d3.js zoomIdentity()用法及代码示例

D3.js中的d3.zoomIdentity()函数用于获取恒等变换，其中k = 1，t_x=t_y= 0。

用法:

d3.zoomIdentity;

参数：此函数不接受任何参数。

返回值：此函数返回身份转换。

以下程序说明了D3.js中的d3.zoomIdentity()函数。

范例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>

输出：

范例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>

输出：

相关用法

注：本文由纯净天空筛选整理自SHUBHAMSINGH10大神的英文原创作品 D3.js zoomIdentity() Function。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。