How to Draw Rectangle on Image in Matplotlib? (original) (raw)
Last Updated : 17 Dec, 2020
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)
fig, ax = plt.subplots( 1 )
ax.imshow(x)
rect = patches.Rectangle(( 50 , 100 ), 40 , 30 , linewidth = 1 ,
`` edgecolor = 'r' , facecolor = "none" )
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)
fig, ax = plt.subplots( 1 )
ax.imshow(x)
rect = patches.Rectangle(( 50 , 100 ), 40 , 30 , linewidth = 1 ,
`` edgecolor = 'r' , facecolor = "g" )
ax.add_patch(rect)
plt.show()
Output:
original image
image with rectangle