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.
<!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.
<!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>
Output:
