jQuery移动端抽奖大转盘页面代码

使用方法：

如下：可以修改转盘图片、文字、中奖概率

<script type="text/javascript">
var turnplate={
		restaraunts:[],				//大转盘奖品名称
		colors:[],					//大转盘奖品区块对应背景颜色
		outsideRadius:192,			//大转盘外圆的半径
		textRadius:155,				//大转盘奖品位置距离圆心的距离
		insideRadius:68,			//大转盘内圆的半径
		startAngle:0,				//开始角度
		bRotate:false				//false:停止;ture:旋转
};

$(document).ready(function(){
	//动态添加大转盘的奖品与奖品区域背景颜色
	turnplate.restaraunts = ["20积分", "足疗机", "20积分", "保温杯", "20积分", "手持式电熨斗", "20积分 ", "橄榄油", "20积分", "晴雨伞"];
	turnplate.colors = ["#FFF4D6", "#FFFFFF", "#FFF4D6", "#FFFFFF","#FFF4D6", "#FFFFFF", "#FFF4D6", "#FFFFFF","#FFF4D6", "#FFFFFF"];
	var rotateTimeOut = function (){
		$('#wheelcanvas').rotate({
			angle:0,
			animateTo:2160,
			duration:8000,
			callback:function (){
				alert('网络超时，请检查您的网络设置！');
			}
		});
	};

	//旋转转盘 item:奖品位置; txt：提示语;
	var rotateFn = function (item, txt){
		var angles = item * (360 / turnplate.restaraunts.length) - (360 / (turnplate.restaraunts.length*2));
		if(angles<270){
			angles = 270 - angles; 
		}else{
			angles = 360 - angles + 270;
		}
		$('#wheelcanvas').stopRotate();
		$('#wheelcanvas').rotate({
			angle:0,
			animateTo:angles+1800,
			duration:8000,
			callback:function (){
				//中奖提示
				alert(txt);
				turnplate.bRotate = !turnplate.bRotate;
			}
		});
	};

	$('.pointer').click(function (){
		if(turnplate.bRotate)return;
		turnplate.bRotate = !turnplate.bRotate;
		//获取随机数(奖品个数范围内)
		var item = rnd(1,turnplate.restaraunts.length);
		//奖品数量等于10,指针落在对应奖品区域的中心角度[252, 216, 180, 144, 108, 72, 36, 360, 324, 288]
		rotateFn(item, turnplate.restaraunts[item-1]);

		console.log(item);
	});
});

function rnd(n, m){

	n=1;//最小随机数
	m=100;//最大随机数（概率范围最大值）
	//最大数数不超过最大随机数
	var ransluck = [50,60,65,70,75,80,85,90,95,100];//概率为比自己小的第一个数之间的差
	var randoms = Math.floor(Math.random()*(m-n+1)+n);
	if(randoms<=ransluck[0])
	{
		var random = 1;
	}
	else if(randoms<=ransluck[1])
	{
		var random = 2;
	}
	else if(randoms<=ransluck[2])
	{
		var random = 3;
	}
	else if(randoms<=ransluck[3])
	{
		var random = 4;
	}
	else if(randoms<=ransluck[4])
	{
		var random = 5;
	}
	else if(randoms<=ransluck[5])
	{
		var random = 6;
	}
	else if(randoms<=ransluck[6])
	{
		var random = 7;
	}
	else if(randoms<=ransluck[7])
	{
		var random = 8;
	}
	else if(randoms<=ransluck[8])
	{
		var random = 9;
	}
	else if(randoms<=ransluck[9])
	{
		var random = 10;
	}
	//alert(randoms);
	//alert(random);
	return random;
	
}


//页面所有元素加载完毕后执行drawRouletteWheel()方法对转盘进行渲染
window.onload=function(){
	drawRouletteWheel();
};

function drawRouletteWheel() {    
  var canvas = document.getElementById("wheelcanvas");    
  if (canvas.getContext) {
	  //根据奖品个数计算圆周角度
	  var arc = Math.PI / (turnplate.restaraunts.length/2);
	  var ctx = canvas.getContext("2d");
	  //在给定矩形内清空一个矩形
	  ctx.clearRect(0,0,422,422);
	  //strokeStyle 属性设置或返回用于笔触的颜色、渐变或模式  
	  ctx.strokeStyle = "#FFBE04";
	  //font 属性设置或返回画布上文本内容的当前字体属性
	  ctx.font = '16px Microsoft YaHei';      
	  for(var i = 0; i < turnplate.restaraunts.length; i++) {       
		  var angle = turnplate.startAngle + i * arc;
		  ctx.fillStyle = turnplate.colors[i];
		  ctx.beginPath();
		  //arc(x,y,r,起始角,结束角,绘制方向) 方法创建弧/曲线（用于创建圆或部分圆）    
		  ctx.arc(211, 211, turnplate.outsideRadius, angle, angle + arc, false);    
		  ctx.arc(211, 211, turnplate.insideRadius, angle + arc, angle, true);
		  ctx.stroke();  
		  ctx.fill();
		  //锁画布(为了保存之前的画布状态)
		  ctx.save();   
		  
		  //----绘制奖品开始----
		  ctx.fillStyle = "#E5302F";
		  var text = turnplate.restaraunts[i];
		  var line_height = 17;
		  //translate方法重新映射画布上的 (0,0) 位置
		  ctx.translate(211 + Math.cos(angle + arc / 2) * turnplate.textRadius, 211 + Math.sin(angle + arc / 2) * turnplate.textRadius);
		  
		  //rotate方法旋转当前的绘图
		  ctx.rotate(angle + arc / 2 + Math.PI / 2);
		  
		  /** 下面代码根据奖品类型、奖品名称长度渲染不同效果，如字体、颜色、图片效果。(具体根据实际情况改变) **/
		  if(text.indexOf("M")>0){//流量包
			  var texts = text.split("M");
			  for(var j = 0; j<texts.length; j++){
				  ctx.font = j == 0?'bold 20px Microsoft YaHei':'16px Microsoft YaHei';
				  if(j == 0){
					  ctx.fillText(texts[j]+"M", -ctx.measureText(texts[j]+"M").width / 2, j * line_height);
				  }else{
					  ctx.fillText(texts[j], -ctx.measureText(texts[j]).width / 2, j * line_height);
				  }
			  }
		  }else if(text.indexOf("M") == -1 && text.length>6){//奖品名称长度超过一定范围 
			  text = text.substring(0,6)+"||"+text.substring(6);
			  var texts = text.split("||");
			  for(var j = 0; j<texts.length; j++){
				  ctx.fillText(texts[j], -ctx.measureText(texts[j]).width / 2, j * line_height);
			  }
		  }else{
			  //在画布上绘制填色的文本。文本的默认颜色是黑色
			  //measureText()方法返回包含一个对象，该对象包含以像素计的指定字体宽度
			  ctx.fillText(text, -ctx.measureText(text).width / 2, 0);
		  }
		  
		  //添加对应图标
		  if(text.indexOf("分")>0){
			  var img= document.getElementById("fen-img");
			  img.onload=function(){  
				  ctx.drawImage(img,-15,10);      
			  }; 
			  ctx.drawImage(img,-15,10);  
		  }else if(text.indexOf("足疗")>=0){
			  var img= document.getElementById("zuliao-img");
			  img.onload=function(){  
				  ctx.drawImage(img,-15,10);      
			  };  
			  ctx.drawImage(img,-15,10);  
		  }
		  else if(text.indexOf("保温")>=0){
			  var img= document.getElementById("baowen-img");
			  img.onload=function(){
				  ctx.drawImage(img,-15,10);
			  };
			  ctx.drawImage(img,-15,10);
		  }
		  else if(text.indexOf("电熨斗")>=0){
			  var img= document.getElementById("yundou-img");
			  img.onload=function(){
				  ctx.drawImage(img,-15,10);
			  };
			  ctx.drawImage(img,-15,10);
		  }
		  else if(text.indexOf("橄榄")>=0){
			  var img= document.getElementById("ganlan-img");
			  img.onload=function(){
				  ctx.drawImage(img,-15,10);
			  };
			  ctx.drawImage(img,-15,10);
		  }
		  else if(text.indexOf("雨伞")>=0){
			  var img= document.getElementById("yusan-img");
			  img.onload=function(){
				  ctx.drawImage(img,-15,10);
			  };
			  ctx.drawImage(img,-15,10);
		  }

		  //把当前画布返回（调整）到上一个save()状态之前 
		  ctx.restore();
		  //----绘制奖品结束----
	  }     
  } 
}

</script>