如何突出显示d3 js中从根到所选节点的路径? [英] How to highlight path from root to selected node in d3 js?

问题描述

我已经使用d3 js创建了一棵树.现在，我创建了一个下拉菜单，其中包含树中所有节点的列表.现在，从下拉菜单中选择一个节点，我想突出显示从根到该特定节点的路径.该怎么做?

I have created a tree using d3 js. Now i have created a drop-down menu containing list of all the nodes in the tree. Now on selecting a node from the drop down menu,i want to highlight path from root to that particular node. How to do this?

推荐答案

首先创建一个flatten函数，该函数将分层数据转换为n数组.

First make a flatten function which will make the hierarchical data into a n array.

function flatten(root) {
  var nodes = [],
    i = 0;

  function recurse(node) {
    if (node.children) node.children.forEach(recurse);
    if (node._children) node._children.forEach(recurse);
    if (!node.id) node.id = ++i;
    nodes.push(node);
  }

  recurse(root);
  return nodes;
}

在选择框上添加如下所示的更改侦听器:

On the select box add a change listener like this:

var select = d3.select("body")
      .append("select")
      .on("change", function() {
    //get the value of the select
    var select = d3.select("select").node().value;
    //find selected data from flattened root record
    var find = flatten(root).find(function(d) {
      if (d.name == select)
        return true;
    });
    //reset all the data to have color undefined.
    flatten(root).forEach(function(d) {
      d.color = undefined;
    })
    //iterate over the selected node and set color as red.
    //till it reaches it reaches the root
    while (find.parent) {
      find.color = "red";
      find = find.parent;
    }
    update(find);//call update to reflect the color change
      });

在更新功能中，根据数据(在选择功能中设置)为路径着色，如下所示:

Inside your update function color the path according to the data (set in the select function) like this:

d3.selectAll("path").style("stroke", function(d) {
          if (d.target.color) {
            return d.target.color;//if the value is set
          } else {
            return "gray"
          }
        })

工作代码此处.

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