D3.js point.copy()函数

point.copy()函数用于构造并返回当前比例的副本。对任一比例所做的任何更改都是相互独立的，即复制比例的更改不会影响原始比例，反之亦然。

句法：

point.copy();

参数：此函数不接受任何参数。

返回值：此函数返回当前比例的副本。返回类型是一个函数。

下面给出了上面给出的函数的几个例子。

示例 1：

 
 
 
     
     
    GeekforGeeks 
    
    
      
 
 
     
// Creating the point scale with specified domain and range.
        var point = d3.scalePoint()
                    .domain([1, 2, 3, 4])
                    .range([1, 5]);
        var copyScale = point.copy();
        console.log("From original scale: ");
        console.log("point(1): ", point(1));
        console.log("point(2): ", point(2));
        console.log("From copy scale: ");
        console.log("copyScale(1): ", copyScale(1));
        console.log("copyScale(2): ", copyScale(2));
          
     
 

输出：

示例 2：

 
 
 
     
     
    GeekforGeeks 
    
    
      
 
 
     
// Creating the point scale with specified domain and range.
        var point = d3.scalePoint()
                    .domain([1, 2, 3, 4])
                    .range([1, 5]);
  
        console.log("From original scale befire making changes: ");
        console.log("point(1): ", point(1));
        console.log("point(2): ", point(2));
        // Making copy of the original scale
        var copyScale = point.copy();
        point.round([1, 5]);
        console.log("From original scale after making changes: ");
        console.log("point(1): ", point(1));
        console.log("point(2): ", point(2));
  
        console.log("From copy scale: ");
        // Changes in original scale does not
        // Affect copy scale
        console.log("copyScale(1): ", copyScale(1));
        console.log("copyScale(2): ", copyScale(2));
          
     
 

输出：