如何在悬停时显示D3节点的文本

Question

我对D3非常陌生，我正在尝试复制文本的行为，就像用鼠标悬停、鼠标输出行为来完成这里的圆圈元素一样。基本上，悬停时显示文本，不悬停时隐藏文本。我是否需要创建一个节点var，就像我用圆圈和文本创建的那样，或者用当前的实现：是否可能

var nodes = {};
// Compute the distinct nodes from the links.
links.forEach(function(link) {
link.source = nodes[link.source] || (nodes[link.source] = {name: link.source, value: link.type});
link.target = nodes[link.target] || (nodes[link.target] = {name: link.target, value: link.type});
});
var width = 1000,
height = 900;
var force = d3.layout.force()
.nodes(d3.values(nodes))
.links(links)
.size([width, height])
.linkDistance(90)
.charge(-125)
.on("tick", tick)
.start();
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
// Per-type markers, as they don't inherit styles.
svg.append("defs").selectAll("marker")
.data(["suit", "licensing", "resolved"])
.enter().append("marker")
.attr("id", function(d) { return d; })
.attr("viewBox", "0 -5 10 10")
.attr("refX", 15)
.attr("refY", -1.5)
.attr("markerWidth", 6)
.attr("markerHeight", 6)
.attr("orient", "auto")
.append("path")
.attr("d", "M0,-5L10,0L0,5");
var path = svg.append("g").selectAll("path")
.data(force.links())
.enter().append("path")
.attr("class", function(d) { return "link " + d.type; })
.attr("marker-end", function(d) { return "url(#" + d.type + ")"; })
.style("stroke", function(d){ 
if (d.type >= 0.4) {
return '#000066'
}
if (d.type >= 0.25) {
return '#ccccff'
}
if (d.type >= 0.01) {
return 'e8f4f8'
}
else {
return '#FFFFFF'
}
});  
var circle = svg.append("g").selectAll("circle")
.data(force.nodes())
.enter().append("circle")
.attr("r", 6)
.on("dblclick", dblclick)
.on('mouseover', function(d){
var nodeSelection = d3.select(this).style({opacity:'0.5'});
nodeSelection.select("text").style({opacity:'1.0'});
})
.on('mouseout', function(d){
var nodeSelection = d3.select(this).style({opacity:'0.0'});
nodeSelection.select("text").style({opacity:'0.0'});
})
.call(force.drag);
var text = svg.append("g").selectAll("text")
.data(force.nodes())
.enter().append("text")
.attr("x", 8)
.attr("y", ".31em")
.text(function(d){ 
if (d.value >= 0.35){
return d.name
}
});
// Use elliptical arc path segments to doubly-encode directionality.
function tick() {
path.attr("d", linkArc);
circle.attr("transform", transform);
text.attr("transform", transform);
}
function linkArc(d) {
var dx = d.target.x - d.source.x,
dy = d.target.y - d.source.y,
dr = Math.sqrt(dx * dx + dy * dy);
return "M" + d.source.x + "," + d.source.y + "A" + dr + "," + dr + " 0 0,1 " + d.target.x + "," + d.target.y;
}
function transform(d) {
return "translate(" + d.x + "," + d.y + ")";
}
var drag = force.drag()
.on("dragstart", dragstart);
function dblclick(d) {
d3.select(this).classed("fixed", d.fixed = false);
}
function dragstart(d) {
d3.select(this).classed("fixed", d.fixed = true);
}

Answer 1

为默认为0的文本添加不透明度属性。您似乎已经有文本要在mouseover/mouseout上显示和隐藏。如果你的方法对你不起作用，我也发布了一种不同的方法。

var text = svg.append("g").selectAll("text")
.data(force.nodes())
.enter().append("text")
.attr("x", 8)
.attr("y", ".31em")
.attr("opacity", 1)
.text(function(d){ 
if (d.value >= 0.35){
return d.name
}
});

function mouseout(d) {  text.style("opacity",  0); }
function mouseover(d) { text.style("opacity", 1);