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我试图同时在一个页面上放置多个 D3 强制布局。理想情况下,力布局的数量是可变的,具体取决于从动态 API 返回的根数。我已经按照关于多个力布局的这个问题的答案,并成功地将每个布局放在一个单独的 div 中,在一个单独的 svg 中。

然而,问题是双重的:

1) svgs 似乎是同时绘制的,导致 alpha 冷却参数发生冲突(在每个图表的“tick”上)。因此,唯一按照预期方式定位的布局是页面上绘制的最后一个 svg。tick 函数包含的代码将力布局塑造成类似于垂柳树,根节点位于顶部,子节点位于其下方。

2) 设置循环以迭代 API 的完整结果列表会导致 D3 崩溃,并出现错误“Uncaught TypeError: Cannot read property 'textContent' of null”。

我认为理想的解决方案是在成功渲染前一个力布局后绘制每个力布局,以一种不会导致 alpha 冷却参数(在“tick”上)发生冲突或使 D3 库因过多实例而过载的方式一下子的兵力布局。有人对这个问题有洞察力吗?这是我的代码:

/* ... GET THE RESULTS FROM THE API ...*/
function handleRequest2(json) {
        allroots = json[1]['data']['children'];
        (function() {
            var index = 0;
            function LoopThrough() {
                currentRoot = allroots[index];  
                if (index < allroots.length) {
                    /* DRAW THE GRAPH */
                    draw_graphs(currentRoot, index);  
                    ++index;
                    LoopThrough();
                    };
            }

        LoopThrough();
        })(); 

    }
//Force Layout Code
function draw_graphs(root, id) {
var root_id = "map-" + id.toString();
var force;
var vis;
var link;
var node;
var w = 980;
var h = 1000;
var k = 0;
// Create a separate div to house each SVG graph
  div = document.createElement("div");
  div.style.width = "980px";
  div.style.height = "1000px";
  div.style.cssFloat="left";
  div.id = root_id;
  $(div).addClass("chattermap-map");
  // Append the div to the chart container
  $('#chart').append(div);

force = d3.layout.force()
  .size([w, h])
  .charge(-250)
  .gravity(0)
  .on("tick", tick);
  // Create the SVG and append it to the created div
vis = d3.select("#"+root_id)
  .append("svg:svg")
  .attr("width", w)
  .attr("height", h)
  .attr("id",root_id);


  // Put the Reddit JSON in the correct format for the Force Layout
nodes = flatten(root),
links = optimize(d3.layout.tree().links(nodes));
// Calculations for the sizing of the nodes
avgNetPositive = getAvgNetPositive();
maxNetPositive = d3.max(netPositiveArray);
minNetPositive = d3.min(netPositiveArray);
// Create a logarithmic scale that sizes the nodes
radius = d3.scale.pow().exponent(.3).domain([minNetPositive,maxNetPositive]).range([5,30]);
// Fix the root node to the top of the svg
root.data.fixed = true;
root.data.x = w/2;
root.data.y = 50;
  // Start the force layout.
force
  .nodes(nodes)
  .links(links)
  .start();
  // Update the links
  link = vis.selectAll("line.link")
    .data(links, function(d) { return d.target.id; });
  // Enter any new links.
  link.enter().insert("svg:line", ".node")
    .attr("class", "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; });
  // Exit any old links.
  link.exit().remove();
  // Update the nodes
  node = vis.selectAll("circle.node")
    .data(nodes, function(d) {return d.id; })
    .style("fill", function(d) {
      return '#2960b5';
    });
    // Enter any new nodes.
  node.enter().append("svg:circle")
    .attr("class", "node")
    .attr("cx", function(d) {return d.x; })
    .attr("cy", function(d) {return d.y; })
    .attr("r", function(d) {
        //Get the net positive reaction
        var netPositive = d.ups - d.downs;
        var relativePositivity = netPositive/avgNetPositive;
        //Scale the radii based on the logarithmic scale defined earlier
        return radius(netPositive);
    })
    .style("fill", function(d) {
      return '#2960b5';
    })
    // Allow dragging on click
    .call(force.drag);
    // Exit any old nodes.
  node.exit().remove();
  //This will add the name of the author to the node HTML
  node.append("author").text(function(d) {return d.author});
  //Add the body of the comment to the node
  node.append("comment").text(function(d) {return Encoder.htmlDecode(d.body_html)}); 
  //Add the UNIX timestamp to the node
  node.append("timestamp").text(function(d) {return moment.unix(d.created_utc).fromNow();})
  //On load, assign the root node to the tooltip
  numberOfNodes = node[0].length;
  rootNode = d3.select(node[0][parseInt(numberOfNodes) - 1]);
  rootNodeComment = rootNode.select("comment").text();
  rootNodeAuthor = rootNode.select("author").text();
  rootNodeTimestamp = rootNode.select("timestamp").text();

  // Create the tooltip div for the comments
tooltip_div = d3.select("#"+root_id).append("div")
    .attr("class", "tooltip")               
      .style("opacity", 1);
//Add the HTML to the tooltip for the root
  tooltip_div .html("<span class='commentAuthor'>" + rootNodeAuthor + "</span><span class='bulletTimeAgo'>&bull;</span><span class='timestamp'>" + rootNodeTimestamp + "</span><br>" + rootNodeComment)
    //Position the tooltip based on the position of the current node, and it's size
    .style("left", (rootNode.attr("cx") - (-rootNode.attr("r")) - (-9)) + "px")   
    .style("top", (rootNode.attr("cy") - 15)  + "px");    

  node.on("mouseover", function() {
    currentNode = d3.select(this);
    currentTitle = currentNode.select("comment").text();
    currentAuthor = currentNode.select("author").text();
    currentTimestamp = currentNode.select("timestamp").text();
  tooltip_div.transition()        
     .duration(200)      
     .style("opacity", 1);
  // Add the HTML for all other tooltips on mouseover
  tooltip_div .html("<span class='commentAuthor'>" + currentAuthor + "</span><span class='bulletTimeAgo'>&bull;</span><span class='timestamp'>" + currentTimestamp + "</span><br>" + currentTitle)
              //Position the tooltip based on the position of the current node, and it's size
              .style("left", (currentNode.attr("cx") - (-currentNode.attr("r")) - (-9)) + "px")   
              .style("top", (currentNode.attr("cy") - 15)  + "px");    
   });

  // Fade out the tooltip on mouseout
  node.on("mouseout", function(d) {       
      tooltip_div.transition()        
          .duration(500)      
          .style("opacity", 1);
  });
  // Optimize the JSON output of Reddit for D3
  function flatten(root) {

    var nodes = [], i = 0, j = 0;
    function recurse(node) {

      if (node['data']['replies'] != "" && node['kind'] != "more") {
          node['data']['replies']['data']['children'].forEach(recurse);
      }
      if (node['kind'] !="more") {
          //Add an ID value to the node starting at 1
          node.data.id = ++i;
          node.data.name = node.data.body;
          //Put the replies in the key 'children' to work with the tree layout
          if (node.data.replies != "") {

               node.data.children = node.data.replies.data.children;
               //Remove the extra 'data' layer for each child
               for (j=0; j < node.data.children.length; j++) {
                  node.data.children[j] = node.data.children[j].data;
               }

          } else {
              node.data.children = "";
          }
          var comment = node.data;
          nodes.push(comment);
      }
    }
    recurse(root);
    return nodes;  
  }
  // Optimize the JSON for use with Links
  function optimize(linkArray) {
      optimizedArray = [];
      for (k=0; k < linkArray.length; k++) {
          if(typeof linkArray[k].target.count == 'undefined') {
              optimizedArray.push(linkArray[k]);
          }
      }
      return optimizedArray;
  }
  // Get the average net positive upvotes for use in sizing
  function getAvgNetPositive() {
    var sum = 0;
    netPositiveArray = []
    //Select all the nodes
    var allNodes = d3.selectAll(nodes)[0];
    //For each node, get the net positive votes and add it to the sum
    for (i=0; i < allNodes.length; i++) {
      var netPositiveEach = allNodes[i]["ups"] - allNodes[i]["downs"];
      sum += netPositiveEach;
      netPositiveArray.push(netPositiveEach);
    }
    var avgNetPositive = sum/allNodes.length;
    return avgNetPositive;
  }
  function tick(e) {
     var kx = .4 * e.alpha, ky = 1.4 * e.alpha;
     links.forEach(function(d, i) {
        d.target.x += (d.source.x - d.target.x) * kx;
        d.target.y += (d.source.y + 80 - d.target.y) * ky;
    });
    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; });
  }
  // // Remove the animation effect of the force layout
  // while ((force.alpha() > 1e-2) && (k < 150)) {
  //     force.tick(),
  //     k = k + 1;
  // }
}

提前致谢!

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1 回答 1

1

如果您将它们封装在它们自己的命名空间中,例如通过单独的函数,您应该能够使多个力布局同时工作。但是,您也可以通过收听事件来做您想做的end事情——请参阅文档。这样,您可以“链接”布局,在前一个完成后开始每个布局。

关于另一个错误,这似乎是由不完整/错误的数据引起的。

于 2013-10-14T08:22:28.557 回答