What is D3.js zoom.interpolate() Function?

In this article, we will learn D3.js zoom.interpolate() Function,This free D3.js tutorial for complete beginners will help you learn D3.js from scratch.

D3.js zoom.interpolate() Function - ❤️D3.js Tutorials In 2024

The zoom.interpolate() function in D3.js library is used to set the interpolation factory for zoom transitions to the specified function. To apply direct interpolation between two views, try d3.interpolate instead.

Syntax:

 zoom.interpolate([interpolate])

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

interpolate: This parameter is the duration for zoom transitions.

Return Value: This function returns the zoom behavior.

Below program illustrate the zoom.interpolate() function in D3.js library.

Example 1:

HTML

<!DOCTYPE html>
<html>
 
<head>
    <meta charset="utf-8">
 
    <script src=
        "https://d3js.org/d3.v5.js">
    </script>
 
    <style>
        rect {
            fill: blue;
            opacity: 0.5;
            stroke: black;
            stroke-width: 1px;
        }
 
        svg {
            border: 1px solid;
            font: 13px sans-serif;
        }
    </style>
 
</head>
 
<body>
    <center>
        <h1 style="color: green;">
            w3wiki
        </h1>
 
        <h3>D3.js | zoom.interpolate() Function</h3>
 
        <div id="GFG">
        </div>
 
        <script>
            var width = 400;
            var height = 250;
            var length = 30;
 
            var numrects = 100;
            var rects = [];
 
            for (var i = 0; i < numrects; i++)
                rects.push({
                    'x': 1 + Math.floor(Math.random() * width),
                    'y': 1 + Math.floor(Math.random() * height),
                    'h': 3 + Math.floor(Math.random() * length),
                    'w': 3 + Math.floor(Math.random() * length)
                });
 
            var zoomed = d3.zoom()
                .interpolate(d3.interpolate)
                .on('zoom', function (d) {
                    g.attr('transform',
                        d3.event.transform);
                });
 
 
            var svg = d3.select('#GFG')
                .append('svg')
                .attr('width', width)
                .attr('height', height)
 
            var g = svg.append('g')
 
            g.selectAll('rect')
                .data(rects)
                .enter()
                .append('rect')
                .attr('x', function (d) { return d.x; })
                .attr('y', function (d) { return d.y; })
                .attr('height', function (d) { return d.h; })
                .attr('width', function (d) { return d.w; })
                .classed('no-zoom', true)
 
            svg.call(zoomed);
        </script>
    </center>
</body>
 
</html>

Output:

Example 2:

HTML

<!DOCTYPE html> 
<html> 
<head> 
    <meta charset="utf-8">
     <script src="https://d3js.org/d3.v4.min.js"> 
    </script>
        
    <script src=
    "https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js">
    </script>
       
    <style>
        #svg {
            background-color: rgb(149, 160, 230);
        }
        #shape {
            fill: rgb(232, 7, 228);
            stroke: white;
            stroke-width: 3px;
        }
        #shape:hover {
            fill: rgb(13, 214, 30);
        }
    </style>
</head> 
       
<body> 
    <center>
        <h1 style="color: green;"> 
            w3wiki 
        </h1> 
         
        <h3>D3.js | zoom.interpolate() Function</h3>
           
        <div id="GFG"></div>
           
        <script>
            var width = 300,
              height = 200;
               
            var container = d3.select("#GFG").append("div");
               
            var svg = container.append("svg")
                .attr("id", "svg")
                .attr("width", width)
                .attr("height", height);
               
            var group = svg.append("g");
               
            var shape = group.append("rect")
                   .attr("id", "shape")
                   .attr("width", 50)
                   .attr("height", 33)
                   .attr("x", 125)
                   .attr("y", 75);
               
            zoom = d3.zoom()
              .interpolate([1, 3])
              .interpolate(d3.interpolateZoom)
              .translateExtent([[0, 0], [width, height]])
              .on("zoom", zoomed);
               
            svg.call(zoom);
               
            function zoomed() {
            change = d3.event.transform;
            group.attr("transform", "translate("
            + [change.x, change.y] + ")scale(" + change.k + ")")
            group.select("#shape").style("stroke-width", 
             (3 / change.k) + "px");
            }
        </script> 
    </center>
</body>    
</html>

Output: