Interactive Plotting with Textbox

Introduction

In this tutorial, we will learn how to create an interactive plot with a textbox using Matplotlib. The Textbox widget allows users to provide text input, which updates the plot in real-time.

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Import Required Libraries

First, we need to import the necessary libraries. We will be using NumPy and Matplotlib to create the plot and the Textbox widget.

import matplotlib.pyplot as plt
import numpy as np
from matplotlib.widgets import TextBox

Create the Initial Plot

Next, we create the initial plot that will be updated based on the user's input. In this example, we create a plot of a function with t as the independent variable.

fig, ax = plt.subplots()
fig.subplots_adjust(bottom=0.2)

t = np.arange(-2.0, 2.0, 0.001)
l, = ax.plot(t, np.zeros_like(t), lw=2)

Define the Submit Function

We define the submit function that will be called when the user submits the text input. This function updates the plotted function based on the user's input.

def submit(expression):
    """
    Update the plotted function to the new math *expression*.

    *expression* is a string using "t" as its independent variable, e.g.
    "t ** 3".
    """
    ydata = eval(expression, {'np': np}, {'t': t})
    l.set_ydata(ydata)
    ax.relim()
    ax.autoscale_view()
    plt.draw()

Create the Textbox Widget

We create the Textbox widget and add it to the figure. The on_submit method is used to trigger the submit function when the user presses enter in the textbox or leaves the textbox. We also set the initial value of the Textbox widget to t ** 2.

axbox = fig.add_axes([0.1, 0.05, 0.8, 0.075])
text_box = TextBox(axbox, "Evaluate", textalignment="center")
text_box.on_submit(submit)
text_box.set_val("t ** 2")  ## Trigger `submit` with the initial string.

Display the Plot

Finally, we display the plot to the user.

plt.show()

Summary

In this tutorial, we learned how to create an interactive plot with a textbox using Matplotlib. We created an initial plot, defined a submit function that updates the plot, created a Textbox widget, and displayed the plot to the user. With this knowledge, you can create your own interactive plots with user input.