The black_threshold() function is an inbuilt function in the Python Wand ImageMagick library which is used to force all pixels above a given color as black and leaves all pixels above threshold unaltered.
Syntax:
black_threshold(color)Parameters: This function accepts single parameter as mentioned above and defined below:
- color: This parameter is used to specify the value of factor in order to apply black threshold. This parameter accepts values as color strings like ‘Green’, ‘Blue’, ‘Red’, ‘White’ etc.
Return Value: This function returns the Wand ImageMagick object.
Original Image:
Example 1:
Python3
# Import library from Image from wand.image import Image
# Import the image with Image(filename = '../geeksforgeeks.png' ) as image:
# Clone the image in order to process
with image.clone() as black_threshold:
# Invoke black_threshold function with threshold parameter as 'Green'
black_threshold.black_threshold( 'Green' )
# Save the image
black_threshold.save(filename = 'black_threshold1.jpg' )
|
Output:
Example 2:
Python3
# Import libraries from the wand from wand.image import Image
from wand.drawing import Drawing
from wand.color import Color
with Drawing() as draw: # Set Stroke color the circle to black
draw.stroke_color = Color( 'black' )
# Set Width of the circle to 2
draw.stroke_width = 1
# Set the fill color to 'White (# FFFFFF)'
draw.fill_color = Color( 'white' )
# Invoke Circle function with center at 50, 50 and radius 25
draw.circle(( 200 , 200 ), # Center point
( 100 , 100 )) # Perimeter point
# Set the font style
draw.font = '../Helvetica.ttf'
# Set the font size
draw.font_size = 30
with Image(width = 400 , height = 400 , background = Color( '# 45ff33' )) as pic:
# Set the text and its location
draw.text( int (pic.width / 3 ), int (pic.height / 2 ), 'GeeksForGeeks !' )
# Draw the picture
draw(pic)
# Invoke black_threshold function with threshold parameter as 'White'
pic.black_threshold( 'White' )
# Save the image
pic.save(filename = 'black_threshold2.jpg' )
|
Output: