HTML5超酷粒子效果的進度條的實作範例

這是一款基於HTML5和JavaScript的進度條應用，這款進度條插件非常有特點，它在進度展示的時候呈現粒子的動畫效果，也就是說，進度條在滑動的同時，會產生一些小粒子掉落下來，效果非常酷。另外還有一個特點是隨著進度的變化，進度條的顏色也會改變。

JavaScript程式碼

 /*================================================== ========*/ /* Light Loader/*================================== ======================*/var lightLoader = function(c, cw, ch){ var _this = this; this.c = c; this.ctx = c.getContext('2d'); this.cw = cw; this.ch = ch; this.loaded = 0; this.loaderSpeed = .6; this.loaderHeight = 10; this.loaderWidth = 310; this.loader = { x: (this.cw/2) - (this.loaderWidth/2), y: (this.ch/2) - (this.loaderHeight/2) }; this.particles = []; this.particleLift = 180; this.hueStart = 0 this.hueEnd = 120; this.hue = 0; this.gravity = .15; this.particleRate = 0; this.gravity = .15; this.particleRate = 4; /*================================================ ========*/ /* Initialize /*=================================== =====================*/ this.init = function(){ this.loop(); }; /*================================================ ========*/ /* Utility Functions /*================================== ======================*/ this.rand = function(rMi, rMa){return ~~((Math.random()*(rMa-rMi+1))+rMi);}; this.hitTest = function(x1, y1, w1, h1, x2, y2, w2, h2){return !( x1 + w1 < x2 || x2 + w2 < x1 || y1 + h1 < y2 || y2 + h2 < y1);}; /*================================================== ========*/ /* Update Loader /*================================== ======================*/ this.updateLoader = function(){ if(this.loaded < 100){ this.loaded += this.loaderSpeed; } else { this.loaded = 0; } }; /*==================================== ====================*/ /* Render Loader /*====================== ==================================*/ this.renderLoader = function(){ this.ctx.fillStyle = '#000'; this.ctx.fillRect(this.loader.x, this.loader.y, this.loaderWidth, this.loaderHeight); this.hue = this.hueStart + (this.loaded/100)*(this .hueEnd - this.hueStart); var newWidth = (this.loaded/100)*this.loaderWidth; this.ctx.fillStyle = 'hsla('+this.hue+', 100%, 40%, 1)'; this.ctx.fillRect(this.loader.x, this.loader.y, newWidth, this.loaderHeight) ; this.ctx.fillStyle = '#222'; this.ctx.fillRect(this.loader.x, this.loader.y, newWidth, this.loaderHeight/2); }; /*===================== =====================================*/ /* Particles /*====== ================================================== */ this.Particle = function(){ this.x = _this.loader.x + ((_this.loaded/100)*_this.loaderWidth) - _this.rand(0, 1); this.y = _this.ch/2 + _this.rand(0,_this.loaderHeight)-_this.loaderHeight/2; this.vx = (_this.rand(0,4)-2)/100; this.vy = (_this.rand(0,_this.particleLift)-_this.particleLift*2)/100; this.width = _this.rand(1, 4)/2; this.height = _this.rand(1,4)/2; this.hue = _this.hue; }; this.Particle.prototype.update = function(i){ this.vx += (_this.rand(0,6)-3)/100; this.vy += _this.gravity; this.x += this.vx ; this.y += this.vy; if(this.y > _this.ch){ _this.particles.splice(i, 1); } }; this.Particle.prototype.render = function(){ _this.ctx.fillStyle = 'hsla('+this.hue+', 100%, '+_this.rand(50,70)+'%, '+_this .rand(20,100)/100+')'; _this.ctx.fillRect(this.x, this.y, this.width, this.height); }; this.createParticles = function(){ var i = this.particleRate; while(i--){ this.particles.push(new this.Particle()); }; }; ; this.updateParticles = function(){ var i = this.particles.length; while(i--){ var p = this.particles[i]; p.update(i); }; }; this.renderParticles = function(){ var i = this.particles.length; while(i--){ var p = this.particles[i ]; p.render(); }; }; /*==================================== ====================*/ /* Clear Canvas /*============================================ ============*/ this.clearCanvas = function(){ this.ctx.globalCompositeOperation = 'source-over'; this.ctx.clearRect(0,0,this.cw,this. ch); this.ctx.globalCompositeOperation = 'lighter'; }; /*============================================ ==============*/ /* Animation Loop /*============================ ============================*/ this.loop = function(){ var loopIt = function(){ requestAnimationFrame(loopIt, _this.c); _this.clearCanvas(); _this.createParticles(); _this.updateLoader(); _this.updateParticles(); _this.renderLoader(); _this.renderParticles(); }; loopIt(); };};/*============================================== ============*/ /* Check Canvas Support/*============================= ===========================*/var isCanvasSupported = function(){ var elem = document.createElement('canvas'); return !!(elem.getContext && elem.getContext('2d'));};/*=============================== ===========================*/ /* Setup requestAnimationFrame/*=============== =========================================*/var setupRAF = function(){ var lastTime = 0; var vendors = ['ms', 'moz', 'webkit', 'o']; for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x){ window .requestAnimationFrame = window[vendors[x]+'RequestAnimationFrame']; window.cancelAnimationFrame = window[vendors[x]+'CancelAnimationFrame'] || window[vendors[x]+'CancelRequestAnimationFrame']; }; if(!window.requestAnimationFrame){ window.requestAnimationFrame = function(callback, elAnimationFrame){ window.requestAnimationFrame = function(callback, elAnimationFrame){ window.requestAnimationFrame = function(callback, elAnimationFrame){ window.requestAnimationFrame = function(callback, elAnimationFrame){ currTime Date().getTime(); var timeToCall = Math.max(0, 16 - (currTime - lastTime)); var id = window.setTimeout(function() { callback(currTime + timeToCall); }, timeToCall); lastTime = currTime + timeToCall; return id; }; }; if (!window. cancelAnimationFrame){ window.cancelAnimationFrame = function(id){ clearTimeout(id); }; };}; /*===================================== ===================*/ /* Define Canvas and Initialize/*===================== ===================================*/if(isCanvasSupported){ var c = document.createElement('canvas'); c.width = 400; c.height = 100; var cw = c.width; var ch = c.height; document.body.appendChild(c); var cl = new lightLoader( c, cw, ch); setupRAF(); cl.init();}

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