Wand fx() function – Python

FX special effects are a powerful “micro” language to work with. Simple functions & operators offer a unique way to access & manipulate image data. The fx() method applies a FX expression, and generates a new Image instance.

We can create a custom DIY filter that will turn the image black & white, except colors with a hue above 324°, or below 36°.

Syntax :

wand.image.fx(fx_string)

Parameters :

Parameter	Input Type	Description
expression	basestring	The entire FX expression to apply.
channel	CHANNELS	Optional channel to target.

Source Image:

Example 1:

# import IMage from wand.image module
from wand.image import Image

# expression string for fx()
fx_filter ="(hue > 0.9 || hue < 0.1) ? u : lightness"

with Image(filename ="koala.jpeg") as img:
    with img.fx(fx_filter) as filtered_img:
       filtered_img.save(filename ="fx-koala.jpeg")

Output:

Example 2:

# import IMage from wand.image module
from wand.image import Image

# expression string for fx()
fx_filter ="(luma > 0.9 || luma < 0.1) ? u : lightness"

with Image(filename ="koala.jpeg") as img:
    with img.fx(fx_filter) as filtered_img:
       filtered_img.save(filename ="fx-koala.jpeg")

Output: