D3.js pow.invert() Function

Last Updated : 23 Aug, 2020

The pow.invert() function is used to return a value from the domain when given a value from the range. This inversion is useful for interaction such as determining the data value that corresponds to the position of the mouse.

Syntax:

pow.invert( value )

Parameters: This function accepts only one parameter as given above and described below:

value: It is a number that belongs to any value in the given range.

Return Values: This function returns a number from the domain.

The program below illustrates the pow.invert() function in D3.js:

Example 1: Taking all elements of range to be positive.

HTML

<!DOCTYPE html> 
<html lang="en"> 
<head> 
  <meta charset="UTF-8" /> 
  <meta name="viewport" 
        content="width=device-width, 
                 initial-scale=1.0" /> 
  <title>GeeksforGeeks</title> 
  <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> 
  <h2 style="color: green">GeeksforGeeks</h2> 
    
<p>pow.invert() Function </p> 
  
  <script> 
    var pow = d3.scalePow() 
      .domain([0, 1]) 
      .range([1, 2, 3, 4, 5, 6]); 
  
    document.write("<h3> pow.invert(1): " +  
                   pow.invert(1) + "</h3>"); 
    document.write("<h3>pow.invert(2): " + 
                   pow.invert(2) + "</h3>"); 
    document.write("<h3>pow.invert(3): " +  
                   pow.invert(3) + "</h3>"); 
    document.write("<h3> pow(pow.invert(1)): " +  
                   pow(pow.invert(1)) + "</h3>"); 
    document.write("<h3>pow(pow.invert(2)): " + 
                   pow(pow.invert(2)) + "</h3>"); 
    document.write("<h3>pow(pow.invert(3)): " + 
                   pow(pow.invert(3)) + "</h3>"); 
  </script> 
</body> 
</html>

Output:

Example 2: Taking a range array such that it contains positive and negative numbers both.

HTML

<!DOCTYPE html> 
<html lang="en"> 
<head> 
  <meta charset="UTF-8" /> 
  <meta name="viewport" 
        content="width=device-width, 
                 initial-scale=1.0" /> 
  <title>GeeksforGeeks</title> 
  <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> 
  <h2 style="color: green">GeeksforGeeks</h2> 
    
<p>pow.invert() Function </p> 
  
  <script> 
    var pow = d3.scalePow() 
      .domain([-1, 1]) 
      .rangeRound([10, 20, 30, 40, 50, 60]) 
      .exponent(2); 
  
    document.write("<h3> pow.invert(1): " + 
                   pow.invert(1) + "</h3>"); 
    document.write("<h3>pow.invert(2): " + 
                   pow.invert(2) + "</h3>"); 
    document.write("<h3>pow.invert(3): " +  
                   pow.invert(3) + "</h3>"); 
    document.write("<h3> pow(pow.invert(-1)): " + 
                   pow(pow.invert(-1)) + "</h3>"); 
    document.write("<h3>pow(pow.invert(-2)): " + 
                   pow(pow.invert(-2)) + "</h3>"); 
    document.write("<h3>pow(pow.invert(-1)): " +  
                   pow(pow.invert(-3)) + "</h3>"); 
  </script> 
</body> 
</html>