canvas二进制字符下落

 
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>二进制雨</title>
</head>
<body align="center">

<h2>二进制雨</h2>

<-- 宽高原先是1000*600 js忘了改-->
<canvas id="myCanvas" width="480px" height="320px" style="background-color: black;"></canvas>

<script>

var draw=function(ctx,x,y,size){
this.ctx=ctx;
this.x=x;
this.y=y;
this.size=size;
var y1=this.y;
this.drawText=function(){
var str=Math.ceil(Math.random()*10000).toString(2);
var grd=this.ctx.createLinearGradient(this.x,this.y,this.x,this.y-this.ctx.measureText(str).width);
grd.addColorStop(0,"#00FF00");
grd.addColorStop(1,"#004400");
this.ctx.fillStyle=grd;
this.ctx.font=this.size+"px Arial";
for(var i=str.length-1;i>=0;i--) {
this.ctx.fillText(str.charAt(i), this.x, y1-=15);
}
y1=this.y+=10;
if(y1-720+this.ctx.measureText(str).width>0){
this.x=Math.ceil(Math.random()*1000);
y1=this.y=Math.ceil(Math.random()*100);
}
}
};

var rain=function(ctx,length){
this.length=length;
this.ctx=ctx;
var x=[];
var y=[];
var size=[];
var texts=[];
var i=0;
for(;i<length;i++){
x[i]=Math.ceil(Math.random()*1000);
y[i]=Math.ceil(Math.random()*500);
size[i]=Math.ceil(Math.random()*15);
texts[i]=new draw(this.ctx,x[i],y[i],size[i]);
}
this.run=function(){
ctx.clearRect(0,0,1000,600);
for(var j=0;j<length;j++){
texts[j].drawText();
}
};

};

var canvas=document.getElementById("myCanvas");
var ctx=canvas.getContext("2d");
var rain0=new rain(ctx,100);
setInterval(rain0.run,50);

</script>
</body>
</html>

    

 

当时是初学 并没有对代码优化,所以看看就好. 

 

canvas二进制雨  | 菜鸟工具
预览https://c.runoob.com/codedemo/3301

 

 

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原文地址：https://www.cnblogs.com/startnow/p/5013383.html