Prerequisites: Matplotlib
Given an image the task here is to draft a python program using matplotlib to draw a rectangle on it. Matplotlib comes handy with rectangle() function which can be used for our requirement.
Syntax: Rectangle(xy, width, height, angle=0.0, **kwargs)
Parameters:
- xy: Lower left point to start the rectangle plotting
- width : width of the rectangle
- height: Height of the rectangle.
- angle: Angle of rotation of the rectangle.
Approach
- Import the necessary libraries.
- Insert and display the image.
- Create the figure and axes of the plot
- Add the patch to the Axes
- Display the image
Example 1: Draw a rectangle on an image
Python3
import matplotlib.pyplot as plt import matplotlib.patches as patches from PIL import Image import numpy as np x = np.array(Image.open('geek.png'), dtype=np.uint8) plt.imshow(x) # Create figure and axes fig, ax = plt.subplots(1) # Display the image ax.imshow(x) # Create a Rectangle patch rect = patches.Rectangle((50, 100), 40, 30, linewidth=1, edgecolor='r', facecolor="none") # Add the patch to the Axes ax.add_patch(rect) plt.show() |
Output:
original image
image with rectangle
Example 2: Draw a filled rectangle
Python3
import matplotlib.pyplot as plt import matplotlib.patches as patches from PIL import Image import numpy as np x = np.array(Image.open('geek.png'), dtype=np.uint8) plt.imshow(x) # Create figure and axes fig, ax = plt.subplots(1) # Display the image ax.imshow(x) # Create a Rectangle patch rect = patches.Rectangle((50, 100), 40, 30, linewidth=1, edgecolor='r', facecolor="g") # Add the patch to the Axes ax.add_patch(rect) plt.show() |
Output:
original image
image with rectangle
