javascript - D3 强制布局颜色和缩放

Question

我正在使用以下代码片段，并尝试纠正链接行为的一些错误。

预期行为如下:

• 默认情况下，链接根据链接的“类型”(“A”或“E”)着色
• 将鼠标悬停在节点上时，该节点及其直接邻居保持完全不透明度和颜色，但其余节点和链接会降低不透明度，并且链接颜色会变为白色。
• 鼠标移开时，节点和链接将恢复其原始的不透明度和颜色
• 缩放时，节点和链接都会相应缩放。

不幸的是，我的代码不满足最后三个要点，并且在此过程中的某个地方，链接现在呈现在节点顶部，而不是相反。

谁能帮我指出我哪里出错了？

Codepen - https://codepen.io/quirkules/pen/BOKRjY

//create somewhere to put the force directed graph
var height = 650,
    width = 950;

var svg = d3.select("body").append("svg")
            .attr('width',width)
            .attr('height',height);

var radius = 15; 

var nodes_data =  [
    {"name": "Lillian", "sex": "F"},
    {"name": "Gordon", "sex": "M"},
    {"name": "Sylvester", "sex": "M"},
    {"name": "Mary", "sex": "F"},
    {"name": "Helen", "sex": "F"},
    {"name": "Jamie", "sex": "M"},
    {"name": "Jessie", "sex": "F"},
    {"name": "Ashton", "sex": "M"},
    {"name": "Duncan", "sex": "M"},
    {"name": "Evette", "sex": "F"},
    {"name": "Mauer", "sex": "M"},
    {"name": "Fray", "sex": "F"},
    {"name": "Duke", "sex": "M"},
    {"name": "Baron", "sex": "M"},
    {"name": "Infante", "sex": "M"},
    {"name": "Percy", "sex": "M"},
    {"name": "Cynthia", "sex": "F"},
    {"name": "Feyton", "sex": "M"},
    {"name": "Lesley", "sex": "F"},
    {"name": "Yvette", "sex": "F"},
    {"name": "Maria", "sex": "F"},
    {"name": "Lexy", "sex": "F"},
    {"name": "Peter", "sex": "M"},
    {"name": "Ashley", "sex": "F"},
    {"name": "Finkler", "sex": "M"},
    {"name": "Damo", "sex": "M"},
    {"name": "Imogen", "sex": "F"}
    ]

//Sample links data 
//type: A for Ally, E for Enemy
var links_data = [
    {"source": "Sylvester", "target": "Gordon", "type":"A" },
    {"source": "Sylvester", "target": "Lillian", "type":"A" },
    {"source": "Sylvester", "target": "Mary", "type":"A"},
    {"source": "Sylvester", "target": "Jamie", "type":"A"},
    {"source": "Sylvester", "target": "Jessie", "type":"A"},
    {"source": "Sylvester", "target": "Helen", "type":"A"},
    {"source": "Helen", "target": "Gordon", "type":"A"},
    {"source": "Mary", "target": "Lillian", "type":"A"},
    {"source": "Ashton", "target": "Mary", "type":"A"},
    {"source": "Duncan", "target": "Jamie", "type":"A"},
    {"source": "Gordon", "target": "Jessie", "type":"A"},
    {"source": "Sylvester", "target": "Fray", "type":"E"},
    {"source": "Fray", "target": "Mauer", "type":"A"},
    {"source": "Fray", "target": "Cynthia", "type":"A"},
    {"source": "Fray", "target": "Percy", "type":"A"},
    {"source": "Percy", "target": "Cynthia", "type":"A"},
    {"source": "Infante", "target": "Duke", "type":"A"},
    {"source": "Duke", "target": "Gordon", "type":"A"},
    {"source": "Duke", "target": "Sylvester", "type":"A"},
    {"source": "Baron", "target": "Duke", "type":"A"},
    {"source": "Baron", "target": "Sylvester", "type":"E"},
    {"source": "Evette", "target": "Sylvester", "type":"E"},
    {"source": "Cynthia", "target": "Sylvester", "type":"E"},
    {"source": "Cynthia", "target": "Jamie", "type":"E"},
    {"source": "Mauer", "target": "Jessie", "type":"E"},
    {"source": "Duke", "target": "Lexy", "type":"A"},
    {"source": "Feyton", "target": "Lexy", "type":"A"},
    {"source": "Maria", "target": "Feyton", "type":"A"},
    {"source": "Baron", "target": "Yvette", "type":"E"},
    {"source": "Evette", "target": "Maria", "type":"E"},
    {"source": "Cynthia", "target": "Yvette", "type":"E"},
    {"source": "Maria", "target": "Jamie", "type":"E"},
    {"source": "Maria", "target": "Lesley", "type":"E"},
    {"source": "Ashley", "target": "Damo", "type":"A"},
    {"source": "Damo", "target": "Lexy", "type":"A"},
    {"source": "Maria", "target": "Feyton", "type":"A"},
    {"source": "Finkler", "target": "Ashley", "type":"E"},
    {"source": "Sylvester", "target": "Maria", "type":"E"},
    {"source": "Peter", "target": "Finkler", "type":"E"},
    {"source": "Ashley", "target": "Gordon", "type":"E"},
    {"source": "Maria", "target": "Imogen", "type":"E"}

]


//set up the simulation and add forces  
var simulation = d3.forceSimulation()
                    .nodes(nodes_data);

var link_force =  d3.forceLink(links_data)
                        .id(function(d) { return d.name; });            

var charge_force = d3.forceManyBody()
    .strength(-100); 

var center_force = d3.forceCenter(width / 2, height / 2);  

simulation
    .force("charge_force", charge_force)
    .force("center_force", center_force)
    .force("link",link_force)
 ;


//add tick instructions: 
simulation.on("tick", tickActions );

//add encompassing group for the zoom 
var g = svg.append("g")
    .attr("class", "everything");

//draw circles for the nodes 
var node = g.append("g")
        .attr("class", "nodes") 
        .selectAll("circle")
        .data(nodes_data)
        .enter()
        .append("circle")
        .attr("r", radius)
        .attr("fill", circleColour)
        .on("mouseover", mouseOver(.1))
        .on("mouseout", mouseOut); 

// add the curved links to our graphic
var link = svg.selectAll(".link")
    .data(links_data)
    .enter()
    .append("path")
    .attr("class", "link")
    .style('stroke', linkColour)
    .attr('stroke-width', 2);    

//add drag capabilities  
var drag_handler = d3.drag()
    .on("start", drag_start)
    .on("drag", drag_drag)
    .on("end", drag_end);   

drag_handler(node);


//add zoom capabilities 
var zoom_handler = d3.zoom()
    .on("zoom", zoom_actions);

zoom_handler(svg);     

/** Functions **/

//Function to choose what color circle we have
//Let's return blue for males and red for females
function circleColour(d){
    if(d.sex =="M"){
        return "blue";
    } else {
        return "pink";
    }
}

//Function to choose the line colour and thickness 
//If the link type is "A" return green 
//If the link type is "E" return red 
function linkColour(d){
    if(d.type == "A"){
        return "green";
    } else {
        return "red";
    }
}

//Drag functions 
//d is the node 
function drag_start(d) {
 if (!d3.event.active) simulation.alphaTarget(0.3).restart();
    d.fx = d.x;
    d.fy = d.y;
}

//make sure you can't drag the circle outside the box
function drag_drag(d) {
  d.fx = d3.event.x;
  d.fy = d3.event.y;
}

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

//Zoom functions 
function zoom_actions(){
    g.attr("transform", d3.event.transform)
}

function tickActions() {
    //update circle positions each tick of the simulation 
       node
        .attr("cx", function(d) { return d.x; })
        .attr("cy", function(d) { return d.y; });

    //update link positions 
    link.attr("d", positionLink);
} 

// links are drawn as curved paths between nodes,
// through the intermediate nodes
function positionLink(d) {
    var offset = 30;

    var midpoint_x = (d.source.x + d.target.x) / 2;
    var midpoint_y = (d.source.y + d.target.y) / 2;

    var dx = (d.target.x - d.source.x);
    var dy = (d.target.y - d.source.y);

    var normalise = Math.sqrt((dx * dx) + (dy * dy));

    var offSetX = midpoint_x + offset * (dy / normalise);
    var offSetY = midpoint_y - offset * (dx / normalise);

    return "M" + d.source.x + "," + d.source.y +
        "S" + offSetX + "," + offSetY +
        " " + d.target.x + "," + d.target.y;
}

// links are drawn as curved paths between nodes,
// through the intermediate nodes
function positionLink(d) {
    var offset = 30;

    var midpoint_x = (d.source.x + d.target.x) / 2;
    var midpoint_y = (d.source.y + d.target.y) / 2;

    var dx = (d.target.x - d.source.x);
    var dy = (d.target.y - d.source.y);

    var normalise = Math.sqrt((dx * dx) + (dy * dy));

    var offSetX = midpoint_x + offset * (dy / normalise);
    var offSetY = midpoint_y - offset * (dx / normalise);

    return "M" + d.source.x + "," + d.source.y +
        "S" + offSetX + "," + offSetY +
        " " + d.target.x + "," + d.target.y;
}

// build a dictionary of nodes that are linked
var linkedByIndex = {};
links_data.forEach(function(d) {
    linkedByIndex[d.source.index + "," + d.target.index] = 1;
});

// check the dictionary to see if nodes are linked
function isConnected(a, b) {
    return linkedByIndex[a.index + "," + b.index] || linkedByIndex[b.index + "," + a.index] || a.index == b.index;
}

// fade nodes on hover
function mouseOver(opacity) {
    return function(d) {
        // check all other nodes to see if they're connected
        // to this one. if so, keep the opacity at 1, otherwise
        // fade
        node.style("stroke-opacity", function(o) {
            thisOpacity = isConnected(d, o) ? 1 : opacity;
            return thisOpacity;
        });
        node.style("fill-opacity", function(o) {
            thisOpacity = isConnected(d, o) ? 1 : opacity;
            return thisOpacity;
        });
        // also style link accordingly
        link.style("stroke-opacity", function(o) {
            return o.source === d || o.target === d ? 1 : opacity;
        });
        link.style("stroke", function(o) {
            return o.source === d || o.target === d ? o.source.colour : "#ddd";
        });
    };
}

function mouseOut() {
    node.style("stroke-opacity", 1);
    node.style("fill-opacity", 1);
    link.style("stroke-opacity", 1);
    link.style("stroke", "#ddd");
}

Answer 1

看起来您在第 #116 行有一个简单的拼写错误:

// add the curved links to our graphic
var link = svg.selectAll(".link")
    .data(links_data)
    .enter()
    .append("path")
    .attr("class", "link")
    .style('stroke', linkColour)
    .attr('stroke-width', 2);

此代码将所有链接放置在根 <svg> 下元素，而不是组。如果您更改 svg.selectAll(...)至g.selectAll(...) ，看起来工作正常。