with the help of the command given below
# 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
In order to plot the video we have to do the following
- Import the pyqtgraph, pyqt5 and numpy module
- Create a main window class
- Create a graphic layout widget and add image view box to it
- Create an image item object and add it to the image view
- Create random data for the image item
- Create an update data method which updates the data of the image constantly to make it appear like a video and call this method
- Add graphic layout to the grid layout of main window and set this widget as central widget
Below is the implementation
# 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 window
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 ())
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Output :