原文链接：http://www.codeceo.com/article/html5-pixel-prograssbar.html
作者：码农网 – 小峰
这是一款基于HTML5和JavaScript的进度条应用，这款进度条插件非常有特点，它在进度展示的时候呈现粒子的动画效果，也就是说，进度条在滑动的同时，会产生一些小粒子掉落下来，效果非常酷。另外还有一个特点是随着进度的变化，进度条的颜色也会变化。
JavaScript代码
/*========================================================*/ /* 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 = 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, element){ var currTime = new 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();
}以上这款炫酷的HTML5进度条动画可以应用在不同风格的个人博客页面加载中，希望你喜欢。
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