本节源码，拿走不谢。

(function(){
            function Vector(x,y){
                this.x = x || 0;
                this.y = y || 0;
            }
            Vector.prototype = {
                constructor:Vector,
                square:function(){
                    return this.x * this.x + this.y * this.y; 
                },
                length:function(){
                    return Math.sqrt(this.square()); 
                },
                add:function(q){
                    return new Vector(this.x + q.x,this.y+q.y); 
                },
                minus:function(q){
                    return new Vector(this.x - q.x,this.y-q.y);  
                },
                multipy:function(scale){
                    return new Vector(this.x*scale,this.y*scale);  
                },
                normalize:function(length){
                    if(length === undefined){
                        length = 1;
                    }
                    return this.multipy(length / this.length());
                }
            };
            Vector.fromPoints = function(p1,p2){
                return new Vector(p2.x - p1.x, p2.y - p1.y);
            };
            window.Vector = Vector;
        })();

慕移动7441361

2019-04-25

源自：走进SVG 7-1

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慕移动7441361 提问者
2019-04-25

sss

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慕移动7441361 提问者
2019-04-25

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>svg动画</title>
    <style>
        html,body,svg{
            margin:0;
            padding:0;
            width: 100%;
            height:100%;
        }
    </style>
</head>
<body>
    <svg 
        width="10000" 
        height="1000"
        viewBox="-400 -400 800 800"
    >
        <path 
            id="links"
            stroke="gray"
            fill="none"
        ></path>
    </svg>
    
    <script src="vector.js"></script>
    <script>
        var points = 'a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z'.split(',').map(function(name,index,arr){
            return {
                name:name,
                color:'hsl('+ (360*index/arr.length) + ',100%,60%)'
            };
        });
        var relation = 300;
        var svg = document.querySelector('svg');
        var k = 0.05;
        var Vector = window.Vector;
        function random(min,max){
            return Math.round(min +(max - min) *Math.random());
        };
        points.forEach(function(point){
            var circle = document.createElementNS('http://www.w3.org/2000/svg','circle');
            var x = random(-400,400);
            var y = random(-400,400);
            circle.setAttribute('cx',x);
            circle.setAttribute('cy',y);
            circle.setAttribute('r',10);
            circle.setAttribute('fill',point.color);
            svg.appendChild(circle);
            point.circle = circle;
            point.s = new Vector(x,y);
            point.v = new Vector();
            point.a = new Vector();
        });
        var lastFrameTime = +new Date();
        function update(){
            var frameTime = +new Date();
            var t = frameTime - lastFrameTime;
            t/=200;
            //点位置更新
            points.forEach(function(pa){
                var f = new Vector();
                //计算合力
                points.forEach(function(pb){
                    if(pa == pb) return;
                    var x = Vector.fromPoints(pa.s,pb.s);
                    var delta = x.length() -relation;
                    //f = k * x
                    f = f.add(x.normalize(delta * k));
                });
                pa.a = f;
                pa.v = pa.v.add(pa.a.multipy(t)).multipy(0.98);
                pa.s = pa.s.add(pa.v.multipy(t));
                pa.circle.setAttribute('cx',pa.s.x);
                pa.circle.setAttribute('cy',pa.s.y);
            });
            //连线更新
            var linkPath = [];
            points.forEach(function(pa){
                var sa = pa.s;
                points.forEach(function(pb){
                    if(pa == pb) return;
                    var sb = pb.s;
                    linkPath = linkPath.concat([
                        'M',sa.x,sa.y,
                        'L',sb.x,sb.y
                    ]);
                });
            });
            document.getElementById('links').setAttribute('d',linkPath.join(' '))
            lastFrameTime = frameTime;
            window.requestAnimationFrame(update);
        };
        window.requestAnimationFrame(update);
    </script>
</body>
</html>

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