PyQtGraph is a graphics and user interface Python library for functionalities commonly required in designing and science applications. Its provides fast, interactive graphics for displaying data (plots, video, etc.). A line chart is a type of graph which displays information as a series of data points commonly known as markers, connected by straight line segments. A scatter plot uses dots to represent values for two different numeric variables. It is a type of graph, drawn using Cartesian coordinates to display values for typically two variables for a set of data
When we create a line graph or scatter plot graph, the points which represent some data needs to be highlighted using certain symbols, by default it is round circle but this can be modified as required. There are a total of 12 symbols which are offered by pyqtgraph which can be used to change symbol as required.
Below are the list of the symbols available in this module:
- o : Default symbol, round circle symbol
- t : Triangle pointing downwards symbol
- t1 : Triangle pointing upwards symbol
- t2 : Triangle pointing right side symbol
- t3 : Triangle pointing left side symbol
- s : Square symbol
- p : Pentagon symbol
- h : Hexagon symbol
- star : Star symbol
- + : Plus symbol
- d : Prism symbol
- x : Cross symbol
This is how they appear on the output screen:
We can create a plot window with the help of commands given below :
plt = pg.plot()
In order to implement the above explained concept, following steps can be followed:
- Import pyqtgraph, pyqt5 and numpy modules
- Create Main window class
- Create a plot window object
- Add legend to the plot window
- Create 12 lines having different points so that they don’t intersect each other and hiving different symbol and colors
- Add the plot window and other widget like label to the grid layout
- Set grid layout widget as the central widget of the main window
Example:
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 * from collections import namedtupleclass Window(QMainWindow): def __init__(self): super().__init__() # setting title self.setWindowTitle("PyQtGraph") # setting geometry self.setGeometry(100, 100, 800, 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() # text text = "GeeksforLazyroar Different Symbols" # creating a label label = QLabel(text) # setting minimum width label.setMinimumWidth(130) # making label do word wrap label.setWordWrap(True) # setting pyqtgraph configuration pg.setConfigOptions(antialias = True) # creating a plot window plot = pg.plot() # adding legend to the plot window plot.addLegend() # plot the line1 with symbol o # having color blue line1 = plot.plot([1, 1, 1, 1, 1], pen =(0, 0, 200), symbolBrush =(0, 0, 200), symbolPen ='w', symbol ='o', symbolSize = 14, name ="symbol ='o'") # plot the line2 with symbol t # having color green line2 = plot.plot([2, 2, 2, 2, 2], pen =(0, 128, 0), symbolBrush =(0, 128, 0), symbolPen ='w', symbol ='t', symbolSize = 14, name ="symbol ='t'") # plot the line3 with symbol t1 # having color bluegreen line3 = plot.plot([3, 3, 3, 3, 3], pen =(19, 234, 201), symbolBrush =(19, 234, 201), symbolPen ='w', symbol ='t1', symbolSize = 14, name ="symbol ='t1'") # plot the line4 with symbol t2 # having color purple line4 = plot.plot([4, 4, 4, 4, 4], pen =(195, 46, 212), symbolBrush =(195, 46, 212), symbolPen ='w', symbol ='t2', symbolSize = 14, name ="symbol ='t2'") # plot the line5 with symbol t3 # having color brownish line5 = plot.plot([5, 5, 5, 5, 5], pen =(250, 194, 5), symbolBrush =(250, 194, 5), symbolPen ='w', symbol ='t3', symbolSize = 14, name ="symbol ='t3'") # plot the line6 with symbol s # having color grey line6 = plot.plot([6, 6, 6, 6, 6], pen =(54, 55, 55), symbolBrush =(55, 55, 55), symbolPen ='w', symbol ='s', symbolSize = 14, name ="symbol ='s'") # plot the line7 with symbol p # having color sky blue line7 = plot.plot([7, 7, 7, 7, 7], pen =(0, 114, 189), symbolBrush =(0, 114, 189), symbolPen ='w', symbol ='p', symbolSize = 14, name ="symbol ='p'") # plot the line8 with symbol h # having color orange line8 = plot.plot([8, 8, 8, 8, 8], pen =(217, 83, 25), symbolBrush =(217, 83, 25), symbolPen ='w', symbol ='h', symbolSize = 14, name ="symbol ='h'") # plot the line9 with symbol star # having yellow color line9 = plot.plot([9, 9, 9, 9, 9], pen =(237, 177, 32), symbolBrush =(237, 177, 32), symbolPen ='w', symbol ='star', symbolSize = 14, name ="symbol ='star'") # plot the line10 with symbol + # having bluish color line10 = plot.plot([10, 10, 10, 10, 10], pen =(126, 47, 142), symbolBrush =(126, 47, 142), symbolPen ='w', symbol ='+', symbolSize = 14, name ="symbol ='+'") # plot the line11 with symbol d # having greenish color line11 = plot.plot([11, 11, 11, 11, 11], pen =(119, 172, 48), symbolBrush =(119, 172, 48), symbolPen ='w', symbol ='d', symbolSize = 14, name ="symbol ='d'") # plot the line12 with symbol x # having off white color line12 = plot.plot([12, 12, 12, 12, 12], pen =(180, 180, 180), symbolBrush =(180, 180, 180), symbolPen ='w', symbol ='x', symbolSize = 14, name ="symbol ='x'") # setting x-axis range plot.setXRange(-3, 4) # 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)# create pyqt5 appApp = QApplication(sys.argv)# create the instance of our Windowwindow = Window()# start the appsys.exit(App.exec()) |
Output :
