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:
# 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 * from collections import namedtuple
class 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 = "Geeksforgeeks 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 app App = QApplication(sys.argv)
# create the instance of our Window window = Window()
# start the app sys.exit(App. exec ())
|
Output :