Create Barcode with Matplotlib

Introduction

This lab demonstrates how to create a barcode using Matplotlib in Python. The barcode is produced using a binary array of ones and zeros, and is rendered using Axes.imshow.

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Skills Graph

Import the Required Libraries

We first need to import the necessary libraries, including numpy and matplotlib.

import matplotlib.pyplot as plt
import numpy as np

Create the Binary Array

Next, we need to create the binary array that will be used to generate the barcode. In this example, we will use the following binary array:

code = np.array([
    1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1,
    0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0,
    1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1,
    1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1])

Set the Pixel and DPI Values

We need to define the pixel and DPI values for the barcode. In this example, we will use a pixel value of 4 and a DPI value of 100.

pixel_per_bar = 4
dpi = 100

Create the Figure and Axes

We need to create the figure and axes for the barcode. We will set the figure size to a multiple of the number of data points, and turn off all axis.

fig = plt.figure(figsize=(len(code) * pixel_per_bar / dpi, 2), dpi=dpi)
ax = fig.add_axes([0, 0, 1, 1])  ## span the whole figure
ax.set_axis_off()

Render the Barcode

Finally, we can render the barcode using Axes.imshow. We will use code.reshape(1, -1) to turn the data into a 2D array with one row, imshow(..., aspect='auto') to allow for non-square pixels, and imshow(..., interpolation='nearest') to prevent blurred edges.

ax.imshow(code.reshape(1, -1), cmap='binary', aspect='auto',
          interpolation='nearest')
plt.show()

Summary

In this lab, we learned how to create a barcode using Matplotlib in Python. We first imported the necessary libraries, then created a binary array that will be used to generate the barcode. We then set the pixel and DPI values and created the figure and axes. Finally, we rendered the barcode using Axes.imshow.