强制布局放大在拖动或zomming的第一个刻度重置 [英] Force layout zoom resets on first tick of dragging or zomming

问题描述

我试图使用d3 v4实现强制布局图，我有一个问题，在这些函数的第一个勾的图形的默认缩放和平移行为。
由于它是一个有点大的图形（约700个节点）我使用d3的 transform（translate（））函数设置初始位置和缩放声明 svg 元素如下：

I'm trying to implement a force layout graph using d3 v4, and I'm having a problem with the default zooming and panning behaviours of the graph on the first tick of these functions. Since it's a somewhat large graph (~700 nodes) I'm using the transform(translate()) function of d3 to set the initial position and zooming after declaring the svg element as so:

var svg = d3.select("svg")
        .call(d3.zoom()
        .scaleExtent([0.05,2])
        .on("zoom", zoomed))
        .append("g"), width = +svg.attr("width"), height = +svg.attr("height");
var initialScale = 0.1,
        zoomWidth = (svg.attr("width")-initialScale*svg.attr("width"))/2,
        zoomHeight = (svg.attr("height")-initialScale*svg.attr("height")/2);

之后，我声明元素的初始位置和缩放比例：

After that, I declare the initial position and scale of the element:

svg.attr（transform，translate（+（zoomWidth + 400）+，+（zoomHeight + 325）+）scale +））;

对于缩放，平移和tick函数，我使用这个Mike Bostock示例。

For the zooming, panning and tick functions, I'm using the code from this Mike Bostock example.

function dragstarted(d) {
    if (!d3.event.active) simulation.alphaTarget(0.3).restart();
    d.fx = d.x ;
    d.fy = d.y;
}
function dragged(d) {
    d.fx = d3.event.x;
    d.fy = d3.event.y;
}
function dragended(d) {
    if (!d3.event.active) simulation.alphaTarget(0);
    d.fx = null;
    d.fy = null;
}
function zoomed() {
    svg.attr("transform", d3.event.transform);
    // Manually offsets the zoom to compensate for the initial position. Should get fixed asap or the position variables made global.
    //svg.attr("transform", "translate(" + (d3.event.transform.x + 400) + "," + (d3.event.transform.y + 325) + ")scale(" +  d3.event.transform.k + ")");
}
function ticked() {
    link
        .attr("x1", function(d) { return d.source.x; })
        .attr("y1", function(d) { return d.source.y; })
        .attr("x2", function(d) { return d.target.x; })
        .attr("y2", function(d) { return d.target.y; });
    gnodes
        .attr("transform", function(d) {
            return "translate(" + [d.x, d.y] + ")";
        });
}

（正如你可以从注释中看到的，点作为修饰符到 zoomed（）函数，但是没有解决任何东西）。

(As you can see from the comment, I even tried manually setting those initial points as modifiers to the zoomed() function, but that didn't solve anything).

问题是，在声明svg之后设置的初始 0.1 缩放第一次拖动或平移可视化（之后，它会正常工作，直到页面重新加载）。它似乎默认一些缩放比例，我似乎不能正确地控制，以便它开始放大从全局设置的 initialScale 值。

The problem is that the initial 0.1 zoom that is set after declaring the svg is being reset whenever you try to drag or pan over the visualization for the first time (after that, it works correctly until the page is reloaded). It seems to default to some zooming scale that I don't seem to be able to control properly so that it starts zooming from the initialScale value that is set globally.

您可以观看此gfycat 行为的gif行为 。

You can watch a gif of the behaviour on this gfycat I made.

我还阅读了这个问题在Stack Overflow的答案，这似乎与我的问题，但我不能实现一个合适的解决方案很少有d3的经验可能是这个的原因，我敢肯定）。因为我直接在svg声明上声明缩放对象，我不知道是否应该在其他地方声明缩放对象，然后手动将它附加到svg，或者我应该这样做（再次，很少的经验） 。

I've also read the answer to this question in Stack Overflow, which seems to be related to my problem, but I can't implement a proper solution (my very little experience with d3 yet might be the cause for this, I'm sure). Since I'm declaring the zoom object directly on the svg declaration, I don't know if I should be declaring the zoom object elsewhere and then manually attaching it to the svg, or how I should do so (again, very little experience).

我一直在战斗了几天，虽然答案可能很简单，但还是无法解决这个问题，所以任何帮助非常感谢。提前感谢。

I've been fighting this for a couple of days and haven't been able to solve this even though the answer might be very simple, so any kind of help would be greatly appreciated. Thanks in advance.

推荐答案

您不应手动设置缩放像你一样：

You shouldn't be manually setting the scale like you are doing with:

svg.attr("transform", "translate(" + (zoomWidth+400) + "," + (zoomHeight+325) + ")scale(" + initialScale + ")");

而是创建 transform 并使用 .call zoom.transform ：

  // initial setup
  var zoom = d3.zoom()
    .scaleExtent([0.05, 2])
    .on("zoom", zoomed);

  var svg = d3.select("svg").call(zoom), //<-- apply zoom to svg
    g = svg.append("g"), //<-- g for append elements, this is what you are zooming
    width = 960,
    height = 600;

  var transform = d3.zoomIdentity //<-- create your transform with your initialScale
    .translate(width / 6, height / 6)
    .scale(0.5);

  svg.call(zoom.transform, transform); //<-- apply your initial transform, this will fire you zoomed event

EDITS FOR评论

分离出 svg 和 g 是这里的svg元素是事件接收器。它是缩放事件处理程序绑定的元素（在大多数 d3 示例中，您将看到一个 rect 元素用于此）。 g 另一方面是正在缩放的​​容器元素。

The reason for separating out the svg and the g is that the svg element here is the event receiver. It is the element to which the zoom event handlers are bound (in most d3 examples, you'll see a rect element being used for this). The g on the other hand, is the container element that's being zoomed.

这里有一个完整的示例：

Here's a full example:

<!DOCTYPE html>
<meta charset="utf-8">
<style>
  .links line {
    stroke: #999;
    stroke-opacity: 0.6;
  }
  
  .nodes circle {
    stroke: #fff;
    stroke-width: 1.5px;
  }
</style>
<svg width="960" height="600"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

  var zoom = d3.zoom()
    .scaleExtent([0.05, 2])
    .on("zoom", zoomed);

  var svg = d3.select("svg").call(zoom),
    g = svg.append("g"),
    width = 960,
    height = 600;
    
  var transform = d3.zoomIdentity
    .translate(width / 6, height / 6)
    .scale(0.5);

  var color = d3.scaleOrdinal(d3.schemeCategory20);

  var simulation = d3.forceSimulation()
    .force("link", d3.forceLink().id(function(d) {
      return d.id;
    }))
    .force("charge", d3.forceManyBody())
    .force("center", d3.forceCenter(width / 2, height / 2));

  svg.call(zoom.transform, transform);

  var graph = {"nodes":[{"id":"Myriel","group":1},{"id":"Napoleon","group":1},{"id":"Mlle.Baptistine","group":1},{"id":"Mme.Magloire","group":1},{"id":"CountessdeLo","group":1},{"id":"Geborand","group":1},{"id":"Champtercier","group":1},{"id":"Cravatte","group":1},{"id":"Count","group":1},{"id":"OldMan","group":1},{"id":"Labarre","group":2},{"id":"Valjean","group":2},{"id":"Marguerite","group":3},{"id":"Mme.deR","group":2},{"id":"Isabeau","group":2},{"id":"Gervais","group":2},{"id":"Tholomyes","group":3},{"id":"Listolier","group":3},{"id":"Fameuil","group":3},{"id":"Blacheville","group":3},{"id":"Favourite","group":3},{"id":"Dahlia","group":3},{"id":"Zephine","group":3},{"id":"Fantine","group":3},{"id":"Mme.Thenardier","group":4},{"id":"Thenardier","group":4},{"id":"Cosette","group":5},{"id":"Javert","group":4},{"id":"Fauchelevent","group":0},{"id":"Bamatabois","group":2},{"id":"Perpetue","group":3},{"id":"Simplice","group":2},{"id":"Scaufflaire","group":2},{"id":"Woman1","group":2},{"id":"Judge","group":2},{"id":"Champmathieu","group":2},{"id":"Brevet","group":2},{"id":"Chenildieu","group":2},{"id":"Cochepaille","group":2},{"id":"Pontmercy","group":4},{"id":"Boulatruelle","group":6},{"id":"Eponine","group":4},{"id":"Anzelma","group":4},{"id":"Woman2","group":5},{"id":"MotherInnocent","group":0},{"id":"Gribier","group":0},{"id":"Jondrette","group":7},{"id":"Mme.Burgon","group":7},{"id":"Gavroche","group":8},{"id":"Gillenormand","group":5},{"id":"Magnon","group":5},{"id":"Mlle.Gillenormand","group":5},{"id":"Mme.Pontmercy","group":5},{"id":"Mlle.Vaubois","group":5},{"id":"Lt.Gillenormand","group":5},{"id":"Marius","group":8},{"id":"BaronessT","group":5},{"id":"Mabeuf","group":8},{"id":"Enjolras","group":8},{"id":"Combeferre","group":8},{"id":"Prouvaire","group":8},{"id":"Feuilly","group":8},{"id":"Courfeyrac","group":8},{"id":"Bahorel","group":8},{"id":"Bossuet","group":8},{"id":"Joly","group":8},{"id":"Grantaire","group":8},{"id":"MotherPlutarch","group":9},{"id":"Gueulemer","group":4},{"id":"Babet","group":4},{"id":"Claquesous","group":4},{"id":"Montparnasse","group":4},{"id":"Toussaint","group":5},{"id":"Child1","group":10},{"id":"Child2","group":10},{"id":"Brujon","group":4},{"id":"Mme.Hucheloup","group":8}],"links":[{"source":"Napoleon","target":"Myriel","value":1},{"source":"Mlle.Baptistine","target":"Myriel","value":8},{"source":"Mme.Magloire","target":"Myriel","value":10},{"source":"Mme.Magloire","target":"Mlle.Baptistine","value":6},{"source":"CountessdeLo","target":"Myriel","value":1},{"source":"Geborand","target":"Myriel","value":1},{"source":"Champtercier","target":"Myriel","value":1},{"source":"Cravatte","target":"Myriel","value":1},{"source":"Count","target":"Myriel","value":2},{"source":"OldMan","target":"Myriel","value":1},{"source":"Valjean","target":"Labarre","value":1},{"source":"Valjean","target":"Mme.Magloire","value":3},{"source":"Valjean","target":"Mlle.Baptistine","value":3},{"source":"Valjean","target":"Myriel","value":5},{"source":"Marguerite","target":"Valjean","value":1},{"source":"Mme.deR","target":"Valjean","value":1},{"source":"Isabeau","target":"Valjean","value":1},{"source":"Gervais","target":"Valjean","value":1},{"source":"Listolier","target":"Tholomyes","value":4},{"source":"Fameuil","target":"Tholomyes","value":4},{"source":"Fameuil","target":"Listolier","value":4},{"source":"Blacheville","target":"Tholomyes","value":4},{"source":"Blacheville","target":"Listolier","value":4},{"source":"Blacheville","target":"Fameuil","value":4},{"source":"Favourite","target":"Tholomyes","value":3},{"source":"Favourite","target":"Listolier","value":3},{"source":"Favourite","target":"Fameuil","value":3},{"source":"Favourite","target":"Blacheville","value":4},{"source":"Dahlia","target":"Tholomyes","value":3},{"source":"Dahlia","target":"Listolier","value":3},{"source":"Dahlia","target":"Fameuil","value":3},{"source":"Dahlia","target":"Blacheville","value":3},{"source":"Dahlia","target":"Favourite","value":5},{"source":"Zephine","target":"Tholomyes","value":3},{"source":"Zephine","target":"Listolier","value":3},{"source":"Zephine","target":"Fameuil","value":3},{"source":"Zephine","target":"Blacheville","value":3},{"source":"Zephine","target":"Favourite","value":4},{"source":"Zephine","target":"Dahlia","value":4},{"source":"Fantine","target":"Tholomyes","value":3},{"source":"Fantine","target":"Listolier","value":3},{"source":"Fantine","target":"Fameuil","value":3},{"source":"Fantine","target":"Blacheville","value":3},{"source":"Fantine","target":"Favourite","value":4},{"source":"Fantine","target":"Dahlia","value":4},{"source":"Fantine","target":"Zephine","value":4},{"source":"Fantine","target":"Marguerite","value":2},{"source":"Fantine","target":"Valjean","value":9},{"source":"Mme.Thenardier","target":"Fantine","value":2},{"source":"Mme.Thenardier","target":"Valjean","value":7},{"source":"Thenardier","target":"Mme.Thenardier","value":13},{"source":"Thenardier","target":"Fantine","value":1},{"source":"Thenardier","target":"Valjean","value":12},{"source":"Cosette","target":"Mme.Thenardier","value":4},{"source":"Cosette","target":"Valjean","value":31},{"source":"Cosette","target":"Tholomyes","value":1},{"source":"Cosette","target":"Thenardier","value":1},{"source":"Javert","target":"Valjean","value":17},{"source":"Javert","target":"Fantine","value":5},{"source":"Javert","target":"Thenardier","value":5},{"source":"Javert","target":"Mme.Thenardier","value":1},{"source":"Javert","target":"Cosette","value":1},{"source":"Fauchelevent","target":"Valjean","value":8},{"source":"Fauchelevent","target":"Javert","value":1},{"source":"Bamatabois","target":"Fantine","value":1},{"source":"Bamatabois","target":"Javert","value":1},{"source":"Bamatabois","target":"Valjean","value":2},{"source":"Perpetue","target":"Fantine","value":1},{"source":"Simplice","target":"Perpetue","value":2},{"source":"Simplice","target":"Valjean","value":3},{"source":"Simplice","target":"Fantine","value":2},{"source":"Simplice","target":"Javert","value":1},{"source":"Scaufflaire","target":"Valjean","value":1},{"source":"Woman1","target":"Valjean","value":2},{"source":"Woman1","target":"Javert","value":1},{"source":"Judge","target":"Valjean","value":3},{"source":"Judge","target":"Bamatabois","value":2},{"source":"Champmathieu","target":"Valjean","value":3},{"source":"Champmathieu","target":"Judge","value":3},{"source":"Champmathieu","target":"Bamatabois","value":2},{"source":"Brevet","target":"Judge","value":2},{"source":"Brevet","target":"Champmathieu","value":2},{"source":"Brevet","target":"Valjean","value":2},{"source":"Brevet","target":"Bamatabois","value":1},{"source":"Chenildieu","target":"Judge","value":2},{"source":"Chenildieu","target":"Champmathieu","value":2},{"source":"Chenildieu","target":"Brevet","value":2},{"source":"Chenildieu","target":"Valjean","value":2},{"source":"Chenildieu","target":"Bamatabois","value":1},{"source":"Cochepaille","target":"Judge","value":2},{"source":"Cochepaille","target":"Champmathieu","value":2},{"source":"Cochepaille","target":"Brevet","value":2},{"source":"Cochepaille","target":"Chenildieu","value":2},{"source":"Cochepaille","target":"Valjean","value":2},{"source":"Cochepaille","target":"Bamatabois","value":1},{"source":"Pontmercy","target":"Thenardier","value":1},{"source":"Boulatruelle","target":"Thenardier","value":1},{"source":"Eponine","target":"Mme.Thenardier","value":2},{"source":"Eponine","target":"Thenardier","value":3},{"source":"Anzelma","target":"Eponine","value":2},{"source":"Anzelma","target":"Thenardier","value":2},{"source":"Anzelma","target":"Mme.Thenardier","value":1},{"source":"Woman2","target":"Valjean","value":3},{"source":"Woman2","target":"Cosette","value":1},{"source":"Woman2","target":"Javert","value":1},{"source":"MotherInnocent","target":"Fauchelevent","value":3},{"source":"MotherInnocent","target":"Valjean","value":1},{"source":"Gribier","target":"Fauchelevent","value":2},{"source":"Mme.Burgon","target":"Jondrette","value":1},{"source":"Gavroche","target":"Mme.Burgon","value":2},{"source":"Gavroche","target":"Thenardier","value":1},{"source":"Gavroche","target":"Javert","value":1},{"source":"Gavroche","target":"Valjean","value":1},{"source":"Gillenormand","target":"Cosette","value":3},{"source":"Gillenormand","target":"Valjean","value":2},{"source":"Magnon","target":"Gillenormand","value":1},{"source":"Magnon","target":"Mme.Thenardier","value":1},{"source":"Mlle.Gillenormand","target":"Gillenormand","value":9},{"source":"Mlle.Gillenormand","target":"Cosette","value":2},{"source":"Mlle.Gillenormand","target":"Valjean","value":2},{"source":"Mme.Pontmercy","target":"Mlle.Gillenormand","value":1},{"source":"Mme.Pontmercy","target":"Pontmercy","value":1},{"source":"Mlle.Vaubois","target":"Mlle.Gillenormand","value":1},{"source":"Lt.Gillenormand","target":"Mlle.Gillenormand","value":2},{"source":"Lt.Gillenormand","target":"Gillenormand","value":1},{"source":"Lt.Gillenormand","target":"Cosette","value":1},{"source":"Marius","target":"Mlle.Gillenormand","value":6},{"source":"Marius","target":"Gillenormand","value":12},{"source":"Marius","target":"Pontmercy","value":1},{"source":"Marius","target":"Lt.Gillenormand","value":1},{"source":"Marius","target":"Cosette","value":21},{"source":"Marius","target":"Valjean","value":19},{"source":"Marius","target":"Tholomyes","value":1},{"source":"Marius","target":"Thenardier","value":2},{"source":"Marius","target":"Eponine","value":5},{"source":"Marius","target":"Gavroche","value":4},{"source":"BaronessT","target":"Gillenormand","value":1},{"source":"BaronessT","target":"Marius","value":1},{"source":"Mabeuf","target":"Marius","value":1},{"source":"Mabeuf","target":"Eponine","value":1},{"source":"Mabeuf","target":"Gavroche","value":1},{"source":"Enjolras","target":"Marius","value":7},{"source":"Enjolras","target":"Gavroche","value":7},{"source":"Enjolras","target":"Javert","value":6},{"source":"Enjolras","target":"Mabeuf","value":1},{"source":"Enjolras","target":"Valjean","value":4},{"source":"Combeferre","target":"Enjolras","value":15},{"source":"Combeferre","target":"Marius","value":5},{"source":"Combeferre","target":"Gavroche","value":6},{"source":"Combeferre","target":"Mabeuf","value":2},{"source":"Prouvaire","target":"Gavroche","value":1},{"source":"Prouvaire","target":"Enjolras","value":4},{"source":"Prouvaire","target":"Combeferre","value":2},{"source":"Feuilly","target":"Gavroche","value":2},{"source":"Feuilly","target":"Enjolras","value":6},{"source":"Feuilly","target":"Prouvaire","value":2},{"source":"Feuilly","target":"Combeferre","value":5},{"source":"Feuilly","target":"Mabeuf","value":1},{"source":"Feuilly","target":"Marius","value":1},{"source":"Courfeyrac","target":"Marius","value":9},{"source":"Courfeyrac","target":"Enjolras","value":17},{"source":"Courfeyrac","target":"Combeferre","value":13},{"source":"Courfeyrac","target":"Gavroche","value":7},{"source":"Courfeyrac","target":"Mabeuf","value":2},{"source":"Courfeyrac","target":"Eponine","value":1},{"source":"Courfeyrac","target":"Feuilly","value":6},{"source":"Courfeyrac","target":"Prouvaire","value":3},{"source":"Bahorel","target":"Combeferre","value":5},{"source":"Bahorel","target":"Gavroche","value":5},{"source":"Bahorel","target":"Courfeyrac","value":6},{"source":"Bahorel","target":"Mabeuf","value":2},{"source":"Bahorel","target":"Enjolras","value":4},{"source":"Bahorel","target":"Feuilly","value":3},{"source":"Bahorel","target":"Prouvaire","value":2},{"source":"Bahorel","target":"Marius","value":1},{"source":"Bossuet","target":"Marius","value":5},{"source":"Bossuet","target":"Courfeyrac","value":12},{"source":"Bossuet","target":"Gavroche","value":5},{"source":"Bossuet","target":"Bahorel","value":4},{"source":"Bossuet","target":"Enjolras","value":10},{"source":"Bossuet","target":"Feuilly","value":6},{"source":"Bossuet","target":"Prouvaire","value":2},{"source":"Bossuet","target":"Combeferre","value":9},{"source":"Bossuet","target":"Mabeuf","value":1},{"source":"Bossuet","target":"Valjean","value":1},{"source":"Joly","target":"Bahorel","value":5},{"source":"Joly","target":"Bossuet","value":7},{"source":"Joly","target":"Gavroche","value":3},{"source":"Joly","target":"Courfeyrac","value":5},{"source":"Joly","target":"Enjolras","value":5},{"source":"Joly","target":"Feuilly","value":5},{"source":"Joly","target":"Prouvaire","value":2},{"source":"Joly","target":"Combeferre","value":5},{"source":"Joly","target":"Mabeuf","value":1},{"source":"Joly","target":"Marius","value":2},{"source":"Grantaire","target":"Bossuet","value":3},{"source":"Grantaire","target":"Enjolras","value":3},{"source":"Grantaire","target":"Combeferre","value":1},{"source":"Grantaire","target":"Courfeyrac","value":2},{"source":"Grantaire","target":"Joly","value":2},{"source":"Grantaire","target":"Gavroche","value":1},{"source":"Grantaire","target":"Bahorel","value":1},{"source":"Grantaire","target":"Feuilly","value":1},{"source":"Grantaire","target":"Prouvaire","value":1},{"source":"MotherPlutarch","target":"Mabeuf","value":3},{"source":"Gueulemer","target":"Thenardier","value":5},{"source":"Gueulemer","target":"Valjean","value":1},{"source":"Gueulemer","target":"Mme.Thenardier","value":1},{"source":"Gueulemer","target":"Javert","value":1},{"source":"Gueulemer","target":"Gavroche","value":1},{"source":"Gueulemer","target":"Eponine","value":1},{"source":"Babet","target":"Thenardier","value":6},{"source":"Babet","target":"Gueulemer","value":6},{"source":"Babet","target":"Valjean","value":1},{"source":"Babet","target":"Mme.Thenardier","value":1},{"source":"Babet","target":"Javert","value":2},{"source":"Babet","target":"Gavroche","value":1},{"source":"Babet","target":"Eponine","value":1},{"source":"Claquesous","target":"Thenardier","value":4},{"source":"Claquesous","target":"Babet","value":4},{"source":"Claquesous","target":"Gueulemer","value":4},{"source":"Claquesous","target":"Valjean","value":1},{"source":"Claquesous","target":"Mme.Thenardier","value":1},{"source":"Claquesous","target":"Javert","value":1},{"source":"Claquesous","target":"Eponine","value":1},{"source":"Claquesous","target":"Enjolras","value":1},{"source":"Montparnasse","target":"Javert","value":1},{"source":"Montparnasse","target":"Babet","value":2},{"source":"Montparnasse","target":"Gueulemer","value":2},{"source":"Montparnasse","target":"Claquesous","value":2},{"source":"Montparnasse","target":"Valjean","value":1},{"source":"Montparnasse","target":"Gavroche","value":1},{"source":"Montparnasse","target":"Eponine","value":1},{"source":"Montparnasse","target":"Thenardier","value":1},{"source":"Toussaint","target":"Cosette","value":2},{"source":"Toussaint","target":"Javert","value":1},{"source":"Toussaint","target":"Valjean","value":1},{"source":"Child1","target":"Gavroche","value":2},{"source":"Child2","target":"Gavroche","value":2},{"source":"Child2","target":"Child1","value":3},{"source":"Brujon","target":"Babet","value":3},{"source":"Brujon","target":"Gueulemer","value":3},{"source":"Brujon","target":"Thenardier","value":3},{"source":"Brujon","target":"Gavroche","value":1},{"source":"Brujon","target":"Eponine","value":1},{"source":"Brujon","target":"Claquesous","value":1},{"source":"Brujon","target":"Montparnasse","value":1},{"source":"Mme.Hucheloup","target":"Bossuet","value":1},{"source":"Mme.Hucheloup","target":"Joly","value":1},{"source":"Mme.Hucheloup","target":"Grantaire","value":1},{"source":"Mme.Hucheloup","target":"Bahorel","value":1},{"source":"Mme.Hucheloup","target":"Courfeyrac","value":1},{"source":"Mme.Hucheloup","target":"Gavroche","value":1},{"source":"Mme.Hucheloup","target":"Enjolras","value":1}]};
  
  var link = g.append("g")
    .attr("class", "links")
    .selectAll("line")
    .data(graph.links)
    .enter().append("line")
    .attr("stroke-width", function(d) {
      return Math.sqrt(d.value);
    });

  var node = g.append("g")
    .attr("class", "nodes")
    .selectAll("circle")
    .data(graph.nodes)
    .enter().append("circle")
    .attr("r", 5)
    .attr("fill", function(d) {
      return color(d.group);
    })
    .call(d3.drag()
      .on("start", dragstarted)
      .on("drag", dragged)
      .on("end", dragended));

  node.append("title")
    .text(function(d) {
      return d.id;
    });

  simulation
    .nodes(graph.nodes)
    .on("tick", ticked);

  simulation.force("link")
    .links(graph.links);

  function ticked() {
    link
      .attr("x1", function(d) {
        return d.source.x;
      })
      .attr("y1", function(d) {
        return d.source.y;
      })
      .attr("x2", function(d) {
        return d.target.x;
      })
      .attr("y2", function(d) {
        return d.target.y;
      });

    node
      .attr("cx", function(d) {
        return d.x;
      })
      .attr("cy", function(d) {
        return d.y;
      });
  }

  function dragstarted(d) {
    if (!d3.event.active) simulation.alphaTarget(0.3).restart();
    d.fx = d.x;
    d.fy = d.y;
  }

  function dragged(d) {
    d.fx = d3.event.x;
    d.fy = d3.event.y;
  }

  function dragended(d) {
    if (!d3.event.active) simulation.alphaTarget(0);
    d.fx = null;
    d.fy = null;
  }

  function zoomed() {
    g.attr("transform", d3.event.transform);
    // Manually offsets the zoom to compensate for the initial position. Should get fixed asap or the position variables made global.
    //svg.attr("transform", "translate(" + (d3.event.transform.x + 400) + "," + (d3.event.transform.y + 325) + ")scale(" +  d3.event.transform.k + ")");
  }
</script>

这篇关于强制布局放大在拖动或zomming的第一个刻度重置的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！