d3.js brush.clear()用法及代码示例

D3.js中的brush.clear()函数用于设置指定组上画笔的活动选择。它是带有null选择的brush.move的别名。

用法:

brush.clear(group);

参数：该函数接受如上所述和以下描述的单个参数

group:此参数是在其上实现画笔的指定组。

返回值：此函数返回定义该元素的笔刷选择的数组。

以下示例程序旨在说明D3.js中的brush.clear()函数

范例1：

HTML

<!DOCTYPE html>   
<html>   
        
<head>   
    <script src= 
        "https://d3js.org/d3.v5.min.js"> 
    </script>  
</head>   
    
<body>   
    <center> 
        <h1 style="color:green;">GeeksForGeeks</h1> 
  
        <h3>D3.js | brush.clear() Function  </h3> 
          
        <button>Click</button> 
        <br> 
        <br> 
        <svg width="500" height="100" 
             style="background-color:#aaf2ef;"> 
        </svg>  
          
        <script>   
            // Selecting SVG element  
            const svg = d3.select("svg"); 
              
            const g = svg.append("g"); 
              
            // Creating a brush using the   
            // d3.brush function  
            g.call(d3.brush()); 
              
            // Use of brush.move() function 
            d3.select("button").on("click", function() { 
                g.call(d3.brush().clear) 
            });      
        </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>  
      
    <style> 
  
        circle { 
          fill-opacity:0.2; 
        } 
          
        circle.active { 
          fill-opacity:0.8; 
          stroke:red; 
          fill:green; 
        } 
  
    </style> 
</head>   
    
<body>   
    <center> 
        <h1 style="color:green;">GeeksForGeeks</h1> 
  
        <h3>D3.js | brush.clear() Function  </h3> 
          
        <svg width="500" height="200"></svg> 
          
        <script>   
            var data = d3.range(50).map(Math.random); 
  
            var svg = d3.select("svg"), 
                margin = {top:10, right:50, 
                        bottom:50, left:50}, 
                width = +svg.attr("width") -  
                        margin.left - margin.right, 
                height = +svg.attr("height") -  
                        margin.top - margin.bottom, 
                g = svg.append("g") 
                    .attr("transform", "translate("  
                    + margin.left + "," + margin.top + ")" 
                    ); 
  
            var x = d3.scaleLinear().range([0, width]), 
                y = d3.randomNormal(height / 2, height / 8), 
                z = d3.scaleLinear().range([0, height]); 
  
            var brush = d3.brushX() 
                .extent([[0, 0], [width, height]]) 
                .on("start brush end", brushmoved); 
  
            g.append("g") 
                .attr("class", "axis axis--x") 
                .attr("transform", "translate(0,0)") 
                .call(d3.axisLeft(z).ticks(3)); 
  
            var circle = g.append("g") 
                .attr("class", "circle") 
                .selectAll("circle") 
                .data(data) 
                .enter().append("circle") 
                .attr("transform", function (d) {  
                    return "translate("  
                    + x(d) + "," + y() + ")";  
                }) 
                .attr("r", 10); 
  
            var gBrush = g.append("g") 
                .attr("class", "brush") 
                .call(brush); 
  
            gBrush.call(brush.clear); 
  
            var bs = ""; 
            function brushmoved() { 
              var s = d3.event.selection; 
                
              if (d3.event.type === "start"){ 
                bs = d3.event.selection; 
              }  
              else if (d3.event.type === "end"){ 
                  
                if (bs[0] !== s[0] && bs[1] !== s[1]) { 
                  console.log('moved both'); 
                }  
                else if (bs[0] !== s[0]) { 
                  console.log('moved left'); 
                }  
                else { 
                  console.log('moved right'); 
                } 
              } 
                
              if (s == null) { 
                handle.attr("display", "none"); 
                circle.classed("active", false); 
              }  
              else { 
                var sx = s.map(x.invert); 
                circle.classed("active", function (d) { 
                    return sx[0] <= d && d <= sx[1];  
                }); 
                handle.attr("display", null) 
                .attr("transform", function (d, i) { 
                    return "translate(" 
                    + s[i] + "," + height / 2 + ")";  
                }); 
              } 
            } 
              
        </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 brush.clear() 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。