Canvas实现动态粒子连线效果（附代码）

朱雀 2020-06-29 14:34 1023阅读 0赞

# Canvas实现动态粒子连线效果（附代码）

**JS+Canvas制作动画，实现动态粒子连线效果**

**效果图如下**
![](/images/1593441244326.gif)

**思路如下：**

- 绘制随机区域的粒子，记录每个粒子x轴、y轴坐标以及x轴与y轴每次移动的距离
- 通过定时函数使得粒子进行移动，移动后判断是否超过界限，超过则将该粒子删除并生成一个新的粒子
- 判断所有粒子之间的距离，对给定距离的粒子进行连线。

**代码如下：**

```html
<!DOCTYPE html>
<html>
 <head>
 <meta charset="UTF-8">
 <title>Canvas动态粒子连线</title>
 </head>
   
 <body>
 <canvas id="myCanvas" style="border: 1px solid #ddd; display: block;margin: 20px auto;"></canvas>
 <script>
 var myCanvas = document.getElementById("myCanvas");
 myCanvas.width = "800";
 myCanvas.height = "800";
 var cxt = myCanvas.getContext("2d");
 cxt.fillStyle="#ddd";
 var points =new Array();
 //绘制60个粒子
 for(var i=0;i<60;i++)
 {
 drawlizi();
 }
 setInterval(movelizi,100);
   
 //绘制静态粒子
 function drawlizi(){
 var x = generate_random(3,797);
 var y = generate_random(3,797);
 var speedx = generate_random(-4,4);
 var speedy = generate_random(-4,4);
 //防止出现不移动的粒子
 while(speedx==0&&speedy==0)
 {
 speedx = generate_random(-4,4);
 speedy = generate_random(-4,4);
 }
 var point={
 x_index:x,
 y_index:y,
 x_speed:speedx,
 y_speed:speedy
 };
 points.push(point);
 cxt.beginPath();
 cxt.arc(x,y,3,0,360);
 cxt.closePath();
 cxt.fill();
 }
   
 //粒子移动
 function movelizi(){
 cxt.clearRect(0, 0,myCanvas.width,myCanvas.height);
 for(var i=0;i<points.length;i++)
 {
 points[i].x_index = points[i].x_index+points[i].x_speed;
 points[i].y_index = points[i].y_index+points[i].y_speed;
 cxt.beginPath();
 cxt.arc(points[i].x_index,points[i].y_index,3,0,360);
 cxt.closePath();
 cxt.fill();
 //判断超过界限删除并再生
 if((points[i].x_index<3||points[i].y_index<3)||(points[i].x_index>797||points[i].y_index<3)||(points[i].x_index<3||points[i].y_index>797)||(points[i].x_index>797||points[i].y_index>797)){
 points.splice(i,1);
 drawlizi();
 }
 }
 //相近的粒子进行连线
 for (var i=0;i<points.length;i++) {
 for (var j=0;j<points.length;j++) {
 if(i!=j)
 {
 var one_x = points[i].x_index;
 var one_y = points[i].y_index;
 var two_x = points[j].x_index;
 var two_y = points[j].y_index;
 // 根据两点间的距离公式，小于界限值便进行连线
 var jl = Math.sqrt(Math.pow(one_x-two_x,2)+Math.pow(one_y-two_y,2));
 if(jl<100)
 {
 cxt.strokeStyle="#ddd";
 cxt.moveTo(one_x,one_y);
 cxt.lineTo(two_x,two_y);
 cxt.stroke();
 }
 }
 }
 }
 }
 //生成两个数之间的随机数
 function generate_random(min,max){
 return Math.floor(Math.random()*(max-min)+min);
 } 
 </script>
 </body>
   
</html>
```