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javascript - 如何删除 d3.js 树中的初始转换

问题描述

我是 d3.js 的新手。我正在使用这个树形图 https://bl.ocks.org/d3noob/8375092 并且我想删除树元素的初始转换（从 x，y 0）到它们的树结构中。我试过改变这一行：

 var nodeEnter = node.enter().append("g")
      .attr("class", "node")
      .attr("transform", function(d) { return "translate(" + source.y0 + "," + source.x0 + ")"; })
      .on("click", click);

至

 var nodeEnter = node.enter().append("g")
      .attr("class", "node")
      .attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
      .on("click", click);

它将树元素设置在没有过渡的位置，但是当我折叠元素时，我没有得到过渡（我确实想要）。

所以我的问题是：如何在不改变折叠/打开过渡行为的情况下删除树的初始过渡。

标签： javascriptd3.js

解决方案

一个非常简单的解决方案（需要在代码中进行最少的重构）将使用一个布尔值（此处命名为animate）作为 中的第二个参数update，您将使用它来设置转换的延迟。像这样：

.duration(animate ? duration : 0)

然后，你就update(node, boolean)随心所欲。这是演示：

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="utf-8">

  <title>Tree Example</title>

  <style>
    .node {
      cursor: pointer;
    }
    
    .node circle {
      fill: #fff;
      stroke: steelblue;
      stroke-width: 3px;
    }
    
    .node text {
      font: 12px sans-serif;
    }
    
    .link {
      fill: none;
      stroke: #ccc;
      stroke-width: 2px;
    }
  </style>

</head>

<body>

  <!-- load the d3.js library -->
  <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.17/d3.min.js"></script>

  <script>
    var treeData = [{
      "name": "Top Level",
      "parent": "null",
      "children": [{
          "name": "Level 2: A",
          "parent": "Top Level",
          "children": [{
              "name": "Son of A",
              "parent": "Level 2: A"
            },
            {
              "name": "Daughter of A",
              "parent": "Level 2: A"
            }
          ]
        },
        {
          "name": "Level 2: B",
          "parent": "Top Level"
        }
      ]
    }];


    // ************** Generate the tree diagram	 *****************
    var margin = {
        top: 20,
        right: 120,
        bottom: 20,
        left: 120
      },
      width = 960 - margin.right - margin.left,
      height = 500 - margin.top - margin.bottom;

    var i = 0,
      duration = 750,
      root;

    var tree = d3.layout.tree()
      .size([height, width]);

    var diagonal = d3.svg.diagonal()
      .projection(function(d) {
        return [d.y, d.x];
      });

    var svg = d3.select("body").append("svg")
      .attr("width", width + margin.right + margin.left)
      .attr("height", height + margin.top + margin.bottom)
      .append("g")
      .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

    root = treeData[0];
    root.x0 = height / 2;
    root.y0 = 0;

    update(root, false);

    d3.select(self.frameElement).style("height", "500px");

    function update(source, animate) {

      // Compute the new tree layout.
      var nodes = tree.nodes(root).reverse(),
        links = tree.links(nodes);

      // Normalize for fixed-depth.
      nodes.forEach(function(d) {
        d.y = d.depth * 180;
      });

      // Update the nodes…
      var node = svg.selectAll("g.node")
        .data(nodes, function(d) {
          return d.id || (d.id = ++i);
        });

      // Enter any new nodes at the parent's previous position.
      var nodeEnter = node.enter().append("g")
        .attr("class", "node")
        .attr("transform", function(d) {
          return "translate(" + source.y0 + "," + source.x0 + ")";
        })
        .on("click", click);

      nodeEnter.append("circle")
        .attr("r", 1e-6)
        .style("fill", function(d) {
          return d._children ? "lightsteelblue" : "#fff";
        });

      nodeEnter.append("text")
        .attr("x", function(d) {
          return d.children || d._children ? -13 : 13;
        })
        .attr("dy", ".35em")
        .attr("text-anchor", function(d) {
          return d.children || d._children ? "end" : "start";
        })
        .text(function(d) {
          return d.name;
        })
        .style("fill-opacity", 1e-6);

      // Transition nodes to their new position.
      var nodeUpdate = node.transition()
        .duration(animate ? duration : 0)
        .attr("transform", function(d) {
          return "translate(" + d.y + "," + d.x + ")";
        });

      nodeUpdate.select("circle")
        .attr("r", 10)
        .style("fill", function(d) {
          return d._children ? "lightsteelblue" : "#fff";
        });

      nodeUpdate.select("text")
        .style("fill-opacity", 1);

      // Transition exiting nodes to the parent's new position.
      var nodeExit = node.exit().transition()
        .duration(duration)
        .attr("transform", function(d) {
          return "translate(" + source.y + "," + source.x + ")";
        })
        .remove();

      nodeExit.select("circle")
        .attr("r", 1e-6);

      nodeExit.select("text")
        .style("fill-opacity", 1e-6);

      // Update the links…
      var link = svg.selectAll("path.link")
        .data(links, function(d) {
          return d.target.id;
        });

      // Enter any new links at the parent's previous position.
      link.enter().insert("path", "g")
        .attr("class", "link")
        .attr("d", function(d) {
          var o = {
            x: source.x0,
            y: source.y0
          };
          return diagonal({
            source: o,
            target: o
          });
        });

      // Transition links to their new position.
      link.transition()
        .duration(animate ? duration : 0)
        .attr("d", diagonal);

      // Transition exiting nodes to the parent's new position.
      link.exit().transition()
        .duration(duration)
        .attr("d", function(d) {
          var o = {
            x: source.x,
            y: source.y
          };
          return diagonal({
            source: o,
            target: o
          });
        })
        .remove();

      // Stash the old positions for transition.
      nodes.forEach(function(d) {
        d.x0 = d.x;
        d.y0 = d.y;
      });
    }

    // Toggle children on click.
    function click(d) {
      if (d.children) {
        d._children = d.children;
        d.children = null;
      } else {
        d.children = d._children;
        d._children = null;
      }
      update(d, true);
    }
  </script>

</body>

</html>

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