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D3.js zoomIdentity() Function

  • Last Updated : 06 Sep, 2020
Geek Week

The d3.zoomIdentity() function in D3.js is used to get the identity transform, where k = 1, tx = ty = 0.

Syntax:

d3.zoomIdentity;

Parameters: This function does not accept any parameter.

Return Value: This function returns the identity transform.

Below programs illustrate the d3.zoomIdentity() function in D3.js.



Example 1:

HTML




<!DOCTYPE html> 
<html>
    
<head
    <meta charset="utf-8">
       
    <script src=
        "https://d3js.org/d3.v4.min.js"
    </script>
       
    <style>
        svg text {  
            fill: green;  
            font: 20px sans-serif;  
            text-anchor: center;  
        }  
           
        rect {
          pointer-events: all;
        }
    </style>
</head
     
<body
    <center>
        <h1 style="color: green;"
            Geeksforgeeks 
        </h1
       
        <h3>D3.js | d3.zoomIdentity() Function</h3>
           
        <button id="reset">Reset</button><br/>
           
        <svg></svg>
           
        <script>
            var width = 400;
            var height = 200;
               
            var svg = d3.select("svg")
              .attr("width",width)
              .attr("height",height);
                 
            // The scale used to display the axis.
            var scale = d3.scaleLinear()
              .range([10,width-20])
              .domain([0,100]);
                
            var shadowScale = scale.copy();
               
            var axis = d3.axisBottom()
              .scale(scale);
                 
            var g = svg.append("g")
              .attr("transform","translate(0,50)")
              .call(axis);
                 
            // Standard zoom behavior
            var zoom = d3.zoom()
              .scaleExtent([1,10])
              .translateExtent([[0, 0], [width, height]])
              .on("zoom", zoomed);
                
            // Calling the Zoom
            var rect = svg.append("rect")
              .attr("width",width)
              .attr("height",height)
              .attr("fill","none")
              .call(zoom);
                           
            d3.select("#reset")
              .on("click", function() {
  
                // Creating an identity transform
                var transform = d3.zoomIdentity;
                   
                // Applying the transform:
                rect.call(zoom.transform, transform);
              })
  
            function zoomed() {
              var t = d3.event.transform;
              scale.domain(t.rescaleX(shadowScale).domain());
              g.call(axis);
            }
        </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
</head
      
<body
    <center>
        <h1 style="color: green;"
            Geeksforgeeks 
        </h1
        
        <h3>D3.js | d3.zoomIdentity() Function</h3>
            
        <script>
            var svg = d3.select("body").append("svg")
               .attr("width", 400)
               .attr("height", 300);
                  
            var g1 = svg.append("g");
               
            var zoom1 = d3.zoom().on("zoom", function() { 
               g1.attr("transform", d3.event.transform);
            });
               
            g1.call(zoom1.transform, d3.zoomIdentity  
                   .translate(150, 100)
                   .scale(2));
               
            g1.append("rect")
               .attr("x", 20)
               .attr("y", 20)
               .attr("width", 60)
               .attr("height", 60)
               .attr("fill","green");
                  
            d3.selectAll("rect").on("click", function() {
   
               g1.transition()
                  .duration(3000)
                  .attr("transform", d3.zoomIdentity)
                  .on("end", function() {
                        d3.select(this)
                        .call(zoom1.transform, d3.zoomIdentity);   
                })
            });
        </script
    </center>
</body
    
</html>

Output:

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