javascript – d3.js – 强制布局边界问题V4

目前我在FCC的项目National Contiguity工作

本质上我能够弄清楚如何渲染标志精灵并连接节点及其链接.

我唯一遇到的问题是实现的是如何表现得与FCC的example类似.具体来说,我正在尝试让节点像示例中那样排斥边界.

但是,我的行为并不那样(事实上,它是非常集群的,但我不确切知道d3.js Force Documents V4中我应该研究哪些属性).相反,似乎虽然节点和链接在边界附近停止,但它在那个点停止

const width = w - (margin.left + margin.right);
const height = h - (margin.top + margin.bottom);

let flagNodes = d3.select("#canvas")
                  .append("div")
                  .classed("flag-nodes",true)


let svg = d3.select("#canvas")
              .append("svg")
              .attr("id","chart")
              .attr("width", w)
              .attr("height", h)


let chart = svg.append("g")
                .classed("display", true)
                .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

let simulation = d3.forceSimulation()
    .force("link", d3.forceLink().id(function(d,i) {
      return i;
    }))
    .force("charge", d3.forceManyBody().strength(-60).distanceMax(50).distanceMin(5))
    .force("center", d3.forceCenter(width/2, height/2))
    .force("collide", d3.forceCollide().radius(35))
    // .force("centering", d3.forceCenter(,height))
    // .force("position", d3.forceX(0).strength(.01))
    // .force("position", d3.forceY(-18))


let link = chart.append("g")
        .classed("links",true)
        .selectAll("line")
        .data(data.links)
        .enter()
          .append("line")

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

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

let node = flagNodes.selectAll(".flag-nodes")
        .data(data.nodes)
        .enter()
          .append("div")
          .attr("class", function(d,i){
            return `flag flag-${d.code}`
          })
          .call(d3.drag()
          .on("start", dragstarted)
          .on("drag", dragged)
          .on("end", dragended)
        )

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

d3.forceX(width)

//functions provided by D3.js
//
function ticked() {
    node
        .style("left", function(d) {
          let xlimit = Math.max(radius, Math.min(width - radius, d.x))
          return (xlimit) + 'px'
        })
        .style("top", function(d) {
          let ylimit = Math.max(radius, Math.min(height - radius, d.y))
          return (ylimit - 2) + 'px'
        });
    link
        .attr("x1", function(d) {
          let x1 = Math.max(radius, Math.min(width - radius, d.source.x))
          return x1;
        })
        .attr("y1", function(d) {
          let y1 = Math.max(radius, Math.min(height - radius, d.source.y))
          return y1
        })
        .attr("x2", function(d) {
          let x2 = Math.max(radius, Math.min(width - radius, d.target.x))
          return x2;
        })
        .attr("y2", function(d) {
          let y2 = Math.max(radius, Math.min(height - radius, d.target.y))
          return y2
        });
  }

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;
}

Codepen

解决方法:

在每个tick上,在模拟节点上运行此函数：

fixBounds() {
    const graphNodes = this.forceSimulation.nodes();

    graphNodes.forEach((node) => {
        if (node.x - this.nodeRadius < 0) {
            node.x = this.nodeRadius;
            node.vx = 0;
        }

        if (node.y - this.nodeRadius < 0) {
            node.y = this.nodeRadius;
            node.vy = 0;
        }

        if (this.width && node.x + this.nodeRadius > this.width) {
            node.x = this.width - this.nodeRadius;
            node.vx = 0;
        }

        if (this.height && node.y + this.nodeRadius > this.height) {
            node.y = this.height - this.nodeRadius;
            node.yx = 0;
        }
    })
} 

这将导致节点卡在边界上,节点之间的力将使它们远离边界.

标签：javascript,d3-js,force-layout
来源： https://codeday.me/bug/20190706/1393701.html