js抽奖转盘实现方法分析
程序员文章站
2022-06-17 14:23:12
本文实例讲述了js抽奖转盘实现方法。分享给大家供大家参考,具体如下:html 这里.left 固定了圆的宽度和高度,还有canvas也设置了固定宽高 绘制圆心的坐标也就出来了 (203,203)抽奖转...
本文实例讲述了js抽奖转盘实现方法。分享给大家供大家参考,具体如下:
html 这里.left 固定了圆的宽度和高度,还有canvas也设置了固定宽高 绘制圆心的坐标也就出来了 (203,203)
抽奖转盘是由一个大圆和一个内圆完成 ;大圆负责绘制上奖品 ,内圆负责确定指针的位置,指针直接使用图片,决定位置确定
<div class="left"> <div class="turnplate" style="background:#1bacff;border-radius: 50%"> <canvas class="item" id="wheelcanvas" width="406px" height="406px"></canvas> <img class="pointer" src="sp2/point.png"/> </div> </div>
外圆留空多少的问题
ps里查看间距是多少,此处圆心(203,203) 大圆的半径就是203-10 =193
这个数值在下图里设置
js
<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:193, //大转盘外圆的半径 192 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 = ["50元代金券", "升职加薪", "100元代金券", "财源滚滚", "200元代金券", "爱情甜蜜 ", "500元代金券", "变美变帅"]; turnplate.colors = ["#1b62ca", "#1bacff", "#1b62ca", "#1bacff","#1b62ca", "#1bacff", "#1b62ca", "#1bacff"]; 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 (){ 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]); /* switch (item) { case 1: rotatefn(252, turnplate.restaraunts[0]); break; case 2: rotatefn(216, turnplate.restaraunts[1]); break; case 3: rotatefn(180, turnplate.restaraunts[2]); break; case 4: rotatefn(144, turnplate.restaraunts[3]); break; case 5: rotatefn(108, turnplate.restaraunts[4]); break; case 6: rotatefn(72, turnplate.restaraunts[5]); break; case 7: rotatefn(36, turnplate.restaraunts[6]); break; case 8: rotatefn(360, turnplate.restaraunts[7]); break; case 9: rotatefn(324, turnplate.restaraunts[8]); break; case 10: rotatefn(288, turnplate.restaraunts[9]); break; } */ console.log(item); }); }); function rnd(n, m){ var random = math.floor(math.random()*(m-n+1)+n); 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);//圆周率/ 奖品数量除以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'; // 绘制圆 (弧形) 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(203, 203, turnplate.outsideradius, angle, angle + arc, false);//绘制外圆 ctx.arc(203, 203, turnplate.insideradius, angle + arc, angle, true);//绘制内圆 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 = "#fff";/*奖品文字颜色*/ 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("闪币")>0){ var img= document.getelementbyid("shan-img"); img.onload=function(){ ctx.drawimage(img,-15,10); }; ctx.drawimage(img,-15,10); }else if(text.indexof("谢谢参与")>=0){ var img= document.getelementbyid("sorry-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>
引用jquery
在加载以下js
/* ????????????? www.datouwang.com */ (function($) { var supportedcss,styles=document.getelementsbytagname("head")[0].style,tocheck="transformproperty webkittransform otransform mstransform moztransform".split(" "); for (var a=0;a<tocheck.length;a++) if (styles[tocheck[a]] !== undefined) supportedcss = tocheck[a]; // bad eval to preven google closure to remove it from code o_o // after compresion replace it back to var ie = 'v' == '\v' var ie = eval('"v"=="\v"'); jquery.fn.extend({ rotate:function(parameters) { if (this.length===0||typeof parameters=="undefined") return; if (typeof parameters=="number") parameters={angle:parameters}; var returned=[]; for (var i=0,i0=this.length;i<i0;i++) { var element=this.get(i); if (!element.wilq32 || !element.wilq32.photoeffect) { var paramclone = $.extend(true, {}, parameters); var newrotobject = new wilq32.photoeffect(element,paramclone)._rootobj; returned.push($(newrotobject)); } else { element.wilq32.photoeffect._handlerotation(parameters); } } return returned; }, getrotateangle: function(){ var ret = []; for (var i=0,i0=this.length;i<i0;i++) { var element=this.get(i); if (element.wilq32 && element.wilq32.photoeffect) { ret[i] = element.wilq32.photoeffect._angle; } } return ret; }, stoprotate: function(){ for (var i=0,i0=this.length;i<i0;i++) { var element=this.get(i); if (element.wilq32 && element.wilq32.photoeffect) { cleartimeout(element.wilq32.photoeffect._timer); } } } }); // library agnostic interface wilq32=window.wilq32||{}; wilq32.photoeffect=(function(){ if (supportedcss) { return function(img,parameters){ img.wilq32 = { photoeffect: this }; this._img = this._rootobj = this._eventobj = img; this._handlerotation(parameters); } } else { return function(img,parameters) { // make sure that class and id are also copied - just in case you would like to refeer to an newly created object this._img = img; this._rootobj=document.createelement('span'); this._rootobj.style.display="inline-block"; this._rootobj.wilq32 = { photoeffect: this }; img.parentnode.insertbefore(this._rootobj,img); if (img.complete) { this._loader(parameters); } else { var self=this; // todo: remove jquery dependency jquery(this._img).bind("load", function() { self._loader(parameters); }); } } } })(); wilq32.photoeffect.prototype={ _setupparameters : function (parameters){ this._parameters = this._parameters || {}; if (typeof this._angle !== "number") this._angle = 0 ; if (typeof parameters.angle==="number") this._angle = parameters.angle; this._parameters.animateto = (typeof parameters.animateto==="number") ? (parameters.animateto) : (this._angle); this._parameters.step = parameters.step || this._parameters.step || null; this._parameters.easing = parameters.easing || this._parameters.easing || function (x, t, b, c, d) { return -c * ((t=t/d-1)*t*t*t - 1) + b; } this._parameters.duration = parameters.duration || this._parameters.duration || 1000; this._parameters.callback = parameters.callback || this._parameters.callback || function(){}; if (parameters.bind && parameters.bind != this._parameters.bind) this._bindevents(parameters.bind); }, _handlerotation : function(parameters){ this._setupparameters(parameters); if (this._angle==this._parameters.animateto) { this._rotate(this._angle); } else { this._animatestart(); } }, _bindevents:function(events){ if (events && this._eventobj) { // unbinding previous events if (this._parameters.bind){ var oldevents = this._parameters.bind; for (var a in oldevents) if (oldevents.hasownproperty(a)) // todo: remove jquery dependency jquery(this._eventobj).unbind(a,oldevents[a]); } this._parameters.bind = events; for (var a in events) if (events.hasownproperty(a)) // todo: remove jquery dependency jquery(this._eventobj).bind(a,events[a]); } }, _loader:(function() { if (ie) return function(parameters) { var width=this._img.width; var height=this._img.height; this._img.parentnode.removechild(this._img); this._vimage = this.createvmlnode('image'); this._vimage.src=this._img.src; this._vimage.style.height=height+"px"; this._vimage.style.width=width+"px"; this._vimage.style.position="absolute"; // fixes ie problem - its only rendered if its on absolute position! this._vimage.style.top = "0px"; this._vimage.style.left = "0px"; /* group minifying a small 1px precision problem when rotating object */ this._container = this.createvmlnode('group'); this._container.style.width=width; this._container.style.height=height; this._container.style.position="absolute"; this._container.setattribute('coordsize',width-1+','+(height-1)); // this -1, -1 trying to fix ugly problem with small displacement on ie this._container.appendchild(this._vimage); this._rootobj.appendchild(this._container); this._rootobj.style.position="relative"; // fixes ie problem this._rootobj.style.width=width+"px"; this._rootobj.style.height=height+"px"; this._rootobj.setattribute('id',this._img.getattribute('id')); this._rootobj.classname=this._img.classname; this._eventobj = this._rootobj; this._handlerotation(parameters); } else return function (parameters) { this._rootobj.setattribute('id',this._img.getattribute('id')); this._rootobj.classname=this._img.classname; this._width=this._img.width; this._height=this._img.height; this._widthhalf=this._width/2; // used for optimisation this._heighthalf=this._height/2;// used for optimisation var _widthmax=math.sqrt((this._height)*(this._height) + (this._width) * (this._width)); this._widthadd = _widthmax - this._width; this._heightadd = _widthmax - this._height; // widthmax because maxwidth=maxheight this._widthaddhalf=this._widthadd/2; // used for optimisation this._heightaddhalf=this._heightadd/2;// used for optimisation this._img.parentnode.removechild(this._img); this._aspectw = ((parseint(this._img.style.width,10)) || this._width)/this._img.width; this._aspecth = ((parseint(this._img.style.height,10)) || this._height)/this._img.height; this._canvas=document.createelement('canvas'); this._canvas.setattribute('width',this._width); this._canvas.style.position="relative"; this._canvas.style.left = -this._widthaddhalf + "px"; this._canvas.style.top = -this._heightaddhalf + "px"; this._canvas.wilq32 = this._rootobj.wilq32; this._rootobj.appendchild(this._canvas); this._rootobj.style.width=this._width+"px"; this._rootobj.style.height=this._height+"px"; this._eventobj = this._canvas; this._cnv=this._canvas.getcontext('2d'); this._handlerotation(parameters); } })(), _animatestart:function() { if (this._timer) { cleartimeout(this._timer); } this._animatestarttime = +new date; this._animatestartangle = this._angle; this._animate(); }, _animate:function() { var actualtime = +new date; var checkend = actualtime - this._animatestarttime > this._parameters.duration; // todo: bug for animatedgif for static rotation ? (to test) if (checkend && !this._parameters.animatedgif) { cleartimeout(this._timer); } else { if (this._canvas||this._vimage||this._img) { var angle = this._parameters.easing(0, actualtime - this._animatestarttime, this._animatestartangle, this._parameters.animateto - this._animatestartangle, this._parameters.duration); this._rotate((~~(angle*10))/10); } if (this._parameters.step) { this._parameters.step(this._angle); } var self = this; this._timer = settimeout(function() { self._animate.call(self); }, 10); } // to fix bug that prevents using recursive function in callback i moved this function to back if (this._parameters.callback && checkend){ this._angle = this._parameters.animateto; this._rotate(this._angle); this._parameters.callback.call(this._rootobj); } }, _rotate : (function() { var rad = math.pi/180; if (ie) return function(angle) { this._angle = angle; this._container.style.rotation=(angle%360)+"deg"; } else if (supportedcss) return function(angle){ this._angle = angle; this._img.style[supportedcss]="rotate("+(angle%360)+"deg)"; } else return function(angle) { this._angle = angle; angle=(angle%360)* rad; // clear canvas this._canvas.width = this._width+this._widthadd; this._canvas.height = this._height+this._heightadd; // remember: all drawings are read from backwards.. so first function is translate, then rotate, then translate, translate.. this._cnv.translate(this._widthaddhalf,this._heightaddhalf); // at least center image on screen this._cnv.translate(this._widthhalf,this._heighthalf); // we move image back to its orginal this._cnv.rotate(angle); // rotate image this._cnv.translate(-this._widthhalf,-this._heighthalf); // move image to its center, so we can rotate around its center this._cnv.scale(this._aspectw,this._aspecth); // scale - if needed ;) this._cnv.drawimage(this._img, 0, 0); // first - we draw image } })() } if (ie) { wilq32.photoeffect.prototype.createvmlnode=(function(){ document.createstylesheet().addrule(".rvml", "behavior:url(#default#vml)"); try { !document.namespaces.rvml && document.namespaces.add("rvml", "urn:schemas-microsoft-com:vml"); return function (tagname) { return document.createelement('<rvml:' + tagname + ' class="rvml">'); }; } catch (e) { return function (tagname) { return document.createelement('<' + tagname + ' xmlns="urn:schemas-microsoft.com:vml" class="rvml">'); }; } })(); } })(jquery);
感兴趣的朋友可以使用在线html/css/javascript代码运行工具:http://tools.jb51.net/code/htmljsrun 测试上述代码运行效果。