很漂亮的一个背景控件——ribbons.js

(function (name, factory) {
if (typeof window === "object") {
window[name] = factory();
}
})
("Ribbons", function () {
var _w = window, _b = document.body, _d = document.documentElement; //随机函数
var random = function () {
if (arguments.length === 1) {
if (Array.isArray(arguments[0])) {
var index = Math.round(random(0, arguments[0].length - 1));
return arguments[0][index];
}
return random(0, arguments[0]);
} else
if (arguments.length === 2) {
return Math.random() * (arguments[1] - arguments[0]) + arguments[0];
}
return 0;
}; //屏幕信息
var screenInfo = function (e) {
var width = Math.max(0, _w.innerWidth || _d.clientWidth || _b.clientWidth || 0),
height = Math.max(0, _w.innerHeight || _d.clientHeight || _b.clientHeight || 0),
scrollx = Math.max(0, _w.pageXOffset || _d.scrollLeft || _b.scrollLeft || 0) - (_d.clientLeft || 0),
scrolly = Math.max(0, _w.pageYOffset || _d.scrollTop || _b.scrollTop || 0) - (_d.clientTop || 0);
return {
width: width,
height: height,
ratio: width / height,
centerx: width / 2,
centery: height / 2,
scrollx: scrollx,
scrolly: scrolly
};
}; var mouseInfo = function (e) {
var screen = screenInfo(e),
mousex = e ? Math.max(0, e.pageX || e.clientX || 0) : 0,
mousey = e ? Math.max(0, e.pageY || e.clientY || 0) : 0; return {
mousex: mousex,
mousey: mousey,
centerx: mousex - screen.width / 2,
centery: mousey - screen.height / 2
};
}; //点
var Point = function (x, y) {
this.x = 0;
this.y = 0;
this.set(x, y);
};
//点运算
Point.prototype = {
constructor: Point,
set: function (x, y) {
this.x = x || 0; this.y = y || 0;
},
copy: function (point) {
this.x = point.x || 0; this.y = point.y || 0; return this;
},
multiply: function (x, y) {
this.x *= x || 1; this.y *= y || 1; return this;
},
divide: function (x, y) {
this.x /= x || 1; this.y /= y || 1; return this;
},
add: function (x, y) {
this.x += x || 0; this.y += y || 0; return this;
},
subtract: function (x, y) {
this.x -= x || 0; this.y -= y || 0; return this;
},
clampX: function (min, max) {
this.x = Math.max(min, Math.min(this.x, max)); return this;
},
clampY: function (min, max) {
this.y = Math.max(min, Math.min(this.y, max)); return this;
},
flipX: function () {
this.x *= -1; return this;
},
flipY: function () {
this.y *= -1; return this;
}
}; //丝带画板
var Factory = function (options) {
this._canvas = null;
this._context = null;
this._sto = null;
this._width = 0;
this._height = 0;
this._scroll = 0;
this._ribbons = [];
this._options = {
id: "bgCanvas",//画板Id
backgroundColor: "#1f1f1f",//画板背景
colorSaturation: "80%",//纯度
colorBrightness: "60%",//亮度
colorAlpha: 0.65,//透明度
colorCycleSpeed: 6,//丝带不同块之间的色彩变化量
verticalPosition: "center",//丝带相对于屏幕的初始位置：top/min 屏幕最上方，middle|center 中间，bottom|max 屏幕最下面
horizontalSpeed: 200,//丝带水平方向移动速度参数（会乘以一个随机值）
ribbonCount: 3,//同一时间丝带总条数
strokeSize: 0,//公共边路径样式
parallaxAmount: -0.5,//滚动偏移参数，-1表示不偏移，0表示基于丝带只出现在页面最上面
animateSections: true//丝带块是否偏移，显得有动感
};
this._onDraw = this._onDraw.bind(this);
this._onResize = this._onResize.bind(this);
this._onScroll = this._onScroll.bind(this);
this.setOptions(options);
this.init();
};
Factory.prototype = {
constructor: Factory,
setOptions: function (options) {
if (typeof options === "object") {
for (var key in options) {
if (options.hasOwnProperty(key)) {
this._options[key] = options[key];
}
}
}
},
//初始化
init: function () {
//初始化画板
try {
this._canvas = document.createElement("canvas");
this._canvas.style["display"] = "block";
this._canvas.style["position"] = "fixed";
this._canvas.style["margin"] = "0";
this._canvas.style["padding"] = "0";
this._canvas.style["border"] = "0";
this._canvas.style["outline"] = "0";
this._canvas.style["left"] = "0";
this._canvas.style["top"] = "0";
this._canvas.style["width"] = "100%";
this._canvas.style["height"] = "100%";
this._canvas.style["z-index"] = "-1";
this._canvas.style["background-color"] = this._options.backgroundColor;
this._canvas.id = this._options.id;
this._onResize();
this._context = this._canvas.getContext("2d");
this._context.clearRect(0, 0, this._width, this._height);
this._context.globalAlpha = this._options.colorAlpha;
window.addEventListener("resize", this._onResize);
window.addEventListener("scroll", this._onScroll);
document.body.appendChild(this._canvas);
}
catch (e) {
console.warn("Canvas Context Error: " + e.toString());
return;
}
//开始绘画
this._onDraw();
},
//生成一条丝带
addRibbon: function () {
var dir = Math.round(random(1, 9)) > 5 ? "right" : "left",//丝带延伸方向
stop = 1000,
hide = 200,
min = 0 - hide,
max = this._width + hide,
movex = 0,
movey = 0,
startx = dir === "right" ? min : max,//起始点x左边
starty = Math.round(random(0, this._height));//起始点y左边 //丝带生成的位置
if (/^(top|min)$/i.test(this._options.verticalPosition)) {//最上方
starty = 0 + hide;
} else if (/^(middle|center)$/i.test(this._options.verticalPosition)) {//中间
starty = this._height / 2;
} else if (/^(bottom|max)$/i.test(this._options.verticalPosition)) {//最下方
starty = this._height - hide;
} if (this._options.parallaxAmount !== 0) {
starty += this._scroll;//加上滚动
} var ribbon = [],
point1 = new Point(startx, starty),
point2 = new Point(startx, starty),
point3 = null,
color = Math.round(random(0, 360)),
delay = 0; //从起始位置开始生成一条丝带
//丝带每个分部都是一个三角形，三点确定一个三角形，相邻三角形有一条公共边
while (true) {
if (stop <= 0) break;
stop--;
movex = Math.round((Math.random() * 1 - 0.2) * this._options.horizontalSpeed);
movey = Math.round((Math.random() * 1 - 0.5) * (this._height * 0.25));
point3 = new Point();
point3.copy(point2);
if (dir === "right") {
point3.add(movex, movey);
if (point2.x >= max) break;
} else if (dir === "left") {
point3.subtract(movex, movey);
if (point2.x <= min) break;
}
ribbon.push({
//三点
point1: new Point(point1.x, point1.y),
point2: new Point(point2.x, point2.y),
point3: point3,
color: color,//丝带颜色
delay: delay,//延迟消失
dir: dir,//方向
alpha: 0,//透明度
phase: 0 //随机位移有关参数
});
//公共边
point1.copy(point2);
point2.copy(point3);
delay += 4;
color += this._options.colorCycleSpeed;
}
this._ribbons.push(ribbon);
},
//绘制一个三角形方块
_drawRibbonSection: function (section) {
if (section) {
if (section.phase >= 1 && section.alpha <= 0) {
return true;
}
if (section.delay <= 0) {
section.phase += 0.02;
section.alpha = Math.sin(section.phase) * 1;
section.alpha = section.alpha <= 0 ? 0 : section.alpha;
section.alpha = section.alpha >= 1 ? 1 : section.alpha;
if (this._options.animateSections) {
var mod = Math.sin(1 + section.phase * Math.PI / 2) * 0.1;
if (section.dir === "right") {
section.point1.add(mod, 0);
section.point2.add(mod, 0);
section.point3.add(mod, 0);
} else {
section.point1.subtract(mod, 0);
section.point2.subtract(mod, 0);
section.point3.subtract(mod, 0);
}
section.point1.add(0, mod);
section.point2.add(0, mod);
section.point3.add(0, mod);
}
} else {
section.delay -= 0.5;
}
var s = this._options.colorSaturation,
l = this._options.colorBrightness,
c = "hsla(" + section.color + ", " + s + ", " + l + ", " + section.alpha + " )"; //绘制一个方块
this._context.save();
if (this._options.parallaxAmount !== 0) {
this._context.translate(0, this._scroll * this._options.parallaxAmount);
}
this._context.beginPath();
this._context.moveTo(section.point1.x, section.point1.y);
this._context.lineTo(section.point2.x, section.point2.y);
this._context.lineTo(section.point3.x, section.point3.y);
this._context.fillStyle = c;
this._context.fill();
if (this._options.strokeSize > 0) {
this._context.lineWidth = this._options.strokeSize;
this._context.strokeStyle = c;
this._context.lineCap = "round";
this._context.stroke();
}
this._context.restore();
}
return false;
},
//绘制丝带
_onDraw: function () {
//清空已经绘制过的丝带
for (var i = 0, t = this._ribbons.length; i < t; ++i) {
if (!this._ribbons[i]) {
this._ribbons.splice(i, 1);
}
}
this._context.clearRect(0, 0, this._width, this._height);//清空画板
for (var a = 0; a < this._ribbons.length; ++a) {
var ribbon = this._ribbons[a],
numSections = ribbon ? ribbon.length : 0,
numDone = 0; //绘制整条丝带
for (var b = 0; b < numSections; ++b) {
if (this._drawRibbonSection(ribbon[b])) {
numDone++;
}
}
//丝带已经全部飘过屏幕，设置为null,函数前面会自动清理
if (numDone >= numSections) {
this._ribbons[a] = null;
}
}
//随机生成一条丝带
if (this._ribbons.length < this._options.ribbonCount && Math.random() > 0.99) {
this.addRibbon();
} //调度交给系统，当需要刷新画板时调用指定的回调函数，用于提高性能
requestAnimationFrame(this._onDraw);
},
//重新设置窗体大小时需要获取窗体大小
_onResize: function (e) {
var screen = screenInfo(e);
this._width = screen.width;
this._height = screen.height;
if (this._canvas) {
this._canvas.width = this._width;
this._canvas.height = this._height;
if (this._context) {
this._context.globalAlpha = this._options.colorAlpha;
}
}
},
//滚动时获取滚动距离
_onScroll: function (e) {
var screen = screenInfo(e);
this._scroll = screen.scrolly;
}
}; return Factory;
}); //初始化并绘制
new Ribbons({
ribbonCount: 5,
parallaxAmount: -0.99
});

//初始化并绘制
new Ribbons({
ribbonCount: 5,
parallaxAmount: -0.99
});

options = {
id: "bgCanvas",//画板Id
backgroundColor: "#1f1f1f",//画板背景
colorSaturation: "80%",//纯度
colorBrightness: "60%",//亮度
colorAlpha: 0.65,//透明度
colorCycleSpeed: 6,//丝带不同块之间的色彩变化量
verticalPosition: "center",//丝带相对于屏幕的初始位置：top/min 屏幕最上方，middle|center 中间，bottom|max 屏幕最下面
horizontalSpeed: 200,//丝带水平方向移动速度参数（会乘以一个随机值）
ribbonCount: 3,//同一时间丝带总条数
strokeSize: 0,//公共边路径样式
parallaxAmount: -0.5,//滚动偏移参数，-1表示不偏移，0表示基于丝带只出现在页面最上面
animateSections: true//丝带块是否偏移，显得有动感
};

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Ribbons</title>
</head>
<body>
<!--这里最好在body的最后面引用js文件-->
<!--本地-->
<script src="ribbons.js"></script>
<!--远程-->
<!--<script src="https://blog-static.cnblogs.com/files/shanfeng1000/ribbons.js"></script>-->
</body>
</html>