In this article we will see how we can create a mouse press event with the bar 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.) and second is to provide tools to aid in rapid application development (for example, property trees such as used in Qt Designer).A bar chart or bar graph is a chart or graph that presents categorical data with rectangular bars with heights or lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally. A vertical bar chart is sometimes called a column chart. This event get triggered when the mouse button is pressed on the bar graph. There is a difference between mouse press and release event although they occur due to the mouse button but at different time.
We can create a plot window and bar graph with the help of commands given below
# creating a pyqtgraph plot window window = pg.plot() # creating a bar graph of green color bargraph = pg.BarGraphItem(x=x, height=y1, width=0.6, brush='g')
In order to do this we have modify the bar graph class, below is the class which can be used
# Bar Graph class
class BarGraphItem(pg.BarGraphItem):
# constructor which inherit original
# BarGraphItem
def __init__(self, *args, **kwargs):
pg.BarGraphItem.__init__(self, *args, **kwargs)
# creating mouse press event
def mousePressEvent(self, event):
# rotating the bargraph
r = self.rotation()
self.setRotation(r+10)
# print the message
print("Mouse Press Event")
Below is the implementation
Python3
# importing Qt widgetsfrom PyQt5.QtWidgets import * import sys# importing pyqtgraph as pgimport pyqtgraph as pgfrom PyQt5.QtGui import *# Bar Graph classclass BarGraphItem(pg.BarGraphItem): # constructor which inherit original # BarGraphItem def __init__(self, *args, **kwargs): pg.BarGraphItem.__init__(self, *args, **kwargs) # creating parent changed event def mousePressEvent(self, event): # rotating the bargraph r = self.rotation() self.setRotation(r + 10) # print the message print("Mouse Press Event")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 plot window plot = pg.plot() # create list for y-axis y1 = [5, 5, 7, 10, 3, 8, 9, 1, 6, 2] # create horizontal list i.e x-axis x = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] # create pyqt5graph bar graph item # with width = 0.6 # with bar colors = green bargraph = BarGraphItem(x = x, height = y1, width = 0.6, brush ='g') # bargraph.viewRangeChanged.connect(lambda: print("sss")) # add item to plot window # adding bargraph item to the plot window plot.addItem(bargraph) # Creating a grid layout layout = QGridLayout() # setting this layout to the widget widget.setLayout(layout) # 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 :
Mouse Press Event Mouse Press Event Mouse Press Event Mouse Press Event Mouse Press Event Mouse Press Event Mouse Press Event
