CSS | invert() Function

Last Updated : 03 Jun, 2020

The invert() function is an inbuilt function that is used to apply a filter to the image to set the invert of the color of the sample image.

Syntax:

invert( amount )

Parameters: This function accepts single parameter amount which holds the amount of conversion. The value of invert is set in terms of value and percentage. The value 0% represents original image and 100% represents the inverted image.

The invert() function internally uses the following formula, to computer the inverse of the image:

amount * (255 - value) + (1 - amount) * value

The value of inversion is controlled by the variable amount, the variable value lies between 0 – 1(floating) range (this is done by converting the passed percentage of color inversion to a value between 0-1). The value is the the color value of the pixel. (255-value) gives the color after subtracting the color value with the max pixel value, assumes that the value of the pixel is in the range 0 – 255 (though input image sample space could be stretched/scaled to meet the specified criteria).

Below is a table containing a list of inversion percentages and the result they produce.

Inversion	Result
0%	Original Image
50%	Image with each pixel having grey color
100%	Completely inverted Image

Below example illustrates CSS invert() function in CSS:
Example:

<!DOCTYPE html> 
<html> 
  
<head> 
    <title>CSS invert() Function</title> 
      
    <style>
        h1 {
            color:green;
        }
        body {
            text-align:center;
        }
        .invert_effect {
            filter: invert(100%);
        }
    </style>
</head> 
  
<body> 
    <h1>GeeksforGeeks</h1> 
      
    <h2>CSS invert() function</h2>
      
    <img class="invert_effect" src= 
"https://media.geeksforgeeks.org/wp-content/cdn-uploads/20190710102234/download3.png"
        alt="GeeksforGeeks logo"> 
</body> 
  
</html>