canvas实现十二星座星空图

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我是靠谱客的博主眯眯眼戒指，最近开发中收集的这篇文章主要介绍canvas实现十二星座星空图，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

效果如下：

代码如下：

<!DOCTYPE html>
<html>
<head lang="en">
 <meta charset="UTF-8">
 <title>canvas星座</title>
 <style>
 * {
  margin: 0;
  padding: 0;
  }
 #box{
  margin:10px 0 0 10px;;
 }
 input{
  outline: none;
  font-size:16px;
 }
 p{
  margin-bottom: 10px
 }
 input[type=date]{
  height:36px;
  text-indent:10px;
 }
 input[type=button]{
  background:#3A92FF;
  color:white;
  border: none;
  height:40px;
  padding:0 10px;
  margin-left: -2px;
 }
 #canvas{
  margin-left:10px;
  background-color: #000;
  display: none;
 }
 </style>
</head>
<body>
<div id="box">
 <p>请选择您的出生日期</p>
 <input type="date" id="birth"><input type="button" id="btn" value="展示我的星空图">
</div>
　<canvas id="canvas" width="550" height="550">你的浏览器不支持canvas</canvas>
<script type="text/javascript">
 var box=document.getElementById('box');
 var birth=document.getElementById('birth');
 var btn=document.getElementById('btn');
 var canvas=document.getElementById("canvas");
 var ctx=canvas.getContext("2d");
 var g1,date,timer;
 ctx.font = "30px Courier New";
 /*星座位置*/
 var star={
 "白羊座":[
  [[0.30,0.78],[0.34,0.66],[0.28,0.48],[0.60,0.26],[0.65,0.20],[0.71,0.23],[0.70,0.32],[0.72,0.36]],
  [ [0,1,2,3,4,5],[3,6,7]]
 ],
 "天秤座":[
  [[0.16,0.67],[0.34,0.60],[0.60,0.27],[0.75,0.23],[0.84,0.47],[0.63,0.74],[0.51,0.78]],
  [[0,1,2,3,4,5,6]]
 ],
 "摩羯座":[
  [[0.78,0.21],[0.78,0.34],[0.75,0.45],[0.75,0.70],[0.69,0.78],[0.31,0.66],[0.22,0.49],[0.30,0.53],[0.53,0.54]],
  [[0,1,2,3,4,5,6,7,8,1]]
 ],
 "水瓶座":[
  [[0.45,0.21],[0.37,0.35],[0.27,0.51],[0.30,0.58],[0.29,0.64],[0.48,0.79],[0.51,0.71],[0.58,0.68],[0.73,0.74],[0.43,0.53],[0.53,0.47]],
  [[0,1,2,3,4,5,6,7,8],[2,9,10]]
 ],
 "双鱼座":[
  [[0.28,0.43],[0.28,0.53],[0.36,0.73],[0.43,0.78],[0.50,0.70],[0.53,0.62],[0.57,0.58],[0.63,0.43],[0.67,0.39],[0.74,0.39],[0.77,0.34],[0.72,0.30],[0.75,0.22],[0.23,0.50],[0.66,0.33]],
  [[0,1,2,3,4,5,6,7,8,9,10,11,12],[0,13,1],[8,14,11]]
 ],
 "金牛座":[
  [[0.29,0.21],[0.39,0.36],[0.50,0.51],[0.50,0.57],[0.61,0.63],[0.77,0.71],[0.79,0.79],[0.22,0.43],[0.39,0.57],[0.60,0.71],[0.67,0.76]],
  [[0,1,2,3,4,5,6],[7,8,3],[4,9,10]]
 ],
 "双子座":[
  [[0.18,0.37],[0.25,0.45],[0.35,0.55],[0.39,0.68],[0.49,0.77],[0.51,0.63],[0.57,0.78],[0.28,0.29],[0.42,0.32],[0.61,0.49],[0.72,0.60],[0.83,0.59],[0.69,0.75],[0.22,0.54],[0.35,0.43],[0.48,0.21]],
 [[0,1,2,3,4],[2,5,6],[7,8,9,10,11],[9,12],[13,1,14,8,15]]
 ],
 "巨蟹座":[
  [ [0.16,0.39],[0.27,0.36],[0.52,0.49],[0.57,0.65],[0.83,0.78],[0.44,0.21]],
  [[0,1,2,3,4],[2,5]]
 ],
 "狮子座":[
  [
  [0.16,0.75],[0.23,0.67],[0.39,0.77],[0.71,0.53],[0.64,0.39],[0.55,0.37],[0.47,0.27],[0.54,0.24],[0.60,0.27],[0.85,0.56]],
  [[0,1,2,3,4,5,6,7,8],[3,9]]
 ],
 "处女座":[
  [[0.16,0.59],[0.35,0.63],[0.44,0.70],[0.62,0.51],[0.77,0.46],[0.84,0.37],[0.60,0.42],[0.65,0.26],[0.34,0.75]],
  [[0,1,2,3,4,5],[3,6,7],[2,8]]
 ],
 "天蝎座":[
  [[0.17,0.50],[0.28,0.63],[0.19,0.70],[0.28,0.78],[0.41,0.77],[0.49,0.72],[0.57,0.55],[0.59,0.44],[0.69,0.31],[0.74,0.21],[0.82,0.29],[0.79,0.44],[0.73,0.50],[0.38,0.47]],
  [[0,1,2,3,4,5,6,7,8,9,10,11,12],[1,13],[8,11]]
 ],
 "射手座":[
  [[0.22, 0.66],[0.24,0.51],[0.45,0.40],[0.54,0.37],[0.59,0.43],[0.66,0.50],[0.63,0.60],[0.66,0.67],[0.74,0.53],[0.77,0.39],[0.49,0.47],[0.29,0.68],[0.30,0.78],[0.48,0.21],[0.52,0.27],[0.59,0.29]],
  [[0,1,2,3,4,5,6,7,8,9],[2,10,11,12],[10,4],[13,14,15,3],[14,3]]
 ]
 };
 /*根据出生日期获取星座信息*/
 function getStarSign(ts){
 var d=new Date(ts),sign=d.getMonth()*100+d.getDate();
 switch(true)
 {
  case sign<20:
  return "摩羯座";
  case sign<119:
  return "水瓶座";
  case sign<221:
  return "双鱼座";
  case sign<320:
  return "白羊座";
  case sign<421:
  return "金牛座";
  case sign<522:
  return "双子座";
  case sign<623:
  return "巨蟹座";
  case sign<723:
  return "狮子座";
  case sign<823:
  return "处女座";
  case sign<923:
  return "天秤座";
  case sign<1022:
  return "天蝎座";
  case sign<1122:
  return "射手座";
  default:
  return "摩羯座";
 }
 }
 /*绘制星座*/
 function constellation(ctx,ary,w,h){
 /*创建线条*/
 var points=ary[0], lines=ary[1];
 ctx.strokeStyle="#FFF";
 var len=lines.length,i,ii,line,point;
 ctx.beginPath();
 while(len--)
 {
  i=1;
  line=lines[len];
  ii=line.length;
  point=points[line[0]];
  ctx.moveTo(point[0]*w,point[1]*h);
  for(;i<ii;i++){
  point=points[line[i]];
  ctx.lineTo(point[0]*w,point[1]*h);
  }
 }
 ctx.stroke();
 /*创建小圆*/
 var cur;
 i=0;
 ii=points.length;
 for(;i<ii;i++){
  cur=points[i];
  new Circle(cur[0]*w,cur[1]*h).draw();//new出实例
 }
 }
 /*创建小圆的构造函数*/
 function Circle(x,y,r){
 this.x=x;
 this.y=y;
 this.r=r||Math.round(Math.random()*8+4);
 }
 Circle.prototype={
 draw:function(){
  ctx.beginPath();
  g1=ctx.createRadialGradient(this.x,this.y,Math.round(Math.random()*1+1),this.x,this.y,Math.round(Math.random()*3+6));
  g1.addColorStop(0,'rgba(255,255,255,.9)');
  g1.addColorStop(1,'rgba(0,0,0,.1)');
  ctx.arc(this.x,this.y,this.r,0,Math.PI*2,true);
  ctx.fillStyle =g1;
  ctx.closePath();
  ctx.fill();
  return this;
 }};
 /*点击‘展示我的星空图'按钮*/
 btn.onclick=function(e){
 clearInterval(timer);
 e.preventDefault();
 if (!birth.value){
  alert("请选择您的出生日期");
 }else{
  canvas.style.display="block";
  date = new Date(birth.value.replace(/-/g,'/')).getTime();
  timer=setInterval(function(){
  ctx.clearRect(0,0,canvas.width,canvas.height);
  ctx.strokeText(getStarSign(date), 50, 50);
  constellation(ctx,star[getStarSign(date)],canvas.width,canvas.height);
  },500);
 }
 };
</script>
</body>
</html>

以上就是本文的全部内容，希望本文的内容对大家的学习或者工作能带来一定的帮助，同时也希望多多支持脚本之家！