D3.js zoomIdentity() Function

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The d3.zoomIdentity() function in D3.js is used to get the identity transform, where k = 1, t_x = t_y = 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;">  
            Geeksforzambiatek  
        </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;">  
            Geeksforzambiatek  
        </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>