D3.js zoom.transform()函数

D3.js中的zoom.transform()函数用于将选中元素的当前缩放变换设置为指定的变换。

句法：

zoom.transform(selection, transform[, point]);

参数：此函数接受如上所述和如下所述的单个参数：

• selection：该参数可以是选择或过渡。
• transform：此参数可以定义为缩放变换或函数。

返回值：此函数返回缩放变换。

下面的程序说明了D3.js中的zoom.transform()函数

示例 1：

 
 
 
    
     
     
    
        svg text {  
            fill: green;  
            font: 20px sans-serif;  
            text-anchor: center;  
        }  
          
        rect {
          pointer-events: all;
        }
    
  
 
    
         
            Geeksforgeeks 
         
      
        D3.js | zoom.transform() 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);
               
            // Call the Zoom.
            var rect = svg.append("rect")
              .attr("width", width)
              .attr("height", height)
              .attr("fill", "none")
              .call(zoom);
                          
            d3.select("#reset")
              .on("click", function() {
                // Create an identity transform
                var transform = d3.zoomIdentity;
                  
                // Apply 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：

 
 
 
        
     
     
    
        rect {
          cursor: pointer;
        }
    
 
 
    
         
            Geeksforgeeks 
         
      
        D3.js | zoom.transform() Function
          
        Trigger Zoom 
         Zoom Level: 
        
          
        
           
        
            var scale = d3.scaleSqrt()  
                .range(["green", "purple", "blue"])
                .domain([1, 40, 1600]);
              
            var zoom = d3.zoom()        
                .on("zoom", zoomed)
                .scaleExtent([1, 1600])
              
            var rect = d3.select("svg")
                .append("rect")
                .attr("width", 400)
                .attr("height", 300)
                .attr("fill", "green")
                .call(zoom);
              
            rect.call(zoom.transform, d3.zoomIdentity);
              
            d3.select("button").on("click", function() {
                var newTransform = d3.zoomIdentity.scale(100);
                rect.call(zoom.transform, newTransform);
            })
              
            // Zoom function:
            function zoomed(){
              var k = d3.event.transform.k;
              rect.attr("fill", scale(k));
              d3.select("#GFG").text(k);
            }
         
    
 
 

输出：