Python Pillow - ImageChops.constant() Function

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The PIL.ImageChops.constant function is used to fill a channel of an image with a given grey level. This grey level value should be within the valid range for pixel values (e.g., 0 to 255 for an 8-bit image).

Syntax

Following is the syntax of the function −

PIL.ImageChops.constant(image, value)

Parameters

Here's a brief explanation of the parameters −

• image − The input image.

• value − Integer value that represents the grey level value to fill the channel.

Return Value

The return type of this function is an Image.

Examples

Example 1

Here's an example that demonstrates the pixel values before and after using ImageChops.constant() function.

from PIL import Image, ImageChops
import numpy as np

# Create a simple RGB image with some variation in pixel values
original_image = Image.fromarray(np.array([(35, 64, 3), (255, 0, 0), (255, 255, 0), (255, 255, 255), (164, 0, 3)]), mode="RGB")

print("Original Pixel values at (0, 0):", original_image.getpixel((0, 0)))

# Fill the red channel with a constant grey level value of 128
result = ImageChops.constant(original_image, value=100)

print("Pixel values of the result at (0, 0) after constant:", result.getpixel((0, 0)))

Output

Original Pixel values at (0, 0): (35, 0, 0)
Pixel values of the result at (0, 0) after constant: 100

Example 2

In this example, the ImageChops.constant() function is used to fill the original image of PNG type with a constant grey level value of 128.

from PIL import Image, ImageChops

# Open an image file
original_image = Image.open('Images/pillow-logo-w.png')

# Fill the red channel with a constant grey level value of 128
result = ImageChops.constant(original_image, value=128)

# Display the input and resulting images
original_image.show()
result.show()

Output

Input Image

Output Image

Example 3

The following example demonstrates how to modify the image pixel values by filling it with a constant grey level value of 100.

from PIL import Image, ImageChops

# Open an image file
original_image = Image.open('Images/butterfly.jpg')
print("Original Pixel values at (0, 0):", original_image.getpixel((0, 0)))

# Fill the red channel with a constant grey level value of 128
result = ImageChops.constant(original_image, value=100)
print("Pixel values of the result at (0, 0) after constant:", result.getpixel((0, 0)))

# Display the input and resulting images
original_image.show()
result.show()

Output

Input Image 1

Output Image