带边界框的 D3 力导向布局 [英] D3 force directed layout with bounding box

问题描述

我是 D3 的新手，无法为我的强制定向布局设置边界.我已经设法(从示例中)拼凑出我想要的东西，但我需要包含图形.在刻度函数中，转换/翻译将正确显示我的图形，但是当我将 cx 和 cy 与 Math.max/min 一起使用时(请参阅注释代码)，节点被固定到当线条被正确包含时左上角.

I am new to D3 and having trouble setting the bounds for my force directed layout. I have managed to piece together (from examples) what I would like, but I need the graph to be contained. In the tick function, a transform/translate will display my graph correctly, but when i use cx and cy with Math.max/min (See commented code), the nodes are pinned to the top left corner while the lines are contained properly.

这是我下面的内容......我做错了什么??

Here is what I have below... what am I doing wrong??

var w=960, h=500, r=8,  z = d3.scale.category20();

var color = d3.scale.category20();

var force = d3.layout.force()
       .linkDistance( function(d) { return (d.value*180) } )
       .linkStrength( function(d) { return (1/(1+d.value)) } )
       .charge(-1000)
       //.gravity(.08)
       .size([w, h]);

var vis = d3.select("#chart").append("svg:svg")
       .attr("width", w)
       .attr("height", h)
       .append("svg:g")
       .attr("transform", "translate(" + w / 4 + "," + h / 3 + ")");

vis.append("svg:rect")
   .attr("width", w)
   .attr("height", h)
   .style("stroke", "#000");


d3.json("miserables.json", function(json) {

       var link = vis.selectAll("line.link")
               .data(json.links);

       link.enter().append("svg:line")
               .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.source.x; })
               .attr("y2", function(d) { return d.source.y; })
               .style("stroke-width", function(d) { return (1/(1+d.value))*5 });

       var node = vis.selectAll("g.node")
               .data(json.nodes);

       var nodeEnter = node.enter().append("svg:g")
               .attr("class", "node")
               .on("mouseover", fade(.1))
               .on("mouseout", fade(1))
               .call(force.drag);

       nodeEnter.append("svg:circle")
               .attr("r", r)
               .style("fill", function(d) { return z(d.group); })
               .style("stroke", function(d) { return
d3.rgb(z(d.group)).darker(); });

       nodeEnter.append("svg:text")
               .attr("text-anchor", "middle")
               .attr("dy", ".35em")
               .text(function(d) { return d.name; });

       force
       .nodes(json.nodes)
       .links(json.links)
       .on("tick", tick)
       .start();

       function tick() {

       // This works
               node.attr("transform", function(d) { return "translate(" + d.x + ","
+ d.y + ")"; });

       // This contains the lines within the boundary, but the nodes are
stuck in the top left corner
               //node.attr("cx", function(d) { return d.x = Math.max(r, Math.min(w
- r, d.x)); })
               //      .attr("cy", function(d) { return d.y = Math.max(r, Math.min(h -
r, d.y)); });

       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; });
       }

       var linkedByIndex = {};

   json.links.forEach(function(d) {
       linkedByIndex[d.source.index + "," + d.target.index] = 1;
   });

       function isConnected(a, b) {
       return linkedByIndex[a.index + "," + b.index] ||
linkedByIndex[b.index + "," + a.index] || a.index == b.index;
   }

       function fade(opacity) {
       return function(d) {
           node.style("stroke-opacity", function(o) {
                       thisOpacity = isConnected(d, o) ? 1 : opacity;
                       this.setAttribute('fill-opacity', thisOpacity);
               return thisOpacity;
                       });

                       link.style("stroke-opacity", opacity).style("stroke-opacity",
function(o) {
               return o.source === d || o.target === d ? 1 : opacity;
               });
       };
       }

});

推荐答案

有一个 边界框示例 在我的关于力布局的讨论中.位置 Verlet 集成允许您在内部定义几何约束(例如边界框和 碰撞检测)滴答"事件侦听器；只需移动节点以符合约束条件，模拟就会相应地进行调整.

There's a bounding box example in my talk on force layouts. The position Verlet integration allows you to define geometric constraints (such as bounding boxes and collision detection) inside the "tick" event listener; simply move the nodes to comply with the constraint and the simulation will adapt accordingly.

也就是说，重力绝对是处理这个问题的更灵活的方法，因为它允许用户暂时将图形拖到边界框外，然后图形就会恢复.根据图表的大小和显示区域的大小，您应该尝试使用不同的重力和电荷(排斥力)相对强度，以使您的图表适合.

That said, gravity is definitely a more flexible way to deal with this problem, since it allows users to drag the graph outside the bounding box temporarily and then the graph will recover. Depend on the size of the graph and the size of the displayed area, you should experiment with different relative strengths of gravity and charge (repulsion) to get your graph to fit.

这篇关于带边界框的 D3 力导向布局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！