如何将缩放添加到 d3 可折叠树示例？答案

【问题标题】：How can I add zooming to the d3 collapsible tree example?如何将缩放添加到 d3 可折叠树示例？
【发布时间】：2013-09-18 02:47:57
【问题描述】：

我正在尝试向 d3 可折叠树 example 添加缩放功能，但无法使其正常工作。我知道有一个关于这个here 的问题，尽管它看起来相当彻底，但我的更改不起作用。我唯一得到的是一个白页。可能与我对 javascript/d3 比较陌生的事实有关。这是我的代码。

<!DOCTYPE html>
<meta charset="utf-8">
<style>

svg {
    pointer-events: all;
}

.node {
  cursor: pointer;
}

.node circle {
  fill: #fff;
  stroke: steelblue;
  stroke-width: 1.5px;
}

tree {
pointer-events: all;
}

.node text {
  font: 12px sans-serif;
}

.link {
  fill: none;
  stroke: #ccc;
  stroke-width: 1.5px;
}



</style>
<body>
<script src="d3.v3.min.js"></script>
<script>

var margin = {top: 20, right: 120, bottom: 20, left: 120},
    width = 1500 - margin.right - margin.left,
    height = 800 - 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 + ")")

d3.json("flare.json", function(error, flare) {
  root = flare;
  root.x0 = height / 2;
  root.y0 = 0;

  function collapse(d) {
    if (d.children) {
      d._children = d.children;
      d._children.forEach(collapse);
      d.children = null;
    }
  }

  root.children.forEach(collapse);
  update(root);
});

d3.select(self.frameElement).style("height", "800px");

function update(source) {

  // 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 ? -10 : 10; })
      .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(duration)
      .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });

  nodeUpdate.select("circle")
      .attr("r", 4.5)
      .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(duration)
      .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;
  });

    d3.select("svg")
    .call(d3.behavior.zoom()
          .scaleExtent([0.5, 5])
          .on("zoom", zoom));


}

// 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);


function zoom() {
    var scale = d3.event.scale,
        translation = d3.event.translate,
        tbound = -h * scale,
        bbound = h * scale,
        lbound = (-w + m[1]) * scale,
        rbound = (w - m[3]) * scale;
    // limit translation to thresholds
    translation = [
        Math.max(Math.min(translation[0], rbound), lbound),
        Math.max(Math.min(translation[1], bbound), tbound)
    ];
    d3.select(".drawarea")
        .attr("transform", "translate(" + translation + ")" +
              " scale(" + scale + ")");
}




}

</script>

为什么缩放实现不起作用？

【问题讨论】：

您在zoom 函数中选择的drawarea 类似乎没有。

标签： javascript tree d3.js zooming

【解决方案1】：

我玩了一下你的代码，发现了几个潜在的问题：

根据您运行它的位置/方式，加载flare.json 文件可能会导致CORS 错误（例如，如果您尝试链接到bostock github 上的那个）。您可以将 json 对象直接嵌入到 'flare' 变量中，然后只需将 d3.json() 方法中的代码移动到脚本底部并将根变量分配给flare。

var flare =  ...paste contents of flare.json here... ;

您的 javascript 方法是按照您在定义之前引用方法的顺序定义的（您应该在更新方法之前移动缩放和单击方法）：

collapse(d){...}
zoom(){...}
click(){...}
update(){...}

您的缩放方法引用了未在任何地方定义的“h”、“w”和“m”。我假设它们应该是宽度、高度和边距：

var zoom = function() {
    var scale = d3.event.scale,
        translation = d3.event.translate,
        tbound = -height * scale,
        bbound = height * scale,
        lbound = (-width + margin.right) * scale,
        rbound = (width - margin.left) * scale;

最后，要修复缩放问题，您应该像这样修复缩放方法：

var zoom = function() {
    var scale = d3.event.scale,
        translation = d3.event.translate,
        tbound = -height * scale,
        bbound = height * scale,
        lbound = (-width + margin.right) * scale,
        rbound = (width - margin.left) * scale;
    // limit translation to thresholds
    translation = [
        Math.max(Math.min(translation[0], rbound), lbound),
        Math.max(Math.min(translation[1], bbound), tbound)
    ];
    svg.attr("transform", "translate(" + translation + ")" + " scale(" + scale + ")");
}

请注意，我将“select(".drawArea")”替换为“svg”。因为您要转换顶部 g 元素（即“svg”变量中的内容）。

仅供参考 - 我无法在 plnkr 或 jsFiddle 中真正使用它，因为由于在 plnkr 和 jsFiddle 中处理变量/函数范围的方式存在奇怪的 d3 错误（请参阅here）。这可能是其他人可以解决的问题。但这是完整的代码（减去嵌入的flare.json变量）。我在我自己的 Tomcat 容器中运行了这段代码，可以双击树并放大。您可能想尝试缩放和平移，以便树不会在可见窗口的边界之外绘制（现在如果你双击它会放大，但会重新居中，所以树的左侧不在浏览器窗口的一侧）。

<!DOCTYPE html>
<meta charset="utf-8">
<style>

svg {  pointer-events: all;  }
.node { cursor: pointer;  }
.node circle {
    fill: #fff;
    stroke: steelblue;
    stroke-width: 1.5px;
}
tree {  pointer-events: all;  }
.node text {  font: 12px sans-serif;  }
.link {
    fill: none;
    stroke: #ccc;
    stroke-width: 1.5px;
}

</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>

var margin = {top: 20, right: 120, bottom: 20, left: 120},
    width = 1500 - margin.right - margin.left,
    height = 800 - 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 + ")")

d3.select(self.frameElement).style("height", "800px");

var collapse = function(d) {
    if (d.children) {
        d._children = d.children;
        d._children.forEach(collapse);
        d.children = null;
    }
}

var zoom = function() {
    var scale = d3.event.scale,
        translation = d3.event.translate,
        tbound = -height * scale,
        bbound = height * scale,
        lbound = (-width + margin.right) * scale,
        rbound = (width - margin.left) * scale;
    // limit translation to thresholds
    translation = [
        Math.max(Math.min(translation[0], rbound), lbound),
        Math.max(Math.min(translation[1], bbound), tbound)
    ];
    svg.attr("transform", "translate(" + translation + ")" + " scale(" + scale + ")");
}

// Toggle children on click.
var click = function(d) {
    if (d.children) {
        d._children = d.children;
        d.children = null;
    } else {
        d.children = d._children;
        d._children = null;
    }
    update(d);
};

var update = function(source) {
    // 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 ? -10 : 10; })
        .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(duration)
        .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });

    nodeUpdate.select("circle")
        .attr("r", 4.5)
        .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(duration)
        .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;
    });

    d3.select("svg")
        .call(d3.behavior.zoom()
        .scaleExtent([0.5, 5])
        .on("zoom", zoom));
};

d3.json("flare.json", function(json){
    root = json;
    root.x0 = height / 2;
    root.y0 = 0;
    root.children.forEach(collapse);
    update(root);
});

</script>

【讨论】：

【解决方案2】：

Zoom in&out with drag properties are very easy to appy with collapsible tree. Mainly we must add new version of d3 
 <script type="text/javascript" src="resources/d3.v3.js"></script>
 <script type="text/javascript" src="resources/d3.v3.min.js"></script>
Are available in [http://d3js.org/][1]


 var vis = d3.select("#box").append("svg:svg")
        .attr("class","svg_container")
        .attr("width", w)
        .attr("height", h)
        .style("overflow", "scroll")
        .style("background-color","#EEEEEE")
        .append("svg:g")
        .attr("class","drawarea")
        .append("svg:g")
        .attr("transform", "translate(" + m[3] + "," + m[0] + ")");

    d3.select("svg")   //applying zoom in&out for svg
            .call(d3.behavior.zoom()
                  .scaleExtent([0.5, 5])
                  .on("zoom", zoom));

    function zoom() {  //zoom in&out function 
        var scale = d3.event.scale,
            translation = d3.event.translate,
            tbound = -h * scale,
            bbound = h * scale,
            lbound = (-w + m[1]) * scale,
            rbound = (w - m[3]) * scale;
        // limit translation to thresholds
        translation = [
            Math.max(Math.min(translation[0], rbound), lbound),
            Math.max(Math.min(translation[1], bbound), tbound)
        ];
        d3.select(".drawarea")
            .attr("transform", "translate(" + translation + ")" +
                  " scale(" + scale + ")");
    }

【讨论】：