Interactivity takes many forms. Widgets are visible elements that are primarily interacted with via the mouse. In this chapter, we covered all of Matplotlib's GUI-neutral widgets. Widgets such as sliders, checkboxes, and radio buttons were all integrated into our application's event framework. Doing so allowed for multiple ways to update the state of the application and for the state of the widgets to be updated as well. Widgets such as Lasso and Button were added as input mechanisms, providing the means to modify the data that the application displays. Other widgets were also covered but not included into our main application such as RectangleSelector and SpanSelector. A few ways of using these widgets were demonstrated, from selecting data to measuring distances. We even went over how to create a specialized Axes subclass that operates seamlessly with the rest of Matplotlib for the purpose of extending the data display of the figure window.

Finally, we went over a variety of third...