d3.js area.defined()用法及代码示例

这个d3.area.defined()方法使您可以指定是否为给定数据点定义了数据。如果此方法返回false，则表示存在数据点，否则为true。

用法:

d3.area.defined(data_point)

参数：该函数接受如上所述和以下描述的单个参数。

data_point:此参数是data_point被检查。

返回值：此方法返回一个布尔值。

范例1：

HTML

<!DOCTYPE html> 
<html> 
<head> 
    <meta charset="utf-8"> 
  
    <script src= 
"https://cdnjs.cloudflare.com/ajax/libs/d3/4.2.2/d3.min.js"> 
    </script> 
</head> 
  
<body> 
    <h1 style="text-align:center; color:green;"> 
        GeeksforGeeks 
    </h1> 
  
    <h3 style="text-align:center;"> 
        D3.js | d3.area.defined() Method 
    </h3> 
  
    <center> 
        <svg id="gfg" width="200" height="200"> 
        </svg> 
    </center> 
  
    <script> 
        var data = [ 
          {x:50, y:10}, 
          {x:150, y:30}, 
          {x:200, y:150}, 
          {x:250, y:10}, 
          {x:300, y:150}, 
          {x:350, y:50}, 
          {x:400, y:190}]; 
  
        var xScale = d3.scaleLinear() 
            .domain([0, 8]).range([25, 200]); 
        var yScale = d3.scaleLinear() 
            .domain([0,20]).range([200, 25]); 
  
        var Gen = d3.area() 
          .x((p) => p.x) 
          .y0((p) => p.y*2) 
          .y1((p) => p.y*4) 
          
          // Excluding 3rd index 
          .defined((d,i) => (i != 3)); 
  
        d3.select("#gfg") 
          .append("path") 
          .attr("d", Gen(data)) 
          .attr("fill", "green") 
          .attr("stroke", "black"); 
    </script> 
</body> 
  
</html>

输出：

范例2：

HTML

<!DOCTYPE html> 
<html> 
<head> 
    <meta charset="utf-8"> 
  
    <script src= 
"https://cdnjs.cloudflare.com/ajax/libs/d3/4.2.2/d3.min.js"> 
    </script> 
</head> 
  
<body> 
    <h1 style="text-align:center; color:green;"> 
        GeeksforGeeks 
    </h1> 
  
    <h3 style="text-align:center;"> 
        D3.js | d3.area.defined() Method 
    </h3> 
  
    <center> 
        <svg id="gfg" width="250" height="200"></svg> 
    </center> 
  
    <script> 
        var points = [ 
          {xpoint:25,  ypoint:150}, 
          {xpoint:75,  ypoint:50}, 
          {xpoint:100, ypoint:150}, 
          {xpoint:100, ypoint:50}, 
          {xpoint:200, ypoint:150}]; 
  
  
        var Gen = d3.area() 
          .x((p) => p.xpoint) 
          .y0((p) => p.ypoint/2) 
          .y1((p) => p.ypoint) 
          
          // Excluding 2nd index 
          .defined((d,i) => (i != 2)); 
  
        d3.select("#gfg") 
          .append("path") 
          .attr("d", Gen(points)) 
          .attr("fill", "green") 
          .attr("stroke", "black"); 
  
    </script> 
</body> 
  
</html>

输出：

相关用法

注：本文由纯净天空筛选整理自taran910大神的英文原创作品 D3.js area.defined() Method。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。