Drawing on images

Let's learn how to draw different figure shapes, such as a line, square, or triangle, on an image using OpenCV. When we draw any shape on an image, we need to take care of the coordinates, color, and thickness of the shape. Let's first create a blank image with a white or black background:

# Import cv2 latest version of OpenCV library
import cv2

# Import numeric python (NumPy) library
import numpy as np

# Import matplotlib for showing the image
import matplotlib.pyplot as plt

# Magic function to render the figure in a notebook
%matplotlib inline

# Let's create a black image
image_shape=(600,600,3)
black_image = np.zeros(shape=image_shape,dtype=np.int16)

# Show the image
plt.imshow(black_image)

This results in the following output:

In the preceding example, we created a blank image with a black background using the zeros() function of the NumPy module. The zeros() function creates an array of the given size and fills the matrix with zeros.

Let's create...