javascript HTML5 Canvas melaksanakan kemahiran function_javascript loteri cakera-tutorial js-php.cn

Kami sering menyertai pelbagai aktiviti keutamaan e-dagang, seperti aktiviti loteri apabila pembelian mencapai jumlah tertentu, seperti loteri WeChat, loteri Taobao, loteri cakera Xunlei Money Making, dsb. Aktiviti loteri ini sebahagiannya dihasilkan oleh HTML5 Canvas Hari ini saya akan berkongsi dengan anda cara menggunakan HTML5 Canvas untuk mencipta fungsi loteri cakera. Seperti biasa, mari kita lihat pemaparan dahulu:
Mari kita lihat beberapa API utama Kanvas:
Kod sumber penuh adalah seperti berikut:
<!DOCTYPE html>
<html lang="zh-cn">
<head>
<meta charset="UTF-8">
<title>HTML5 Canvas圆盘抽奖应用DEMO演示</title>
<meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
<style>
*{padding: 0px;margin: 0px;font-size: 16px;font-family: "Microsoft YaHei";}
.xttblog_box{width: 300px;height: 300px;margin: 100px auto;position: relative; }
.xttblog_box canvas{position: absolute;}
#xttblog{background-color: white;border-radius: 100%;}
#xttblog01,#xttblog03{left: 50px;top: 50px;z-index: 30;}
#xttblog02{left: 75px;top: 75px;z-index: 20;}
#xttblog{-o-transform: transform 6s;-ms-transform: transform 6s;-moz-transform: transform 6s;  
-webkit-transform: transform 6s;transition: transform 6s;-o-transform-origin: 50% 50%;
-ms-transform-origin: 50% 50%;-moz-transform-origin: 50% 50%;-webkit-transform-origin: 50% 50%;
transform-origin: 50% 50%;}
.taoge_btn{width: 60px;height: 60px;left: 120px;top: 120px;border-radius: 100%;
position: absolute;cursor: pointer;border: none;background: transparent;
outline: none;z-index: 40;}
</style>
<script type="text/javascript" src="http://cdn.bootcss.com/jquery/1.11.3/jquery.min.js"></script>
<script>
$(document).ready(function(){
 //旋转角度
 var angles;
 //可抽奖次数
 var clickNum = 5;
 //旋转次数
 var rotNum = 0;
 //中奖公告
 var notice = null;
 //转盘初始化
 var color = ["#626262","#787878","rgba(0,0,0,0.5)","#DCC722","white","#FF4350"];
 var info = ["谢谢参与"," 1000"," 10"," 500"," 100"," 4999"," 1"," 20"];
 var info1 = ['再接再厉','  元','  元',' 淘金币','  元',' 淘金币','  元',' 淘金币']
 canvasRun();
 $('#tupBtn').bind('click',function(){
  if (clickNum >= 1) {
   //可抽奖次数减一
   clickNum = clickNum-1;
   //转盘旋转
   runCup();
   //转盘旋转过程“开始抽奖”按钮无法点击
   $('#tupBtn').attr("disabled", true);
   //旋转次数加一
   rotNum = rotNum + 1;
   //“开始抽奖”按钮无法点击恢复点击
   setTimeout(function(){
    alert(notice);
    $('#tupBtn').removeAttr("disabled", true);
   },6000);
  }
  else{
   alert("亲，抽奖次数已用光！");
  }
 });
 
 //转盘旋转
 function runCup(){
  probability();
  var degValue = 'rotate('+angles+'deg'+')';
  $('#xttblog').css('-o-transform',degValue);   //Opera
  $('#xttblog').css('-ms-transform',degValue);   //IE浏览器
  $('#xttblog').css('-moz-transform',degValue);   //Firefox
  $('#xttblog').css('-webkit-transform',degValue);  //Chrome和Safari
  $('#xttblog').css('transform',degValue);
 }
 
 //各奖项对应的旋转角度及中奖公告内容
 function probability(){
  //获取随机数
  var num = parseInt(Math.random()*(7 - 0 + 0) + 0);
  //概率
  if ( num == 0 ) {
   angles = 2160 * rotNum + 1800;
   notice = info[0] + info1[0];
  }
  //概率
  else if ( num == 1 ) {
   angles = 2160 * rotNum + 1845;
   notice = info[7] + info1[7];
  }
  //概率
  else if ( num == 2 ) {
   angles = 2160 * rotNum + 1890;
   notice = info[6] + info1[6];
  }
  //概率
  else if ( num == 3 ) {
   angles = 2160 * rotNum + 1935;
   notice = info[5] + info1[5];
  }
  //概率
  else if ( num == 4 ) {
   angles = 2160 * rotNum + 1980;
   notice = info[4] + info1[4];
  }
  //概率
  else if ( num == 5 ) {
   angles = 2160 * rotNum + 2025;
   notice = info[3] + info1[3];
  }
  //概率
  else if ( num == 6 ) {
   angles = 2160 * rotNum + 2070;
   notice = info[2] + info1[2];
  }
  //概率
  else if ( num == 7 ) {
   angles = 2160 * rotNum + 2115;
   notice = info[1] + info1[1];
  }
 }
 
 //绘制转盘
 function canvasRun(){
  var canvas=document.getElementById('xttblog');
  var canvas01=document.getElementById('xttblog01');
  var canvas03=document.getElementById('xttblog03');
  var canvas02=document.getElementById('xttblog02');
  var ctx=canvas.getContext('2d');
  var ctx1=canvas01.getContext('2d');
  var ctx3=canvas03.getContext('2d');
  var ctx2=canvas02.getContext('2d');
  createCircle();
  createCirText();
  initPoint();
  
  //外圆
  function createCircle(){
   var startAngle = 0;//扇形的开始弧度
   var endAngle = 0;//扇形的终止弧度
   //画一个8等份扇形组成的圆形
   for (var i = 0; i< 8; i++){
    startAngle = Math.PI*(i/4-1/8);
    endAngle = startAngle+Math.PI*(1/4);
    ctx.save();
    ctx.beginPath();
    ctx.arc(150,150,100, startAngle, endAngle, false);
    ctx.lineWidth = 120;
    if (i%2 == 0) {
     ctx.strokeStyle = color[0];
    }else{
     ctx.strokeStyle = color[1];
    }
    ctx.stroke();
    ctx.restore();
   }
  }
 
  //各奖项
  function createCirText(){ 
   ctx.textAlign='start';
   ctx.textBaseline='middle';
   ctx.fillStyle = color[3];
   var step = 2*Math.PI/8;
   for ( var i = 0; i < 8; i++) {
    ctx.save();
    ctx.beginPath();
    ctx.translate(150,150);
    ctx.rotate(i*step);
    ctx.font = " 20px Microsoft YaHei";
    ctx.fillStyle = color[3];
    ctx.fillText(info[i],-30,-115,60);
    ctx.font = " 14px Microsoft YaHei";
    ctx.fillText(info1[i],-30,-95,60);
    ctx.closePath();
    ctx.restore();
   }
  }
 
  function initPoint(){
   //箭头指针
   ctx1.beginPath();
   ctx1.moveTo(100,24);
   ctx1.lineTo(90,62);
   ctx1.lineTo(110,62);
   ctx1.lineTo(100,24);
   ctx1.fillStyle = color[5];
   ctx1.fill();
   ctx1.closePath();
   //中间小圆
   ctx3.beginPath();
   ctx3.arc(100,100,40,0,Math.PI*2,false);
   ctx3.fillStyle = color[5];
   ctx3.fill();
   ctx3.closePath();
   //小圆文字
   ctx3.font = "Bold 20px Microsoft YaHei";
   ctx3.textAlign='start';
   ctx3.textBaseline='middle';
   ctx3.fillStyle = color[4];
   ctx3.beginPath();
   ctx3.fillText('开始',80,90,40);
   ctx3.fillText('抽奖',80,110,40);
   ctx3.fill();
   ctx3.closePath();
   //中间圆圈
   ctx2.beginPath();
   ctx2.arc(75,75,75,0,Math.PI*2,false);
   ctx2.fillStyle = color[2];
   ctx2.fill();
   ctx2.closePath();
  }
 }
});
</script>
</head>
<body>
<div class="xttblog_box">
 <canvas id="xttblog" width="300px" height="300px">抱歉！浏览器不支持。</canvas>
 <canvas id="xttblog01" width="200px" height="200px">抱歉！浏览器不支持。</canvas>
 <canvas id="xttblog03" width="200px" height="200px">抱歉！浏览器不支持。</canvas>
 <canvas id="xttblog02" width="150px" height="150px">抱歉！浏览器不支持。</canvas>
 <button id="tupBtn" class="taoge_btn"></button>
</div>
<!-- 更改系统默认弹窗 -->
<script type="text/javascript">
window.alert = function(str)
{
 var shield = document.createElement("DIV");
 shield.id = "shield";
 shield.style.position = "absolute";
 shield.style.left = "50%";
 shield.style.top = "50%";
 shield.style.width = "280px";
 shield.style.height = "150px";
 shield.style.marginLeft = "-140px";
 shield.style.marginTop = "-110px";
 shield.style.zIndex = "25";
 var alertFram = document.createElement("DIV");
 alertFram.id="alertFram";
 alertFram.style.position = "absolute";
 alertFram.style.width = "280px";
 alertFram.style.height = "150px";
 alertFram.style.left = "50%";
 alertFram.style.top = "50%";
 alertFram.style.marginLeft = "-140px";
 alertFram.style.marginTop = "-110px";
 alertFram.style.textAlign = "center";
 alertFram.style.lineHeight = "150px";
 alertFram.style.zIndex = "300";
 strHtml = "<ul style=\"list-style:none;margin:0px;padding:0px;width:100%\">\n";
 strHtml += " <li style=\"background:#626262;text-align:left;padding-left:20px;font-size:14px;font-weight:bold;height:25px;line-height:25px;border:1px solid #F9CADE;color:white\">[中奖提醒]</li>\n";
 strHtml += " <li style=\"background:#787878;text-align:center;font-size:12px;height:95px;line-height:95px;border-left:1px solid #F9CADE;border-right:1px solid #F9CADE;color:#DCC722\">"+str+"</li>\n";
 strHtml += " <li style=\"background:#626262;text-align:center;font-weight:bold;height:30px;line-height:25px; border:1px solid #F9CADE;\"><input type=\"button\" value=\"确 定\" onclick=\"doOk()\" style=\"width:80px;height:20px;background:#626262;color:white;border:1px solid white;font-size:14px;line-height:20px;outline:none;margin-top: 4px\"/></li>\n";
 strHtml += "</ul>\n";
 alertFram.innerHTML = strHtml;
 document.body.appendChild(alertFram);
 document.body.appendChild(shield);
 this.doOk = function(){
  alertFram.style.display = "none";
  shield.style.display = "none";
 }
 alertFram.focus();
 document.body.onselectstart = function(){return false;};
}
</script>
</body>
</html>
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