兩款已久的雪花特效
阿新 • • 發佈：2018-06-05
animate radi 兩種 擺動 cos loop min frame RR
一、下雪特效代碼①
1 <script type="text/javascript"> 2 (function($){ 3 $.fn.snow = function(options){ 4 var $flake = $(‘<div id="snowbox" />‘).css({‘position‘: ‘absolute‘,‘z-index‘:‘9999‘, ‘top‘: ‘-50px‘}).html(‘?‘), 5 documentHeight = $(document).height(), 6 documentWidth = $(document).width(),7 defaults = { 8 minSize : 10, 9 maxSize : 20, 10 newOn : 1000, 11 flakeColor : "#AFDAEF" /* 此處可以定義雪花顏色，若要白色可以改為#FFFFFF */ 12 }, 13 options = $.extend({}, defaults, options); 14 var interval= setInterval( function(){ 15var startPositionLeft = Math.random() * documentWidth - 100, 16 startOpacity = 0.5 + Math.random(), 17 sizeFlake = options.minSize + Math.random() * options.maxSize, 18 endPositionTop = documentHeight - 200, 19 endPositionLeft = startPositionLeft - 500 + Math.random() * 500,20 durationFall = documentHeight * 10 + Math.random() * 5000; 21 $flake.clone().appendTo(‘body‘).css({ 22 left: startPositionLeft, 23 opacity: startOpacity, 24 ‘font-size‘: sizeFlake, 25 color: options.flakeColor 26 }).animate({ 27 top: endPositionTop, 28 left: endPositionLeft, 29 opacity: 0.2 30 },durationFall,‘linear‘,function(){ 31 $(this).remove() 32 }); 33 }, options.newOn); 34 }; 35 })(jQuery); 36 $(function(){ 37 $.fn.snow({ 38 minSize: 5, /* 定義雪花最小尺寸 */ 39 maxSize: 50,/* 定義雪花最大尺寸 */ 40 newOn: 300 /* 定義密集程度，數字越小越密集 */ 41 }); 42 }); 43 </script>
二、下雪特效代碼②
1 <script type="text/javascript"> 2 /* 控制下雪 */ 3 function snowFall(snow) { 4 /* 可配置屬性 */ 5 snow = snow || {}; 6 this.maxFlake = snow.maxFlake || 200; /* 最多片數 */ 7 this.flakeSize = snow.flakeSize || 10; /* 雪花形狀 */ 8 this.fallSpeed = snow.fallSpeed || 1; /* 墜落速度 */ 9 } 10 /* 兼容寫法 */ 11 requestAnimationFrame = window.requestAnimationFrame || 12 window.mozRequestAnimationFrame || 13 window.webkitRequestAnimationFrame || 14 window.msRequestAnimationFrame || 15 window.oRequestAnimationFrame || 16 function(callback) { setTimeout(callback, 1000 / 60); }; 17 18 cancelAnimationFrame = window.cancelAnimationFrame || 19 window.mozCancelAnimationFrame || 20 window.webkitCancelAnimationFrame || 21 window.msCancelAnimationFrame || 22 window.oCancelAnimationFrame; 23 /* 開始下雪 */ 24 snowFall.prototype.start = function(){ 25 /* 創建畫布 */ 26 snowCanvas.apply(this); 27 /* 創建雪花形狀 */ 28 createFlakes.apply(this); 29 /* 畫雪 */ 30 drawSnow.apply(this) 31 } 32 /* 創建畫布 */ 33 function snowCanvas() { 34 /* 添加Dom結點 */ 35 var snowcanvas = document.createElement("canvas"); 36 snowcanvas.id = "snowfall"; 37 snowcanvas.width = window.innerWidth; 38 snowcanvas.height = document.body.clientHeight; 39 snowcanvas.setAttribute("style", "position:absolute; top: 0; left: 0; z-index: 1; pointer-events: none;"); 40 document.getElementsByTagName("body")[0].appendChild(snowcanvas); 41 this.canvas = snowcanvas; 42 this.ctx = snowcanvas.getContext("2d"); 43 /* 窗口大小改變的處理 */ 44 window.onresize = function() { 45 snowcanvas.width = window.innerWidth; 46 /* snowcanvas.height = window.innerHeight */ 47 } 48 } 49 /* 雪運動對象 */ 50 function flakeMove(canvasWidth, canvasHeight, flakeSize, fallSpeed) { 51 this.x = Math.floor(Math.random() * canvasWidth); /* x坐標 */ 52 this.y = Math.floor(Math.random() * canvasHeight); /* y坐標 */ 53 this.size = Math.random() * flakeSize + 2; /* 形狀 */ 54 this.maxSize = flakeSize; /* 最大形狀 */ 55 this.speed = Math.random() * 1 + fallSpeed; /* 墜落速度 */ 56 this.fallSpeed = fallSpeed; /* 墜落速度 */ 57 this.velY = this.speed; /* Y方向速度 */ 58 this.velX = 0; /* X方向速度 */ 59 this.stepSize = Math.random() / 30; /* 步長 */ 60 this.step = 0 /* 步數 */ 61 } 62 flakeMove.prototype.update = function() { 63 var x = this.x, 64 y = this.y; 65 /* 左右擺動(余弦) */ 66 this.velX *= 0.98; 67 if (this.velY <= this.speed) { 68 this.velY = this.speed 69 } 70 this.velX += Math.cos(this.step += .05) * this.stepSize; 71 72 this.y += this.velY; 73 this.x += this.velX; 74 /* 飛出邊界的處理 */ 75 if (this.x >= canvas.width || this.x <= 0 || this.y >= canvas.height || this.y <= 0) { 76 this.reset(canvas.width, canvas.height) 77 } 78 }; 79 /* 飛出邊界-放置最頂端繼續墜落 */ 80 flakeMove.prototype.reset = function(width, height) { 81 this.x = Math.floor(Math.random() * width); 82 this.y = 0; 83 this.size = Math.random() * this.maxSize + 2; 84 this.speed = Math.random() * 1 + this.fallSpeed; 85 this.velY = this.speed; 86 this.velX = 0; 87 }; 88 // 渲染雪花-隨機形狀（此處可修改雪花顏色！！！） 89 flakeMove.prototype.render = function(ctx) { 90 var snowFlake = ctx.createRadialGradient(this.x, this.y, 0, this.x, this.y, this.size); 91 snowFlake.addColorStop(0, "rgba(255, 255, 255, 0.9)"); /* 此處是雪花顏色，默認是白色 */ 92 snowFlake.addColorStop(.5, "rgba(255, 255, 255, 0.5)"); /* 若要改為其他顏色，請自行查 */ 93 snowFlake.addColorStop(1, "rgba(255, 255, 255, 0)"); /* 找16進制的RGB 顏色代碼。 */ 94 ctx.save(); 95 ctx.fillStyle = snowFlake; 96 ctx.beginPath(); 97 ctx.arc(this.x, this.y, this.size, 0, Math.PI * 2); 98 ctx.fill(); 99 ctx.restore(); 100 }; 101 /* 創建雪花-定義形狀 */ 102 function createFlakes() { 103 var maxFlake = this.maxFlake, 104 flakes = this.flakes = [], 105 canvas = this.canvas; 106 for (var i = 0; i < maxFlake; i++) { 107 flakes.push(new flakeMove(canvas.width, canvas.height, this.flakeSize, this.fallSpeed)) 108 } 109 } 110 /* 畫雪 */ 111 function drawSnow() { 112 var maxFlake = this.maxFlake, 113 flakes = this.flakes; 114 ctx = this.ctx, canvas = this.canvas, that = this; 115 /* 清空雪花 */ 116 ctx.clearRect(0, 0, canvas.width, canvas.height); 117 for (var e = 0; e < maxFlake; e++) { 118 flakes[e].update(); 119 flakes[e].render(ctx); 120 } 121 /* 一幀一幀的畫 */ 122 this.loop = requestAnimationFrame(function() { 123 drawSnow.apply(that); 124 }); 125 } 126 /* 調用及控制方法 */ 127 var snow = new snowFall({maxFlake:60}); 128 snow.start(); 129 </script>
使用方法：
方法①、復制其中一種JS代碼，粘貼到網站</body>標簽之前即可；
方法②、去掉代碼前後的<script **>標簽，然後將代碼保存為js文件，最後在網站引用即可。
Ps：若沒效果，請確認網頁是否已載入JQurey，如果沒有請在下雪代碼之前引入JQ即可。
載入jquery
1 <script type="text/javascript" src="http://libs.baidu.com/jquery/1.8.3/jquery.js"></script> 2 <script type="text/javascript" src="http://libs.baidu.com/jquery/1.8.3/jquery.min.js"></script>
註意:
本文轉自鏈接： https://ihuan.me/2172.html
兩款已久的雪花特效