js canvas实现简单的图像扩散效果

时间:2020-05-16 wangbo54979 人气:0

本文实例为大家分享了canvas实现简单图像扩散的代码，供大家参考，具体内容如下

<!DOCTYPE HTML> 
<html> 
<body> 
 
<canvas id="myCanvas" width="800" height="800" style="border:1px solid #c3c3c3;"> 
Your browser does not support the canvas element. 
</canvas> 
 
<script type="text/javascript"> 
 
var c=document.getElementById("myCanvas"); 
var cxt=c.getContext("2d"); 
var x1=200,x2=400,x3=600,y1=400,y2=400,y3=400,lr1=10,lr2=10,lr3=10; 
var lc1="#EE7942";lc2="#EE2C2C";lc3="#CD6839"; 
var lr1,lr2,lr3; 
 
 
drawarc(15,"#CAE1FF",1); 
drawarc(25,"#98FB98",2); 
drawarc(25,"#757575",3); 
 
drawarc(30,"#000000",1); 
drawarc(35,"#32CD32",2); 
drawarc(50,"#6959CD",3); 
 
 
drawarc(45,"red",1); 
drawarc(50,"#fff",2); 
drawarc(65,"#000",3); 
 
 
function drawarc(radiu,ecolor,type){ 
  var grd; 
  var x,y,r; 
  var scolor; 
   switch(type){ 
    case 1: 
     x=x1; 
     y=y1; 
     r=lr1; 
     lr1=radiu; 
     scolor=lc1; 
    break; 
    case 2: 
     x=x2; 
     y=y2; 
     r=lr2; 
     lr2=radiu; 
     scolor=lc2; 
    break; 
    case 3: 
     x=x3; 
     y=y3; 
     r=lr3; 
     lr3=radiu; 
     scolor=lc3; 
     break; 
    default: 
   } 
  grd=cxt.createRadialGradient(x,y,r,x,y,radiu); 
  grd.addColorStop(0,scolor); 
  grd.addColorStop(1,ecolor); 
  cxt.fillStyle=grd; 
  cxt.beginPath(); 
  cxt.arc(x,y,radiu,0,360,false); 
  cxt.closePath(); 
  cxt.fill(); 
} 
</script> 
 
</body> 
</html>

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