先上結果，後附代碼
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>show</title>
</head>
<body>
<div id="show">
<canvas id="showData" style="height: 20px;width: 300px;"></canvas>
</div>
</body>
<script src="index.js"></script>
</html>
index.js
var loadeds = 0;
/*========================================================*/
/* Light Loader
/*========================================================*/
var lightLoader = function (c, cw, ch) {
var _this = this;
this.c = c;
this.ctx = c.getContext('2d');
this.cw = 300; //父類寬
this.ch = 150; //父類高
this.loaded = startScores;
this.loaderSpeed = .6; //加載速度
this.loaderHeight = 50; //進度條高度
this.loaderWidth = 120; //默認進度條長度
this.loader = {
x: (this.cw / 2) - (this.loaderWidth / 2),
y: (this.ch / 2) - (this.loaderHeight / 2)
};
this.particles = [];
this.particleLift = 180; //光粒子上揚的高度
this.hueStart = 0; //顏色漸變的初始顏色
this.hueEnd = 120; //漸變的顏色選擇
this.hue = 0;
this.gravity = .15; //光粒子上揚的角度
this.particleRate = 2; //光粒子的數量
/*========================================================*/
/* 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 是否循環加載 ,
/*========================================================*/
this.updateLoader = function () {
if (this.loaded < scores) {
this.loaded += this.loaderSpeed;
loadeds = this.loaded;
} else {
if (flog) {
this.loaded = startScores;
loadeds = startScores;
} else {
if (this.loaded >= 99) {
this.particleRate = 0;
}
}
}
};
/*========================================================*/
/* Render Loader
/*========================================================*/
this.renderLoader = function () {
this.ctx.fillStyle = '#000'; //進度條的底層顏色
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
/*========================================================*/
var scores = 100;
var startScores = 0;
var flog = false;
function showProgressBar(id, num1, num2, boo) {
scores = num2;
if (scores > 100) {
scores = 100;
}
startScores = num1;
flog = boo;
var c = document.getElementById(id);
// var cw = c.width;
var cw = c.offsetWidth;
// var ch = c.height;
var ch = c.offsetHeight;
// document.body.appendChild(c);
var cl = new lightLoader(c, cw, ch);
setupRAF();
cl.init();
}
// 進度條控制方法
showProgressBar("showData",0,100,true); // id ,開始 分數 ,循環
function getLoaded() {
return loadeds;
}
function setScores(){
loadeds = 0;
}