D3.js interpolateReds() function

Last Updated : 18 Aug, 2020

The d3.interpolateReds() function in D3.js is used to return a range of color in red. In simple words, it returns different shades of red color depending on the integer value given as the parameter.

Syntax:

d3.interpolateReds(t);

Parameters: This function accepts a single parameter as mentioned above and described below:

t: It is any number in the range 0 to 1.

Return Values: This function returns an RGB color string.

Below examples illustrate the D3.js interpolateReds() function in JavaScript:

Example1:

HTML

<!DOCTYPE html> 
<html lang="en"> 
    <head> 
        <meta charset="UTF-8" /> 
        <meta
            name="viewport"
            content="width=device-width,  
                     initial-scale=1.0"/> 
        <title>D3.js interpolateReds() function</title> 
    </head> 
    <style></style> 
    <body> 
        <!--Fetching from CDN of D3.js -->
        <script src= 
"https://d3js.org/d3.v4.min.js"> 
        </script> 
        <script src= 
"https://d3js.org/d3-color.v1.min.js"> 
        </script> 
        <script src= 
"https://d3js.org/d3-interpolate.v1.min.js"> 
        </script> 
        <script src= 
"https://d3js.org/d3-scale-chromatic.v1.min.js"> 
        </script> 
        <script> 
            console.log(d3.interpolateReds(0)); 
            console.log(d3.interpolateReds(0.124)); 
            console.log(d3.interpolateReds(0.52)); 
            console.log(d3.interpolateReds(0.42)); 
            console.log(d3.interpolateReds(0.24)); 
            console.log(d3.interpolateReds(0.8)); 
            console.log(d3.interpolateReds(0.12)); 
            console.log(d3.interpolateReds(1)); 
        </script> 
    </body> 
</html>

Output:

Example 2:

HTML

<!DOCTYPE html> 
<html lang="en"> 
    <head> 
        <meta charset="UTF-8" /> 
        <meta
            name="viewport"
            content="width=device-width,  
                     initial-scale=1.0"/> 
        <title>D3.js interpolateReds() function</title> 
    </head> 
    <style> 
        div { 
            padding: 5px; 
            text-align: center; 
            vertical-align: middle; 
            display: flex; 
            justify-content: center; 
            width: fit-content; 
            height: 50px; 
            float: left; 
        } 
    </style> 
    <body> 
        <h2>D3.interpolateReds()</h2> 
        <div class="box1"> 
            <span> 
                (0.1) 
            </span> 
        </div> 
        <div class="box2"> 
            <span> 
                (0.2) 
            </span> 
        </div> 
        <div class="box3"> 
            <span> 
                (0.3) 
            </span> 
        </div> 
        <div class="box4"> 
            <span> 
                (0.4) 
            </span> 
        </div> 
        <div class="box5"> 
            <span> 
                (0.5) 
            </span> 
        </div> 
        <div class="b6"> 
            <span> 
                (0.6) 
            </span> 
        </div> 
        <div class="b7"> 
            <span> 
                (0.7) 
            </span> 
        </div> 
        <div class="b8"> 
            <span> 
                (0.8) 
            </span> 
        </div> 
        <div class="b9"> 
            <span> 
                (0.9) 
            </span> 
        </div> 
        <div class="b10"> 
            <span style="color: honeydew;"> 
                (1.0) 
            </span> 
        </div> 
        <!--Fetching from CDN of D3.js -->
        <script src= 
"https://d3js.org/d3.v4.min.js"> 
        </script> 
        <script src= 
"https://d3js.org/d3-color.v1.min.js"> 
        </script> 
        <script src= 
"https://d3js.org/d3-interpolate.v1.min.js"> 
        </script> 
        <script src= 
"https://d3js.org/d3-scale-chromatic.v1.min.js"> 
        </script> 
        <script> 
            // Creating different colors for different 
            // Values of t as 0.1,0.2... 1.0 
            let color1 = d3.interpolateReds(0.1); 
            let color2 = d3.interpolateReds(0.2); 
            let color3 = d3.interpolateReds(0.3); 
            let color4 = d3.interpolateReds(0.4); 
            let color5 = d3.interpolateReds(0.5); 
            let color6 = d3.interpolateReds(0.6); 
            let color7 = d3.interpolateReds(0.7); 
            let color8 = d3.interpolateReds(0.8); 
            let color9 = d3.interpolateReds(0.9); 
            let color10 = d3.interpolateReds(1.0); 
  
            // Selecting Div using query selector 
            let box1 = document.querySelector(".box1"); 
            let box2 = document.querySelector(".box2"); 
            let box3 = document.querySelector(".box3"); 
            let box4 = document.querySelector(".box4"); 
            let box5 = document.querySelector(".box5"); 
            let b6 = document.querySelector(".b6"); 
            let b7 = document.querySelector(".b7"); 
            let b8 = document.querySelector(".b8"); 
            let b9 = document.querySelector(".b9"); 
            let b10 = document.querySelector(".b10"); 
  
            // Setting style and BG color of the particular DIVs 
            box1.style.backgroundColor = color1; 
            box2.style.backgroundColor = color2; 
            box3.style.backgroundColor = color3; 
            box4.style.backgroundColor = color4; 
            box5.style.backgroundColor = color5; 
            b6.style.backgroundColor = color6; 
            b7.style.backgroundColor = color7; 
            b8.style.backgroundColor = color8; 
            b9.style.backgroundColor = color9; 
            b10.style.backgroundColor = color10; 
        </script> 
    </body> 
</html> 