canvas实现十二星座星空图

 

请选择您的出生日期

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 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*/

 varpoints=ary[0],lines=ary[1];

 ctx.strokeStyle="#FFF";

 varlen=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

  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

  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=newDate(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);

 }

 };