Overlay Image on Matplotlib Plot

Introduction

This tutorial will show you how to overlay an image on a Matplotlib plot by moving it to the front and making it semi-transparent. The tutorial uses the figimage method from the matplotlib.figure.Figure class and the imread method from the matplotlib.image module.

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Import Required Libraries

First, we need to import the required libraries, including matplotlib.pyplot, numpy, matplotlib.cbook, and matplotlib.image.

import matplotlib.pyplot as plt
import numpy as np
import matplotlib.cbook as cbook
import matplotlib.image as image

Load Image

Next, we need to load the image that we want to overlay on the plot. We can use the get_sample_data method from the matplotlib.cbook module to load a sample image. In this example, we will use the logo2.png image.

with cbook.get_sample_data('logo2.png') as file:
    im = image.imread(file)

Create Plot

Now, we can create the plot that we want to overlay the image on. In this example, we will create a simple bar plot using random data.

fig, ax = plt.subplots()

np.random.seed(19680801)
x = np.arange(30)
y = x + np.random.randn(30)
ax.bar(x, y, color='#6bbc6b')
ax.grid()

Overlay Image

To overlay the image on the plot, we can use the figimage method from the matplotlib.figure.Figure class. We need to specify the image, the position of the image on the plot, the z-order (to move the image to the front), and the alpha (to make the image semi-transparent).

fig.figimage(im, 25, 25, zorder=3, alpha=.7)

Display Plot

Finally, we can display the plot using the show method from the matplotlib.pyplot module.

plt.show()

Summary

This tutorial showed you how to overlay an image on a Matplotlib plot using the figimage method and the imread method. By following the above steps, you can create beautiful visualizations with custom images on top.