js如何实现抽奖转盘

2024-12-04 技术教程

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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

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

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 interfaceWilq32=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 dependencyjQuery(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 dependencyjQuery(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 IEthis._container.appendChild(this._vimage);this._rootObj.appendChild(this._container);this._rootObj.style.position="relative"; // FIXES IE PROBLEMthis._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);}elsereturn 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 optimisationthis._heightHalf=this._height/2;// used for optimisationvar _widthMax=Math.sqrt((this._height)*(this._height) + (this._width) * (this._width));this._widthAdd = _widthMax - this._width;this._heightAdd = _widthMax - this._height;// widthMax because maxWidth=maxHeightthis._widthAddHalf=this._widthAdd/2; // used for optimisationthis._heightAddHalf=this._heightAdd/2;// used for optimisationthis._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 canvasthis._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 screenthis._cnv.translate(this._widthHalf,this._heightHalf);// we move image back to its orginal this._cnv.rotate(angle);// rotate imagethis._cnv.translate(-this._widthHalf,-this._heightHalf);// move image to its center, so we can rotate around its centerthis._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);

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