本文实例为大家分享了js canvas星空连线背景的具体代码，供大家参考，具体内容如下
<html> <head> <Meta charset="UTF-8"> <title>canvas星空连线背景特效</title> <style type="text/css"> body{ margin: 0; } #canvas{ display: block; background: #000; margin: 0 auto; } </style> </head> <body> <canvas id="canvas"></canvas> <script> function Starry(){ this.cxt=canvas.getContext("2d"); canvas.width=window.innerWidth; canvas.height=window.innerHeight; this.cW=canvas.width; this.cH=canvas.height; this.num=200; this.data=[]; } Starry.prototype={ init: function(){ for (var i=0;i<this.num;i++) { this.data[i]={ x:Math.random()*this.cW,y:Math.random()*this.cH,cX:Math.random()*0.6-0.3,cY:Math.random()*0.6-0.3 }; this.drawCircle(this.data[i].x,this.data[i].y); } },drawCircle: function(x,y){ var cxt=canvas.getContext("2d"); cxt.save();//保存路径 cxt.fillStyle="pink"; cxt.beginPath();//开始路径 cxt.arc(x,y,1,Math.PI*2,false); cxt.closePath();//结束路径 cxt.fill();//填充方法 cxt.restore();//释放路径 },drawLine: function(x1,y1,x2,y2){ var cxt=this.cxt; var color=cxt.createLinearGradient(x1,y2); color.addColorStop(0,"yellow"); color.addColorStop(1,"green"); cxt.save(); cxt.strokeStyle=color; cxt.beginPath();//开始路径 cxt.moveTo(x1,y1); cxt.lineTo(x2,y2); cxt.closePath();//结束路径 cxt.stroke();//填充方法 cxt.restore();//释放路径 },moveCircle: function(){ var self=this; self.cxt.clearRect(0,self.cW,self.cH); for(var i=0;i<self.num;i++){ self.data[i].x+=self.data[i].cX; self.data[i].y+=self.data[i].cY; if(self.data[i].x>self.cW||self.data[i].x<0){ self.data[i].cX=-self.data[i].cX; } if(self.data[i].x>self.cH||self.data[i].y<0){ self.data[i].cY=-self.data[i].cY; } this.drawCircle(self.data[i].x,self.data[i].y); for(var j=i+1;j<self.num;j++){ if(Math.pow(self.data[i].x-self.data[j].x,2) +Math.pow(self.data[i].y-self.data[j].y,2) <=50*50){ self.drawLine(self.data[i].x,self.data[i].y,self.data[j].x,self.data[j].y); } } } } } var starry=new Starry(); starry.init(); setInterval(function(){starry.moveCircle();},1); </script> </body> </html>
