In this article we will see how we can get the opacity of the spots in scatter plot graph in the PyQtGraph module. 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.). A scatter plot (aka scatter chart, scatter graph) uses dots to represent values for two different numeric variables. It is a type of plot or mathematical diagram using Cartesian coordinates to display values for typically two variables for a set of data. The position of each dot on the horizontal and vertical axis indicates values for an individual data point. Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light. In radiative transfer, it describes the absorption and scattering of radiation in a medium, such as a plasma, dielectric, shielding material, glass, etc. It can be set with the help of setOpacity method.
We can create a plot window and create scatter plot graph on it with the help of commands given below
# creating a pyqtgraph plot window plt = pg.plot() # creating a scatter plot graph of size = 10 scatter = pg.ScatterPlotItem(size=10)
In order to do this we use opacity method with the scatter plot graph object
Syntax : scatter.opacity()
Argument : It takes no argument
Return : It returns float value
Below is the implementation
Python3
# importing Qt widgetsfrom PyQt5.QtWidgets import *# importing systemimport sys# importing numpy as npimport numpy as np# importing pyqtgraph as pgimport pyqtgraph as pgfrom PyQt5.QtGui import *from PyQt5.QtCore import *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("Geeksforneveropen Scatter Plot") # making label do word wrap label.setWordWrap(True) # creating a plot window plot = pg.plot() # number of points n = 300 # creating a scatter plot item # of size = 10 # using brush to enlarge the of green color scatter = pg.ScatterPlotItem(size=10, brush=pg.mkBrush(30, 255, 35, 255)) # data for x-axis x_data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] # data for y-axis y_data = [5, 4, 6, 4, 3, 5, 6, 6, 7, 8] # setting data to the scatter plot scatter.setData(x_data, y_data) # add item to plot window # adding scatter plot item to the plot window plot.addItem(scatter) # 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(plot, 0, 1, 3, 1) # setting this widget as central widget of the main window self.setCentralWidget(widget) # setting opacity of scatter plot spots scatter.setOpacity(0.2) # getting opacity of the scatter plot value = scatter.opacity() # setting text to the value label.setText("Opacity level : " + str(value))# create pyqt5 appApp = QApplication(sys.argv)# create the instance of our Windowwindow = Window()# start the appsys.exit(App.exec()) |
Output :
