Less.js Color Operation fadein() Function

Last Updated : 06 Oct, 2022

Less.js is a simple CSS pre-processor that facilitates the creation of manageable, customizable, and reusable style sheets for websites. It is better since CSS makes use of a dynamic style sheet language. LESS is flexible enough to work in a wide range of browsers. To create and improve CSS so that web browsers can use it, a computer language known as the CSS pre-processor is used. In addition, it is a CSS language extension that provides tools like variables, functions, mixins, and operations to help with the development of dynamic CSS while preserving backward compatibility.

In this article, we are going to discuss the Color Operation fadein() function in Less.JS, along with knowing their basic implementation through the illustration.

The fadein() function is to regulate the exact opacity of a color object. Opacity can be set or reset. So this function takes hex value, RGB value, HSL or HSV value and it returns a value with that required opacity.

Syntax:

fadein(color, amount)

Parameter values:

color: This is the first parameter and it is compulsory, it can be a hex value, RGB value, HSL, or HSV value.
amount: This parameter is also compulsory and it signifies the amount of opacity that is needed to be applied. This parameter takes a value from 0-100% range.

Please refer to the How to pre-compile LESS into CSS article for a detailed description.

Example 1: The below code example demonstrates the usage and implementation of the Color Operation fadein() function in Less.js.

HTML

<!DOCTYPE html> 
<html> 
  
<head> 
    <link rel="stylesheet" 
        type="text/css" href="style.css" /> 
</head> 
  
<body> 
    <h1 style="color:green;"> 
        GeeksforGeeks 
    </h1> 
      
    <h3>Less.js Color Operation fadein() Function</h3> 
      
    <div class="c1"> 
        <p> 
            fadein(hsl(90, 100%, 50%), 35%)<br> 
            (HSLA Value)<br>hsl(90, 100%, 50%) 
        </p> 
    </div> 
</body> 
  
</html>

styles.less

@body-bg-color: #eeeeee; 
  
body{ 
    background-color: @body-bg-color; 
} 
.c1 {   
    width: 250px;   
    height: 150px;   
    margin: 1rem; 
    background-color: fadein(hsl(90, 100%, 50%), 35%);   
}   
p{   
    padding: 40px 0px 0px 20px;   
}

Syntax: To compile the above LESS code to CSS code, run the following command:

lessc styles.less styles.css

style.css: The CSS output of the above Less file was compiled

style.css

body { 
    background-color: #eeeeee; 
} 
  
.c1 { 
    width: 250px; 
    height: 150px; 
    margin: 1rem; 
    background-color: hsl(90, 100%, 50%); 
} 
  
p { 
    padding: 40px 0px 0px 20px; 
}

Output:

Example 2: The below code example demonstrates the usage and implementation of the Color Operation fadein() function with the if() and boolean logical functions and the color type function.

HTML

<!DOCTYPE html> 
<html> 
  
<head> 
    <link rel="stylesheet" 
        type="text/css" href="style.css" /> 
</head> 
  
<body> 
    <h1 style="color:green;"> 
        GeeksforGeeks 
    </h1> 
      
    <h3>Less.js Color Operation fadein() Function</h3> 
      
    <div class="c1"> 
        <p> 
            fadein(hsla(90, 100%, 50%, 0.2), 65%)<br> 
            (HSLA Value)<br>hsla(90, 100%, 50%, 0.85) 
        </p> 
    </div> 
</body> 
  
</html>

style.less

/* styles.less */
@body-bg-color: #eeeeee; 
@color: hsl(150, 100%, 39%); 
@second: rgb(58, 21, 11); 
@hex: fadein(hsla(90, 100%, 50%, 0.2), 65%); 
@cond1: boolean(iscolor(@hex)); 
  
body { 
    background-color: @body-bg-color; 
} 
  
.c1 { 
    width: 250px; 
    height: 150px; 
    margin: 1rem; 
    background-color: if(@cond1, @second, @color); 
} 
  
p { 
    padding: 50px 0px 0px 45px; 
    color: @hex; 
}

Syntax: To compile the above LESS code to CSS code, run the following command.

lessc styles.less styles.css

style.css: The CSS output of the above Less file was compiled.

style.css

/* styles.less */
body { 
    background-color: #eeeeee; 
} 
  
.c1 { 
    width: 250px; 
    height: 150px; 
    margin: 1rem; 
    background-color: #3a150b; 
} 
  
p { 
    padding: 50px 0px 0px 45px; 
    color: hsla(90, 100%, 50%, 0.85); 
}