前端代码在线执行—

<!DOCTYPE html>
<html>
<head>
    <title>SVG path 画线 - 迹忆客(jiyik.com)</title>
    <meta charset="utf-8">
    <style>
        .links {
            stroke: #000;
            stroke-opacity: 0.2;
        }

.polygons {
            fill: none;
            stroke: #000;
        }

.polygons :first-child {
            fill: #f00;
        }

.sites {
            fill: #000;
            stroke: #fff;
        }

.sites :first-child {
            fill: #fff;
        }  </style>
</head>
<body>
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
    var svg = d3.select("svg").on("touchmove mousemove", moved), width = +svg.attr("width"),
        height = +svg.attr("height");
    var sites = d3.range(100).map(function (d) {
        return [Math.random() * width, Math.random() * height];
    });
    var voronoi = d3.voronoi().extent([[-1, -1], [width + 1, height + 1]]);
    var polygon = svg.append("g").attr("class", "polygons").selectAll("path").data(voronoi.polygons(sites)).enter().append("path").call(redrawPolygon);
    var link = svg.append("g").attr("class", "links").selectAll("line").data(voronoi.links(sites)).enter().append("line").call(redrawLink);
    var site = svg.append("g").attr("class", "sites").selectAll("circle").data(sites).enter().append("circle").attr("r", 2.5).call(redrawSite);

function moved() {
        sites[0] = d3.mouse(this);
        redraw();
    }

function redraw() {
        var diagram = voronoi(sites);
        polygon = polygon.data(diagram.polygons()).call(redrawPolygon);
        link = link.data(diagram.links()), link.exit().remove();
        link = link.enter().append("line").merge(link).call(redrawLink);
        site = site.data(sites).call(redrawSite);
    }

function redrawPolygon(polygon) {
        polygon.attr("d", function (d) {
            return d ? "M" + d.join("L") + "Z" : null;
        });
    }

function redrawSite(site) {
        site.attr("cx", function (d) {
            return d[0];
        }).attr("cy", function (d) {
            return d[1];
        });
    }
</script>
</body>
</html>