D3.js time.interpolate() Function

Last Updated : 23 Aug, 2020

The time.interpolate() function in D3.js is used to change the scale’s range interpolator factory. It returns the current interpolator if the factory is not specified.

Syntax:

time.interpolate( interpolate )

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

interpolate: This parameter takes the interpolator function.

Below programs illustrate the time.interpolate() function in D3.js:

Example 1:

HTML

<!DOCTYPE html> 
<html> 
  
<head> 
    <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> 
</head> 
  
<body> 
    <h1 style="color: green"> 
        GeeksforGeeks 
    </h1> 
  
    <p>time.interpolate() Function </p> 
  
    <script> 
        var time = d3.scaleTime() 
  
            // Setting domain and range 
            // for the scale 
            .domain([1, 10]) 
            .range([1, 100]) 
  
            // Using the specified interpolation 
            .interpolate(d3.interpolateRound); 
  
        document.write("<h3>time(0.5): " + 
            time(0.5) + "</h3>"); 
        document.write("<h3>time(21): " + 
            time(21) + "</h3>"); 
        document.write("<h3>time(5.5): " + 
            time(5.5) + "</h3>"); 
        document.write("<h3>time(1.5): " + 
            time(1.5) + "</h3>"); 
    </script> 
</body> 
  
</html> 

Output:

Example 2:

HTML

<!DOCTYPE html> 
<html> 
  
<head> 
    <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> 
  
    <style> 
        div { 
            width: 200px; 
            height: 40px; 
            text-align: center; 
            background-color: rgb(100, 150, 200); 
        } 
    </style> 
</head> 
  
<body> 
    <h1 style="color: green"> 
        GeeksforGeeks 
    </h1> 
  
    <p>time.interpolate() Function </p> 
  
    <div class="b1">time(4.5)</div> 
    <div class="b2">time(40)</div> 
    <div class="b3">time(11.5)</div> 
    <div class="b4">time(99.5)</div> 
    <script> 
        var time = d3.scaleTime() 
  
            // Setting domain and range 
            // for the scale 
            .domain([0, 100]) 
            .range(["blue", "yellow", "green"]) 
  
            // Using the specified interpolation 
            .interpolate( 
                d3.interpolateCubehelix.gamma(0.5) 
            ); 
  
        var color1 = time(4.5); 
        var color2 = time(40); 
        var color3 = time(11.5); 
        var color4 = time(99.5); 
        var div1 = document.querySelector(".b1") 
            .style.backgroundColor = color1; 
        var div2 = document.querySelector(".b2") 
            .style.backgroundColor = color2; 
        var div3 = document.querySelector(".b3") 
            .style.backgroundColor = color3; 
        var div4 = document.querySelector(".b4") 
            .style.backgroundColor = color4; 
    </script> 
</body> 
  
</html> 