In this article we will see how we can create a view range changed 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 view ranged of the bar graph is changed. When we move the graph above the view range this event get triggered
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 view range changed event def viewRangeChanged(self): # print the message print("View Range Event")
Below is the implementation
View Range Event View Range Event View Range Event View Range Event
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