当鼠标悬停时，我尝试更改链接和箭头颜色连接到特定节点。
问题是无法找到如何捕捉相应的箭头（但我可以选择链接，请参阅我的代码末尾）以改变颜色
这是我的实际代码。如果有人可以提供帮助，那就太棒了
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<style type="text/css">
.node { font: 12px sans-serif;}
.link { stroke: black; stroke-opacity: .4; stroke-width: 2px; }
</style>
</head>
<body>
<svg width="1500" height="1000"></svg>
<script src="http://d3js.org/d3.v4.min.js" type="text/javascript"></script>
<script src="http://d3js.org/d3-selection-multi.v1.js"></script>
<script type="text/javascript">
var colors = d3.scaleOrdinal(d3.schemeCategory20);
var svg = d3.select("svg"),
width = +svg.attr("width"),
height = +svg.attr("height"),
node,
link;
svg.append('defs').append('marker')
.attrs({'id':'arrowhead',
'viewBox':'-0 -5 10 10',
'refX':15,
'refY':0,
'orient':'auto',
'markerWidth':6,
'markerHeight':6,
'xoverflow':'visible'})
.append('svg:path')
.attr('d', 'M 0,-5 L 10 ,0 L 0,5')
.style('fill', 'black')
.style('stroke', 'black');
var simulation = d3.forceSimulation()
.force("link", d3.forceLink().id(function (d) {return d.id;}).distance(500).strength(1))
.force("charge", d3.forceManyBody())
.force("center", d3.forceCenter(width / 2, height / 2));
var jsonstring = '{"nodes": [{"name": "25", "id": "25"},{"name": "16", "id": "16"},{"name": "12", "id": "12"},{"name": "20", "id": "20"},{"name": "21", "id": "21"},{"name": "9", "id": "9"},{"name": "24", "id": "24"},{"name": "5", "id": "5"},{"name": "23", "id": "23"},{"name": "13", "id": "13"},{"name": "14", "id": "14"},{"name": "15", "id": "15"},{"name": "18", "id": "18"},{"name": "2", "id": "2"},{"name": "3", "id": "3"},{"name": "4", "id": "4"},{"name": "6", "id": "6"},{"name": "7", "id": "7"},{"name": "10", "id": "10"},{"name": "11", "id": "11"},{"name": "1", "id": "1"},{"name": "22", "id": "22"},{"name": "17", "id": "17"},{"name": "19", "id": "19"},{"name": "8", "id": "8"}],"links": [{"source": "25", "target": "16"},{"source": "25", "target": "12"},{"source": "25", "target": "20"},{"source": "25", "target": "21"},{"source": "25", "target": "9"},{"source": "25", "target": "24"},{"source": "25", "target": "12"},{"source": "16", "target": "16"},{"source": "16", "target": "12"},{"source": "16", "target": "12"},{"source": "12", "target": "16"},{"source": "12", "target": "12"},{"source": "12", "target": "5"},{"source": "12", "target": "12"},{"source": "20", "target": "16"},{"source": "20", "target": "12"},{"source": "20", "target": "23"},{"source": "20", "target": "13"},{"source": "20", "target": "14"},{"source": "20", "target": "5"},{"source": "20", "target": "15"},{"source": "20", "target": "12"},{"source": "21", "target": "16"},{"source": "21", "target": "12"},{"source": "21", "target": "15"},{"source": "21", "target": "13"},{"source": "21", "target": "18"},{"source": "21", "target": "2"},{"source": "21", "target": "12"},{"source": "9", "target": "16"},{"source": "9", "target": "12"},{"source": "9", "target": "23"},{"source": "9", "target": "21"},{"source": "9", "target": "13"},{"source": "9", "target": "3"},{"source": "9", "target": "12"},{"source": "24", "target": "16"},{"source": "24", "target": "12"},{"source": "24", "target": "23"},{"source": "24", "target": "18"},{"source": "24", "target": "4"},{"source": "24", "target": "6"},{"source": "24", "target": "7"},{"source": "24", "target": "12"},{"source": "5", "target": "16"},{"source": "5", "target": "12"},{"source": "5", "target": "12"},{"source": "5", "target": "4"},{"source": "5", "target": "15"},{"source": "5", "target": "10"},{"source": "5", "target": "12"},{"source": "23", "target": "16"},{"source": "23", "target": "12"},{"source": "23", "target": "6"},{"source": "23", "target": "10"},{"source": "23", "target": "12"},{"source": "13", "target": "16"},{"source": "13", "target": "12"},{"source": "13", "target": "20"},{"source": "13", "target": "10"},{"source": "13", "target": "14"},{"source": "13", "target": "5"},{"source": "13", "target": "11"},{"source": "13", "target": "1"},{"source": "13", "target": "16"},{"source": "13", "target": "12"},{"source": "14", "target": "16"},{"source": "14", "target": "12"},{"source": "14", "target": "2"},{"source": "14", "target": "13"},{"source": "14", "target": "4"},{"source": "14", "target": "5"},{"source": "14", "target": "12"},{"source": "15", "target": "16"},{"source": "15", "target": "12"},{"source": "15", "target": "6"},{"source": "15", "target": "10"},{"source": "15", "target": "22"},{"source": "15", "target": "20"},{"source": "15", "target": "12"},{"source": "18", "target": "16"},{"source": "18", "target": "12"},{"source": "18", "target": "2"},{"source": "18", "target": "12"},{"source": "2", "target": "16"},{"source": "2", "target": "12"},{"source": "2", "target": "13"},{"source": "2", "target": "17"},{"source": "2", "target": "12"},{"source": "2", "target": "11"},{"source": "2", "target": "12"},{"source": "3", "target": "16"},{"source": "3", "target": "12"},{"source": "3", "target": "16"},{"source": "3", "target": "18"},{"source": "3", "target": "10"},{"source": "3", "target": "12"},{"source": "4", "target": "16"},{"source": "4", "target": "12"},{"source": "4", "target": "14"},{"source": "4", "target": "5"},{"source": "4", "target": "13"},{"source": "4", "target": "10"},{"source": "4", "target": "12"},{"source": "4", "target": "12"},{"source": "6", "target": "16"},{"source": "6", "target": "12"},{"source": "6", "target": "20"},{"source": "6", "target": "13"},{"source": "6", "target": "3"},{"source": "6", "target": "19"},{"source": "6", "target": "12"},{"source": "7", "target": "16"},{"source": "7", "target": "12"},{"source": "7", "target": "20"},{"source": "7", "target": "21"},{"source": "7", "target": "12"},{"source": "7", "target": "8"},{"source": "7", "target": "9"},{"source": "7", "target": "11"},{"source": "7", "target": "12"},{"source": "10", "target": "16"},{"source": "10", "target": "12"},{"source": "10", "target": "1"},{"source": "10", "target": "5"},{"source": "10", "target": "17"},{"source": "10", "target": "22"},{"source": "10", "target": "16"},{"source": "10", "target": "4"},{"source": "10", "target": "13"},{"source": "10", "target": "12"},{"source": "11", "target": "16"},{"source": "11", "target": "12"},{"source": "11", "target": "7"},{"source": "11", "target": "3"},{"source": "11", "target": "12"},{"source": "11", "target": "22"},{"source": "11", "target": "12"},{"source": "1", "target": "16"},{"source": "1", "target": "12"},{"source": "1", "target": "16"},{"source": "1", "target": "22"},{"source": "1", "target": "9"},{"source": "1", "target": "15"},{"source": "1", "target": "12"},{"source": "22", "target": "16"},{"source": "22", "target": "12"},{"source": "22", "target": "5"},{"source": "22", "target": "2"},{"source": "22", "target": "17"},{"source": "22", "target": "12"},{"source": "22", "target": "8"},{"source": "22", "target": "12"},{"source": "19", "target": "16"},{"source": "19", "target": "12"},{"source": "19", "target": "24"},{"source": "19", "target": "15"},{"source": "19", "target": "16"},{"source": "19", "target": "23"},{"source": "19", "target": "12"},{"source": "8", "target": "16"},{"source": "8", "target": "12"},{"source": "8", "target": "20"},{"source": "8", "target": "15"},{"source": "8", "target": "12"},{"source": "8", "target": "12"}]}';
var graph=JSON.parse(jsonstring);
//d3.json("graph.json", function (error, graph) {
//if (error) throw error;
update(graph.links, graph.nodes);
//})
function update(links, nodes) {
link = svg.selectAll(".link")
.data(links)
.enter()
.append("line")
.attr("class", "link")
.attr('marker-end','url(#arrowhead)')
link.append("title")
.text(function (d) {return d.type;});
edgepaths = svg.selectAll(".edgepath")
.data(links)
.enter()
.append('path')
.attrs({
'class': 'edgepath',
'fill-opacity': 0,
'stroke-opacity': 0,
'id': function (d, i) {return 'edgepath' + i}
})
.style("pointer-events", "none");
edgelabels = svg.selectAll(".edgelabel")
.data(links)
.enter()
.append('text')
.style("pointer-events", "none")
.attrs({
'class': 'edgelabel',
'id': function (d, i) {return 'edgelabel' + i},
'font-size': 10,
'fill': '#aaa'
});
edgelabels.append('textPath')
.attr('xlink:href', function (d, i) {return '#edgepath' + i})
.style("text-anchor", "middle")
.style("pointer-events", "none")
.attr("startOffset", "50%")
.text(function (d) {return d.type});
node = svg.selectAll(".node")
.data(nodes)
.enter()
.append("g")
.attr("class", "node")
.call(d3.drag()
.on("start", dragstarted)
.on("drag", dragged)
//.on("end", dragended)
);
node.append("circle")
.attr("r", 8)
.style("fill", function (d, i) {return colors(i);})
node.append("title")
.text(function (d) {return d.id;});
node.append("text")
.attr("dy", -4)
.attr("dx", 10)
.text(function (d) {return d.name;});
simulation
.nodes(nodes)
.on("tick", ticked);
simulation.force("link")
.links(links);
}
function ticked() {
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("transform", function (d) {return "translate(" + d.x + ", " + d.y + ")";});
edgepaths.attr('d', function (d) {
return 'M ' + d.source.x + ' ' + d.source.y + ' L ' + d.target.x + ' ' + d.target.y;
});
edgelabels.attr('transform', function (d) {
if (d.target.x < d.source.x) {
var bbox = this.getBBox();
rx = bbox.x + bbox.width / 2;
ry = bbox.y + bbox.height / 2;
return 'rotate(180 ' + rx + ' ' + ry + ')';
}
else {
return 'rotate(0)';
}
});
}
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;
}
// On node hover, examine the links to see if their
// source or target properties match the hovered node.
node.on('mouseover', function(d) {
link.style('stroke', function(l) {
if (d === l.source || d === l.target)
return "red";
else
return "black";
});
});
// Set the stroke width back to normal when mouse leaves the node.
node.on('mouseout', function() {
link.style('stroke', "black");
});
// function dragended(d) {
// if (!d3.event.active) simulation.alphaTarget(0);
// d.fx = undefined;
// d.fy = undefined;
// }
</script>
</body>
</html>