D3.js scalePoint()函数

d3.scalepoint()函数用于创建并返回具有特定域和范围、无舍入、无填充和中心对齐的新点比例。

句法：

d3.scalePoint([[domain, ]range]);

参数：此函数采用上面给出的两个参数，如下所述：

• 域：它定义了比例的最小值和最大值。默认情况下，域包含一个空数组。
• range：域映射中的每个值都具有范围内的值。默认范围为 [0,1]。

返回值：此函数不返回任何内容。

示例 1：

HTML

  

    
    
  
    
    

  

    
        // Creating the point scale with
        // specified domain and range.
        var point = d3.scalePoint()
  
            // Setting domain for the scale
            .domain(["red", "green", "black", "blue"])
          
            // Setting the range for the scale.
            .range([0.1, 0.2, 0.3, 0.4, 0.5]);
  
        console.log("point(red)", point("red"));
        console.log("point(black)", point("black"));
        console.log("point(green)", point("green"));
        console.log("point(blue)", point("blue"));
    

  

输出：

示例 2：

HTML

  

    
    
  
    
    

  

    
        // Creating the point scale with
        // specified domain and range.
        var point = d3.scalePoint()
  
            // Setting domain for the scale
            .domain([0, 1, 2, 3, 4, 5, 6])
          
            // Setting the range for the scale.
            .range([3, 4, 0.5]);
  
        console.log("point(1)", point("1"));
        console.log("point(3)", point("3"));
        console.log("point(5)", point("5"));
    

  

输出：