D3.js zoomIdentity()函数

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 。

句法：

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。

下面的程序说明了D3.js中的d3.zoomIdentity()函数。

示例 1：

HTML

 

    
 
    
       
     
    
       
    
        svg text {  
            fill: green;  
            font: 20px sans-serif;  
            text-anchor: center;  
        }  
           
        rect {
          pointer-events: all;
        }
    
 
     
 
    
         
            Geeksforgeeks 
         
       
        D3.js | d3.zoomIdentity() Function
           
        Reset
           
        
           
        
            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);
            }
         
    
 
   

输出：

示例 2：

HTML

 
 
    
 
     
    
     
     
 
      
 
    
         
            Geeksforgeeks 
         
        
        D3.js | d3.zoomIdentity() Function
            
        
            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);   
                })
            });
         
    
 
    

输出：